@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
-@c 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+@c 2002, 2003, 2004, 2005, 2006, 2007, 2008 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.
* Library Calls:: Controlling how library routines are implicitly called.
* Addressing Modes:: Defining addressing modes valid for memory operands.
+* Anchored Addresses:: Defining how @option{-fsection-anchors} should work.
* Condition Code:: Defining how insns update the condition code.
* Costs:: Defining relative costs of different operations.
* Scheduling:: Adjusting the behavior of the instruction scheduler.
Any prefixes specified by the user with @option{-B}.
@item
-The environment variable @code{GCC_EXEC_PREFIX}, if any.
+The environment variable @code{GCC_EXEC_PREFIX} or, if @code{GCC_EXEC_PREFIX}
+is not set and the compiler has not been installed in the configure-time
+@var{prefix}, the location in which the compiler has actually been installed.
@item
The directories specified by the environment variable @code{COMPILER_PATH}.
@item
-The macro @code{STANDARD_EXEC_PREFIX}.
+The macro @code{STANDARD_EXEC_PREFIX}, if the compiler has been installed
+in the configured-time @var{prefix}.
@item
-@file{/usr/lib/gcc/}.
+The location @file{/usr/libexec/gcc/}, but only if this is a native compiler.
@item
-The macro @code{MD_EXEC_PREFIX}, if any.
+The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
+
+@item
+The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
+compiler.
@end enumerate
Here is the order of prefixes tried for startfiles:
Any prefixes specified by the user with @option{-B}.
@item
-The environment variable @code{GCC_EXEC_PREFIX}, if any.
+The environment variable @code{GCC_EXEC_PREFIX} or its automatically determined
+value based on the installed toolchain location.
@item
The directories specified by the environment variable @code{LIBRARY_PATH}
(or port-specific name; native only, cross compilers do not use this).
@item
-The macro @code{STANDARD_EXEC_PREFIX}.
+The macro @code{STANDARD_EXEC_PREFIX}, but only if the toolchain is installed
+in the configured @var{prefix} or this is a native compiler.
+
+@item
+The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
@item
-@file{/usr/lib/gcc/}.
+The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
+compiler.
@item
-The macro @code{MD_EXEC_PREFIX}, if any.
+The macro @code{MD_STARTFILE_PREFIX}, if defined, but only if this is a
+native compiler, or we have a target system root.
@item
-The macro @code{MD_STARTFILE_PREFIX}, if any.
+The macro @code{MD_STARTFILE_PREFIX_1}, if defined, but only if this is a
+native compiler, or we have a target system root.
@item
-The macro @code{STANDARD_STARTFILE_PREFIX}.
+The macro @code{STANDARD_STARTFILE_PREFIX}, with any sysroot modifications.
+If this path is relative it will be prefixed by @code{GCC_EXEC_PREFIX} and
+the machine suffix or @code{STANDARD_EXEC_PREFIX} and the machine suffix.
@item
+The macro @code{STANDARD_STARTFILE_PREFIX_1}, but only if this is a native
+compiler, or we have a target system root. The default for this macro is
@file{/lib/}.
@item
+The macro @code{STANDARD_STARTFILE_PREFIX_2}, but only if this is a native
+compiler, or we have a target system root. The default for this macro is
@file{/usr/lib/}.
@end enumerate
@defmac TARGET_CPU_CPP_BUILTINS ()
This function-like macro expands to a block of code that defines
-built-in preprocessor macros and assertions for the target cpu, using
+built-in preprocessor macros and assertions for the target CPU, using
the functions @code{builtin_define}, @code{builtin_define_std} and
@code{builtin_assert}. When the front end
calls this macro it provides a trailing semicolon, and since it has
option was used and 0 if the ``no-'' form was.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_HANDLE_C_OPTION (size_t @var{code}, const char *@var{arg}, int @var{value})
+This target hook is called whenever the user specifies one of the
+target-specific C language family options described by the @file{.opt}
+definition files(@pxref{Options}). It has the opportunity to do some
+option-specific processing and should return true if the option is
+valid. The default definition does nothing but return false.
