@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
-@c 2002, 2003, 2004 Free Software Foundation, Inc.
+@c 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
* Per-Function Data:: Defining data structures for per-function information.
* Storage Layout:: Defining sizes and alignments of data.
* Type Layout:: Defining sizes and properties of basic user data types.
-* Escape Sequences:: Defining the value of target character escape sequences
* Registers:: Naming and describing the hardware registers.
* Register Classes:: Defining the classes of hardware registers.
* Stack and Calling:: Defining which way the stack grows and by how much.
@end smallexample
@end defmac
-@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
-
@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
@defmac LINK_GCC_C_SEQUENCE_SPEC
@end defmac
@deftypevar {extern int} target_flags
-This declaration should be present.
+This variable is declared in @file{options.h}, which is included before
+any target-specific headers.
@end deftypevar
+@deftypevar {Target Hook} int TARGET_DEFAULT_TARGET_FLAGS
+This variable specifies the initial value of @code{target_flags}.
+Its default setting is 0.
+
+If the target defines @code{TARGET_SWITCHES}, the null
+@code{TARGET_SWITCHES} entry will override this value.
+@end deftypevar
+
+@deftypefn {Target Hook} bool TARGET_HANDLE_OPTION (size_t @var{code}, const char *@var{arg}, int @var{value})
+This hook is called whenever the user specifies one of the
+target-specific options described by the @file{.opt} definition files
+(@pxref{Options}). It has the opportunity to do some option-specific
+processing and should return true if the option is valid. The default
+definition does nothing but return true.
+
+@var{code} specifies the @code{OPT_@var{name}} enumeration value
+associated with the selected option; @var{name} is just a rendering of
+the option name in which non-alphanumeric characters are replaced by
+underscores. @var{arg} specifies the string argument and is null if
+no argument was given. If the option is flagged as a @code{UInteger}
+(@pxref{Option properties}), @var{value} is the numeric value of the
+argument. Otherwise @var{value} is 1 if the positive form of the
+option was used and 0 if the ``no-'' form was.
+@end deftypefn
+
@cindex optional hardware or system features
@cindex features, optional, in system conventions
@{ "", MASK_68020, "" @}, \
@}
@end smallexample
+
+This macro is being kept for compatibility with older backends.
+New targets should use option definition files instead.
+@xref{Back End}.
@end defmac
@defmac TARGET_OPTIONS
@smallexample
[chip.c]
-char *chip_alu = ""; /* Specify default here. */
+char *chip_alu = ""; /* @r{Specify default here.} */
[chip.h]
extern char *chip_alu;
#define TARGET_ALU1 (chip_alu[0] == '1')
#define TARGET_ALU2 (chip_alu[0] == '2')
@end smallexample
+
+This macro is being kept for compatibility with older backends.
+New targets should use option definition files instead.
+@xref{Back End}.
@end defmac
@defmac TARGET_VERSION
words.
@end defmac
+@defmac LIBGCC2_LONG_DOUBLE_TYPE_SIZE
+Define this macro if @code{LONG_DOUBLE_TYPE_SIZE} is not constant or
+if you want routines in @file{libgcc2.a} for a size other than
+@code{LONG_DOUBLE_TYPE_SIZE}. If you don't define this, the
+default is @code{LONG_DOUBLE_TYPE_SIZE}.
+@end defmac
+
+@defmac LIBGCC2_HAS_DF_MODE
+Define this macro if neither @code{LIBGCC2_DOUBLE_TYPE_SIZE} nor
+@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is
+@code{DFmode} but you want @code{DFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and either @code{LIBGCC2_DOUBLE_TYPE_SIZE}
+or @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64 then the default is 1,
+otherwise it is 0.
+@end defmac
+
+@defmac LIBGCC2_HAS_XF_MODE
+Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not
+@code{XFmode} but you want @code{XFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE}
+is 80 then the default is 1, otherwise it is 0.
