-@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
+@c 2002, 2003 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@c prevent bad page break with this line
You can control the compilation driver.
-@table @code
-@findex SWITCH_TAKES_ARG
-@item SWITCH_TAKES_ARG (@var{char})
+@defmac SWITCH_TAKES_ARG (@var{char})
A C expression which determines whether the option @option{-@var{char}}
takes arguments. The value should be the number of arguments that
option takes--zero, for many options.
wish to add additional options which take arguments. Any redefinition
should call @code{DEFAULT_SWITCH_TAKES_ARG} and then check for
additional options.
+@end defmac
-@findex WORD_SWITCH_TAKES_ARG
-@item WORD_SWITCH_TAKES_ARG (@var{name})
+@defmac WORD_SWITCH_TAKES_ARG (@var{name})
A C expression which determines whether the option @option{-@var{name}}
takes arguments. The value should be the number of arguments that
option takes--zero, for many options. This macro rather than
wish to add additional options which take arguments. Any redefinition
should call @code{DEFAULT_WORD_SWITCH_TAKES_ARG} and then check for
additional options.
+@end defmac
-@findex SWITCH_CURTAILS_COMPILATION
-@item SWITCH_CURTAILS_COMPILATION (@var{char})
+@defmac SWITCH_CURTAILS_COMPILATION (@var{char})
A C expression which determines whether the option @option{-@var{char}}
stops compilation before the generation of an executable. The value is
boolean, nonzero if the option does stop an executable from being
options which affect the generation of an executable. Any redefinition
should call @code{DEFAULT_SWITCH_CURTAILS_COMPILATION} and then check
for additional options.
+@end defmac
-@findex SWITCHES_NEED_SPACES
-@item SWITCHES_NEED_SPACES
+@defmac SWITCHES_NEED_SPACES
A string-valued C expression which enumerates the options for which
the linker needs a space between the option and its argument.
If this macro is not defined, the default value is @code{""}.
+@end defmac
-@findex TARGET_OPTION_TRANSLATE_TABLE
-@item TARGET_OPTION_TRANSLATE_TABLE
+@defmac TARGET_OPTION_TRANSLATE_TABLE
If defined, a list of pairs of strings, the first of which is a
potential command line target to the @file{gcc} driver program, and the
second of which is a space-separated (tabs and other whitespace are not
@{ "-fast", "-march=fast-foo -malt-abi -I/usr/fast-foo" @}, \
@{ "-compat", "-EB -malign=4 -mspoo" @}
@end smallexample
+@end defmac
+
+@defmac DRIVER_SELF_SPECS
+A list of specs for the driver itself. It should be a suitable
+initializer for an array of strings, with no surrounding braces.
+
+The driver applies these specs to its own command line between loading
+default @file{specs} files (but not command-line specified ones) and
+choosing the multilib directory or running any subcommands. It
+applies them in the order given, so each spec can depend on the
+options added by earlier ones. It is also possible to remove options
+using @samp{%<@var{option}} in the usual way.
+
+This macro can be useful when a port has several interdependent target
+options. It provides a way of standardizing the command line so
+that the other specs are easier to write.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
-@findex CPP_SPEC
-@item CPP_SPEC
+@defmac OPTION_DEFAULT_SPECS
+A list of specs used to support configure-time default options (i.e.@:
+@option{--with} options) in the driver. It should be a suitable initializer
+for an array of structures, each containing two strings, without the
+outermost pair of surrounding braces.
+
+The first item in the pair is the name of the default. This must match
+the code in @file{config.gcc} for the target. The second item is a spec
+to apply if a default with this name was specified. The string
+@samp{%(VALUE)} in the spec will be replaced by the value of the default
+everywhere it occurs.
+
+The driver will apply these specs to its own command line between loading
+default @file{specs} files and processing @code{DRIVER_SELF_SPECS}, using
+the same mechanism as @code{DRIVER_SELF_SPECS}.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
+@defmac CPP_SPEC
A C string constant that tells the GCC driver program options to
pass to CPP@. It can also specify how to translate options you
give to GCC into options for GCC to pass to the CPP@.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex CPLUSPLUS_CPP_SPEC
-@item CPLUSPLUS_CPP_SPEC
+@defmac CPLUSPLUS_CPP_SPEC
This macro is just like @code{CPP_SPEC}, but is used for C++, rather
than C@. If you do not define this macro, then the value of
@code{CPP_SPEC} (if any) will be used instead.
+@end defmac
-@findex CC1_SPEC
-@item CC1_SPEC
+@defmac CC1_SPEC
A C string constant that tells the GCC driver program options to
pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language
front ends.
for GCC to pass to front ends.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex CC1PLUS_SPEC
-@item CC1PLUS_SPEC
+@defmac CC1PLUS_SPEC
A C string constant that tells the GCC driver program options to
pass to @code{cc1plus}. It can also specify how to translate options you
give to GCC into options for GCC to pass to the @code{cc1plus}.
Note that everything defined in CC1_SPEC is already passed to
@code{cc1plus} so there is no need to duplicate the contents of
CC1_SPEC in CC1PLUS_SPEC@.
+@end defmac
-@findex ASM_SPEC
-@item ASM_SPEC
+@defmac ASM_SPEC
A C string constant that tells the GCC driver program options to
pass to the assembler. It can also specify how to translate options
you give to GCC into options for GCC to pass to the assembler.
See the file @file{sun3.h} for an example of this.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex ASM_FINAL_SPEC
-@item ASM_FINAL_SPEC
+@defmac ASM_FINAL_SPEC
A C string constant that tells the GCC driver program how to
run any programs which cleanup after the normal assembler.
Normally, this is not needed. See the file @file{mips.h} for
an example of this.
Do not define this macro if it does not need to do anything.
+@end defmac
+
+@defmac AS_NEEDS_DASH_FOR_PIPED_INPUT
+Define this macro, with no value, if the driver should give the assembler
+an argument consisting of a single dash, @option{-}, to instruct it to
+read from its standard input (which will be a pipe connected to the
+output of the compiler proper). This argument is given after any
+@option{-o} option specifying the name of the output file.
+
+If you do not define this macro, the assembler is assumed to read its
+standard input if given no non-option arguments. If your assembler
+cannot read standard input at all, use a @samp{%@{pipe:%e@}} construct;
+see @file{mips.h} for instance.
+@end defmac
-@findex LINK_SPEC
-@item LINK_SPEC
+@defmac LINK_SPEC
A C string constant that tells the GCC driver program options to
pass to the linker. It can also specify how to translate options you
give to GCC into options for GCC to pass to the linker.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex LIB_SPEC
-@item LIB_SPEC
+@defmac LIB_SPEC
Another C string constant used much like @code{LINK_SPEC}. The difference
between the two is that @code{LIB_SPEC} is used at the end of the
command given to the linker.
If this macro is not defined, a default is provided that
loads the standard C library from the usual place. See @file{gcc.c}.
+@end defmac
-@findex LIBGCC_SPEC
-@item LIBGCC_SPEC
+@defmac LIBGCC_SPEC
Another C string constant that tells the GCC driver program
how and when to place a reference to @file{libgcc.a} into the
linker command line. This constant is placed both before and after
If this macro is not defined, the GCC driver provides a default that
passes the string @option{-lgcc} to the linker.
+@end defmac
-@findex STARTFILE_SPEC
-@item STARTFILE_SPEC
+@defmac STARTFILE_SPEC
Another C string constant used much like @code{LINK_SPEC}. The
difference between the two is that @code{STARTFILE_SPEC} is used at
the very beginning of the command given to the linker.
If this macro is not defined, a default is provided that loads the
standard C startup file from the usual place. See @file{gcc.c}.
+@end defmac
-@findex ENDFILE_SPEC
-@item ENDFILE_SPEC
+@defmac ENDFILE_SPEC
Another C string constant used much like @code{LINK_SPEC}. The
difference between the two is that @code{ENDFILE_SPEC} is used at
the very end of the command given to the linker.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex THREAD_MODEL_SPEC
-@item THREAD_MODEL_SPEC
+@defmac THREAD_MODEL_SPEC
GCC @code{-v} will print the thread model GCC was configured to use.
However, this doesn't work on platforms that are multilibbed on thread
models, such as AIX 4.3. On such platforms, define
blanks that names one of the recognized thread models. @code{%*}, the
default value of this macro, will expand to the value of
@code{thread_file} set in @file{config.gcc}.
+@end defmac
+
+@defmac SYSROOT_SUFFIX_SPEC
+Define this macro to add a suffix to the target sysroot when GCC is
+configured with a sysroot. This will cause GCC to search for usr/lib,
+et al, within sysroot+suffix.
+@end defmac
-@findex EXTRA_SPECS
-@item EXTRA_SPECS
+@defmac SYSROOT_HEADERS_SUFFIX_SPEC
+Define this macro to add a headers_suffix to the target sysroot when
+GCC is configured with a sysroot. This will cause GCC to pass the
+updated sysroot+headers_suffix to CPP@, causing it to search for
+usr/include, et al, within sysroot+headers_suffix.
+@end defmac
+
+@defmac EXTRA_SPECS
Define this macro to provide additional specifications to put in the
@file{specs} file that can be used in various specifications like
@code{CC1_SPEC}.
#undef CPP_SPEC
#define CPP_SPEC \
"%@{posix: -D_POSIX_SOURCE @} \
-%@{mcall-sysv: -D_CALL_SYSV @} %@{mcall-aix: -D_CALL_AIX @} \
-%@{!mcall-sysv: %@{!mcall-aix: %(cpp_sysv_default) @}@} \
+%@{mcall-sysv: -D_CALL_SYSV @} \
+%@{!mcall-sysv: %(cpp_sysv_default) @} \
%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}"
#undef CPP_SYSV_DEFAULT
#undef CPP_SYSV_DEFAULT
#define CPP_SYSV_DEFAULT "-D_CALL_AIX"
@end smallexample
+@end defmac
-@findex LINK_LIBGCC_SPECIAL
-@item LINK_LIBGCC_SPECIAL
+@defmac LINK_LIBGCC_SPECIAL
Define this macro if the driver program should find the library
@file{libgcc.a} itself and should not pass @option{-L} options to the
linker. If you do not define this macro, the driver program will pass
the argument @option{-lgcc} to tell the linker to do the search and will
pass @option{-L} options to it.
+@end defmac
-@findex LINK_LIBGCC_SPECIAL_1
-@item LINK_LIBGCC_SPECIAL_1
+@defmac LINK_LIBGCC_SPECIAL_1
Define this macro if the driver program should find the library
@file{libgcc.a}. If you do not define this macro, the driver program will pass
the argument @option{-lgcc} to tell the linker to do the search.
This macro is similar to @code{LINK_LIBGCC_SPECIAL}, except that it does
not affect @option{-L} options.
+@end defmac
-@findex LINK_GCC_C_SEQUENCE_SPEC
-@item LINK_GCC_C_SEQUENCE_SPEC
+@defmac LINK_GCC_C_SEQUENCE_SPEC
The sequence in which libgcc and libc are specified to the linker.
By default this is @code{%G %L %G}.
+@end defmac
-@findex LINK_COMMAND_SPEC
-@item LINK_COMMAND_SPEC
+@defmac LINK_COMMAND_SPEC
A C string constant giving the complete command line need to execute the
linker. When you do this, you will need to update your port each time a
change is made to the link command line within @file{gcc.c}. Therefore,
line for invoking the linker and there is no other way to accomplish
the effect you need. Overriding this macro may be avoidable by overriding
@code{LINK_GCC_C_SEQUENCE_SPEC} instead.
+@end defmac
-@findex LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
-@item LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
+@defmac LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
A nonzero value causes @command{collect2} to remove duplicate @option{-L@var{directory}} search
directories from linking commands. Do not give it a nonzero value if
removing duplicate search directories changes the linker's semantics.
+@end defmac
-@findex MULTILIB_DEFAULTS
-@item MULTILIB_DEFAULTS
+@defmac MULTILIB_DEFAULTS
Define this macro as a C expression for the initializer of an array of
string to tell the driver program which options are defaults for this
target and thus do not need to be handled specially when using
the target makefile fragment or if none of the options listed in
@code{MULTILIB_OPTIONS} are set by default.
@xref{Target Fragment}.
+@end defmac
-@findex RELATIVE_PREFIX_NOT_LINKDIR
-@item RELATIVE_PREFIX_NOT_LINKDIR
-Define this macro to tell @code{gcc} that it should only translate
+@defmac RELATIVE_PREFIX_NOT_LINKDIR
+Define this macro to tell @command{gcc} that it should only translate
a @option{-B} prefix into a @option{-L} linker option if the prefix
indicates an absolute file name.
+@end defmac
-@findex STANDARD_EXEC_PREFIX
-@item STANDARD_EXEC_PREFIX
+@defmac STANDARD_EXEC_PREFIX
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/local/lib/gcc-lib/} as the default prefix to
try when searching for the executable files of the compiler.
+@end defmac
-@findex MD_EXEC_PREFIX
-@item MD_EXEC_PREFIX
+@defmac MD_EXEC_PREFIX
If defined, this macro is an additional prefix to try after
@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched
when the @option{-b} option is used, or the compiler is built as a cross
compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it
to the list of directories used to find the assembler in @file{configure.in}.
+@end defmac
-@findex STANDARD_STARTFILE_PREFIX
-@item STANDARD_STARTFILE_PREFIX
+@defmac STANDARD_STARTFILE_PREFIX
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/local/lib/} as the default prefix to
try when searching for startup files such as @file{crt0.o}.
+@end defmac
-@findex MD_STARTFILE_PREFIX
-@item MD_STARTFILE_PREFIX
+@defmac MD_STARTFILE_PREFIX
If defined, this macro supplies an additional prefix to try after the
standard prefixes. @code{MD_EXEC_PREFIX} is not searched when the
@option{-b} option is used, or when the compiler is built as a cross
compiler.
+@end defmac
-@findex MD_STARTFILE_PREFIX_1
-@item MD_STARTFILE_PREFIX_1
+@defmac MD_STARTFILE_PREFIX_1
If defined, this macro supplies yet another prefix to try after the
standard prefixes. It is not searched when the @option{-b} option is
used, or when the compiler is built as a cross compiler.
+@end defmac
-@findex INIT_ENVIRONMENT
-@item INIT_ENVIRONMENT
+@defmac INIT_ENVIRONMENT
Define this macro as a C string constant if you wish to set environment
variables for programs called by the driver, such as the assembler and
loader. The driver passes the value of this macro to @code{putenv} to
initialize the necessary environment variables.
+@end defmac
-@findex LOCAL_INCLUDE_DIR
-@item LOCAL_INCLUDE_DIR
+@defmac LOCAL_INCLUDE_DIR
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/local/include} as the default prefix to
try when searching for local header files. @code{LOCAL_INCLUDE_DIR}
Cross compilers do not search either @file{/usr/local/include} or its
replacement.
+@end defmac
-@findex MODIFY_TARGET_NAME
-@item MODIFY_TARGET_NAME
-Define this macro if you with to define command-line switches that modify the
-default target name
+@defmac MODIFY_TARGET_NAME
+Define this macro if you wish to define command-line switches that
+modify the default target name.
For each switch, you can include a string to be appended to the first
part of the configuration name or a string to be deleted from the
@{ @{ "-32", DELETE, "64"@}, \
@{"-64", ADD, "64"@}@}
@end smallexample
+@end defmac
-
-@findex SYSTEM_INCLUDE_DIR
-@item SYSTEM_INCLUDE_DIR
+@defmac SYSTEM_INCLUDE_DIR
Define this macro as a C string constant if you wish to specify a
system-specific directory to search for header files before the standard
directory. @code{SYSTEM_INCLUDE_DIR} comes before
Cross compilers do not use this macro and do not search the directory
specified.
+@end defmac
-@findex STANDARD_INCLUDE_DIR
-@item STANDARD_INCLUDE_DIR
+@defmac STANDARD_INCLUDE_DIR
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/include} as the default prefix to
try when searching for header files.
-Cross compilers do not use this macro and do not search either
+Cross compilers ignore this macro and do not search either
@file{/usr/include} or its replacement.
+@end defmac
-@findex STANDARD_INCLUDE_COMPONENT
-@item STANDARD_INCLUDE_COMPONENT
+@defmac STANDARD_INCLUDE_COMPONENT
The ``component'' corresponding to @code{STANDARD_INCLUDE_DIR}.
See @code{INCLUDE_DEFAULTS}, below, for the description of components.
If you do not define this macro, no component is used.
+@end defmac
-@findex INCLUDE_DEFAULTS
-@item INCLUDE_DEFAULTS
+@defmac INCLUDE_DEFAULTS
Define this macro if you wish to override the entire default search path
for include files. For a native compiler, the default search path
usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR},
@{ 0, 0, 0, 0@} \
@}
@end example
-@end table
+@end defmac
Here is the order of prefixes tried for exec files:
@c prevent bad page break with this line
Here are run-time target specifications.
-@table @code
-@findex TARGET_CPU_CPP_BUILTINS
-@item TARGET_CPU_CPP_BUILTINS()
+@defmac TARGET_CPU_CPP_BUILTINS ()
This function-like macro expands to a block of code that defines
built-in preprocessor macros and assertions for the target cpu, using
the functions @code{builtin_define}, @code{builtin_define_std} and
-@code{builtin_assert} defined in @file{c-common.c}. When the front end
+@code{builtin_assert}. When the front end
calls this macro it provides a trailing semicolon, and since it has
finished command line option processing your code can use those
results freely.
assembler, this variable will be @code{clk_c} but the function-like
macro @code{preprocessing_asm_p()} will return true, so you might want
to check for that first. If you need to check for strict ANSI, the
-variable @code{flag_iso} can be used.
-
-With @code{TARGET_OS_CPP_BUILTINS} this macro obsoletes the
-@code{CPP_PREDEFINES} target macro.
+variable @code{flag_iso} can be used. The function-like macro
+@code{preprocessing_trad_p()} can be used to check for traditional
+preprocessing.
+@end defmac
-@findex TARGET_OS_CPP_BUILTINS
-@item TARGET_OS_CPP_BUILTINS()
+@defmac TARGET_OS_CPP_BUILTINS ()
Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
and is used for the target operating system instead.
+@end defmac
-With @code{TARGET_CPU_CPP_BUILTINS} this macro obsoletes the
-@code{CPP_PREDEFINES} target macro.
-
-@findex CPP_PREDEFINES
-@item CPP_PREDEFINES
-Define this to be a string constant containing @option{-D} options to
-define the predefined macros that identify this machine and system.
-These macros will be predefined unless the @option{-ansi} option (or a
-@option{-std} option for strict ISO C conformance) is specified.
-
-In addition, a parallel set of macros are predefined, whose names are
-made by appending @samp{__} at the beginning and at the end. These
-@samp{__} macros are permitted by the ISO standard, so they are
-predefined regardless of whether @option{-ansi} or a @option{-std} option
-is specified.
-
-For example, on the Sun, one can use the following value:
-
-@smallexample
-"-Dmc68000 -Dsun -Dunix"
-@end smallexample
-
-The result is to define the macros @code{__mc68000__}, @code{__sun__}
-and @code{__unix__} unconditionally, and the macros @code{mc68000},
-@code{sun} and @code{unix} provided @option{-ansi} is not specified.
+@defmac TARGET_OBJFMT_CPP_BUILTINS ()
+Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
+and is used for the target object format. @file{elfos.h} uses this
+macro to define @code{__ELF__}, so you probably do not need to define
+it yourself.
+@end defmac
-@findex extern int target_flags
-@item extern int target_flags;
+@deftypevar {extern int} target_flags
This declaration should be present.
+@end deftypevar
@cindex optional hardware or system features
@cindex features, optional, in system conventions
-@item TARGET_@dots{}
+
+@defmac TARGET_@var{featurename}
This series of macros is to allow compiler command arguments to
enable or disable the use of optional features of the target machine.
For example, one machine description serves both the 68000 and
Define a macro @code{TARGET_@var{featurename}} for each such option.
Its definition should test a bit in @code{target_flags}. It is
-recommended that a helper macro @code{TARGET_MASK_@var{featurename}}
+recommended that a helper macro @code{MASK_@var{featurename}}
is defined for each bit-value to test, and used in
@code{TARGET_@var{featurename}} and @code{TARGET_SWITCHES}. For
example:
@smallexample
#define TARGET_MASK_68020 1
-#define TARGET_68020 (target_flags & TARGET_MASK_68020)
+#define TARGET_68020 (target_flags & MASK_68020)
@end smallexample
One place where these macros are used is in the condition-expressions
frequently in the 68000 machine description file, @file{m68k.md}.
Another place they are used is in the definitions of the other
macros in the @file{@var{machine}.h} file.
+@end defmac
-@findex TARGET_SWITCHES
-@item TARGET_SWITCHES
+@defmac TARGET_SWITCHES
This macro defines names of command options to set and clear
bits in @code{target_flags}. Its definition is an initializer
with a subgrouping for each command option.
@smallexample
#define TARGET_SWITCHES \
- @{ @{ "68020", TARGET_MASK_68020, "" @}, \
- @{ "68000", -TARGET_MASK_68020, \
+ @{ @{ "68020", MASK_68020, "" @}, \
+ @{ "68000", -MASK_68020, \
N_("Compile for the 68000") @}, \
- @{ "", TARGET_MASK_68020, "" @}@}
+ @{ "", MASK_68020, "" @}, \
+ @}
@end smallexample
+@end defmac
-@findex TARGET_OPTIONS
-@item TARGET_OPTIONS
+@defmac TARGET_OPTIONS
This macro is similar to @code{TARGET_SWITCHES} but defines names of command
options that have values. Its definition is an initializer with a
subgrouping for each command option.
-Each subgrouping contains a string constant, that defines the fixed part
-of the option name, the address of a variable, and a description string.
-Non-empty description strings should be marked with @code{N_(@dots{})} for
-@command{xgettext}. Please do not mark empty strings because the empty
-string is reserved by GNU gettext. @code{gettext("")} returns the header entry
-of the message catalog with meta information, not the empty string.
+Each subgrouping contains a string constant, that defines the option
+name, the address of a variable, a description string, and a value.
+Non-empty description strings should be marked with @code{N_(@dots{})}
+for @command{xgettext}. Please do not mark empty strings because the
+empty string is reserved by GNU gettext. @code{gettext("")} returns the
+header entry of the message catalog with meta information, not the empty
+string.
+
+If the value listed in the table is @code{NULL}, then the variable, type
+@code{char *}, is set to the variable part of the given option if the
+fixed part matches. In other words, if the first part of the option
+matches what's in the table, the variable will be set to point to the
+rest of the option. This allows the user to specify a value for that
+option. The actual option name is made by appending @samp{-m} to the
+specified name. Again, each option should also be documented in
+@file{invoke.texi}.
-The variable, type @code{char *}, is set to the variable part of the
-given option if the fixed part matches. The actual option name is made
-by appending @samp{-m} to the specified name. Again, each option should
-also be documented in @file{invoke.texi}.
+If the value listed in the table is non-@code{NULL}, then the option
+must match the option in the table exactly (with @samp{-m}), and the
+variable is set to point to the value listed in the table.
Here is an example which defines @option{-mshort-data-@var{number}}. If the
given option is @option{-mshort-data-512}, the variable @code{m88k_short_data}
extern char *m88k_short_data;
#define TARGET_OPTIONS \
@{ @{ "short-data-", &m88k_short_data, \
- N_("Specify the size of the short data section") @} @}
+ N_("Specify the size of the short data section"), 0 @} @}
+@end smallexample
+
+Here is a variant of the above that allows the user to also specify
+just @option{-mshort-data} where a default of @code{"64"} is used.
+
+@smallexample
+extern char *m88k_short_data;
+#define TARGET_OPTIONS \
+ @{ @{ "short-data-", &m88k_short_data, \
+ N_("Specify the size of the short data section"), 0 @} \
+ @{ "short-data", &m88k_short_data, "", "64" @},
+ @}
@end smallexample
-@findex TARGET_VERSION
-@item TARGET_VERSION
+Here is an example which defines @option{-mno-alu}, @option{-malu1}, and
+@option{-malu2} as a three-state switch, along with suitable macros for
+checking the state of the option (documentation is elided for brevity).
+
+@smallexample
+[chip.c]
+char *chip_alu = ""; /* Specify default here. */
+
+[chip.h]
+extern char *chip_alu;
+#define TARGET_OPTIONS \
+ @{ @{ "no-alu", &chip_alu, "", "" @}, \
+ @{ "alu1", &chip_alu, "", "1" @}, \
+ @{ "alu2", &chip_alu, "", "2" @}, @}
+#define TARGET_ALU (chip_alu[0] != '\0')
+#define TARGET_ALU1 (chip_alu[0] == '1')
+#define TARGET_ALU2 (chip_alu[0] == '2')
+@end smallexample
+@end defmac
+
+@defmac TARGET_VERSION
This macro is a C statement to print on @code{stderr} a string
describing the particular machine description choice. Every machine
description should define @code{TARGET_VERSION}. For example:
fprintf (stderr, " (68k, MIT syntax)");
#endif
@end smallexample
+@end defmac
-@findex OVERRIDE_OPTIONS
-@item OVERRIDE_OPTIONS
+@defmac OVERRIDE_OPTIONS
Sometimes certain combinations of command options do not make sense on
a particular target machine. You can define a macro
@code{OVERRIDE_OPTIONS} to take account of this. This macro, if
Don't use this macro to turn on various extra optimizations for
@option{-O}. That is what @code{OPTIMIZATION_OPTIONS} is for.
+@end defmac
-@findex OPTIMIZATION_OPTIONS
-@item OPTIMIZATION_OPTIONS (@var{level}, @var{size})
+@defmac OPTIMIZATION_OPTIONS (@var{level}, @var{size})
Some machines may desire to change what optimizations are performed for
various optimization levels. This macro, if defined, is executed once
just after the optimization level is determined and before the remainder
@strong{Do not examine @code{write_symbols} in
this macro!} The debugging options are not supposed to alter the
generated code.
+@end defmac
-@findex CAN_DEBUG_WITHOUT_FP
-@item CAN_DEBUG_WITHOUT_FP
+@defmac CAN_DEBUG_WITHOUT_FP
Define this macro if debugging can be performed even without a frame
pointer. If this macro is defined, GCC will turn on the
@option{-fomit-frame-pointer} option whenever @option{-O} is specified.
-@end table
+@end defmac
@node Per-Function Data
@section Defining data structures for per-function information.
single data area approach is no longer used, these pointers are no
longer supported.
-The macro and function pointers are described below.
-
-@table @code
-@findex INIT_EXPANDERS
-@item INIT_EXPANDERS
+@defmac INIT_EXPANDERS
Macro called to initialize any target specific information. This macro
is called once per function, before generation of any RTL has begun.
The intention of this macro is to allow the initialization of the
-function pointers below.
+function pointer @code{init_machine_status}.
+@end defmac
-@findex init_machine_status
-@item init_machine_status
-This is a @code{void (*)(struct function *)} function pointer. If this
-pointer is non-@code{NULL} it will be called once per function, before function
-compilation starts, in order to allow the target to perform any target
-specific initialization of the @code{struct function} structure. It is
-intended that this would be used to initialize the @code{machine} of
-that structure.
+@deftypevar {void (*)(struct function *)} init_machine_status
+If this function pointer is non-@code{NULL} it will be called once per
+function, before function compilation starts, in order to allow the
+target to perform any target specific initialization of the
+@code{struct function} structure. It is intended that this would be
+used to initialize the @code{machine} of that structure.
@code{struct machine_function} structures are expected to be freed by GC.
Generally, any memory that they reference must be allocated by using
@code{ggc_alloc}, including the structure itself.
-
-@end table
+@end deftypevar
@node Storage Layout
@section Storage Layout
expressions that refer to static variables, such as the @code{target_flags}.
@xref{Run-time Target}.
-@table @code
-@findex BITS_BIG_ENDIAN
-@item BITS_BIG_ENDIAN
+@defmac BITS_BIG_ENDIAN
Define this macro to have the value 1 if the most significant bit in a
byte has the lowest number; otherwise define it to have the value zero.
This means that bit-field instructions count from the most significant
This macro does not affect the way structure fields are packed into
bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}.
+@end defmac
-@findex BYTES_BIG_ENDIAN
-@item BYTES_BIG_ENDIAN
+@defmac BYTES_BIG_ENDIAN
Define this macro to have the value 1 if the most significant byte in a
word has the lowest number. This macro need not be a constant.
+@end defmac
-@findex WORDS_BIG_ENDIAN
-@item WORDS_BIG_ENDIAN
+@defmac WORDS_BIG_ENDIAN
Define this macro to have the value 1 if, in a multiword object, the
most significant word has the lowest number. This applies to both
memory locations and registers; GCC fundamentally assumes that the
order of words in memory is the same as the order in registers. This
macro need not be a constant.
+@end defmac
-@findex LIBGCC2_WORDS_BIG_ENDIAN
-@item LIBGCC2_WORDS_BIG_ENDIAN
+@defmac LIBGCC2_WORDS_BIG_ENDIAN
Define this macro if @code{WORDS_BIG_ENDIAN} is not constant. This must be a
constant value with the same meaning as @code{WORDS_BIG_ENDIAN}, which will be
used only when compiling @file{libgcc2.c}. Typically the value will be set
based on preprocessor defines.
+@end defmac
-@findex FLOAT_WORDS_BIG_ENDIAN
-@item FLOAT_WORDS_BIG_ENDIAN
+@defmac FLOAT_WORDS_BIG_ENDIAN
Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or
@code{TFmode} floating point numbers are stored in memory with the word
containing the sign bit at the lowest address; otherwise define it to
You need not define this macro if the ordering is the same as for
multi-word integers.
+@end defmac
-@findex BITS_PER_UNIT
-@item BITS_PER_UNIT
+@defmac BITS_PER_UNIT
Define this macro to be the number of bits in an addressable storage
unit (byte). If you do not define this macro the default is 8.
+@end defmac
-@findex BITS_PER_WORD
-@item BITS_PER_WORD
+@defmac BITS_PER_WORD
Number of bits in a word. If you do not define this macro, the default
is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
+@end defmac
-@findex MAX_BITS_PER_WORD
-@item MAX_BITS_PER_WORD
+@defmac MAX_BITS_PER_WORD
Maximum number of bits in a word. If this is undefined, the default is
@code{BITS_PER_WORD}. Otherwise, it is the constant value that is the
largest value that @code{BITS_PER_WORD} can have at run-time.
+@end defmac
-@findex UNITS_PER_WORD
-@item UNITS_PER_WORD
+@defmac UNITS_PER_WORD
Number of storage units in a word; normally 4.
+@end defmac
-@findex MIN_UNITS_PER_WORD
-@item MIN_UNITS_PER_WORD
+@defmac MIN_UNITS_PER_WORD
Minimum number of units in a word. If this is undefined, the default is
@code{UNITS_PER_WORD}. Otherwise, it is the constant value that is the
smallest value that @code{UNITS_PER_WORD} can have at run-time.
+@end defmac
-@findex POINTER_SIZE
-@item POINTER_SIZE
+@defmac POINTER_SIZE
Width of a pointer, in bits. You must specify a value no wider than the
width of @code{Pmode}. If it is not equal to the width of @code{Pmode},
you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify
a value the default is @code{BITS_PER_WORD}.
+@end defmac
-@findex POINTERS_EXTEND_UNSIGNED
-@item POINTERS_EXTEND_UNSIGNED
+@defmac POINTERS_EXTEND_UNSIGNED
A C expression whose value is greater than zero if pointers that need to be
extended from being @code{POINTER_SIZE} bits wide to @code{Pmode} are to
be zero-extended and zero if they are to be sign-extended. If the value
You need not define this macro if the @code{POINTER_SIZE} is equal
to the width of @code{Pmode}.
+@end defmac
-@findex PROMOTE_MODE
-@item PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
+@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
A macro to update @var{m} and @var{unsignedp} when an object whose type
is @var{type} and which has the specified mode and signedness is to be
stored in a register. This macro is only called when @var{type} is a
@var{unsignedp} according to which kind of extension is more efficient.
Do not define this macro if it would never modify @var{m}.
+@end defmac
-@findex PROMOTE_FUNCTION_ARGS
-@item PROMOTE_FUNCTION_ARGS
+@defmac PROMOTE_FUNCTION_ARGS
Define this macro if the promotion described by @code{PROMOTE_MODE}
should also be done for outgoing function arguments.
+@end defmac
-@findex PROMOTE_FUNCTION_RETURN
-@item PROMOTE_FUNCTION_RETURN
+@defmac PROMOTE_FUNCTION_RETURN
Define this macro if the promotion described by @code{PROMOTE_MODE}
should also be done for the return value of functions.
If this macro is defined, @code{FUNCTION_VALUE} must perform the same
promotions done by @code{PROMOTE_MODE}.
+@end defmac
-@findex PROMOTE_FOR_CALL_ONLY
-@item PROMOTE_FOR_CALL_ONLY
+@defmac PROMOTE_FOR_CALL_ONLY
Define this macro if the promotion described by @code{PROMOTE_MODE}
should @emph{only} be performed for outgoing function arguments or
function return values, as specified by @code{PROMOTE_FUNCTION_ARGS}
and @code{PROMOTE_FUNCTION_RETURN}, respectively.
+@end defmac
-@findex PARM_BOUNDARY
-@item PARM_BOUNDARY
+@defmac PARM_BOUNDARY
Normal alignment required for function parameters on the stack, in
bits. All stack parameters receive at least this much alignment
regardless of data type. On most machines, this is the same as the
size of an integer.
+@end defmac
-@findex STACK_BOUNDARY
-@item STACK_BOUNDARY
+@defmac STACK_BOUNDARY
Define this macro to the minimum alignment enforced by hardware for the
stack pointer on this machine. The definition is a C expression for the
desired alignment (measured in bits). This value is used as a default
if @code{PREFERRED_STACK_BOUNDARY} is not defined. On most machines,
this should be the same as @code{PARM_BOUNDARY}.
+@end defmac
-@findex PREFERRED_STACK_BOUNDARY
-@item PREFERRED_STACK_BOUNDARY
+@defmac PREFERRED_STACK_BOUNDARY
Define this macro if you wish to preserve a certain alignment for the
stack pointer, greater than what the hardware enforces. The definition
is a C expression for the desired alignment (measured in bits). This
macro must evaluate to a value equal to or larger than
@code{STACK_BOUNDARY}.
+@end defmac
-@findex FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
-@item FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
+@defmac FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
A C expression that evaluates true if @code{PREFERRED_STACK_BOUNDARY} is
not guaranteed by the runtime and we should emit code to align the stack
at the beginning of @code{main}.
to the specified boundary. If @code{PUSH_ROUNDING} is defined and specifies
a less strict alignment than @code{PREFERRED_STACK_BOUNDARY}, the stack may
be momentarily unaligned while pushing arguments.
+@end defmac
-@findex FUNCTION_BOUNDARY
-@item FUNCTION_BOUNDARY
+@defmac FUNCTION_BOUNDARY
Alignment required for a function entry point, in bits.
+@end defmac
-@findex BIGGEST_ALIGNMENT
-@item BIGGEST_ALIGNMENT
+@defmac BIGGEST_ALIGNMENT
Biggest alignment that any data type can require on this machine, in bits.
+@end defmac
-@findex MINIMUM_ATOMIC_ALIGNMENT
-@item MINIMUM_ATOMIC_ALIGNMENT
+@defmac MINIMUM_ATOMIC_ALIGNMENT
If defined, the smallest alignment, in bits, that can be given to an
object that can be referenced in one operation, without disturbing any
nearby object. Normally, this is @code{BITS_PER_UNIT}, but may be larger
on machines that don't have byte or half-word store operations.