+
+In general, you should use @code{TARGET_HANDLE_OPTION} to handle
+options. However, if processing an option requires routines that are
+only available in the C (and related language) front ends, then you
+should use @code{TARGET_HANDLE_C_OPTION} instead.
+@end deftypefn
+
@defmac TARGET_VERSION
This macro is a C statement to print on @code{stderr} a string
describing the particular machine description choice. Every machine
@option{-O}. That is what @code{OPTIMIZATION_OPTIONS} is for.
@end defmac
+@defmac C_COMMON_OVERRIDE_OPTIONS
+This is similar to @code{OVERRIDE_OPTIONS} but is only used in the C
+language frontends (C, Objective-C, C++, Objective-C++) and so can be
+used to alter option flag variables which only exist in those
+frontends.
+@end defmac
+
@defmac OPTIMIZATION_OPTIONS (@var{level}, @var{size})
Some machines may desire to change what optimizations are performed for
various optimization levels. This macro, if defined, is executed once
generated code.
@end defmac
+@deftypefn {Target Hook} bool TARGET_HELP (void)
+This hook is called in response to the user invoking
+@option{--target-help} on the command line. It gives the target a
+chance to display extra information on the target specific command
+line options found in its @file{.opt} file.
+@end deftypefn
+
@defmac CAN_DEBUG_WITHOUT_FP
Define this macro if debugging can be performed even without a frame
pointer. If this macro is defined, GCC will turn on the
@end defmac
@defmac POINTERS_EXTEND_UNSIGNED
-A C expression whose value is greater than zero if pointers that need to be
-extended from being @code{POINTER_SIZE} bits wide to @code{Pmode} are to
-be zero-extended and zero if they are to be sign-extended. If the value
-is less then zero then there must be an "ptr_extend" instruction that
-extends a pointer from @code{POINTER_SIZE} to @code{Pmode}.
+A C expression that determines how pointers should be extended from
+@code{ptr_mode} to either @code{Pmode} or @code{word_mode}. It is
+greater than zero if pointers should be zero-extended, zero if they
+should be sign-extended, and negative if some other sort of conversion
+is needed. In the last case, the extension is done by the target's
+@code{ptr_extend} instruction.
-You need not define this macro if the @code{POINTER_SIZE} is equal
-to the width of @code{Pmode}.
+You need not define this macro if the @code{ptr_mode}, @code{Pmode}
+and @code{word_mode} are all the same width.
@end defmac
@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
@code{PROMOTE_FUNCTION_MODE} should be done for the return value of
functions.
-If this target hook returns @code{true}, @code{FUNCTION_VALUE} must
-perform the same promotions done by @code{PROMOTE_FUNCTION_MODE}.
+If this target hook returns @code{true}, @code{TARGET_FUNCTION_VALUE}
+must perform the same promotions done by @code{PROMOTE_FUNCTION_MODE}.
@end deftypefn
@defmac PARM_BOUNDARY
@end defmac
@defmac BIGGEST_ALIGNMENT
-Biggest alignment that any data type can require on this machine, in bits.
+Biggest alignment that any data type can require on this machine, in
+bits. Note that this is not the biggest alignment that is supported,
+just the biggest alignment that, when violated, may cause a fault.
@end defmac
@defmac MINIMUM_ATOMIC_ALIGNMENT
Use this macro to limit the alignment which can be specified using the
@code{__attribute__ ((aligned (@var{n})))} construct. If not defined,
the default value is @code{BIGGEST_ALIGNMENT}.
+
+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)}.
+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
@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align})
the alignment requirements of an unnamed bitfield's type.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_NARROW_VOLATILE_BITFIELDS (void)
+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
+
@defmac MEMBER_TYPE_FORCES_BLK (@var{field}, @var{mode})
Return 1 if a structure or array containing @var{field} should be accessed using
@code{BLKMODE}.
case where structures of one field would require the structure's mode to
retain the field's mode.
-Normally, this is not needed. See the file @file{c4x.h} for an example
-of how to use this macro to prevent a structure having a floating point
-field from being accessed in an integer mode.
+Normally, this is not needed.
@end defmac
@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
pattern needs to support both a 32- and a 64-bit mode.
