@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.
@end deftypevar
@cindex optional hardware or system features
@cindex features, optional, in system conventions
-@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
-the 68020; a command argument tells the compiler whether it should
-use 68020-only instructions or not. This command argument works
-by means of a macro @code{TARGET_68020} that tests a bit in
-@code{target_flags}.
-
-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{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 & MASK_68020)
-@end smallexample
-
-One place where these macros are used is in the condition-expressions
-of instruction patterns. Note how @code{TARGET_68020} appears
-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
-
-@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.
-
-Each subgrouping contains a string constant, that defines the option
-name, a number, which contains the bits to set in
-@code{target_flags}, and a second string which is the description
-displayed by @option{--help}. If the number is negative then the bits specified
-by the number are cleared instead of being set. If the description
-string is present but empty, then no help information will be displayed
-for that option, but it will not count as an undocumented option. The
-actual option name is made by appending @samp{-m} to the specified name.
-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.
-
-In addition to the description for @option{--help},
-more detailed documentation for each option should be added to
-@file{invoke.texi}.
-
-One of the subgroupings should have a null string. The number in
-this grouping is the default value for @code{target_flags}. Any
-target options act starting with that value.
-
-Here is an example which defines @option{-m68000} and @option{-m68020}
-with opposite meanings, and picks the latter as the default:
-
-@smallexample
-#define TARGET_SWITCHES \
- @{ @{ "68020", MASK_68020, "" @}, \
- @{ "68000", -MASK_68020, \
- N_("Compile for the 68000") @}, \
- @{ "", MASK_68020, "" @}, \
- @}
-@end smallexample
-@end defmac
-
-@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 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}.
-
-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}
-will be set to the string @code{"512"}.
-
-@smallexample
-extern char *m88k_short_data;
-#define TARGET_OPTIONS \
- @{ @{ "short-data-", &m88k_short_data, \
- 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
-
-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
+@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
@defmac TARGET_VERSION
This macro is a C statement to print on @code{stderr} a string
@end defmac
@defmac UNITS_PER_WORD
-Number of storage units in a word; normally 4.
+Number of storage units in a word; normally the size of a general-purpose
+register, a power of two from 1 or 8.
@end defmac
@defmac MIN_UNITS_PER_WORD
smallest value that @code{UNITS_PER_WORD} can have at run-time.
@end defmac
+@defmac UNITS_PER_SIMD_WORD
+Number of units in the vectors that the vectorizer can produce.
+The default is equal to @code{UNITS_PER_WORD}, because the vectorizer
+can do some transformations even in absence of specialized @acronym{SIMD}
+hardware.
+@end defmac
+
@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},
@code{STACK_BOUNDARY}.
@end defmac
-@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}.
-
-@cindex @code{PUSH_ROUNDING}, interaction with @code{PREFERRED_STACK_BOUNDARY}
-If @code{PUSH_ROUNDING} is not defined, the stack will always be aligned
-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
-
@defmac FUNCTION_BOUNDARY
Alignment required for a function entry point, in bits.
@end defmac
may affect its placement.
@end deftypefn
+@deftypefn {Target Hook} {bool} TARGET_DECIMAL_FLOAT_SUPPORTED_P (void)
+Returns true if the target supports decimal floating point.
+@end deftypefn
+
@deftypefn {Target Hook} {const char *} TARGET_MANGLE_FUNDAMENTAL_TYPE (tree @var{type})
If your target defines any fundamental types, define this hook to
return the appropriate encoding for these types as part of a C++
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 SF_SIZE
+@defmacx DF_SIZE
+@defmacx XF_SIZE
+@defmacx TF_SIZE
+Define these macros to be the size in bits of the mantissa of
+@code{SFmode}, @code{DFmode}, @code{XFmode} and @code{TFmode} values,
+if the defaults in @file{libgcc2.h} are inappropriate. By default,
+@code{FLT_MANT_DIG} is used for @code{SF_SIZE}, @code{LDBL_MANT_DIG}
+for @code{XF_SIZE} and @code{TF_SIZE}, and @code{DBL_MANT_DIG} or
+@code{LDBL_MANT_DIG} for @code{DF_SIZE} according to whether
+@code{LIBGCC2_DOUBLE_TYPE_SIZE} or
+@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64.
+@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
require the macro to do something nontrivial.
@end defmac
-@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})
+@deftypefn {Target Hook} enum reg_class TARGET_SECONDARY_RELOAD (bool @var{in_p}, rtx @var{x}, enum reg_class @var{reload_class}, enum machine_mode @var{reload_mode}, secondary_reload_info *@var{sri})
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
-from general registers, but not memory. Some machines allow copying all
-registers to and from memory, but require a scratch register for stores
-to some memory locations (e.g., those with symbolic address on the RT,
-and those with certain symbolic address on the SPARC when compiling
-PIC)@. In some cases, both an intermediate and a scratch register are
-required.