+@end defmac
-@findex BIGGEST_FIELD_ALIGNMENT
-@item BIGGEST_FIELD_ALIGNMENT
+@defmac BIGGEST_FIELD_ALIGNMENT
Biggest alignment that any structure or union field can require on this
machine, in bits. If defined, this overrides @code{BIGGEST_ALIGNMENT} for
structure and union fields only, unless the field alignment has been set
by the @code{__attribute__ ((aligned (@var{n})))} construct.
+@end defmac
-@findex ADJUST_FIELD_ALIGN
-@item ADJUST_FIELD_ALIGN (@var{field}, @var{computed})
+@defmac ADJUST_FIELD_ALIGN (@var{field}, @var{computed})
An expression for the alignment of a structure field @var{field} if the
alignment computed in the usual way (including applying of
@code{BIGGEST_ALIGNMENT} and @code{BIGGEST_FIELD_ALIGNMENT} to the
alignment) is @var{computed}. It overrides alignment only if the
field alignment has not been set by the
@code{__attribute__ ((aligned (@var{n})))} construct.
+@end defmac
-@findex MAX_OFILE_ALIGNMENT
-@item MAX_OFILE_ALIGNMENT
+@defmac MAX_OFILE_ALIGNMENT
Biggest alignment supported by the object file format of this machine.
Use this macro to limit the alignment which can be specified using the
@code{__attribute__ ((aligned (@var{n})))} construct. If not defined,
the default value is @code{BIGGEST_ALIGNMENT}.
+@end defmac
-@findex DATA_ALIGNMENT
-@item DATA_ALIGNMENT (@var{type}, @var{basic-align})
+@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align})
If defined, a C expression to compute the alignment for a variable in
the static store. @var{type} is the data type, and @var{basic-align} is
the alignment that the object would ordinarily have. The value of this
make it all fit in fewer cache lines. Another is to cause character
arrays to be word-aligned so that @code{strcpy} calls that copy
constants to character arrays can be done inline.
+@end defmac
-@findex CONSTANT_ALIGNMENT
-@item CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
+@defmac CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
If defined, a C expression to compute the alignment given to a constant
that is being placed in memory. @var{constant} is the constant and
@var{basic-align} is the alignment that the object would ordinarily
The typical use of this macro is to increase alignment for string
constants to be word aligned so that @code{strcpy} calls that copy
constants can be done inline.
+@end defmac
-@findex LOCAL_ALIGNMENT
-@item LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
+@defmac LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
If defined, a C expression to compute the alignment for a variable in
the local store. @var{type} is the data type, and @var{basic-align} is
the alignment that the object would ordinarily have. The value of this
One use of this macro is to increase alignment of medium-size data to
make it all fit in fewer cache lines.
+@end defmac
-@findex EMPTY_FIELD_BOUNDARY
-@item EMPTY_FIELD_BOUNDARY
+@defmac EMPTY_FIELD_BOUNDARY
Alignment in bits to be given to a structure bit-field that follows an
empty field such as @code{int : 0;}.
-Note that @code{PCC_BITFIELD_TYPE_MATTERS} also affects the alignment
-that results from an empty field.
+If @code{PCC_BITFIELD_TYPE_MATTERS} is true, it overrides this macro.
+@end defmac
-@findex STRUCTURE_SIZE_BOUNDARY
-@item STRUCTURE_SIZE_BOUNDARY
+@defmac STRUCTURE_SIZE_BOUNDARY
Number of bits which any structure or union's size must be a multiple of.
Each structure or union's size is rounded up to a multiple of this.
If you do not define this macro, the default is the same as
@code{BITS_PER_UNIT}.
+@end defmac
-@findex STRICT_ALIGNMENT
-@item STRICT_ALIGNMENT
+@defmac STRICT_ALIGNMENT
Define this macro to be the value 1 if instructions will fail to work
if given data not on the nominal alignment. If instructions will merely
go slower in that case, define this macro as 0.
+@end defmac
-@findex PCC_BITFIELD_TYPE_MATTERS
-@item PCC_BITFIELD_TYPE_MATTERS
+@defmac PCC_BITFIELD_TYPE_MATTERS
Define this if you wish to imitate the way many other C compilers handle
alignment of bit-fields and the structures that contain them.
-The behavior is that the type written for a bit-field (@code{int},
-@code{short}, or other integer type) imposes an alignment for the
-entire structure, as if the structure really did contain an ordinary
-field of that type. In addition, the bit-field is placed within the
-structure so that it would fit within such a field, not crossing a
-boundary for it.
+The behavior is that the type written for a named bit-field (@code{int},
+@code{short}, or other integer type) imposes an alignment for the entire
+structure, as if the structure really did contain an ordinary field of
+that type. In addition, the bit-field is placed within the structure so
+that it would fit within such a field, not crossing a boundary for it.
-Thus, on most machines, a bit-field whose type is written as @code{int}
-would not cross a four-byte boundary, and would force four-byte
-alignment for the whole structure. (The alignment used may not be four
-bytes; it is controlled by the other alignment parameters.)
+Thus, on most machines, a named bit-field whose type is written as
+@code{int} would not cross a four-byte boundary, and would force
+four-byte alignment for the whole structure. (The alignment used may
+not be four bytes; it is controlled by the other alignment parameters.)
+
+An unnamed bit-field will not affect the alignment of the containing
+structure.
If the macro is defined, its definition should be a C expression;
a nonzero value for the expression enables this behavior.
If this prints 2 and 5, then the compiler's behavior is what you would
get from @code{PCC_BITFIELD_TYPE_MATTERS}.
+@end defmac
-@findex BITFIELD_NBYTES_LIMITED
-@item BITFIELD_NBYTES_LIMITED
+@defmac BITFIELD_NBYTES_LIMITED
Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited
to aligning a bit-field within the structure.
+@end defmac
-@findex MEMBER_TYPE_FORCES_BLK
-@item MEMBER_TYPE_FORCES_BLK (@var{field}, @var{mode})
+@defmac MEMBER_TYPE_FORCES_BLK (@var{field}, @var{mode})
Return 1 if a structure or array containing @var{field} should be accessed using
@code{BLKMODE}.
Normally, this is not needed. See the file @file{c4x.h} for an example
of how to use this macro to prevent a structure having a floating point
field from being accessed in an integer mode.
+@end defmac
-@findex ROUND_TYPE_SIZE
-@item ROUND_TYPE_SIZE (@var{type}, @var{computed}, @var{specified})
-Define this macro as an expression for the overall size of a type
-(given by @var{type} as a tree node) when the size computed in the
-usual way is @var{computed} and the alignment is @var{specified}.
-
-The default is to round @var{computed} up to a multiple of @var{specified}.
-
-@findex ROUND_TYPE_SIZE_UNIT
-@item ROUND_TYPE_SIZE_UNIT (@var{type}, @var{computed}, @var{specified})
-Similar to @code{ROUND_TYPE_SIZE}, but sizes and alignments are
-specified in units (bytes). If you define @code{ROUND_TYPE_SIZE},
-you must also define this macro and they must be defined consistently
-with each other.
-
-@findex ROUND_TYPE_ALIGN
-@item ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
+@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
Define this macro as an expression for the alignment of a type (given
by @var{type} as a tree node) if the alignment computed in the usual
way is @var{computed} and the alignment explicitly specified was
The default is to use @var{specified} if it is larger; otherwise, use
the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT}
+@end defmac
-@findex MAX_FIXED_MODE_SIZE
-@item MAX_FIXED_MODE_SIZE
+@defmac MAX_FIXED_MODE_SIZE
An integer expression for the size in bits of the largest integer
machine mode that should actually be used. All integer machine modes of
this size or smaller can be used for structures and unions with the
appropriate sizes. If this macro is undefined, @code{GET_MODE_BITSIZE
(DImode)} is assumed.
+@end defmac
-@findex VECTOR_MODE_SUPPORTED_P
-@item VECTOR_MODE_SUPPORTED_P(@var{mode})
+@defmac VECTOR_MODE_SUPPORTED_P (@var{mode})
Define this macro to be nonzero if the port is prepared to handle insns
involving vector mode @var{mode}. At the very least, it must have move
patterns for this mode.
+@end defmac
-@findex STACK_SAVEAREA_MODE
-@item STACK_SAVEAREA_MODE (@var{save_level})
+@defmac STACK_SAVEAREA_MODE (@var{save_level})
If defined, an expression of type @code{enum machine_mode} that
specifies the mode of the save area operand of a
@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
would most commonly define this macro if the
@code{save_stack_@var{level}} patterns need to support both a 32- and a
64-bit mode.
+@end defmac
-@findex STACK_SIZE_MODE
-@item STACK_SIZE_MODE
+@defmac STACK_SIZE_MODE
If defined, an expression of type @code{enum machine_mode} that
specifies the mode of the size increment operand of an
@code{allocate_stack} named pattern (@pxref{Standard Names}).
You need not define this macro if it always returns @code{word_mode}.
You would most commonly define this macro if the @code{allocate_stack}
pattern needs to support both a 32- and a 64-bit mode.
+@end defmac
-@findex CHECK_FLOAT_VALUE
-@item CHECK_FLOAT_VALUE (@var{mode}, @var{value}, @var{overflow})
-A C statement to validate the value @var{value} (of type
-@code{double}) for mode @var{mode}. This means that you check whether
-@var{value} fits within the possible range of values for mode
-@var{mode} on this target machine. The mode @var{mode} is always
-a mode of class @code{MODE_FLOAT}. @var{overflow} is nonzero if
-the value is already known to be out of range.
-
-If @var{value} is not valid or if @var{overflow} is nonzero, you should
-set @var{overflow} to 1 and then assign some valid value to @var{value}.
-Allowing an invalid value to go through the compiler can produce
-incorrect assembler code which may even cause Unix assemblers to crash.
-
-This macro need not be defined if there is no work for it to do.
-
-@findex TARGET_FLOAT_FORMAT
-@item TARGET_FLOAT_FORMAT
+@defmac TARGET_FLOAT_FORMAT
A code distinguishing the floating point format of the target machine.
-There are five defined values:
+There are four defined values:
-@table @code
-@findex IEEE_FLOAT_FORMAT
+@ftable @code
@item IEEE_FLOAT_FORMAT
This code indicates IEEE floating point. It is the default; there is no
-need to define this macro when the format is IEEE@.
+need to define @code{TARGET_FLOAT_FORMAT} when the format is IEEE@.
-@findex VAX_FLOAT_FORMAT
@item VAX_FLOAT_FORMAT
This code indicates the ``F float'' (for @code{float}) and ``D float''
or ``G float'' formats (for @code{double}) used on the VAX and PDP-11@.
-@findex IBM_FLOAT_FORMAT
@item IBM_FLOAT_FORMAT
This code indicates the format used on the IBM System/370.
-@findex C4X_FLOAT_FORMAT
@item C4X_FLOAT_FORMAT
This code indicates the format used on the TMS320C3x/C4x.
+@end ftable
-@findex UNKNOWN_FLOAT_FORMAT
-@item UNKNOWN_FLOAT_FORMAT
-This code indicates any other format.
-@end table
-
-If any other
-formats are actually in use on supported machines, new codes should be
-defined for them.
+If your target uses a floating point format other than these, you must
+define a new @var{name}_FLOAT_FORMAT code for it, and add support for
+it to @file{real.c}.
The ordering of the component words of floating point values stored in
memory is controlled by @code{FLOAT_WORDS_BIG_ENDIAN}.
+@end defmac
-@findex VAX_HALFWORD_ORDER
-@item VAX_HALFWORD_ORDER
-This macro is only used if @code{TARGET_FLOAT_FORMAT} is
-@code{VAX_FLOAT_FORMAT}. If defaulted or defined as 1, the halfwords of
-the generated floating point data are in the order used by the VAX. If
-defined as 0, they are reversed, which is used by the PDP-11 target.
-
-@findex MODE_HAS_NANS
-@item MODE_HAS_NANS (@var{mode})
+@defmac MODE_HAS_NANS (@var{mode})
When defined, this macro should be true if @var{mode} has a NaN
representation. The compiler assumes that NaNs are not equal to
anything (including themselves) and that addition, subtraction,
By default, this macro is true if @var{mode} is a floating-point
mode and the target floating-point format is IEEE@.
+@end defmac
-@findex MODE_HAS_INFINITIES
-@item MODE_HAS_INFINITIES (@var{mode})
+@defmac MODE_HAS_INFINITIES (@var{mode})
This macro should be true if @var{mode} can represent infinity. At
present, the compiler uses this macro to decide whether @samp{x - x}
is always defined. By default, the macro is true when @var{mode}
is a floating-point mode and the target format is IEEE@.
+@end defmac
-@findex MODE_HAS_SIGNED_ZEROS
-@item MODE_HAS_SIGNED_ZEROS (@var{mode})
+@defmac MODE_HAS_SIGNED_ZEROS (@var{mode})
True if @var{mode} distinguishes between positive and negative zero.
The rules are expected to follow the IEEE standard:
The default definition is true if @var{mode} is a floating-point
mode and the target format is IEEE@.
+@end defmac
-@findex MODE_HAS_SIGN_DEPENDENT_ROUNDING
-@item MODE_HAS_SIGN_DEPENDENT_ROUNDING (@var{mode})
+@defmac MODE_HAS_SIGN_DEPENDENT_ROUNDING (@var{mode})
If defined, this macro should be true for @var{mode} if it has at
least one rounding mode in which @samp{x} and @samp{-x} can be
rounded to numbers of different magnitude. Two such modes are
The default definition of this macro is true if @var{mode} is
a floating-point mode and the target format is IEEE@.
+@end defmac
-@findex ROUND_TOWARDS_ZERO
-@item ROUND_TOWARDS_ZERO
+@defmac ROUND_TOWARDS_ZERO
If defined, this macro should be true if the prevailing rounding
mode is towards zero. A true value has the following effects:
parser should behave like the target's @code{strtod} where possible.
Not defining this macro is equivalent to returning zero.
+@end defmac
-@findex LARGEST_EXPONENT_IS_NORMAL
-@item LARGEST_EXPONENT_IS_NORMAL (@var{size})
+@defmac LARGEST_EXPONENT_IS_NORMAL (@var{size})
This macro should return true if floats with @var{size}
bits do not have a NaN or infinity representation, but use the largest
exponent for normal numbers instead.
floating-point arithmetic.
The default definition of this macro returns false for all sizes.
-@end table
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_VECTOR_OPAQUE_P (tree @var{type})
+This target hook should return @code{true} a vector is opaque. That
+is, if no cast is needed when copying a vector value of type
+@var{type} into another vector lvalue of the same size. Vector opaque
+types cannot be initialized. The default is that there are no such
+types.
+@end deftypefn
@deftypefn {Target Hook} bool TARGET_MS_BITFIELD_LAYOUT_P (tree @var{record_type})
This target hook returns @code{true} if bit-fields in the given
bit-field; (ii) a zero-sized bit-field will affect the alignment of
the whole enclosing structure, even if it is unnamed; except that
(iii) a zero-sized bit-field will be disregarded unless it follows
-another bit-field of non-zero size. If this hook returns @code{true},
+another bit-field of nonzero size. If this hook returns @code{true},
other macros that control bit-field layout are ignored.
+
+When a bit-field is inserted into a packed record, the whole size
+of the underlying type is used by one or more same-size adjacent
+bit-fields (that is, if its long:3, 32 bits is used in the record,
+and any additional adjacent long bit-fields are packed into the same
+chunk of 32 bits. However, if the size changes, a new field of that
+size is allocated). In an unpacked record, this is the same as using
+alignment, but not equivalent when packing.
+
+If both MS bit-fields and @samp{__attribute__((packed))} are used,
+the latter will take precedence. If @samp{__attribute__((packed))} is
+used on a single field when MS bit-fields are in use, it will take
+precedence for that field, but the alignment of the rest of the structure
+may affect its placement.
@end deftypefn
@node Type Layout
the previous section, these apply to specific features of C and related
languages, rather than to fundamental aspects of storage layout.
-@table @code
-@findex INT_TYPE_SIZE
-@item INT_TYPE_SIZE
+@defmac INT_TYPE_SIZE
A C expression for the size in bits of the type @code{int} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex SHORT_TYPE_SIZE
-@item SHORT_TYPE_SIZE
+@defmac SHORT_TYPE_SIZE
A C expression for the size in bits of the type @code{short} on the
target machine. If you don't define this, the default is half a word.
(If this would be less than one storage unit, it is rounded up to one
unit.)
+@end defmac
-@findex LONG_TYPE_SIZE
-@item LONG_TYPE_SIZE
+@defmac LONG_TYPE_SIZE
A C expression for the size in bits of the type @code{long} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex ADA_LONG_TYPE_SIZE
-@item ADA_LONG_TYPE_SIZE
+@defmac ADA_LONG_TYPE_SIZE
On some machines, the size used for the Ada equivalent of the type
@code{long} by a native Ada compiler differs from that used by C. In
that situation, define this macro to be a C expression to be used for
the size of that type. If you don't define this, the default is the
value of @code{LONG_TYPE_SIZE}.
+@end defmac
-@findex MAX_LONG_TYPE_SIZE
-@item MAX_LONG_TYPE_SIZE
+@defmac MAX_LONG_TYPE_SIZE
Maximum number for the size in bits of the type @code{long} on the
target machine. If this is undefined, the default is
@code{LONG_TYPE_SIZE}. Otherwise, it is the constant value that is the
largest value that @code{LONG_TYPE_SIZE} can have at run-time. This is
used in @code{cpp}.
+@end defmac
-@findex LONG_LONG_TYPE_SIZE
-@item LONG_LONG_TYPE_SIZE
+@defmac LONG_LONG_TYPE_SIZE
A C expression for the size in bits of the type @code{long long} on the
target machine. If you don't define this, the default is two
words. If you want to support GNU Ada on your machine, the value of this
macro must be at least 64.
+@end defmac
-@findex CHAR_TYPE_SIZE
-@item CHAR_TYPE_SIZE
+@defmac CHAR_TYPE_SIZE
A C expression for the size in bits of the type @code{char} on the
target machine. If you don't define this, the default is
@code{BITS_PER_UNIT}.
+@end defmac
-@findex BOOL_TYPE_SIZE
-@item BOOL_TYPE_SIZE
+@defmac BOOL_TYPE_SIZE
A C expression for the size in bits of the C++ type @code{bool} and
C99 type @code{_Bool} on the target machine. If you don't define
this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}.
+@end defmac
-@findex FLOAT_TYPE_SIZE
-@item FLOAT_TYPE_SIZE
+@defmac FLOAT_TYPE_SIZE
A C expression for the size in bits of the type @code{float} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex DOUBLE_TYPE_SIZE
-@item DOUBLE_TYPE_SIZE
+@defmac DOUBLE_TYPE_SIZE
A C expression for the size in bits of the type @code{double} on the
target machine. If you don't define this, the default is two
words.
+@end defmac
-@findex LONG_DOUBLE_TYPE_SIZE
-@item LONG_DOUBLE_TYPE_SIZE
+@defmac LONG_DOUBLE_TYPE_SIZE
A C expression for the size in bits of the type @code{long double} on
the target machine. If you don't define this, the default is two
words.
+@end defmac
-@findex MAX_LONG_DOUBLE_TYPE_SIZE
+@defmac MAX_LONG_DOUBLE_TYPE_SIZE
Maximum number for the size in bits of the type @code{long double} on the
target machine. If this is undefined, the default is
@code{LONG_DOUBLE_TYPE_SIZE}. Otherwise, it is the constant value that is
the largest value that @code{LONG_DOUBLE_TYPE_SIZE} can have at run-time.
This is used in @code{cpp}.
+@end defmac
-@findex INTEL_EXTENDED_IEEE_FORMAT
-@item INTEL_EXTENDED_IEEE_FORMAT
-Define this macro to be 1 if the target machine uses 80-bit floating-point
-values with 128-bit size and alignment. This is used in @file{real.c}.
-This also distinguishes the Intel 80-bit floating-point format from the
-Motorola 96-bit floating-point format.
-
-@findex TARGET_FLT_EVAL_METHOD
-@item TARGET_FLT_EVAL_METHOD
+@defmac TARGET_FLT_EVAL_METHOD
A C expression for the value for @code{FLT_EVAL_METHOD} in @file{float.h},
assuming, if applicable, that the floating-point control word is in its
default state. If you do not define this macro the value of
@code{FLT_EVAL_METHOD} will be zero.
+@end defmac
-@findex WIDEST_HARDWARE_FP_SIZE
-@item WIDEST_HARDWARE_FP_SIZE
+@defmac WIDEST_HARDWARE_FP_SIZE
A C expression for the size in bits of the widest floating-point format
supported by the hardware. If you define this macro, you must specify a
value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}.
If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE}
is the default.
+@end defmac
-@findex DEFAULT_SIGNED_CHAR
-@item DEFAULT_SIGNED_CHAR
+@defmac DEFAULT_SIGNED_CHAR
An expression whose value is 1 or 0, according to whether the type
@code{char} should be signed or unsigned by default. The user can
always override this default with the options @option{-fsigned-char}
and @option{-funsigned-char}.
+@end defmac
-@findex DEFAULT_SHORT_ENUMS
-@item DEFAULT_SHORT_ENUMS
+@defmac DEFAULT_SHORT_ENUMS
A C expression to determine whether to give an @code{enum} type
only as many bytes as it takes to represent the range of possible values
of that type. A nonzero value means to do that; a zero value means all
@code{enum} types should be allocated like @code{int}.
If you don't define the macro, the default is 0.
+@end defmac
-@findex SIZE_TYPE
-@item SIZE_TYPE
+@defmac SIZE_TYPE
A C expression for a string describing the name of the data type to use
for size values. The typedef name @code{size_t} is defined using the
contents of the string.
If you don't define this macro, the default is @code{"long unsigned
int"}.
+@end defmac
-@findex PTRDIFF_TYPE
-@item PTRDIFF_TYPE
+@defmac PTRDIFF_TYPE
A C expression for a string describing the name of the data type to use
for the result of subtracting two pointers. The typedef name
@code{ptrdiff_t} is defined using the contents of the string. See
@code{SIZE_TYPE} above for more information.
If you don't define this macro, the default is @code{"long int"}.
+@end defmac
-@findex WCHAR_TYPE
-@item WCHAR_TYPE
+@defmac WCHAR_TYPE
A C expression for a string describing the name of the data type to use
for wide characters. The typedef name @code{wchar_t} is defined using
the contents of the string. See @code{SIZE_TYPE} above for more
information.
If you don't define this macro, the default is @code{"int"}.
+@end defmac
-@findex WCHAR_TYPE_SIZE
-@item WCHAR_TYPE_SIZE
+@defmac WCHAR_TYPE_SIZE
A C expression for the size in bits of the data type for wide
characters. This is used in @code{cpp}, which cannot make use of
@code{WCHAR_TYPE}.
+@end defmac
-@findex MAX_WCHAR_TYPE_SIZE
-@item MAX_WCHAR_TYPE_SIZE
+@defmac MAX_WCHAR_TYPE_SIZE
Maximum number for the size in bits of the data type for wide
characters. If this is undefined, the default is
@code{WCHAR_TYPE_SIZE}. Otherwise, it is the constant value that is the
largest value that @code{WCHAR_TYPE_SIZE} can have at run-time. This is
used in @code{cpp}.
+@end defmac
-@findex GCOV_TYPE_SIZE
-@item GCOV_TYPE_SIZE
+@defmac GCOV_TYPE_SIZE
A C expression for the size in bits of the type used for gcov counters on the
target machine. If you don't define this, the default is one
@code{LONG_TYPE_SIZE} in case it is greater or equal to 64-bit and
@code{LONG_LONG_TYPE_SIZE} otherwise. You may want to re-define the type to
ensure atomicity for counters in multithreaded programs.
+@end defmac
-@findex WINT_TYPE
-@item WINT_TYPE
+@defmac WINT_TYPE
A C expression for a string describing the name of the data type to
use for wide characters passed to @code{printf} and returned from
@code{getwc}. The typedef name @code{wint_t} is defined using the
information.
If you don't define this macro, the default is @code{"unsigned int"}.
+@end defmac
-@findex INTMAX_TYPE
-@item INTMAX_TYPE
+@defmac INTMAX_TYPE
A C expression for a string describing the name of the data type that
can represent any value of any standard or extended signed integer type.
The typedef name @code{intmax_t} is defined using the contents of the
If you don't define this macro, the default is the first of
@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as
much precision as @code{long long int}.
+@end defmac
-@findex UINTMAX_TYPE
-@item UINTMAX_TYPE
+@defmac UINTMAX_TYPE
A C expression for a string describing the name of the data type that
can represent any value of any standard or extended unsigned integer
type. The typedef name @code{uintmax_t} is defined using the contents
@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long
unsigned int"} that has as much precision as @code{long long unsigned
int}.
+@end defmac
-@findex TARGET_PTRMEMFUNC_VBIT_LOCATION
-@item TARGET_PTRMEMFUNC_VBIT_LOCATION
+@defmac TARGET_PTRMEMFUNC_VBIT_LOCATION
The C++ compiler represents a pointer-to-member-function with a struct
that looks like:
in which function addresses are always even, according to
@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to
@code{ptrmemfunc_vbit_in_pfn}.
+@end defmac
-@findex TARGET_VTABLE_USES_DESCRIPTORS
-@item TARGET_VTABLE_USES_DESCRIPTORS
+@defmac TARGET_VTABLE_USES_DESCRIPTORS
Normally, the C++ compiler uses function pointers in vtables. This
macro allows the target to change to use ``function descriptors''
instead. Function descriptors are found on targets for whom a
If vtables are used, the value of this macro should be the number
of words that the function descriptor occupies.
+@end defmac
-@findex TARGET_VTABLE_ENTRY_ALIGN
-@item TARGET_VTABLE_ENTRY_ALIGN
+@defmac TARGET_VTABLE_ENTRY_ALIGN
By default, the vtable entries are void pointers, the so the alignment
is the same as pointer alignment. The value of this macro specifies
the alignment of the vtable entry in bits. It should be defined only
when special alignment is necessary. */
+@end defmac
-@findex TARGET_VTABLE_DATA_ENTRY_DISTANCE
-@item TARGET_VTABLE_DATA_ENTRY_DISTANCE
+@defmac TARGET_VTABLE_DATA_ENTRY_DISTANCE
There are a few non-descriptor entries in the vtable at offsets below
zero. If these entries must be padded (say, to preserve the alignment
specified by @code{TARGET_VTABLE_ENTRY_ALIGN}), set this to the number
of words in each data entry.
-@end table
+@end defmac
@node Escape Sequences
@section Target Character Escape Sequences
By default, GCC assumes that the C character escape sequences take on
their ASCII values for the target. If this is not correct, you must
-explicitly define all of the macros below.
+explicitly define all of the macros below. All of them must evaluate
+to constants; they are used in @code{case} statements.
-@table @code
@findex TARGET_BELL
-@item TARGET_BELL
-A C constant expression for the integer value for escape sequence
-@samp{\a}.
-
+@findex TARGET_CR
@findex TARGET_ESC
-@item TARGET_ESC
-A C constant expression for the integer value of the target escape
-character. As an extension, GCC evaluates the escape sequences
-@samp{\e} and @samp{\E} to this.
-
-@findex TARGET_TAB
-@findex TARGET_BS
+@findex TARGET_FF
@findex TARGET_NEWLINE
-@item TARGET_BS
-@itemx TARGET_TAB
-@itemx TARGET_NEWLINE
-C constant expressions for the integer values for escape sequences
-@samp{\b}, @samp{\t} and @samp{\n}.
-
+@findex TARGET_TAB
@findex TARGET_VT
-@findex TARGET_FF
-@findex TARGET_CR
-@item TARGET_VT
-@itemx TARGET_FF
-@itemx TARGET_CR
-C constant expressions for the integer values for escape sequences
-@samp{\v}, @samp{\f} and @samp{\r}.
-@end table
+@multitable {@code{TARGET_NEWLINE}} {Escape} {ASCII character}
+@item Macro @tab Escape @tab ASCII character
+@item @code{TARGET_BELL} @tab @kbd{\a} @tab @code{07}, @code{BEL}
+@item @code{TARGET_CR} @tab @kbd{\r} @tab @code{0D}, @code{CR}
+@item @code{TARGET_ESC} @tab @kbd{\e}, @kbd{\E} @tab @code{1B}, @code{ESC}
+@item @code{TARGET_FF} @tab @kbd{\f} @tab @code{0C}, @code{FF}
+@item @code{TARGET_NEWLINE} @tab @kbd{\n} @tab @code{0A}, @code{LF}
+@item @code{TARGET_TAB} @tab @kbd{\t} @tab @code{09}, @code{HT}
+@item @code{TARGET_VT} @tab @kbd{\v} @tab @code{0B}, @code{VT}
+@end multitable
+
+@noindent
+Note that the @kbd{\e} and @kbd{\E} escapes are GNU extensions, not
+part of the C standard.
@node Registers
@section Register Usage
@c prevent bad page break with this line
Registers have various characteristics.
-@table @code
-@findex FIRST_PSEUDO_REGISTER
-@item FIRST_PSEUDO_REGISTER
+@defmac FIRST_PSEUDO_REGISTER
Number of hardware registers known to the compiler. They receive
numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first
pseudo register's number really is assigned the number
@code{FIRST_PSEUDO_REGISTER}.
+@end defmac
-@item FIXED_REGISTERS
-@findex FIXED_REGISTERS
+@defmac FIXED_REGISTERS
@cindex fixed register
An initializer that says which registers are used for fixed purposes
all throughout the compiled code and are therefore not available for
by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by
the user with the command options @option{-ffixed-@var{reg}},
@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}.
+@end defmac
-@findex CALL_USED_REGISTERS
-@item CALL_USED_REGISTERS
+@defmac CALL_USED_REGISTERS
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler
automatically saves it on function entry and restores it on function
exit, if the register is used within the function.
+@end defmac
-@findex CALL_REALLY_USED_REGISTERS
-@item CALL_REALLY_USED_REGISTERS
+@defmac CALL_REALLY_USED_REGISTERS
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
This macro is optional. If not specified, it defaults to the value
of @code{CALL_USED_REGISTERS}.
+@end defmac
-@findex HARD_REGNO_CALL_PART_CLOBBERED
-@item HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode})
+@defmac HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode})
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
call without some part of it being clobbered. For most machines this
macro need not be defined. It is only required for machines that do not
preserve the entire contents of a register across a call.
+@end defmac
-@findex CONDITIONAL_REGISTER_USAGE
@findex fixed_regs
@findex call_used_regs
-@item CONDITIONAL_REGISTER_USAGE
+@findex global_regs
+@findex reg_names
+@findex reg_class_contents
+@defmac CONDITIONAL_REGISTER_USAGE
Zero or more C statements that may conditionally modify five variables
@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},
@code{reg_names}, and @code{reg_class_contents}, to take into account
flags, you may indicate this to GCC by using this macro to modify
@code{fixed_regs} and @code{call_used_regs} to 1 for each of the
registers in the classes which should not be used by GCC@. Also define
-the macro @code{REG_CLASS_FROM_LETTER} to return @code{NO_REGS} if it
+the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT}
+to return @code{NO_REGS} if it
is called with a letter for a class that shouldn't be used.
(However, if this class is not included in @code{GENERAL_REGS} and all
of the insn patterns whose constraints permit this class are
controlled by target switches, then GCC will automatically avoid using
these registers when the target switches are opposed to them.)
+@end defmac
-@findex NON_SAVING_SETJMP
-@item NON_SAVING_SETJMP
+@defmac NON_SAVING_SETJMP
If this macro is defined and has a nonzero value, it means that
@code{setjmp} and related functions fail to save the registers, or that
@code{longjmp} fails to restore them. To compensate, the compiler
avoids putting variables in registers in functions that use
@code{setjmp}.
+@end defmac
-@findex INCOMING_REGNO
-@item INCOMING_REGNO (@var{out})
+@defmac INCOMING_REGNO (@var{out})
Define this macro if the target machine has register windows. This C
expression returns the register number as seen by the called function
corresponding to the register number @var{out} as seen by the calling
function. Return @var{out} if register number @var{out} is not an
outbound register.
+@end defmac
-@findex OUTGOING_REGNO
-@item OUTGOING_REGNO (@var{in})
+@defmac OUTGOING_REGNO (@var{in})
Define this macro if the target machine has register windows. This C
expression returns the register number as seen by the calling function
corresponding to the register number @var{in} as seen by the called
function. Return @var{in} if register number @var{in} is not an inbound
register.
+@end defmac
-@findex LOCAL_REGNO
-@item LOCAL_REGNO (@var{regno})
+@defmac LOCAL_REGNO (@var{regno})
Define this macro if the target machine has register windows. This C
expression returns true if the register is call-saved but is in the
register window. Unlike most call-saved registers, such registers
need not be explicitly restored on function exit or during non-local
gotos.
+@end defmac
-@ignore
-@findex PC_REGNUM
-@item PC_REGNUM
+@defmac PC_REGNUM
If the program counter has a register number, define this as that
register number. Otherwise, do not define it.
-@end ignore
-@end table
+@end defmac
@node Allocation Order
@subsection Order of Allocation of Registers
@c prevent bad page break with this line
Registers are allocated in order.
-@table @code
-@findex REG_ALLOC_ORDER
-@item REG_ALLOC_ORDER
+@defmac REG_ALLOC_ORDER
If defined, an initializer for a vector of integers, containing the
numbers of hard registers in the order in which GCC should prefer
to use them (from most preferred to least).
instruction supports only sequences of consecutive registers. On such
machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists
the highest numbered allocable register first.
+@end defmac
-@findex ORDER_REGS_FOR_LOCAL_ALLOC
-@item ORDER_REGS_FOR_LOCAL_ALLOC
+@defmac ORDER_REGS_FOR_LOCAL_ALLOC
A C statement (sans semicolon) to choose the order in which to allocate
hard registers for pseudo-registers local to a basic block.
@code{reg_alloc_order} before execution of the macro.
On most machines, it is not necessary to define this macro.
-@end table
+@end defmac
@node Values in Registers
@subsection How Values Fit in Registers
(specifically, which machine modes) each register can hold, and how many
consecutive registers are needed for a given mode.
-@table @code
-@findex HARD_REGNO_NREGS
-@item HARD_REGNO_NREGS (@var{regno}, @var{mode})
+@defmac HARD_REGNO_NREGS (@var{regno}, @var{mode})
A C expression for the number of consecutive hard registers, starting
at register number @var{regno}, required to hold a value of mode
@var{mode}.
((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) \
/ UNITS_PER_WORD)
@end smallexample
+@end defmac
-@findex HARD_REGNO_MODE_OK
-@item HARD_REGNO_MODE_OK (@var{regno}, @var{mode})
+@defmac HARD_REGNO_MODE_OK (@var{regno}, @var{mode})
A C expression that is nonzero if it is permissible to store a value
of mode @var{mode} in hard register number @var{regno} (or in several
registers starting with that one). For a machine where all registers
register if floating point arithmetic is not being done. As long as the
floating registers are not in class @code{GENERAL_REGS}, they will not
be used unless some pattern's constraint asks for one.
+@end defmac
-@findex MODES_TIEABLE_P
-@item MODES_TIEABLE_P (@var{mode1}, @var{mode2})
+@defmac MODES_TIEABLE_P (@var{mode1}, @var{mode2})
A C expression that is nonzero if a value of mode
@var{mode1} is accessible in mode @var{mode2} without copying.
You should define this macro to return nonzero in as many cases as
possible since doing so will allow GCC to perform better register
allocation.
+@end defmac
-@findex AVOID_CCMODE_COPIES
-@item AVOID_CCMODE_COPIES
+@defmac AVOID_CCMODE_COPIES
Define this macro if the compiler should avoid copies to/from @code{CCmode}
registers. You should only define this macro if support for copying to/from
@code{CCmode} is incomplete.
-@end table
+@end defmac
@node Leaf Functions
@subsection Handling Leaf Functions
registers in order to output a leaf function. The following macros
accomplish this.
