-@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
-@c 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1988-2015 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
* Type Layout:: Defining sizes and properties of basic user data types.
* Registers:: Naming and describing the hardware registers.
* Register Classes:: Defining the classes of hardware registers.
-* Old Constraints:: The old way to define machine-specific constraints.
* Stack and Calling:: Defining which way the stack grows and by how much.
* Varargs:: Defining the varargs macros.
* Trampolines:: Code set up at run time to enter a nested function.
@defmac USE_LD_AS_NEEDED
A macro that controls the modifications to @code{LIBGCC_SPEC}
mentioned in @code{REAL_LIBGCC_SPEC}. If nonzero, a spec will be
-generated that uses --as-needed and the shared libgcc in place of the
+generated that uses @option{--as-needed} or equivalent options and the
+shared @file{libgcc} in place of the
static exception handler library, when linking without any of
@code{-static}, @code{-static-libgcc}, or @code{-shared-libgcc}.
@end defmac
@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched
when the compiler is built as a cross
compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it
-to the list of directories used to find the assembler in @file{configure.in}.
+to the list of directories used to find the assembler in @file{configure.ac}.
@end defmac
@defmac STANDARD_STARTFILE_PREFIX
@hook TARGET_CHECK_STRING_OBJECT_FORMAT_ARG
@hook TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE
-This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}
-but is called when the optimize level is changed via an attribute or
-pragma or when it is reset at the end of the code affected by the
-attribute or pragma. It is not called at the beginning of compilation
-when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these
-actions then, you should have @code{TARGET_OPTION_OVERRIDE} call
-@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.
-@end deftypefn
@defmac C_COMMON_OVERRIDE_OPTIONS
This is similar to the @code{TARGET_OPTION_OVERRIDE} hook
is 0.
@end defmac
+@hook TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P
+
@node Per-Function Data
@section Defining data structures for per-function information.
@cindex per-function data
multi-word integers.
@end defmac
-@defmac BITS_PER_UNIT
-Define this macro to be the number of bits in an addressable storage
-unit (byte). If you do not define this macro the default is 8.
-@end defmac
-
@defmac BITS_PER_WORD
Number of bits in a word. If you do not define this macro, the default
is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
@end defmac
@hook TARGET_PROMOTE_FUNCTION_MODE
-Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or
-function return values. The target hook should return the new mode
-and possibly change @code{*@var{punsignedp}} if the promotion should
-change signedness. This function is called only for scalar @emph{or
-pointer} types.
-
-@var{for_return} allows to distinguish the promotion of arguments and
-return values. If it is @code{1}, a return value is being promoted and
-@code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.
-If it is @code{2}, the returned mode should be that of the register in
-which an incoming parameter is copied, or the outgoing result is computed;
-then the hook should return the same mode as @code{promote_mode}, though
-the signedness may be different.
-
-@var{type} can be NULL when promoting function arguments of libcalls.
-
-The default is to not promote arguments and return values. You can
-also define the hook to @code{default_promote_function_mode_always_promote}
-if you would like to apply the same rules given by @code{PROMOTE_MODE}.
-@end deftypefn
@defmac PARM_BOUNDARY
Normal alignment required for function parameters on the stack, in
just the biggest alignment that, when violated, may cause a fault.
@end defmac
+@hook TARGET_ABSOLUTE_BIGGEST_ALIGNMENT
+
@defmac MALLOC_ABI_ALIGNMENT
Alignment, in bits, a C conformant malloc implementation has to
provide. If not defined, the default value is @code{BITS_PER_WORD}.
On systems that use ELF, the default (in @file{config/elfos.h}) is
the largest supported 32-bit ELF section alignment representable on
-a 32-bit host e.g. @samp{(((unsigned HOST_WIDEST_INT) 1 << 28) * 8)}.
+a 32-bit host e.g. @samp{(((uint64_t) 1 << 28) * 8)}.
On 32-bit ELF the largest supported section alignment in bits is
@samp{(0x80000000 * 8)}, but this is not representable on 32-bit hosts.
@end defmac
constants to character arrays can be done inline.
@end defmac
+@defmac DATA_ABI_ALIGNMENT (@var{type}, @var{basic-align})
+Similar to @code{DATA_ALIGNMENT}, but for the cases where the ABI mandates
+some alignment increase, instead of optimization only purposes. E.g.@
+AMD x86-64 psABI says that variables with array type larger than 15 bytes
+must be aligned to 16 byte boundaries.
+
+If this macro is not defined, then @var{basic-align} is used.
+@end defmac
+
@defmac CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
If defined, a C expression to compute the alignment given to a constant
that is being placed in memory. @var{constant} is the constant and
@end defmac
@hook TARGET_ALIGN_ANON_BITFIELD
-When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine
-whether unnamed bitfields affect the alignment of the containing
-structure. The hook should return true if the structure should inherit
-the alignment requirements of an unnamed bitfield's type.
-@end deftypefn
@hook TARGET_NARROW_VOLATILE_BITFIELD
-This target hook should return @code{true} if accesses to volatile bitfields
-should use the narrowest mode possible. It should return @code{false} if
-these accesses should use the bitfield container type.
-
-The default is @code{!TARGET_STRICT_ALIGN}.
-@end deftypefn
@hook TARGET_MEMBER_TYPE_FORCES_BLK
-Return true if a structure, union or array containing @var{field} should
-be accessed using @code{BLKMODE}.
-
-If @var{field} is the only field in the structure, @var{mode} is its
-mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the
-case where structures of one field would require the structure's mode to
-retain the field's mode.
-
-Normally, this is not needed.
-@end deftypefn
@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
Define this macro as an expression for the alignment of a type (given
@end defmac
@defmac STACK_SAVEAREA_MODE (@var{save_level})
-If defined, an expression of type @code{enum machine_mode} that
+If defined, an expression of type @code{machine_mode} that
specifies the mode of the save area operand of a
@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
@var{save_level} is one of @code{SAVE_BLOCK}, @code{SAVE_FUNCTION}, or
@end defmac
@defmac STACK_SIZE_MODE
-If defined, an expression of type @code{enum machine_mode} that
+If defined, an expression of type @code{machine_mode} that
specifies the mode of the size increment operand of an
@code{allocate_stack} named pattern (@pxref{Standard Names}).
@end defmac
@hook TARGET_LIBGCC_CMP_RETURN_MODE
-This target hook should return the mode to be used for the return value
-of compare instructions expanded to libgcc calls. If not defined
-@code{word_mode} is returned which is the right choice for a majority of
-targets.
-@end deftypefn
@hook TARGET_LIBGCC_SHIFT_COUNT_MODE
-This target hook should return the mode to be used for the shift count operand
-of shift instructions expanded to libgcc calls. If not defined
-@code{word_mode} is returned which is the right choice for a majority of
-targets.
-@end deftypefn
@hook TARGET_UNWIND_WORD_MODE
-Return machine mode to be used for @code{_Unwind_Word} type.
-The default is to use @code{word_mode}.
-@end deftypefn
-
-@defmac ROUND_TOWARDS_ZERO
-If defined, this macro should be true if the prevailing rounding
-mode is towards zero.
-
-Defining this macro only affects the way @file{libgcc.a} emulates
-floating-point arithmetic.
-
-Not defining this macro is equivalent to returning zero.
-@end defmac
-
-@defmac LARGEST_EXPONENT_IS_NORMAL (@var{size})
-This macro should return true if floats with @var{size}
-bits do not have a NaN or infinity representation, but use the largest
-exponent for normal numbers instead.
-
-Defining this macro only affects the way @file{libgcc.a} emulates
-floating-point arithmetic.
-
-The default definition of this macro returns false for all sizes.
-@end defmac
@hook TARGET_MS_BITFIELD_LAYOUT_P
-This target hook returns @code{true} if bit-fields in the given
-@var{record_type} are to be laid out following the rules of Microsoft
-Visual C/C++, namely: (i) a bit-field won't share the same storage
-unit with the previous bit-field if their underlying types have
-different sizes, and the bit-field will be aligned to the highest
-alignment of the underlying types of itself and of the previous
-bit-field; (ii) a zero-sized bit-field will affect the alignment of
-the whole enclosing structure, even if it is unnamed; except that
-(iii) a zero-sized bit-field will be disregarded unless it follows
-another bit-field of nonzero size. If this hook returns @code{true},
-other macros that control bit-field layout are ignored.
-
-When a bit-field is inserted into a packed record, the whole size
-of the underlying type is used by one or more same-size adjacent
-bit-fields (that is, if its long:3, 32 bits is used in the record,
-and any additional adjacent long bit-fields are packed into the same
-chunk of 32 bits. However, if the size changes, a new field of that
-size is allocated). In an unpacked record, this is the same as using
-alignment, but not equivalent when packing.
-
-If both MS bit-fields and @samp{__attribute__((packed))} are used,
-the latter will take precedence. If @samp{__attribute__((packed))} is
-used on a single field when MS bit-fields are in use, it will take
-precedence for that field, but the alignment of the rest of the structure
-may affect its placement.
-@end deftypefn
@hook TARGET_DECIMAL_FLOAT_SUPPORTED_P
-Returns true if the target supports decimal floating point.
-@end deftypefn
@hook TARGET_FIXED_POINT_SUPPORTED_P
-Returns true if the target supports fixed-point arithmetic.
-@end deftypefn
@hook TARGET_EXPAND_TO_RTL_HOOK
-This hook is called just before expansion into rtl, allowing the target
-to perform additional initializations or analysis before the expansion.
-For example, the rs6000 port uses it to allocate a scratch stack slot
-for use in copying SDmode values between memory and floating point
-registers whenever the function being expanded has any SDmode
-usage.
-@end deftypefn
@hook TARGET_INSTANTIATE_DECLS
-This hook allows the backend to perform additional instantiations on rtl
-that are not actually in any insns yet, but will be later.
-@end deftypefn
@hook TARGET_MANGLE_TYPE
-If your target defines any fundamental types, or any types your target
-uses should be mangled differently from the default, define this hook
-to return the appropriate encoding for these types as part of a C++
-mangled name. The @var{type} argument is the tree structure representing
-the type to be mangled. The hook may be applied to trees which are
-not target-specific fundamental types; it should return @code{NULL}
-for all such types, as well as arguments it does not recognize. If the
-return value is not @code{NULL}, it must point to a statically-allocated
-string constant.
-
-Target-specific fundamental types might be new fundamental types or
-qualified versions of ordinary fundamental types. Encode new
-fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}
-is the name used for the type in source code, and @var{n} is the
-length of @var{name} in decimal. Encode qualified versions of
-ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where
-@var{name} is the name used for the type qualifier in source code,
-@var{n} is the length of @var{name} as above, and @var{code} is the
-code used to represent the unqualified version of this type. (See
-@code{write_builtin_type} in @file{cp/mangle.c} for the list of
-codes.) In both cases the spaces are for clarity; do not include any
-spaces in your string.
-
-This hook is applied to types prior to typedef resolution. If the mangled
-name for a particular type depends only on that type's main variant, you
-can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}
-before mangling.
-
-The default version of this hook always returns @code{NULL}, which is
-appropriate for a target that does not define any new fundamental
-types.
-@end deftypefn
@node Type Layout
@section Layout of Source Language Data Types
@code{BITS_PER_UNIT * 16}.
@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{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{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 LIBGCC2_GNU_PREFIX
This macro corresponds to the @code{TARGET_LIBFUNC_GNU_PREFIX} target
hook and should be defined if that hook is overriden to be true. It
the libgcc @file{config.host}.
@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{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
@end defmac
@hook TARGET_DEFAULT_SHORT_ENUMS
-This target hook should return true if the compiler should give an
-@code{enum} type only as many bytes as it takes to represent the range
-of possible values of that type. It should return false if all
-@code{enum} types should be allocated like @code{int}.
-
-The default is to return false.
-@end deftypefn
@defmac SIZE_TYPE
A C expression for a string describing the name of the data type to use
@findex reg_names
@findex reg_class_contents
@hook TARGET_CONDITIONAL_REGISTER_USAGE
-This hook may conditionally modify five variables
-@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},
-@code{reg_names}, and @code{reg_class_contents}, to take into account
-any dependence of these register sets on target flags. The first three
-of these are of type @code{char []} (interpreted as Boolean vectors).
-@code{global_regs} is a @code{const char *[]}, and
-@code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is
-called, @code{fixed_regs}, @code{call_used_regs},
-@code{reg_class_contents}, and @code{reg_names} have been initialized
-from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},
-@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.
-@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},
-@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}
-command options have been applied.
-
-@cindex disabling certain registers
-@cindex controlling register usage
-If the usage of an entire class of registers depends on the target
-flags, you may indicate this to GCC by using this macro to modify
-@code{fixed_regs} and @code{call_used_regs} to 1 for each of the
-registers in the classes which should not be used by GCC@. Also define
-the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT}
-to return @code{NO_REGS} if it
-is called with a letter for a class that shouldn't be used.
-
-(However, if this class is not included in @code{GENERAL_REGS} and all
-of the insn patterns whose constraints permit this class are
-controlled by target switches, then GCC will automatically avoid using
-these registers when the target switches are opposed to them.)
-@end deftypefn
@defmac INCOMING_REGNO (@var{out})
Define this macro if the target machine has register windows. This C
prologue and restoring it in the epilogue. This discourages it from
using call-saved registers. If a machine wants to ensure that IRA
allocates registers in the order given by REG_ALLOC_ORDER even if some
-call-saved registers appear earlier than call-used ones, this macro
-should be defined.
+call-saved registers appear earlier than call-used ones, then define this
+macro as a C expression to nonzero. Default is 0.
@end defmac
@defmac IRA_HARD_REGNO_ADD_COST_MULTIPLIER (@var{regno})
@end defmac
@hook TARGET_HARD_REGNO_SCRATCH_OK
-This target hook should return @code{true} if it is OK to use a hard register
-@var{regno} as scratch reg in peephole2.
-
-One common use of this macro is to prevent using of a register that
-is not saved by a prologue in an interrupt handler.
-
-The default version of this hook always returns @code{true}.
-@end deftypefn
@defmac AVOID_CCMODE_COPIES
Define this macro if the compiler should avoid copies to/from @code{CCmode}
@hook TARGET_PREFERRED_RENAME_CLASS
@hook TARGET_PREFERRED_RELOAD_CLASS
-A target hook that places additional restrictions on the register class
-to use when it is necessary to copy value @var{x} into a register in class
-@var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps
-another, smaller class.
-
-The default version of this hook always returns value of @code{rclass} argument.
-
-Sometimes returning a more restrictive class makes better code. For
-example, on the 68000, when @var{x} is an integer constant that is in range
-for a @samp{moveq} instruction, the value of this macro is always
-@code{DATA_REGS} as long as @var{rclass} includes the data registers.
-Requiring a data register guarantees that a @samp{moveq} will be used.
-
-One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return
-@var{rclass} is if @var{x} is a legitimate constant which cannot be
-loaded into some register class. By returning @code{NO_REGS} you can
-force @var{x} into a memory location. For example, rs6000 can load
-immediate values into general-purpose registers, but does not have an
-instruction for loading an immediate value into a floating-point
-register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when
-@var{x} is a floating-point constant. If the constant can't be loaded
-into any kind of register, code generation will be better if
-@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead
-of using @code{TARGET_PREFERRED_RELOAD_CLASS}.
-
-If an insn has pseudos in it after register allocation, reload will go
-through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}
-to find the best one. Returning @code{NO_REGS}, in this case, makes
-reload add a @code{!} in front of the constraint: the x86 back-end uses
-this feature to discourage usage of 387 registers when math is done in
-the SSE registers (and vice versa).
-@end deftypefn
@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
A C expression that places additional restrictions on the register class
@end defmac
@hook TARGET_PREFERRED_OUTPUT_RELOAD_CLASS
-Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of
-input reloads.
-
-The default version of this hook always returns value of @code{rclass}
-argument.
-
-You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage
-reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.
-@end deftypefn
@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
A C expression that places additional restrictions on the register class
@end defmac
@hook TARGET_SECONDARY_RELOAD
-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. 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 than
-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 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_class}
-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.]
-
-
-@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})
@end defmac
@hook TARGET_CLASS_LIKELY_SPILLED_P
-A target hook which returns @code{true} if pseudos that have been assigned
-to registers of class @var{rclass} would likely be spilled because
-registers of @var{rclass} are needed for spill registers.
-
-The default version of this target hook returns @code{true} if @var{rclass}
-has exactly one register and @code{false} otherwise. On most machines, this
-default should be used. Only use this target hook to some other expression
-if pseudos allocated by @file{local-alloc.c} end up in memory because their
-hard registers were needed for spill registers. If this target hook returns
-@code{false} for those classes, those pseudos will only be allocated by
-@file{global.c}, which knows how to reallocate the pseudo to another
-register. If there would not be another register available for reallocation,
-you should not change the implementation of this target hook since
-the only effect of such implementation would be to slow down register
-allocation.
-@end deftypefn
@hook TARGET_CLASS_MAX_NREGS
-A target hook returns the maximum number of consecutive registers
-of class @var{rclass} needed to hold a value of mode @var{mode}.
-
-This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,
-the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},
-@var{mode})} target hook should be the maximum value of
-@code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}
-values in the class @var{rclass}.
-
-This target hook helps control the handling of multiple-word values
-in the reload pass.
-
-The default version of this target hook returns the size of @var{mode}
-in words.
-@end deftypefn
@defmac CLASS_MAX_NREGS (@var{class}, @var{mode})
A C expression for the maximum number of consecutive registers
@end smallexample
@end defmac
+@hook TARGET_IRA_CHANGE_PSEUDO_ALLOCNO_CLASS
+
@hook TARGET_LRA_P
@hook TARGET_REGISTER_PRIORITY
+@hook TARGET_REGISTER_USAGE_LEVELING_P
+
@hook TARGET_DIFFERENT_ADDR_DISPLACEMENT_P
+@hook TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P
+
+@hook TARGET_LEGITIMIZE_ADDRESS_DISPLACEMENT
+
@hook TARGET_SPILL_CLASS
-@node Old Constraints
-@section Obsolete Macros for Defining Constraints
-@cindex defining constraints, obsolete method
-@cindex constraints, defining, obsolete method
-
-Machine-specific constraints can be defined with these macros instead
-of the machine description constructs described in @ref{Define
-Constraints}. This mechanism is obsolete. New ports should not use
-it; old ports should convert to the new mechanism.
-
-@defmac CONSTRAINT_LEN (@var{char}, @var{str})
-For the constraint at the start of @var{str}, which starts with the letter
-@var{c}, return the length. This allows you to have register class /
-constant / extra constraints that are longer than a single letter;
-you don't need to define this macro if you can do with single-letter
-constraints only. The definition of this macro should use
-DEFAULT_CONSTRAINT_LEN for all the characters that you don't want
-to handle specially.
-There are some sanity checks in genoutput.c that check the constraint lengths
-for the md file, so you can also use this macro to help you while you are
-transitioning from a byzantine single-letter-constraint scheme: when you
-return a negative length for a constraint you want to re-use, genoutput
-will complain about every instance where it is used in the md file.
-@end defmac
-
-@defmac REG_CLASS_FROM_LETTER (@var{char})
-A C expression which defines the machine-dependent operand constraint
-letters for register classes. If @var{char} is such a letter, the
-value should be the register class corresponding to it. Otherwise,
-the value should be @code{NO_REGS}. The register letter @samp{r},
-corresponding to class @code{GENERAL_REGS}, will not be passed
-to this macro; you do not need to handle it.
-@end defmac
-
-@defmac REG_CLASS_FROM_CONSTRAINT (@var{char}, @var{str})
-Like @code{REG_CLASS_FROM_LETTER}, but you also get the constraint string
-passed in @var{str}, so that you can use suffixes to distinguish between
-different variants.