+from general registers, but not memory. Below, we shall be using the
+term 'intermediate register' when a move operation cannot be performed
+directly, but has to be done by copying the source into the intermediate
+register first, and then copying the intermediate register to the
+destination. An intermediate register always has the same mode as
+source and destination. Since it holds the actual value being copied,
+reload might apply optimizations to re-use an intermediate register
+and eliding the copy from the source when it can determine that the
+intermediate register still holds the required value.
+
+Another kind of secondary reload is required on some machines which
+allow copying all registers to and from memory, but require a scratch
+register for stores to some memory locations (e.g., those with symbolic
+address on the RT, and those with certain symbolic address on the SPARC
+when compiling PIC)@. Scratch registers need not have the same mode
+as the value being copied, and usually hold a different value that
+that being copied. Special patterns in the md file are needed to
+describe how the copy is performed with the help of the scratch register;
+these patterns also describe the number, register class(es) and mode(s)
+of the scratch register(s).
+
+In some cases, both an intermediate and a scratch register are required.
+
+For input reloads, this target hook is called with nonzero @var{in_p},
+and @var{x} is an rtx that needs to be copied to a register in of class
+@var{reload_class} in @var{reload_mode}. For output reloads, this target
+hook is called with zero @var{in_p}, and a register of class @var{reload_mode}
+needs to be copied to rtx @var{x} in @var{reload_mode}.
+
+If copying a register of @var{reload_class} from/to @var{x} requires
+an intermediate register, the hook @code{secondary_reload} should
+return the register class required for this intermediate register.
+If no intermediate register is required, it should return NO_REGS.
+If more than one intermediate register is required, describe the one
+that is closest in the copy chain to the reload register.
+
+If scratch registers are needed, you also have to describe how to
+perform the copy from/to the reload register to/from this
+closest intermediate register. Or if no intermediate register is
+required, but still a scratch register is needed, describe the
+copy from/to the reload register to/from the reload operand @var{x}.
+
+You do this by setting @code{sri->icode} to the instruction code of a pattern
+in the md file which performs the move. Operands 0 and 1 are the output
+and input of this copy, respectively. Operands from operand 2 onward are
+for scratch operands. These scratch operands must have a mode, and a
+single-register-class
+@c [later: or memory]
+output constraint.
+
+When an intermediate register is used, the @code{secondary_reload}
+hook will be called again to determine how to copy the intermediate
+register to/from the reload operand @var{x}, so your hook must also
+have code to handle the register class of the intermediate operand.
+
+@c [For later: maybe we'll allow multi-alternative reload patterns -
+@c the port maintainer could name a mov<mode> pattern that has clobbers -
+@c and match the constraints of input and output to determine the required
+@c alternative. A restriction would be that constraints used to match
+@c against reloads registers would have to be written as register class
+@c constraints, or we need a new target macro / hook that tells us if an
+@c arbitrary constraint can match an unknown register of a given class.
+@c Such a macro / hook would also be useful in other places.]
-You should define these macros to indicate to the reload phase that it may
+
+@var{x} might be a pseudo-register or a @code{subreg} of a
+pseudo-register, which could either be in a hard register or in memory.
+Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is
+in memory and the hard register number if it is in a register.
+
+Scratch operands in memory (constraint @code{"=m"} / @code{"=&m"}) are
+currently not supported. For the time being, you will have to continue
+to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.
+
+@code{copy_cost} also uses this target hook to find out how values are
+copied. If you want it to include some extra cost for the need to allocate
+(a) scratch register(s), set @code{sri->extra_cost} to the additional cost.
+Or if two dependent moves are supposed to have a lower cost than the sum
+of the individual moves due to expected fortuitous scheduling and/or special
+forwarding logic, you can set @code{sri->extra_cost} to a negative amount.
+@end deftypefn
+
+@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})
+These macros are obsolete, new ports should use the target hook
+@code{TARGET_SECONDARY_RELOAD} instead.
+
+These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD}
+target hook. Older ports still define these macros to indicate to the
+reload phase that it may
need to allocate at least one register for a reload in addition to the
register to contain the data. Specifically, if copying @var{x} to a
register @var{class} in @var{mode} requires an intermediate register,
-you should define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
+you were supposed to define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
largest register class all of whose registers can be used as
intermediate registers or scratch registers.
If copying a register @var{class} in @var{mode} to @var{x} requires an
intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS}
-should be defined to return the largest register class required. If the
-requirements for input and output reloads are the same, the macro
-@code{SECONDARY_RELOAD_CLASS} should be used instead of defining both
+was supposed to be defined be defined to return the largest register
+class required. If the
+requirements for input and output reloads were the same, the macro
+@code{SECONDARY_RELOAD_CLASS} should have been used instead of defining both
macros identically.