@end defmac
+@deftypefn {Target Hook} {enum machine_mode} 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
+
+@deftypefn {Target Hook} {enum machine_mode} 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
+
@defmac TARGET_FLOAT_FORMAT
A code distinguishing the floating point format of the target machine.
-There are four defined values:
+There are two defined values:
@ftable @code
@item IEEE_FLOAT_FORMAT
@item VAX_FLOAT_FORMAT
This code indicates the ``F float'' (for @code{float}) and ``D float''
or ``G float'' formats (for @code{double}) used on the VAX and PDP-11@.
-
-@item IBM_FLOAT_FORMAT
-This code indicates the format used on the IBM System/370.
-
-@item C4X_FLOAT_FORMAT
-This code indicates the format used on the TMS320C3x/C4x.
@end ftable
If your target uses a floating point format other than these, you must
Returns true if the target supports decimal floating point.
@end deftypefn
-@deftypefn {Target Hook} {const char *} TARGET_MANGLE_FUNDAMENTAL_TYPE (tree @var{type})
-If your target defines any fundamental types, define this hook to
-return the appropriate encoding for these types as part of a C++
-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.
+@deftypefn {Target Hook} {bool} TARGET_FIXED_POINT_SUPPORTED_P (void)
+Returns true if the target supports fixed-point arithmetic.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_MANGLE_TYPE (tree @var{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
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.
words.
@end defmac
+@defmac SHORT_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{short _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT}.
+@end defmac
+
+@defmac FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{_Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 2}.
+@end defmac
+
+@defmac LONG_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{long _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 4}.
+@end defmac
+
+@defmac LONG_LONG_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{long long _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 8}.
+@end defmac
+
+@defmac SHORT_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{short _Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 2}.
+@end defmac
+
+@defmac ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{_Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 4}.
+@end defmac
+
+@defmac LONG_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{long _Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 8}.
+@end defmac
+
+@defmac LONG_LONG_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{long long _Accum} on
+the target machine. If you don't define this, the default is
+@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
@end defmac
@defmac LIBGCC2_HAS_DF_MODE
-Define this macro if neither @code{LIBGCC2_DOUBLE_TYPE_SIZE} nor
+Define this macro if neither @code{LIBGCC2_DOUBLE_TYPE_SIZE} nor
@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is
@code{DFmode} but you want @code{DFmode} routines in @file{libgcc2.a}
anyway. If you don't define this and either @code{LIBGCC2_DOUBLE_TYPE_SIZE}
@end defmac
@defmac LIBGCC2_HAS_XF_MODE
-Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not
+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
+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.
@defmac HARD_REGNO_NREGS (@var{regno}, @var{mode})
A C expression for the number of consecutive hard registers, starting
at register number @var{regno}, required to hold a value of mode
-@var{mode}.
+@var{mode}. This macro must never return zero, even if a register
+cannot hold the requested mode - indicate that with HARD_REGNO_MODE_OK
+and/or CANNOT_CHANGE_MODE_CLASS instead.
On a machine where all registers are exactly one word, a suitable
definition of this macro is
@end smallexample
@end defmac
+@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode})
+A C expression that is nonzero if a value of mode @var{mode}, stored
+in memory, ends with padding that causes it to take up more space than
+in registers starting at register number @var{regno} (as determined by
+multiplying GCC's notion of the size of the register when containing
+this mode by the number of registers returned by
+@code{HARD_REGNO_NREGS}). By default this is zero.
+
+For example, if a floating-point value is stored in three 32-bit
+registers but takes up 128 bits in memory, then this would be
+nonzero.
+
+This macros only needs to be defined if there are cases where
+@code{subreg_get_info}
+would otherwise wrongly determine that a @code{subreg} can be
+represented by an offset to the register number, when in fact such a
+@code{subreg} would contain some of the padding not stored in
+registers and so not be representable.
+@end defmac
+
+@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode})
+For values of @var{regno} and @var{mode} for which
+@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression
+returning the greater number of registers required to hold the value
+including any padding. In the example above, the value would be four.
+@end defmac
+
@defmac REGMODE_NATURAL_SIZE (@var{mode})
Define this macro if the natural size of registers that hold values
of mode @var{mode} is not the word size. It is a C expression that
addresses have different requirements than other base register uses.