-@end defmac
-
-@defmac CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
-A C expression that defines the machine-dependent operand constraint
-letters (@samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}) that specify
-particular ranges of integer values. If @var{c} is one of those
-letters, the expression should check that @var{value}, an integer, is in
-the appropriate range and return 1 if so, 0 otherwise. If @var{c} is
-not one of those letters, the value should be 0 regardless of
-@var{value}.
-@end defmac
-
-@defmac CONST_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
-Like @code{CONST_OK_FOR_LETTER_P}, but you also get the constraint
-string passed in @var{str}, so that you can use suffixes to distinguish
-between different variants.
-@end defmac
-
-@defmac CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
-A C expression that defines the machine-dependent operand constraint
-letters that specify particular ranges of @code{const_double} values
-(@samp{G} or @samp{H}).
-
-If @var{c} is one of those letters, the expression should check that
-@var{value}, an RTX of code @code{const_double}, is in the appropriate
-range and return 1 if so, 0 otherwise. If @var{c} is not one of those
-letters, the value should be 0 regardless of @var{value}.
-
-@code{const_double} is used for all floating-point constants and for
-@code{DImode} fixed-point constants. A given letter can accept either
-or both kinds of values. It can use @code{GET_MODE} to distinguish
-between these kinds.
-@end defmac
-
-@defmac CONST_DOUBLE_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
-Like @code{CONST_DOUBLE_OK_FOR_LETTER_P}, but you also get the constraint
-string passed in @var{str}, so that you can use suffixes to distinguish
-between different variants.
-@end defmac
-
-@defmac EXTRA_CONSTRAINT (@var{value}, @var{c})
-A C expression that defines the optional machine-dependent constraint
-letters that can be used to segregate specific types of operands, usually
-memory references, for the target machine. Any letter that is not
-elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER} /
-@code{REG_CLASS_FROM_CONSTRAINT}
-may be used. Normally this macro will not be defined.
-
-If it is required for a particular target machine, it should return 1
-if @var{value} corresponds to the operand type represented by the
-constraint letter @var{c}. If @var{c} is not defined as an extra
-constraint, the value returned should be 0 regardless of @var{value}.
-
-For example, on the ROMP, load instructions cannot have their output
-in r0 if the memory reference contains a symbolic address. Constraint
-letter @samp{Q} is defined as representing a memory address that does
-@emph{not} contain a symbolic address. An alternative is specified with
-a @samp{Q} constraint on the input and @samp{r} on the output. The next
-alternative specifies @samp{m} on the input and a register class that
-does not include r0 on the output.
-@end defmac
-
-@defmac EXTRA_CONSTRAINT_STR (@var{value}, @var{c}, @var{str})
-Like @code{EXTRA_CONSTRAINT}, but you also get the constraint string passed
-in @var{str}, so that you can use suffixes to distinguish between different
-variants.
-@end defmac
-
-@defmac EXTRA_MEMORY_CONSTRAINT (@var{c}, @var{str})
-A C expression that defines the optional machine-dependent constraint
-letters, amongst those accepted by @code{EXTRA_CONSTRAINT}, that should
-be treated like memory constraints by the reload pass.
-
-It should return 1 if the operand type represented by the constraint
-at the start of @var{str}, the first letter of which is the letter @var{c},
-comprises a subset of all memory references including
-all those whose address is simply a base register. This allows the reload
-pass to reload an operand, if it does not directly correspond to the operand
-type of @var{c}, by copying its address into a base register.
-
-For example, on the S/390, some instructions do not accept arbitrary
-memory references, but only those that do not make use of an index
-register. The constraint letter @samp{Q} is defined via
-@code{EXTRA_CONSTRAINT} as representing a memory address of this type.
-If the letter @samp{Q} is marked as @code{EXTRA_MEMORY_CONSTRAINT},
-a @samp{Q} constraint can handle any memory operand, because the
-reload pass knows it can be reloaded by copying the memory address
-into a base register if required. This is analogous to the way
-an @samp{o} constraint can handle any memory operand.
-@end defmac
-
-@defmac EXTRA_ADDRESS_CONSTRAINT (@var{c}, @var{str})
-A C expression that defines the optional machine-dependent constraint
-letters, amongst those accepted by @code{EXTRA_CONSTRAINT} /
-@code{EXTRA_CONSTRAINT_STR}, that should
-be treated like address constraints by the reload pass.
-
-It should return 1 if the operand type represented by the constraint
-at the start of @var{str}, which starts with the letter @var{c}, comprises
-a subset of all memory addresses including
-all those that consist of just a base register. This allows the reload
-pass to reload an operand, if it does not directly correspond to the operand
-type of @var{str}, by copying it into a base register.
-
-Any constraint marked as @code{EXTRA_ADDRESS_CONSTRAINT} can only
-be used with the @code{address_operand} predicate. It is treated
-analogously to the @samp{p} constraint.
-@end defmac
+@hook TARGET_CSTORE_MODE
@node Stack and Calling
@section Stack Layout and Calling Conventions
* Profiling::
* Tail Calls::
* Stack Smashing Protection::
+* Miscellaneous Register Hooks::
@end menu
@node Frame Layout
Here is the basic stack layout.
@defmac STACK_GROWS_DOWNWARD
-Define this macro if pushing a word onto the stack moves the stack
-pointer to a smaller address.
-
-When we say, ``define this macro if @dots{}'', it means that the
-compiler checks this macro only with @code{#ifdef} so the precise
-definition used does not matter.
+Define this macro to be true if pushing a word onto the stack moves the stack
+pointer to a smaller address, and false otherwise.
@end defmac
@defmac STACK_PUSH_CODE
space for the next item on the stack.
The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
-defined, which is almost always right, and @code{PRE_INC} otherwise,
+true, which is almost always right, and @code{PRE_INC} otherwise,
which is often wrong.
@end defmac
@end defmac
@hook TARGET_BUILTIN_SETJMP_FRAME_VALUE
-This target hook should return an rtx that is used to store
-the address of the current frame into the built in @code{setjmp} buffer.
-The default value, @code{virtual_stack_vars_rtx}, is correct for most
-machines. One reason you may need to define this target hook is if
-@code{hard_frame_pointer_rtx} is the appropriate value on your machine.
-@end deftypefn
@defmac FRAME_ADDR_RTX (@var{frameaddr})
A C expression whose value is RTL representing the value of the frame
address for the frame @var{count} steps up from the current frame, after
the prologue. @var{frameaddr} is the frame pointer of the @var{count}
frame, or the frame pointer of the @var{count} @minus{} 1 frame if
-@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is defined.
+@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is nonzero.
The value of the expression must always be the correct address when
@var{count} is zero, but may be @code{NULL_RTX} if there is no way to
@end defmac
@defmac RETURN_ADDR_IN_PREVIOUS_FRAME
-Define this if the return address of a particular stack frame is accessed
-from the frame pointer of the previous stack frame.
+Define this macro to nonzero value if the return address of a particular
+stack frame is accessed from the frame pointer of the previous stack
+frame. The zero default for this macro is suitable for most ports.
@end defmac
@defmac INCOMING_RETURN_ADDR_RTX
@end defmac
@hook TARGET_DWARF_HANDLE_FRAME_UNSPEC
-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 [@dots{}] UNSPEC_INDEX))
-@end smallexample
-and
-@smallexample
-(set (reg) (unspec_volatile [@dots{}] 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,
@end defmac
@hook TARGET_STATIC_CHAIN
-This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for
-targets that may use different static chain locations for different
-nested functions. This may be required if the target has function
-attributes that affect the calling conventions of the function and
-those calling conventions use different static chain locations.
-
-The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.
-
-If the static chain is passed in memory, this hook should be used to
-provide rtx giving @code{mem} expressions that denote where they are stored.
-Often the @code{mem} expression as seen by the caller will be at an offset
-from the stack pointer and the @code{mem} expression as seen by the callee
-will be at an offset from the frame pointer.
-@findex stack_pointer_rtx
-@findex frame_pointer_rtx
-@findex arg_pointer_rtx
-The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and
-@code{arg_pointer_rtx} will have been initialized and should be used
-to refer to those items.
-@end deftypefn
@defmac DWARF_FRAME_REGISTERS
This macro specifies the maximum number of hard registers that can be
This is about eliminating the frame pointer and arg pointer.
@hook TARGET_FRAME_POINTER_REQUIRED
-This target hook should return @code{true} if a function must have and use
-a frame pointer. This target hook is called in the reload pass. If its return
-value is @code{true} the function will have a frame pointer.
-
-This target hook can in principle examine the current function and decide
-according to the facts, but on most machines the constant @code{false} or the
-constant @code{true} suffices. Use @code{false} when the machine allows code
-to be generated with no frame pointer, and doing so saves some time or space.
-Use @code{true} when there is no possible advantage to avoiding a frame
-pointer.
-
-In certain cases, the compiler does not know how to produce valid code
-without a frame pointer. The compiler recognizes those cases and
-automatically gives the function a frame pointer regardless of what
-@code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about
-them.
-
-In a function that does not require a frame pointer, the frame pointer
-register can be allocated for ordinary usage, unless you mark it as a
-fixed register. See @code{FIXED_REGISTERS} for more information.
-
-Default return value is @code{false}.
-@end deftypefn
@findex get_frame_size
@defmac INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
@end defmac
@hook TARGET_CAN_ELIMINATE
-This target hook should returns @code{true} if the compiler is allowed to
-try to replace register number @var{from_reg} with register number
-@var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}
-is defined, and will usually be @code{true}, since most of the cases
-preventing register elimination are things that the compiler already
-knows about.
-
-Default return value is @code{true}.
-@end deftypefn
@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
This macro is similar to @code{INITIAL_FRAME_POINTER_OFFSET}. It
control passing certain arguments in registers.
@hook TARGET_PROMOTE_PROTOTYPES
-This target hook returns @code{true} if an argument declared in a
-prototype as an integral type smaller than @code{int} should actually be
-passed as an @code{int}. In addition to avoiding errors in certain
-cases of mismatch, it also makes for better code on certain machines.
-The default is to not promote prototypes.
-@end deftypefn
@defmac PUSH_ARGS
A C expression. If nonzero, push insns will be used to pass
@c above is overfull. not sure what to do. --mew 5feb93 did
@c something, not sure if it looks good. --mew 10feb93
+@defmac INCOMING_REG_PARM_STACK_SPACE (@var{fndecl})
+Like @code{REG_PARM_STACK_SPACE}, but for incoming register arguments.
+Define this macro if space guaranteed when compiling a function body
+is different to space required when making a call, a situation that
+can arise with K&R style function definitions.
+@end defmac
+
@defmac OUTGOING_REG_PARM_STACK_SPACE (@var{fntype})
Define this to a nonzero value if it is the responsibility of the
caller to allocate the area reserved for arguments passed in registers
@end defmac
@hook TARGET_RETURN_POPS_ARGS
-This target hook returns the number of bytes of its own arguments that
-a function pops on returning, or 0 if the function pops no arguments
-and the caller must therefore pop them all after the function returns.
-
-@var{fundecl} is a C variable whose value is a tree node that describes
-the function in question. Normally it is a node of type
-@code{FUNCTION_DECL} that describes the declaration of the function.
-From this you can obtain the @code{DECL_ATTRIBUTES} of the function.
-
-@var{funtype} is a C variable whose value is a tree node that
-describes the function in question. Normally it is a node of type
-@code{FUNCTION_TYPE} that describes the data type of the function.
-From this it is possible to obtain the data types of the value and
-arguments (if known).
-
-When a call to a library function is being considered, @var{fundecl}
-will contain an identifier node for the library function. Thus, if
-you need to distinguish among various library functions, you can do so
-by their names. Note that ``library function'' in this context means
-a function used to perform arithmetic, whose name is known specially
-in the compiler and was not mentioned in the C code being compiled.
-
-@var{size} is the number of bytes of arguments passed on the
-stack. If a variable number of bytes is passed, it is zero, and
-argument popping will always be the responsibility of the calling function.
-
-On the VAX, all functions always pop their arguments, so the definition
-of this macro is @var{size}. On the 68000, using the standard
-calling convention, no functions pop their arguments, so the value of
-the macro is always 0 in this case. But an alternative calling
-convention is available in which functions that take a fixed number of
-arguments pop them but other functions (such as @code{printf}) pop
-nothing (the caller pops all). When this convention is in use,
-@var{funtype} is examined to determine whether a function takes a fixed
-number of arguments.
-@end deftypefn
@defmac CALL_POPS_ARGS (@var{cum})
A C expression that should indicate the number of bytes a call sequence
the stack.
@hook TARGET_FUNCTION_ARG
-Return an RTX indicating whether a function argument is passed in a
-register and if so, which register.
-
-The arguments are @var{ca}, which summarizes all the previous
-arguments; @var{mode}, the machine mode of the argument; @var{type},
-the data type of the argument as a tree node or 0 if that is not known
-(which happens for C support library functions); and @var{named},
-which is @code{true} for an ordinary argument and @code{false} for
-nameless arguments that correspond to @samp{@dots{}} in the called
-function's prototype. @var{type} can be an incomplete type if a
-syntax error has previously occurred.
-
-The return value is usually either a @code{reg} RTX for the hard
-register in which to pass the argument, or zero to pass the argument
-on the stack.
-
-The value of the expression can also be a @code{parallel} RTX@. This is
-used when an argument is passed in multiple locations. The mode of the
-@code{parallel} should be the mode of the entire argument. The
-@code{parallel} holds any number of @code{expr_list} pairs; each one
-describes where part of the argument is passed. In each
-@code{expr_list} the first operand must be a @code{reg} RTX for the hard
-register in which to pass this part of the argument, and the mode of the
-register RTX indicates how large this part of the argument is. The
-second operand of the @code{expr_list} is a @code{const_int} which gives
-the offset in bytes into the entire argument of where this part starts.
-As a special exception the first @code{expr_list} in the @code{parallel}
-RTX may have a first operand of zero. This indicates that the entire
-argument is also stored on the stack.
-
-The last time this hook is called, it is called with @code{MODE ==
-VOIDmode}, and its result is passed to the @code{call} or @code{call_value}
-pattern as operands 2 and 3 respectively.
-
-@cindex @file{stdarg.h} and register arguments
-The usual way to make the ISO library @file{stdarg.h} work on a
-machine where some arguments are usually passed in registers, is to
-cause nameless arguments to be passed on the stack instead. This is
-done by making @code{TARGET_FUNCTION_ARG} return 0 whenever
-@var{named} is @code{false}.
-
-@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}
-@cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}
-You may use the hook @code{targetm.calls.must_pass_in_stack}
-in the definition of this macro to determine if this argument is of a
-type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}
-is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an
-argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is
-defined, the argument will be computed in the stack and then loaded into
-a register.
-@end deftypefn
@hook TARGET_MUST_PASS_IN_STACK
-This target hook should return @code{true} if we should not pass @var{type}
-solely in registers. The file @file{expr.h} defines a
-definition that is usually appropriate, refer to @file{expr.h} for additional
-documentation.
-@end deftypefn
@hook TARGET_FUNCTION_INCOMING_ARG
-Define this hook if the target machine has ``register windows'', so
-that the register in which a function sees an arguments is not
-necessarily the same as the one in which the caller passed the
-argument.
-
-For such machines, @code{TARGET_FUNCTION_ARG} computes the register in
-which the caller passes the value, and
-@code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar
-fashion to tell the function being called where the arguments will
-arrive.
-
-If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,
-@code{TARGET_FUNCTION_ARG} serves both purposes.
-@end deftypefn
+
+@hook TARGET_USE_PSEUDO_PIC_REG
+
+@hook TARGET_INIT_PIC_REG
@hook TARGET_ARG_PARTIAL_BYTES
-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 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 bytes should go in registers.
-
-@code{TARGET_FUNCTION_ARG} for these arguments should return the first
-register to be used by the caller for this argument; likewise
-@code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.
-@end deftypefn
@hook TARGET_PASS_BY_REFERENCE
-This target hook should return @code{true} if an argument at the
-position indicated by @var{cum} should be passed by reference. This
-predicate is queried after target independent reasons for being
-passed by reference, such as @code{TREE_ADDRESSABLE (type)}.
-
-If the hook returns true, a copy of that argument is made in memory and a
-pointer to the argument is passed instead of the argument itself.
-The pointer is passed in whatever way is appropriate for passing a pointer
-to that type.
-@end deftypefn
@hook TARGET_CALLEE_COPIES
-The function argument described by the parameters to this hook is
-known to be passed by reference. The hook should return true if the
-function argument should be copied by the callee instead of copied
-by the caller.
-
-For any argument for which the hook returns true, if it can be
-determined that the argument is not modified, then a copy need
-not be generated.
-
-The default version of this hook always returns false.
-@end deftypefn
@defmac CUMULATIVE_ARGS
A C type for declaring a variable that is used as the first argument
@end defmac
@hook TARGET_FUNCTION_ARG_ADVANCE
-This hook updates the summarizer variable pointed to by @var{ca} to
-advance past an argument in the argument list. The values @var{mode},
-@var{type} and @var{named} describe that argument. Once this is done,
-the variable @var{cum} is suitable for analyzing the @emph{following}
-argument with @code{TARGET_FUNCTION_ARG}, etc.
-
-This hook need not do anything if the argument in question was passed
-on the stack. The compiler knows how to track the amount of stack space
-used for arguments without any special help.
-@end deftypefn
@defmac FUNCTION_ARG_OFFSET (@var{mode}, @var{type})
If defined, a C expression that is the number of bytes to add to the
@end defmac
@hook TARGET_FUNCTION_ARG_BOUNDARY
-This hook returns the alignment boundary, in bits, of an argument
-with the specified mode and type. The default hook returns
-@code{PARM_BOUNDARY} for all arguments.
-@end deftypefn
@hook TARGET_FUNCTION_ARG_ROUND_BOUNDARY
@end defmac
@hook TARGET_SPLIT_COMPLEX_ARG
-This hook should return true if parameter of type @var{type} are passed
-as two scalar parameters. By default, GCC will attempt to pack complex
-arguments into the target's word size. Some ABIs require complex arguments
-to be split and treated as their individual components. For example, on
-AIX64, complex floats should be passed in a pair of floating point
-registers, even though a complex float would fit in one 64-bit floating
-point register.
-
-The default value of this hook is @code{NULL}, which is treated as always
-false.
-@end deftypefn
@hook TARGET_BUILD_BUILTIN_VA_LIST
-This hook returns a type node for @code{va_list} for the target.
-The default version of the hook returns @code{void*}.
-@end deftypefn
@hook TARGET_ENUM_VA_LIST_P
-This target hook is used in function @code{c_common_nodes_and_builtins}
-to iterate through the target specific builtin types for va_list. The
-variable @var{idx} is used as iterator. @var{pname} has to be a pointer
-to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed
-variable.
-The arguments @var{pname} and @var{ptree} are used to store the result of
-this macro and are set to the name of the va_list builtin type and its
-internal type.
-If the return value of this macro is zero, then there is no more element.
-Otherwise the @var{IDX} should be increased for the next call of this
-macro to iterate through all types.
-@end deftypefn
@hook TARGET_FN_ABI_VA_LIST
-This hook returns the va_list type of the calling convention specified by
-@var{fndecl}.
-The default version of this hook returns @code{va_list_type_node}.
-@end deftypefn
@hook TARGET_CANONICAL_VA_LIST_TYPE
-This hook returns the va_list type of the calling convention specified by the
-type of @var{type}. If @var{type} is not a valid va_list type, it returns
-@code{NULL_TREE}.