The values returned by these macros are often @code{GENERAL_REGS}.
macro if it would always return @code{NO_REGS}.
If a scratch register is required (either with or without an
-intermediate register), you should define patterns for
+intermediate register), you were supposed to define patterns for
@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required
-(@pxref{Standard Names}. These patterns, which will normally be
+(@pxref{Standard Names}. These patterns, which were normally
implemented with a @code{define_expand}, should be similar to the
@samp{mov@var{m}} patterns, except that operand 2 is the scratch
register.
-Define constraints for the reload register and scratch register that
+These patterns need constraints for the reload register and scratch
+register that
contain a single register class. If the original reload register (whose
class is @var{class}) can meet the constraint given in the pattern, the
value returned by these macros is used for the class of the scratch
* Function Entry::
* Profiling::
* Tail Calls::
+* Stack Smashing Protection::
@end menu
@node Frame Layout
@end defmac
@defmac FRAME_GROWS_DOWNWARD
-Define this macro if the addresses of local variable slots are at negative
-offsets from the frame pointer.
+Define this macro to nonzero value if the addresses of local variable slots
+are at negative offsets from the frame pointer.
@end defmac
@defmac ARGS_GROW_DOWNWARD
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, a reasonable
+default value will be used. Define this macro in order to make frame pointer
+elimination work in the presence of @code{__builtin_frame_address (count)} and
+@code{__builtin_return_address (count)} for @code{count} not equal to zero.
+@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
DWARF 2.
@end defmac
+@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl})
+If defined, a C expression whose value is an integer giving the offset
+in bytes from the frame pointer to the canonical frame address (cfa).
+The final value should conincide with that calculated by
+@code{INCOMING_FRAME_SP_OFFSET}.
+
+Normally the CFA is calculated as an offset from the argument pointer,
+via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
+variable due to the ABI, this may not be possible. If this macro is
+defined, it implies that the virtual register instantiation should be
+based on the frame pointer instead of the argument pointer. Only one
+of @code{FRAME_POINTER_CFA_OFFSET} and @code{ARG_POINTER_CFA_OFFSET}
+should be defined.
+@end defmac
+
@node Exception Handling
@subsection Exception Handling Support
@cindex exception handling
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
may vary greatly between different architectures.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap *@var{regs})
+Add any hard registers to @var{regs} that are live on entry to the
+function. This hook only needs to be defined to provide registers that
+cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved
+registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,
+TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,
+FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.
+@end deftypefn
+
+@node Stack Smashing Protection
+@subsection Stack smashing protection
+@cindex stack smashing protection
+
+@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_GUARD (void)
+This hook returns a @code{DECL} node for the external variable to use
+for the stack protection guard. This variable is initialized by the
+runtime to some random value and is used to initialize the guard value
+that is placed at the top of the local stack frame. The type of this
+variable must be @code{ptr_type_node}.
+
+The default version of this hook creates a variable called
+@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_FAIL (void)
+This hook returns a tree expression that alerts the runtime that the
+stack protect guard variable has been modified. This expression should
+involve a call to a @code{noreturn} function.
+
+The default version of this hook invokes a function called
+@samp{__stack_chk_fail}, taking no arguments. This function is
+normally defined in @file{libgcc2.c}.
+@end deftypefn
+
@node Varargs
@section Implementing the Varargs Macros
@cindex varargs implementation
@end defmac
@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.
+Return the section into which the trampoline template is to be placed
+(@pxref{Sections}). The default value is @code{readonly_data_section}.
@end defmac
@defmac TRAMPOLINE_SIZE
functions (like @code{__cmpdi2}) return 0 to indicate that the first
operand is smaller than the second, 1 to indicate that they are equal,
and 2 to indicate that the first operand is greater than the second.
-If this macro evalutes to @code{false} the comparison functions return
+If this macro evaluates to @code{false} the comparison functions return
@minus{}1, 0, and 1 instead of 0, 1, and 2. If the target uses the routines
in @file{libgcc.a}, you do not need to define this macro.
@end defmac
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
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 to 1 if @code{move_by_pieces_ninsns} returns less
+Defaults to 1 if @code{move_by_pieces_ninsns} returns less
than @code{MOVE_RATIO}.
@end defmac
This value must be constant over the entire compilation. If you need
it to vary depending on what the instructions are, you must use
@samp{TARGET_SCHED_VARIABLE_ISSUE}.
-
-You could define this hook to return the value of the macro
-@code{MAX_DFA_ISSUE_RATE}.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
not in cases of "costly dependences", which this hooks allows to define.
@end deftypefn
-Macros in the following table are generated by the program
-@file{genattr} and can be useful for writing the hooks.