+@end defmac
+
+@defmac LIBGCC2_HAS_TF_MODE
+Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not
+@code{TFmode} but you want @code{TFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE}
+is 128 then the default is 1, otherwise it is 0.
+@end defmac
+
@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
of words in each data entry.
@end defmac
-@node Escape Sequences
-@section Target Character Escape Sequences
-@cindex escape sequences
-
-By default, GCC assumes that the C character escape sequences and other
-characters take on their ASCII values for the target. If this is not
-correct, you must explicitly define all of the macros below. All of
-them must evaluate to constants; they are used in @code{case}
-statements.
-
-@findex TARGET_BELL
-@findex TARGET_BS
-@findex TARGET_CR
-@findex TARGET_DIGIT0
-@findex TARGET_ESC
-@findex TARGET_FF
-@findex TARGET_NEWLINE
-@findex TARGET_TAB
-@findex TARGET_VT
-@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_BS} @tab @kbd{\b} @tab @code{08}, @code{BS}
-@item @code{TARGET_CR} @tab @kbd{\r} @tab @code{0D}, @code{CR}
-@item @code{TARGET_DIGIT0} @tab @kbd{0} @tab @code{30}, @code{ZERO}
-@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
@cindex register usage
these registers when the target switches are opposed to them.)
@end defmac
-@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
-
@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
machines. See @file{function.c} for details.
@end defmac
+@defmac INITIAL_FRAME_ADDRESS_RTX
+A C expression whose value is RTL representing the address of the initial
+ stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
+@code{DYNAMIC_CHAIN_ADDRESS}.
+If you don't define this macro, the default is to return
+@code{hard_frame_pointer_rtx}.
+This default is usually correct unless @code{-fomit-frame-pointer} is in
+effect.
+Define this macro in order to make @code{__builtin_frame_address (0)} and
+@code{__builtin_return_address (0)} work even in absence of a hard frame pointer.
+@end defmac
+
@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
terminate the stack backtrace. New ports should avoid this.
@end defmac
+@deftypefn {Target Hook} void TARGET_DWARF_HANDLE_FRAME_UNSPEC (const char *@var{label}, rtx @var{pattern}, int @var{index})
+This target hook allows the backend to emit frame-related insns that
+contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging
+info engine will invoke it on insns of the form
+@smallexample
+(set (reg) (unspec [...] UNSPEC_INDEX))
+@end smallexample
+and
+@smallexample
+(set (reg) (unspec_volatile [...] UNSPECV_INDEX)).
+@end smallexample
+to let the backend emit the call frame instructions. @var{label} is
+the CFI label attached to the insn, @var{pattern} is the pattern of
+the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.
+@end deftypefn
+
@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
serves both purposes.
@end defmac
-@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
+@deftypefn {Target Hook} int TARGET_ARG_PARTIAL_BYTES (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named})
+This target hook returns the number of bytes 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
pushed on the stack.
On some machines, certain arguments must be passed partially in
registers and partially in memory. On these machines, typically the
-first @var{n} words of arguments are passed in registers, and the rest
+first few words of arguments are passed in registers, and the rest
on the stack. If a multi-word argument (a @code{double} or a
structure) crosses that boundary, its first few words must be passed
in registers and the rest must be pushed. This macro tells the
-compiler when this occurs, and how many of the words should go in
-registers.
+compiler when this occurs, and how many bytes should go in registers.
@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
+@end deftypefn
@deftypefn {Target Hook} bool TARGET_PASS_BY_REFERENCE (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named})
This target hook should return @code{true} if an argument at the
false.
@end deftypefn
+@deftypefn {Target Hook} tree TARGET_BUILD_BUILTIN_VA_LIST (void)
+This hook returns a type node for @code{va_list} for the target.
+The default version of the hook returns @code{void*}.