-@end deftypefn
@hook TARGET_GIMPLIFY_VA_ARG_EXPR
-This hook performs target-specific gimplification of
-@code{VA_ARG_EXPR}. The first two parameters correspond to the
-arguments to @code{va_arg}; the latter two are as in
-@code{gimplify.c:gimplify_expr}.
-@end deftypefn
@hook TARGET_VALID_POINTER_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
@hook TARGET_REF_MAY_ALIAS_ERRNO
@hook TARGET_SCALAR_MODE_SUPPORTED_P
-Define this to return nonzero if the port is prepared to handle
-insns involving scalar mode @var{mode}. For a scalar mode to be
-considered supported, all the basic arithmetic and comparisons
-must work.
-
-The default version of this hook returns true for any mode
-required to handle the basic C types (as defined by the port).
-Included here are the double-word arithmetic supported by the
-code in @file{optabs.c}.
-@end deftypefn
@hook TARGET_VECTOR_MODE_SUPPORTED_P
-Define this to return nonzero if the port is prepared to handle
-insns involving vector mode @var{mode}. At the very least, it
-must have move patterns for this mode.
-@end deftypefn
@hook TARGET_ARRAY_MODE_SUPPORTED_P
-@hook TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
-Define this to return nonzero for machine modes for which the port has
-small register classes. If this target hook returns nonzero for a given
-@var{mode}, the compiler will try to minimize the lifetime of registers
-in @var{mode}. The hook may be called with @code{VOIDmode} as argument.
-In this case, the hook is expected to return nonzero if it returns nonzero
-for any mode.
-
-On some machines, it is risky to let hard registers live across arbitrary
-insns. Typically, these machines have instructions that require values
-to be in specific registers (like an accumulator), and reload will fail
-if the required hard register is used for another purpose across such an
-insn.
-
-Passes before reload do not know which hard registers will be used
-in an instruction, but the machine modes of the registers set or used in
-the instruction are already known. And for some machines, register
-classes are small for, say, integer registers but not for floating point
-registers. For example, the AMD x86-64 architecture requires specific
-registers for the legacy x86 integer instructions, but there are many
-SSE registers for floating point operations. On such targets, a good
-strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}
-machine modes but zero for the SSE register classes.
-
-The default version of this hook returns false for any mode. It is always
-safe to redefine this hook to return with a nonzero value. But if you
-unnecessarily define it, you will reduce the amount of optimizations
-that can be performed in some cases. If you do not define this hook
-to return a nonzero value when it is required, the compiler will run out
-of spill registers and print a fatal error message.
-@end deftypefn
+@hook TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P
-@hook TARGET_FLAGS_REGNUM
+@hook TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
@node Scalar Return
@subsection How Scalar Function Values Are Returned
@hook TARGET_FUNCTION_VALUE
-Define this to return an RTX representing the place where a function
-returns or receives a value of data type @var{ret_type}, a tree node
-representing a data type. @var{fn_decl_or_type} is a tree node
-representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a
-function being called. If @var{outgoing} is false, the hook should
-compute the register in which the caller will see the return value.
-Otherwise, the hook should return an RTX representing the place where
-a function returns a value.
-
-On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.
-(Actually, on most machines, scalar values are returned in the same
-place regardless of mode.) The value of the expression is usually a
-@code{reg} RTX for the hard register where the return value is stored.
-The value can also be a @code{parallel} RTX, if the return value is in
-multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the
-@code{parallel} form. Note that the callee will populate every
-location specified in the @code{parallel}, but if the first element of
-the @code{parallel} contains the whole return value, callers will use
-that element as the canonical location and ignore the others. The m68k
-port uses this type of @code{parallel} to return pointers in both
-@samp{%a0} (the canonical location) and @samp{%d0}.
-
-If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply
-the same promotion rules specified in @code{PROMOTE_MODE} if
-@var{valtype} is a scalar type.
-
-If the precise function being called is known, @var{func} is a tree
-node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
-pointer. This makes it possible to use a different value-returning
-convention for specific functions when all their calls are
-known.
-
-Some target machines have ``register windows'' so that the register in
-which a function returns its value is not the same as the one in which
-the caller sees the value. For such machines, you should return
-different RTX depending on @var{outgoing}.
-
-@code{TARGET_FUNCTION_VALUE} is not used for return values with
-aggregate data types, because these are returned in another way. See
-@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.
-@end deftypefn
-
@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
a new target instead.
@end defmac
@hook TARGET_LIBCALL_VALUE
-Define this hook if the back-end needs to know the name of the libcall
-function in order to determine where the result should be returned.
-
-The mode of the result is given by @var{mode} and the name of the called
-library function is given by @var{fun}. The hook should return an RTX
-representing the place where the library function result will be returned.
-
-If this hook is not defined, then LIBCALL_VALUE will be used.
-@end deftypefn
@defmac FUNCTION_VALUE_REGNO_P (@var{regno})
A C expression that is nonzero if @var{regno} is the number of a hard
@end defmac
@hook TARGET_FUNCTION_VALUE_REGNO_P
-A target hook that return @code{true} if @var{regno} is the number of a hard
-register in which the values of called function may come back.
-
-A register whose use for returning values is limited to serving as the
-second of a pair (for a value of type @code{double}, say) need not be
-recognized by this target hook.
-
-If the machine has register windows, so that the caller and the called
-function use different registers for the return value, this target hook
-should recognize only the caller's register numbers.
-
-If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.
-@end deftypefn
@defmac APPLY_RESULT_SIZE
Define this macro if @samp{untyped_call} and @samp{untyped_return}
saving and restoring an arbitrary return value.
@end defmac
+@hook TARGET_OMIT_STRUCT_RETURN_REG
+
@hook TARGET_RETURN_IN_MSB
-This hook should return true if values of type @var{type} are returned
-at the most significant end of a register (in other words, if they are
-padded at the least significant end). You can assume that @var{type}
-is returned in a register; the caller is required to check this.
-
-Note that the register provided by @code{TARGET_FUNCTION_VALUE} must
-be able to hold the complete return value. For example, if a 1-, 2-
-or 3-byte structure is returned at the most significant end of a
-4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an
-@code{SImode} rtx.
-@end deftypefn
@node Aggregate Return
@subsection How Large Values Are Returned
memory.
@hook TARGET_RETURN_IN_MEMORY
-This target hook should return a nonzero value to say to return the
-function value in memory, just as large structures are always returned.
-Here @var{type} will be the data type of the value, and @var{fntype}
-will be the type of the function doing the returning, or @code{NULL} for
-libcalls.
-
-Note that values of mode @code{BLKmode} must be explicitly handled
-by this function. Also, the option @option{-fpcc-struct-return}
-takes effect regardless of this macro. On most systems, it is
-possible to leave the hook undefined; this causes a default
-definition to be used, whose value is the constant 1 for @code{BLKmode}
-values, and 0 otherwise.
-
-Do not use this hook to indicate that structures and unions should always
-be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}
-to indicate this.
-@end deftypefn
@defmac DEFAULT_PCC_STRUCT_RETURN
Define this macro to be 1 if all structure and union return values must be
@end defmac
@hook TARGET_STRUCT_VALUE_RTX
-This target hook should return the location of the structure value
-address (normally a @code{mem} or @code{reg}), or 0 if the address is
-passed as an ``invisible'' first argument. Note that @var{fndecl} may
-be @code{NULL}, for libcalls. You do not need to define this target
-hook if the address is always passed as an ``invisible'' first
-argument.
-
-On some architectures the place where the structure value address
-is found by the called function is not the same place that the
-caller put it. This can be due to register windows, or it could
-be because the function prologue moves it to a different place.
-@var{incoming} is @code{1} or @code{2} when the location is needed in
-the context of the called function, and @code{0} in the context of
-the caller.
-
-If @var{incoming} is nonzero and the address is to be found on the
-stack, return a @code{mem} which refers to the frame pointer. If
-@var{incoming} is @code{2}, the result is being used to fetch the
-structure value address at the beginning of a function. If you need
-to emit adjusting code, you should do it at this point.
-@end deftypefn
@defmac PCC_STATIC_STRUCT_RETURN
Define this macro if the usual system convention on the target machine
makes it possible to use call-clobbered registers to hold variables that
must live across calls.
-@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
-A C expression to determine whether it is worthwhile to consider placing
-a pseudo-register in a call-clobbered hard register and saving and
-restoring it around each function call. The expression should be 1 when
-this is worth doing, and 0 otherwise.
-
-If you don't define this macro, a default is used which is good on most
-machines: @code{4 * @var{calls} < @var{refs}}.
-@end defmac
-
@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
A C expression specifying which mode is required for saving @var{nregs}
of a pseudo-register in call-clobbered hard register @var{regno}. If
(@dfn{prologue}) and exit (@dfn{epilogue}) code.
@hook TARGET_ASM_FUNCTION_PROLOGUE
-If defined, a function that outputs the assembler code for entry to a
-function. The prologue is responsible for setting up the stack frame,
-initializing the frame pointer register, saving registers that must be
-saved, and allocating @var{size} additional bytes of storage for the
-local variables. @var{size} is an integer. @var{file} is a stdio
-stream to which the assembler code should be output.
-
-The label for the beginning of the function need not be output by this
-macro. That has already been done when the macro is run.
-
-@findex regs_ever_live
-To determine which registers to save, the macro can refer to the array
-@code{regs_ever_live}: element @var{r} is nonzero if hard register
-@var{r} is used anywhere within the function. This implies the function
-prologue should save register @var{r}, provided it is not one of the
-call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use
-@code{regs_ever_live}.)
-
-On machines that have ``register windows'', the function entry code does
-not save on the stack the registers that are in the windows, even if
-they are supposed to be preserved by function calls; instead it takes
-appropriate steps to ``push'' the register stack, if any non-call-used
-registers are used in the function.
-
-@findex frame_pointer_needed
-On machines where functions may or may not have frame-pointers, the
-function entry code must vary accordingly; it must set up the frame
-pointer if one is wanted, and not otherwise. To determine whether a
-frame pointer is in wanted, the macro can refer to the variable
-@code{frame_pointer_needed}. The variable's value will be 1 at run
-time in a function that needs a frame pointer. @xref{Elimination}.
-
-The function entry code is responsible for allocating any stack space
-required for the function. This stack space consists of the regions
-listed below. In most cases, these regions are allocated in the
-order listed, with the last listed region closest to the top of the
-stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and
-the highest address if it is not defined). You can use a different order
-for a machine if doing so is more convenient or required for
-compatibility reasons. Except in cases where required by standard
-or by a debugger, there is no reason why the stack layout used by GCC
-need agree with that used by other compilers for a machine.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_END_PROLOGUE
-If defined, a function that outputs assembler code at the end of a
-prologue. This should be used when the function prologue is being
-emitted as RTL, and you have some extra assembler that needs to be
-emitted. @xref{prologue instruction pattern}.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_BEGIN_EPILOGUE
-If defined, a function that outputs assembler code at the start of an
-epilogue. This should be used when the function epilogue is being
-emitted as RTL, and you have some extra assembler that needs to be
-emitted. @xref{epilogue instruction pattern}.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_EPILOGUE
-If defined, a function that outputs the assembler code for exit from a
-function. The epilogue is responsible for restoring the saved
-registers and stack pointer to their values when the function was
-called, and returning control to the caller. This macro takes the
-same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the
-registers to restore are determined from @code{regs_ever_live} and
-@code{CALL_USED_REGISTERS} in the same way.
-
-On some machines, there is a single instruction that does all the work
-of returning from the function. On these machines, give that
-instruction the name @samp{return} and do not define the macro
-@code{TARGET_ASM_FUNCTION_EPILOGUE} at all.
-
-Do not define a pattern named @samp{return} if you want the
-@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target
-switches to control whether return instructions or epilogues are used,
-define a @samp{return} pattern with a validity condition that tests the
-target switches appropriately. If the @samp{return} pattern's validity
-condition is false, epilogues will be used.
-
-On machines where functions may or may not have frame-pointers, the
-function exit code must vary accordingly. Sometimes the code for these
-two cases is completely different. To determine whether a frame pointer
-is wanted, the macro can refer to the variable
-@code{frame_pointer_needed}. The variable's value will be 1 when compiling
-a function that needs a frame pointer.
-
-Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and
-@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.
-The C variable @code{current_function_is_leaf} is nonzero for such a
-function. @xref{Leaf Functions}.
-
-On some machines, some functions pop their arguments on exit while
-others leave that for the caller to do. For example, the 68020 when
-given @option{-mrtd} pops arguments in functions that take a fixed
-number of arguments.
-
-@findex pops_args
-@findex crtl->args.pops_args
-Your definition of the macro @code{RETURN_POPS_ARGS} decides which
-functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}
-needs to know what was decided. The number of bytes of the current
-function's arguments that this function should pop is available in
-@code{crtl->args.pops_args}. @xref{Scalar Return}.
-@end deftypefn
@itemize @bullet
@item
on entry to an exception edge.
@end defmac
-@defmac DELAY_SLOTS_FOR_EPILOGUE
-Define this macro if the function epilogue contains delay slots to which
-instructions from the rest of the function can be ``moved''. The
-definition should be a C expression whose value is an integer
-representing the number of delay slots there.
-@end defmac
-
-@defmac ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
-A C expression that returns 1 if @var{insn} can be placed in delay
-slot number @var{n} of the epilogue.
-
-The argument @var{n} is an integer which identifies the delay slot now
-being considered (since different slots may have different rules of
-eligibility). It is never negative and is always less than the number
-of epilogue delay slots (what @code{DELAY_SLOTS_FOR_EPILOGUE} returns).
-If you reject a particular insn for a given delay slot, in principle, it
-may be reconsidered for a subsequent delay slot. Also, other insns may
-(at least in principle) be considered for the so far unfilled delay
-slot.
-
-@findex epilogue_delay_list
-@findex crtl->epilogue_delay_list
-@findex final_scan_insn
-The insns accepted to fill the epilogue delay slots are put in an RTL
-list made with @code{insn_list} objects, stored in
-@code{crtl->epilogue_delay_list}. The insn for the first
-delay slot comes first in the list. Your definition of the macro
-@code{TARGET_ASM_FUNCTION_EPILOGUE} should fill the delay slots by
-outputting the insns in this list, usually by calling
-@code{final_scan_insn}.
-
-You need not define this macro if you did not define
-@code{DELAY_SLOTS_FOR_EPILOGUE}.
-@end defmac
-
@hook TARGET_ASM_OUTPUT_MI_THUNK
-A function that outputs the assembler code for a thunk
-function, used to implement C++ virtual function calls with multiple
-inheritance. The thunk acts as a wrapper around a virtual function,
-adjusting the implicit object parameter before handing control off to
-the real function.
-
-First, emit code to add the integer @var{delta} to the location that
-contains the incoming first argument. Assume that this argument
-contains a pointer, and is the one used to pass the @code{this} pointer
-in C++. This is the incoming argument @emph{before} the function prologue,
-e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of
-all other incoming arguments.
-
-Then, if @var{vcall_offset} is nonzero, an additional adjustment should be
-made after adding @code{delta}. In particular, if @var{p} is the
-adjusted pointer, the following adjustment should be made:
-
-@smallexample
-p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]
-@end smallexample
-
-After the additions, emit code to jump to @var{function}, which is a
-@code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does
-not touch the return address. Hence returning from @var{FUNCTION} will
-return to whoever called the current @samp{thunk}.
-
-The effect must be as if @var{function} had been called directly with
-the adjusted first argument. This macro is responsible for emitting all
-of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}
-and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.
-
-The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}
-have already been extracted from it.) It might possibly be useful on
-some targets, but probably not.
-
-If you do not define this macro, the target-independent code in the C++
-front end will generate a less efficient heavyweight thunk that calls
-@var{function} instead of jumping to it. The generic approach does
-not support varargs.
-@end deftypefn
@hook TARGET_ASM_CAN_OUTPUT_MI_THUNK
-A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able
-to output the assembler code for the thunk function specified by the
-arguments it is passed, and false otherwise. In the latter case, the
-generic approach will be used by the C++ front end, with the limitations
-previously exposed.
-@end deftypefn
@node Profiling
@subsection Generating Code for Profiling
the function prologue. Normally, the profiling code comes after.
@end defmac
+@hook TARGET_KEEP_LEAF_WHEN_PROFILED
+
@node Tail Calls
@subsection Permitting tail calls
@cindex tail calls
@hook TARGET_FUNCTION_OK_FOR_SIBCALL
-True if it is ok to do sibling call optimization for the specified
-call expression @var{exp}. @var{decl} will be the called function,
-or @code{NULL} if this is an indirect call.
-
-It is not uncommon for limitations of calling conventions to prevent
-tail calls to functions outside the current unit of translation, or
-during PIC compilation. The hook is used to enforce these restrictions,
-as the @code{sibcall} md pattern can not fail, or fall over to a
-``normal'' call. The criteria for successful sibling call optimization
-may vary greatly between different architectures.
-@end deftypefn
@hook TARGET_EXTRA_LIVE_ON_ENTRY
-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
@hook TARGET_SET_UP_BY_PROLOGUE
@cindex stack smashing protection
@hook TARGET_STACK_PROTECT_GUARD
-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
@hook TARGET_STACK_PROTECT_FAIL
-This hook returns a @code{CALL_EXPR} 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
@hook TARGET_SUPPORTS_SPLIT_STACK
+@node Miscellaneous Register Hooks
+@subsection Miscellaneous register hooks
+@cindex miscellaneous register hooks
+
+@hook TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS
+
@node Varargs
@section Implementing the Varargs Macros
@cindex varargs implementation
These machine description macros help implement varargs:
@hook TARGET_EXPAND_BUILTIN_SAVEREGS
-If defined, this hook produces the machine-specific code for a call to
-@code{__builtin_saveregs}. This code will be moved to the very
-beginning of the function, before any parameter access are made. The
-return value of this function should be an RTX that contains the value
-to use as the return of @code{__builtin_saveregs}.
-@end deftypefn
@hook TARGET_SETUP_INCOMING_VARARGS
-This target hook offers an alternative to using
-@code{__builtin_saveregs} and defining the hook
-@code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous
-register arguments into the stack so that all the arguments appear to
-have been passed consecutively on the stack. Once this is done, you can
-use the standard implementation of varargs that works for machines that
-pass all their arguments on the stack.
-
-The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data
-structure, containing the values that are obtained after processing the
-named arguments. The arguments @var{mode} and @var{type} describe the
-last named argument---its machine mode and its data type as a tree node.
-
-The target hook should do two things: first, push onto the stack all the
-argument registers @emph{not} used for the named arguments, and second,
-store the size of the data thus pushed into the @code{int}-valued
-variable pointed to by @var{pretend_args_size}. The value that you
-store here will serve as additional offset for setting up the stack
-frame.
-
-Because you must generate code to push the anonymous arguments at
-compile time without knowing their data types,
-@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that
-have just a single category of argument register and use it uniformly
-for all data types.
-
-If the argument @var{second_time} is nonzero, it means that the
-arguments of the function are being analyzed for the second time. This
-happens for an inline function, which is not actually compiled until the
-end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should
-not generate any instructions in this case.
-@end deftypefn
@hook TARGET_STRICT_ARGUMENT_NAMING
-Define this hook to return @code{true} if the location where a function
-argument is passed depends on whether or not it is a named argument.
-
-This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}
-is set for varargs and stdarg functions. If this hook returns
-@code{true}, the @var{named} argument is always true for named
-arguments, and false for unnamed arguments. If it returns @code{false},
-but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},
-then all arguments are treated as named. Otherwise, all named arguments
-except the last are treated as named.
-
-You need not define this hook if it always returns @code{false}.