-
-@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 defmac
-
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
@c the above section title is WAY too long. maybe cut the part between
section}, which holds uninitialized data. Some systems have other kinds
of sections.
-The compiler must tell the assembler when to switch sections. These
-macros control what commands to output to tell the assembler this. You
-can also define additional sections.
+@file{varasm.c} provides several well-known sections, such as
+@code{text_section}, @code{data_section} and @code{bss_section}.
+The normal way of controlling a @code{@var{foo}_section} variable
+is to define the associated @code{@var{FOO}_SECTION_ASM_OP} macro,
+as described below. The macros are only read once, when @file{varasm.c}
+initializes itself, so their values must be run-time constants.
+They may however depend on command-line flags.
+
+@emph{Note:} Some run-time files, such @file{crtstuff.c}, also make
+use of the @code{@var{FOO}_SECTION_ASM_OP} macros, and expect them
+to be string literals.
+
+Some assemblers require a different string to be written every time a
+section is selected. If your assembler falls into this category, you
+should define the @code{TARGET_ASM_INIT_SECTIONS} hook and use
+@code{get_unnamed_section} to set up the sections.
+
+You must always create a @code{text_section}, either by defining
+@code{TEXT_SECTION_ASM_OP} or by initializing @code{text_section}
+in @code{TARGET_ASM_INIT_SECTIONS}. The same is true of
+@code{data_section} and @code{DATA_SECTION_ASM_OP}. If you do not
+create a distinct @code{readonly_data_section}, the default is to
+reuse @code{text_section}.
+
+All the other @file{varasm.c} sections are optional, and are null
+if the target does not provide them.
@defmac TEXT_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
data. Normally @code{"\t.data"} is right.
@end defmac
+@defmac SDATA_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
+initialized, writable small data.
+@end defmac
+
@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
-@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
-
@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
used.
@end defmac
+@defmac SBSS_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, writable small data.
+@end defmac
+
@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.
+not exist. This section has no corresponding @code{init_section}
+variable; it is used entirely in runtime code.
@end defmac
@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.
+not exist. This section has no corresponding @code{fini_section}
+variable; it is used entirely in runtime code.
+@end defmac
+
+@defmac INIT_ARRAY_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
+part of the @code{.init_array} (or equivalent) section. If not
+defined, GCC will assume such a section does not exist. Do not define
+both this macro and @code{INIT_SECTION_ASM_OP}.
+@end defmac
+
+@defmac FINI_ARRAY_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
+part of the @code{.fini_array} (or equivalent) section. If not
+defined, GCC will assume such a section does not exist. Do not define
+both this macro and @code{FINI_SECTION_ASM_OP}.
@end defmac
@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
and thus prevent the linker from having to add any padding.
@end defmac
-@findex in_text
-@findex in_data
-@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 text_section
-@findex data_section
-@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
-
@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
This macro is irrelevant if there is no separate readonly data section.
@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
+@deftypefn {Target Hook} void TARGET_ASM_INIT_SECTIONS (void)
+Define this hook if you need to do something special to set up the
+@file{varasm.c} sections, or if your target has some special sections
+of its own that you need to create.
+
+GCC calls this hook after processing the command line, but before writing
+any assembly code, and before calling any of the section-returning hooks
+described below.
+@end deftypefn
+
+@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align})
+Return the section into which @var{exp} should be placed. You can
assume that @var{exp} is either a @code{VAR_DECL} node or a constant of
some sort. @var{reloc} indicates whether the initial value of @var{exp}
requires link-time relocations. Bit 0 is set when variable contains
local relocations only, while bit 1 is set for global relocations.
-Select the section by calling @code{data_section} or one of the
-alternatives for other sections. @var{align} is the constant alignment
-in bits.
+@var{align} is the constant alignment in bits.
The default version of this function takes care of putting read-only
variables in @code{readonly_data_section}.
Whatever the actual target object format, this is often good enough.
@end deftypefn
-@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_RODATA_SECTION (tree @var{decl})
-Switches to a readonly data section associated with
+@deftypefn {Target Hook} {section *} TARGET_ASM_FUNCTION_RODATA_SECTION (tree @var{decl})
+Return the readonly data section associated with
@samp{DECL_SECTION_NAME (@var{decl})}.
-The default version of this function switches to @code{.gnu.linkonce.r.name}
-section if function's section is @code{.gnu.linkonce.t.name}, to
-@code{.rodata.name} if function is in @code{.text.name} section
-and otherwise switches to the normal readonly data section.
+The default version of this function selects @code{.gnu.linkonce.r.name} if
+the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}
+if function is in @code{.text.name}, and the normal readonly-data section
+otherwise.