-@table @code
-@findex LEAF_REGISTERS
-@item LEAF_REGISTERS
+@defmac LEAF_REGISTERS
Name of a char vector, indexed by hard register number, which
contains 1 for a register that is allowable in a candidate for leaf
function treatment.
Define this macro only if the target machine offers a way to optimize
the treatment of leaf functions.
+@end defmac
-@findex LEAF_REG_REMAP
-@item LEAF_REG_REMAP (@var{regno})
+@defmac LEAF_REG_REMAP (@var{regno})
A C expression whose value is the register number to which @var{regno}
should be renumbered, when a function is treated as a leaf function.
Define this macro only if the target machine offers a way to optimize the
treatment of leaf functions, and registers need to be renumbered to do
this.
-@end table
+@end defmac
@findex current_function_is_leaf
@findex current_function_uses_only_leaf_regs
@subsection Registers That Form a Stack
There are special features to handle computers where some of the
-``registers'' form a stack, as in the 80387 coprocessor for the 80386.
-Stack registers are normally written by pushing onto the stack, and are
-numbered relative to the top of the stack.
+``registers'' form a stack. Stack registers are normally written by
+pushing onto the stack, and are numbered relative to the top of the
+stack.
Currently, GCC can only handle one group of stack-like registers, and
-they must be consecutively numbered.
-
-@table @code
-@findex STACK_REGS
-@item STACK_REGS
+they must be consecutively numbered. Furthermore, the existing
+support for stack-like registers is specific to the 80387 floating
+point coprocessor. If you have a new architecture that uses
+stack-like registers, you will need to do substantial work on
+@file{reg-stack.c} and write your machine description to cooperate
+with it, as well as defining these macros.
+
+@defmac STACK_REGS
Define this if the machine has any stack-like registers.
+@end defmac
-@findex FIRST_STACK_REG
-@item FIRST_STACK_REG
+@defmac FIRST_STACK_REG
The number of the first stack-like register. This one is the top
of the stack.
+@end defmac
-@findex LAST_STACK_REG
-@item LAST_STACK_REG
+@defmac LAST_STACK_REG
The number of the last stack-like register. This one is the bottom of
the stack.
-@end table
+@end defmac
@node Register Classes
@section Register Classes
single-byte values can be loaded or stored. This is so that
@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return.
-@table @code
-@findex enum reg_class
-@item enum reg_class
+@deftp {Data type} {enum reg_class}
An enumeral type that must be defined with all the register class names
as enumeral values. @code{NO_REGS} must be first. @code{ALL_REGS}
must be the last register class, followed by one more enumeral value,
Each register class has a number, which is the value of casting
the class name to type @code{int}. The number serves as an index
in many of the tables described below.
+@end deftp
-@findex N_REG_CLASSES
-@item N_REG_CLASSES
+@defmac N_REG_CLASSES
The number of distinct register classes, defined as follows:
@example
#define N_REG_CLASSES (int) LIM_REG_CLASSES
@end example
+@end defmac
-@findex REG_CLASS_NAMES
-@item REG_CLASS_NAMES
+@defmac REG_CLASS_NAMES
An initializer containing the names of the register classes as C string
constants. These names are used in writing some of the debugging dumps.
+@end defmac
-@findex REG_CLASS_CONTENTS
-@item REG_CLASS_CONTENTS
+@defmac REG_CLASS_CONTENTS
An initializer containing the contents of the register classes, as integers
which are bit masks. The @var{n}th integer specifies the contents of class
@var{n}. The way the integer @var{mask} is interpreted is that
In this situation, the first integer in each sub-initializer corresponds to
registers 0 through 31, the second integer to registers 32 through 63, and
so on.
+@end defmac
-@findex REGNO_REG_CLASS
-@item REGNO_REG_CLASS (@var{regno})
+@defmac REGNO_REG_CLASS (@var{regno})
A C expression whose value is a register class containing hard register
@var{regno}. In general there is more than one such class; choose a class
which is @dfn{minimal}, meaning that no smaller class also contains the
register.
+@end defmac
-@findex BASE_REG_CLASS
-@item BASE_REG_CLASS
+@defmac BASE_REG_CLASS
A macro whose definition is the name of the class to which a valid
base register must belong. A base register is one used in an address
which is the register value plus a displacement.
+@end defmac
-@findex MODE_BASE_REG_CLASS
-@item MODE_BASE_REG_CLASS (@var{mode})
+@defmac MODE_BASE_REG_CLASS (@var{mode})
This is a variation of the @code{BASE_REG_CLASS} macro which allows
-the selection of a base register in a mode depenedent manner. If
+the selection of a base register in a mode dependent manner. If
@var{mode} is VOIDmode then it should return the same value as
@code{BASE_REG_CLASS}.
+@end defmac
-@findex INDEX_REG_CLASS
-@item INDEX_REG_CLASS
+@defmac INDEX_REG_CLASS
A macro whose definition is the name of the class to which a valid
index register must belong. An index register is one used in an
address where its value is either multiplied by a scale factor or
added to another register (as well as added to a displacement).
+@end defmac
-@findex REG_CLASS_FROM_LETTER
-@item REG_CLASS_FROM_LETTER (@var{char})
+@defmac CONSTRAINT_LEN (@var{char}, @var{str})
+For the constraint at the start of @var{str}, which starts with the letter
+@var{c}, return the length. This allows you to have register class /
+constant / extra constraints that are longer than a single letter;
+you don't need to define this macro if you can do with single-letter
+constraints only. The definition of this macro should use
+DEFAULT_CONSTRAINT_LEN for all the characters that you don't want
+to handle specially.
+There are some sanity checks in genoutput.c that check the constraint lengths
+for the md file, so you can also use this macro to help you while you are
+transitioning from a byzantine single-letter-constraint scheme: when you
+return a negative length for a constraint you want to re-use, genoutput
+will complain about every instance where it is used in the md file.
+@end defmac
+
+@defmac REG_CLASS_FROM_LETTER (@var{char})
A C expression which defines the machine-dependent operand constraint
letters for register classes. If @var{char} is such a letter, the
value should be the register class corresponding to it. Otherwise,
the value should be @code{NO_REGS}. The register letter @samp{r},
corresponding to class @code{GENERAL_REGS}, will not be passed
to this macro; you do not need to handle it.
+@end defmac
-@findex REGNO_OK_FOR_BASE_P
-@item REGNO_OK_FOR_BASE_P (@var{num})
+@defmac REG_CLASS_FROM_CONSTRAINT (@var{char}, @var{str})
+Like @code{REG_CLASS_FROM_LETTER}, but you also get the constraint string
+passed in @var{str}, so that you can use suffixes to distinguish between
+different variants.
+@end defmac
+
+@defmac REGNO_OK_FOR_BASE_P (@var{num})
A C expression which is nonzero if register number @var{num} is
suitable for use as a base register in operand addresses. It may be
either a suitable hard register or a pseudo register that has been
allocated such a hard register.
+@end defmac
-@findex REGNO_MODE_OK_FOR_BASE_P
-@item REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
+@defmac REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that
that expression may examine the mode of the memory reference in
@var{mode}. You should define this macro if the mode of the memory
reference affects whether a register may be used as a base register. If
you define this macro, the compiler will use it instead of
@code{REGNO_OK_FOR_BASE_P}.
+@end defmac
-@findex REGNO_OK_FOR_INDEX_P
-@item REGNO_OK_FOR_INDEX_P (@var{num})
+@defmac REGNO_OK_FOR_INDEX_P (@var{num})
A C expression which is nonzero if register number @var{num} is
suitable for use as an index register in operand addresses. It may be
either a suitable hard register or a pseudo register that has been
may serve in each capacity. The compiler will try both labelings,
looking for one that is valid, and will reload one or both registers
only if neither labeling works.
+@end defmac
-@findex PREFERRED_RELOAD_CLASS
-@item PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
+@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
A C expression that places additional restrictions on the register class
to use when it is necessary to copy value @var{x} into a register in class
@var{class}. The value is a register class; perhaps @var{class}, or perhaps
you can force @var{x} into a memory constant. This is useful on
certain machines where immediate floating values cannot be loaded into
certain kinds of registers.
+@end defmac
-@findex PREFERRED_OUTPUT_RELOAD_CLASS
-@item PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
+@defmac PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
Like @code{PREFERRED_RELOAD_CLASS}, but for output reloads instead of
input reloads. If you don't define this macro, the default is to use
@var{class}, unchanged.
+@end defmac
-@findex LIMIT_RELOAD_CLASS
-@item LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
+@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
A C expression that places additional restrictions on the register class
to use when it is necessary to be able to hold a value of mode
@var{mode} in a reload register for which class @var{class} would
Don't define this macro unless the target machine has limitations which
require the macro to do something nontrivial.
+@end defmac
-@findex SECONDARY_RELOAD_CLASS
-@findex SECONDARY_INPUT_RELOAD_CLASS
-@findex SECONDARY_OUTPUT_RELOAD_CLASS
-@item SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@itemx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@itemx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
Many machines have some registers that cannot be copied directly to or
from memory or even from other types of registers. An example is the
@samp{MQ} register, which on most machines, can only be copied to or
the copy and the @code{mov@var{m}} pattern should use memory as an
intermediate storage. This case often occurs between floating-point and
general registers.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED
-@item SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m})
+@defmac SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m})
Certain machines have the property that some registers cannot be copied
to some other registers without using memory. Define this macro on
those machines to be a C expression that is nonzero if objects of mode
and loading that memory location into a register of @var{class2}.
Do not define this macro if its value would always be zero.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED_RTX
-@item SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
+@defmac SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
Normally when @code{SECONDARY_MEMORY_NEEDED} is defined, the compiler
allocates a stack slot for a memory location needed for register copies.
If this macro is defined, the compiler instead uses the memory location
Do not define this macro if you do not define
@code{SECONDARY_MEMORY_NEEDED}.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED_MODE
-@item SECONDARY_MEMORY_NEEDED_MODE (@var{mode})
+@defmac SECONDARY_MEMORY_NEEDED_MODE (@var{mode})
When the compiler needs a secondary memory location to copy between two
registers of mode @var{mode}, it normally allocates sufficient memory to
hold a quantity of @code{BITS_PER_WORD} bits and performs the store and
Do not define this macro if you do not define
@code{SECONDARY_MEMORY_NEEDED} or if widening @var{mode} to a mode that
is @code{BITS_PER_WORD} bits wide is correct for your machine.
+@end defmac
-@findex SMALL_REGISTER_CLASSES
-@item SMALL_REGISTER_CLASSES
+@defmac SMALL_REGISTER_CLASSES
On some machines, it is risky to let hard registers live across arbitrary
insns. Typically, these machines have instructions that require values
to be in specific registers (like an accumulator), and reload will fail
with a nonzero value when it is required, the compiler will run out of
spill registers and print a fatal error message. For most machines, you
should not define this macro at all.
+@end defmac
-@findex CLASS_LIKELY_SPILLED_P
-@item CLASS_LIKELY_SPILLED_P (@var{class})
+@defmac CLASS_LIKELY_SPILLED_P (@var{class})
A C expression whose value is nonzero if pseudos that have been assigned
to registers of class @var{class} would likely be spilled because
registers of @var{class} are needed for spill registers.
reallocation, you should not change the definition of this macro since
the only effect of such a definition would be to slow down register
allocation.
+@end defmac
-@findex CLASS_MAX_NREGS
-@item CLASS_MAX_NREGS (@var{class}, @var{mode})
+@defmac CLASS_MAX_NREGS (@var{class}, @var{mode})
A C expression for the maximum number of consecutive registers
of class @var{class} needed to hold a value of mode @var{mode}.
This macro helps control the handling of multiple-word values
in the reload pass.
+@end defmac
-@item CLASS_CANNOT_CHANGE_MODE
-If defined, a C expression for a class that contains registers for
-which the compiler may not change modes arbitrarily.
-
-@item CLASS_CANNOT_CHANGE_MODE_P(@var{from}, @var{to})
-A C expression that is true if, for a register in
-@code{CLASS_CANNOT_CHANGE_MODE}, the requested mode punning is invalid.
+@defmac CANNOT_CHANGE_MODE_CLASS (@var{from}, @var{to}, @var{class})
+If defined, a C expression that returns nonzero for a @var{class} for which
+a change from mode @var{from} to mode @var{to} is invalid.
For the example, loading 32-bit integer or floating-point objects into
floating-point registers on the Alpha extends them to 64 bits.
Therefore loading a 64-bit object and then storing it as a 32-bit object
does not store the low-order 32 bits, as would be the case for a normal
-register. Therefore, @file{alpha.h} defines @code{CLASS_CANNOT_CHANGE_MODE}
-as @code{FLOAT_REGS} and @code{CLASS_CANNOT_CHANGE_MODE_P} restricts
-mode changes to same-size modes.
+register. Therefore, @file{alpha.h} defines @code{CANNOT_CHANGE_MODE_CLASS}
+as below:
-Compare this to IA-64, which extends floating-point values to 82-bits,
-and stores 64-bit integers in a different format than 64-bit doubles.
-Therefore @code{CLASS_CANNOT_CHANGE_MODE_P} is always true.
-@end table
+@example
+#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \
+ (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \
+ ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0)
+@end example
+@end defmac
Three other special macros describe which operands fit which constraint
letters.
-@table @code
-@findex CONST_OK_FOR_LETTER_P
-@item CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
+@defmac CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
A C expression that defines the machine-dependent operand constraint
letters (@samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}) that specify
particular ranges of integer values. If @var{c} is one of those
the appropriate range and return 1 if so, 0 otherwise. If @var{c} is
not one of those letters, the value should be 0 regardless of
@var{value}.
+@end defmac
-@findex CONST_DOUBLE_OK_FOR_LETTER_P
-@item CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
+@defmac CONST_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
+Like @code{CONST_OK_FOR_LETTER_P}, but you also get the constraint
+string passed in @var{str}, so that you can use suffixes to distinguish
+between different variants.
+@end defmac
+
+@defmac CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
A C expression that defines the machine-dependent operand constraint
letters that specify particular ranges of @code{const_double} values
(@samp{G} or @samp{H}).
@code{DImode} fixed-point constants. A given letter can accept either
or both kinds of values. It can use @code{GET_MODE} to distinguish
between these kinds.
+@end defmac
+
+@defmac CONST_DOUBLE_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
+Like @code{CONST_DOUBLE_OK_FOR_LETTER_P}, but you also get the constraint
+string passed in @var{str}, so that you can use suffixes to distinguish
+between different variants.
+@end defmac
-@findex EXTRA_CONSTRAINT
-@item EXTRA_CONSTRAINT (@var{value}, @var{c})
+@defmac EXTRA_CONSTRAINT (@var{value}, @var{c})
A C expression that defines the optional machine-dependent constraint
letters that can be used to segregate specific types of operands, usually
memory references, for the target machine. Any letter that is not
-elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER}
+elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER} /
+@code{REG_CLASS_FROM_CONSTRAINT}
may be used. Normally this macro will not be defined.
If it is required for a particular target machine, it should return 1
a @samp{Q} constraint on the input and @samp{r} on the output. The next
alternative specifies @samp{m} on the input and a register class that
does not include r0 on the output.
+@end defmac
-@findex EXTRA_MEMORY_CONSTRAINT
-@item EXTRA_MEMORY_CONSTRAINT (@var{c})
+@defmac EXTRA_CONSTRAINT_STR (@var{value}, @var{c}, @var{str})
+Like @code{EXTRA_CONSTRAINT}, but you also get the constraint string passed
+in @var{str}, so that you can use suffixes to distinguish between different
+variants.
+@end defmac
+
+@defmac EXTRA_MEMORY_CONSTRAINT (@var{c}, @var{str})
A C expression that defines the optional machine-dependent constraint
letters, amongst those accepted by @code{EXTRA_CONSTRAINT}, that should
be treated like memory constraints by the reload pass.
It should return 1 if the operand type represented by the constraint
-letter @var{c} comprises a subset of all memory references including
+at the start of @var{str}, the first letter of which is the letter @var{c},
+ comprises a subset of all memory references including
all those whose address is simply a base register. This allows the reload
pass to reload an operand, if it does not directly correspond to the operand
type of @var{c}, by copying its address into a base register.
reload pass knows it can be reloaded by copying the memory address
into a base register if required. This is analogous to the way
a @samp{o} constraint can handle any memory operand.
+@end defmac
-@findex EXTRA_ADDRESS_CONSTRAINT
-@item EXTRA_ADDRESS_CONSTRAINT (@var{c})
+@defmac EXTRA_ADDRESS_CONSTRAINT (@var{c}, @var{str})
A C expression that defines the optional machine-dependent constraint
-letters, amongst those accepted by @code{EXTRA_CONSTRAINT}, that should
+letters, amongst those accepted by @code{EXTRA_CONSTRAINT} /
+@code{EXTRA_CONSTRAINT_STR}, that should
be treated like address constraints by the reload pass.
It should return 1 if the operand type represented by the constraint
-letter @var{c} comprises a subset of all memory addresses including
+at the start of @var{str}, which starts with the letter @var{c}, comprises
+a subset of all memory addresses including
all those that consist of just a base register. This allows the reload
pass to reload an operand, if it does not directly correspond to the operand
-type of @var{c}, by copying it into a base register.
+type of @var{str}, by copying it into a base register.
Any constraint marked as @code{EXTRA_ADDRESS_CONSTRAINT} can only
be used with the @code{address_operand} predicate. It is treated
analogously to the @samp{p} constraint.
-@end table
+@end defmac
@node Stack and Calling
@section Stack Layout and Calling Conventions
@c prevent bad page break with this line
Here is the basic stack layout.
-@table @code
-@findex STACK_GROWS_DOWNWARD
-@item STACK_GROWS_DOWNWARD
+@defmac STACK_GROWS_DOWNWARD
Define this macro if pushing a word onto the stack moves the stack
pointer to a smaller address.
When we say, ``define this macro if @dots{},'' it means that the
compiler checks this macro only with @code{#ifdef} so the precise
definition used does not matter.
+@end defmac
-@findex STACK_PUSH_CODE
-@item STACK_PUSH_CODE
-
+@defmac STACK_PUSH_CODE
This macro defines the operation used when something is pushed
on the stack. In RTL, a push operation will be
@code{(set (mem (STACK_PUSH_CODE (reg sp))) @dots{})}
The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
defined, which is almost always right, and @code{PRE_INC} otherwise,
which is often wrong.
+@end defmac
-@findex FRAME_GROWS_DOWNWARD
-@item FRAME_GROWS_DOWNWARD
+@defmac FRAME_GROWS_DOWNWARD
Define this macro if the addresses of local variable slots are at negative
offsets from the frame pointer.
+@end defmac
-@findex ARGS_GROW_DOWNWARD
-@item ARGS_GROW_DOWNWARD
+@defmac ARGS_GROW_DOWNWARD
Define this macro if successive arguments to a function occupy decreasing
addresses on the stack.
+@end defmac
-@findex STARTING_FRAME_OFFSET
-@item STARTING_FRAME_OFFSET
+@defmac STARTING_FRAME_OFFSET
Offset from the frame pointer to the first local variable slot to be allocated.
If @code{FRAME_GROWS_DOWNWARD}, find the next slot's offset by
value @code{STARTING_FRAME_OFFSET}.
@c i'm not sure if the above is still correct.. had to change it to get
@c rid of an overfull. --mew 2feb93
+@end defmac
+
+@defmac STACK_ALIGNMENT_NEEDED
+Define to zero to disable final alignment of the stack during reload.
+The nonzero default for this macro is suitable for most ports.
-@findex STACK_POINTER_OFFSET
-@item STACK_POINTER_OFFSET
+On ports where @code{STARTING_FRAME_OFFSET} is nonzero or where there
+is a register save block following the local block that doesn't require
+alignment to @code{STACK_BOUNDARY}, it may be beneficial to disable
+stack alignment and do it in the backend.
+@end defmac
+
+@defmac STACK_POINTER_OFFSET
Offset from the stack pointer register to the first location at which
outgoing arguments are placed. If not specified, the default value of
zero is used. This is the proper value for most machines.
If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
the first location at which outgoing arguments are placed.
+@end defmac
-@findex FIRST_PARM_OFFSET
-@item FIRST_PARM_OFFSET (@var{fundecl})
+@defmac FIRST_PARM_OFFSET (@var{fundecl})
Offset from the argument pointer register to the first argument's
address. On some machines it may depend on the data type of the
function.
If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
the first argument's address.
+@end defmac
-@findex STACK_DYNAMIC_OFFSET
-@item STACK_DYNAMIC_OFFSET (@var{fundecl})
+@defmac STACK_DYNAMIC_OFFSET (@var{fundecl})
Offset from the stack pointer register to an item dynamically allocated
on the stack, e.g., by @code{alloca}.
The default value for this macro is @code{STACK_POINTER_OFFSET} plus the
length of the outgoing arguments. The default is correct for most
machines. See @file{function.c} for details.
+@end defmac
-@findex DYNAMIC_CHAIN_ADDRESS
-@item DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
+@defmac DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
A C expression whose value is RTL representing the address in a stack
frame where the pointer to the caller's frame is stored. Assume that
@var{frameaddr} is an RTL expression for the address of the stack frame
If you don't define this macro, the default is to return the value
of @var{frameaddr}---that is, the stack frame address is also the
address of the stack word that points to the previous frame.
+@end defmac
-@findex SETUP_FRAME_ADDRESSES
-@item SETUP_FRAME_ADDRESSES
+@defmac SETUP_FRAME_ADDRESSES
If defined, a C expression that produces the machine-specific code to
setup the stack so that arbitrary frames can be accessed. For example,
on the SPARC, we must flush all of the register windows to the stack
before we can access arbitrary stack frames. You will seldom need to
define this macro.
+@end defmac
-@findex BUILTIN_SETJMP_FRAME_VALUE
-@item BUILTIN_SETJMP_FRAME_VALUE
+@defmac BUILTIN_SETJMP_FRAME_VALUE
If defined, a C expression that contains an rtx that is used to store
the address of the current frame into the built in @code{setjmp} buffer.
The default value, @code{virtual_stack_vars_rtx}, is correct for most
machines. One reason you may need to define this macro is if
@code{hard_frame_pointer_rtx} is the appropriate value on your machine.
+@end defmac
-@findex RETURN_ADDR_RTX
-@item RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
+@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
A C expression whose value is RTL representing the value of the return
address for the frame @var{count} steps up from the current frame, after
the prologue. @var{frameaddr} is the frame pointer of the @var{count}
The value of the expression must always be the correct address when
@var{count} is zero, but may be @code{NULL_RTX} if there is not way to
determine the return address of other frames.
+@end defmac
-@findex RETURN_ADDR_IN_PREVIOUS_FRAME
-@item RETURN_ADDR_IN_PREVIOUS_FRAME
+@defmac RETURN_ADDR_IN_PREVIOUS_FRAME
Define this if the return address of a particular stack frame is accessed
from the frame pointer of the previous stack frame.
+@end defmac
-@findex INCOMING_RETURN_ADDR_RTX
-@item INCOMING_RETURN_ADDR_RTX
+@defmac INCOMING_RETURN_ADDR_RTX
A C expression whose value is RTL representing the location of the
incoming return address at the beginning of any function, before the
prologue. This RTL is either a @code{REG}, indicating that the return
If this RTL is a @code{REG}, you should also define
@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}.
+@end defmac
-@findex INCOMING_FRAME_SP_OFFSET
-@item INCOMING_FRAME_SP_OFFSET
+@defmac INCOMING_FRAME_SP_OFFSET
A C expression whose value is an integer giving the offset, in bytes,
from the value of the stack pointer register to the top of the stack
frame at the beginning of any function, before the prologue. The top of
You only need to define this macro if you want to support call frame
debugging information like that provided by DWARF 2.
+@end defmac
-@findex ARG_POINTER_CFA_OFFSET
-@item ARG_POINTER_CFA_OFFSET (@var{fundecl})
+@defmac ARG_POINTER_CFA_OFFSET (@var{fundecl})
A C expression whose value is an integer giving the offset, in bytes,
from the argument pointer to the canonical frame address (cfa). The
final value should coincide with that calculated by
You only need to define this macro if the default is incorrect, and you
want to support call frame debugging information like that provided by
DWARF 2.
+@end defmac
-@findex SMALL_STACK
-@item SMALL_STACK
+@defmac SMALL_STACK
Define this macro if the stack size for the target is very small. This
has the effect of disabling gcc's built-in @samp{alloca}, though
@samp{__builtin_alloca} is not affected.
-@end table
+@end defmac
@node Exception Handling
@subsection Exception Handling Support
@cindex exception handling
-@table @code
-@findex EH_RETURN_DATA_REGNO
-@item EH_RETURN_DATA_REGNO (@var{N})
+@defmac EH_RETURN_DATA_REGNO (@var{N})
A C expression whose value is the @var{N}th register number used for
data by exception handlers, or @code{INVALID_REGNUM} if fewer than
@var{N} registers are usable.
You must define this macro if you want to support call frame exception
handling like that provided by DWARF 2.
+@end defmac
-@findex EH_RETURN_STACKADJ_RTX
-@item EH_RETURN_STACKADJ_RTX
+@defmac EH_RETURN_STACKADJ_RTX
A C expression whose value is RTL representing a location in which
to store a stack adjustment to be applied before function return.
This is used to unwind the stack to an exception handler's call frame.
Typically this is a call-clobbered hard register that is otherwise
untouched by the epilogue, but could also be a stack slot.
-You must define this macro if you want to support call frame exception
-handling like that provided by DWARF 2.
+Do not define this macro if the stack pointer is saved and restored
+by the regular prolog and epilog code in the call frame itself; in
+this case, the exception handling library routines will update the
+stack location to be restored in place. Otherwise, you must define
+this macro if you want to support call frame exception handling like
+that provided by DWARF 2.
+@end defmac
-@findex EH_RETURN_HANDLER_RTX
-@item EH_RETURN_HANDLER_RTX
+@defmac EH_RETURN_HANDLER_RTX
A C expression whose value is RTL representing a location in which
to store the address of an exception handler to which we should
return. It will not be assigned on code paths that return normally.
return address is stored. For targets that return by popping an
address off the stack, this might be a memory address just below
the @emph{target} call frame rather than inside the current call
-frame. @code{EH_RETURN_STACKADJ_RTX} will have already been assigned,
-so it may be used to calculate the location of the target call frame.
+frame. If defined, @code{EH_RETURN_STACKADJ_RTX} will have already
+been assigned, so it may be used to calculate the location of the
+target call frame.
Some targets have more complex requirements than storing to an
address calculable during initial code generation. In that case
If you want to support call frame exception handling, you must
define either this macro or the @code{eh_return} instruction pattern.
+@end defmac
+
+@defmac RETURN_ADDR_OFFSET
+If defined, an integer-valued C expression for which rtl will be generated
+to add it to the exception handler address before it is searched in the
+exception handling tables, and to subtract it again from the address before
+using it to return to the exception handler.
+@end defmac
-@findex ASM_PREFERRED_EH_DATA_FORMAT
-@item ASM_PREFERRED_EH_DATA_FORMAT(@var{code}, @var{global})
+@defmac ASM_PREFERRED_EH_DATA_FORMAT (@var{code}, @var{global})
This macro chooses the encoding of pointers embedded in the exception
handling sections. If at all possible, this should be defined such
that the exception handling section will not require dynamic relocations,
If this macro is not defined, pointers will not be encoded but
represented directly.
+@end defmac
-@findex ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
-@item ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
+@defmac ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
This macro allows the target to emit whatever special magic is required
to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}.
Generic code takes care of pc-relative and indirect encodings; this must
handled. @var{encoding} is the format chosen, @var{size} is the number
of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF}
to be emitted.
+@end defmac
-@findex MD_FALLBACK_FRAME_STATE_FOR
-@item MD_FALLBACK_FRAME_STATE_FOR(@var{context}, @var{fs}, @var{success})
+@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs}, @var{success})
This macro allows the target to add cpu and operating system specific
code to the call-frame unwinder for use when there is no unwind data
available. The most common reason to implement this macro is to unwind
addresses should be updated in @var{fs} and the macro should branch to
@var{success}. If the frame cannot be decoded, the macro should do
nothing.
-@end table
+
+For proper signal handling in Java this macro is accompanied by
+@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers.
+@end defmac
@node Stack Checking
@subsection Specifying How Stack Checking is Done
Normally, you will use the default values of these macros, so GCC
will use the third approach.
-@table @code
-@findex STACK_CHECK_BUILTIN
-@item STACK_CHECK_BUILTIN
+@defmac STACK_CHECK_BUILTIN
A nonzero value if stack checking is done by the configuration files in a
machine-dependent manner. You should define this macro if stack checking
is require by the ABI of your machine or if you would like to have to stack
checking in some more efficient way than GCC's portable approach.
The default value of this macro is zero.
+@end defmac
-@findex STACK_CHECK_PROBE_INTERVAL
-@item STACK_CHECK_PROBE_INTERVAL
+@defmac STACK_CHECK_PROBE_INTERVAL
An integer representing the interval at which GCC must generate stack
probe instructions. You will normally define this macro to be no larger
than the size of the ``guard pages'' at the end of a stack area. The
default value of 4096 is suitable for most systems.
+@end defmac
-@findex STACK_CHECK_PROBE_LOAD
-@item STACK_CHECK_PROBE_LOAD
+@defmac STACK_CHECK_PROBE_LOAD
A integer which is nonzero if GCC should perform the stack probe
as a load instruction and zero if GCC should use a store instruction.
The default is zero, which is the most efficient choice on most systems.
+@end defmac
-@findex STACK_CHECK_PROTECT
-@item STACK_CHECK_PROTECT
+@defmac STACK_CHECK_PROTECT
The number of bytes of stack needed to recover from a stack overflow,
for languages where such a recovery is supported. The default value of
75 words should be adequate for most machines.
+@end defmac
-@findex STACK_CHECK_MAX_FRAME_SIZE
-@item STACK_CHECK_MAX_FRAME_SIZE
+@defmac STACK_CHECK_MAX_FRAME_SIZE
The maximum size of a stack frame, in bytes. GCC will generate probe
instructions in non-leaf functions to ensure at least this many bytes of
stack are available. If a stack frame is larger than this size, stack
checking will not be reliable and GCC will issue a warning. The
default is chosen so that GCC only generates one instruction on most
systems. You should normally not change the default value of this macro.
+@end defmac
-@findex STACK_CHECK_FIXED_FRAME_SIZE
-@item STACK_CHECK_FIXED_FRAME_SIZE
+@defmac STACK_CHECK_FIXED_FRAME_SIZE
GCC uses this value to generate the above warning message. It
represents the amount of fixed frame used by a function, not including
space for any callee-saved registers, temporaries and user variables.
You need only specify an upper bound for this amount and will normally
use the default of four words.
+@end defmac
-@findex STACK_CHECK_MAX_VAR_SIZE
-@item STACK_CHECK_MAX_VAR_SIZE
+@defmac STACK_CHECK_MAX_VAR_SIZE
The maximum size, in bytes, of an object that GCC will place in the
fixed area of the stack frame when the user specifies
@option{-fstack-check}.
GCC computed the default from the values of the above macros and you will
normally not need to override that default.
-@end table
+@end defmac
@need 2000
@node Frame Registers
@c prevent bad page break with this line
This discusses registers that address the stack frame.
-@table @code
-@findex STACK_POINTER_REGNUM
-@item STACK_POINTER_REGNUM
+@defmac STACK_POINTER_REGNUM
The register number of the stack pointer register, which must also be a
fixed register according to @code{FIXED_REGISTERS}. On most machines,
the hardware determines which register this is.
+@end defmac
-@findex FRAME_POINTER_REGNUM
-@item FRAME_POINTER_REGNUM
+@defmac FRAME_POINTER_REGNUM
The register number of the frame pointer register, which is used to
access automatic variables in the stack frame. On some machines, the
hardware determines which register this is. On other machines, you can
choose any register you wish for this purpose.
+@end defmac
-@findex HARD_FRAME_POINTER_REGNUM
-@item HARD_FRAME_POINTER_REGNUM
+@defmac HARD_FRAME_POINTER_REGNUM
On some machines the offset between the frame pointer and starting
offset of the automatic variables is not known until after register
allocation has been done (for example, because the saved registers are
Do not define this macro if it would be the same as
@code{FRAME_POINTER_REGNUM}.
+@end defmac
-@findex ARG_POINTER_REGNUM
-@item ARG_POINTER_REGNUM
+@defmac ARG_POINTER_REGNUM
The register number of the arg pointer register, which is used to access
the function's argument list. On some machines, this is the same as the
frame pointer register. On some machines, the hardware determines which
pointer register, then you must mark it as a fixed register according to
@code{FIXED_REGISTERS}, or arrange to be able to eliminate it
(@pxref{Elimination}).
+@end defmac
-@findex RETURN_ADDRESS_POINTER_REGNUM
-@item RETURN_ADDRESS_POINTER_REGNUM
+@defmac RETURN_ADDRESS_POINTER_REGNUM
The register number of the return address pointer register, which is used to
access the current function's return address from the stack. On some
machines, the return address is not at a fixed offset from the frame
Do not define this macro unless there is no other way to get the return
address from the stack.
+@end defmac
-@findex STATIC_CHAIN_REGNUM
-@findex STATIC_CHAIN_INCOMING_REGNUM
-@item STATIC_CHAIN_REGNUM
-@itemx STATIC_CHAIN_INCOMING_REGNUM
+@defmac STATIC_CHAIN_REGNUM
+@defmacx STATIC_CHAIN_INCOMING_REGNUM
Register numbers used for passing a function's static chain pointer. If
register windows are used, the register number as seen by the called
function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register
If the static chain is passed in memory, these macros should not be
defined; instead, the next two macros should be defined.
+@end defmac
-@findex STATIC_CHAIN
-@findex STATIC_CHAIN_INCOMING
-@item STATIC_CHAIN
-@itemx STATIC_CHAIN_INCOMING
+@defmac STATIC_CHAIN
+@defmacx STATIC_CHAIN_INCOMING
If the static chain is passed in memory, these macros provide rtx giving
@code{mem} expressions that denote where they are stored.
@code{STATIC_CHAIN} and @code{STATIC_CHAIN_INCOMING} give the locations
If the static chain is passed in a register, the two previous macros should
be defined instead.
+@end defmac
-@findex DWARF_FRAME_REGISTERS
-@item DWARF_FRAME_REGISTERS
+@defmac DWARF_FRAME_REGISTERS
This macro specifies the maximum number of hard registers that can be
saved in a call frame. This is used to size data structures used in
DWARF2 exception handling.
If this macro is not defined, it defaults to
@code{FIRST_PSEUDO_REGISTER}.
+@end defmac
-@findex PRE_GCC3_DWARF_FRAME_REGISTERS
-@item PRE_GCC3_DWARF_FRAME_REGISTERS
+@defmac PRE_GCC3_DWARF_FRAME_REGISTERS
This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided
for backward compatibility in pre GCC 3.0 compiled code.
If this macro is not defined, it defaults to
@code{DWARF_FRAME_REGISTERS}.
+@end defmac
+
+@defmac DWARF_REG_TO_UNWIND_COLUMN (@var{regno})
-@end table
+Define this macro if the target's representation for dwarf registers
+is different than the internal representation for unwind column.
+Given a dwarf register, this macro should return the internal unwind
+column number to use instead.
+
+See the PowerPC's SPE target for an example.
+@end defmac
@node Elimination
@subsection Eliminating Frame Pointer and Arg Pointer
@c prevent bad page break with this line
This is about eliminating the frame pointer and arg pointer.
-@table @code
-@findex FRAME_POINTER_REQUIRED
-@item FRAME_POINTER_REQUIRED
+@defmac FRAME_POINTER_REQUIRED
A C expression which is nonzero if a function must have and use a frame
pointer. This expression is evaluated in the reload pass. If its value is
nonzero the function will have a frame pointer.