-@end deftypefn
+
+@hook TARGET_CALL_ARGS
+
+@hook TARGET_END_CALL_ARGS
@hook TARGET_PRETEND_OUTGOING_VARARGS_NAMED
-If you need to conditionally change ABIs so that one works with
-@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither
-@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was
-defined, then define this hook to return @code{true} if
-@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.
-Otherwise, you should not define this hook.
-@end deftypefn
+
+@hook TARGET_LOAD_BOUNDS_FOR_ARG
+
+@hook TARGET_STORE_BOUNDS_FOR_ARG
+
+@hook TARGET_LOAD_RETURNED_BOUNDS
+
+@hook TARGET_STORE_RETURNED_BOUNDS
+
+@hook TARGET_CHKP_FUNCTION_VALUE_BOUNDS
+
+@hook TARGET_SETUP_INCOMING_VARARG_BOUNDS
@node Trampolines
@section Trampolines for Nested Functions
separately.
@hook TARGET_ASM_TRAMPOLINE_TEMPLATE
-This hook is called by @code{assemble_trampoline_template} to output,
-on the stream @var{f}, assembler code for a block of data that contains
-the constant parts of a trampoline. This code should not include a
-label---the label is taken care of automatically.
-
-If you do not define this hook, it means no template is needed
-for the target. Do not define this hook on systems where the block move
-code to copy the trampoline into place would be larger than the code
-to generate it on the spot.
-@end deftypefn
@defmac TRAMPOLINE_SECTION
Return the section into which the trampoline template is to be placed
@end defmac
@hook TARGET_TRAMPOLINE_INIT
-This hook is called to initialize a trampoline.
-@var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}
-is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an
-RTX for the static chain value that should be passed to the function
-when it is called.
-
-If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the
-first thing this hook should do is emit a block move into @var{m_tramp}
-from the memory block returned by @code{assemble_trampoline_template}.
-Note that the block move need only cover the constant parts of the
-trampoline. If the target isolates the variable parts of the trampoline
-to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.
-
-If the target requires any other actions, such as flushing caches or
-enabling stack execution, these actions should be performed after
-initializing the trampoline proper.
-@end deftypefn
@hook TARGET_TRAMPOLINE_ADJUST_ADDRESS
-This hook should perform any machine-specific adjustment in
-the address of the trampoline. Its argument contains the address of the
-memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case
-the address to be used for a function call should be different from the
-address at which the template was stored, the different address should
-be returned; otherwise @var{addr} should be returned unchanged.
-If this hook is not defined, @var{addr} will be used for function calls.
-@end deftypefn
Implementing trampolines is difficult on many machines because they have
separate instruction and data caches. Writing into a stack location
@findex set_optab_libfunc
@findex init_one_libfunc
@hook TARGET_INIT_LIBFUNCS
-This hook should declare additional library routines or rename
-existing ones, using the functions @code{set_optab_libfunc} and
-@code{init_one_libfunc} defined in @file{optabs.c}.
-@code{init_optabs} calls this macro after initializing all the normal
-library routines.
-
-The default is to do nothing. Most ports don't need to define this hook.
-@end deftypefn
@hook TARGET_LIBFUNC_GNU_PREFIX
in @file{libgcc.a}, you do not need to define this macro.
@end defmac
+@defmac TARGET_HAS_NO_HW_DIVIDE
+This macro should be defined if the target has no hardware divide
+instructions. If this macro is defined, GCC will use an algorithm which
+make use of simple logical and arithmetic operations for 64-bit
+division. If the macro is not defined, GCC will use an algorithm which
+make use of a 64-bit by 32-bit divide primitive.
+@end defmac
+
@cindex @code{EDOM}, implicit usage
@findex matherr
@defmac TARGET_EDOM
macro, a reasonable default is used.
@end defmac
-@cindex C99 math functions, implicit usage
-@defmac TARGET_C99_FUNCTIONS
-When this macro is nonzero, GCC will implicitly optimize @code{sin} calls into
-@code{sinf} and similarly for other functions defined by C99 standard. The
-default is zero because a number of existing systems lack support for these
-functions in their runtime so this macro needs to be redefined to one on
-systems that do support the C99 runtime.
-@end defmac
-
-@cindex sincos math function, implicit usage
-@defmac TARGET_HAS_SINCOS
-When this macro is nonzero, GCC will implicitly optimize calls to @code{sin}
-and @code{cos} with the same argument to a call to @code{sincos}. The
-default is zero. The target has to provide the following functions:
-@smallexample
-void sincos(double x, double *sin, double *cos);
-void sincosf(float x, float *sin, float *cos);
-void sincosl(long double x, long double *sin, long double *cos);
-@end smallexample
-@end defmac
+@hook TARGET_LIBC_HAS_FUNCTION
@defmac NEXT_OBJC_RUNTIME
Set this macro to 1 to use the "NeXT" Objective-C message sending conventions
@end defmac
@hook TARGET_LEGITIMATE_ADDRESS_P
-A function that returns whether @var{x} (an RTX) is a legitimate memory
-address on the target machine for a memory operand of mode @var{mode}.
-
-Legitimate addresses are defined in two variants: a strict variant and a
-non-strict one. The @var{strict} parameter chooses which variant is
-desired by the caller.
-
-The strict variant is used in the reload pass. It must be defined so
-that any pseudo-register that has not been allocated a hard register is
-considered a memory reference. This is because in contexts where some
-kind of register is required, a pseudo-register with no hard register
-must be rejected. For non-hard registers, the strict variant should look
-up the @code{reg_renumber} array; it should then proceed using the hard
-register number in the array, or treat the pseudo as a memory reference
-if the array holds @code{-1}.
-
-The non-strict variant is used in other passes. It must be defined to
-accept all pseudo-registers in every context where some kind of
-register is required.
-
-Normally, constant addresses which are the sum of a @code{symbol_ref}
-and an integer are stored inside a @code{const} RTX to mark them as
-constant. Therefore, there is no need to recognize such sums
-specifically as legitimate addresses. Normally you would simply
-recognize any @code{const} as legitimate.
-
-Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant
-sums that are not marked with @code{const}. It assumes that a naked
-@code{plus} indicates indexing. If so, then you @emph{must} reject such
-naked constant sums as illegitimate addresses, so that none of them will
-be given to @code{PRINT_OPERAND_ADDRESS}.
-
-@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation
-On some machines, whether a symbolic address is legitimate depends on
-the section that the address refers to. On these machines, define the
-target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information
-into the @code{symbol_ref}, and then check for it here. When you see a
-@code{const}, you will have to look inside it to find the
-@code{symbol_ref} in order to determine the section. @xref{Assembler
-Format}.
-
-@cindex @code{GO_IF_LEGITIMATE_ADDRESS}
-Some ports are still using a deprecated legacy substitute for
-this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro
-has this syntax:
-
-@example
-#define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
-@end example
-
-@noindent
-and should @code{goto @var{label}} if the address @var{x} is a valid
-address on the target machine for a memory operand of mode @var{mode}.
-
-@findex REG_OK_STRICT
-Compiler source files that want to use the strict variant of this
-macro define the macro @code{REG_OK_STRICT}. You should use an
-@code{#ifdef REG_OK_STRICT} conditional to define the strict variant in
-that case and the non-strict variant otherwise.
-
-Using the hook is usually simpler because it limits the number of
-files that are recompiled when changes are made.
-@end deftypefn
@defmac TARGET_MEM_CONSTRAINT
A single character to be used instead of the default @code{'m'}
@end defmac
@hook TARGET_LEGITIMIZE_ADDRESS
-This hook is given an invalid memory address @var{x} for an
-operand of mode @var{mode} and should try to return a valid memory
-address.
-
-@findex break_out_memory_refs
-@var{x} will always be the result of a call to @code{break_out_memory_refs},
-and @var{oldx} will be the operand that was given to that function to produce
-@var{x}.
-
-The code of the hook should not alter the substructure of
-@var{x}. If it transforms @var{x} into a more legitimate form, it
-should return the new @var{x}.
-
-It is not necessary for this hook to come up with a legitimate address,
-with the exception of native TLS addresses (@pxref{Emulated TLS}).
-The compiler has standard ways of doing so in all cases. In fact, if
-the target supports only emulated TLS, it
-is safe to omit this hook or make it return @var{x} if it cannot find
-a valid way to legitimize the address. But often a machine-dependent
-strategy can generate better code.
-@end deftypefn
@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
A C compound statement that attempts to replace @var{x}, which is an address
@end defmac
@hook TARGET_MODE_DEPENDENT_ADDRESS_P
-This hook returns @code{true} if memory address @var{addr} in address
-space @var{addrspace} can have
-different meanings depending on the machine mode of the memory
-reference it is used for or if the address is valid for some modes
-but not others.
-
-Autoincrement and autodecrement addresses typically have mode-dependent
-effects because the amount of the increment or decrement is the size
-of the operand being addressed. Some machines have other mode-dependent
-addresses. Many RISC machines have no mode-dependent addresses.
-
-You may assume that @var{addr} is a valid address for the machine.
-
-The default version of this hook returns @code{false}.
-@end deftypefn
@hook TARGET_LEGITIMATE_CONSTANT_P
-This hook returns true if @var{x} is a legitimate constant for a
-@var{mode}-mode immediate operand on the target machine. You can assume that
-@var{x} satisfies @code{CONSTANT_P}, so you need not check this.
-
-The default definition returns true.
-@end deftypefn
@hook TARGET_DELEGITIMIZE_ADDRESS
-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
@hook TARGET_CONST_NOT_OK_FOR_DEBUG_P
-This hook should return true if @var{x} should not be emitted into
-debug sections.
-@end deftypefn
@hook TARGET_CANNOT_FORCE_CONST_MEM
-This hook should return true if @var{x} is of a form that cannot (or
-should not) be spilled to the constant pool. @var{mode} is the mode
-of @var{x}.
-
-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
@hook TARGET_USE_BLOCKS_FOR_CONSTANT_P
-This hook should return true if pool entries for constant @var{x} can
-be placed in an @code{object_block} structure. @var{mode} is the mode
-of @var{x}.
-The default version returns false for all constants.
-@end deftypefn
+@hook TARGET_USE_BLOCKS_FOR_DECL_P
@hook TARGET_BUILTIN_RECIPROCAL
-This hook should return the DECL of a function that implements reciprocal of
-the builtin function with builtin function code @var{fn}, or
-@code{NULL_TREE} if such a function is not available. @var{md_fn} is true
-when @var{fn} is a code of a machine-dependent builtin function. When
-@var{sqrt} is true, additional optimizations that apply only to the reciprocal
-of a square root function are performed, and only reciprocals of @code{sqrt}
-function are valid.
-@end deftypefn
@hook TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD
-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 autovectorizer, 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}) @minus{} 1 bits of @var{addr} will be considered.
-@end deftypefn
@hook TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST
-Returns cost of different scalar or vector statements for vectorization cost model.
-For vector memory operations the cost may depend on type (@var{vectype}) and
-misalignment value (@var{misalign}).
-@end deftypefn
@hook TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE
-Return true if vector alignment is reachable (by peeling N iterations) for the given type.
-@end deftypefn
@hook TARGET_VECTORIZE_VEC_PERM_CONST_OK
-Return true if a vector created for @code{vec_perm_const} is valid.
-@end deftypefn
@hook TARGET_VECTORIZE_BUILTIN_CONVERSION
-This hook should return the DECL of a function that implements conversion of the
-input vector of type @var{src_type} to type @var{dest_type}.
-The value of @var{code} is one of the enumerators in @code{enum tree_code} and
-specifies how the conversion is to be applied
-(truncation, rounding, etc.).
-
-If this hook is defined, the autovectorizer will use the
-@code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing
-conversion. Otherwise, it will return @code{NULL_TREE}.
-@end deftypefn
@hook TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION
-This hook should return the decl of a function that implements the
-vectorized variant of the builtin function with builtin function code
-@var{code} or @code{NULL_TREE} if such a function is not available.
-The value of @var{fndecl} is the builtin function declaration. The
-return type of the vectorized function shall be of vector type
-@var{vec_type_out} and the argument types should be @var{vec_type_in}.
-@end deftypefn
@hook TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT
-This hook should return true if the target supports misaligned vector
-store/load of a specific factor denoted in the @var{misalignment}
-parameter. The vector store/load should be of machine mode @var{mode} and
-the elements in the vectors should be of type @var{type}. @var{is_packed}
-parameter is true if the memory access is defined in a packed struct.
-@end deftypefn
@hook TARGET_VECTORIZE_PREFERRED_SIMD_MODE
-This hook should return the preferred mode for vectorizing scalar
-mode @var{mode}. The default is
-equal to @code{word_mode}, because the vectorizer can do some
-transformations even in absence of specialized @acronym{SIMD} hardware.
-@end deftypefn
@hook TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES
-This hook should return a mask of sizes that should be iterated over
-after trying to autovectorize using the vector size derived from the
-mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.
-The default is zero which means to not iterate over other vector sizes.
-@end deftypefn
@hook TARGET_VECTORIZE_INIT_COST
@hook TARGET_VECTORIZE_BUILTIN_TM_STORE
@hook TARGET_VECTORIZE_BUILTIN_GATHER
-Target builtin that implements vector gather operation. @var{mem_vectype}
-is the vector type of the load and @var{index_type} is scalar type of
-the index, scaled by @var{scale}.
-The default is @code{NULL_TREE} which means to not vectorize gather
-loads.
-@end deftypefn
+
+@hook TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN
+
+@hook TARGET_SIMD_CLONE_ADJUST
+
+@hook TARGET_SIMD_CLONE_USABLE
@node Anchored Addresses
@section Anchored Addresses
or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value.
@hook TARGET_MIN_ANCHOR_OFFSET
-The minimum offset that should be applied to a section anchor.
-On most targets, it should be the smallest offset that can be
-applied to a base register while still giving a legitimate address
-for every mode. The default value is 0.
-@end deftypevr
@hook TARGET_MAX_ANCHOR_OFFSET
-Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)
-offset that should be applied to section anchors. The default
-value is 0.
-@end deftypevr
@hook TARGET_ASM_OUTPUT_ANCHOR
-Write the assembly code to define section anchor @var{x}, which is a
-@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.
-The hook is called with the assembly output position set to the beginning
-of @code{SYMBOL_REF_BLOCK (@var{x})}.
-
-If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses
-it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.
-If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition
-is @code{NULL}, which disables the use of section anchors altogether.
-@end deftypefn
@hook TARGET_USE_ANCHORS_FOR_SYMBOL_P
-Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}
-@var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and
-@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.
-
-The default version is correct for most targets, but you might need to
-intercept this hook to handle things like target-specific attributes
-or target-specific sections.
-@end deftypefn
@node Condition Code
@section Condition Code Status
most RISC machines.
The implicit clobbering poses a strong restriction on the placement of
-the definition and use of the condition code, which need to be in adjacent
-insns for machines using @code{(cc0)}. This can prevent important
+the definition and use of the condition code. In the past the definition
+and use were always adjacent. However, recent changes to support trapping
+arithmatic may result in the definition and user being in different blocks.
+Thus, there may be a @code{NOTE_INSN_BASIC_BLOCK} between them. Additionally,
+the definition may be the source of exception handling edges.
+
+These restrictions can prevent important
optimizations on some machines. For example, on the IBM RS/6000, there
is a delay for taken branches unless the condition code register is set
three instructions earlier than the conditional branch. The instruction
@menu
* CC0 Condition Codes:: Old style representation of condition codes.
* MODE_CC Condition Codes:: Modern representation of condition codes.
-* Cond Exec Macros:: Macros to control conditional execution.
@end menu
@node CC0 Condition Codes
@smallexample
#define SELECT_CC_MODE(OP,X,Y) \
- (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \
- ? ((OP == EQ || OP == NE) ? CCFPmode : CCFPEmode) \
- : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \
- || GET_CODE (X) == NEG) \
+ (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \
+ ? ((OP == LT || OP == LE || OP == GT || OP == GE) \
+ ? CCFPEmode : CCFPmode) \
+ : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \
+ || GET_CODE (X) == NEG || GET_CODE (x) == ASHIFT) \
? CC_NOOVmode : CCmode))
@end smallexample
in @file{@var{machine}-modes.def}.
@end defmac
-@defmac CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
-On some machines not all possible comparisons are defined, but you can
-convert an invalid comparison into a valid one. For example, the Alpha
-does not have a @code{GT} comparison, but you can use an @code{LT}
-comparison instead and swap the order of the operands.
-
-On such machines, define this macro to be a C statement to do any
-required conversions. @var{code} is the initial comparison code
-and @var{op0} and @var{op1} are the left and right operands of the
-comparison, respectively. You should modify @var{code}, @var{op0}, and
-@var{op1} as required.
-
-GCC will not assume that the comparison resulting from this macro is
-valid but will see if the resulting insn matches a pattern in the
-@file{md} file.
-
-You need not define this macro if it would never change the comparison
-code or operands.
-@end defmac
+@hook TARGET_CANONICALIZE_COMPARISON
@defmac REVERSIBLE_CC_MODE (@var{mode})
A C expression whose value is one if it is always safe to reverse a
You need not define this macro if it would always returns zero or if the
floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}.
For example, here is the definition used on the SPARC, where floating-point
-inequality comparisons are always given @code{CCFPEmode}:
+inequality comparisons are given either @code{CCFPEmode} or @code{CCFPmode}:
@smallexample
-#define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode)
+#define REVERSIBLE_CC_MODE(MODE) \
+ ((MODE) != CCFPEmode && (MODE) != CCFPmode)
@end smallexample
@end defmac
@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case
machine has some non-standard way how to reverse certain conditionals. For
instance in case all floating point conditions are non-trapping, compiler may
-freely convert unordered compares to ordered one. Then definition may look
+freely convert unordered compares to ordered ones. Then definition may look
like:
@smallexample
@end defmac
@hook TARGET_FIXED_CONDITION_CODE_REGS
-On targets which do not use @code{(cc0)}, and which use a hard
-register rather than a pseudo-register to hold condition codes, the
-regular CSE passes are often not able to identify cases in which the
-hard register is set to a common value. Use this hook to enable a
-small pass which optimizes such cases. This hook should return true
-to enable this pass, and it should set the integers to which its
-arguments point to the hard register numbers used for condition codes.
-When there is only one such register, as is true on most systems, the
-integer pointed to by @var{p2} should be set to
-@code{INVALID_REGNUM}.
-
-The default version of this hook returns false.
-@end deftypefn
@hook TARGET_CC_MODES_COMPATIBLE
-On targets which use multiple condition code modes in class
-@code{MODE_CC}, it is sometimes the case that a comparison can be
-validly done in more than one mode. On such a system, define this
-target hook to take two mode arguments and to return a mode in which
-both comparisons may be validly done. If there is no such mode,
-return @code{VOIDmode}.
-
-The default version of this hook checks whether the modes are the
-same. If they are, it returns that mode. If they are different, it
-returns @code{VOIDmode}.
-@end deftypefn
-@node Cond Exec Macros
-@subsection Macros to control conditional execution
-@findex conditional execution
-@findex predication
-
-There is one macro that may need to be defined for targets
-supporting conditional execution, independent of how they
-represent conditional branches.
+@hook TARGET_FLAGS_REGNUM
@node Costs
@section Describing Relative Costs of Operations
@end defmac
@hook TARGET_REGISTER_MOVE_COST
-This target hook should return the cost of moving data of mode @var{mode}
-from a register in class @var{from} to one in class @var{to}. The classes
-are expressed using the enumeration values such as @code{GENERAL_REGS}.
-A value of 2 is the default; other values are interpreted relative to
-that.
-
-It is not required that the cost always equal 2 when @var{from} is the
-same as @var{to}; on some machines it is expensive to move between
-registers if they are not general registers.