@end deftypefn
-@deftypefn {Target Hook} void TARGET_ASM_SELECT_RTX_SECTION (enum machine_mode @var{mode}, rtx @var{x}, unsigned HOST_WIDE_INT @var{align})
-Switches to the appropriate section for output of constant pool entry
-@var{x} in @var{mode}. You can assume that @var{x} is some kind of
+@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_RTX_SECTION (enum machine_mode @var{mode}, rtx @var{x}, unsigned HOST_WIDE_INT @var{align})
+Return the section into which a constant @var{x}, of mode @var{mode},
+should be placed. You can assume that @var{x} is some kind of
constant in RTL@. The argument @var{mode} is redundant except in the
-case of a @code{const_int} rtx. Select the section by calling
-@code{readonly_data_section} or one of the alternatives for other
-sections. @var{align} is the constant alignment in bits.
+case of a @code{const_int} rtx. @var{align} is the constant alignment
+in bits.
The default version of this function takes care of putting symbolic
constants in @code{flag_pic} mode in @code{data_section} and everything
this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
@end defmac
-@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
-programs. In some of these environments, position-independent code
-requires not only the use of different addressing modes, but also
-special code to enable the use of these addressing modes.
-
-The @code{FINALIZE_PIC} macro serves as a hook to emit these special
-codes once the function is being compiled into assembly code, but not
-before. (It is not done before, because in the case of compiling an
-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
-
@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.
@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
-be a simple @code{long int}. For the others, it should be an array of
-@code{long int}. The number of elements in this array is determined by
-the size of the desired target floating point data type: 32 bits of it
-go in each @code{long int} array element. Each array element holds 32
-bits of the result, even if @code{long int} is wider than 32 bits on the
-host machine.
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@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} and
+@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a
+simple @code{long int}. For the others, it should be an array of
+@code{long int}. The number of elements in this array is determined
+by the size of the desired target floating point data type: 32 bits of
+it go in each @code{long int} array element. Each array element holds
+32 bits of the result, even if @code{long int} is wider than 32 bits
+on the host machine.
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
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
to make @var{name} weak.
@end defmac
+@defmac ASM_OUTPUT_WEAKREF (@var{stream}, @var{decl}, @var{name}, @var{value})
+Outputs a directive that enables @var{name} to be used to refer to
+symbol @var{value} with weak-symbol semantics. @code{decl} is the
+declaration of @code{name}.
+@end defmac
+
@defmac SUPPORTS_WEAK
A C expression which evaluates to true if the target supports weak symbols.
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
The default is that FDEs are not given nonlocal labels.
@end deftypefn
-@deftypefn {Taget Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn})
+@deftypefn {Target Hook} void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (@var{stream})
+This target hook emits a label at the beginning of the exception table.
+It should be defined on targets where it is desirable for the table
+to be broken up according to function.
+
+The default is that no label is emitted.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn})
This target hook emits and assembly directives required to unwind the
given instruction. This is only used when TARGET_UNWIND_INFO is set.
@end deftypefn
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.
these will be output by @code{TARGET_UNWIND_EMIT}.
@end defmac
+@deftypevar {Target Hook} bool TARGET_UNWID_TABLES_DEFAULT
+This variable should be set to @code{true} if the target ABI requires unwinding
+tables even when exceptions are not used.
+@end deftypevar
+
@defmac MUST_USE_SJLJ_EXCEPTIONS
This macro need only be defined if @code{DWARF2_UNWIND_INFO} is
runtime-variable. In that case, @file{except.h} cannot correctly
the target supports DWARF 2 frame unwind information.
@end defmac
-@deftypefn {Target Hook} void TARGET_ASM_EXCEPTION_SECTION ()
-If defined, a function that switches to the section in which the main
-exception table is to be placed (@pxref{Sections}). The default is a
-function that switches to a section named @code{.gcc_except_table} on
-machines that support named sections via
-@code{TARGET_ASM_NAMED_SECTION}, otherwise if @option{-fpic} or
-@option{-fPIC} is in effect, the @code{data_section}, otherwise the
-@code{readonly_data_section}.
-@end deftypefn
-
-@deftypefn {Target Hook} void TARGET_ASM_EH_FRAME_SECTION ()
-If defined, a function that switches to the section in which the DWARF 2
-frame unwind information to be placed (@pxref{Sections}). The default
-is a function that outputs a standard GAS section directive, if
-@code{EH_FRAME_SECTION_NAME} is defined, or else a data section
-directive followed by a synthetic label.
-@end deftypefn
-
@deftypevar {Target Hook} bool TARGET_TERMINATE_DW2_EH_FRAME_INFO
Contains the value true if the target should add a zero word onto the
end of a Dwarf-2 frame info section when used for exception handling.