In a function that does not require a frame pointer, the frame pointer
register can be allocated for ordinary usage, unless you mark it as a
fixed register. See @code{FIXED_REGISTERS} for more information.
+@end defmac
-@findex INITIAL_FRAME_POINTER_OFFSET
@findex get_frame_size
-@item INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
+@defmac INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
A C statement to store in the variable @var{depth-var} the difference
between the frame pointer and the stack pointer values immediately after
the function prologue. The value would be computed from information
need not be defined. Otherwise, it must be defined even if
@code{FRAME_POINTER_REQUIRED} is defined to always be true; in that
case, you may set @var{depth-var} to anything.
+@end defmac
-@findex ELIMINABLE_REGS
-@item ELIMINABLE_REGS
+@defmac ELIMINABLE_REGS
If defined, this macro specifies a table of register pairs used to
eliminate unneeded registers that point into the stack frame. If it is not
defined, the only elimination attempted by the compiler is to replace
Note that the elimination of the argument pointer with the stack pointer is
specified first since that is the preferred elimination.
+@end defmac
-@findex CAN_ELIMINATE
-@item CAN_ELIMINATE (@var{from-reg}, @var{to-reg})
+@defmac CAN_ELIMINATE (@var{from-reg}, @var{to-reg})
A C expression that returns nonzero if the compiler is allowed to try
to replace register number @var{from-reg} with register number
@var{to-reg}. This macro need only be defined if @code{ELIMINABLE_REGS}
is defined, and will usually be the constant 1, since most of the cases
preventing register elimination are things that the compiler already
knows about.
+@end defmac
-@findex INITIAL_ELIMINATION_OFFSET
-@item INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
+@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
This macro is similar to @code{INITIAL_FRAME_POINTER_OFFSET}. It
specifies the initial difference between the specified pair of
registers. This macro must be defined if @code{ELIMINABLE_REGS} is
defined.
-@end table
+@end defmac
@node Stack Arguments
@subsection Passing Function Arguments on the Stack
on the stack. See the following section for other macros that
control passing certain arguments in registers.
-@table @code
-@findex PROMOTE_PROTOTYPES
-@item PROMOTE_PROTOTYPES
+@defmac PROMOTE_PROTOTYPES
A C expression whose value is nonzero if an argument declared in
a prototype as an integral type smaller than @code{int} should
actually be passed as an @code{int}. In addition to avoiding
errors in certain cases of mismatch, it also makes for better
code on certain machines. If the macro is not defined in target
header files, it defaults to 0.
+@end defmac
-@findex PUSH_ARGS
-@item PUSH_ARGS
+@defmac PUSH_ARGS
A C expression. If nonzero, push insns will be used to pass
outgoing arguments.
If the target machine does not have a push instruction, set it to zero.
That directs GCC to use an alternate strategy: to
allocate the entire argument block and then store the arguments into
it. When @code{PUSH_ARGS} is nonzero, @code{PUSH_ROUNDING} must be defined too.
-On some machines, the definition
+@end defmac
-@findex PUSH_ROUNDING
-@item PUSH_ROUNDING (@var{npushed})
+@defmac PUSH_ARGS_REVERSED
+A C expression. If nonzero, function arguments will be evaluated from
+last to first, rather than from first to last. If this macro is not
+defined, it defaults to @code{PUSH_ARGS} on targets where the stack
+and args grow in opposite directions, and 0 otherwise.
+@end defmac
+
+@defmac PUSH_ROUNDING (@var{npushed})
A C expression that is the number of bytes actually pushed onto the
stack when an instruction attempts to push @var{npushed} bytes.
@example
#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1)
@end example
+@end defmac
-@findex ACCUMULATE_OUTGOING_ARGS
@findex current_function_outgoing_args_size
-@item ACCUMULATE_OUTGOING_ARGS
+@defmac ACCUMULATE_OUTGOING_ARGS
A C expression. If nonzero, the maximum amount of space required for outgoing arguments
will be computed and placed into the variable
@code{current_function_outgoing_args_size}. No space will be pushed
Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS}
is not proper.
+@end defmac
-@findex REG_PARM_STACK_SPACE
-@item REG_PARM_STACK_SPACE (@var{fndecl})
+@defmac REG_PARM_STACK_SPACE (@var{fndecl})
Define this macro if functions should assume that stack space has been
allocated for arguments even when their values are passed in
registers.
This space can be allocated by the caller, or be a part of the
machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says
which.
+@end defmac
@c above is overfull. not sure what to do. --mew 5feb93 did
@c something, not sure if it looks good. --mew 10feb93
-@findex MAYBE_REG_PARM_STACK_SPACE
-@findex FINAL_REG_PARM_STACK_SPACE
-@item MAYBE_REG_PARM_STACK_SPACE
-@itemx FINAL_REG_PARM_STACK_SPACE (@var{const_size}, @var{var_size})
+@defmac MAYBE_REG_PARM_STACK_SPACE
+@defmacx FINAL_REG_PARM_STACK_SPACE (@var{const_size}, @var{var_size})
Define these macros in addition to the one above if functions might
allocate stack space for arguments even when their values are passed
in registers. These should be used when the stack space allocated
When deciding whether a called function needs such stack space, and how
much space to reserve, GCC uses these two macros instead of
@code{REG_PARM_STACK_SPACE}.
+@end defmac
-@findex OUTGOING_REG_PARM_STACK_SPACE
-@item OUTGOING_REG_PARM_STACK_SPACE
+@defmac OUTGOING_REG_PARM_STACK_SPACE
Define this if it is the responsibility of the caller to allocate the area
reserved for arguments passed in registers.
If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
whether the space for these arguments counts in the value of
@code{current_function_outgoing_args_size}.
+@end defmac
-@findex STACK_PARMS_IN_REG_PARM_AREA
-@item STACK_PARMS_IN_REG_PARM_AREA
+@defmac STACK_PARMS_IN_REG_PARM_AREA
Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the
stack parameters don't skip the area specified by it.
@c i changed this, makes more sens and it should have taken care of the
stack beyond the @code{REG_PARM_STACK_SPACE} area. Defining this macro
suppresses this behavior and causes the parameter to be passed on the
stack in its natural location.
+@end defmac
-@findex RETURN_POPS_ARGS
-@item RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size})
+@defmac RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size})
A C expression that should indicate the number of bytes of its own
arguments that a function pops on returning, or 0 if the
function pops no arguments and the caller must therefore pop them all
nothing (the caller pops all). When this convention is in use,
@var{funtype} is examined to determine whether a function takes a fixed
number of arguments.
+@end defmac
-@findex CALL_POPS_ARGS
-@item CALL_POPS_ARGS (@var{cum})
+@defmac CALL_POPS_ARGS (@var{cum})
A C expression that should indicate the number of bytes a call sequence
pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS}
when compiling a function call.
that have been passed to the function. Since this is a property of the
call site, not of the called function, @code{RETURN_POPS_ARGS} is not
appropriate.
-
-@end table
+@end defmac
@node Register Arguments
@subsection Passing Arguments in Registers
types of arguments are passed in registers or how they are arranged in
the stack.
-@table @code
-@findex FUNCTION_ARG
-@item FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
A C expression that controls whether a function argument is passed
in a register, and which register.
The value of the expression can also be a @code{parallel} RTX@. This is
used when an argument is passed in multiple locations. The mode of the
-of the @code{parallel} should be the mode of the entire argument. The
+@code{parallel} should be the mode of the entire argument. The
@code{parallel} holds any number of @code{expr_list} pairs; each one
describes where part of the argument is passed. In each
@code{expr_list} the first operand must be a @code{reg} RTX for the hard
argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is
defined, the argument will be computed in the stack and then loaded into
a register.
+@end defmac
-@findex MUST_PASS_IN_STACK
-@item MUST_PASS_IN_STACK (@var{mode}, @var{type})
+@defmac MUST_PASS_IN_STACK (@var{mode}, @var{type})
Define as a C expression that evaluates to nonzero if we do not know how
to pass TYPE solely in registers. The file @file{expr.h} defines a
definition that is usually appropriate, refer to @file{expr.h} for additional
documentation.
+@end defmac
-@findex FUNCTION_INCOMING_ARG
-@item FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
Define this macro if the target machine has ``register windows'', so
that the register in which a function sees an arguments is not
necessarily the same as the one in which the caller passed the
If @code{FUNCTION_INCOMING_ARG} is not defined, @code{FUNCTION_ARG}
serves both purposes.
+@end defmac
-@findex FUNCTION_ARG_PARTIAL_NREGS
-@item FUNCTION_ARG_PARTIAL_NREGS (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG_PARTIAL_NREGS (@var{cum}, @var{mode}, @var{type}, @var{named})
A C expression for the number of words, at the beginning of an
argument, that must be put in registers. The value must be zero for
arguments that are passed entirely in registers or that are entirely
@code{FUNCTION_ARG} for these arguments should return the first
register to be used by the caller for this argument; likewise
@code{FUNCTION_INCOMING_ARG}, for the called function.
+@end defmac
-@findex FUNCTION_ARG_PASS_BY_REFERENCE
-@item FUNCTION_ARG_PASS_BY_REFERENCE (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG_PASS_BY_REFERENCE (@var{cum}, @var{mode}, @var{type}, @var{named})
A C expression that indicates when an argument must be passed by reference.
If nonzero for an argument, a copy of that argument is made in memory and a
pointer to the argument is passed instead of the argument itself.
MUST_PASS_IN_STACK (MODE, TYPE)
@end smallexample
@c this is *still* too long. --mew 5feb93
+@end defmac
-@findex FUNCTION_ARG_CALLEE_COPIES
-@item FUNCTION_ARG_CALLEE_COPIES (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG_CALLEE_COPIES (@var{cum}, @var{mode}, @var{type}, @var{named})
If defined, a C expression that indicates when it is the called function's
responsibility to make a copy of arguments passed by invisible reference.
Normally, the caller makes a copy and passes the address of the copy to the
``live'' value. The called function must not modify this value. If it can be
determined that the value won't be modified, it need not make a copy;
otherwise a copy must be made.
+@end defmac
-@findex FUNCTION_ARG_REG_LITTLE_ENDIAN
-@item FUNCTION_ARG_REG_LITTLE_ENDIAN
-If defined TRUE on a big-endian system then structure arguments passed
-(and returned) in registers are passed in a little-endian manner instead of
-the big-endian manner. On the HP-UX IA64 and PA64 platforms structures are
-aligned differently then integral values and setting this value to true will
-allow for the special handling of structure arguments and return values.
-
-@findex CUMULATIVE_ARGS
-@item CUMULATIVE_ARGS
+@defmac CUMULATIVE_ARGS
A C type for declaring a variable that is used as the first argument of
@code{FUNCTION_ARG} and other related values. For some target machines,
the type @code{int} suffices and can hold the number of bytes of
arguments are passed on the stack, there is no need to store anything in
@code{CUMULATIVE_ARGS}; however, the data structure must exist and
should not be empty, so use @code{int}.
+@end defmac
-@findex INIT_CUMULATIVE_ARGS
-@item INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{indirect})
-A C statement (sans semicolon) for initializing the variable @var{cum}
-for the state at the beginning of the argument list. The variable has
-type @code{CUMULATIVE_ARGS}. The value of @var{fntype} is the tree node
-for the data type of the function which will receive the args, or 0
-if the args are to a compiler support library function. The value of
-@var{indirect} is nonzero when processing an indirect call, for example
-a call through a function pointer. The value of @var{indirect} is zero
-for a call to an explicitly named function, a library function call, or when
+@defmac INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{fndecl})
+A C statement (sans semicolon) for initializing the variable
+@var{cum} for the state at the beginning of the argument list. The
+variable has type @code{CUMULATIVE_ARGS}. The value of @var{fntype}
+is the tree node for the data type of the function which will receive
+the args, or 0 if the args are to a compiler support library function.
+For direct calls that are not libcalls, @var{fndecl} contain the
+declaration node of the function. @var{fndecl} is also set when
@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function
being compiled.
an ordinary C function call is being processed. Thus, each time this
macro is called, either @var{libname} or @var{fntype} is nonzero, but
never both of them at once.
+@end defmac
-@findex INIT_CUMULATIVE_LIBCALL_ARGS
-@item INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
+@defmac INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls,
it gets a @code{MODE} argument instead of @var{fntype}, that would be
@code{NULL}. @var{indirect} would always be zero, too. If this macro
is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname,
0)} is used instead.
+@end defmac
-@findex INIT_CUMULATIVE_INCOMING_ARGS
-@item INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
+@defmac INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of
finding the arguments for the function being compiled. If this macro is
undefined, @code{INIT_CUMULATIVE_ARGS} is used instead.
@code{INIT_CUMULATIVE_ARGS}.
@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe.
@c --mew 5feb93 i switched the order of the sentences. --mew 10feb93
+@end defmac
-@findex FUNCTION_ARG_ADVANCE
-@item FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named})
A C statement (sans semicolon) to update the summarizer variable
@var{cum} to advance past an argument in the argument list. The
values @var{mode}, @var{type} and @var{named} describe that argument.
This macro need not do anything if the argument in question was passed
on the stack. The compiler knows how to track the amount of stack space
used for arguments without any special help.
+@end defmac
-@findex FUNCTION_ARG_PADDING
-@item FUNCTION_ARG_PADDING (@var{mode}, @var{type})
+@defmac FUNCTION_ARG_PADDING (@var{mode}, @var{type})
If defined, a C expression which determines whether, and in which direction,
to pad out an argument with extra space. The value should be of type
@code{enum direction}: either @code{upward} to pad above the argument,
For little-endian machines, the default is to pad upward. For
big-endian machines, the default is to pad downward for an argument of
constant size shorter than an @code{int}, and upward otherwise.
+@end defmac
-@findex PAD_VARARGS_DOWN
-@item PAD_VARARGS_DOWN
+@defmac PAD_VARARGS_DOWN
If defined, a C expression which determines whether the default
implementation of va_arg will attempt to pad down before reading the
next argument, if that argument is smaller than its aligned space as
controlled by @code{PARM_BOUNDARY}. If this macro is not defined, all such
arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
+@end defmac
-@findex FUNCTION_ARG_BOUNDARY
-@item FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
+@defmac FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
If defined, a C expression that gives the alignment boundary, in bits,
of an argument with the specified mode and type. If it is not defined,
@code{PARM_BOUNDARY} is used for all arguments.
+@end defmac
-@findex FUNCTION_ARG_REGNO_P
-@item FUNCTION_ARG_REGNO_P (@var{regno})
+@defmac FUNCTION_ARG_REGNO_P (@var{regno})
A C expression that is nonzero if @var{regno} is the number of a hard
register in which function arguments are sometimes passed. This does
@emph{not} include implicit arguments such as the static chain and
the structure-value address. On many machines, no registers can be
used for this purpose since all function arguments are pushed on the
stack.
+@end defmac
+
+@defmac SPLIT_COMPLEX_ARGS
-@findex LOAD_ARGS_REVERSED
-@item LOAD_ARGS_REVERSED
+Define this macro to a nonzero value if complex function arguments
+should be split into their corresponding components. By default, GCC
+will attempt to pack complex arguments into the target's word size.
+Some ABIs require complex arguments to be split and treated as their
+individual components. For example, on AIX64, complex floats should
+be passed in a pair of floating point registers, even though a complex
+float would fit in one 64-bit floating point register.
+@end defmac
+
+@defmac LOAD_ARGS_REVERSED
If defined, the order in which arguments are loaded into their
respective argument registers is reversed so that the last
argument is loaded first. This macro only affects arguments
passed in registers.
-
-@end table
+@end defmac
@node Scalar Return
@subsection How Scalar Function Values Are Returned
This section discusses the macros that control returning scalars as
values---values that can fit in registers.
-@table @code
-@findex FUNCTION_VALUE
-@item FUNCTION_VALUE (@var{valtype}, @var{func})
+@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
A C expression to create an RTX representing the place where a
function returns a value of data type @var{valtype}. @var{valtype} is
a tree node representing a data type. Write @code{TYPE_MODE
@code{FUNCTION_VALUE} is not used for return vales with aggregate data
types, because these are returned in another way. See
@code{STRUCT_VALUE_REGNUM} and related macros, below.
+@end defmac
-@findex FUNCTION_OUTGOING_VALUE
-@item FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
+@defmac FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
Define this macro if the target machine has ``register windows''
so that the register in which a function returns its value is not
the same as the one in which the caller sees the value.
@code{FUNCTION_OUTGOING_VALUE} is not used for return vales with
aggregate data types, because these are returned in another way. See
@code{STRUCT_VALUE_REGNUM} and related macros, below.
+@end defmac
-@findex LIBCALL_VALUE
-@item LIBCALL_VALUE (@var{mode})
+@defmac LIBCALL_VALUE (@var{mode})
A C expression to create an RTX representing the place where a library
function returns a value of mode @var{mode}. If the precise function
being called is known, @var{func} is a tree node
The definition of @code{LIBRARY_VALUE} need not be concerned aggregate
data types, because none of the library functions returns such types.
+@end defmac
-@findex FUNCTION_VALUE_REGNO_P
-@item FUNCTION_VALUE_REGNO_P (@var{regno})
+@defmac FUNCTION_VALUE_REGNO_P (@var{regno})
A C expression that is nonzero if @var{regno} is the number of a hard
register in which the values of called function may come back.
If the machine has register windows, so that the caller and the called
function use different registers for the return value, this macro
should recognize only the caller's register numbers.
+@end defmac
-@findex APPLY_RESULT_SIZE
-@item APPLY_RESULT_SIZE
+@defmac APPLY_RESULT_SIZE
Define this macro if @samp{untyped_call} and @samp{untyped_return}
need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for
saving and restoring an arbitrary return value.
-@end table
+@end defmac
@node Aggregate Return
@subsection How Large Values Are Returned
This section describes how to control returning structure values in
memory.
-@table @code
-@findex RETURN_IN_MEMORY
-@item RETURN_IN_MEMORY (@var{type})
+@defmac RETURN_IN_MEMORY (@var{type})
A C expression which can inhibit the returning of certain function
values in registers, based on the type of value. A nonzero value says
to return the function value in memory, just as large structures are
Do not use this macro to indicate that structures and unions should always
be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}
to indicate this.
+@end defmac
-@findex DEFAULT_PCC_STRUCT_RETURN
-@item DEFAULT_PCC_STRUCT_RETURN
+@defmac DEFAULT_PCC_STRUCT_RETURN
Define this macro to be 1 if all structure and union return values must be
in memory. Since this results in slower code, this should be defined
only if needed for compatibility with other compilers or with an ABI@.
and union return values are decided by the @code{RETURN_IN_MEMORY} macro.
If not defined, this defaults to the value 1.
+@end defmac
-@findex STRUCT_VALUE_REGNUM
-@item STRUCT_VALUE_REGNUM
+@defmac STRUCT_VALUE_REGNUM
If the structure value address is passed in a register, then
@code{STRUCT_VALUE_REGNUM} should be the number of that register.
+@end defmac
-@findex STRUCT_VALUE
-@item STRUCT_VALUE
+@defmac STRUCT_VALUE
If the structure value address is not passed in a register, define
@code{STRUCT_VALUE} as an expression returning an RTX for the place
where the address is passed. If it returns 0, the address is passed as
an ``invisible'' first argument.
+@end defmac
-@findex STRUCT_VALUE_INCOMING_REGNUM
-@item STRUCT_VALUE_INCOMING_REGNUM
+@defmac STRUCT_VALUE_INCOMING_REGNUM
On some architectures the place where the structure value address
is found by the called function is not the same place that the
caller put it. This can be due to register windows, or it could
If the incoming location of the structure value address is in a
register, define this macro as the register number.
+@end defmac
-@findex STRUCT_VALUE_INCOMING
-@item STRUCT_VALUE_INCOMING
+@defmac STRUCT_VALUE_INCOMING
If the incoming location is not a register, then you should define
@code{STRUCT_VALUE_INCOMING} as an expression for an RTX for where the
called function should find the value. If it should find the value on
the stack, define this to create a @code{mem} which refers to the frame
pointer. A definition of 0 means that the address is passed as an
``invisible'' first argument.
+@end defmac
-@findex PCC_STATIC_STRUCT_RETURN
-@item PCC_STATIC_STRUCT_RETURN
+@defmac PCC_STATIC_STRUCT_RETURN
Define this macro if the usual system convention on the target machine
for returning structures and unions is for the called function to return
the address of a static variable containing the value.
This macro has effect in @option{-fpcc-struct-return} mode, but it does
nothing when you use @option{-freg-struct-return} mode.
-@end table
+@end defmac
@node Caller Saves
@subsection Caller-Saves Register Allocation
makes it possible to use call-clobbered registers to hold variables that
must live across calls.
-@table @code
-@findex DEFAULT_CALLER_SAVES
-@item DEFAULT_CALLER_SAVES
+@defmac DEFAULT_CALLER_SAVES
Define this macro if function calls on the target machine do not preserve
any registers; in other words, if @code{CALL_USED_REGISTERS} has 1
for all registers. When defined, this macro enables @option{-fcaller-saves}
by default for all optimization levels. It has no effect for optimization
levels 2 and higher, where @option{-fcaller-saves} is the default.
+@end defmac
-@findex CALLER_SAVE_PROFITABLE
-@item CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
+@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
A C expression to determine whether it is worthwhile to consider placing
a pseudo-register in a call-clobbered hard register and saving and
restoring it around each function call. The expression should be 1 when
If you don't define this macro, a default is used which is good on most
machines: @code{4 * @var{calls} < @var{refs}}.
+@end defmac
-@findex HARD_REGNO_CALLER_SAVE_MODE
-@item HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
+@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
A C expression specifying which mode is required for saving @var{nregs}
of a pseudo-register in call-clobbered hard register @var{regno}. If
@var{regno} is unsuitable for caller save, @code{VOIDmode} should be
returned. For most machines this macro need not be defined since GCC
will select the smallest suitable mode.
-@end table
+@end defmac
@node Function Entry
@subsection Function Entry and Exit
@c tell? --mew 5feb93
@end deftypefn
-@table @code
-
@itemize @bullet
@item
@findex current_function_pretend_args_size
The C variable @code{current_function_is_leaf} is nonzero for such a
function.
-@findex EXIT_IGNORE_STACK
-@item EXIT_IGNORE_STACK
+@defmac EXIT_IGNORE_STACK
Define this macro as a C expression that is nonzero if the return
instruction or the function epilogue ignores the value of the stack
pointer; in other words, if it is safe to delete an instruction to
frame pointers are maintained. It is never safe to delete a final
stack adjustment in a function that has no frame pointer, and the
compiler knows this regardless of @code{EXIT_IGNORE_STACK}.
+@end defmac
-@findex EPILOGUE_USES
-@item EPILOGUE_USES (@var{regno})
+@defmac EPILOGUE_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the epilogue or the @samp{return} pattern. The stack and frame
pointer registers are already be assumed to be used as needed.
+@end defmac
-@findex EH_USES
-@item EH_USES (@var{regno})
+@defmac EH_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the exception handling mechanism, and so should be considered live
on entry to an exception edge.
+@end defmac
-@findex DELAY_SLOTS_FOR_EPILOGUE
-@item DELAY_SLOTS_FOR_EPILOGUE
+@defmac DELAY_SLOTS_FOR_EPILOGUE
Define this macro if the function epilogue contains delay slots to which
instructions from the rest of the function can be ``moved''. The
definition should be a C expression whose value is an integer
representing the number of delay slots there.
+@end defmac
-@findex ELIGIBLE_FOR_EPILOGUE_DELAY
-@item ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
+@defmac ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
A C expression that returns 1 if @var{insn} can be placed in delay
slot number @var{n} of the epilogue.
You need not define this macro if you did not define
@code{DELAY_SLOTS_FOR_EPILOGUE}.
+@end defmac
-@findex ASM_OUTPUT_MI_THUNK
-@item ASM_OUTPUT_MI_THUNK (@var{file}, @var{thunk_fndecl}, @var{delta}, @var{function})
-A C compound statement that outputs the assembler code for a thunk
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_MI_THUNK (FILE *@var{file}, tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, tree @var{function})
+A function that outputs the assembler code for a thunk
function, used to implement C++ virtual function calls with multiple
inheritance. The thunk acts as a wrapper around a virtual function,
adjusting the implicit object parameter before handing control off to
front end will generate a less efficient heavyweight thunk that calls
@var{function} instead of jumping to it. The generic approach does
not support varargs.
-@end table
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_MI_VCALL_THUNK (FILE *@var{file}, tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, int @var{vcall_offset}, tree @var{function})
+A function like @code{TARGET_ASM_OUTPUT_MI_THUNK}, except that if
+@var{vcall_offset} is nonzero, an additional adjustment should be made
+after adding @code{delta}. In particular, if @var{p} is the
+adjusted pointer, the following adjustment should be made:
+
+@example
+p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]
+@end example
+
+@noindent
+If this function is defined, it will always be used in place of
+@code{TARGET_ASM_OUTPUT_MI_THUNK}.
+@end deftypefn
@node Profiling
@subsection Generating Code for Profiling
These macros will help you generate code for profiling.
-@table @code
-@findex FUNCTION_PROFILER
-@item FUNCTION_PROFILER (@var{file}, @var{labelno})
+@defmac FUNCTION_PROFILER (@var{file}, @var{labelno})
A C statement or compound statement to output to @var{file} some
assembler code to call the profiling subroutine @code{mcount}.
variable to be loaded into some register. The name of this variable is
@samp{LP} followed by the number @var{labelno}, so you would generate
the name using @samp{LP%d} in a @code{fprintf}.
+@end defmac
-@findex PROFILE_HOOK
-@item PROFILE_HOOK
+@defmac PROFILE_HOOK
A C statement or compound statement to output to @var{file} some assembly
code to call the profiling subroutine @code{mcount} even the target does
not support profiling.
+@end defmac
-@findex NO_PROFILE_COUNTERS
-@item NO_PROFILE_COUNTERS
+@defmac NO_PROFILE_COUNTERS
Define this macro if the @code{mcount} subroutine on your system does
not need a counter variable allocated for each function. This is true
for almost all modern implementations. If you define this macro, you
must not use the @var{labelno} argument to @code{FUNCTION_PROFILER}.
+@end defmac
-@findex PROFILE_BEFORE_PROLOGUE
-@item PROFILE_BEFORE_PROLOGUE
+@defmac PROFILE_BEFORE_PROLOGUE
Define this macro if the code for function profiling should come before
the function prologue. Normally, the profiling code comes after.
-@end table
+@end defmac
@node Tail Calls
@subsection Permitting tail calls
@cindex tail calls
-@table @code
-@findex FUNCTION_OK_FOR_SIBCALL
-@item FUNCTION_OK_FOR_SIBCALL (@var{decl})
-A C expression that evaluates to true if it is ok to perform a sibling
-call to @var{decl} from the current function.
+@deftypefn {Target Hook} bool TARGET_FUNCTION_OK_FOR_SIBCALL (tree @var{decl}, tree @var{exp})
+True if it is ok to do sibling call optimization for the specified
+call expression @var{exp}. @var{decl} will be the called function,
+or @code{NULL} if this is an indirect call.
It is not uncommon for limitations of calling conventions to prevent
tail calls to functions outside the current unit of translation, or
-during PIC compilation. Use this macro to enforce these restrictions,
+during PIC compilation. The hook is used to enforce these restrictions,
as the @code{sibcall} md pattern can not fail, or fall over to a
-``normal'' call.
-@end table
+``normal'' call. The criteria for successful sibling call optimization
+may vary greatly between different architectures.
+@end deftypefn
@node Varargs
@section Implementing the Varargs Macros
the end of the named arguments is with the built-in functions described
below.
-@table @code
-@findex __builtin_saveregs
-@item __builtin_saveregs ()
+@defmac __builtin_saveregs ()
Use this built-in function to save the argument registers in memory so
that the varargs mechanism can access them. Both ISO and traditional
versions of @code{va_start} must use @code{__builtin_saveregs}, unless
to use them for its own purposes.
@c i rewrote the first sentence above to fix an overfull hbox. --mew
@c 10feb93
+@end defmac
-@findex __builtin_args_info
-@item __builtin_args_info (@var{category})
+@defmac __builtin_args_info (@var{category})
Use this built-in function to find the first anonymous arguments in
registers.
value in the @code{va_list} object. This is because @code{va_list} will
have to update the values, and there is no way to alter the
values accessed by @code{__builtin_args_info}.
+@end defmac
-@findex __builtin_next_arg
-@item __builtin_next_arg (@var{lastarg})
+@defmac __builtin_next_arg (@var{lastarg})
This is the equivalent of @code{__builtin_args_info}, for stack
arguments. It returns the address of the first anonymous stack
argument, as type @code{void *}. If @code{ARGS_GROW_DOWNWARD}, it
fetching arguments from the stack. Also use it in @code{va_start} to
verify that the second parameter @var{lastarg} is the last named argument
of the current function.
+@end defmac
-@findex __builtin_classify_type
-@item __builtin_classify_type (@var{object})
+@defmac __builtin_classify_type (@var{object})
Since each machine has its own conventions for which data types are
passed in which kind of register, your implementation of @code{va_arg}
has to embody these conventions. The easiest way to categorize the
The file @file{typeclass.h} defines an enumeration that you can use to
interpret the values of @code{__builtin_classify_type}.
-@end table
+@end defmac
These machine description macros help implement varargs:
-@table @code
-@findex EXPAND_BUILTIN_SAVEREGS
-@item EXPAND_BUILTIN_SAVEREGS ()
+@defmac EXPAND_BUILTIN_SAVEREGS ()
If defined, is a C expression that produces the machine-specific code
for a call to @code{__builtin_saveregs}. This code will be moved to the
very beginning of the function, before any parameter access are made.
The return value of this function should be an RTX that contains the
value to use as the return of @code{__builtin_saveregs}.
+@end defmac
-@findex SETUP_INCOMING_VARARGS
-@item SETUP_INCOMING_VARARGS (@var{args_so_far}, @var{mode}, @var{type}, @var{pretend_args_size}, @var{second_time})
+@defmac SETUP_INCOMING_VARARGS (@var{args_so_far}, @var{mode}, @var{type}, @var{pretend_args_size}, @var{second_time})
This macro offers an alternative to using @code{__builtin_saveregs} and
defining the macro @code{EXPAND_BUILTIN_SAVEREGS}. Use it to store the
anonymous register arguments into the stack so that all the arguments
happens for an inline function, which is not actually compiled until the
end of the source file. The macro @code{SETUP_INCOMING_VARARGS} should
not generate any instructions in this case.
+@end defmac
-@findex STRICT_ARGUMENT_NAMING
-@item STRICT_ARGUMENT_NAMING
+@defmac STRICT_ARGUMENT_NAMING
Define this macro to be a nonzero value if the location where a function
argument is passed depends on whether or not it is a named argument.
are treated as named.
You need not define this macro if it always returns zero.
+@end defmac
-@findex PRETEND_OUTGOING_VARARGS_NAMED
-@item PRETEND_OUTGOING_VARARGS_NAMED
+@defmac PRETEND_OUTGOING_VARARGS_NAMED
If you need to conditionally change ABIs so that one works with
@code{SETUP_INCOMING_VARARGS}, but the other works like neither
@code{SETUP_INCOMING_VARARGS} nor @code{STRICT_ARGUMENT_NAMING} was
defined, then define this macro to return nonzero if
@code{SETUP_INCOMING_VARARGS} is used, zero otherwise.
Otherwise, you should not define this macro.
-@end table
+@end defmac
@node Trampolines
@section Trampolines for Nested Functions
may be necessary to take out pieces of the address and store them
separately.
-@table @code
-@findex TRAMPOLINE_TEMPLATE
-@item TRAMPOLINE_TEMPLATE (@var{file})
+@defmac TRAMPOLINE_TEMPLATE (@var{file})
A C statement to output, on the stream @var{file}, assembler code for a
block of data that contains the constant parts of a trampoline. This
code should not include a label---the label is taken care of
for the target. Do not define this macro on systems where the block move
code to copy the trampoline into place would be larger than the code
to generate it on the spot.
+@end defmac
-@findex TRAMPOLINE_SECTION
-@item TRAMPOLINE_SECTION
+@defmac TRAMPOLINE_SECTION
The name of a subroutine to switch to the section in which the
trampoline template is to be placed (@pxref{Sections}). The default is
a value of @samp{readonly_data_section}, which places the trampoline in
the section containing read-only data.
+@end defmac
-@findex TRAMPOLINE_SIZE
-@item TRAMPOLINE_SIZE
+@defmac TRAMPOLINE_SIZE
A C expression for the size in bytes of the trampoline, as an integer.
+@end defmac
-@findex TRAMPOLINE_ALIGNMENT
-@item TRAMPOLINE_ALIGNMENT
+@defmac TRAMPOLINE_ALIGNMENT
Alignment required for trampolines, in bits.
If you don't define this macro, the value of @code{BIGGEST_ALIGNMENT}
is used for aligning trampolines.
+@end defmac
-@findex INITIALIZE_TRAMPOLINE
-@item INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain})
+@defmac INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain})
A C statement to initialize the variable parts of a trampoline.
@var{addr} is an RTX for the address of the trampoline; @var{fnaddr} is
an RTX for the address of the nested function; @var{static_chain} is an
RTX for the static chain value that should be passed to the function
when it is called.
+@end defmac
-@findex TRAMPOLINE_ADJUST_ADDRESS
-@item TRAMPOLINE_ADJUST_ADDRESS (@var{addr})
+@defmac TRAMPOLINE_ADJUST_ADDRESS (@var{addr})
A C statement that should perform any machine-specific adjustment in
the address of the trampoline. Its argument contains the address that
was passed to @code{INITIALIZE_TRAMPOLINE}. In case the address to be
@var{addr}. If this macro is not defined, @var{addr} will be used for
function calls.
-@findex ALLOCATE_TRAMPOLINE
-@item ALLOCATE_TRAMPOLINE (@var{fp})
-A C expression to allocate run-time space for a trampoline. The
-expression value should be an RTX representing a memory reference to the
-space for the trampoline.
-
@cindex @code{TARGET_ASM_FUNCTION_EPILOGUE} and trampolines
@cindex @code{TARGET_ASM_FUNCTION_PROLOGUE} and trampolines
If this macro is not defined, by default the trampoline is allocated as
@var{fp} points to a data structure, a @code{struct function}, which
describes the compilation status of the immediate containing function of
-the function which the trampoline is for. Normally (when
-@code{ALLOCATE_TRAMPOLINE} is not defined), the stack slot for the
+the function which the trampoline is for. The stack slot for the
trampoline is in the stack frame of this containing function. Other
allocation strategies probably must do something analogous with this
information.
-@end table
+@end defmac
Implementing trampolines is difficult on many machines because they have
separate instruction and data caches. Writing into a stack location
latter makes initialization faster.
To clear the instruction cache when a trampoline is initialized, define
-the following macros which describe the shape of the cache.
-
-@table @code
-@findex INSN_CACHE_SIZE
-@item INSN_CACHE_SIZE
-The total size in bytes of the cache.
-
-@findex INSN_CACHE_LINE_WIDTH
-@item INSN_CACHE_LINE_WIDTH
-The length in bytes of each cache line. The cache is divided into cache
-lines which are disjoint slots, each holding a contiguous chunk of data
-fetched from memory. Each time data is brought into the cache, an
-entire line is read at once. The data loaded into a cache line is
-always aligned on a boundary equal to the line size.
-
-@findex INSN_CACHE_DEPTH
-@item INSN_CACHE_DEPTH
-The number of alternative cache lines that can hold any particular memory
-location.
-@end table
-
-Alternatively, if the machine has system calls or instructions to clear
-the instruction cache directly, you can define the following macro.
-
-@table @code
-@findex CLEAR_INSN_CACHE
-@item CLEAR_INSN_CACHE (@var{beg}, @var{end})
+the following macro.