-
-If reload sees an insn consisting of a single @code{set} between two
-hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their
-classes returns a value of 2, reload does not check to ensure that the
-constraints of the insn are met. Setting a cost of other than 2 will
-allow reload to verify that the constraints are met. You should do this
-if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
-
-The default version of this function returns 2.
-@end deftypefn
@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
A C expression for the cost of moving data of mode @var{mode} between a
@end defmac
@hook TARGET_MEMORY_MOVE_COST
-This target hook should return the cost of moving data of mode @var{mode}
-between a register of class @var{rclass} and memory; @var{in} is @code{false}
-if the value is to be written to memory, @code{true} if it is to be read in.
-This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.
-If moving between registers and memory is more expensive than between two
-registers, you should add this target hook to express the relative cost.
-
-If you do not add this target hook, GCC uses a default cost of 4 plus
-the cost of copying via a secondary reload register, if one is
-needed. If your machine requires a secondary reload register to copy
-between memory and a register of @var{rclass} but the reload mechanism is
-more complex than copying via an intermediate, use this target hook to
-reflect the actual cost of the move.
-
-GCC defines the function @code{memory_move_secondary_cost} if
-secondary reloads are needed. It computes the costs due to copying via
-a secondary register. If your machine copies from memory using a
-secondary register in the conventional way but the default base value of
-4 is not correct for your machine, use this target hook to add some other
-value to the result of that function. The arguments to that function
-are the same as to this target hook.
-@end deftypefn
@defmac BRANCH_COST (@var{speed_p}, @var{predictable_p})
A C expression for the cost of a branch instruction. A value of 1 is
If you don't define this, a reasonable default is used.
@end defmac
-@defmac MOVE_BY_PIECES_P (@var{size}, @var{alignment})
-A C expression used to determine whether @code{move_by_pieces} will be used to
-copy a chunk of memory, or whether some other block move mechanism
-will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
-than @code{MOVE_RATIO}.
-@end defmac
+@hook TARGET_USE_BY_PIECES_INFRASTRUCTURE_P
@defmac MOVE_MAX_PIECES
A C expression used by @code{move_by_pieces} to determine the largest unit
If you don't define this, a reasonable default is used.
@end defmac
-@defmac CLEAR_BY_PIECES_P (@var{size}, @var{alignment})
-A C expression used to determine whether @code{clear_by_pieces} will be used
-to clear a chunk of memory, or whether some other block clear mechanism
-will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
-than @code{CLEAR_RATIO}.
-@end defmac
-
@defmac SET_RATIO (@var{speed})
The threshold of number of scalar move insns, @emph{below} which a sequence
of insns should be generated to set memory to a constant value, instead of
If you don't define this, it defaults to the value of @code{MOVE_RATIO}.
@end defmac
-@defmac SET_BY_PIECES_P (@var{size}, @var{alignment})
-A C expression used to determine whether @code{store_by_pieces} will be
-used to set a chunk of memory to a constant value, or whether some
-other mechanism will be used. Used by @code{__builtin_memset} when
-storing values other than constant zero.
-Defaults to 1 if @code{move_by_pieces_ninsns} returns less
-than @code{SET_RATIO}.
-@end defmac
-
-@defmac STORE_BY_PIECES_P (@var{size}, @var{alignment})
-A C expression used to determine whether @code{store_by_pieces} will be
-used to set a chunk of memory to a constant string value, or whether some
-other mechanism will be used. Used by @code{__builtin_strcpy} when
-called with a constant source string.
-Defaults to 1 if @code{move_by_pieces_ninsns} returns less
-than @code{MOVE_RATIO}.
-@end defmac
-
@defmac USE_LOAD_POST_INCREMENT (@var{mode})
A C expression used to determine whether a load postincrement is a good
thing to use for a given mode. Defaults to the value of
@end defmac
@defmac NO_FUNCTION_CSE
-Define this macro if it is as good or better to call a constant
+Define this macro to be true if it is as good or better to call a constant
function address than to call an address kept in a register.
@end defmac
@end defmac
@hook TARGET_RTX_COSTS
-This target hook describes the relative costs of RTL expressions.
-
-The cost may depend on the precise form of the expression, which is
-available for examination in @var{x}, and the fact that @var{x} appears
-as operand @var{opno} of an expression with rtx code @var{outer_code}.
-That is, the hook can assume that there is some rtx @var{y} such
-that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that
-either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or
-(b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.
-
-@var{code} is @var{x}'s expression code---redundant, since it can be
-obtained with @code{GET_CODE (@var{x})}.
-
-In implementing this hook, you can use the construct
-@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
-instructions.
-
-On entry to the hook, @code{*@var{total}} contains a default estimate
-for the cost of the expression. The hook should modify this value as
-necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}
-for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus
-operations, and @code{COSTS_N_INSNS (1)} for all other operations.
-
-When optimizing for code size, i.e.@: when @code{speed} is
-false, this target hook should be used to estimate the relative
-size cost of an expression, again relative to @code{COSTS_N_INSNS}.
-
-The hook returns true when all subexpressions of @var{x} have been
-processed, and false when @code{rtx_cost} should recurse.
-@end deftypefn
@hook TARGET_ADDRESS_COST
-This hook computes the cost of an addressing mode that contains
-@var{address}. If not defined, the cost is computed from
-the @var{address} expression and the @code{TARGET_RTX_COST} hook.
-
-For most CISC machines, the default cost is a good approximation of the
-true cost of the addressing mode. However, on RISC machines, all
-instructions normally have the same length and execution time. Hence
-all addresses will have equal costs.
-
-In cases where more than one form of an address is known, the form with
-the lowest cost will be used. If multiple forms have the same, lowest,
-cost, the one that is the most complex will be used.
-
-For example, suppose an address that is equal to the sum of a register
-and a constant is used twice in the same basic block. When this macro
-is not defined, the address will be computed in a register and memory
-references will be indirect through that register. On machines where
-the cost of the addressing mode containing the sum is no higher than
-that of a simple indirect reference, this will produce an additional
-instruction and possibly require an additional register. Proper
-specification of this macro eliminates this overhead for such machines.
-
-This hook is never called with an invalid address.
-
-On machines where an address involving more than one register is as
-cheap as an address computation involving only one register, defining
-@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to
-be live over a region of code where only one would have been if
-@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect
-should be considered in the definition of this macro. Equivalent costs
-should probably only be given to addresses with different numbers of
-registers on machines with lots of registers.
-@end deftypefn
@node Scheduling
@section Adjusting the Instruction Scheduler
them: try the first ones in this list first.
@hook TARGET_SCHED_ISSUE_RATE
-This hook returns the maximum number of instructions that can ever
-issue at the same time on the target machine. The default is one.
-Although the insn scheduler can define itself the possibility of issue
-an insn on the same cycle, the value can serve as an additional
-constraint to issue insns on the same simulated processor cycle (see
-hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).
-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}.
-@end deftypefn
@hook TARGET_SCHED_VARIABLE_ISSUE
-This hook is executed by the scheduler after it has scheduled an insn
-from the ready list. It should return the number of insns which can
-still be issued in the current cycle. The default is
-@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and
-@code{USE}, which normally are not counted against the issue rate.
-You should define this hook if some insns take more machine resources
-than others, so that fewer insns can follow them in the same cycle.
-@var{file} is either a null pointer, or a stdio stream to write any
-debug output to. @var{verbose} is the verbose level provided by
-@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that
-was scheduled.
-@end deftypefn
@hook TARGET_SCHED_ADJUST_COST
-This function corrects the value of @var{cost} based on the
-relationship between @var{insn} and @var{dep_insn} through the
-dependence @var{link}. It should return the new value. The default
-is to make no adjustment to @var{cost}. This can be used for example
-to specify to the scheduler using the traditional pipeline description
-that an output- or anti-dependence does not incur the same cost as a
-data-dependence. If the scheduler using the automaton based pipeline
-description, the cost of anti-dependence is zero and the cost of
-output-dependence is maximum of one and the difference of latency
-times of the first and the second insns. If these values are not
-acceptable, you could use the hook to modify them too. See also
-@pxref{Processor pipeline description}.
-@end deftypefn
@hook TARGET_SCHED_ADJUST_PRIORITY
-This hook adjusts the integer scheduling priority @var{priority} of
-@var{insn}. It should return the new priority. Increase the priority to
-execute @var{insn} earlier, reduce the priority to execute @var{insn}
-later. Do not define this hook if you do not need to adjust the
-scheduling priorities of insns.
-@end deftypefn
@hook TARGET_SCHED_REORDER
-This hook is executed by the scheduler after it has scheduled the ready
-list, to allow the machine description to reorder it (for example to
-combine two small instructions together on @samp{VLIW} machines).
-@var{file} is either a null pointer, or a stdio stream to write any
-debug output to. @var{verbose} is the verbose level provided by
-@option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready
-list of instructions that are ready to be scheduled. @var{n_readyp} is
-a pointer to the number of elements in the ready list. The scheduler
-reads the ready list in reverse order, starting with
-@var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}
-is the timer tick of the scheduler. You may modify the ready list and
-the number of ready insns. The return value is the number of insns that
-can issue this cycle; normally this is just @code{issue_rate}. See also
-@samp{TARGET_SCHED_REORDER2}.
-@end deftypefn
@hook TARGET_SCHED_REORDER2
-Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That
-function is called whenever the scheduler starts a new cycle. This one
-is called once per iteration over a cycle, immediately after
-@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and
-return the number of insns to be scheduled in the same cycle. Defining
-this hook can be useful if there are frequent situations where
-scheduling one insn causes other insns to become ready in the same
-cycle. These other insns can then be taken into account properly.
-@end deftypefn
+
+@hook TARGET_SCHED_MACRO_FUSION_P
+
+@hook TARGET_SCHED_MACRO_FUSION_PAIR_P
@hook TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
-This hook is called after evaluation forward dependencies of insns in
-chain given by two parameter values (@var{head} and @var{tail}
-correspondingly) but before insns scheduling of the insn chain. For
-example, it can be used for better insn classification if it requires
-analysis of dependencies. This hook can use backward and forward
-dependencies of the insn scheduler because they are already
-calculated.
-@end deftypefn
@hook TARGET_SCHED_INIT
-This hook is executed by the scheduler at the beginning of each block of
-instructions that are to be scheduled. @var{file} is either a null
-pointer, or a stdio stream to write any debug output to. @var{verbose}
-is the verbose level provided by @option{-fsched-verbose-@var{n}}.
-@var{max_ready} is the maximum number of insns in the current scheduling
-region that can be live at the same time. This can be used to allocate
-scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.
-@end deftypefn
@hook TARGET_SCHED_FINISH
-This hook is executed by the scheduler at the end of each block of
-instructions that are to be scheduled. It can be used to perform
-cleanup of any actions done by the other scheduling hooks. @var{file}
-is either a null pointer, or a stdio stream to write any debug output
-to. @var{verbose} is the verbose level provided by
-@option{-fsched-verbose-@var{n}}.
-@end deftypefn
@hook TARGET_SCHED_INIT_GLOBAL
-This hook is executed by the scheduler after function level initializations.
-@var{file} is either a null pointer, or a stdio stream to write any debug output to.
-@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.
-@var{old_max_uid} is the maximum insn uid when scheduling begins.
-@end deftypefn
@hook TARGET_SCHED_FINISH_GLOBAL
-This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.
-@var{file} is either a null pointer, or a stdio stream to write any debug output to.
-@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.
-@end deftypefn
@hook TARGET_SCHED_DFA_PRE_CYCLE_INSN
-The hook returns an RTL insn. The automaton state used in the
-pipeline hazard recognizer is changed as if the insn were scheduled
-when the new simulated processor cycle starts. Usage of the hook may
-simplify the automaton pipeline description for some @acronym{VLIW}
-processors. If the hook is defined, it is used only for the automaton
-based pipeline description. The default is not to change the state
-when the new simulated processor cycle starts.
-@end deftypefn
@hook TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN
-The hook can be used to initialize data used by the previous hook.
-@end deftypefn
@hook TARGET_SCHED_DFA_POST_CYCLE_INSN
-The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used
-to changed the state as if the insn were scheduled when the new
-simulated processor cycle finishes.
-@end deftypefn
@hook TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN
-The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but
-used to initialize data used by the previous hook.
-@end deftypefn
@hook TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE
-The hook to notify target that the current simulated cycle is about to finish.
-The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used
-to change the state in more complicated situations - e.g., when advancing
-state on a single insn is not enough.
-@end deftypefn
@hook TARGET_SCHED_DFA_POST_ADVANCE_CYCLE
-The hook to notify target that new simulated cycle has just started.
-The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used
-to change the state in more complicated situations - e.g., when advancing
-state on a single insn is not enough.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
-This hook controls better choosing an insn from the ready insn queue
-for the @acronym{DFA}-based insn scheduler. Usually the scheduler
-chooses the first insn from the queue. If the hook returns a positive
-value, an additional scheduler code tries all permutations of
-@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}
-subsequent ready insns to choose an insn whose issue will result in
-maximal number of issued insns on the same cycle. For the
-@acronym{VLIW} processor, the code could actually solve the problem of
-packing simple insns into the @acronym{VLIW} insn. Of course, if the
-rules of @acronym{VLIW} packing are described in the automaton.
-
-This code also could be used for superscalar @acronym{RISC}
-processors. Let us consider a superscalar @acronym{RISC} processor
-with 3 pipelines. Some insns can be executed in pipelines @var{A} or
-@var{B}, some insns can be executed only in pipelines @var{B} or
-@var{C}, and one insn can be executed in pipeline @var{B}. The
-processor may issue the 1st insn into @var{A} and the 2nd one into
-@var{B}. In this case, the 3rd insn will wait for freeing @var{B}
-until the next cycle. If the scheduler issues the 3rd insn the first,
-the processor could issue all 3 insns per cycle.
-
-Actually this code demonstrates advantages of the automaton based
-pipeline hazard recognizer. We try quickly and easy many insn
-schedules to choose the best one.
-
-The default is no multipass scheduling.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD
-This hook controls what insns from the ready insn queue will be
-considered for the multipass insn scheduling. If the hook returns
-zero for @var{insn}, the insn will be not chosen to
-be issued.
-
-The default is that any ready insns can be chosen to be issued.
-@end deftypefn
-
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN
-This hook prepares the target backend for a new round of multipass
-scheduling.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE
-This hook is called when multipass scheduling evaluates instruction INSN.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK
-This is called when multipass scheduling backtracks from evaluation of
-an instruction.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END
-This hook notifies the target about the result of the concluded current
-round of multipass scheduling.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT
-This hook initializes target-specific data used in multipass scheduling.
-@end deftypefn
@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI
-This hook finalizes target-specific data used in multipass scheduling.
-@end deftypefn
@hook TARGET_SCHED_DFA_NEW_CYCLE
-This hook is called by the insn scheduler before issuing @var{insn}
-on cycle @var{clock}. If the hook returns nonzero,
-@var{insn} is not issued on this processor cycle. Instead,
-the processor cycle is advanced. If *@var{sort_p}
-is zero, the insn ready queue is not sorted on the new cycle
-start as usually. @var{dump} and @var{verbose} specify the file and
-verbosity level to use for debugging output.
-@var{last_clock} and @var{clock} are, respectively, the
-processor cycle on which the previous insn has been issued,
-and the current processor cycle.
-@end deftypefn
@hook TARGET_SCHED_IS_COSTLY_DEPENDENCE
-This hook is used to define which dependences are considered costly by
-the target, so costly that it is not advisable to schedule the insns that
-are involved in the dependence too close to one another. The parameters
-to this hook are as follows: The first parameter @var{_dep} is the dependence
-being evaluated. The second parameter @var{cost} is the cost of the
-dependence as estimated by the scheduler, and the third
-parameter @var{distance} is the distance in cycles between the two insns.
-The hook returns @code{true} if considering the distance between the two
-insns the dependence between them is considered costly by the target,
-and @code{false} otherwise.
-
-Defining this hook can be useful in multiple-issue out-of-order machines,
-where (a) it's practically hopeless to predict the actual data/resource
-delays, however: (b) there's a better chance to predict the actual grouping
-that will be formed, and (c) correctly emulating the grouping can be very
-important. In such targets one may want to allow issuing dependent insns
-closer to one another---i.e., closer than the dependence distance; however,
-not in cases of ``costly dependences'', which this hooks allows to define.
-@end deftypefn
@hook TARGET_SCHED_H_I_D_EXTENDED
-This hook is called by the insn scheduler after emitting a new instruction to
-the instruction stream. The hook notifies a target backend to extend its
-per instruction data structures.
-@end deftypefn
@hook TARGET_SCHED_ALLOC_SCHED_CONTEXT
-Return a pointer to a store large enough to hold target scheduling context.
-@end deftypefn
@hook TARGET_SCHED_INIT_SCHED_CONTEXT
-Initialize store pointed to by @var{tc} to hold target scheduling context.
-It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the
-beginning of the block. Otherwise, copy the current context into @var{tc}.
-@end deftypefn
@hook TARGET_SCHED_SET_SCHED_CONTEXT
-Copy target scheduling context pointed to by @var{tc} to the current context.
-@end deftypefn
@hook TARGET_SCHED_CLEAR_SCHED_CONTEXT
-Deallocate internal data in target scheduling context pointed to by @var{tc}.
-@end deftypefn
@hook TARGET_SCHED_FREE_SCHED_CONTEXT
-Deallocate a store for target scheduling context pointed to by @var{tc}.
-@end deftypefn
@hook TARGET_SCHED_SPECULATE_INSN
-This hook is called by the insn scheduler when @var{insn} has only
-speculative dependencies and therefore can be scheduled speculatively.
-The hook is used to check if the pattern of @var{insn} has a speculative
-version and, in case of successful check, to generate that speculative
-pattern. The hook should return 1, if the instruction has a speculative form,
-or @minus{}1, if it doesn't. @var{request} describes the type of requested
-speculation. If the return value equals 1 then @var{new_pat} is assigned
-the generated speculative pattern.
-@end deftypefn
@hook TARGET_SCHED_NEEDS_BLOCK_P
-This hook is called by the insn scheduler during generation of recovery code
-for @var{insn}. It should return @code{true}, if the corresponding check
-instruction should branch to recovery code, or @code{false} otherwise.
-@end deftypefn
@hook TARGET_SCHED_GEN_SPEC_CHECK
-This hook is called by the insn scheduler to generate a pattern for recovery
-check instruction. If @var{mutate_p} is zero, then @var{insn} is a
-speculative instruction for which the check should be generated.
-@var{label} is either a label of a basic block, where recovery code should
-be emitted, or a null pointer, when requested check doesn't branch to
-recovery code (a simple check). If @var{mutate_p} is nonzero, then
-a pattern for a branchy check corresponding to a simple check denoted by
-@var{insn} should be generated. In this case @var{label} can't be null.
-@end deftypefn
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC
-This hook is used as a workaround for
-@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD} not being
-called on the first instruction of the ready list. The hook is used to
-discard speculative instructions that stand first in the ready list from
-being scheduled on the current cycle. If the hook returns @code{false},
-@var{insn} will not be chosen to be issued.
-For non-speculative instructions,
-the hook should always return @code{true}. For example, in the ia64 backend
-the hook is used to cancel data speculative insns when the ALAT table
-is nearly full.
-@end deftypefn
@hook TARGET_SCHED_SET_SCHED_FLAGS
-This hook is used by the insn scheduler to find out what features should be
-enabled/used.
-The structure *@var{spec_info} should be filled in by the target.
-The structure describes speculation types that can be used in the scheduler.