If not defined, the default is to return @code{NULL_RTX}.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_ASM_TTYPE (rtx @var{sym})
+This hook is used to output a reference from a frame unwinding table to
+the type_info object identified by @var{sym}. It should return @code{true}
+if the reference was output. Returning @code{false} will cause the
+reference to be output using the normal Dwarf2 routines.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_ARM_EABI_UNWINDER
+This hook should be set to @code{true} on targets that use an ARM EABI
+based unwinding library, and @code{false} on other targets. This effects
+the format of unwinding tables, and how the unwinder in entered after
+running a cleanup. The default is @code{false}.
+@end deftypefn
+
@node Alignment Output
@subsection Assembler Commands for Alignment
reference to the given label, using an integer of the given size.
@end defmac
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *@var{FILE}, int @var{size}, rtx @var{x})
+If defined, this target hook is a function which outputs a DTP-relative
+reference to the given TLS symbol of the specified size.
+@end deftypefn
+
@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
@file{i386/i386.c}, for example.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_VALID_DLLIMPORT_ATTRIBUTE_P (tree @var{decl})
+@var{decl} is a variable or function with @code{__attribute__((dllimport))}
+specified. Use this hook if the target needs to add extra validation
+checks to @code{handle_dll_attribute}.
+@end deftypefn
+
@defmac TARGET_DECLSPEC
Define this macro to a nonzero value if you want to treat
@code{__declspec(X)} as equivalent to @code{__attribute((X))}. By
@section Parameters for Precompiled Header Validity Checking
@cindex parameters, precompiled headers
-@deftypefn {Target Hook} void * TARGET_GET_PCH_VALIDITY (size_t * @var{sz})
-Define this hook if your target needs to check a different collection
-of flags than the default, which is every flag defined by
-@code{TARGET_SWITCHES} and @code{TARGET_OPTIONS}. It should return
-some data which will be saved in the PCH file and presented to
-@code{TARGET_PCH_VALID_P} later; it should set @code{SZ} to the size
-of the data.
+@deftypefn {Target Hook} void *TARGET_GET_PCH_VALIDITY (size_t *@var{sz})
+This hook returns the data needed by @code{TARGET_PCH_VALID_P} and sets
+@samp{*@var{sz}} to the size of the data in bytes.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_PCH_VALID_P (const void *@var{data}, size_t @var{sz})
+This hook checks whether the options used to create a PCH file are
+compatible with the current settings. It returns @code{NULL}
+if so and a suitable error message if not. Error messages will
+be presented to the user and must be localized using @samp{_(@var{msg})}.
+
+@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}
+when the PCH file was created and @var{sz} is the size of that data in bytes.
+It's safe to assume that the data was created by the same version of the
+compiler, so no format checking is needed.
+
+The default definition of @code{default_pch_valid_p} should be
+suitable for most targets.
@end deftypefn
-@deftypefn {Target Hook} const char * TARGET_PCH_VALID_P (const void * @var{data}, size_t @var{sz})
-Define this hook if your target needs to check a different collection of
-flags than the default, which is every flag defined by @code{TARGET_SWITCHES}
-and @code{TARGET_OPTIONS}. It is given data which came from
-@code{TARGET_GET_PCH_VALIDITY} (in this version of this compiler, so there
-is no need for extensive validity checking). It returns @code{NULL} if
-it is safe to load a PCH file with this data, or a suitable error message
-if not. The error message will be presented to the user, so it should
-be localized.
+@deftypefn {Target Hook} const char *TARGET_CHECK_PCH_TARGET_FLAGS (int @var{pch_flags})
+If this hook is nonnull, the default implementation of
+@code{TARGET_PCH_VALID_P} will use it to check for compatible values
+of @code{target_flags}. @var{pch_flags} specifies the value that
+@code{target_flags} had when the PCH file was created. The return
+value is the same as for @code{TARGET_PCH_VALID_P}.
@end deftypefn
@node C++ ABI
method. The default is to return @code{true}.
@end deftypefn
-@deftypefn {Target Hook} bool TARGET_CXX_EXPORT_CLASS_DATA (void)
-If this hook returns false (the default), then virtual tables and RTTI
-data structures will have the ELF visibility of their containing
-class. If this hook returns true, then these data structures will
-have ELF ``default'' visibility, independently of the visibility of
-the containing class.
+@deftypefn {Target Hook} void TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY (tree @var{decl})
+@var{decl} is a virtual table, virtual table table, typeinfo object,
+or other similar implicit class data object that will be emitted with
+external linkage in this translation unit. No ELF visibility has been
+explicitly specified. If the target needs to specify a visibility
+other than that of the containing class, use this hook to set
+@code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT (void)
+This hook returns true (the default) if virtual tables and other
+similar implicit class data objects are always COMDAT if they have
+external linkage. If this hook returns false, then class data for
+classes whose virtual table will be emitted in only one translation
+unit will not be COMDAT.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_USE_AEABI_ATEXIT (void)
+This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)
+should be used to register static destructors when @option{-fuse-cxa-atexit}
+is in effect. The default is to return false to use @code{__cxa_atexit}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree @var{type})
+@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just been
+defined. Use this hook to make adjustments to the class (eg, tweak
+visibility or perform any other required target modifications).