+@end deftypefn
+
@deftypefn {Target Hook} tree TARGET_GIMPLIFY_VA_ARG_EXPR (tree @var{valist}, tree @var{type}, tree *@var{pre_p}, tree *@var{post_p})
This hook performs target-specific gimplification of
@code{VA_ARG_EXPR}. The first two parameters correspond to the
@code{gimplify.c:gimplify_expr}.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_VALID_POINTER_MODE (enum machine_mode @var{mode})
+Define this to return nonzero if the port can handle pointers
+with machine mode @var{mode}. The default version of this
+hook returns true for both @code{ptr_mode} and @code{Pmode}.
+@end deftypefn
+
@deftypefn {Target Hook} bool TARGET_SCALAR_MODE_SUPPORTED_P (enum machine_mode @var{mode})
Define this to return nonzero if the port is prepared to handle
insns involving scalar mode @var{mode}. For a scalar mode to be
@c tell? --mew 5feb93
@end deftypefn
-@deftypefn {Target Hook} bool TARGET_LATE_RTL_PROLOGUE_EPILOGUE
-If set to @code{true}, it instructs the compiler to emit the RTL prologue
-and epilogue later in the game than usual, namely after all passes that
-modify the instructions (and not merely reorder them) have been run. In
-particular, the C variable @code{current_function_uses_only_leaf_regs} is
-valid at that point. This can be used on machines that have "register
-windows" to optimize away the regular "push" on the register stack.
-@xref{Leaf Functions}.
-@end deftypefn
-
@itemize @bullet
@item
@findex current_function_pretend_args_size
anything @code{CONSTANT_P} is valid.
@end defmac
+@deftypefn {Target Hook} rtx TARGET_DELEGITIMIZE_ADDRESS (rtx @var{x})
+This hook is used to undo the possibly obfuscating effects of the
+@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target
+macros. Some backend implementations of these macros wrap symbol
+references inside an @code{UNSPEC} rtx to represent PIC or similar
+addressing modes. This target hook allows GCC's optimizers to understand
+the semantics of these opaque @code{UNSPEC}s by converting them back
+into their original form.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CANNOT_FORCE_CONST_MEM (rtx @var{x})
+This hook should return true if @var{x} is of a form that cannot (or
+should not) be spilled to the constant pool. The default version of
+this hook returns false.
+
+The primary reason to define this hook is to prevent reload from
+deciding that a non-legitimate constant would be better reloaded
+from the constant pool instead of spilling and reloading a register
+holding the constant. This restriction is often true of addresses
+of TLS symbols for various targets.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void)
+This hook should return the DECL of a function @var{f} that given an
+address @var{addr} as an argument returns a mask @var{m} that can be
+used to extract from two vectors the relevant data that resides in
+@var{addr} in case @var{addr} is not properly aligned.
+
+The autovectrizer, when vectorizing a load operation from an address
+@var{addr} that may be unaligned, will generate two vector loads from
+the two aligned addresses around @var{addr}. It then generates a
+@code{REALIGN_LOAD} operation to extract the relevant data from the
+two loaded vectors. The first two arguments to @code{REALIGN_LOAD},
+@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and
+the third argument, @var{OFF}, defines how the data will be extracted
+from these two vectors: if @var{OFF} is 0, then the returned vector is
+@var{v2}; otherwise, the returned vector is composed from the last
+@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first
+@var{OFF} elements of @var{v2}.
+
+If this hook is defined, the autovectorizer will generate a call
+to @var{f} (using the DECL tree that this hook returns) and will
+use the return value of @var{f} as the argument @var{OFF} to
+@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}
+should comply with the semantics expected by @code{REALIGN_LOAD}
+described above.
+If this hook is not defined, then @var{addr} will be used as
+the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low
+log2(@var{VS})-1 bits of @var{addr} will be considered.
+@end deftypefn
+
@node Condition Code
@section Condition Code Status
@cindex condition code status
definition of this macro is provided which is correct for most systems.