-@end deftypefn
@hook TARGET_SCHED_SMS_RES_MII
-This hook is called by the swing modulo scheduler to calculate a
-resource-based lower bound which is based on the resources available in
-the machine and the resources required by each instruction. The target
-backend can use @var{g} to calculate such bound. A very simple lower
-bound will be used in case this hook is not implemented: the total number
-of instructions divided by the issue rate.
-@end deftypefn
@hook TARGET_SCHED_DISPATCH
-This hook is called by Haifa Scheduler. It returns true if dispatch scheduling
-is supported in hardware and the condition specified in the parameter is true.
-@end deftypefn
@hook TARGET_SCHED_DISPATCH_DO
-This hook is called by Haifa Scheduler. It performs the operation specified
-in its second parameter.
-@end deftypefn
@hook TARGET_SCHED_EXPOSED_PIPELINE
@hook TARGET_SCHED_REASSOCIATION_WIDTH
+@hook TARGET_SCHED_FUSION_PRIORITY
+
@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
@end defmac
@hook TARGET_ASM_INIT_SECTIONS
-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
@hook TARGET_ASM_RELOC_RW_MASK
-Return a mask describing how relocations should be treated when
-selecting sections. Bit 1 should be set if global relocations
-should be placed in a read-write section; bit 0 should be set if
-local relocations should be placed in a read-write section.
-
-The default version of this function returns 3 when @option{-fpic}
-is in effect, and 0 otherwise. The hook is typically redefined
-when the target cannot support (some kinds of) dynamic relocations
-in read-only sections even in executables.
-@end deftypefn
@hook TARGET_ASM_SELECT_SECTION
-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.
-@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}.
-
-See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.
-@end deftypefn
@defmac USE_SELECT_SECTION_FOR_FUNCTIONS
Define this macro if you wish TARGET_ASM_SELECT_SECTION to be called
@end defmac
@hook TARGET_ASM_UNIQUE_SECTION
-Build up a unique section name, expressed as a @code{STRING_CST} node,
-and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
-As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether
-the initial value of @var{exp} requires link-time relocations.
-
-The default version of this function appends the symbol name to the
-ELF section name that would normally be used for the symbol. For
-example, the function @code{foo} would be placed in @code{.text.foo}.
-Whatever the actual target object format, this is often good enough.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_RODATA_SECTION
-Return the readonly data section associated with
-@samp{DECL_SECTION_NAME (@var{decl})}.
-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
@hook TARGET_ASM_MERGEABLE_RODATA_PREFIX
@hook TARGET_ASM_TM_CLONE_TABLE_SECTION
@hook TARGET_ASM_SELECT_RTX_SECTION
-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. @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
-else in @code{readonly_data_section}.
-@end deftypefn
@hook TARGET_MANGLE_DECL_ASSEMBLER_NAME
-Define this hook if you need to postprocess the assembler name generated
-by target-independent code. The @var{id} provided to this hook will be
-the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,
-or the mangled name of the @var{decl} in C++). The return value of the
-hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on
-your target system. The default implementation of this hook just
-returns the @var{id} provided.
-@end deftypefn
@hook TARGET_ENCODE_SECTION_INFO
-Define this hook if references to a symbol or a constant must be
-treated differently depending on something about the variable or
-function named by the symbol (such as what section it is in).
-
-The hook is executed immediately after rtl has been created for
-@var{decl}, which may be a variable or function declaration or
-an entry in the constant pool. In either case, @var{rtl} is the
-rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}
-in this hook; that field may not have been initialized yet.
-
-In the case of a constant, it is safe to assume that the rtl is
-a @code{mem} whose address is a @code{symbol_ref}. Most decls
-will also have this form, but that is not guaranteed. Global
-register variables, for instance, will have a @code{reg} for their
-rtl. (Normally the right thing to do with such unusual rtl is
-leave it alone.)
-
-The @var{new_decl_p} argument will be true if this is the first time
-that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will
-be false for subsequent invocations, which will happen for duplicate
-declarations. Whether or not anything must be done for the duplicate
-declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.
-@var{new_decl_p} is always true when the hook is called for a constant.
-
-@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}
-The usual thing for this hook to do is to record flags in the
-@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.
-Historically, the name string was modified if it was necessary to
-encode more than one bit of information, but this practice is now
-discouraged; use @code{SYMBOL_REF_FLAGS}.
-
-The default definition of this hook, @code{default_encode_section_info}
-in @file{varasm.c}, sets a number of commonly-useful bits in
-@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need
-before overriding it.
-@end deftypefn
@hook TARGET_STRIP_NAME_ENCODING
-Decode @var{name} and return the real name part, sans
-the characters that @code{TARGET_ENCODE_SECTION_INFO}
-may have added.
-@end deftypefn
@hook TARGET_IN_SMALL_DATA_P
-Returns true if @var{exp} should be placed into a ``small data'' section.
-The default version of this hook always returns false.
-@end deftypefn
@hook TARGET_HAVE_SRODATA_SECTION
-Contains the value true if the target places read-only
-``small data'' into a separate section. The default value is false.
-@end deftypevr
@hook TARGET_PROFILE_BEFORE_PROLOGUE
@hook TARGET_BINDS_LOCAL_P
-Returns true if @var{exp} names an object for which name resolution
-rules must resolve to the current ``module'' (dynamic shared library
-or executable image).
-
-The default version of this hook implements the name resolution rules
-for ELF, which has a looser model of global name binding than other
-currently supported object file formats.
-@end deftypefn
@hook TARGET_HAVE_TLS
-Contains the value true if the target supports thread-local storage.
-The default value is false.
-@end deftypevr
@node PIC
@findex default_file_start
@hook TARGET_ASM_FILE_START
-Output to @code{asm_out_file} any text which the assembler expects to
-find at the beginning of a file. The default behavior is controlled
-by two flags, documented below. Unless your target's assembler is
-quite unusual, if you override the default, you should call
-@code{default_file_start} at some point in your target hook. This
-lets other target files rely on these variables.
-@end deftypefn
@hook TARGET_ASM_FILE_START_APP_OFF
-If this flag is true, the text of the macro @code{ASM_APP_OFF} will be
-printed as the very first line in the assembly file, unless
-@option{-fverbose-asm} is in effect. (If that macro has been defined
-to the empty string, this variable has no effect.) With the normal
-definition of @code{ASM_APP_OFF}, the effect is to notify the GNU
-assembler that it need not bother stripping comments or extra
-whitespace from its input. This allows it to work a bit faster.
-
-The default is false. You should not set it to true unless you have
-verified that your port does not generate any extra whitespace or
-comments that will cause GAS to issue errors in NO_APP mode.
-@end deftypevr
@hook TARGET_ASM_FILE_START_FILE_DIRECTIVE
-If this flag is true, @code{output_file_directive} will be called
-for the primary source file, immediately after printing
-@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect
-this to be done. The default is false.
-@end deftypevr
@hook TARGET_ASM_FILE_END
-Output to @code{asm_out_file} any text which the assembler expects
-to find at the end of a file. The default is to output nothing.
-@end deftypefn
@deftypefun void file_end_indicate_exec_stack ()
Some systems use a common convention, the @samp{.note.GNU-stack}
@end deftypefun
@hook TARGET_ASM_LTO_START
-Output to @code{asm_out_file} any text which the assembler expects
-to find at the start of an LTO section. The default is to output
-nothing.
-@end deftypefn
@hook TARGET_ASM_LTO_END
-Output to @code{asm_out_file} any text which the assembler expects
-to find at the end of an LTO section. The default is to output
-nothing.
-@end deftypefn
@hook TARGET_ASM_CODE_END
-Output to @code{asm_out_file} any text which is needed before emitting
-unwind info and debug info at the end of a file. Some targets emit
-here PIC setup thunks that cannot be emitted at the end of file,
-because they couldn't have unwind info then. The default is to output
-nothing.
-@end deftypefn
@defmac ASM_COMMENT_START
A C string constant describing how to begin a comment in the target
@end defmac
@hook TARGET_ASM_NAMED_SECTION
-Output assembly directives to switch to section @var{name}. The section
-should have attributes as specified by @var{flags}, which is a bit mask
-of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}
-is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which
-this section is associated.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_SECTION
-Return preferred text (sub)section for function @var{decl}.
-Main purpose of this function is to separate cold, normal and hot
-functions. @var{startup} is true when function is known to be used only
-at startup (from static constructors or it is @code{main()}).
-@var{exit} is true when function is known to be used only at exit
-(from static destructors).
-Return NULL if function should go to default text section.
-@end deftypefn
@hook TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS
@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}
@hook TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
-This flag is true if we can create zeroed data by switching to a BSS
-section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.
-This is true on most ELF targets.
-@end deftypevr
@hook TARGET_SECTION_TYPE_FLAGS
-Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}
-based on a variable or function decl, a section name, and whether or not the
-declaration's initializer may contain runtime relocations. @var{decl} may be
-null, in which case read-write data should be assumed.
-
-The default version of this function handles choosing code vs data,
-read-only vs read-write data, and @code{flag_pic}. You should only
-need to override this if your target has special flags that might be
-set via @code{__attribute__}.
-@end deftypefn
@hook TARGET_ASM_RECORD_GCC_SWITCHES
-Provides the target with the ability to record the gcc command line
-switches that have been passed to the compiler, and options that are
-enabled. The @var{type} argument specifies what is being recorded.
-It can take the following values:
-
-@table @gcctabopt
-@item SWITCH_TYPE_PASSED
-@var{text} is a command line switch that has been set by the user.
-
-@item SWITCH_TYPE_ENABLED
-@var{text} is an option which has been enabled. This might be as a
-direct result of a command line switch, or because it is enabled by
-default or because it has been enabled as a side effect of a different
-command line switch. For example, the @option{-O2} switch enables
-various different individual optimization passes.
-
-@item SWITCH_TYPE_DESCRIPTIVE
-@var{text} is either NULL or some descriptive text which should be
-ignored. If @var{text} is NULL then it is being used to warn the
-target hook that either recording is starting or ending. The first
-time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the
-warning is for start up and the second time the warning is for
-wind down. This feature is to allow the target hook to make any
-necessary preparations before it starts to record switches and to
-perform any necessary tidying up after it has finished recording
-switches.
-
-@item SWITCH_TYPE_LINE_START
-This option can be ignored by this target hook.
-
-@item SWITCH_TYPE_LINE_END
-This option can be ignored by this target hook.
-@end table
-
-The hook's return value must be zero. Other return values may be
-supported in the future.
-
-By default this hook is set to NULL, but an example implementation is
-provided for ELF based targets. Called @var{elf_record_gcc_switches},
-it records the switches as ASCII text inside a new, string mergeable
-section in the assembler output file. The name of the new section is
-provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target
-hook.
-@end deftypefn
@hook TARGET_ASM_RECORD_GCC_SWITCHES_SECTION
-This is the name of the section that will be created by the example
-ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target
-hook.
-@end deftypevr
@need 2000
@node Data Output
@hook TARGET_ASM_BYTE_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP
-@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP
-These hooks specify assembly directives for creating certain kinds
-of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a
-byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an
-aligned two-byte object, and so on. Any of the hooks may be
-@code{NULL}, indicating that no suitable directive is available.
-
-The compiler will print these strings at the start of a new line,
-followed immediately by the object's initial value. In most cases,
-the string should contain a tab, a pseudo-op, and then another tab.
-@end deftypevr
@hook TARGET_ASM_INTEGER
-The @code{assemble_integer} function uses this hook to output an
-integer object. @var{x} is the object's value, @var{size} is its size
-in bytes and @var{aligned_p} indicates whether it is aligned. The
-function should return @code{true} if it was able to output the
-object. If it returns false, @code{assemble_integer} will try to
-split the object into smaller parts.
-
-The default implementation of this hook will use the
-@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}
-when the relevant string is @code{NULL}.
-@end deftypefn
+
+@hook TARGET_ASM_DECL_END
@hook TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA
-A target hook to recognize @var{rtx} patterns that @code{output_addr_const}
-can't deal with, and output assembly code to @var{file} corresponding to
-the pattern @var{x}. This may be used to allow machine-dependent
-@code{UNSPEC}s to appear within constants.
-
-If target hook fails to recognize a pattern, it must return @code{false},
-so that a standard error message is printed. If it prints an error message
-itself, by calling, for example, @code{output_operand_lossage}, it may just
-return @code{true}.
-@end deftypefn
@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
A C statement to output to the stdio stream @var{stream} an assembler
@end defmac
@hook TARGET_ASM_OPEN_PAREN
-These target hooks are C string constants, describing the syntax in the
-assembler for grouping arithmetic expressions. If not overridden, they
-default to normal parentheses, which is correct for most assemblers.
-@end deftypevr
These macros are provided by @file{real.h} for writing the definitions
of @code{ASM_OUTPUT_DOUBLE} and the like:
of this macro.
@end defmac
+@defmac ASM_DECLARE_COLD_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the name @var{name} of a
+cold function partition which is being defined. This macro is responsible
+for outputting the label definition (perhaps using
+@code{ASM_OUTPUT_FUNCTION_LABEL}). The argument @var{decl} is the
+@code{FUNCTION_DECL} tree node representing the function.
+
+If this macro is not defined, then the cold partition name is defined in the
+usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
+
+You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
+of this macro.
+@end defmac
+
+@defmac ASM_DECLARE_COLD_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the size of a cold function
+partition which is being defined. The argument @var{name} is the name of the
+cold partition of the function. The argument @var{decl} is the
+@code{FUNCTION_DECL} tree node representing the function.
+
+If this macro is not defined, then the partition size is not defined.
+
+You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
+of this macro.
+@end defmac
+
@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of an
@end defmac
@hook TARGET_ASM_DECLARE_CONSTANT_NAME
-A target hook to output to the stdio stream @var{file} any text necessary
-for declaring the name @var{name} of a constant which is being defined. This
-target hook is responsible for outputting the label definition (perhaps using
-@code{assemble_label}). The argument @var{exp} is the value of the constant,
-and @var{size} is the size of the constant in bytes. The @var{name}
-will be an internal label.
-
-The default version of this target hook, define the @var{name} in the
-usual manner as a label (by means of @code{assemble_label}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.
-@end deftypefn
@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@end defmac
@hook TARGET_ASM_GLOBALIZE_LABEL
-This target hook is a function to output to the stdio stream
-@var{stream} some commands that will make the label @var{name} global;
-that is, available for reference from other files.
-
-The default implementation relies on a proper definition of
-@code{GLOBAL_ASM_OP}.
-@end deftypefn
@hook TARGET_ASM_GLOBALIZE_DECL_NAME
-This target hook is a function to output to the stdio stream
-@var{stream} some commands that will make the name associated with @var{decl}
-global; that is, available for reference from other files.
-The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.
-@end deftypefn
+@hook TARGET_ASM_ASSEMBLE_UNDEFINED_DECL
@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@end defmac
@hook TARGET_ASM_ASSEMBLE_VISIBILITY
-This target hook is a function to output to @var{asm_out_file} some
-commands that will make the symbol(s) associated with @var{decl} have
-hidden, protected or internal visibility as specified by @var{visibility}.
-@end deftypefn
@defmac TARGET_WEAK_NOT_IN_ARCHIVE_TOC
A C expression that evaluates to true if the target's linker expects
@end defmac
@hook TARGET_ASM_EXTERNAL_LIBCALL
-This target hook is a function to output to @var{asm_out_file} an assembler
-pseudo-op to declare a library function name external. The name of the
-library function is given by @var{symref}, which is a @code{symbol_ref}.
-@end deftypefn
@hook TARGET_ASM_MARK_DECL_PRESERVED
-This target hook is a function to output to @var{asm_out_file} an assembler
-directive to annotate @var{symbol} as used. The Darwin target uses the
-.no_dead_code_strip directive.
-@end deftypefn
@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@end defmac
@hook TARGET_ASM_INTERNAL_LABEL
-A function to output to the stdio stream @var{stream} a label whose
-name is made from the string @var{prefix} and the number @var{labelno}.
-
-It is absolutely essential that these labels be distinct from the labels
-used for user-level functions and variables. Otherwise, certain programs
-will have name conflicts with internal labels.
-
-It is desirable to exclude internal labels from the symbol table of the
-object file. Most assemblers have a naming convention for labels that
-should be excluded; on many systems, the letter @samp{L} at the
-beginning of a label has this effect. You should find out what
-convention your system uses, and follow it.
-
-The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.
-@end deftypefn
@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
A C statement to output to the stdio stream @var{stream} a debug info
@end defmac
@hook TARGET_HAVE_CTORS_DTORS
-This value is true if the target supports some ``native'' method of
-collecting constructors and destructors to be run at startup and exit.
-It is false if we must use @command{collect2}.
-@end deftypevr
@hook TARGET_ASM_CONSTRUCTOR
-If defined, a function that outputs assembler code to arrange to call
-the function referenced by @var{symbol} at initialization time.
-
-Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking
-no arguments and with no return value. If the target supports initialization
-priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};
-otherwise it must be @code{DEFAULT_INIT_PRIORITY}.
-
-If this macro is not defined by the target, a suitable default will
-be chosen if (1) the target supports arbitrary section names, (2) the
-target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}
-is not defined.
-@end deftypefn
@hook TARGET_ASM_DESTRUCTOR
-This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination
-functions rather than initialization functions.
-@end deftypefn
If @code{TARGET_HAVE_CTORS_DTORS} is true, the initialization routine
generated for the generated object file will have static linkage.
@end defmac
@hook TARGET_ASM_FINAL_POSTSCAN_INSN
-If defined, this target hook is a function which is executed just after the
-output of assembler code for @var{insn}, to change the mode of the assembler
-if necessary.
-
-Here the argument @var{opvec} is the vector containing the operands
-extracted from @var{insn}, and @var{noperands} is the number of
-elements of the vector which contain meaningful data for this insn.
-The contents of this vector are what was used to convert the insn
-template into assembler code, so you can change the assembler mode
-by checking the contents of the vector.
-@end deftypefn
@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
A C compound statement to output to stdio stream @var{stream} the
@code{ASSEMBLER_DIALECT} is zero, one, two, etc. Any special characters
within these strings retain their usual meaning. If there are fewer
alternatives within the braces than the value of
-@code{ASSEMBLER_DIALECT}, the construct outputs nothing.
+@code{ASSEMBLER_DIALECT}, the construct outputs nothing. If it's needed
+to print curly braces or @samp{|} character in assembler output directly,
+@samp{%@{}, @samp{%@}} and @samp{%|} can be used.
If you do not define this macro, the characters @samp{@{}, @samp{|} and
@samp{@}} do not have any special meaning when used in templates or
Define this if the label before a jump-table needs to be output
specially. The first three arguments are the same as for
@code{(*targetm.asm_out.internal_label)}; the fourth argument is the
-jump-table which follows (a @code{jump_insn} containing an
+jump-table which follows (a @code{jump_table_data} containing an
@code{addr_vec} or @code{addr_diff_vec}).
This feature is used on system V to output a @code{swbeg} statement
@end defmac
@hook TARGET_ASM_EMIT_UNWIND_LABEL
-This target hook emits a label at the beginning of each FDE@. It
-should be defined on targets where FDEs need special labels, and it
-should write the appropriate label, for the FDE associated with the
-function declaration @var{decl}, to the stdio stream @var{stream}.
-The third argument, @var{for_eh}, is a boolean: true if this is for an
-exception table. The fourth argument, @var{empty}, is a boolean:
-true if this is a placeholder label for an omitted FDE@.
-
-The default is that FDEs are not given nonlocal labels.
-@end deftypefn
@hook TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL
-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
@hook TARGET_ASM_EMIT_EXCEPT_PERSONALITY
@hook TARGET_ASM_UNWIND_EMIT
-This target hook emits assembly directives required to unwind the
-given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}
-returns @code{UI_TARGET}.