@end defmac
+@defmac MODE_CODE_BASE_REG_CLASS (@var{mode}, @var{outer_code}, @var{index_code})
+A C expression whose value is the register class to which a valid
+base register must belong. @var{outer_code} and @var{index_code} define the
+context in which the base register occurs. @var{outer_code} is the code of
+the immediately enclosing expression (@code{MEM} for the top level of an
+address, @code{ADDRESS} for something that occurs in an
+@code{address_operand}). @var{index_code} is the code of the corresponding
+index expression if @var{outer_code} is @code{PLUS}; @code{SCRATCH} otherwise.
+@end defmac
+
@defmac INDEX_REG_CLASS
A macro whose definition is the name of the class to which a valid
index register must belong. An index register is one used in an
added to another register (as well as added to a displacement).
@end defmac
-@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 REGNO_OK_FOR_BASE_P (@var{num})
A C expression which is nonzero if register number @var{num} is
suitable for use as a base register in operand addresses. It may be
@var{mode}. You should define this macro if the mode of the memory
reference affects whether a register may be used as a base register. If
you define this macro, the compiler will use it instead of
-@code{REGNO_OK_FOR_BASE_P}.
+@code{REGNO_OK_FOR_BASE_P}. The mode may be @code{VOIDmode} for
+addresses that appear outside a @code{MEM}, i.e., as an
+@code{address_operand}.
+
@end defmac
@defmac REGNO_MODE_OK_FOR_REG_BASE_P (@var{num}, @var{mode})
pseudo register that has been allocated such a hard register. You should
define this macro if base plus index addresses have different requirements
than other base register uses.
+
+Use of this macro is deprecated; please use the more general
+@code{REGNO_MODE_CODE_OK_FOR_BASE_P}.
+@end defmac
+
+@defmac REGNO_MODE_CODE_OK_FOR_BASE_P (@var{num}, @var{mode}, @var{outer_code}, @var{index_code})
+A C expression that is just like @code{REGNO_MODE_OK_FOR_BASE_P}, except
+that that expression may examine the context in which the register
+appears in the memory reference. @var{outer_code} is the code of the
+immediately enclosing expression (@code{MEM} if at the top level of the
+address, @code{ADDRESS} for something that occurs in an
+@code{address_operand}). @var{index_code} is the code of the
+corresponding index expression if @var{outer_code} is @code{PLUS};
+@code{SCRATCH} otherwise. The mode may be @code{VOIDmode} for addresses
+that appear outside a @code{MEM}, i.e., as an @code{address_operand}.
@end defmac
@defmac REGNO_OK_FOR_INDEX_P (@var{num})
into any kind of register, code generation will be better if
@code{LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead
of using @code{PREFERRED_RELOAD_CLASS}.
+
+If an insn has pseudos in it after register allocation, reload will go
+through the alternatives and call repeatedly @code{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 defmac
@defmac PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
Like @code{PREFERRED_RELOAD_CLASS}, but for output reloads instead of
input reloads. If you don't define this macro, the default is to use
@var{class}, unchanged.
+
+You can also use @code{PREFERRED_OUTPUT_RELOAD_CLASS} to discourage
+reload from using some alternatives, like @code{PREFERRED_RELOAD_CLASS}.
@end defmac
@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
require the macro to do something nontrivial.
@end defmac
-@deftypefn {Target Hook} enum reg_class TARGET_SECONDARY_RELOAD (bool @var{in_p}, rtx @var{x}, enum reg_class @var{reload_class}, enum machine_mode @var{reload_mode}, secondary_reload_info *@var{sri})
+@deftypefn {Target Hook} {enum reg_class} TARGET_SECONDARY_RELOAD (bool @var{in_p}, rtx @var{x}, enum reg_class @var{reload_class}, enum machine_mode @var{reload_mode}, secondary_reload_info *@var{sri})
Many machines have some registers that cannot be copied directly to or
from memory or even from other types of registers. An example is the
@samp{MQ} register, which on most machines, can only be copied to or
In some cases, both an intermediate and a scratch register are required.