+
+@defmac CLEAR_INSN_CACHE (@var{beg}, @var{end})
If defined, expands to a C expression clearing the @emph{instruction
-cache} in the specified interval. If it is not defined, and the macro
-@code{INSN_CACHE_SIZE} is defined, some generic code is generated to clear the
-cache. The definition of this macro would typically be a series of
-@code{asm} statements. Both @var{beg} and @var{end} are both pointer
-expressions.
-@end table
+cache} in the specified interval. The definition of this macro would
+typically be a series of @code{asm} statements. Both @var{beg} and
+@var{end} are both pointer expressions.
+@end defmac
To use a standard subroutine, define the following macro. In addition,
you must make sure that the instructions in a trampoline fill an entire
beginning of the trampoline code is always aligned at the same point in
its cache line. Look in @file{m68k.h} as a guide.
-@table @code
-@findex TRANSFER_FROM_TRAMPOLINE
-@item TRANSFER_FROM_TRAMPOLINE
+@defmac TRANSFER_FROM_TRAMPOLINE
Define this macro if trampolines need a special subroutine to do their
work. The macro should expand to a series of @code{asm} statements
which will be compiled with GCC@. They go in a library function named
statement to generate an assembler label, and another to make the label
global. Then trampolines can use that label to jump directly to your
special assembler code.
-@end table
+@end defmac
@node Library Calls
@section Implicit Calls to Library Routines
@c prevent bad page break with this line
Here is an explanation of implicit calls to library routines.
-@table @code
-@findex MULSI3_LIBCALL
-@item MULSI3_LIBCALL
+@defmac MULSI3_LIBCALL
A C string constant giving the name of the function to call for
multiplication of one signed full-word by another. If you do not
define this macro, the default name is used, which is @code{__mulsi3},
a function defined in @file{libgcc.a}.
+@end defmac
-@findex DIVSI3_LIBCALL
-@item DIVSI3_LIBCALL
+@defmac DIVSI3_LIBCALL
A C string constant giving the name of the function to call for
division of one signed full-word by another. If you do not define
this macro, the default name is used, which is @code{__divsi3}, a
function defined in @file{libgcc.a}.
+@end defmac
-@findex UDIVSI3_LIBCALL
-@item UDIVSI3_LIBCALL
+@defmac UDIVSI3_LIBCALL
A C string constant giving the name of the function to call for
division of one unsigned full-word by another. If you do not define
this macro, the default name is used, which is @code{__udivsi3}, a
function defined in @file{libgcc.a}.
+@end defmac
-@findex MODSI3_LIBCALL
-@item MODSI3_LIBCALL
+@defmac MODSI3_LIBCALL
A C string constant giving the name of the function to call for the
remainder in division of one signed full-word by another. If you do
not define this macro, the default name is used, which is
@code{__modsi3}, a function defined in @file{libgcc.a}.
+@end defmac
-@findex UMODSI3_LIBCALL
-@item UMODSI3_LIBCALL
+@defmac UMODSI3_LIBCALL
A C string constant giving the name of the function to call for the
remainder in division of one unsigned full-word by another. If you do
not define this macro, the default name is used, which is
@code{__umodsi3}, a function defined in @file{libgcc.a}.
+@end defmac
-@findex MULDI3_LIBCALL
-@item MULDI3_LIBCALL
+@defmac MULDI3_LIBCALL
A C string constant giving the name of the function to call for
multiplication of one signed double-word by another. If you do not
define this macro, the default name is used, which is @code{__muldi3},
a function defined in @file{libgcc.a}.
+@end defmac
-@findex DIVDI3_LIBCALL
-@item DIVDI3_LIBCALL
+@defmac DIVDI3_LIBCALL
A C string constant giving the name of the function to call for
division of one signed double-word by another. If you do not define
this macro, the default name is used, which is @code{__divdi3}, a
function defined in @file{libgcc.a}.
+@end defmac
-@findex UDIVDI3_LIBCALL
-@item UDIVDI3_LIBCALL
+@defmac UDIVDI3_LIBCALL
A C string constant giving the name of the function to call for
division of one unsigned full-word by another. If you do not define
this macro, the default name is used, which is @code{__udivdi3}, a
function defined in @file{libgcc.a}.
+@end defmac
-@findex MODDI3_LIBCALL
-@item MODDI3_LIBCALL
+@defmac MODDI3_LIBCALL
A C string constant giving the name of the function to call for the
remainder in division of one signed double-word by another. If you do
not define this macro, the default name is used, which is
@code{__moddi3}, a function defined in @file{libgcc.a}.
+@end defmac
-@findex UMODDI3_LIBCALL
-@item UMODDI3_LIBCALL
+@defmac UMODDI3_LIBCALL
A C string constant giving the name of the function to call for the
remainder in division of one unsigned full-word by another. If you do
not define this macro, the default name is used, which is
@code{__umoddi3}, a function defined in @file{libgcc.a}.
+@end defmac
-@findex DECLARE_LIBRARY_RENAMES
-@item DECLARE_LIBRARY_RENAMES
+@defmac DECLARE_LIBRARY_RENAMES
This macro, if defined, should expand to a piece of C code that will get
expanded when compiling functions for libgcc.a. It can be used to
provide alternate names for gcc's internal library functions if there
are ABI-mandated names that the compiler should provide.
+@end defmac
-@findex INIT_TARGET_OPTABS
-@item INIT_TARGET_OPTABS
+@defmac INIT_TARGET_OPTABS
Define this macro as a C statement that declares additional library
routines renames existing ones. @code{init_optabs} calls this macro after
initializing all the normal library routines.
+@end defmac
-@findex FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
-@item FLOAT_LIB_COMPARE_RETURNS_BOOL
+@defmac FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
Define this macro as a C statement that returns nonzero if a call to
the floating point comparison library function will return a boolean
value that indicates the result of the comparison. It should return
zero if one of gcc's own libgcc functions is called.
Most ports don't need to define this macro.
+@end defmac
-@findex TARGET_EDOM
@cindex @code{EDOM}, implicit usage
-@item TARGET_EDOM
+@findex matherr
+@defmac TARGET_EDOM
The value of @code{EDOM} on the target machine, as a C integer constant
expression. If you don't define this macro, GCC does not attempt to
deposit the value of @code{EDOM} into @code{errno} directly. Look in
error. If mathematical functions on your system use @code{matherr} when
there is an error, then you should leave @code{TARGET_EDOM} undefined so
that @code{matherr} is used normally.
+@end defmac
-@findex GEN_ERRNO_RTX
@cindex @code{errno}, implicit usage
-@item GEN_ERRNO_RTX
+@defmac GEN_ERRNO_RTX
Define this macro as a C expression to create an rtl expression that
refers to the global ``variable'' @code{errno}. (On certain systems,
@code{errno} may not actually be a variable.) If you don't define this
macro, a reasonable default is used.
+@end defmac
-@findex TARGET_MEM_FUNCTIONS
@cindex @code{bcopy}, implicit usage
@cindex @code{memcpy}, implicit usage
@cindex @code{memmove}, implicit usage
@cindex @code{bzero}, implicit usage
@cindex @code{memset}, implicit usage
-@item TARGET_MEM_FUNCTIONS
+@defmac TARGET_MEM_FUNCTIONS
Define this macro if GCC should generate calls to the ISO C
(and System V) library functions @code{memcpy}, @code{memmove} and
@code{memset} rather than the BSD functions @code{bcopy} and @code{bzero}.
+@end defmac
-@findex LIBGCC_NEEDS_DOUBLE
-@item LIBGCC_NEEDS_DOUBLE
+@cindex C99 math functions, implicit usage
+@defmac TARGET_C99_FUNCTIONS
+When this macro is nonzero, GCC will implicitly optimize @code{sin} calls into
+@code{sinf} and similarly for other functions defined by C99 standard. The
+default is nonzero that should be proper value for most modern systems, however
+number of existing systems lacks support for these functions in the runtime so
+they needs this macro to be redefined to 0.
+@end defmac
+
+@defmac LIBGCC_NEEDS_DOUBLE
Define this macro if @code{float} arguments cannot be passed to library
routines (so they must be converted to @code{double}). This macro
affects both how library calls are generated and how the library
routines in @file{libgcc.a} accept their arguments. It is useful on
machines where floating and fixed point arguments are passed
differently, such as the i860.
+@end defmac
-@findex NEXT_OBJC_RUNTIME
-@item NEXT_OBJC_RUNTIME
+@defmac NEXT_OBJC_RUNTIME
Define this macro to generate code for Objective-C message sending using
the calling convention of the NeXT system. This calling convention
involves passing the object, the selector and the method arguments all
The default calling convention passes just the object and the selector
to the lookup function, which returns a pointer to the method.
-@end table
+@end defmac
@node Addressing Modes
@section Addressing Modes
@c prevent bad page break with this line
This is about addressing modes.
-@table @code
-@findex HAVE_PRE_INCREMENT
-@findex HAVE_PRE_DECREMENT
-@findex HAVE_POST_INCREMENT
-@findex HAVE_POST_DECREMENT
-@item HAVE_PRE_INCREMENT
-@itemx HAVE_PRE_DECREMENT
-@itemx HAVE_POST_INCREMENT
-@itemx HAVE_POST_DECREMENT
+@defmac HAVE_PRE_INCREMENT
+@defmacx HAVE_PRE_DECREMENT
+@defmacx HAVE_POST_INCREMENT
+@defmacx HAVE_POST_DECREMENT
A C expression that is nonzero if the machine supports pre-increment,
pre-decrement, post-increment, or post-decrement addressing respectively.
+@end defmac
-@findex HAVE_POST_MODIFY_DISP
-@findex HAVE_PRE_MODIFY_DISP
-@item HAVE_PRE_MODIFY_DISP
-@itemx HAVE_POST_MODIFY_DISP
+@defmac HAVE_PRE_MODIFY_DISP
+@defmacx HAVE_POST_MODIFY_DISP
A C expression that is nonzero if the machine supports pre- or
post-address side-effect generation involving constants other than
the size of the memory operand.
+@end defmac
-@findex HAVE_POST_MODIFY_REG
-@findex HAVE_PRE_MODIFY_REG
-@item HAVE_PRE_MODIFY_REG
-@itemx HAVE_POST_MODIFY_REG
+@defmac HAVE_PRE_MODIFY_REG
+@defmacx HAVE_POST_MODIFY_REG
A C expression that is nonzero if the machine supports pre- or
post-address side-effect generation involving a register displacement.
+@end defmac
-@findex CONSTANT_ADDRESS_P
-@item CONSTANT_ADDRESS_P (@var{x})
+@defmac CONSTANT_ADDRESS_P (@var{x})
A C expression that is 1 if the RTX @var{x} is a constant which
is a valid address. On most machines, this can be defined as
@code{CONSTANT_P (@var{x})}, but a few machines are more restrictive
in which constant addresses are supported.
+@end defmac
-@findex CONSTANT_P
-@code{CONSTANT_P} accepts integer-values expressions whose values are
-not explicitly known, such as @code{symbol_ref}, @code{label_ref}, and
-@code{high} expressions and @code{const} arithmetic expressions, in
-addition to @code{const_int} and @code{const_double} expressions.
+@defmac CONSTANT_P (@var{x})
+@code{CONSTANT_P}, which is defined by target-independent code,
+accepts integer-values expressions whose values are not explicitly
+known, such as @code{symbol_ref}, @code{label_ref}, and @code{high}
+expressions and @code{const} arithmetic expressions, in addition to
+@code{const_int} and @code{const_double} expressions.
+@end defmac
-@findex MAX_REGS_PER_ADDRESS
-@item MAX_REGS_PER_ADDRESS
+@defmac MAX_REGS_PER_ADDRESS
A number, the maximum number of registers that can appear in a valid
memory address. Note that it is up to you to specify a value equal to
the maximum number that @code{GO_IF_LEGITIMATE_ADDRESS} would ever
accept.
+@end defmac
-@findex GO_IF_LEGITIMATE_ADDRESS
-@item GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
+@defmac GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
A C compound statement with a conditional @code{goto @var{label};}
executed if @var{x} (an RTX) is a legitimate memory address on the
target machine for a memory operand of mode @var{mode}.
@code{const}, you will have to look inside it to find the
@code{symbol_ref} in order to determine the section. @xref{Assembler
Format}.
+@end defmac
-@findex saveable_obstack
-The best way to modify the name string is by adding text to the
-beginning, with suitable punctuation to prevent any ambiguity. Allocate
-the new name in @code{saveable_obstack}. You will have to modify
-@code{ASM_OUTPUT_LABELREF} to remove and decode the added text and
-output the name accordingly, and define @code{TARGET_STRIP_NAME_ENCODING}
-to access the original name string.
-
-You can check the information stored here into the @code{symbol_ref} in
-the definitions of the macros @code{GO_IF_LEGITIMATE_ADDRESS} and
-@code{PRINT_OPERAND_ADDRESS}.
-
-@findex REG_OK_FOR_BASE_P
-@item REG_OK_FOR_BASE_P (@var{x})
+@defmac REG_OK_FOR_BASE_P (@var{x})
A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
RTX) is valid for use as a base register. For hard registers, it
should always accept those which the hardware permits and reject the
controlled by @code{REG_OK_STRICT} as described above. This usually
requires two variant definitions, of which @code{REG_OK_STRICT}
controls the one actually used.
+@end defmac
-@findex REG_MODE_OK_FOR_BASE_P
-@item REG_MODE_OK_FOR_BASE_P (@var{x}, @var{mode})
+@defmac REG_MODE_OK_FOR_BASE_P (@var{x}, @var{mode})
A C expression that is just like @code{REG_OK_FOR_BASE_P}, except that
that expression may examine the mode of the memory reference in
@var{mode}. You should define this macro if the mode of the memory
reference affects whether a register may be used as a base register. If
you define this macro, the compiler will use it instead of
@code{REG_OK_FOR_BASE_P}.
+@end defmac
-@findex REG_OK_FOR_INDEX_P
-@item REG_OK_FOR_INDEX_P (@var{x})
+@defmac REG_OK_FOR_INDEX_P (@var{x})
A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
RTX) is valid for use as an index register.
may serve in each capacity. The compiler will try both labelings,
looking for one that is valid, and will reload one or both registers
only if neither labeling works.
+@end defmac
-@findex FIND_BASE_TERM
-@item FIND_BASE_TERM (@var{x})
+@defmac FIND_BASE_TERM (@var{x})
A C expression to determine the base term of address @var{x}.
This macro is used in only one place: `find_base_term' in alias.c.
The typical use of this macro is to handle addresses containing
a label_ref or symbol_ref within an UNSPEC@.
+@end defmac
-@findex LEGITIMIZE_ADDRESS
-@item LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win})
+@defmac LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win})
A C compound statement that attempts to replace @var{x} with a valid
memory address for an operand of mode @var{mode}. @var{win} will be a
C statement label elsewhere in the code; the macro definition may use
address. The compiler has standard ways of doing so in all cases. In
fact, it is safe for this macro to do nothing. But often a
machine-dependent strategy can generate better code.
+@end defmac
-@findex LEGITIMIZE_RELOAD_ADDRESS
-@item LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
+@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
A C compound statement that attempts to replace @var{x}, which is an address
that needs reloading, with a valid memory address for an operand of mode
@var{mode}. @var{win} will be a C statement label elsewhere in the code.
top level, you'll need to replace first the top level.
It is not necessary for this macro to come up with a legitimate
address; but often a machine-dependent strategy can generate better code.
+@end defmac
-@findex GO_IF_MODE_DEPENDENT_ADDRESS
-@item GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label})
+@defmac GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label})
A C statement or compound statement with a conditional @code{goto
@var{label};} executed if memory address @var{x} (an RTX) can have
different meanings depending on the machine mode of the memory
addresses. Many RISC machines have no mode-dependent addresses.
You may assume that @var{addr} is a valid address for the machine.
+@end defmac
-@findex LEGITIMATE_CONSTANT_P
-@item LEGITIMATE_CONSTANT_P (@var{x})
+@defmac LEGITIMATE_CONSTANT_P (@var{x})
A C expression that is nonzero if @var{x} is a legitimate constant for
an immediate operand on the target machine. You can assume that
@var{x} satisfies @code{CONSTANT_P}, so you need not check this. In fact,
@samp{1} is a suitable definition for this macro on machines where
anything @code{CONSTANT_P} is valid.
-@end table
+@end defmac
@node Condition Code
@section Condition Code Status
description header file. It can also add additional machine-specific
information by defining @code{CC_STATUS_MDEP}.
-@table @code
-@findex CC_STATUS_MDEP
-@item CC_STATUS_MDEP
+@defmac CC_STATUS_MDEP
C code for a data type which is used for declaring the @code{mdep}
component of @code{cc_status}. It defaults to @code{int}.
This macro is not used on machines that do not use @code{cc0}.
+@end defmac
-@findex CC_STATUS_MDEP_INIT
-@item CC_STATUS_MDEP_INIT
+@defmac CC_STATUS_MDEP_INIT
A C expression to initialize the @code{mdep} field to ``empty''.
The default definition does nothing, since most machines don't use
the field anyway. If you want to use the field, you should probably
define this macro to initialize it.
This macro is not used on machines that do not use @code{cc0}.
+@end defmac
-@findex NOTICE_UPDATE_CC
-@item NOTICE_UPDATE_CC (@var{exp}, @var{insn})
+@defmac NOTICE_UPDATE_CC (@var{exp}, @var{insn})
A C compound statement to set the components of @code{cc_status}
appropriately for an insn @var{insn} whose body is @var{exp}. It is
this macro's responsibility to recognize insns that set the condition
that looks at an attribute (@pxref{Insn Attributes}) named, for example,
@samp{cc}. This avoids having detailed information about patterns in
two places, the @file{md} file and in @code{NOTICE_UPDATE_CC}.
+@end defmac
-@findex EXTRA_CC_MODES
-@item EXTRA_CC_MODES
+@defmac EXTRA_CC_MODES
Condition codes are represented in registers by machine modes of class
@code{MODE_CC}. By default, there is just one mode, @code{CCmode}, with
this class. If you need more such modes, create a file named
When you create this file, the macro @code{EXTRA_CC_MODES} is
automatically defined by @command{configure}, with value @samp{1}.
+@end defmac
-@findex SELECT_CC_MODE
-@item SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
+@defmac SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
Returns a mode from class @code{MODE_CC} to be used when comparison
operation code @var{op} is applied to rtx @var{x} and @var{y}. For
example, on the SPARC, @code{SELECT_CC_MODE} is defined as (see
@end smallexample
You need not define this macro if @code{EXTRA_CC_MODES} is not defined.
+@end defmac
-@findex CANONICALIZE_COMPARISON
-@item CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
+@defmac CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
On some machines not all possible comparisons are defined, but you can
convert an invalid comparison into a valid one. For example, the Alpha
does not have a @code{GT} comparison, but you can use an @code{LT}
You need not define this macro if it would never change the comparison
code or operands.
+@end defmac
-@findex REVERSIBLE_CC_MODE
-@item REVERSIBLE_CC_MODE (@var{mode})
+@defmac REVERSIBLE_CC_MODE (@var{mode})
A C expression whose value is one if it is always safe to reverse a
comparison whose mode is @var{mode}. If @code{SELECT_CC_MODE}
can ever return @var{mode} for a floating-point inequality comparison,
@smallexample
#define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode)
@end smallexample
+@end defmac
-@findex REVERSE_CONDITION (@var{code}, @var{mode})
+@defmac REVERSE_CONDITION (@var{code}, @var{mode})
A C expression whose value is reversed condition code of the @var{code} for
comparison done in CC_MODE @var{mode}. The macro is used only in case
@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case
((MODE) != CCFPmode ? reverse_condition (CODE) \
: reverse_condition_maybe_unordered (CODE))
@end smallexample
+@end defmac
-@findex REVERSE_CONDEXEC_PREDICATES_P
-@item REVERSE_CONDEXEC_PREDICATES_P (@var{code1}, @var{code2})
+@defmac REVERSE_CONDEXEC_PREDICATES_P (@var{code1}, @var{code2})
A C expression that returns true if the conditional execution predicate
@var{code1} is the inverse of @var{code2} and vice versa. Define this to
return 0 if the target has conditional execution predicates that cannot be
#define REVERSE_CONDEXEC_PREDICATES_P (x, y) \
((x) == reverse_condition (y))
@end smallexample
-
-@end table
+@end defmac
@node Costs
@section Describing Relative Costs of Operations
These macros let you describe the relative speed of various operations
on the target machine.
-@table @code
-@findex CONST_COSTS
-@item CONST_COSTS (@var{x}, @var{code}, @var{outer_code})
-A part of a C @code{switch} statement that describes the relative costs
-of constant RTL expressions. It must contain @code{case} labels for
-expression codes @code{const_int}, @code{const}, @code{symbol_ref},
-@code{label_ref} and @code{const_double}. Each case must ultimately
-reach a @code{return} statement to return the relative cost of the use
-of that kind of constant value in an expression. The cost may depend on
-the precise value of the constant, which is available for examination in
-@var{x}, and the rtx code of the expression in which it is contained,
-found in @var{outer_code}.
-
-@var{code} is the expression code---redundant, since it can be
-obtained with @code{GET_CODE (@var{x})}.
-
-@findex RTX_COSTS
-@findex COSTS_N_INSNS
-@item RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
-Like @code{CONST_COSTS} but applies to nonconstant RTL expressions.
-This can be used, for example, to indicate how costly a multiply
-instruction is. In writing this macro, you can use the construct
-@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
-instructions. @var{outer_code} is the code of the expression in which
-@var{x} is contained.
-
-This macro is optional; do not define it if the default cost assumptions
-are adequate for the target machine.
-
-@findex DEFAULT_RTX_COSTS
-@item DEFAULT_RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
-This macro, if defined, is called for any case not handled by the
-@code{RTX_COSTS} or @code{CONST_COSTS} macros. This eliminates the need
-to put case labels into the macro, but the code, or any functions it
-calls, must assume that the RTL in @var{x} could be of any type that has
-not already been handled. The arguments are the same as for
-@code{RTX_COSTS}, and the macro should execute a return statement giving
-the cost of any RTL expressions that it can handle. The default cost
-calculation is used for any RTL for which this macro does not return a
-value.
-
-This macro is optional; do not define it if the default cost assumptions
-are adequate for the target machine.
-
-@findex ADDRESS_COST
-@item ADDRESS_COST (@var{address})
-An expression giving the cost of an addressing mode that contains
-@var{address}. If not defined, the cost is computed from
-the @var{address} expression and the @code{CONST_COSTS} values.
-
-For most CISC machines, the default cost is a good approximation of the
-true cost of the addressing mode. However, on RISC machines, all
-instructions normally have the same length and execution time. Hence
-all addresses will have equal costs.
-
-In cases where more than one form of an address is known, the form with
-the lowest cost will be used. If multiple forms have the same, lowest,
-cost, the one that is the most complex will be used.
-
-For example, suppose an address that is equal to the sum of a register
-and a constant is used twice in the same basic block. When this macro
-is not defined, the address will be computed in a register and memory
-references will be indirect through that register. On machines where
-the cost of the addressing mode containing the sum is no higher than
-that of a simple indirect reference, this will produce an additional
-instruction and possibly require an additional register. Proper
-specification of this macro eliminates this overhead for such machines.
-
-Similar use of this macro is made in strength reduction of loops.
-
-@var{address} need not be valid as an address. In such a case, the cost
-is not relevant and can be any value; invalid addresses need not be
-assigned a different cost.
-
-On machines where an address involving more than one register is as
-cheap as an address computation involving only one register, defining
-@code{ADDRESS_COST} to reflect this can cause two registers to be live
-over a region of code where only one would have been if
-@code{ADDRESS_COST} were not defined in that manner. This effect should
-be considered in the definition of this macro. Equivalent costs should
-probably only be given to addresses with different numbers of registers
-on machines with lots of registers.
-
-This macro will normally either not be defined or be defined as a
-constant.
-
-@findex REGISTER_MOVE_COST
-@item REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
+@defmac REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
A C expression for the cost of moving data of mode @var{mode} from a
register in class @var{from} to one in class @var{to}. The classes are
expressed using the enumeration values such as @code{GENERAL_REGS}. A
constraints of the insn are met. Setting a cost of other than 2 will
allow reload to verify that the constraints are met. You should do this
if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
+@end defmac
-@findex MEMORY_MOVE_COST
-@item MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
+@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
A C expression for the cost of moving data of mode @var{mode} between a
register of class @var{class} and memory; @var{in} is zero if the value
is to be written to memory, nonzero if it is to be read in. This cost
4 is not correct for your machine, define this macro to add some other
value to the result of that function. The arguments to that function
are the same as to this macro.
+@end defmac
-@findex BRANCH_COST
-@item BRANCH_COST
+@defmac BRANCH_COST
A C expression for the cost of a branch instruction. A value of 1 is
the default; other values are interpreted relative to that.
-@end table
+@end defmac
Here are additional macros which do not specify precise relative costs,
but only that certain actions are more expensive than GCC would
ordinarily expect.
-@table @code
-@findex SLOW_BYTE_ACCESS
-@item SLOW_BYTE_ACCESS
+@defmac SLOW_BYTE_ACCESS
Define this macro as a C expression which is nonzero if accessing less
than a word of memory (i.e.@: a @code{char} or a @code{short}) is no
faster than accessing a word of memory, i.e., if such access
faster than word accesses, using word accesses is preferable since it
may eliminate subsequent memory access if subsequent accesses occur to
other fields in the same word of the structure, but to different bytes.
+@end defmac
-@findex SLOW_UNALIGNED_ACCESS
-@item SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment})
+@defmac SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment})
Define this macro to be the value 1 if memory accesses described by the
@var{mode} and @var{alignment} parameters have a cost many times greater
than aligned accesses, for example if they are emulated in a trap
If the value of this macro is always zero, it need not be defined. If
this macro is defined, it should produce a nonzero value when
@code{STRICT_ALIGNMENT} is nonzero.
+@end defmac
-@findex DONT_REDUCE_ADDR
-@item DONT_REDUCE_ADDR
-Define this macro to inhibit strength reduction of memory addresses.
-(On some machines, such strength reduction seems to do harm rather
-than good.)
-
-@findex MOVE_RATIO
-@item MOVE_RATIO
+@defmac MOVE_RATIO
The threshold of number of scalar memory-to-memory move insns, @emph{below}
which a sequence of insns should be generated instead of a
string move insn or a library call. Increasing the value will always
the number of such sequences.
If you don't define this, a reasonable default is used.
+@end defmac
-@findex MOVE_BY_PIECES_P
-@item MOVE_BY_PIECES_P (@var{size}, @var{alignment})
+@defmac MOVE_BY_PIECES_P (@var{size}, @var{alignment})
A C expression used to determine whether @code{move_by_pieces} will be used to
copy a chunk of memory, or whether some other block move mechanism
will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
than @code{MOVE_RATIO}.
+@end defmac
-@findex MOVE_MAX_PIECES
-@item MOVE_MAX_PIECES
+@defmac MOVE_MAX_PIECES
A C expression used by @code{move_by_pieces} to determine the largest unit
a load or store used to copy memory is. Defaults to @code{MOVE_MAX}.
+@end defmac
-@findex CLEAR_RATIO
-@item CLEAR_RATIO
+@defmac CLEAR_RATIO
The threshold of number of scalar move insns, @emph{below} which a sequence
of insns should be generated to clear memory instead of a string clear insn
or a library call. Increasing the value will always make code faster, but
eventually incurs high cost in increased code size.
If you don't define this, a reasonable default is used.
+@end defmac
-@findex CLEAR_BY_PIECES_P
-@item CLEAR_BY_PIECES_P (@var{size}, @var{alignment})
+@defmac CLEAR_BY_PIECES_P (@var{size}, @var{alignment})
A C expression used to determine whether @code{clear_by_pieces} will be used
to clear a chunk of memory, or whether some other block clear mechanism
will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
than @code{CLEAR_RATIO}.
+@end defmac
+
+@defmac STORE_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{store_by_pieces} will be
+used to set a chunk of memory to a constant value, or whether some other
+mechanism will be used. Used by @code{__builtin_memset} when storing
+values other than constant zero and by @code{__builtin_strcpy} when
+when called with a constant source string.
+Defaults to @code{MOVE_BY_PIECES_P}.
+@end defmac
-@findex USE_LOAD_POST_INCREMENT
-@item USE_LOAD_POST_INCREMENT (@var{mode})
+@defmac USE_LOAD_POST_INCREMENT (@var{mode})
A C expression used to determine whether a load postincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_INCREMENT}.
+@end defmac
-@findex USE_LOAD_POST_DECREMENT
-@item USE_LOAD_POST_DECREMENT (@var{mode})
+@defmac USE_LOAD_POST_DECREMENT (@var{mode})
A C expression used to determine whether a load postdecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_DECREMENT}.
+@end defmac
-@findex USE_LOAD_PRE_INCREMENT
-@item USE_LOAD_PRE_INCREMENT (@var{mode})
+@defmac USE_LOAD_PRE_INCREMENT (@var{mode})
A C expression used to determine whether a load preincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_INCREMENT}.
+@end defmac
-@findex USE_LOAD_PRE_DECREMENT
-@item USE_LOAD_PRE_DECREMENT (@var{mode})
+@defmac USE_LOAD_PRE_DECREMENT (@var{mode})
A C expression used to determine whether a load predecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_DECREMENT}.
+@end defmac
-@findex USE_STORE_POST_INCREMENT
-@item USE_STORE_POST_INCREMENT (@var{mode})
+@defmac USE_STORE_POST_INCREMENT (@var{mode})
A C expression used to determine whether a store postincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_INCREMENT}.
+@end defmac
-@findex USE_STORE_POST_DECREMENT
-@item USE_STORE_POST_DECREMENT (@var{mode})
+@defmac USE_STORE_POST_DECREMENT (@var{mode})
A C expression used to determine whether a store postdecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_DECREMENT}.
+@end defmac
-@findex USE_STORE_PRE_INCREMENT
-@item USE_STORE_PRE_INCREMENT (@var{mode})
+@defmac USE_STORE_PRE_INCREMENT (@var{mode})
This macro is used to determine whether a store preincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_INCREMENT}.
+@end defmac
-@findex USE_STORE_PRE_DECREMENT
-@item USE_STORE_PRE_DECREMENT (@var{mode})
+@defmac USE_STORE_PRE_DECREMENT (@var{mode})
This macro is used to determine whether a store predecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_DECREMENT}.
+@end defmac
-@findex NO_FUNCTION_CSE
-@item NO_FUNCTION_CSE
+@defmac NO_FUNCTION_CSE
Define this macro if it is as good or better to call a constant
function address than to call an address kept in a register.
+@end defmac
-@findex NO_RECURSIVE_FUNCTION_CSE
-@item NO_RECURSIVE_FUNCTION_CSE
+@defmac NO_RECURSIVE_FUNCTION_CSE
Define this macro if it is as good or better for a function to call
itself with an explicit address than to call an address kept in a
register.
-@end table
+@end defmac
+
+@defmac RANGE_TEST_NON_SHORT_CIRCUIT
+Define this macro if a non-short-circuit operation produced by
+@samp{fold_range_test ()} is optimal. This macro defaults to true if
+@code{BRANCH_COST} is greater than or equal to the value 2.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_RTX_COSTS (rtx @var{x}, int @var{code}, int @var{outer_code}, int *@var{total})
+This target hook describes the relative costs of RTL expressions.
+
+The cost may depend on the precise form of the expression, which is
+available for examination in @var{x}, and the rtx code of the expression
+in which it is contained, found in @var{outer_code}. @var{code} is the
+expression code---redundant, since it can be obtained with
+@code{GET_CODE (@var{x})}.
+
+In implementing this hook, you can use the construct
+@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
+instructions.
+
+On entry to the hook, @code{*@var{total}} contains a default estimate
+for the cost of the expression. The hook should modify this value as
+necessary.
+
+The hook returns true when all subexpressions of @var{x} have been
+processed, and false when @code{rtx_cost} should recurse.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_ADDRESS_COST (rtx @var{address})
+This hook computes the cost of an addressing mode that contains
+@var{address}. If not defined, the cost is computed from
+the @var{address} expression and the @code{TARGET_RTX_COST} hook.
+
+For most CISC machines, the default cost is a good approximation of the
+true cost of the addressing mode. However, on RISC machines, all
+instructions normally have the same length and execution time. Hence
+all addresses will have equal costs.
+
+In cases where more than one form of an address is known, the form with
+the lowest cost will be used. If multiple forms have the same, lowest,
+cost, the one that is the most complex will be used.
+
+For example, suppose an address that is equal to the sum of a register
+and a constant is used twice in the same basic block. When this macro
+is not defined, the address will be computed in a register and memory
+references will be indirect through that register. On machines where
+the cost of the addressing mode containing the sum is no higher than
+that of a simple indirect reference, this will produce an additional
+instruction and possibly require an additional register. Proper
+specification of this macro eliminates this overhead for such machines.
+
+This hook is never called with an invalid address.
+
+On machines where an address involving more than one register is as
+cheap as an address computation involving only one register, defining
+@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to
+be live over a region of code where only one would have been if
+@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect
+should be considered in the definition of this macro. Equivalent costs
+should probably only be given to addresses with different numbers of
+registers on machines with lots of registers.
+@end deftypefn
@node Scheduling
@section Adjusting the Instruction Scheduler
@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
This hook is executed by the scheduler after it has scheduled an insn
from the ready list. It should return the number of insns which can
-still be issued in the current cycle. Normally this is
-@samp{@w{@var{more} - 1}}. You should define this hook if some insns
-take more machine resources than others, so that fewer insns can follow
-them in the same cycle. @var{file} is either a null pointer, or a stdio
-stream to write any debug output to. @var{verbose} is the verbose level
-provided by @option{-fsched-verbose-@var{n}}. @var{insn} is the
-instruction that was scheduled.
+still be issued in the current cycle. The default is
+@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and
+@code{USE}, which normally are not counted against the issue rate.
+You should define this hook if some insns take more machine resources
+than others, so that fewer insns can follow them in the same cycle.
+@var{file} is either a null pointer, or a stdio stream to write any
+debug output to. @var{verbose} is the verbose level provided by
+@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that
+was scheduled.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST (rtx @var{insn}, rtx @var{link}, rtx @var{dep_insn}, int @var{cost})
cycle. These other insns can then be taken into account properly.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK (rtx @var{head}, rtx @var{tail})
+This hook is called after evaluation forward dependencies of insns in
+chain given by two parameter values (@var{head} and @var{tail}
+correspondingly) but before insns scheduling of the insn chain. For
+example, it can be used for better insn classification if it requires
+analysis of dependencies. This hook can use backward and forward
+dependencies of the insn scheduler because they are already
+calculated.
+@end deftypefn
+
@deftypefn {Target Hook} void TARGET_SCHED_INIT (FILE *@var{file}, int @var{verbose}, int @var{max_ready})
This hook is executed by the scheduler at the beginning of each block of
instructions that are to be scheduled. @var{file} is either a null
The default is no multipass scheduling.
@end deftypefn
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD (rtx)
+
+This hook controls what insns from the ready insn queue will be
+considered for the multipass insn scheduling. If the hook returns
+zero for insn passed as the parameter, the insn will be not chosen to
+be issued.
+
+The default is that any ready insns can be chosen to be issued.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_NEW_CYCLE (FILE *, int, rtx, int, int, int *)
+
+This hook is called by the insn scheduler before issuing insn passed
+as the third parameter on given cycle. If the hook returns nonzero,
+the insn is not issued on given processors cycle. Instead of that,
+the processor cycle is advanced. If the value passed through the last
+parameter is zero, the insn ready queue is not sorted on the new cycle
+start as usually. The first parameter passes file for debugging
+output. The second one passes the scheduler verbose level of the
+debugging output. The forth and the fifth parameter values are
+correspondingly processor cycle on which the previous insn has been
+issued and the current processor cycle.