-@end deftypefn
@hook TARGET_ASM_UNWIND_EMIT_BEFORE_INSN
This macro need only be defined if the target might save registers in the
function prologue at an offset to the stack pointer that is not aligned to
@code{UNITS_PER_WORD}. The definition should be the negative minimum
-alignment if @code{STACK_GROWS_DOWNWARD} is defined, and the positive
+alignment if @code{STACK_GROWS_DOWNWARD} is true, and the positive
minimum alignment otherwise. @xref{SDB and DWARF}. Only applicable if
the target supports DWARF 2 frame unwind information.
@end defmac
@hook 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.
-Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and
-true otherwise.
-@end deftypevr
@hook TARGET_DWARF_REGISTER_SPAN
-Given a register, this hook should return a parallel of registers to
-represent where to find the register pieces. Define this hook if the
-register and its mode are represented in Dwarf in non-contiguous
-locations, or if the register should be represented in more than one
-register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.
-If not defined, the default is to return @code{NULL_RTX}.
-@end deftypefn
+
+@hook TARGET_DWARF_FRAME_REG_MODE
@hook TARGET_INIT_DWARF_REG_SIZES_EXTRA
-If some registers are represented in Dwarf-2 unwind information in
-multiple pieces, define this hook to fill in information about the
-sizes of those pieces in the table used by the unwinder at runtime.
-It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after
-filling in a single size corresponding to each hard register;
-@var{address} is the address of the table.
-@end deftypefn
@hook TARGET_ASM_TTYPE
-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
@hook TARGET_ARM_EABI_UNWINDER
-This flag 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 deftypevr
@node Alignment Output
@subsection Assembler Commands for Alignment
@end defmac
@hook TARGET_ASM_JUMP_ALIGN_MAX_SKIP
-The maximum number of bytes to skip before @var{label} when applying
-@code{JUMP_ALIGN}. This works only if
-@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
-@end deftypefn
@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label})
The alignment (log base 2) to put in front of @var{label}, which follows
@end defmac
@hook TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
-The maximum number of bytes to skip before @var{label} when applying
-@code{LABEL_ALIGN_AFTER_BARRIER}. This works only if
-@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
-@end deftypefn
@defmac LOOP_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label}, which follows
-a @code{NOTE_INSN_LOOP_BEG} note.
+The alignment (log base 2) to put in front of @var{label} that heads
+a frequently executed basic block (usually the header of a loop).
This macro need not be defined if you don't want any special alignment
to be done at such a time. Most machine descriptions do not currently
@end defmac
@hook TARGET_ASM_LOOP_ALIGN_MAX_SKIP
-The maximum number of bytes to skip when applying @code{LOOP_ALIGN} to
-@var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is
-defined.
-@end deftypefn
@defmac LABEL_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}.
@end defmac
@hook TARGET_ASM_LABEL_ALIGN_MAX_SKIP
-The maximum number of bytes to skip when applying @code{LABEL_ALIGN}
-to @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}
-is defined.
-@end deftypefn
@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
A C statement to output to the stdio stream @var{stream} an assembler
debugging output in response to the @option{-g} option.
@hook TARGET_DWARF_CALLING_CONVENTION
-Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to
-be emitted for each function. Instead of an integer return the enum
-value for the @code{DW_CC_} tag.
-@end deftypefn
To support optional call frame debugging information, you must also
define @code{INCOMING_RETURN_ADDR_RTX} and either set
@end defmac
@hook TARGET_DEBUG_UNWIND_INFO
-This hook defines the mechanism that will be used for describing frame
-unwind information to the debugger. Normally the hook will return
-@code{UI_DWARF2} if DWARF 2 debug information is enabled, and
-return @code{UI_NONE} otherwise.
-
-A target may return @code{UI_DWARF2} even when DWARF 2 debug information
-is disabled in order to always output DWARF 2 frame information.
-
-A target may return @code{UI_TARGET} if it has ABI specified unwind tables.
-This will suppress generation of the normal debug frame unwind information.
-@end deftypefn
@defmac DWARF2_ASM_LINE_DEBUG_INFO
Define this macro to be a nonzero value if the assembler can generate Dwarf 2
@hook TARGET_DELAY_VARTRACK
+@hook TARGET_NO_REGISTER_ALLOCATION
+
@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
A C statement to issue assembly directives that create a difference
@var{lab1} minus @var{lab2}, using an integer of the given @var{size}.
@end defmac
@hook TARGET_ASM_OUTPUT_DWARF_DTPREL
-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
@var{x} is negative, returns zero.
@end deftypefn
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, enum machine_mode @var{mode})
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, machine_mode @var{mode})
Converts @var{string} into a floating point number in the target machine's
representation for mode @var{mode}. This routine can handle both
decimal and hexadecimal floating point constants, using the syntax
Returns the absolute value of @var{x}.
@end deftypefn
-@deftypefn Macro void REAL_VALUE_TO_INT (HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, REAL_VALUE_TYPE @var{x})
-Converts a floating point value @var{x} into a double-precision integer
-which is then stored into @var{low} and @var{high}. If the value is not
-integral, it is truncated.
-@end deftypefn
-
-@deftypefn Macro void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE @var{x}, HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, enum machine_mode @var{mode})
-Converts a double-precision integer found in @var{low} and @var{high},
-into a floating point value which is then stored into @var{x}. The
-value is truncated to fit in mode @var{mode}.
-@end deftypefn
-
@node Mode Switching
@section Mode Switching Instructions
@cindex mode switching
which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should
return nonzero for any @var{entity} that needs mode-switching.
If you define this macro, you also have to define
-@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
-@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
-@code{MODE_AFTER}, @code{MODE_ENTRY}, and @code{MODE_EXIT}
+@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{TARGET_MODE_NEEDED},
+@code{TARGET_MODE_PRIORITY} and @code{TARGET_MODE_EMIT}.
+@code{TARGET_MODE_AFTER}, @code{TARGET_MODE_ENTRY}, and @code{TARGET_MODE_EXIT}
are optional.
@end defmac
switch is needed / supplied.
@end defmac
-@defmac MODE_NEEDED (@var{entity}, @var{insn})
-@var{entity} is an integer specifying a mode-switched entity. If
-@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to
-return an integer value not larger than the corresponding element in
-@code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must
-be switched into prior to the execution of @var{insn}.
-@end defmac
+@hook TARGET_MODE_EMIT
-@defmac MODE_AFTER (@var{entity}, @var{mode}, @var{insn})
-@var{entity} is an integer specifying a mode-switched entity. If
-this macro is defined, it is evaluated for every @var{insn} during
-mode switching. It determines the mode that an insn results in (if
-different from the incoming mode).
-@end defmac
+@hook TARGET_MODE_NEEDED
-@defmac MODE_ENTRY (@var{entity})
-If this macro is defined, it is evaluated for every @var{entity} that needs
-mode switching. It should evaluate to an integer, which is a mode that
-@var{entity} is assumed to be switched to at function entry. If @code{MODE_ENTRY}
-is defined then @code{MODE_EXIT} must be defined.
-@end defmac
+@hook TARGET_MODE_AFTER
-@defmac MODE_EXIT (@var{entity})
-If this macro is defined, it is evaluated for every @var{entity} that needs
-mode switching. It should evaluate to an integer, which is a mode that
-@var{entity} is assumed to be switched to at function exit. If @code{MODE_EXIT}
-is defined then @code{MODE_ENTRY} must be defined.
-@end defmac
+@hook TARGET_MODE_ENTRY
-@defmac MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
-This macro specifies the order in which modes for @var{entity} are processed.
-0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the
-lowest. The value of the macro should be an integer designating a mode
-for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode}
-(@var{entity}, @var{n}) shall be a bijection in 0 @dots{}
-@code{num_modes_for_mode_switching[@var{entity}] - 1}.
-@end defmac
+@hook TARGET_MODE_EXIT
-@defmac EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
-Generate one or more insns to set @var{entity} to @var{mode}.
-@var{hard_reg_live} is the set of hard registers live at the point where
-the insn(s) are to be inserted.
-@end defmac
+@hook TARGET_MODE_PRIORITY
@node Target Attributes
@section Defining target-specific uses of @code{__attribute__}
be documented in @file{extend.texi}.
@hook TARGET_ATTRIBUTE_TABLE
-If defined, this target hook points to an array of @samp{struct
-attribute_spec} (defined in @file{tree.h}) specifying the machine
-specific attributes for this target and some of the restrictions on the
-entities to which these attributes are applied and the arguments they
-take.
-@end deftypevr
@hook TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P
-If defined, this target hook is a function which returns true if the
-machine-specific attribute named @var{name} expects an identifier
-given as its first argument to be passed on as a plain identifier, not
-subjected to name lookup. If this is not defined, the default is
-false for all machine-specific attributes.
-@end deftypefn
@hook TARGET_COMP_TYPE_ATTRIBUTES
-If defined, this target hook is a function which returns zero if the attributes on
-@var{type1} and @var{type2} are incompatible, one if they are compatible,
-and two if they are nearly compatible (which causes a warning to be
-generated). If this is not defined, machine-specific attributes are
-supposed always to be compatible.
-@end deftypefn
@hook TARGET_SET_DEFAULT_TYPE_ATTRIBUTES
-If defined, this target hook is a function which assigns default attributes to
-the newly defined @var{type}.
-@end deftypefn
@hook TARGET_MERGE_TYPE_ATTRIBUTES
-Define this target hook if the merging of type attributes needs special
-handling. If defined, the result is a list of the combined
-@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed
-that @code{comptypes} has already been called and returned 1. This
-function may call @code{merge_attributes} to handle machine-independent
-merging.
-@end deftypefn
@hook TARGET_MERGE_DECL_ATTRIBUTES
-Define this target hook if the merging of decl attributes needs special
-handling. If defined, the result is a list of the combined
-@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.
-@var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of
-when this is needed are when one attribute overrides another, or when an
-attribute is nullified by a subsequent definition. This function may
-call @code{merge_attributes} to handle machine-independent merging.
-
-@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES
-If the only target-specific handling you require is @samp{dllimport}
-for Microsoft Windows targets, you should define the macro
-@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler
-will then define a function called
-@code{merge_dllimport_decl_attributes} which can then be defined as
-the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also
-add @code{handle_dll_attribute} in the attribute table for your port
-to perform initial processing of the @samp{dllimport} and
-@samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and
-@file{i386/i386.c}, for example.
-@end deftypefn
@hook TARGET_VALID_DLLIMPORT_ATTRIBUTE_P
@end defmac
@hook TARGET_INSERT_ATTRIBUTES
-Define this target hook if you want to be able to add attributes to a decl
-when it is being created. This is normally useful for back ends which
-wish to implement a pragma by using the attributes which correspond to
-the pragma's effect. The @var{node} argument is the decl which is being
-created. The @var{attr_ptr} argument is a pointer to the attribute list
-for this decl. The list itself should not be modified, since it may be
-shared with other decls, but attributes may be chained on the head of
-the list and @code{*@var{attr_ptr}} modified to point to the new
-attributes, or a copy of the list may be made if further changes are
-needed.
-@end deftypefn
@hook TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P
-@cindex inlining
-This target hook returns @code{true} if it is ok to inline @var{fndecl}
-into the current function, despite its having target-specific
-attributes, @code{false} otherwise. By default, if a function has a
-target specific attribute attached to it, it will not be inlined.
-@end deftypefn
@hook TARGET_OPTION_VALID_ATTRIBUTE_P
-This hook is called to parse the @code{attribute(option("..."))}, and
-it allows the function to set different target machine compile time
-options for the current function that might be different than the
-options specified on the command line. The hook should return
-@code{true} if the options are valid.
-
-The hook should set the @var{DECL_FUNCTION_SPECIFIC_TARGET} field in
-the function declaration to hold a pointer to a target specific
-@var{struct cl_target_option} structure.
-@end deftypefn
@hook TARGET_OPTION_SAVE
-This hook is called to save any additional target specific information
-in the @var{struct cl_target_option} structure for function specific
-options.
-@xref{Option file format}.
-@end deftypefn
@hook TARGET_OPTION_RESTORE
-This hook is called to restore any additional target specific
-information in the @var{struct cl_target_option} structure for
-function specific options.
-@end deftypefn
+
+@hook TARGET_OPTION_POST_STREAM_IN
@hook TARGET_OPTION_PRINT
-This hook is called to print any additional target specific
-information in the @var{struct cl_target_option} structure for
-function specific options.
-@end deftypefn
@hook TARGET_OPTION_PRAGMA_PARSE
-This target hook parses the options for @code{#pragma GCC option} to
-set the machine specific options for functions that occur later in the
-input stream. The options should be the same as handled by the
-@code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.
-@end deftypefn
@hook TARGET_OPTION_OVERRIDE
-Sometimes certain combinations of command options do not make sense on
-a particular target machine. You can override the hook
-@code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called
-once just after all the command options have been parsed.
-
-Don't use this hook to turn on various extra optimizations for
-@option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.
-
-If you need to do something whenever the optimization level is
-changed via the optimize attribute or pragma, see
-@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}
-@end deftypefn
@hook TARGET_OPTION_FUNCTION_VERSIONS
-This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are
-versions of the same function. @var{DECL1} and @var{DECL2} are function
-versions if and only if they have the same function signature and
-different target specific attributes, that is, they are compiled for
-different target machines.
-@end deftypefn
@hook TARGET_CAN_INLINE_P
-This target hook returns @code{false} if the @var{caller} function
-cannot inline @var{callee}, based on target specific information. By
-default, inlining is not allowed if the callee function has function
-specific target options and the caller does not use the same options.
-@end deftypefn
@node Emulated TLS
@section Emulating TLS
address of the current thread's instance of the TLS object.
@hook TARGET_EMUTLS_GET_ADDRESS
-Contains the name of the helper function that uses a TLS control
-object to locate a TLS instance. The default causes libgcc's
-emulated TLS helper function to be used.
-@end deftypevr
@hook TARGET_EMUTLS_REGISTER_COMMON
-Contains the name of the helper function that should be used at
-program startup to register TLS objects that are implicitly
-initialized to zero. If this is @code{NULL}, all TLS objects will
-have explicit initializers. The default causes libgcc's emulated TLS
-registration function to be used.
-@end deftypevr
@hook TARGET_EMUTLS_VAR_SECTION
-Contains the name of the section in which TLS control variables should
-be placed. The default of @code{NULL} allows these to be placed in
-any section.
-@end deftypevr
@hook TARGET_EMUTLS_TMPL_SECTION
-Contains the name of the section in which TLS initializers should be
-placed. The default of @code{NULL} allows these to be placed in any
-section.
-@end deftypevr
@hook TARGET_EMUTLS_VAR_PREFIX
-Contains the prefix to be prepended to TLS control variable names.
-The default of @code{NULL} uses a target-specific prefix.
-@end deftypevr
@hook TARGET_EMUTLS_TMPL_PREFIX
-Contains the prefix to be prepended to TLS initializer objects. The
-default of @code{NULL} uses a target-specific prefix.
-@end deftypevr
@hook TARGET_EMUTLS_VAR_FIELDS
-Specifies a function that generates the FIELD_DECLs for a TLS control
-object type. @var{type} is the RECORD_TYPE the fields are for and
-@var{name} should be filled with the structure tag, if the default of
-@code{__emutls_object} is unsuitable. The default creates a type suitable
-for libgcc's emulated TLS function.
-@end deftypefn
@hook TARGET_EMUTLS_VAR_INIT
-Specifies a function that generates the CONSTRUCTOR to initialize a
-TLS control object. @var{var} is the TLS control object, @var{decl}
-is the TLS object and @var{tmpl_addr} is the address of the
-initializer. The default initializes libgcc's emulated TLS control object.
-@end deftypefn
@hook TARGET_EMUTLS_VAR_ALIGN_FIXED
-Specifies whether the alignment of TLS control variable objects is
-fixed and should not be increased as some backends may do to optimize
-single objects. The default is false.
-@end deftypevr
@hook TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS
-Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor
-may be used to describe emulated TLS control objects.
-@end deftypevr
@node MIPS Coprocessors
@section Defining coprocessor specifics for MIPS targets.
the FPU@. One accesses COP1 registers through standard mips
floating-point support; they are not included in this mechanism.
-There is one macro used in defining the MIPS coprocessor interface which
-you may want to override in subtargets; it is described below.
-
@node PCH Target
@section Parameters for Precompiled Header Validity Checking
@cindex parameters, precompiled headers
@hook TARGET_GET_PCH_VALIDITY
-This hook returns a pointer to the data needed by
-@code{TARGET_PCH_VALID_P} and sets
-@samp{*@var{sz}} to the size of the data in bytes.
-@end deftypefn
@hook TARGET_PCH_VALID_P
-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
@hook TARGET_CHECK_PCH_TARGET_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
@hook TARGET_PREPARE_PCH_SAVE
@cindex parameters, c++ abi
@hook TARGET_CXX_GUARD_TYPE
-Define this hook to override the integer type used for guard variables.
-These are used to implement one-time construction of static objects. The
-default is long_long_integer_type_node.
-@end deftypefn
@hook TARGET_CXX_GUARD_MASK_BIT
-This hook determines how guard variables are used. It should return
-@code{false} (the default) if the first byte should be used. A return value of
-@code{true} indicates that only the least significant bit should be used.
-@end deftypefn
@hook TARGET_CXX_GET_COOKIE_SIZE
-This hook returns the size of the cookie to use when allocating an array
-whose elements have the indicated @var{type}. Assumes that it is already
-known that a cookie is needed. The default is
-@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the
-IA64/Generic C++ ABI@.
-@end deftypefn
@hook TARGET_CXX_COOKIE_HAS_SIZE
-This hook should return @code{true} if the element size should be stored in
-array cookies. The default is to return @code{false}.
-@end deftypefn
@hook TARGET_CXX_IMPORT_EXPORT_CLASS
-If defined by a backend this hook allows the decision made to export
-class @var{type} to be overruled. Upon entry @var{import_export}
-will contain 1 if the class is going to be exported, @minus{}1 if it is going
-to be imported and 0 otherwise. This function should return the
-modified value and perform any other actions necessary to support the
-backend's targeted operating system.
-@end deftypefn
@hook TARGET_CXX_CDTOR_RETURNS_THIS
-This hook should return @code{true} if constructors and destructors return
-the address of the object created/destroyed. The default is to return
-@code{false}.
-@end deftypefn
@hook TARGET_CXX_KEY_METHOD_MAY_BE_INLINE
-This hook returns true if the key method for a class (i.e., the method
-which, if defined in the current translation unit, causes the virtual
-table to be emitted) may be an inline function. Under the standard
-Itanium C++ ABI the key method may be an inline function so long as
-the function is not declared inline in the class definition. Under
-some variants of the ABI, an inline function can never be the key
-method. The default is to return @code{true}.
-@end deftypefn
@hook TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY
@hook TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT
-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
@hook TARGET_CXX_LIBRARY_RTTI_COMDAT
-This hook returns true (the default) if the RTTI information for
-the basic types which is defined in the C++ runtime should always
-be COMDAT, false if it should not be COMDAT.
-@end deftypefn
@hook TARGET_CXX_USE_AEABI_ATEXIT
-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
@hook TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT
-This hook returns true if the target @code{atexit} function can be used
-in the same manner as @code{__cxa_atexit} to register C++ static
-destructors. This requires that @code{atexit}-registered functions in
-shared libraries are run in the correct order when the libraries are
-unloaded. The default is to return false.
-@end deftypefn
@hook TARGET_CXX_ADJUST_CLASS_AT_DEFINITION
@end smallexample
@hook TARGET_ADDR_SPACE_POINTER_MODE
-Define this to return the machine mode to use for pointers to
-@var{address_space} if the target supports named address spaces.