For input reloads, this target hook is called with nonzero @var{in_p},
-and @var{x} is an rtx that needs to be copied to a register in of class
+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_mode}
+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
@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-These macros are obsolete, new ports should use the target hook
+These macros are obsolete, new ports should use the target hook
@code{TARGET_SECONDARY_RELOAD} instead.
These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD}
@end smallexample
@end defmac
-Three other special macros describe which operands fit which constraint
-letters.
+@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
@defmac INITIAL_FRAME_ADDRESS_RTX
A C expression whose value is RTL representing the address of the initial
-stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
+stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
@code{DYNAMIC_CHAIN_ADDRESS}. If you don't define this macro, a reasonable
default value will be used. Define this macro in order to make frame pointer
-elimination work in the presence of @code{__builtin_frame_address (count)} and
+elimination work in the presence of @code{__builtin_frame_address (count)} and
@code{__builtin_return_address (count)} for @code{count} not equal to zero.
@end defmac
@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 current frame. @var{frameaddr} is the frame pointer
+of the current frame. This is used for __builtin_frame_address.
+You need only define this macro if the frame address is not the same
+as the frame pointer. Most machines do not need to define it.
+@end defmac
+
@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
A C expression whose value is RTL representing the value of the return
address for the frame @var{count} steps up from the current frame, after
@defmac DWARF_ALT_FRAME_RETURN_COLUMN
A C expression whose value is an integer giving a DWARF 2 column
-number that may be used as an alternate return column. This should
-be defined only if @code{DWARF_FRAME_RETURN_COLUMN} is set to a
-general register, but an alternate column needs to be used for
-signal frames.
+number that may be used as an alternative return column. The column
+must not correspond to any gcc hard register (that is, it must not
+be in the range of @code{DWARF_FRAME_REGNUM}).
+
+This macro can be useful if @code{DWARF_FRAME_RETURN_COLUMN} is set to a
+general register, but an alternative column needs to be used for signal
+frames. Some targets have also used different frame return columns
+over time.
@end defmac
@defmac DWARF_ZERO_REG
@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl})
If defined, a C expression whose value is an integer giving the offset
in bytes from the frame pointer to the canonical frame address (cfa).
-The final value should conincide with that calculated by
+The final value should coincide with that calculated by
@code{INCOMING_FRAME_SP_OFFSET}.
Normally the CFA is calculated as an offset from the argument pointer,
-via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
+via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
variable due to the ABI, this may not be possible. If this macro is
defined, it implies that the virtual register instantiation should be
based on the frame pointer instead of the argument pointer. Only one
should be defined.
@end defmac
+@defmac CFA_FRAME_BASE_OFFSET (@var{fundecl})
+If defined, a C expression whose value is an integer giving the offset
+in bytes from the canonical frame address (cfa) to the frame base used
+in DWARF 2 debug information. The default is zero. A different value
+may reduce the size of debug information on some ports.
+@end defmac
+
@node Exception Handling
@subsection Exception Handling Support
@cindex exception handling
@end defmac
@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs})
-This macro allows the target to add cpu and operating system specific
+This macro allows the target to add CPU and operating system specific
code to the call-frame unwinder for use when there is no unwind data
available. The most common reason to implement this macro is to unwind
through signal frames.
-This macro is called from @code{uw_frame_state_for} in @file{unwind-dw2.c}
-and @file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
+This macro is called from @code{uw_frame_state_for} in
+@file{unwind-dw2.c}, @file{unwind-dw2-xtensa.c} and
+@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
@var{fs} is an @code{_Unwind_FrameState}. Examine @code{context->ra}
for the address of the code being executed and @code{context->cfa} for
-the stack pointer value. If the frame can be decoded, the register save
-addresses should be updated in @var{fs} and the macro should evaluate to
-@code{_URC_NO_REASON}. If the frame cannot be decoded, the macro should
-evaluate to @code{_URC_END_OF_STACK}.
+the stack pointer value. If the frame can be decoded, the register
+save addresses should be updated in @var{fs} and the macro should
+evaluate to @code{_URC_NO_REASON}. If the frame cannot be decoded,
+the macro should evaluate to @code{_URC_END_OF_STACK}.
For proper signal handling in Java this macro is accompanied by
@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers.