+@end deftypefn
+
@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_BUBBLES (void)
The @acronym{DFA}-based scheduler could take the insertion of nop
operations for better insn scheduling into account. It can be done
Macros in the following table are generated by the program
@file{genattr} and can be useful for writing the hooks.
-@table @code
-@findex TRADITIONAL_PIPELINE_INTERFACE
-@item TRADITIONAL_PIPELINE_INTERFACE
+@defmac TRADITIONAL_PIPELINE_INTERFACE
The macro definition is generated if there is a traditional pipeline
description in @file{.md} file. You should also remember that to
simplify the insn scheduler sources an empty traditional pipeline
description interface is generated even if there is no a traditional
pipeline description in the @file{.md} file. The macro can be used to
distinguish the two types of the traditional interface.
+@end defmac
-@findex DFA_PIPELINE_INTERFACE
-@item DFA_PIPELINE_INTERFACE
+@defmac DFA_PIPELINE_INTERFACE
The macro definition is generated if there is an automaton pipeline
description in @file{.md} file. You should also remember that to
simplify the insn scheduler sources an empty automaton pipeline
description interface is generated even if there is no an automaton
pipeline description in the @file{.md} file. The macro can be used to
distinguish the two types of the automaton interface.
+@end defmac
-@findex MAX_DFA_ISSUE_RATE
-@item MAX_DFA_ISSUE_RATE
+@defmac MAX_DFA_ISSUE_RATE
The macro definition is generated in the automaton based pipeline
description interface. Its value is calculated from the automaton
based pipeline description and is equal to maximal number of all insns
described in constructions @samp{define_insn_reservation} which can be
issued on the same processor cycle.
-
-@end table
+@end defmac
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
macros control what commands to output to tell the assembler this. You
can also define additional sections.
-@table @code
-@findex TEXT_SECTION_ASM_OP
-@item TEXT_SECTION_ASM_OP
+@defmac TEXT_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
assembler operation that should precede instructions and read-only data.
Normally @code{"\t.text"} is right.
+@end defmac
-@findex TEXT_SECTION
-@item TEXT_SECTION
+@defmac TEXT_SECTION
A C statement that switches to the default section containing instructions.
Normally this is not needed, as simply defining @code{TEXT_SECTION_ASM_OP}
is enough. The MIPS port uses this to sort all functions after all data
declarations.
+@end defmac
-@findex HOT_TEXT_SECTION_NAME
-@item HOT_TEXT_SECTION_NAME
+@defmac HOT_TEXT_SECTION_NAME
If defined, a C string constant for the name of the section containing most
frequently executed functions of the program. If not defined, GCC will provide
a default definition if the target supports named sections.
+@end defmac
-@findex UNLIKELY_EXECUTED_TEXT_SECTION_NAME
-@item UNLIKELY_EXECUTED_TEXT_SECTION_NAME
+@defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME
If defined, a C string constant for the name of the section containing unlikely
executed functions in the program.
+@end defmac
-@findex DATA_SECTION_ASM_OP
-@item DATA_SECTION_ASM_OP
+@defmac DATA_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
assembler operation to identify the following data as writable initialized
data. Normally @code{"\t.data"} is right.
+@end defmac
-@findex READONLY_DATA_SECTION_ASM_OP
-@item READONLY_DATA_SECTION_ASM_OP
+@defmac READONLY_DATA_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
assembler operation to identify the following data as read-only initialized
data.
+@end defmac
-@findex READONLY_DATA_SECTION
-@item READONLY_DATA_SECTION
+@defmac READONLY_DATA_SECTION
A macro naming a function to call to switch to the proper section for
read-only data. The default is to use @code{READONLY_DATA_SECTION_ASM_OP}
if defined, else fall back to @code{text_section}.
The most common definition will be @code{data_section}, if the target
does not have a special read-only data section, and does not put data
in the text section.
+@end defmac
-@findex SHARED_SECTION_ASM_OP
-@item SHARED_SECTION_ASM_OP
+@defmac SHARED_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
shared data. If not defined, @code{DATA_SECTION_ASM_OP} will be used.
+@end defmac
-@findex BSS_SECTION_ASM_OP
-@item BSS_SECTION_ASM_OP
+@defmac BSS_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
uninitialized global data. If not defined, and neither
uninitialized global data will be output in the data section if
@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be
used.
+@end defmac
-@findex SHARED_BSS_SECTION_ASM_OP
-@item SHARED_BSS_SECTION_ASM_OP
+@defmac SHARED_BSS_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
uninitialized global shared data. If not defined, and
@code{BSS_SECTION_ASM_OP} is, the latter will be used.
+@end defmac
-@findex INIT_SECTION_ASM_OP
-@item INIT_SECTION_ASM_OP
+@defmac INIT_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
initialization code. If not defined, GCC will assume such a section does
not exist.
+@end defmac
-@findex FINI_SECTION_ASM_OP
-@item FINI_SECTION_ASM_OP
+@defmac FINI_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
finalization code. If not defined, GCC will assume such a section does
not exist.
+@end defmac
-@findex CRT_CALL_STATIC_FUNCTION
-@item CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
+@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
If defined, an ASM statement that switches to a different section
via @var{section_op}, calls @var{function}, and switches back to
the text section. This is used in @file{crtstuff.c} if
ports need hand-crafted assembly code to avoid dependencies on
registers initialized in the function prologue or to ensure that
constant pools don't end up too far way in the text section.
+@end defmac
-@findex FORCE_CODE_SECTION_ALIGN
-@item FORCE_CODE_SECTION_ALIGN
+@defmac FORCE_CODE_SECTION_ALIGN
If defined, an ASM statement that aligns a code section to some
arbitrary boundary. This is used to force all fragments of the
@code{.init} and @code{.fini} sections to have to same alignment
and thus prevent the linker from having to add any padding.
+@end defmac
-@findex EXTRA_SECTIONS
@findex in_text
@findex in_data
-@item EXTRA_SECTIONS
+@defmac EXTRA_SECTIONS
A list of names for sections other than the standard two, which are
@code{in_text} and @code{in_data}. You need not define this macro
on a system with no other sections (that GCC needs to use).
+@end defmac
-@findex EXTRA_SECTION_FUNCTIONS
@findex text_section
@findex data_section
-@item EXTRA_SECTION_FUNCTIONS
+@defmac EXTRA_SECTION_FUNCTIONS
One or more functions to be defined in @file{varasm.c}. These
functions should do jobs analogous to those of @code{text_section} and
@code{data_section}, for your additional sections. Do not define this
macro if you do not define @code{EXTRA_SECTIONS}.
+@end defmac
-@findex JUMP_TABLES_IN_TEXT_SECTION
-@item JUMP_TABLES_IN_TEXT_SECTION
+@defmac JUMP_TABLES_IN_TEXT_SECTION
Define this macro to be an expression with a nonzero value if jump
tables (for @code{tablejump} insns) should be output in the text
section, along with the assembler instructions. Otherwise, the
readonly data section is used.
This macro is irrelevant if there is no separate readonly data section.
-@end table
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align})
Switches to the appropriate section for output of @var{exp}. You can
else in @code{readonly_data_section}.
@end deftypefn
-@deftypefn {Target Hook} void TARGET_ENCODE_SECTION_INFO (tree @var{decl}, int @var{new_decl_p})
+@deftypefn {Target Hook} void TARGET_ENCODE_SECTION_INFO (tree @var{decl}, rtx @var{rtl}, int @var{new_decl_p})
Define this hook if references to a symbol or a constant must be
treated differently depending on something about the variable or
function named by the symbol (such as what section it is in).
-The hook is executed under two circumstances. One is immediately after
-the rtl for @var{decl} that represents a variable or a function has been
-created and stored in @code{DECL_RTL(@var{decl})}. The value of the rtl
-will be a @code{mem} whose address is a @code{symbol_ref}. The other is
-immediately after the rtl for @var{decl} that represents a constant has
-been created and stored in @code{TREE_CST_RTL (@var{decl})}. The macro
-is called once for each distinct constant in a source file.
+The hook is executed immediately after rtl has been created for
+@var{decl}, which may be a variable or function declaration or
+an entry in the constant pool. In either case, @var{rtl} is the
+rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}
+in this hook; that field may not have been initialized yet.
+
+In the case of a constant, it is safe to assume that the rtl is
+a @code{mem} whose address is a @code{symbol_ref}. Most decls
+will also have this form, but that is not guaranteed. Global
+register variables, for instance, will have a @code{reg} for their
+rtl. (Normally the right thing to do with such unusual rtl is
+leave it alone.)
The @var{new_decl_p} argument will be true if this is the first time
-that @code{ENCODE_SECTION_INFO} has been invoked on this decl. It will
+that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will
be false for subsequent invocations, which will happen for duplicate
declarations. Whether or not anything must be done for the duplicate
declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.
+@var{new_decl_p} is always true when the hook is called for a constant.
@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}
-The usual thing for this hook to do is to record a flag in the
-@code{symbol_ref} (such as @code{SYMBOL_REF_FLAG}) or to store a
-modified name string in the @code{symbol_ref} (if one bit is not
-enough information).
+The usual thing for this hook to do is to record flags in the
+@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.
+Historically, the name string was modified if it was necessary to
+encode more than one bit of information, but this practice is now
+discouraged; use @code{SYMBOL_REF_FLAGS}.
+
+The default definition of this hook, @code{default_encode_section_info}
+in @file{varasm.c}, sets a number of commonly-useful bits in
+@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need
+before overriding it.
@end deftypefn
@deftypefn {Target Hook} const char *TARGET_STRIP_NAME_ENCODING (const char *name)
@c i rearranged the order of the macros above to try to force one of
@c them to the next line, to eliminate an overfull hbox. --mew 10feb93
-@table @code
-@findex PIC_OFFSET_TABLE_REGNUM
-@item PIC_OFFSET_TABLE_REGNUM
+@defmac PIC_OFFSET_TABLE_REGNUM
The register number of the register used to address a table of static
data addresses in memory. In some cases this register is defined by a
processor's ``application binary interface'' (ABI)@. When this macro
is up to the machine-dependent files to allocate such a register (if
necessary). Note that this register must be fixed when in use (e.g.@:
when @code{flag_pic} is true).
+@end defmac
-@findex PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-@item PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+@defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
Define this macro if the register defined by
@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls. Do not define
this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
+@end defmac
-@findex FINALIZE_PIC
-@item FINALIZE_PIC
+@defmac FINALIZE_PIC
By generating position-independent code, when two different programs (A
and B) share a common library (libC.a), the text of the library can be
shared whether or not the library is linked at the same address for both
inline function, it would lead to multiple PIC prologues being
included in functions which used inline functions and were compiled to
assembly language.)
+@end defmac
-@findex LEGITIMATE_PIC_OPERAND_P
-@item LEGITIMATE_PIC_OPERAND_P (@var{x})
+@defmac LEGITIMATE_PIC_OPERAND_P (@var{x})
A C expression that is nonzero if @var{x} is a legitimate immediate
operand on the target machine when generating position independent code.
You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not
check it either. You need not define this macro if all constants
(including @code{SYMBOL_REF}) can be immediate operands when generating
position independent code.
-@end table
+@end defmac
@node Assembler Format
@section Defining the Output Assembler Language
@cindex output of assembler code
@c prevent bad page break with this line
-This describes the overall framework of an assembler file.
-
-@table @code
-@findex ASM_FILE_START
-@item ASM_FILE_START (@var{stream})
-A C expression which outputs to the stdio stream @var{stream}
-some appropriate text to go at the start of an assembler file.
-
-Normally this macro is defined to output a line containing
-@samp{#NO_APP}, which is a comment that has no effect on most
-assemblers but tells the GNU assembler that it can save time by not
-checking for certain assembler constructs.
+This describes the overall framework of an assembly file.
+
+@deftypefn {Target Hook} void TARGET_ASM_FILE_START ()
+@findex default_file_start
+Output to @code{asm_out_file} any text which the assembler expects to
+find at the beginning of a file. The default behavior is controlled
+by two flags, documented below. Unless your target's assembler is
+quite unusual, if you override the default, you should call
+@code{default_file_start} at some point in your target hook. This
+lets other target files rely on these variables.
+@end deftypefn
-On systems that use SDB, it is necessary to output certain commands;
-see @file{attasm.h}.
+@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_APP_OFF
+If this flag is true, the text of the macro @code{ASM_APP_OFF} will be
+printed as the very first line in the assembly file, unless
+@option{-fverbose-asm} is in effect. (If that macro has been defined
+to the empty string, this variable has no effect.) With the normal
+definition of @code{ASM_APP_OFF}, the effect is to notify the GNU
+assembler that it need not bother stripping comments or extra
+whitespace from its input. This allows it to work a bit faster.
+
+The default is false. You should not set it to true unless you have
+verified that your port does not generate any extra whitespace or
+comments that will cause GAS to issue errors in NO_APP mode.
+@end deftypevr
-@findex ASM_FILE_END
-@item ASM_FILE_END (@var{stream})
-A C expression which outputs to the stdio stream @var{stream}
-some appropriate text to go at the end of an assembler file.
+@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_FILE_DIRECTIVE
+If this flag is true, @code{output_file_directive} will be called
+for the primary source file, immediately after printing
+@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect
+this to be done. The default is false.
+@end deftypevr
-If this macro is not defined, the default is to output nothing
-special at the end of the file. Most systems don't require any
-definition.
+@deftypefn {Target Hook} void TARGET_ASM_FILE_END ()
+Output to @code{asm_out_file} any text which the assembler expects
+to find at the end of a file. The default is to output nothing.
+@end deftypefn
-On systems that use SDB, it is necessary to output certain commands;
-see @file{attasm.h}.
+@deftypefun void file_end_indicate_exec_stack ()
+Some systems use a common convention, the @samp{.note.GNU-stack}
+special section, to indicate whether or not an object file relies on
+the stack being executable. If your system uses this convention, you
+should define @code{TARGET_ASM_FILE_END} to this function. If you
+need to do other things in that hook, have your hook function call
+this function.
+@end deftypefun
-@findex ASM_COMMENT_START
-@item ASM_COMMENT_START
+@defmac ASM_COMMENT_START
A C string constant describing how to begin a comment in the target
assembler language. The compiler assumes that the comment will end at
the end of the line.
+@end defmac
-@findex ASM_APP_ON
-@item ASM_APP_ON
+@defmac ASM_APP_ON
A C string constant for text to be output before each @code{asm}
statement or group of consecutive ones. Normally this is
@code{"#APP"}, which is a comment that has no effect on most
assemblers but tells the GNU assembler that it must check the lines
that follow for all valid assembler constructs.
+@end defmac
-@findex ASM_APP_OFF
-@item ASM_APP_OFF
+@defmac ASM_APP_OFF
A C string constant for text to be output after each @code{asm}
statement or group of consecutive ones. Normally this is
@code{"#NO_APP"}, which tells the GNU assembler to resume making the
time-saving assumptions that are valid for ordinary compiler output.
+@end defmac
-@findex ASM_OUTPUT_SOURCE_FILENAME
-@item ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
A C statement to output COFF information or DWARF debugging information
which indicates that filename @var{name} is the current source file to
the stdio stream @var{stream}.
This macro need not be defined if the standard form of output
for the file format in use is appropriate.
+@end defmac
-@findex OUTPUT_QUOTED_STRING
-@item OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
+@defmac OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
A C statement to output the string @var{string} to the stdio stream
@var{stream}. If you do not call the function @code{output_quoted_string}
in your config files, GCC will only call it to output filenames to
the assembler source. So you can use it to canonicalize the format
of the filename using this macro.
+@end defmac
-@findex ASM_OUTPUT_SOURCE_LINE
-@item ASM_OUTPUT_SOURCE_LINE (@var{stream}, @var{line})
+@defmac ASM_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}, @var{counter})
A C statement to output DBX or SDB debugging information before code
for line number @var{line} of the current source file to the
-stdio stream @var{stream}.
+stdio stream @var{stream}. @var{counter} is the number of time the
+macro was invoked, including the current invocation; it is intended
+to generate unique labels in the assembly output.
This macro need not be defined if the standard form of debugging
information for the debugger in use is appropriate.
+@end defmac
-@findex ASM_OUTPUT_IDENT
-@item ASM_OUTPUT_IDENT (@var{stream}, @var{string})
+@defmac ASM_OUTPUT_IDENT (@var{stream}, @var{string})
A C statement to output something to the assembler file to handle a
@samp{#ident} directive containing the text @var{string}. If this
macro is not defined, nothing is output for a @samp{#ident} directive.
-
-@findex OBJC_PROLOGUE
-@item OBJC_PROLOGUE
-A C statement to output any assembler statements which are required to
-precede any Objective-C object definitions or message sending. The
-statement is executed only when compiling an Objective-C program.
-@end table
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags}, unsigned int @var{align})
Output assembly directives to switch to section @var{name}. The section
when the relevant string is @code{NULL}.
@end deftypefn
-@table @code
-@findex OUTPUT_ADDR_CONST_EXTRA
-@item OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail})
+@defmac OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail})
A C statement to recognize @var{rtx} patterns that
@code{output_addr_const} can't deal with, and output assembly code to
@var{stream} corresponding to the pattern @var{x}. This may be used to
@code{goto fail}, so that a standard error message is printed. If it
prints an error message itself, by calling, for example,
@code{output_operand_lossage}, it may just complete normally.
+@end defmac
-@findex ASM_OUTPUT_ASCII
-@item ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
+@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
A C statement to output to the stdio stream @var{stream} an assembler
instruction to assemble a string constant containing the @var{len}
bytes at @var{ptr}. @var{ptr} will be a C expression of type
If the assembler has a @code{.ascii} pseudo-op as found in the
Berkeley Unix assembler, do not define the macro
@code{ASM_OUTPUT_ASCII}.
+@end defmac
-@findex ASM_OUTPUT_FDESC
-@item ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
+@defmac ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
A C statement to output word @var{n} of a function descriptor for
@var{decl}. This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS}
is defined, and is otherwise unused.
+@end defmac
-@findex CONSTANT_POOL_BEFORE_FUNCTION
-@item CONSTANT_POOL_BEFORE_FUNCTION
+@defmac CONSTANT_POOL_BEFORE_FUNCTION
You may define this macro as a C expression. You should define the
expression to have a nonzero value if GCC should output the constant
pool for a function before the code for the function, or a zero value if
GCC should output the constant pool after the function. If you do
not define this macro, the usual case, GCC will output the constant
pool before the function.
+@end defmac
-@findex ASM_OUTPUT_POOL_PROLOGUE
-@item ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
+@defmac ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
A C statement to output assembler commands to define the start of the
constant pool for a function. @var{funname} is a string giving
the name of the function. Should the return type of the function
If no constant-pool prefix is required, the usual case, this macro need
not be defined.
+@end defmac
-@findex ASM_OUTPUT_SPECIAL_POOL_ENTRY
-@item ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
+@defmac ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
A C statement (with or without semicolon) to output a constant in the
constant pool, if it needs special treatment. (This macro need not do
anything for RTL expressions that can be output normally.)
Here is how to do this:
@example
-ASM_OUTPUT_INTERNAL_LABEL (@var{file}, "LC", @var{labelno});
+@code{(*targetm.asm_out.internal_label)} (@var{file}, "LC", @var{labelno});
@end example
When you output a pool entry specially, you should end with a
entry from being output a second time in the usual manner.
You need not define this macro if it would do nothing.
+@end defmac
-@findex CONSTANT_AFTER_FUNCTION_P
-@item CONSTANT_AFTER_FUNCTION_P (@var{exp})
-Define this macro as a C expression which is nonzero if the constant
-@var{exp}, of type @code{tree}, should be output after the code for a
-function. The compiler will normally output all constants before the
-function; you need not define this macro if this is OK@.
-
-@findex ASM_OUTPUT_POOL_EPILOGUE
-@item ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
+@defmac ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
A C statement to output assembler commands to at the end of the constant
pool for a function. @var{funname} is a string giving the name of the
function. Should the return type of the function be required, you can
If no constant-pool epilogue is required, the usual case, you need not
define this macro.
+@end defmac
-@findex IS_ASM_LOGICAL_LINE_SEPARATOR
-@item IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C})
+@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C})
Define this macro as a C expression which is nonzero if @var{C} is
used as a logical line separator by the assembler.
If you do not define this macro, the default is that only
the character @samp{;} is treated as a logical line separator.
-@end table
+@end defmac
@deftypevr {Target Hook} {const char *} TARGET_ASM_OPEN_PAREN
@deftypevrx {Target Hook} {const char *} TARGET_ASM_CLOSE_PAREN
These macros are provided by @file{real.h} for writing the definitions
of @code{ASM_OUTPUT_DOUBLE} and the like:
-@table @code
-@item REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
-@itemx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
-@itemx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
-@findex REAL_VALUE_TO_TARGET_SINGLE
-@findex REAL_VALUE_TO_TARGET_DOUBLE
-@findex REAL_VALUE_TO_TARGET_LONG_DOUBLE
+@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the target's
floating point representation, and store its bit pattern in the variable
@var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE}, this variable should
The array element values are designed so that you can print them out
using @code{fprintf} in the order they should appear in the target
machine's memory.
-
-@item REAL_VALUE_TO_DECIMAL (@var{x}, @var{string}, @var{digits})
-@findex REAL_VALUE_TO_DECIMAL
-This macro converts @var{x}, of type @code{REAL_VALUE_TYPE}, to a
-decimal number and stores it as a string into @var{string}.
-You must pass, as @var{string}, the address of a long enough block
-of space to hold the result.
-
-The argument @var{digits} is the number of decimal digits to print,
-or @minus{}1 to indicate ``enough'', i.e. @code{DECIMAL_DIG} for
-for the target.
-@end table
+@end defmac
@node Uninitialized Data
@subsection Output of Uninitialized Variables
Each of the macros in this section is used to do the whole job of
outputting a single uninitialized variable.
-@table @code
-@findex ASM_OUTPUT_COMMON
-@item ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a common-label named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
This macro controls how the assembler definitions of uninitialized
common global variables are output.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_COMMON
-@item ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in
handling the required alignment of the variable. The alignment is specified
as the number of bits.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_DECL_COMMON
-@item ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the
variable to be output, if there is one, or @code{NULL_TREE} if there
is no corresponding variable. If you define this macro, GCC will use it
in place of both @code{ASM_OUTPUT_COMMON} and
@code{ASM_OUTPUT_ALIGNED_COMMON}. Define this macro when you need to see
the variable's decl in order to chose what to output.
+@end defmac
-@findex ASM_OUTPUT_SHARED_COMMON
-@item ASM_OUTPUT_SHARED_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_SHARED_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
If defined, it is similar to @code{ASM_OUTPUT_COMMON}, except that it
is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_COMMON}
will be used.
+@end defmac
-@findex ASM_OUTPUT_BSS
-@item ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of uninitialized global @var{decl} named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
@code{ASM_OUTPUT_ALIGNED_BSS} are not defined then @code{ASM_OUTPUT_COMMON}
or @code{ASM_OUTPUT_ALIGNED_COMMON} or
@code{ASM_OUTPUT_ALIGNED_DECL_COMMON} is used.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_BSS
-@item ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_BSS} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_BSS}, and gives you more flexibility in
Try to use function @code{asm_output_aligned_bss} defined in file
@file{varasm.c} when defining this macro.
+@end defmac
-@findex ASM_OUTPUT_SHARED_BSS
-@item ASM_OUTPUT_SHARED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_SHARED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
If defined, it is similar to @code{ASM_OUTPUT_BSS}, except that it
is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_BSS}
will be used.
+@end defmac
-@findex ASM_OUTPUT_LOCAL
-@item ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a local-common-label named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
This macro controls how the assembler definitions of uninitialized
static variables are output.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_LOCAL
-@item ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in
handling the required alignment of the variable. The alignment is specified
as the number of bits.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_DECL_LOCAL
-@item ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_ALIGNED_DECL} except that @var{decl} of the
variable to be output, if there is one, or @code{NULL_TREE} if there
is no corresponding variable. If you define this macro, GCC will use it
in place of both @code{ASM_OUTPUT_DECL} and
@code{ASM_OUTPUT_ALIGNED_DECL}. Define this macro when you need to see
the variable's decl in order to chose what to output.
+@end defmac
-@findex ASM_OUTPUT_SHARED_LOCAL
-@item ASM_OUTPUT_SHARED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_SHARED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
If defined, it is similar to @code{ASM_OUTPUT_LOCAL}, except that it
is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_LOCAL}
will be used.
-@end table
+@end defmac
@node Label Output
@subsection Output and Generation of Labels
@c prevent bad page break with this line
This is about outputting labels.
-@table @code
-@findex ASM_OUTPUT_LABEL
@findex assemble_name
-@item ASM_OUTPUT_LABEL (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a label named @var{name}.
Use the expression @code{assemble_name (@var{stream}, @var{name})} to
output the name itself; before and after that, output the additional
assembler syntax for defining the name, and a newline. A default
definition of this macro is provided which is correct for most systems.
+@end defmac
-@findex SIZE_ASM_OP
-@item SIZE_ASM_OP
+@defmac SIZE_ASM_OP
A C string containing the appropriate assembler directive to specify the
size of a symbol, without any arguments. On systems that use ELF, the
default (in @file{config/elfos.h}) is @samp{"\t.size\t"}; on other
for your system. If you need your own custom definitions of those
macros, or if you do not need explicit symbol sizes at all, do not
define this macro.
+@end defmac
-@findex ASM_OUTPUT_SIZE_DIRECTIVE
-@item ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size})
+@defmac ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} a directive telling the assembler that the size of the
symbol @var{name} is @var{size}. @var{size} is a @code{HOST_WIDE_INT}.
If you define @code{SIZE_ASM_OP}, a default definition of this macro is
provided.
+@end defmac
-@findex ASM_OUTPUT_MEASURED_SIZE
-@item ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} a directive telling the assembler to calculate the size of
the symbol @var{name} by subtracting its address from the current
the difference between this and another symbol. If your assembler does
not recognize @samp{.} or cannot do calculations with it, you will need
to redefine @code{ASM_OUTPUT_MEASURED_SIZE} to use some other technique.
+@end defmac
-@findex TYPE_ASM_OP
-@item TYPE_ASM_OP
+@defmac TYPE_ASM_OP
A C string containing the appropriate assembler directive to specify the
type of a symbol, without any arguments. On systems that use ELF, the
default (in @file{config/elfos.h}) is @samp{"\t.type\t"}; on other
@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
custom definition of this macro, or if you do not need explicit symbol
types at all, do not define this macro.
+@end defmac
-@findex TYPE_OPERAND_FMT
-@item TYPE_OPERAND_FMT
+@defmac TYPE_OPERAND_FMT
A C string which specifies (using @code{printf} syntax) the format of
the second operand to @code{TYPE_ASM_OP}. On systems that use ELF, the
default (in @file{config/elfos.h}) is @samp{"@@%s"}; on other systems,
@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
custom definition of this macro, or if you do not need explicit symbol
types at all, do not define this macro.
+@end defmac
-@findex ASM_OUTPUT_TYPE_DIRECTIVE
-@item ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type})
+@defmac ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} a directive telling the assembler that the type of the
symbol @var{name} is @var{type}. @var{type} is a C string; currently,
If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
definition of this macro is provided.
+@end defmac
-@findex ASM_DECLARE_FUNCTION_NAME
-@item ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
+@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of a
function which is being defined. This macro is responsible for
You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
of this macro.
+@end defmac
-@findex ASM_DECLARE_FUNCTION_SIZE
-@item ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
+@defmac ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the size of a function
which is being defined. The argument @var{name} is the name of the
You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
of this macro.
+@end defmac
-@findex ASM_DECLARE_OBJECT_NAME
-@item ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
+@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of an
initialized variable which is being defined. This macro must output the
You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} and/or
@code{ASM_OUTPUT_SIZE_DIRECTIVE} in the definition of this macro.
+@end defmac
-@findex ASM_DECLARE_REGISTER_GLOBAL
-@item ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
+@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for claiming a register @var{regno}
for a global variable @var{decl} with name @var{name}.
If you don't define this macro, that is equivalent to defining it to do
nothing.
+@end defmac
-@findex ASM_FINISH_DECLARE_OBJECT
-@item ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
+@defmac ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
A C statement (sans semicolon) to finish up declaring a variable name
once the compiler has processed its initializer fully and thus has had a
chance to determine the size of an array when controlled by an
You may wish to use @code{ASM_OUTPUT_SIZE_DIRECTIVE} and/or
@code{ASM_OUTPUT_MEASURED_SIZE} in the definition of this macro.
-@end table
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_GLOBALIZE_LABEL (FILE *@var{stream}, const char *@var{name})
This target hook is a function to output to the stdio stream
@code{GLOBAL_ASM_OP}.
@end deftypefn
-@table @code
-@findex ASM_WEAKEN_LABEL
-@item ASM_WEAKEN_LABEL (@var{stream}, @var{name})
+@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} some commands that will make the label @var{name} weak;
that is, available for reference from other files but only used if
If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not
support weak symbols and you should not define the @code{SUPPORTS_WEAK}
macro.
+@end defmac
-@findex ASM_WEAKEN_DECL
-@item ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
+@defmac ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and
@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function
or variable decl. If @var{value} is not @code{NULL}, this C statement
defines (equates) the weak symbol @var{name} to have the value
@var{value}. If @var{value} is @code{NULL}, it should output commands
to make @var{name} weak.
+@end defmac
-@findex SUPPORTS_WEAK
-@item SUPPORTS_WEAK
+@defmac SUPPORTS_WEAK
A C expression which evaluates to true if the target supports weak symbols.
If you don't define this macro, @file{defaults.h} provides a default
is defined, the default definition is @samp{1}; otherwise, it is
@samp{0}. Define this macro if you want to control weak symbol support
with a compiler flag such as @option{-melf}.
+@end defmac
-@findex MAKE_DECL_ONE_ONLY (@var{decl})
-@item MAKE_DECL_ONE_ONLY
+@defmac MAKE_DECL_ONE_ONLY (@var{decl})
A C statement (sans semicolon) to mark @var{decl} to be emitted as a
public symbol such that extra copies in multiple translation units will
be discarded by the linker. Define this macro if your object file
format provides support for this concept, such as the @samp{COMDAT}
section flags in the Microsoft Windows PE/COFF format, and this support
requires changes to @var{decl}, such as putting it in a separate section.
+@end defmac
-@findex SUPPORTS_ONE_ONLY
-@item SUPPORTS_ONE_ONLY
+@defmac SUPPORTS_ONE_ONLY
A C expression which evaluates to true if the target supports one-only
semantics.
you want to control one-only symbol support with a compiler flag, or if
setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to
be emitted as one-only.
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_ASSEMBLE_VISIBILITY (tree @var{decl}, const char *@var{visibility})
This target hook is a function to output to @var{asm_out_file} some
hidden, protected or internal visibility as specified by @var{visibility}.
@end deftypefn
-@findex ASM_OUTPUT_EXTERNAL
-@item ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
+@defmac ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name of an external
symbol named @var{name} which is referenced in this compilation but
This macro need not be defined if it does not need to output anything.
The GNU assembler and most Unix assemblers don't require anything.
+@end defmac
-@findex ASM_OUTPUT_EXTERNAL_LIBCALL
-@item ASM_OUTPUT_EXTERNAL_LIBCALL (@var{stream}, @var{symref})
+@defmac ASM_OUTPUT_EXTERNAL_LIBCALL (@var{stream}, @var{symref})
A C statement (sans semicolon) to output on @var{stream} an assembler
pseudo-op to declare a library function name external. The name of the
library function is given by @var{symref}, which has type @code{rtx} and
This macro need not be defined if it does not need to output anything.
The GNU assembler and most Unix assemblers don't require anything.
+@end defmac
-@findex ASM_OUTPUT_LABELREF
-@item ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} a reference in assembler syntax to a label named
@var{name}. This should add @samp{_} to the front of the name, if that
is customary on your operating system, as it is in most Berkeley Unix
systems. This macro is used in @code{assemble_name}.
+@end defmac
-@findex ASM_OUTPUT_SYMBOL_REF
-@item ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
+@defmac ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
A C statement (sans semicolon) to output a reference to
@code{SYMBOL_REF} @var{sym}. If not defined, @code{assemble_name}
will be used to output the name of the symbol. This macro may be used
to modify the way a symbol is referenced depending on information
encoded by @code{TARGET_ENCODE_SECTION_INFO}.
+@end defmac
-@findex ASM_OUTPUT_LABEL_REF
-@item ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
+@defmac ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
A C statement (sans semicolon) to output a reference to @var{buf}, the
result of @code{ASM_GENERATE_INTERNAL_LABEL}. If not defined,
@code{assemble_name} will be used to output the name of the symbol.
specifier that calls it; the intention is that this macro should be set
when it is necessary to output a label differently when its address is
being taken.
+@end defmac
-@findex ASM_OUTPUT_INTERNAL_LABEL
-@item ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{prefix}, @var{num})
-A C statement to output to the stdio stream @var{stream} a label whose
-name is made from the string @var{prefix} and the number @var{num}.
+@deftypefn {Target Hook} void TARGET_ASM_INTERNAL_LABEL (FILE *@var{stream}, const char *@var{prefix}, unsigned long @var{labelno})
+A function to output to the stdio stream @var{stream} a label whose
+name is made from the string @var{prefix} and the number @var{labelno}.
It is absolutely essential that these labels be distinct from the labels
used for user-level functions and variables. Otherwise, certain programs
beginning of a label has this effect. You should find out what
convention your system uses, and follow it.
-The usual definition of this macro is as follows:
-
-@example
-fprintf (@var{stream}, "L%s%d:\n", @var{prefix}, @var{num})
-@end example
+The default version of this function utilizes ASM_GENERATE_INTERNAL_LABEL.
+@end deftypefn
-@findex ASM_OUTPUT_DEBUG_LABEL
-@item ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
+@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
A C statement to output to the stdio stream @var{stream} a debug info
label whose name is made from the string @var{prefix} and the number
@var{num}. This is useful for VLIW targets, where debug info labels
bundles, but debug info labels can occur in the middle of instruction
bundles.
-If this macro is not defined, then @code{ASM_OUTPUT_INTERNAL_LABEL} will be
+If this macro is not defined, then @code{(*targetm.asm_out.internal_label)} will be
used.
+@end defmac
-@findex ASM_GENERATE_INTERNAL_LABEL
-@item ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
+@defmac ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
A C statement to store into the string @var{string} a label whose name
is made from the string @var{prefix} and the number @var{num}.
This string, when output subsequently by @code{assemble_name}, should
-produce the output that @code{ASM_OUTPUT_INTERNAL_LABEL} would produce
+produce the output that @code{(*targetm.asm_out.internal_label)} would produce
with the same @var{prefix} and @var{num}.
If the string begins with @samp{*}, then @code{assemble_name} will
to output the string, and may change it. (Of course,
@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so
you should know what it does on your machine.)
+@end defmac
-@findex ASM_FORMAT_PRIVATE_NAME
-@item ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
+@defmac ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
A C expression to assign to @var{outvar} (which is a variable of type
@code{char *}) a newly allocated string made from the string
@var{name} and the number @var{number}, with some suitable punctuation
or percent signs in assembler symbols; putting at least one of these
between the name and the number will suffice.
-@findex ASM_OUTPUT_DEF
-@item ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
+If this macro is not defined, a default definition will be provided
+which is correct for most systems.
+@end defmac
+
+@defmac ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the symbol @var{name} to have the value @var{value}.
@findex SET_ASM_OP
If @code{SET_ASM_OP} is defined, a default definition is provided which is
correct for most systems.