-The default version of this hook returns @code{ptr_mode} for the
-generic address space only.
-@end deftypefn
@hook TARGET_ADDR_SPACE_ADDRESS_MODE
-Define this to return the machine mode to use for addresses in
-@var{address_space} if the target supports named address spaces.
-The default version of this hook returns @code{Pmode} for the
-generic address space only.
-@end deftypefn
@hook TARGET_ADDR_SPACE_VALID_POINTER_MODE
-Define this to return nonzero if the port can handle pointers
-with machine mode @var{mode} to address space @var{as}. This target
-hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,
-except that it includes explicit named address space support. The default
-version of this hook returns true for the modes returned by either the
-@code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}
-target hooks for the given address space.
-@end deftypefn
@hook TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P
-Define this to return true if @var{exp} is a valid address for mode
-@var{mode} in the named address space @var{as}. The @var{strict}
-parameter says whether strict addressing is in effect after reload has
-finished. This target hook is the same as the
-@code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes
-explicit named address space support.
-@end deftypefn
@hook TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS
-Define this to modify an invalid address @var{x} to be a valid address
-with mode @var{mode} in the named address space @var{as}. This target
-hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,
-except that it includes explicit named address space support.
-@end deftypefn
@hook TARGET_ADDR_SPACE_SUBSET_P
-Define this to return whether the @var{subset} named address space is
-contained within the @var{superset} named address space. Pointers to
-a named address space that is a subset of another named address space
-will be converted automatically without a cast if used together in
-arithmetic operations. Pointers to a superset address space can be
-converted to pointers to a subset address space via explicit casts.
-@end deftypefn
@hook TARGET_ADDR_SPACE_CONVERT
-Define this to convert the pointer expression represented by the RTL
-@var{op} with type @var{from_type} that points to a named address
-space to a new pointer expression with type @var{to_type} that points
-to a different named address space. When this hook it called, it is
-guaranteed that one of the two address spaces is a subset of the other,
-as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.
-@end deftypefn
@node Misc
@section Miscellaneous Parameters
@end defmac
@hook TARGET_CASE_VALUES_THRESHOLD
-This function return the smallest number of different values for which it
-is best to use a jump-table instead of a tree of conditional branches.
-The default is four for machines with a @code{casesi} instruction and
-five otherwise. This is best for most machines.
-@end deftypefn
@defmac WORD_REGISTER_OPERATIONS
-Define this macro if operations between registers with integral mode
+Define this macro to 1 if operations between registers with integral mode
smaller than a word are always performed on the entire register.
Most RISC machines have this property and most CISC machines do not.
@end defmac
@end defmac
@defmac SHORT_IMMEDIATES_SIGN_EXTEND
-Define this macro if loading short immediate values into registers sign
+Define this macro to 1 if loading short immediate values into registers sign
extends.
@end defmac
@hook TARGET_MIN_DIVISIONS_FOR_RECIP_MUL
-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
@anchor{TARGET_SHIFT_TRUNCATION_MASK}
@hook TARGET_SHIFT_TRUNCATION_MASK
-This function describes how the standard shift patterns for @var{mode}
-deal with shifts by negative amounts or by more than the width of the mode.
-@xref{shift patterns}.
-
-On many machines, the shift patterns will apply a mask @var{m} to the
-shift count, meaning that a fixed-width shift of @var{x} by @var{y} is
-equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If
-this is true for mode @var{mode}, the function should return @var{m},
-otherwise it should return 0. A return value of 0 indicates that no
-particular behavior is guaranteed.
-
-Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does
-@emph{not} apply to general shift rtxes; it applies only to instructions
-that are generated by the named shift patterns.
-
-The default implementation of this function returns
-@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}
-and 0 otherwise. This definition is always safe, but if
-@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns
-nevertheless truncate the shift count, you may get better code
-by overriding it.
-@end deftypefn
@defmac TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
A C expression which is nonzero if on this machine it is safe to
@end defmac
@hook TARGET_MODE_REP_EXTENDED
-The representation of an integral mode can be such that the values
-are always extended to a wider integral mode. Return
-@code{SIGN_EXTEND} if values of @var{mode} are represented in
-sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}
-otherwise. (Currently, none of the targets use zero-extended
-representation this way so unlike @code{LOAD_EXTEND_OP},
-@code{TARGET_MODE_REP_EXTENDED} is expected to return either
-@code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends
-@var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next
-widest integral mode and currently we take advantage of this fact.)
-
-Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}
-value even if the extension is not performed on certain hard registers
-as long as for the @code{REGNO_REG_CLASS} of these hard registers
-@code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.
-
-Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}
-describe two related properties. If you define
-@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want
-to define @code{LOAD_EXTEND_OP (mode)} to return the same type of
-extension.
-
-In order to enforce the representation of @code{mode},
-@code{TRULY_NOOP_TRUNCATION} should return false when truncating to
-@code{mode}.
-@end deftypefn
@defmac STORE_FLAG_VALUE
A C expression describing the value returned by a comparison operator
@hook TARGET_C_PREINCLUDE
+@hook TARGET_CXX_IMPLICIT_EXTERN_C
+
@defmac NO_IMPLICIT_EXTERN_C
Define this macro if the system header files support C++ as well as C@.
This macro inhibits the usual method of using system header files in
You need not define this macro if it would always evaluate to zero.
@end defmac
-@hook TARGET_MD_ASM_CLOBBERS
-This target hook should add to @var{clobbers} @code{STRING_CST} trees for
-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. 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{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test
-for overlap with regards to asm-declared registers.
-@end deftypefn
+@hook TARGET_MD_ASM_ADJUST
@defmac MATH_LIBRARY
Define this macro as a C string constant for the linker argument to link
@end defmac
@hook TARGET_MACHINE_DEPENDENT_REORG
-If non-null, this hook performs a target-specific pass over the
-instruction stream. The compiler will run it at all optimization levels,
-just before the point at which it normally does delayed-branch scheduling.
-
-The exact purpose of the hook varies from target to target. Some use
-it to do transformations that are necessary for correctness, such as
-laying out in-function constant pools or avoiding hardware hazards.
-Others use it as an opportunity to do some machine-dependent optimizations.
-
-You need not implement the hook if it has nothing to do. The default
-definition is null.
-@end deftypefn
@hook TARGET_INIT_BUILTINS
-Define this hook if you have any machine-specific built-in functions
-that need to be defined. It should be a function that performs the
-necessary setup.
-
-Machine specific built-in functions can be useful to expand special machine
-instructions that would otherwise not normally be generated because
-they have no equivalent in the source language (for example, SIMD vector
-instructions or prefetch instructions).
-
-To create a built-in function, call the function
-@code{lang_hooks.builtin_function}
-which is defined by the language front end. You can use any type nodes set
-up by @code{build_common_tree_nodes};
-only language front ends that use those two functions will call
-@samp{TARGET_INIT_BUILTINS}.
-@end deftypefn
@hook TARGET_BUILTIN_DECL
-Define this hook if you have any machine-specific built-in functions
-that need to be defined. It should be a function that returns the
-builtin function declaration for the builtin function code @var{code}.
-If there is no such builtin and it cannot be initialized at this time
-if @var{initialize_p} is true the function should return @code{NULL_TREE}.
-If @var{code} is out of range the function should return
-@code{error_mark_node}.
-@end deftypefn
@hook TARGET_EXPAND_BUILTIN
-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 should go to @var{target} if that is
-convenient, and have mode @var{mode} if that is convenient.
-@var{subtarget} may be used as the target for computing one of
-@var{exp}'s operands. @var{ignore} is nonzero if the value is to be
-ignored. This function should return the result of the call to the
-built-in function.
-@end deftypefn
+@hook TARGET_BUILTIN_CHKP_FUNCTION
+@hook TARGET_CHKP_BOUND_TYPE
+@hook TARGET_CHKP_BOUND_MODE
+@hook TARGET_CHKP_MAKE_BOUNDS_CONSTANT
+@hook TARGET_CHKP_INITIALIZE_BOUNDS
@hook TARGET_RESOLVE_OVERLOADED_BUILTIN
-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}.
-@var{arglist} really has type @samp{VEC(tree,gc)*}
-@end deftypefn
@hook TARGET_FOLD_BUILTIN
-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{n_args} is the number of arguments passed to
-the function; the arguments themselves are pointed to by @var{argp}.
-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
+
+@hook TARGET_GIMPLE_FOLD_BUILTIN
@hook TARGET_COMPARE_VERSION_PRIORITY
-This hook is used to compare the target attributes in two functions to
-determine which function's features get higher priority. This is used
-during function multi-versioning to figure out the order in which two
-versions must be dispatched. A function version with a higher priority
-is checked for dispatching earlier. @var{decl1} and @var{decl2} are
- the two function decls that will be compared.
-@end deftypefn
@hook TARGET_GET_FUNCTION_VERSIONS_DISPATCHER
-This hook is used to get the dispatcher function for a set of function
-versions. The dispatcher function is called to invoke the right function
-version at run-time. @var{decl} is one version from a set of semantically
-identical versions.
-@end deftypefn
@hook TARGET_GENERATE_VERSION_DISPATCHER_BODY
-This hook is used to generate the dispatcher logic to invoke the right
-function version at run-time for a given set of function versions.
-@var{arg} points to the callgraph node of the dispatcher function whose
-body must be generated.
-@end deftypefn
-@hook TARGET_INVALID_WITHIN_DOLOOP
-
-Take an instruction in @var{insn} and return NULL if it is valid within a
-low-overhead loop, otherwise return a string explaining why doloop
-could not be applied.
+@hook TARGET_CAN_USE_DOLOOP_P
-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
+@hook TARGET_INVALID_WITHIN_DOLOOP
@hook TARGET_LEGITIMATE_COMBINED_INSN
-@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
-
-Take a branch insn in @var{branch1} and another in @var{branch2}.
-Return true if redirecting @var{branch1} to the destination of
-@var{branch2} is possible.
-
-On some targets, branches may have a limited range. Optimizing the
-filling of delay slots can result in branches being redirected, and this
-may in turn cause a branch offset to overflow.
-@end defmac
-
@hook TARGET_CAN_FOLLOW_JUMP
@hook TARGET_COMMUTATIVE_P
-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
@hook TARGET_ALLOCATE_INITIAL_VALUE
-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{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
-the hard register itself, if it is known not to be clobbered---or a
-@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_is_leaf} or
-@code{REG_N_SETS} in the hook to determine if the hard
-register in question will not be clobbered.
-The default value of this hook is @code{NULL}, which disables any special
-allocation.
-@end deftypefn
-
@hook TARGET_UNSPEC_MAY_TRAP_P
-This target hook returns nonzero if @var{x}, an @code{unspec} or
-@code{unspec_volatile} operation, might cause a trap. Targets can use
-this hook to enhance precision of analysis for @code{unspec} and
-@code{unspec_volatile} operations. You may call @code{may_trap_p_1}
-to analyze inner elements of @var{x} in which case @var{flags} should be
-passed along.
-@end deftypefn
@hook TARGET_SET_CURRENT_FUNCTION
-The compiler invokes this hook whenever it changes its current function
-context (@code{cfun}). You can define this function if
-the back end needs to perform any initialization or reset actions on a
-per-function basis. For example, it may be used to implement function
-attributes that affect register usage or code generation patterns.
-The argument @var{decl} is the declaration for the new function context,
-and may be null to indicate that the compiler has left a function context
-and is returning to processing at the top level.
-The default hook function does nothing.
-
-GCC sets @code{cfun} to a dummy function context during initialization of
-some parts of the back end. The hook function is not invoked in this
-situation; you need not worry about the hook being invoked recursively,
-or when the back end is in a partially-initialized state.
-@code{cfun} might be @code{NULL} to indicate processing at top level,
-outside of any function scope.
-@end deftypefn
@defmac TARGET_OBJECT_SUFFIX
Define this macro to be a C string representing the suffix for object
@end defmac
@hook TARGET_CANNOT_MODIFY_JUMPS_P
-This target hook returns @code{true} past the point in which new jump
-instructions could be created. On machines that require a register for
-every jump such as the SHmedia ISA of SH5, this point would typically be
-reload, so this target hook should be defined to a function such as:
-
-@smallexample
-static bool
-cannot_modify_jumps_past_reload_p ()
-@{
- return (reload_completed || reload_in_progress);
-@}
-@end smallexample
-@end deftypefn
@hook TARGET_BRANCH_TARGET_REGISTER_CLASS
-This target hook returns a register class for which branch target register
-optimizations should be applied. All registers in this class should be
-usable interchangeably. After reload, registers in this class will be
-re-allocated and loads will be hoisted out of loops and be subjected
-to inter-block scheduling.
-@end deftypefn
@hook TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED
-Branch target register optimization will by default exclude callee-saved
-registers
-that are not already live during the current function; if this target hook
-returns true, they will be included. The target code must than make sure
-that all target registers in the class returned by
-@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are
-saved. @var{after_prologue_epilogue_gen} indicates if prologues and
-epilogues have already been generated. Note, even if you only return
-true when @var{after_prologue_epilogue_gen} is false, you still are likely
-to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}
-to reserve space for caller-saved target registers.
-@end deftypefn
@hook TARGET_HAVE_CONDITIONAL_EXECUTION
-This target hook returns true if the target supports conditional execution.
-This target hook is required only when the target has several different
-modes and they have different conditional execution capability, such as ARM.
-@end deftypefn
+
+@hook TARGET_GEN_CCMP_FIRST
+
+@hook TARGET_GEN_CCMP_NEXT
@hook TARGET_LOOP_UNROLL_ADJUST
-This target hook returns a new value for the number of times @var{loop}
-should be unrolled. The parameter @var{nunroll} is the number of times
-the loop is to be unrolled. The parameter @var{loop} is a pointer to
-the loop, which is going to be checked for unrolling. This target hook
-is required only when the target has special constraints like maximum
-number of memory accesses.
-@end deftypefn
@defmac POWI_MAX_MULTS
If defined, this macro is interpreted as a signed integer C expression
and scanf formatter settings.
@end defmac
-@hook 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 deftypevr
-
@hook TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN
-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
@hook TARGET_INVALID_CONVERSION
-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
@hook TARGET_INVALID_UNARY_OP
-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
@hook TARGET_INVALID_BINARY_OP
-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
@hook TARGET_INVALID_PARAMETER_TYPE
-If defined, this macro returns the diagnostic message when it is
-invalid for functions to include parameters of type @var{type},
-or @code{NULL} if validity should be determined by
-the front end. This is currently used only by the C and C++ front ends.
-@end deftypefn
@hook TARGET_INVALID_RETURN_TYPE
-If defined, this macro returns the diagnostic message when it is
-invalid for functions to have return type @var{type},
-or @code{NULL} if validity should be determined by
-the front end. This is currently used only by the C and C++ front ends.
-@end deftypefn
@hook TARGET_PROMOTED_TYPE
-If defined, this target hook returns the type to which values of
-@var{type} should be promoted when they appear in expressions,
-analogous to the integer promotions, or @code{NULL_TREE} to use the
-front end's normal promotion rules. This hook is useful when there are
-target-specific types with special promotion rules.
-This is currently used only by the C and C++ front ends.
-@end deftypefn
@hook TARGET_CONVERT_TO_TYPE
-If defined, this hook returns the result of converting @var{expr} to
-@var{type}. It should return the converted expression,
-or @code{NULL_TREE} to apply the front end's normal conversion rules.
-This hook is useful when there are target-specific types with special
-conversion rules.
-This is currently used only by the C and C++ front ends.
-@end deftypefn
@defmac TARGET_USE_JCR_SECTION
This macro determines whether to use the JCR section to register Java
@end defmac
@hook TARGET_UPDATE_STACK_BOUNDARY
-Define this macro to update the current function stack boundary if
-necessary.
-@end deftypefn
@hook TARGET_GET_DRAP_RTX
-This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a
-different argument pointer register is needed to access the function's
-argument list due to stack realignment. Return @code{NULL} if no DRAP
-is needed.
-@end deftypefn
@hook TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS
-When optimization is disabled, this hook indicates whether or not
-arguments should be allocated to stack slots. Normally, GCC allocates
-stacks slots for arguments when not optimizing in order to make
-debugging easier. However, when a function is declared with
-@code{__attribute__((naked))}, there is no stack frame, and the compiler
-cannot safely move arguments from the registers in which they are passed
-to the stack. Therefore, this hook should return true in general, but
-false for naked functions. The default implementation always returns true.
-@end deftypefn
@hook TARGET_CONST_ANCHOR
-On some architectures it can take multiple instructions to synthesize
-a constant. If there is another constant already in a register that
-is close enough in value then it is preferable that the new constant
-is computed from this register using immediate addition or
-subtraction. We accomplish this through CSE. Besides the value of
-the constant we also add a lower and an upper constant anchor to the
-available expressions. These are then queried when encountering new
-constants. The anchors are computed by rounding the constant up and
-down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.
-@code{TARGET_CONST_ANCHOR} should be the maximum positive value
-accepted by immediate-add plus one. We currently assume that the
-value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on
-MIPS, where add-immediate takes a 16-bit signed value,
-@code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value
-is zero, which disables this optimization.
-@end deftypevr
+
+@hook TARGET_ASAN_SHADOW_OFFSET
@hook TARGET_MEMMODEL_CHECK
-Validate target specific memory model mask bits. When NULL no target specific
-memory model bits are allowed.
-@end deftypefn
@hook TARGET_ATOMIC_TEST_AND_SET_TRUEVAL
+
+@hook TARGET_HAS_IFUNC_P
+
+@hook TARGET_ATOMIC_ALIGN_FOR_MODE
+
+@hook TARGET_ATOMIC_ASSIGN_EXPAND_FENV
+
+@hook TARGET_RECORD_OFFLOAD_SYMBOL
+
+@hook TARGET_OFFLOAD_OPTIONS
+
+@defmac TARGET_SUPPORTS_WIDE_INT
+
+On older ports, large integers are stored in @code{CONST_DOUBLE} rtl
+objects. Newer ports define @code{TARGET_SUPPORTS_WIDE_INT} to be nonzero
+to indicate that large integers are stored in
+@code{CONST_WIDE_INT} rtl objects. The @code{CONST_WIDE_INT} allows
+very large integer constants to be represented. @code{CONST_DOUBLE}
+is limited to twice the size of the host's @code{HOST_WIDE_INT}
+representation.
+
+Converting a port mostly requires looking for the places where
+@code{CONST_DOUBLE}s are used with @code{VOIDmode} and replacing that
+code with code that accesses @code{CONST_WIDE_INT}s. @samp{"grep -i
+const_double"} at the port level gets you to 95% of the changes that
+need to be made. There are a few places that require a deeper look.
+
+@itemize @bullet
+@item
+There is no equivalent to @code{hval} and @code{lval} for
+@code{CONST_WIDE_INT}s. This would be difficult to express in the md
+language since there are a variable number of elements.
+
+Most ports only check that @code{hval} is either 0 or -1 to see if the
+value is small. As mentioned above, this will no longer be necessary
+since small constants are always @code{CONST_INT}. Of course there
+are still a few exceptions, the alpha's constraint used by the zap
+instruction certainly requires careful examination by C code.
+However, all the current code does is pass the hval and lval to C
+code, so evolving the c code to look at the @code{CONST_WIDE_INT} is
+not really a large change.
+
+@item
+Because there is no standard template that ports use to materialize
+constants, there is likely to be some futzing that is unique to each
+port in this code.
+
+@item
+The rtx costs may have to be adjusted to properly account for larger
+constants that are represented as @code{CONST_WIDE_INT}.
+@end itemize
+
+All and all it does not take long to convert ports that the
+maintainer is familiar with.
+
+@end defmac
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