@end deftypefn
@node Misc
@c prevent bad page break with this line
Here are several miscellaneous parameters.
-@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
-predicate and the second field is an array of rtl codes. For each
-predicate, list all rtl codes that can be in expressions matched by the
-predicate. The list should have a trailing comma. Here is an example
-of two entries in the list for a typical RISC machine:
-
-@smallexample
-#define PREDICATE_CODES \
- @{"gen_reg_rtx_operand", @{SUBREG, REG@}@}, \
- @{"reg_or_short_cint_operand", @{SUBREG, REG, CONST_INT@}@},
-@end smallexample
-
-Defining this macro does not affect the generated code (however,
-incorrect definitions that omit an rtl code that may be matched by the
-predicate can cause the compiler to malfunction). Instead, it allows
-the table built by @file{genrecog} to be more compact and efficient,
-thus speeding up the compiler. The most important predicates to include
-in the list specified by this macro are those used in the most insn
-patterns.
-
-For each predicate function named in @code{PREDICATE_CODES}, a
-declaration will be generated in @file{insn-codes.h}.
-
-Use of this macro is deprecated; use @code{define_predicate} instead.
-@xref{Defining Predicates}.
-@end defmac
-
-@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
-listed in @code{SPECIAL_MODE_PREDICATES}, the warning will be
-suppressed.
-
-Here is an example from the IA-32 port (@code{ext_register_operand}
-specially checks for @code{HImode} or @code{SImode} in preparation
-for a byte extraction from @code{%ah} etc.).
-
-@smallexample
-#define SPECIAL_MODE_PREDICATES \
- "ext_register_operand",
-@end smallexample
-
-Use of this macro is deprecated; use @code{define_special_predicate}
-instead. @xref{Defining Predicates}.
-@end defmac
-
@defmac HAS_LONG_COND_BRANCH
Define this boolean macro to indicate whether or not your architecture
has conditional branches that can span all of memory. It is used in
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.
unsigned one.
@end defmac
+@deftypefn {Target Hook} int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum machine_mode @var{mode})
+When @option{-ffast-math} is in effect, GCC tries to optimize
+divisions by the same divisor, by turning them into multiplications by
+the reciprocal. This target hook specifies the minimum number of divisions
+that should be there for GCC to perform the optimization for a variable
+of mode @var{mode}. The default implementation returns 3 if the machine
+has an instruction for the division, and 2 if it does not.
+@end deftypefn
+
@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
@defmac VECTOR_STORE_FLAG_VALUE (@var{mode})
-A C expression that gives a rtx representing the non-zero true element
+A C expression that gives a rtx representing the nonzero true element
for vector comparisons. The returned rtx should be valid for the inner
mode of @var{mode} which is guaranteed to be a vector mode. Define
this macro on machines that have vector comparison operations that
@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
@code{NULL} to put the pragma in the global namespace. The callback
routine receives @var{pfile} as its first argument, which can be passed
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
+@var{name} by calling @code{pragma_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}.
-Note that the use of @code{c_lex} is specific to the C and C++
+Note that the use of @code{pragma_lex} is specific to the C and C++
compilers. It will not work in the Java or Fortran compilers, or any
-other language compilers for that matter. Thus if @code{c_lex} is going
+other language compilers for that matter. Thus if @code{pragma_lex} is going
to be called from target-specific code, it must only be done so when
building the C and C++ compilers. This can be done by defining the
variables @code{c_target_objs} and @code{cxx_target_objs} in the
target entry in the @file{config.gcc} file. These variables should name
the target-specific, language-specific object file which contains the
-code that uses @code{c_lex}. Note it will also be necessary to add a
+code that uses @code{pragma_lex}. Note it will also be necessary to add a
rule to the makefile fragment pointed to by @code{tmake_file} that shows
how to build this object file.
@end deftypefun
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).
+the machine default), define this macro to the necessary value (in bytes).
This must be a value that would also valid to be used with
@samp{#pragma pack()} (that is, a small power of two).
@end defmac
You need not define this macro if it would always evaluate to zero.
@end defmac
-@deftypefn {Target Hook} tree TARGET_MD_ASM_CLOBBERS (tree @var{clobbers})
+@deftypefn {Target Hook} tree TARGET_MD_ASM_CLOBBERS (tree @var{outputs}, tree @var{inputs}, tree @var{clobbers})
This target hook should add to @var{clobbers} @code{STRING_CST} trees for
-any hard regs the port wishes to automatically clobber for all asms.