+@end defmac
-@findex ASM_OUTPUT_DEF_FROM_DECLS
-@item ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
+@defmac ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the symbol whose tree node is @var{decl_of_name}
to have the value of the tree node @var{decl_of_value}. This macro will
@findex SET_ASM_OP
If @code{SET_ASM_OP} is defined, a default definition is provided which is
correct for most systems.
+@end defmac
-@findex ASM_OUTPUT_WEAK_ALIAS
-@item ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
+@defmac ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the weak symbol @var{name} to have the value
@var{value}. If @var{value} is @code{NULL}, it defines @var{name} as
Define this macro if the target only supports weak aliases; define
@code{ASM_OUTPUT_DEF} instead if possible.
+@end defmac
-@findex OBJC_GEN_METHOD_LABEL
-@item OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
+@defmac OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
Define this macro to override the default assembler names used for
Objective-C methods.
On systems where the assembler can handle quoted names, you can use this
macro to provide more human-readable names.
+@end defmac
-@findex ASM_DECLARE_CLASS_REFERENCE
-@item ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name})
+@defmac ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} commands to declare that the label @var{name} is an
Objective-C class reference. This is only needed for targets whose
linkers have special support for NeXT-style runtimes.
+@end defmac
-@findex ASM_DECLARE_UNRESOLVED_REFERENCE
-@item ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name})
+@defmac ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} commands to declare that the label @var{name} is an
unresolved Objective-C class reference. This is only needed for targets
whose linkers have special support for NeXT-style runtimes.
-@end table
+@end defmac
@node Initialization
@subsection How Initialization Functions Are Handled
upon how the code in @file{crtstuff.c} is called. On systems that
support a @dfn{.init} section which is executed at program startup,
parts of @file{crtstuff.c} are compiled into that section. The
-program is linked by the @code{gcc} driver like this:
+program is linked by the @command{gcc} driver like this:
@example
ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o
Here are the macros that control how the compiler handles initialization
and termination functions:
-@table @code
-@findex INIT_SECTION_ASM_OP
-@item INIT_SECTION_ASM_OP
+@defmac INIT_SECTION_ASM_OP
If defined, a C string constant, including spacing, for the assembler
operation to identify the following data as initialization code. If not
defined, GCC will assume such a section does not exist. When you are
using special sections for initialization and termination functions, this
macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to
run the initialization functions.
+@end defmac
-@item HAS_INIT_SECTION
-@findex HAS_INIT_SECTION
+@defmac HAS_INIT_SECTION
If defined, @code{main} will not call @code{__main} as described above.
This macro should be defined for systems that control start-up code
on a symbol-by-symbol basis, such as OSF/1, and should not
be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}.
+@end defmac
-@item LD_INIT_SWITCH
-@findex LD_INIT_SWITCH
+@defmac LD_INIT_SWITCH
If defined, a C string constant for a switch that tells the linker that
the following symbol is an initialization routine.
+@end defmac
-@item LD_FINI_SWITCH
-@findex LD_FINI_SWITCH
+@defmac LD_FINI_SWITCH
If defined, a C string constant for a switch that tells the linker that
the following symbol is a finalization routine.
+@end defmac
-@item COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
+@defmac COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
If defined, a C statement that will write a function that can be
automatically called when a shared library is loaded. The function
should call @var{func}, which takes no arguments. If not defined, and
This function and the following one are used by collect2 when linking a
shared library that needs constructors or destructors, or has DWARF2
exception tables embedded in the code.
+@end defmac
-@item COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
+@defmac COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
If defined, a C statement that will write a function that can be
automatically called when a shared library is unloaded. The function
should call @var{func}, which takes no arguments. If not defined, and
the object format requires an explicit finalization function, then a
function called @code{_GLOBAL__DD} will be generated.
+@end defmac
-@item INVOKE__main
-@findex INVOKE__main
+@defmac INVOKE__main
If defined, @code{main} will call @code{__main} despite the presence of
@code{INIT_SECTION_ASM_OP}. This macro should be defined for systems
where the init section is not actually run automatically, but is still
useful for collecting the lists of constructors and destructors.
+@end defmac
-@item SUPPORTS_INIT_PRIORITY
-@findex SUPPORTS_INIT_PRIORITY
+@defmac SUPPORTS_INIT_PRIORITY
If nonzero, the C++ @code{init_priority} attribute is supported and the
compiler should emit instructions to control the order of initialization
of objects. If zero, the compiler will issue an error message upon
encountering an @code{init_priority} attribute.
-@end table
+@end defmac
@deftypefn {Target Hook} bool TARGET_HAVE_CTORS_DTORS
This value is true if the target supports some ``native'' method of
constructors, then that program normally uses @command{nm} to scan
an object file for constructor functions to be called.
-On certain kinds of systems, you can define these macros to make
+On certain kinds of systems, you can define this macro to make
@command{collect2} work faster (and, in some cases, make it work at all):
-@table @code
-@findex OBJECT_FORMAT_COFF
-@item OBJECT_FORMAT_COFF
+@defmac OBJECT_FORMAT_COFF
Define this macro if the system uses COFF (Common Object File Format)
object files, so that @command{collect2} can assume this format and scan
object files directly for dynamic constructor/destructor functions.
-@findex OBJECT_FORMAT_ROSE
-@item OBJECT_FORMAT_ROSE
-Define this macro if the system uses ROSE format object files, so that
-@command{collect2} can assume this format and scan object files directly
-for dynamic constructor/destructor functions.
-
-These macros are effective only in a native compiler; @command{collect2} as
+This macro is effective only in a native compiler; @command{collect2} as
part of a cross compiler always uses @command{nm} for the target machine.
+@end defmac
-@findex REAL_NM_FILE_NAME
-@item REAL_NM_FILE_NAME
+@defmac REAL_NM_FILE_NAME
Define this macro as a C string constant containing the file name to use
to execute @command{nm}. The default is to search the path normally for
@command{nm}.
dynamic dependencies of a given library or executable, you can define
these macros to enable support for running initialization and
termination functions in shared libraries:
+@end defmac
-@findex LDD_SUFFIX
-@item LDD_SUFFIX
+@defmac LDD_SUFFIX
Define this macro to a C string constant containing the name of the program
which lists dynamic dependencies, like @command{"ldd"} under SunOS 4.
+@end defmac
-@findex PARSE_LDD_OUTPUT
-@item PARSE_LDD_OUTPUT (@var{ptr})
+@defmac PARSE_LDD_OUTPUT (@var{ptr})
Define this macro to be C code that extracts filenames from the output
of the program denoted by @code{LDD_SUFFIX}. @var{ptr} is a variable
of type @code{char *} that points to the beginning of a line of output
from @code{LDD_SUFFIX}. If the line lists a dynamic dependency, the
code must advance @var{ptr} to the beginning of the filename on that
line. Otherwise, it must set @var{ptr} to @code{NULL}.
-@end table
+@end defmac
@node Instruction Output
@subsection Output of Assembler Instructions
@c prevent bad page break with this line
This describes assembler instruction output.
-@table @code
-@findex REGISTER_NAMES
-@item REGISTER_NAMES
+@defmac REGISTER_NAMES
A C initializer containing the assembler's names for the machine
registers, each one as a C string constant. This is what translates
register numbers in the compiler into assembler language.
+@end defmac
-@findex ADDITIONAL_REGISTER_NAMES
-@item ADDITIONAL_REGISTER_NAMES
+@defmac ADDITIONAL_REGISTER_NAMES
If defined, a C initializer for an array of structures containing a name
and a register number. This macro defines additional names for hard
registers, thus allowing the @code{asm} option in declarations to refer
to registers using alternate names.
+@end defmac
-@findex ASM_OUTPUT_OPCODE
-@item ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
+@defmac ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
Define this macro if you are using an unusual assembler that
requires different names for the machine instructions.
If the macro definition does nothing, the instruction is output
in the usual way.
+@end defmac
-@findex FINAL_PRESCAN_INSN
-@item FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
+@defmac FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
If defined, a C statement to be executed just prior to the output of
assembler code for @var{insn}, to modify the extracted operands so
they will be output differently.
writing conditional output routines in those patterns.
If this macro is not defined, it is equivalent to a null statement.
+@end defmac
-@findex FINAL_PRESCAN_LABEL
-@item FINAL_PRESCAN_LABEL
+@defmac FINAL_PRESCAN_LABEL
If defined, @code{FINAL_PRESCAN_INSN} will be called on each
@code{CODE_LABEL}. In that case, @var{opvec} will be a null pointer and
@var{noperands} will be zero.
+@end defmac
-@findex PRINT_OPERAND
-@item PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
+@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
A C compound statement to output to stdio stream @var{stream} the
assembler syntax for an instruction operand @var{x}. @var{x} is an
RTL expression.
(a @samp{%} followed by a punctuation character), this macro is called
with a null pointer for @var{x} and the punctuation character for
@var{code}.
+@end defmac
-@findex PRINT_OPERAND_PUNCT_VALID_P
-@item PRINT_OPERAND_PUNCT_VALID_P (@var{code})
+@defmac PRINT_OPERAND_PUNCT_VALID_P (@var{code})
A C expression which evaluates to true if @var{code} is a valid
punctuation character for use in the @code{PRINT_OPERAND} macro. If
@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no
punctuation characters (except for the standard one, @samp{%}) are used
in this way.
+@end defmac
-@findex PRINT_OPERAND_ADDRESS
-@item PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
+@defmac PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
A C compound statement to output to stdio stream @var{stream} the
assembler syntax for an instruction operand that is a memory reference
whose address is @var{x}. @var{x} is an RTL expression.
On some machines, the syntax for a symbolic address depends on the
section that the address refers to. On these machines, define the hook
@code{TARGET_ENCODE_SECTION_INFO} to store the information into the
-@code{symbol_ref}, and then check for it here. @xref{Assembler Format}.
+@code{symbol_ref}, and then check for it here. @xref{Assembler
+Format}.
+@end defmac
-@findex DBR_OUTPUT_SEQEND
@findex dbr_sequence_length
-@item DBR_OUTPUT_SEQEND(@var{file})
+@defmac DBR_OUTPUT_SEQEND (@var{file})
A C statement, to be executed after all slot-filler instructions have
been output. If necessary, call @code{dbr_sequence_length} to
determine the number of slots filled in a sequence (zero if not
Don't define this macro if it has nothing to do, but it is helpful in
reading assembly output if the extent of the delay sequence is made
explicit (e.g.@: with white space).
+@end defmac
@findex final_sequence
Note that output routines for instructions with delay slots must be
processing a sequence, otherwise it contains the @code{sequence} rtx
being output.
-@findex REGISTER_PREFIX
-@findex LOCAL_LABEL_PREFIX
-@findex USER_LABEL_PREFIX
-@findex IMMEDIATE_PREFIX
@findex asm_fprintf
-@item REGISTER_PREFIX
-@itemx LOCAL_LABEL_PREFIX
-@itemx USER_LABEL_PREFIX
-@itemx IMMEDIATE_PREFIX
+@defmac REGISTER_PREFIX
+@defmacx LOCAL_LABEL_PREFIX
+@defmacx USER_LABEL_PREFIX
+@defmacx IMMEDIATE_PREFIX
If defined, C string expressions to be used for the @samp{%R}, @samp{%L},
@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see
@file{final.c}). These are useful when a single @file{md} file must
support multiple assembler formats. In that case, the various @file{tm.h}
files can define these macros differently.
+@end defmac
-@item ASM_FPRINTF_EXTENSIONS(@var{file}, @var{argptr}, @var{format})
-@findex ASM_FPRINTF_EXTENSIONS
+@defmac ASM_FPRINTF_EXTENSIONS (@var{file}, @var{argptr}, @var{format})
If defined this macro should expand to a series of @code{case}
statements which will be parsed inside the @code{switch} statement of
the @code{asm_fprintf} function. This allows targets to define extra
The varargs input pointer is @var{argptr} and the rest of the format
string, starting the character after the one that is being switched
upon, is pointed to by @var{format}.
+@end defmac
-@findex ASSEMBLER_DIALECT
-@item ASSEMBLER_DIALECT
+@defmac ASSEMBLER_DIALECT
If your target supports multiple dialects of assembler language (such as
different opcodes), define this macro as a C expression that gives the
numeric index of the assembler language dialect to use, with zero as the
@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax
if the syntax variant are larger and involve such things as different
opcodes or operand order.
+@end defmac
-@findex ASM_OUTPUT_REG_PUSH
-@item ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
+@defmac ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
A C expression to output to @var{stream} some assembler code
which will push hard register number @var{regno} onto the stack.
The code need not be optimal, since this macro is used only when
profiling.
+@end defmac
-@findex ASM_OUTPUT_REG_POP
-@item ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
+@defmac ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
A C expression to output to @var{stream} some assembler code
which will pop hard register number @var{regno} off of the stack.
The code need not be optimal, since this macro is used only when
profiling.
-@end table
+@end defmac
@node Dispatch Tables
@subsection Output of Dispatch Tables
@c prevent bad page break with this line
This concerns dispatch tables.
-@table @code
@cindex dispatch table
-@findex ASM_OUTPUT_ADDR_DIFF_ELT
-@item ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
+@defmac ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
A C statement to output to the stdio stream @var{stream} an assembler
pseudo-instruction to generate a difference between two labels.
@var{value} and @var{rel} are the numbers of two internal labels. The
definitions of these labels are output using
-@code{ASM_OUTPUT_INTERNAL_LABEL}, and they must be printed in the same
+@code{(*targetm.asm_out.internal_label)}, and they must be printed in the same
way here. For example,
@example
will also use this macro on all machines when producing PIC@.
@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the
mode and flags can be read.
+@end defmac
-@findex ASM_OUTPUT_ADDR_VEC_ELT
-@item ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
+@defmac ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
This macro should be provided on machines where the addresses
in a dispatch table are absolute.
The definition should be a C statement to output to the stdio stream
@var{stream} an assembler pseudo-instruction to generate a reference to
a label. @var{value} is the number of an internal label whose
-definition is output using @code{ASM_OUTPUT_INTERNAL_LABEL}.
+definition is output using @code{(*targetm.asm_out.internal_label)}.
For example,
@example
fprintf (@var{stream}, "\t.word L%d\n", @var{value})
@end example
+@end defmac
-@findex ASM_OUTPUT_CASE_LABEL
-@item ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
+@defmac ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
Define this if the label before a jump-table needs to be output
specially. The first three arguments are the same as for
-@code{ASM_OUTPUT_INTERNAL_LABEL}; the fourth argument is the
+@code{(*targetm.asm_out.internal_label)}; the fourth argument is the
jump-table which follows (a @code{jump_insn} containing an
@code{addr_vec} or @code{addr_diff_vec}).
for the table.
If this macro is not defined, these labels are output with
-@code{ASM_OUTPUT_INTERNAL_LABEL}.
+@code{(*targetm.asm_out.internal_label)}.
+@end defmac
-@findex ASM_OUTPUT_CASE_END
-@item ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
+@defmac ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
Define this if something special must be output at the end of a
jump-table. The definition should be a C statement to be executed
after the assembler code for the table is written. It should write
If this macro is not defined, nothing special is output at the end of
the jump-table.
-@end table
+@end defmac
@node Exception Region Output
@subsection Assembler Commands for Exception Regions
This describes commands marking the start and the end of an exception
region.
-@table @code
-@findex EH_FRAME_SECTION_NAME
-@item EH_FRAME_SECTION_NAME
+@defmac EH_FRAME_SECTION_NAME
If defined, a C string constant for the name of the section containing
exception handling frame unwind information. If not defined, GCC will
provide a default definition if the target supports named sections.
You should define this symbol if your target supports DWARF 2 frame
unwind information and the default definition does not work.
+@end defmac
-@findex EH_FRAME_IN_DATA_SECTION
-@item EH_FRAME_IN_DATA_SECTION
+@defmac EH_FRAME_IN_DATA_SECTION
If defined, DWARF 2 frame unwind information will be placed in the
data section even though the target supports named sections. This
might be necessary, for instance, if the system linker does garbage
Do not define this macro unless @code{TARGET_ASM_NAMED_SECTION} is
also defined.
+@end defmac
-@findex MASK_RETURN_ADDR
-@item MASK_RETURN_ADDR
+@defmac MASK_RETURN_ADDR
An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so
that it does not contain any extraneous set bits in it.
+@end defmac
-@findex DWARF2_UNWIND_INFO
-@item DWARF2_UNWIND_INFO
+@defmac DWARF2_UNWIND_INFO
Define this macro to 0 if your target supports DWARF 2 frame unwind
information, but it does not yet work with exception handling.
Otherwise, if your target supports this information (if it defines
If this macro is defined to anything, the DWARF 2 unwinder will be used
instead of inline unwinders and @code{__unwind_function} in the non-@code{setjmp} case.
+@end defmac
-@findex DWARF_CIE_DATA_ALIGNMENT
-@item DWARF_CIE_DATA_ALIGNMENT
+@defmac DWARF_CIE_DATA_ALIGNMENT
This macro need only be defined if the target might save registers in the
function prologue at an offset to the stack pointer that is not aligned to
@code{UNITS_PER_WORD}. The definition should be the negative minimum
alignment if @code{STACK_GROWS_DOWNWARD} is defined, and the positive
minimum alignment otherwise. @xref{SDB and DWARF}. Only applicable if
the target supports DWARF 2 frame unwind information.
-
-@end table
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_EXCEPTION_SECTION ()
If defined, a function that switches to the section in which the main
true otherwise.
@end deftypevar
+@deftypefn {Target Hook} rtx TARGET_DWARF_REGISTER_SPAN (rtx @var{reg})
+Given a register, this hook should return a parallel of registers to
+represent where to find the register pieces. Define this hook if the
+register and its mode are represented in Dwarf in non-contiguous
+locations, or if the register should be represented in more than one
+register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.
+If not defined, the default is to return @code{NULL_RTX}.
+@end deftypefn
+
@node Alignment Output
@subsection Assembler Commands for Alignment
@c prevent bad page break with this line
This describes commands for alignment.
-@table @code
-@findex JUMP_ALIGN
-@item JUMP_ALIGN (@var{label})
+@defmac JUMP_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}, which is
a common destination of jumps and has no fallthru incoming edge.
to set the variable @var{align_jumps} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation.
+@end defmac
-@findex LABEL_ALIGN_AFTER_BARRIER
-@item LABEL_ALIGN_AFTER_BARRIER (@var{label})
+@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label})
The alignment (log base 2) to put in front of @var{label}, which follows
a @code{BARRIER}.
This macro need not be defined if you don't want any special alignment
to be done at such a time. Most machine descriptions do not currently
define the macro.
+@end defmac
-@findex LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
-@item LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
+@defmac LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
The maximum number of bytes to skip when applying
@code{LABEL_ALIGN_AFTER_BARRIER}. This works only if
@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex LOOP_ALIGN
-@item LOOP_ALIGN (@var{label})
+@defmac LOOP_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}, which follows
a @code{NOTE_INSN_LOOP_BEG} note.
to set the variable @code{align_loops} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation.
+@end defmac
-@findex LOOP_ALIGN_MAX_SKIP
-@item LOOP_ALIGN_MAX_SKIP
+@defmac LOOP_ALIGN_MAX_SKIP
The maximum number of bytes to skip when applying @code{LOOP_ALIGN}.
This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex LABEL_ALIGN
-@item LABEL_ALIGN (@var{label})
+@defmac LABEL_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}.
If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment,
the maximum of the specified values is used.
to set the variable @code{align_labels} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation.
+@end defmac
-@findex LABEL_ALIGN_MAX_SKIP
-@item LABEL_ALIGN_MAX_SKIP
+@defmac LABEL_ALIGN_MAX_SKIP
The maximum number of bytes to skip when applying @code{LABEL_ALIGN}.
This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex ASM_OUTPUT_SKIP
-@item ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
+@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
A C statement to output to the stdio stream @var{stream} an assembler
instruction to advance the location counter by @var{nbytes} bytes.
Those bytes should be zero when loaded. @var{nbytes} will be a C
expression of type @code{int}.
+@end defmac
-@findex ASM_NO_SKIP_IN_TEXT
-@item ASM_NO_SKIP_IN_TEXT
+@defmac ASM_NO_SKIP_IN_TEXT
Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the
text section because it fails to put zeros in the bytes that are skipped.
This is true on many Unix systems, where the pseudo--op to skip bytes
produces no-op instructions rather than zeros when used in the text
section.
+@end defmac
-@findex ASM_OUTPUT_ALIGN
-@item ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
+@defmac ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
A C statement to output to the stdio stream @var{stream} an assembler
command to advance the location counter to a multiple of 2 to the
@var{power} bytes. @var{power} will be a C expression of type @code{int}.
+@end defmac
+
+@defmac ASM_OUTPUT_ALIGN_WITH_NOP (@var{stream}, @var{power})
+Like @code{ASM_OUTPUT_ALIGN}, except that the ``nop'' instruction is used
+for padding, if necessary.
+@end defmac
-@findex ASM_OUTPUT_MAX_SKIP_ALIGN
-@item ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
+@defmac ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
A C statement to output to the stdio stream @var{stream} an assembler
command to advance the location counter to a multiple of 2 to the
@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to
satisfy the alignment request. @var{power} and @var{max_skip} will be
a C expression of type @code{int}.
-@end table
+@end defmac
@need 3000
@node Debugging Info
@c prevent bad page break with this line
These macros affect all debugging formats.
-@table @code
-@findex DBX_REGISTER_NUMBER
-@item DBX_REGISTER_NUMBER (@var{regno})
+@defmac DBX_REGISTER_NUMBER (@var{regno})
A C expression that returns the DBX register number for the compiler
register number @var{regno}. In the default macro provided, the value
of this expression will be @var{regno} itself. But sometimes there are
If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that
does not preserve register pairs, then what you must do instead is
redefine the actual register numbering scheme.
+@end defmac
-@findex DEBUGGER_AUTO_OFFSET
-@item DEBUGGER_AUTO_OFFSET (@var{x})
+@defmac DEBUGGER_AUTO_OFFSET (@var{x})
A C expression that returns the integer offset value for an automatic
variable having address @var{x} (an RTL expression). The default
computation assumes that @var{x} is based on the frame-pointer and
that produce debugging output for DBX or COFF-style debugging output
for SDB and allow the frame-pointer to be eliminated when the
@option{-g} options is used.
+@end defmac
-@findex DEBUGGER_ARG_OFFSET
-@item DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
+@defmac DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
A C expression that returns the integer offset value for an argument
having address @var{x} (an RTL expression). The nominal offset is
@var{offset}.
+@end defmac
-@findex PREFERRED_DEBUGGING_TYPE
-@item PREFERRED_DEBUGGING_TYPE
+@defmac PREFERRED_DEBUGGING_TYPE
A C expression that returns the type of debugging output GCC should
produce when the user specifies just @option{-g}. Define
this if you have arranged for GCC to support more than one format of
user can always get a specific type of output by using @option{-gstabs},
@option{-gcoff}, @option{-gdwarf-1}, @option{-gdwarf-2}, @option{-gxcoff},
or @option{-gvms}.
-@end table
+@end defmac
@node DBX Options
@subsection Specific Options for DBX Output
@c prevent bad page break with this line
These are specific options for DBX output.
-@table @code
-@findex DBX_DEBUGGING_INFO
-@item DBX_DEBUGGING_INFO
+@defmac DBX_DEBUGGING_INFO
Define this macro if GCC should produce debugging output for DBX
in response to the @option{-g} option.
+@end defmac
-@findex XCOFF_DEBUGGING_INFO
-@item XCOFF_DEBUGGING_INFO
+@defmac XCOFF_DEBUGGING_INFO
Define this macro if GCC should produce XCOFF format debugging output
in response to the @option{-g} option. This is a variant of DBX format.
+@end defmac
-@findex DEFAULT_GDB_EXTENSIONS
-@item DEFAULT_GDB_EXTENSIONS
+@defmac DEFAULT_GDB_EXTENSIONS
Define this macro to control whether GCC should by default generate
GDB's extended version of DBX debugging information (assuming DBX-format
debugging information is enabled at all). If you don't define the
macro, the default is 1: always generate the extended information
if there is any occasion to.
+@end defmac
-@findex DEBUG_SYMS_TEXT
-@item DEBUG_SYMS_TEXT
+@defmac DEBUG_SYMS_TEXT
Define this macro if all @code{.stabs} commands should be output while
in the text section.
+@end defmac
-@findex ASM_STABS_OP
-@item ASM_STABS_OP
+@defmac ASM_STABS_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol.
If you don't define this macro, @code{"\t.stabs\t"} is used. This macro
applies only to DBX debugging information format.
+@end defmac
-@findex ASM_STABD_OP
-@item ASM_STABD_OP
+@defmac ASM_STABD_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabd\t"} to define a debugging symbol whose
value is the current location. If you don't define this macro,
@code{"\t.stabd\t"} is used. This macro applies only to DBX debugging
information format.
+@end defmac
-@findex ASM_STABN_OP
-@item ASM_STABN_OP
+@defmac ASM_STABN_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabn\t"} to define a debugging symbol with no
name. If you don't define this macro, @code{"\t.stabn\t"} is used. This
macro applies only to DBX debugging information format.
+@end defmac
-@findex DBX_NO_XREFS
-@item DBX_NO_XREFS
+@defmac DBX_NO_XREFS
Define this macro if DBX on your system does not support the construct
@samp{xs@var{tagname}}. On some systems, this construct is used to
describe a forward reference to a structure named @var{tagname}.
On other systems, this construct is not supported at all.
+@end defmac
-@findex DBX_CONTIN_LENGTH
-@item DBX_CONTIN_LENGTH
+@defmac DBX_CONTIN_LENGTH
A symbol name in DBX-format debugging information is normally
continued (split into two separate @code{.stabs} directives) when it
exceeds a certain length (by default, 80 characters). On some
must not be done. You can inhibit splitting by defining this macro
with the value zero. You can override the default splitting-length by
defining this macro as an expression for the length you desire.
+@end defmac
-@findex DBX_CONTIN_CHAR
-@item DBX_CONTIN_CHAR
+@defmac DBX_CONTIN_CHAR
Normally continuation is indicated by adding a @samp{\} character to
the end of a @code{.stabs} string when a continuation follows. To use
a different character instead, define this macro as a character
constant for the character you want to use. Do not define this macro
if backslash is correct for your system.
+@end defmac
-@findex DBX_STATIC_STAB_DATA_SECTION
-@item DBX_STATIC_STAB_DATA_SECTION
+@defmac DBX_STATIC_STAB_DATA_SECTION
Define this macro if it is necessary to go to the data section before
outputting the @samp{.stabs} pseudo-op for a non-global static
variable.
+@end defmac
-@findex DBX_TYPE_DECL_STABS_CODE
-@item DBX_TYPE_DECL_STABS_CODE
+@defmac DBX_TYPE_DECL_STABS_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a typedef. The default is @code{N_LSYM}.
+@end defmac
-@findex DBX_STATIC_CONST_VAR_CODE
-@item DBX_STATIC_CONST_VAR_CODE
+@defmac DBX_STATIC_CONST_VAR_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a static variable located in the text section. DBX format does not
provide any ``right'' way to do this. The default is @code{N_FUN}.
+@end defmac
-@findex DBX_REGPARM_STABS_CODE
-@item DBX_REGPARM_STABS_CODE
+@defmac DBX_REGPARM_STABS_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a parameter passed in registers. DBX format does not provide any
``right'' way to do this. The default is @code{N_RSYM}.
+@end defmac
-@findex DBX_REGPARM_STABS_LETTER
-@item DBX_REGPARM_STABS_LETTER
+@defmac DBX_REGPARM_STABS_LETTER
The letter to use in DBX symbol data to identify a symbol as a parameter
passed in registers. DBX format does not customarily provide any way to
do this. The default is @code{'P'}.
+@end defmac
-@findex DBX_MEMPARM_STABS_LETTER
-@item DBX_MEMPARM_STABS_LETTER
+@defmac DBX_MEMPARM_STABS_LETTER
The letter to use in DBX symbol data to identify a symbol as a stack
parameter. The default is @code{'p'}.
+@end defmac
-@findex DBX_FUNCTION_FIRST
-@item DBX_FUNCTION_FIRST
+@defmac DBX_FUNCTION_FIRST
Define this macro if the DBX information for a function and its
arguments should precede the assembler code for the function. Normally,
in DBX format, the debugging information entirely follows the assembler
code.
+@end defmac
-@findex DBX_LBRAC_FIRST
-@item DBX_LBRAC_FIRST
-Define this macro if the @code{N_LBRAC} symbol for a block should
-precede the debugging information for variables and functions defined in
-that block. Normally, in DBX format, the @code{N_LBRAC} symbol comes
-first.
-
-@findex DBX_BLOCKS_FUNCTION_RELATIVE
-@item DBX_BLOCKS_FUNCTION_RELATIVE
+@defmac DBX_BLOCKS_FUNCTION_RELATIVE
Define this macro if the value of a symbol describing the scope of a
block (@code{N_LBRAC} or @code{N_RBRAC}) should be relative to the start
of the enclosing function. Normally, GCC uses an absolute address.
+@end defmac
-@findex DBX_USE_BINCL
-@item DBX_USE_BINCL
+@defmac DBX_USE_BINCL
Define this macro if GCC should generate @code{N_BINCL} and
@code{N_EINCL} stabs for included header files, as on Sun systems. This
macro also directs GCC to output a type number as a pair of a file
number and a type number within the file. Normally, GCC does not
generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single
number for a type number.
-@end table
+@end defmac
@node DBX Hooks
@subsection Open-Ended Hooks for DBX Format
@c prevent bad page break with this line
These are hooks for DBX format.
-@table @code
-@findex DBX_OUTPUT_LBRAC
-@item DBX_OUTPUT_LBRAC (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_LBRAC (@var{stream}, @var{name})
Define this macro to say how to output to @var{stream} the debugging
information for the start of a scope level for variable names. The
argument @var{name} is the name of an assembler symbol (for use with
@code{assemble_name}) whose value is the address where the scope begins.
+@end defmac
-@findex DBX_OUTPUT_RBRAC
-@item DBX_OUTPUT_RBRAC (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_RBRAC (@var{stream}, @var{name})
Like @code{DBX_OUTPUT_LBRAC}, but for the end of a scope level.
+@end defmac
-@findex DBX_OUTPUT_NFUN
-@item DBX_OUTPUT_NFUN (@var{stream}, @var{lscope_label}, @var{decl})
+@defmac DBX_OUTPUT_NFUN (@var{stream}, @var{lscope_label}, @var{decl})
Define this macro if the target machine requires special handling to
output an @code{N_FUN} entry for the function @var{decl}.
+@end defmac
-@findex DBX_OUTPUT_ENUM
-@item DBX_OUTPUT_ENUM (@var{stream}, @var{type})
-Define this macro if the target machine requires special handling to
-output an enumeration type. The definition should be a C statement
-(sans semicolon) to output the appropriate information to @var{stream}
-for the type @var{type}.
-
-@findex DBX_OUTPUT_FUNCTION_END
-@item DBX_OUTPUT_FUNCTION_END (@var{stream}, @var{function})
+@defmac DBX_OUTPUT_FUNCTION_END (@var{stream}, @var{function})
Define this macro if the target machine requires special output at the
end of the debugging information for a function. The definition should
be a C statement (sans semicolon) to output the appropriate information
to @var{stream}. @var{function} is the @code{FUNCTION_DECL} node for
the function.
+@end defmac
-@findex DBX_OUTPUT_STANDARD_TYPES
-@item DBX_OUTPUT_STANDARD_TYPES (@var{syms})
+@defmac DBX_OUTPUT_STANDARD_TYPES (@var{syms})
Define this macro if you need to control the order of output of the
standard data types at the beginning of compilation. The argument
@var{syms} is a @code{tree} which is a chain of all the predefined
@}
@end group
@end smallexample
+@end defmac
-@findex NO_DBX_FUNCTION_END
-@item NO_DBX_FUNCTION_END
+@defmac NO_DBX_FUNCTION_END
Some stabs encapsulation formats (in particular ECOFF), cannot handle the
@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct.
On those machines, define this macro to turn this feature off without
disturbing the rest of the gdb extensions.
-
-@end table
+@end defmac
@node File Names and DBX
@subsection File Names in DBX Format
@c prevent bad page break with this line
This describes file names in DBX format.
-@table @code
-@findex DBX_WORKING_DIRECTORY
-@item DBX_WORKING_DIRECTORY
-Define this if DBX wants to have the current directory recorded in each
-object file.
-
-Note that the working directory is always recorded if GDB extensions are
-enabled.
-
-@findex DBX_OUTPUT_MAIN_SOURCE_FILENAME
-@item DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
A C statement to output DBX debugging information to the stdio stream
@var{stream} which indicates that file @var{name} is the main source
file---the file specified as the input file for compilation.
This macro need not be defined if the standard form of output
for DBX debugging information is appropriate.
+@end defmac
-@findex DBX_OUTPUT_MAIN_SOURCE_DIRECTORY
-@item DBX_OUTPUT_MAIN_SOURCE_DIRECTORY (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_MAIN_SOURCE_DIRECTORY (@var{stream}, @var{name})
A C statement to output DBX debugging information to the stdio stream
@var{stream} which indicates that the current directory during
compilation is named @var{name}.
This macro need not be defined if the standard form of output
for DBX debugging information is appropriate.
+@end defmac
-@findex DBX_OUTPUT_MAIN_SOURCE_FILE_END
-@item DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
A C statement to output DBX debugging information at the end of
compilation of the main source file @var{name}.
If you don't define this macro, nothing special is output at the end
of compilation, which is correct for most machines.
-
-@findex DBX_OUTPUT_SOURCE_FILENAME
-@item DBX_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output DBX debugging information to the stdio stream
-@var{stream} which indicates that file @var{name} is the current source
-file. This output is generated each time input shifts to a different
-source file as a result of @samp{#include}, the end of an included file,
-or a @samp{#line} command.
-
-This macro need not be defined if the standard form of output
-for DBX debugging information is appropriate.
-@end table
+@end defmac
@need 2000
@node SDB and DWARF
@c prevent bad page break with this line
Here are macros for SDB and DWARF output.
-@table @code
-@findex SDB_DEBUGGING_INFO
-@item SDB_DEBUGGING_INFO
+@defmac SDB_DEBUGGING_INFO
Define this macro if GCC should produce COFF-style debugging output
for SDB in response to the @option{-g} option.
+@end defmac
-@findex DWARF_DEBUGGING_INFO
-@item DWARF_DEBUGGING_INFO
+@defmac DWARF_DEBUGGING_INFO
Define this macro if GCC should produce dwarf format debugging output
in response to the @option{-g} option.
+@end defmac
-@findex DWARF2_DEBUGGING_INFO
-@item DWARF2_DEBUGGING_INFO
+@defmac DWARF2_DEBUGGING_INFO
Define this macro if GCC should produce dwarf version 2 format
debugging output in response to the @option{-g} option.
@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the
prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save}
as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't.
+@end defmac
-@findex DWARF2_FRAME_INFO
-@item DWARF2_FRAME_INFO
+@defmac DWARF2_FRAME_INFO
Define this macro to a nonzero value if GCC should always output
Dwarf 2 frame information. If @code{DWARF2_UNWIND_INFO}
(@pxref{Exception Region Output} is nonzero, GCC will output this
information not matter how you define @code{DWARF2_FRAME_INFO}.
+@end defmac
-@findex LINKER_DOES_NOT_WORK_WITH_DWARF2
-@item LINKER_DOES_NOT_WORK_WITH_DWARF2
+@defmac LINKER_DOES_NOT_WORK_WITH_DWARF2
Define this macro if the linker does not work with Dwarf version 2.
Normally, if the user specifies only @option{-ggdb} GCC will use Dwarf
version 2 if available; this macro disables this. See the description
of the @code{PREFERRED_DEBUGGING_TYPE} macro for more details.