@end defmac
+@findex assemble_name_raw
+@defmac ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{name})
+Identical to @code{ASM_OUTPUT_lABEL}, except that @var{name} is known
+to refer to a compiler-generated label. The default definition uses
+@code{assemble_name_raw}, which is like @code{assemble_name} except
+that it is more efficient.
+@end defmac
+
@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
correct for most systems.
@end defmac
+@defmac TARGET_DEFERRED_OUTPUT_DEFS (@var{decl_of_name}, @var{decl_of_value})
+A C statement that evaluates to true if the 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} should be emitted near the end of the
+current compilation unit. The default is to not defer output of defines.
+This macro affects defines output by @samp{ASM_OUTPUT_DEF} and
+@samp{ASM_OUTPUT_DEF_FROM_DECLS}.
+@end defmac
+
@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
also defined.
@end defmac
+@defmac EH_TABLES_CAN_BE_READ_ONLY
+Define this macro to 1 if your target is such that no frame unwind
+information encoding used with non-PIC code will ever require a
+runtime relocation, but the linker may not support merging read-only
+and read-write sections into a single read-write section.
+@end defmac
+
@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.
is in effect.
@end defmac
-@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
-
@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.
@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{c_register_pragma} for each pragma. The macro may also do any
+@code{c_register_pragma} or @code{c_register_pragma_with_expansion}
+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
@end defmac
@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
+@deftypefunx void c_register_pragma_with_expansion (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-Each call to @code{c_register_pragma} establishes one pragma. The
+Each call to @code{c_register_pragma} or
+@code{c_register_pragma_with_expansion} 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}. Macro expansion occurs on the
+arguments of pragmas registered with
+@code{c_register_pragma_with_expansion} but not on the arguments of
+pragmas registered with @code{c_register_pragma}.
For an example use of this routine, see @file{c4x.h} and the callback
routines defined in @file{c4x-c.c}.
value.
@end defmac
+@defmac HANDLE_PRAGMA_PACK_WITH_EXPANSION
+Define this macro, as well as
+@code{HANDLE_SYSV_PRAGMA}, if macros should be expanded in the
+arguments of @samp{#pragma pack}.
+@end defmac
+
@defmac TARGET_DEFAULT_PACK_STRUCT
If your target requires a structure packing default other than 0 (meaning
the machine default), define this macro the the necessary value (in bytes).
built-in function.
@end deftypefn
+@deftypefn {Target Hook} tree TARGET_FOLD_BUILTIN (tree @var{exp}, bool @var{ignore})
+
+Expand a call to a machine specific built-in function that was set up by
+@samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the
+function call; the result is another tree containing a simplified
+expression for the call's result. If @var{ignore} is true the
+value will be ignored.
+@end deftypefn
+
@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
Take a branch insn in @var{branch1} and another in @var{branch2}.
If defined, this macro is the number of entries in
@code{TARGET_FORMAT_TYPES}.
@end defmac
+
+@deftypefn {Target Hook} bool TARGET_RELAXED_ORDERING
+If set to @code{true}, means that the target's memory model does not
+guarantee that loads which do not depend on one another will access
+main memory in the order of the instruction stream; if ordering is
+important, an explicit memory barrier must be used. This is true of
+many recent processors which implement a policy of ``relaxed,''
+``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,
+and ia64. The default is @code{false}.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN (tree @var{typelist}, tree @var{funcdecl}, tree @var{val})
+If defined, this macro returns the diagnostic message when it is
+illegal to pass argument @var{val} to function @var{funcdecl}
+with prototype @var{typelist}.
+@end deftypefn
+
+@defmac TARGET_USE_JCR_SECTION
+This macro determines whether to use the JCR section to register Java
+classes. By default, TARGET_USE_JCR_SECTION is defined to 1 if both
+SUPPORTS_WEAK and TARGET_HAVE_NAMED_SECTIONS are true, else 0.
+@end defmac
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