+any hard regs the port wishes to automatically clobber for an asm.
It should return the result of the last @code{tree_cons} used to add a
-clobber.
+clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the
+corresponding parameters to the asm and may be inspected to avoid
+clobbering a register that is an input or output of the asm. You can use
+@code{decl_overlaps_hard_reg_set_p}, declared in @file{tree.h}, to test
+for overlap with regards to asm-declared registers.
@end deftypefn
@defmac MATH_LIBRARY
is wrong.
@end defmac
-@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
+@defmac TARGET_POSIX_IO
+Define this macro if the target supports the following POSIX@ file
+functions, access, mkdir and file locking with fcntl / F_SETLKW@.
+Defining @code{TARGET_POSIX_IO} will enable the test coverage code
to use file locking when exiting a program, which avoids race conditions
-if the program has forked.
+if the program has forked. It will also create directories at run-time
+for cross-profiling.
@end defmac
@defmac MAX_CONDITIONAL_EXECUTE
built-in function.
@end deftypefn
+@deftypefn {Target Hook} tree TARGET_RESOLVE_OVERLOADED_BUILTIN (tree @var{fndecl}, tree @var{arglist})
+
+Select a replacement for a machine specific built-in function that
+was set up by @samp{TARGET_INIT_BUILTINS}. This is done
+@emph{before} regular type checking, and so allows the target to
+implement a crude form of function overloading. @var{fndecl} is the
+declaration of the built-in function. @var{arglist} is the list of
+arguments passed to the built-in function. The result is a
+complete expression that implements the operation, usually
+another @code{CALL_EXPR}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_FOLD_BUILTIN (tree @var{fndecl}, tree @var{arglist}, bool @var{ignore})
+
+Fold a call to a machine specific built-in function that was set up by
+@samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the
+built-in function. @var{arglist} is the list of arguments passed to
+the built-in function. 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
+
+@deftypefn {Target Hook} const char * TARGET_INVALID_WITHIN_DOLOOP (rtx @var{insn})
+
+Take an instruction in @var{insn} and return NULL if it is valid within a
+low-overhead loop, otherwise return a string why doloop could not be applied.
+
+Many targets use special registers for low-overhead looping. For any
+instruction that clobbers these this function should return a string indicating
+the reason why the doloop could not be applied.
+By default, the RTL loop optimizer does not use a present doloop pattern for
+loops containing function calls or branch on table instructions.
+@end deftypefn
+
@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
Take a branch insn in @var{branch1} and another in @var{branch2}.
may in turn cause a branch offset to overflow.
@end defmac
-@defmac ALLOCATE_INITIAL_VALUE (@var{hard_reg})
+@deftypefn {Target Hook} bool TARGET_COMMUTATIVE_P (rtx @var{x}, @var{outer_code})
+This target hook returns @code{true} if @var{x} is considered to be commutative.
+Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider
+PLUS to be commutative inside a MEM. @var{outer_code} is the rtx code
+of the enclosing rtl, if known, otherwise it is UNKNOWN.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_ALLOCATE_INITIAL_VALUE (rtx @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
to this pseudo register, because the original hard register or a stack slot
-it has been saved into can be used. @code{ALLOCATE_INITIAL_VALUE}, if
-defined, is called at the start of register allocation once for each
-hard register that had its initial value copied by using
+it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}
+is called at the start of register allocation once for each hard register
+that had its initial value copied by using
@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.
Possible values are @code{NULL_RTX}, if you don't want
to do any special allocation, a @code{REG} rtx---that would typically be
@code{MEM}.
If you are returning a @code{MEM}, this is only a hint for the allocator;
it might decide to use another register anyways.
-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
+You may use @code{current_function_leaf_function} in the hook, functions
+that use @code{REG_N_SETS}, to determine if the hard
register in question will not be clobbered.
-@end defmac
+The default value of this hook is @code{NULL}, which disables any special
+allocation.
+@end deftypefn
@defmac TARGET_OBJECT_SUFFIX
Define this macro to be a C string representing the suffix for object
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
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_CONVERSION (tree @var{fromtype}, tree @var{totype})
+If defined, this macro returns the diagnostic message when it is
+invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}
+if validity should be determined by the front end.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_UNARY_OP (int @var{op}, tree @var{type})
+If defined, this macro returns the diagnostic message when it is
+invalid to apply operation @var{op} (where unary plus is denoted by
+@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}
+if validity should be determined by the front end.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_BINARY_OP (int @var{op}, tree @var{type1}, tree @var{type2})
+If defined, this macro returns the diagnostic message when it is
+invalid to apply operation @var{op} to operands of types @var{type1}
+and @var{type2}, or @code{NULL} if validity should be determined by
+the front end.
+@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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