+@end defmac
-@findex DWARF2_GENERATE_TEXT_SECTION_LABEL
-@item DWARF2_GENERATE_TEXT_SECTION_LABEL
+@defmac DWARF2_GENERATE_TEXT_SECTION_LABEL
By default, the Dwarf 2 debugging information generator will generate a
label to mark the beginning of the text section. If it is better simply
to use the name of the text section itself, rather than an explicit label,
to indicate the beginning of the text section, define this macro to zero.
+@end defmac
-@findex DWARF2_ASM_LINE_DEBUG_INFO
-@item DWARF2_ASM_LINE_DEBUG_INFO
+@defmac DWARF2_ASM_LINE_DEBUG_INFO
Define this macro to be a nonzero value if the assembler can generate Dwarf 2
line debug info sections. This will result in much more compact line number
tables, and hence is desirable if it works.
+@end defmac
-@findex ASM_OUTPUT_DWARF_DELTA
-@item ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
+@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
A C statement to issue assembly directives that create a difference
between the two given labels, using an integer of the given size.
+@end defmac
-@findex ASM_OUTPUT_DWARF_OFFSET
-@item ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label})
+@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label})
A C statement to issue assembly directives that create a
section-relative reference to the given label, using an integer of the
given size.
+@end defmac
-@findex ASM_OUTPUT_DWARF_PCREL
-@item ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
+@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
A C statement to issue assembly directives that create a self-relative
reference to the given label, using an integer of the given size.
+@end defmac
-@findex PUT_SDB_@dots{}
-@item PUT_SDB_@dots{}
+@defmac PUT_SDB_@dots{}
Define these macros to override the assembler syntax for the special
SDB assembler directives. See @file{sdbout.c} for a list of these
macros and their arguments. If the standard syntax is used, you need
not define them yourself.
+@end defmac
-@findex SDB_DELIM
-@item SDB_DELIM
+@defmac SDB_DELIM
Some assemblers do not support a semicolon as a delimiter, even between
SDB assembler directives. In that case, define this macro to be the
delimiter to use (usually @samp{\n}). It is not necessary to define
a new set of @code{PUT_SDB_@var{op}} macros if this is the only change
required.
+@end defmac
-@findex SDB_GENERATE_FAKE
-@item SDB_GENERATE_FAKE
+@defmac SDB_GENERATE_FAKE
Define this macro to override the usual method of constructing a dummy
name for anonymous structure and union types. See @file{sdbout.c} for
more information.
+@end defmac
-@findex SDB_ALLOW_UNKNOWN_REFERENCES
-@item SDB_ALLOW_UNKNOWN_REFERENCES
+@defmac SDB_ALLOW_UNKNOWN_REFERENCES
Define this macro to allow references to unknown structure,
union, or enumeration tags to be emitted. Standard COFF does not
allow handling of unknown references, MIPS ECOFF has support for
it.
+@end defmac
-@findex SDB_ALLOW_FORWARD_REFERENCES
-@item SDB_ALLOW_FORWARD_REFERENCES
+@defmac SDB_ALLOW_FORWARD_REFERENCES
Define this macro to allow references to structure, union, or
enumeration tags that have not yet been seen to be handled. Some
assemblers choke if forward tags are used, while some require it.
-@end table
+@end defmac
@need 2000
@node VMS Debug
@c prevent bad page break with this line
Here are macros for VMS debug format.
-@table @code
-@findex VMS_DEBUGGING_INFO
-@item VMS_DEBUGGING_INFO
+@defmac VMS_DEBUGGING_INFO
Define this macro if GCC should produce debugging output for VMS
in response to the @option{-g} option. The default behavior for VMS
is to generate minimal debug info for a traceback in the absence of
@option{-g} unless explicitly overridden with @option{-g0}. This
behavior is controlled by @code{OPTIMIZATION_OPTIONS} and
@code{OVERRIDE_OPTIONS}.
-@end table
+@end defmac
@node Floating Point
@section Cross Compilation and Floating Point
Tests whether @var{x} is less than @var{y}.
@end deftypefn
-@findex ldexp
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_LDEXP (REAL_VALUE_TYPE @var{x}, int @var{scale})
-Multiplies @var{x} by 2 raised to the power @var{scale}.
-@end deftypefn
-
@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x})
Truncates @var{x} to a signed integer, rounding toward zero.
@end deftypefn
@var{x} is negative, returns zero.
@end deftypefn
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_RNDZINT (REAL_VALUE_TYPE @var{x})
-Rounds the target-machine floating point value @var{x} towards zero to an
-integer value, but leaves it represented as a floating point number.
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_UNSIGNED_RNDZINT (REAL_VALUE_TYPE @var{x})
-Rounds the target-machine floating point value @var{x} towards zero to an
-unsigned integer value, but leaves it represented as a floating point
-number. If @var{x} is negative, returns (positive) zero.
-@end deftypefn
-
@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, enum machine_mode @var{mode})
Converts @var{string} into a floating point number in the target machine's
representation for mode @var{mode}. This routine can handle both
@end deftypefn
@deftypefn Macro void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE @var{x}, HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, enum machine_mode @var{mode})
-@findex REAL_VALUE_FROM_INT
Converts a double-precision integer found in @var{low} and @var{high},
into a floating point value which is then stored into @var{x}. The
value is truncated to fit in mode @var{mode}.
@cindex mode switching
The following macros control mode switching optimizations:
-@table @code
-@findex OPTIMIZE_MODE_SWITCHING
-@item OPTIMIZE_MODE_SWITCHING (@var{entity})
+@defmac OPTIMIZE_MODE_SWITCHING (@var{entity})
Define this macro if the port needs extra instructions inserted for mode
switching in an optimizing compilation.
operation, this bit has to be set. Changing the PR bit requires a general
purpose register as a scratch register, hence these FPSCR sets have to
be inserted before reload, i.e.@: you can't put this into instruction emitting
-or @code{MACHINE_DEPENDENT_REORG}.
+or @code{TARGET_MACHINE_DEPENDENT_REORG}.
You can have multiple entities that are mode-switched, and select at run time
which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should
@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
@code{NORMAL_MODE} is optional.
+@end defmac
-@findex NUM_MODES_FOR_MODE_SWITCHING
-@item NUM_MODES_FOR_MODE_SWITCHING
+@defmac NUM_MODES_FOR_MODE_SWITCHING
If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as
initializer for an array of integers. Each initializer element
N refers to an entity that needs mode switching, and specifies the number
In macros that take mode arguments / yield a mode result, modes are
represented as numbers 0 @dots{} N @minus{} 1. N is used to specify that no mode
switch is needed / supplied.
+@end defmac
-@findex MODE_NEEDED
-@item MODE_NEEDED (@var{entity}, @var{insn})
+@defmac MODE_NEEDED (@var{entity}, @var{insn})
@var{entity} is an integer specifying a mode-switched entity. If
@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to
return an integer value not larger than the corresponding element in
@code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must
be switched into prior to the execution of @var{insn}.
+@end defmac
-@findex NORMAL_MODE
-@item NORMAL_MODE (@var{entity})
+@defmac NORMAL_MODE (@var{entity})
If this macro is defined, it is evaluated for every @var{entity} that needs
mode switching. It should evaluate to an integer, which is a mode that
@var{entity} is assumed to be switched to at function entry and exit.
+@end defmac
-@findex MODE_PRIORITY_TO_MODE
-@item MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
+@defmac MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
This macro specifies the order in which modes for @var{entity} are processed.
0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the
lowest. The value of the macro should be an integer designating a mode
for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode}
(@var{entity}, @var{n}) shall be a bijection in 0 @dots{}
@code{num_modes_for_mode_switching[@var{entity}] - 1}.
+@end defmac
-@findex EMIT_MODE_SET
-@item EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
+@defmac EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
-@end table
+@end defmac
@node Target Attributes
@section Defining target-specific uses of @code{__attribute__}
There is one macro used in defining the MIPS coprocessor interface which
you may want to override in subtargets; it is described below.
-@table @code
-
-@item ALL_COP_ADDITIONAL_REGISTER_NAMES
-@findex ALL_COP_ADDITIONAL_REGISTER_NAMES
+@defmac ALL_COP_ADDITIONAL_REGISTER_NAMES
A comma-separated list (with leading comma) of pairs describing the
alternate names of coprocessor registers. The format of each entry should be
@smallexample
@{ @var{alternatename}, @var{register_number}@}
@end smallexample
Default: empty.
-
-@end table
+@end defmac
@node Misc
@section Miscellaneous Parameters
@c prevent bad page break with this line
Here are several miscellaneous parameters.
-@table @code
-@item PREDICATE_CODES
-@findex PREDICATE_CODES
+@defmac PREDICATE_CODES
Define this if you have defined special-purpose predicates in the file
@file{@var{machine}.c}. This macro is called within an initializer of an
array of structures. The first field in the structure is the name of a
For each predicate function named in @code{PREDICATE_CODES}, a
declaration will be generated in @file{insn-codes.h}.
+@end defmac
-@item SPECIAL_MODE_PREDICATES
-@findex SPECIAL_MODE_PREDICATES
+@defmac SPECIAL_MODE_PREDICATES
Define this if you have special predicates that know special things
about modes. Genrecog will warn about certain forms of
@code{match_operand} without a mode; if the operand predicate is
#define SPECIAL_MODE_PREDICATES \
"ext_register_operand",
@end smallexample
+@end defmac
-@findex CASE_VECTOR_MODE
-@item CASE_VECTOR_MODE
+@defmac CASE_VECTOR_MODE
An alias for a machine mode name. This is the machine mode that
elements of a jump-table should have.
+@end defmac
-@findex CASE_VECTOR_SHORTEN_MODE
-@item CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
+@defmac CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
Optional: return the preferred mode for an @code{addr_diff_vec}
when the minimum and maximum offset are known. If you define this,
it enables extra code in branch shortening to deal with @code{addr_diff_vec}.
make the alignment for @code{addr_diff_vec} explicit.
The @var{body} argument is provided so that the offset_unsigned and scale
flags can be updated.
+@end defmac
-@findex CASE_VECTOR_PC_RELATIVE
-@item CASE_VECTOR_PC_RELATIVE
+@defmac CASE_VECTOR_PC_RELATIVE
Define this macro to be a C expression to indicate when jump-tables
should contain relative addresses. If jump-tables never contain
relative addresses, then you need not define this macro.
+@end defmac
-@findex CASE_DROPS_THROUGH
-@item CASE_DROPS_THROUGH
+@defmac CASE_DROPS_THROUGH
Define this if control falls through a @code{case} insn when the index
value is out of range. This means the specified default-label is
actually ignored by the @code{case} insn proper.
+@end defmac
-@findex CASE_VALUES_THRESHOLD
-@item CASE_VALUES_THRESHOLD
+@defmac CASE_VALUES_THRESHOLD
Define this to be the smallest number of different values for which it
is best to use a jump-table instead of a tree of conditional branches.
The default is four for machines with a @code{casesi} instruction and
five otherwise. This is best for most machines.
+@end defmac
+
+@defmac CASE_USE_BIT_TESTS
+Define this macro to be a C expression to indicate whether C switch
+statements may be implemented by a sequence of bit tests. This is
+advantageous on processors that can efficiently implement left shift
+of 1 by the number of bits held in a register, but inappropriate on
+targets that would require a loop. By default, this macro returns
+@code{true} if the target defines an @code{ashlsi3} pattern, and
+@code{false} otherwise.
+@end defmac
-@findex WORD_REGISTER_OPERATIONS
-@item WORD_REGISTER_OPERATIONS
+@defmac WORD_REGISTER_OPERATIONS
Define this macro if operations between registers with integral mode
smaller than a word are always performed on the entire register.
Most RISC machines have this property and most CISC machines do not.
+@end defmac
-@findex LOAD_EXTEND_OP
-@item LOAD_EXTEND_OP (@var{mode})
+@defmac LOAD_EXTEND_OP (@var{mode})
Define this macro to be a C expression indicating when insns that read
memory in @var{mode}, an integral mode narrower than a word, set the
bits outside of @var{mode} to be either the sign-extension or the
value in this case. Do not define this macro if it would always return
@code{NIL}. On machines where this macro is defined, you will normally
define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}.
+@end defmac
-@findex SHORT_IMMEDIATES_SIGN_EXTEND
-@item SHORT_IMMEDIATES_SIGN_EXTEND
+@defmac SHORT_IMMEDIATES_SIGN_EXTEND
Define this macro if loading short immediate values into registers sign
extends.
+@end defmac
-@findex FIXUNS_TRUNC_LIKE_FIX_TRUNC
-@item FIXUNS_TRUNC_LIKE_FIX_TRUNC
+@defmac FIXUNS_TRUNC_LIKE_FIX_TRUNC
Define this macro if the same instructions that convert a floating
point number to a signed fixed point number also convert validly to an
unsigned one.
+@end defmac
-@findex MOVE_MAX
-@item MOVE_MAX
+@defmac MOVE_MAX
The maximum number of bytes that a single instruction can move quickly
between memory and registers or between two memory locations.
+@end defmac
-@findex MAX_MOVE_MAX
-@item MAX_MOVE_MAX
+@defmac MAX_MOVE_MAX
The maximum number of bytes that a single instruction can move quickly
between memory and registers or between two memory locations. If this
is undefined, the default is @code{MOVE_MAX}. Otherwise, it is the
constant value that is the largest value that @code{MOVE_MAX} can have
at run-time.
+@end defmac
-@findex SHIFT_COUNT_TRUNCATED
-@item SHIFT_COUNT_TRUNCATED
+@defmac SHIFT_COUNT_TRUNCATED
A C expression that is nonzero if on this machine the number of bits
actually used for the count of a shift operation is equal to the number
of bits needed to represent the size of the object being shifted. When
the implied truncation of the shift instructions.
You need not define this macro if it would always have the value of zero.
+@end defmac
-@findex TRULY_NOOP_TRUNCATION
-@item TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
+@defmac TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
A C expression which is nonzero if on this machine it is safe to
``convert'' an integer of @var{inprec} bits to one of @var{outprec}
bits (where @var{outprec} is smaller than @var{inprec}) by merely
modes for which @code{MODES_TIEABLE_P} is 0, suboptimal code can result.
If this is the case, making @code{TRULY_NOOP_TRUNCATION} return 0 in
such cases may improve things.
+@end defmac
-@findex STORE_FLAG_VALUE
-@item STORE_FLAG_VALUE
+@defmac STORE_FLAG_VALUE
A C expression describing the value returned by a comparison operator
with an integral mode and stored by a store-flag instruction
(@samp{s@var{cond}}) when the condition is true. This description must
@file{rs6000.md} for some examples. The GNU Superoptizer can be used to
find such instruction sequences on other machines.
-You need not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
-instructions.
+If this macro is not defined, the default value, 1, is used. You need
+not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
+instructions, or if the value generated by these instructions is 1.
+@end defmac
-@findex FLOAT_STORE_FLAG_VALUE
-@item FLOAT_STORE_FLAG_VALUE (@var{mode})
+@defmac FLOAT_STORE_FLAG_VALUE (@var{mode})
A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is
returned when comparison operators with floating-point results are true.
Define this macro on machine that have comparison operations that return
floating-point values. If there are no such operations, do not define
this macro.
+@end defmac
+
+@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
+@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
+A C expression that evaluates to true if the architecture defines a value
+for @code{clz} or @code{ctz} with a zero operand. If so, @var{value}
+should be set to this value. If this macro is not defined, the value of
+@code{clz} or @code{ctz} is assumed to be undefined.
+
+This macro must be defined if the target's expansion for @code{ffs}
+relies on a particular value to get correct results. Otherwise it
+is not necessary, though it may be used to optimize some corner cases.
+
+Note that regardless of this macro the ``definedness'' of @code{clz}
+and @code{ctz} at zero do @emph{not} extend to the builtin functions
+visible to the user. Thus one may be free to adjust the value at will
+to match the target expansion of these operations without fear of
+breaking the API.
+@end defmac
-@findex Pmode
-@item Pmode
+@defmac Pmode
An alias for the machine mode for pointers. On most machines, define
this to be the integer mode corresponding to the width of a hardware
pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines.
@code{POINTER_SIZE}. If it is not equal, you must define the macro
@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended
to @code{Pmode}.
+@end defmac
-@findex FUNCTION_MODE
-@item FUNCTION_MODE
+@defmac FUNCTION_MODE
An alias for the machine mode used for memory references to functions
being called, in @code{call} RTL expressions. On most machines this
should be @code{QImode}.
+@end defmac
-@findex INTEGRATE_THRESHOLD
-@item INTEGRATE_THRESHOLD (@var{decl})
+@defmac INTEGRATE_THRESHOLD (@var{decl})
A C expression for the maximum number of instructions above which the
function @var{decl} should not be inlined. @var{decl} is a
@code{FUNCTION_DECL} node.
The default definition of this macro is 64 plus 8 times the number of
arguments that the function accepts. Some people think a larger
threshold should be used on RISC machines.
+@end defmac
-@findex STDC_0_IN_SYSTEM_HEADERS
-@item STDC_0_IN_SYSTEM_HEADERS
+@defmac STDC_0_IN_SYSTEM_HEADERS
In normal operation, the preprocessor expands @code{__STDC__} to the
constant 1, to signify that GCC conforms to ISO Standard C@. On some
hosts, like Solaris, the system compiler uses a different convention,
Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host
convention when processing system header files, but when processing user
files @code{__STDC__} will always expand to 1.
+@end defmac
-@findex NO_IMPLICIT_EXTERN_C
-@item NO_IMPLICIT_EXTERN_C
+@defmac NO_IMPLICIT_EXTERN_C
Define this macro if the system header files support C++ as well as C@.
This macro inhibits the usual method of using system header files in
C++, which is to pretend that the file's contents are enclosed in
@samp{extern "C" @{@dots{}@}}.
+@end defmac
-@findex HANDLE_PRAGMA
-@item HANDLE_PRAGMA (@var{getc}, @var{ungetc}, @var{name})
-This macro is no longer supported. You must use
-@code{REGISTER_TARGET_PRAGMAS} instead.
-
-@findex REGISTER_TARGET_PRAGMAS
@findex #pragma
@findex pragma
-@item REGISTER_TARGET_PRAGMAS (@var{pfile})
+@defmac REGISTER_TARGET_PRAGMAS ()
Define this macro if you want to implement any target-specific pragmas.
If defined, it is a C expression which makes a series of calls to
-@code{cpp_register_pragma} for each pragma, with @var{pfile} passed as
-the first argument to to these functions. The macro may also do any
+@code{c_register_pragma} for each pragma. The macro may also do any
setup required for the pragmas.
The primary reason to define this macro is to provide compatibility with
Preprocessor macros that appear on pragma lines are not expanded. All
@samp{#pragma} directives that do not match any registered pragma are
silently ignored, unless the user specifies @option{-Wunknown-pragmas}.
+@end defmac
-@deftypefun void cpp_register_pragma (cpp_reader *@var{pfile}, const char *@var{space}, const char *@var{name}, void (*@var{callback}) (cpp_reader *))
+@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-Each call to @code{cpp_register_pragma} establishes one pragma. The
+Each call to @code{c_register_pragma} establishes one pragma. The
@var{callback} routine will be called when the preprocessor encounters a
pragma of the form
on to cpplib's functions if necessary. You can lex tokens after the
@var{name} by calling @code{c_lex}. Tokens that are not read by the
callback will be silently ignored. The end of the line is indicated by
-a token of type @code{CPP_EOF}.
+a token of type @code{CPP_EOF}
For an example use of this routine, see @file{c4x.h} and the callback
routines defined in @file{c4x-c.c}.
how to build this object file.
@end deftypefun
-@findex HANDLE_SYSV_PRAGMA
@findex #pragma
@findex pragma
-@item HANDLE_SYSV_PRAGMA
+@defmac HANDLE_SYSV_PRAGMA
Define this macro (to a value of 1) if you want the System V style
pragmas @samp{#pragma pack(<n>)} and @samp{#pragma weak <name>
[=<value>]} to be supported by gcc.
@samp{__packed__} @code{__attribute__}s do. A pack value of zero resets
the behavior to the default.
+A subtlety for Microsoft Visual C/C++ style bit-field packing
+(e.g. -mms-bitfields) for targets that support it:
+When a bit-field is inserted into a packed record, the whole size
+of the underlying type is used by one or more same-size adjacent
+bit-fields (that is, if its long:3, 32 bits is used in the record,
+and any additional adjacent long bit-fields are packed into the same
+chunk of 32 bits. However, if the size changes, a new field of that
+size is allocated).
+
+If both MS bit-fields and @samp{__attribute__((packed))} are used,
+the latter will take precedence. If @samp{__attribute__((packed))} is
+used on a single field when MS bit-fields are in use, it will take
+precedence for that field, but the alignment of the rest of the structure
+may affect its placement.
+
The weak pragma only works if @code{SUPPORTS_WEAK} and
@code{ASM_WEAKEN_LABEL} are defined. If enabled it allows the creation
of specifically named weak labels, optionally with a value.
+@end defmac
-@findex HANDLE_PRAGMA_PACK_PUSH_POP
@findex #pragma
@findex pragma
-@item HANDLE_PRAGMA_PACK_PUSH_POP
+@defmac HANDLE_PRAGMA_PACK_PUSH_POP
Define this macro (to a value of 1) if you want to support the Win32
style pragmas @samp{#pragma pack(push,@var{n})} and @samp{#pragma
pack(pop)}. The @samp{pack(push,@var{n})} pragma specifies the maximum alignment
invocations of this pragma cause the previous values to be stacked, so
that invocations of @samp{#pragma pack(pop)} will return to the previous
value.
+@end defmac
-@findex DOLLARS_IN_IDENTIFIERS
-@item DOLLARS_IN_IDENTIFIERS
-Define this macro to control use of the character @samp{$} in identifier
-names. 0 means @samp{$} is not allowed by default; 1 means it is allowed.
-1 is the default; there is no need to define this macro in that case.
-This macro controls the compiler proper; it does not affect the preprocessor.
+@defmac DOLLARS_IN_IDENTIFIERS
+Define this macro to control use of the character @samp{$} in
+identifier names for the C family of languages. 0 means @samp{$} is
+not allowed by default; 1 means it is allowed. 1 is the default;
+there is no need to define this macro in that case.
+@end defmac
-@findex NO_DOLLAR_IN_LABEL
-@item NO_DOLLAR_IN_LABEL
+@defmac NO_DOLLAR_IN_LABEL
Define this macro if the assembler does not accept the character
@samp{$} in label names. By default constructors and destructors in
G++ have @samp{$} in the identifiers. If this macro is defined,
@samp{.} is used instead.
+@end defmac
-@findex NO_DOT_IN_LABEL
-@item NO_DOT_IN_LABEL
+@defmac NO_DOT_IN_LABEL
Define this macro if the assembler does not accept the character
@samp{.} in label names. By default constructors and destructors in G++
have names that use @samp{.}. If this macro is defined, these names
are rewritten to avoid @samp{.}.
+@end defmac
-@findex DEFAULT_MAIN_RETURN
-@item DEFAULT_MAIN_RETURN
+@defmac DEFAULT_MAIN_RETURN
Define this macro if the target system expects every program's @code{main}
function to return a standard ``success'' value by default (if no other
value is explicitly returned).
The definition should be a C statement (sans semicolon) to generate the
appropriate rtl instructions. It is used only when compiling the end of
@code{main}.
+@end defmac
-@item NEED_ATEXIT
-@findex NEED_ATEXIT
-Define this if the target system lacks the function @code{atexit}
-from the ISO C standard. If this macro is defined, a default definition
-will be provided to support C++. If @code{ON_EXIT} is not defined,
-a default @code{exit} function will also be provided.
-
-@item ON_EXIT
-@findex ON_EXIT
-Define this macro if the target has another way to implement atexit
-functionality without replacing @code{exit}. For instance, SunOS 4 has
-a similar @code{on_exit} library function.
-
-The definition should be a functional macro which can be used just like
-the @code{atexit} function.
-
-@item EXIT_BODY
-@findex EXIT_BODY
-Define this if your @code{exit} function needs to do something
-besides calling an external function @code{_cleanup} before
-terminating with @code{_exit}. The @code{EXIT_BODY} macro is
-only needed if @code{NEED_ATEXIT} is defined and @code{ON_EXIT} is not
-defined.
-
-@findex INSN_SETS_ARE_DELAYED
-@item INSN_SETS_ARE_DELAYED (@var{insn})
+@defmac INSN_SETS_ARE_DELAYED (@var{insn})
Define this macro as a C expression that is nonzero if it is safe for the
delay slot scheduler to place instructions in the delay slot of @var{insn},
even if they appear to use a resource set or clobbered in @var{insn}.
you should define this macro.
You need not define this macro if it would always return zero.
+@end defmac
-@findex INSN_REFERENCES_ARE_DELAYED
-@item INSN_REFERENCES_ARE_DELAYED (@var{insn})
+@defmac INSN_REFERENCES_ARE_DELAYED (@var{insn})
Define this macro as a C expression that is nonzero if it is safe for the
delay slot scheduler to place instructions in the delay slot of @var{insn},
even if they appear to set or clobber a resource referenced in @var{insn}.
slot of @var{insn}.
You need not define this macro if it would always return zero.
+@end defmac
-@findex MACHINE_DEPENDENT_REORG
-@item MACHINE_DEPENDENT_REORG (@var{insn})
-In rare cases, correct code generation requires extra machine
-dependent processing between the second jump optimization pass and
-delayed branch scheduling. On those machines, define this macro as a C
-statement to act on the code starting at @var{insn}.
-
-@findex MULTIPLE_SYMBOL_SPACES
-@item MULTIPLE_SYMBOL_SPACES
+@defmac MULTIPLE_SYMBOL_SPACES
Define this macro if in some cases global symbols from one translation
unit may not be bound to undefined symbols in another translation unit
without user intervention. For instance, under Microsoft Windows
symbols must be explicitly imported from shared libraries (DLLs).
+@end defmac
-@findex MD_ASM_CLOBBERS
-@item MD_ASM_CLOBBERS (@var{clobbers})
+@defmac MD_ASM_CLOBBERS (@var{clobbers})
A C statement that adds to @var{clobbers} @code{STRING_CST} trees for
any hard regs the port wishes to automatically clobber for all asms.
+@end defmac
-@findex MAX_INTEGER_COMPUTATION_MODE
-@item MAX_INTEGER_COMPUTATION_MODE
+@defmac MAX_INTEGER_COMPUTATION_MODE
Define this to the largest integer machine mode which can be used for
operations other than load, store and copy operations.
You need only define this macro if the target holds values larger than
@code{word_mode} in general purpose registers. Most targets should not define
this macro.
+@end defmac
-@findex MATH_LIBRARY
-@item MATH_LIBRARY
+@defmac MATH_LIBRARY
Define this macro as a C string constant for the linker argument to link
in the system math library, or @samp{""} if the target does not have a
separate math library.
You need only define this macro if the default of @samp{"-lm"} is wrong.
+@end defmac
-@findex LIBRARY_PATH_ENV
-@item LIBRARY_PATH_ENV
+@defmac LIBRARY_PATH_ENV
Define this macro as a C string constant for the environment variable that
specifies where the linker should look for libraries.
You need only define this macro if the default of @samp{"LIBRARY_PATH"}
is wrong.
+@end defmac
-@findex TARGET_HAS_F_SETLKW
-@item TARGET_HAS_F_SETLKW
+@defmac TARGET_HAS_F_SETLKW
Define this macro if the target supports file locking with fcntl / F_SETLKW@.
Note that this functionality is part of POSIX@.
Defining @code{TARGET_HAS_F_SETLKW} will enable the test coverage code
to use file locking when exiting a program, which avoids race conditions
if the program has forked.
+@end defmac
-@findex MAX_CONDITIONAL_EXECUTE
-@item MAX_CONDITIONAL_EXECUTE
+@defmac MAX_CONDITIONAL_EXECUTE
A C expression for the maximum number of instructions to execute via
conditional execution instructions instead of a branch. A value of
@code{BRANCH_COST}+1 is the default if the machine does not use cc0, and
1 if it does use cc0.
+@end defmac
-@findex IFCVT_MODIFY_TESTS
-@item IFCVT_MODIFY_TESTS(@var{ce_info}, @var{true_expr}, @var{false_expr})
+@defmac IFCVT_MODIFY_TESTS (@var{ce_info}, @var{true_expr}, @var{false_expr})
Used if the target needs to perform machine-dependent modifications on the
conditionals used for turning basic blocks into conditionally executed code.
@var{ce_info} points to a data structure, @code{struct ce_if_block}, which
and @var{false_expr} are the tests that are used for converting the
then-block and the else-block, respectively. Set either @var{true_expr} or
@var{false_expr} to a null pointer if the tests cannot be converted.
+@end defmac
-@findex IFCVT_MODIFY_MULTIPLE_TESTS
-@item IFCVT_MODIFY_MULTIPLE_TESTS(@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr})
+@defmac IFCVT_MODIFY_MULTIPLE_TESTS (@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr})
Like @code{IFCVT_MODIFY_TESTS}, but used when converting more complicated
if-statements into conditions combined by @code{and} and @code{or} operations.
@var{bb} contains the basic block that contains the test that is currently
being processed and about to be turned into a condition.
+@end defmac
-@findex IFCVT_MODIFY_INSN
-@item IFCVT_MODIFY_INSN(@var{ce_info}, @var{pattern}, @var{insn})
+@defmac IFCVT_MODIFY_INSN (@var{ce_info}, @var{pattern}, @var{insn})
A C expression to modify the @var{PATTERN} of an @var{INSN} that is to
be converted to conditional execution format. @var{ce_info} points to
a data structure, @code{struct ce_if_block}, which contains information
about the currently processed blocks.
+@end defmac
-@findex IFCVT_MODIFY_FINAL
-@item IFCVT_MODIFY_FINAL(@var{ce_info})
+@defmac IFCVT_MODIFY_FINAL (@var{ce_info})
A C expression to perform any final machine dependent modifications in
converting code to conditional execution. The involved basic blocks
can be found in the @code{struct ce_if_block} structure that is pointed
to by @var{ce_info}.
+@end defmac
-@findex IFCVT_MODIFY_CANCEL
-@item IFCVT_MODIFY_CANCEL(@var{ce_info})
+@defmac IFCVT_MODIFY_CANCEL (@var{ce_info})
A C expression to cancel any machine dependent modifications in
converting code to conditional execution. The involved basic blocks
can be found in the @code{struct ce_if_block} structure that is pointed
to by @var{ce_info}.
+@end defmac
-@findex IFCVT_INIT_EXTRA_FIELDS
-@item IFCVT_INIT_EXTRA_FIELDS(@var{ce_info})
+@defmac IFCVT_INIT_EXTRA_FIELDS (@var{ce_info})
A C expression to initialize any extra fields in a @code{struct ce_if_block}
structure, which are defined by the @code{IFCVT_EXTRA_FIELDS} macro.
+@end defmac
-@findex IFCVT_EXTRA_FIELDS
-@item IFCVT_EXTRA_FIELDS
+@defmac IFCVT_EXTRA_FIELDS
If defined, it should expand to a set of field declarations that will be
-added to the @code{struct ce_if_block} structure. These should be intialized
+added to the @code{struct ce_if_block} structure. These should be initialized
by the @code{IFCVT_INIT_EXTRA_FIELDS} macro.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_MACHINE_DEPENDENT_REORG ()
+If non-null, this hook performs a target-specific pass over the
+instruction stream. The compiler will run it at all optimization levels,
+just before the point at which it normally does delayed-branch scheduling.
-@end table
+The exact purpose of the hook varies from target to target. Some use
+it to do transformations that are necessary for correctness, such as
+laying out in-function constant pools or avoiding hardware hazards.
+Others use it as an opportunity to do some machine-dependent optimizations.
+
+You need not implement the hook if it has nothing to do. The default
+definition is null.
+@end deftypefn
@deftypefn {Target Hook} void TARGET_INIT_BUILTINS ()
Define this hook if you have any machine-specific built-in functions
built-in function.
@end deftypefn
-@table @code
-@findex MD_CAN_REDIRECT_BRANCH
-@item MD_CAN_REDIRECT_BRANCH(@var{branch1}, @var{branch2})
+@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
Take a branch insn in @var{branch1} and another in @var{branch2}.
Return true if redirecting @var{branch1} to the destination of
On some targets, branches may have a limited range. Optimizing the
filling of delay slots can result in branches being redirected, and this
may in turn cause a branch offset to overflow.
+@end defmac
-@findex ALLOCATE_INITIAL_VALUE
-@item ALLOCATE_INITIAL_VALUE(@var{hard_reg})
+@defmac ALLOCATE_INITIAL_VALUE (@var{hard_reg})
When the initial value of a hard register has been copied in a pseudo
register, it is often not necessary to actually allocate another register
You may use @code{current_function_leaf_function} in the definition of the
macro, functions that use @code{REG_N_SETS}, to determine if the hard
register in question will not be clobbered.
+@end defmac
-@findex TARGET_OBJECT_SUFFIX
-@item TARGET_OBJECT_SUFFIX
+@defmac TARGET_OBJECT_SUFFIX
Define this macro to be a C string representing the suffix for object
files on your target machine. If you do not define this macro, GCC will
use @samp{.o} as the suffix for object files.
+@end defmac
-@findex TARGET_EXECUTABLE_SUFFIX
-@item TARGET_EXECUTABLE_SUFFIX
+@defmac TARGET_EXECUTABLE_SUFFIX
Define this macro to be a C string representing the suffix to be
automatically added to executable files on your target machine. If you
do not define this macro, GCC will use the null string as the suffix for
executable files.
+@end defmac
-@findex COLLECT_EXPORT_LIST
-@item COLLECT_EXPORT_LIST
+@defmac COLLECT_EXPORT_LIST
If defined, @code{collect2} will scan the individual object files
specified on its command line and create an export list for the linker.
Define this macro for systems like AIX, where the linker discards
object files that are not referenced from @code{main} and uses export
lists.
+@end defmac
+
+@defmac MODIFY_JNI_METHOD_CALL (@var{mdecl})
+Define this macro to a C expression representing a variant of the
+method call @var{mdecl}, if Java Native Interface (JNI) methods
+must be invoked differently from other methods on your target.
+For example, on 32-bit Windows, JNI methods must be invoked using
+the @code{stdcall} calling convention and this macro is then
+defined as this expression:
-@end table
+@smallexample
+build_type_attribute_variant (@var{mdecl},
+ build_tree_list
+ (get_identifier ("stdcall"),
+ NULL))
+@end smallexample
+@end defmac
@deftypefn {Target Hook} bool TARGET_CANNOT_MODIFY_JUMPS_P (void)
This target hook returns @code{true} past the point in which new jump
@}
@end smallexample
@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_BRANCH_TARGET_REGISTER_CLASS (void)
+This target hook returns a register class for which branch target register
+optimizations should be applied. All registers in this class should be
+usable interchangeably. After reload, registers in this class will be
+re-allocated and loads will be hoisted out of loops and be subjected
+to inter-block scheduling.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED (bool @var{after_prologue_epilogue_gen})
+Branch target register optimization will by default exclude callee-saved
+registers
+that are not already live during the current function; if this target hook
+returns true, they will be included. The target code must than make sure
+that all target registers in the class returned by
+@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are
+saved. @var{after_prologue_epilogue_gen} indicates if prologues and
+epilogues have already been generated. Note, even if you only return
+true when @var{after_prologue_epilogue_gen} is false, you still are likely
+to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}
+to reserve space for caller-saved target registers.
+@end deftypefn
+
+@defmac POWI_MAX_MULTS
+If defined, this macro is interpreted as a signed integer C expression
+that specifies the maximum number of floating point multiplications
+that should be emitted when expanding exponentiation by an integer
+constant inline. When this value is defined, exponentiation requiring
+more than this number of multiplications is implemented by calling the
+system library's @code{pow}, @code{powf} or @code{powl} routines.
+The default value places no upper bound on the multiplication count.
+@end defmac
+
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