@c something, not sure if it looks good. --mew 10feb93
@defmac OUTGOING_REG_PARM_STACK_SPACE
-Define this if it is the responsibility of the caller to allocate the area
-reserved for arguments passed in registers.
+Define this to a nonzero value if it is the responsibility of the caller
+to allocate the area reserved for arguments passed in registers.
If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
whether the space for these arguments counts in the value of
This section discusses the macros that control returning scalars as
values---values that can fit in registers.
-@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
-A C expression to create an RTX representing the place where a
-function returns a value of data type @var{valtype}. @var{valtype} is
-a tree node representing a data type. Write @code{TYPE_MODE
-(@var{valtype})} to get the machine mode used to represent that type.
-On many machines, only the mode 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{FUNCTION_ARG} for an explanation of the @code{parallel} form.
-
-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.
+@deftypefn {Target Hook} rtx TARGET_FUNCTION_VALUE (tree @var{ret_type}, tree @var{fn_decl_or_type}, bool @var{outgoing})
+
+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
+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{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
convention for specific functions when all their calls are
known.
-@code{FUNCTION_VALUE} is not used for return vales with aggregate data
-types, because these are returned in another way. See
+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
@defmac FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
-Define this macro if the target machine has ``register windows''
-so that the register in which a function returns its value is not
-the same as the one in which the caller sees the value.
-
-For such machines, @code{FUNCTION_VALUE} computes the register in which
-the caller will see the value. @code{FUNCTION_OUTGOING_VALUE} should be
-defined in a similar fashion to tell the function where to put the
-value.
-
-If @code{FUNCTION_OUTGOING_VALUE} is not defined,
-@code{FUNCTION_VALUE} serves both purposes.
-
-@code{FUNCTION_OUTGOING_VALUE} is not used for return vales with
-aggregate data types, because these are returned in another way. See
-@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.
+This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
+a new target instead.
@end defmac
@defmac LIBCALL_VALUE (@var{mode})
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{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{FUNCTION_VALUE} should provide an @code{SImode} rtx.
+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
@cindex structure value address
When a function value's mode is @code{BLKmode} (and in some other
-cases), the value is not returned according to @code{FUNCTION_VALUE}
-(@pxref{Scalar Return}). Instead, the caller passes the address of a
-block of memory in which the value should be stored. This address
-is called the @dfn{structure value address}.
+cases), the value is not returned according to
+@code{TARGET_FUNCTION_VALUE} (@pxref{Scalar Return}). Instead, the
+caller passes the address of a block of memory in which the value
+should be stored. This address is called the @dfn{structure value
+address}.
This section describes how to control returning structure values in
memory.
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{true} when the location is needed in
-the context of the called function, and @code{false} in the context of
+@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 @code{true} and the address is to be found on the
-stack, return a @code{mem} which refers to the frame pointer.
+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
@defmac EPILOGUE_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the epilogue or the @samp{return} pattern. The stack and frame
-pointer registers are already be assumed to be used as needed.
+pointer registers are already assumed to be used as needed.
@end defmac
@defmac EH_USES (@var{regno})
@end defmac
@defmac NO_PROFILE_COUNTERS
-Define this macro if the @code{mcount} subroutine on your system does
-not need a counter variable allocated for each function. This is true
-for almost all modern implementations. If you define this macro, you
-must not use the @var{labelno} argument to @code{FUNCTION_PROFILER}.
+Define this macro to be an expression with a nonzero value if the
+@code{mcount} subroutine on your system does not need a counter variable
+allocated for each function. This is true for almost all modern
+implementations. If you define this macro, you must not use the
+@var{labelno} argument to @code{FUNCTION_PROFILER}.
@end defmac
@defmac PROFILE_BEFORE_PROLOGUE
may vary greatly between different architectures.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap *@var{regs})
+Add any hard registers to @var{regs} that are live on entry to the
+function. This hook only needs to be defined to provide registers that
+cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved
+registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,
+TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,
+FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.
+@end deftypefn
+
@node Stack Smashing Protection
@subsection Stack smashing protection
@cindex stack smashing protection
@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_GUARD (void)
This hook returns a @code{DECL} node for the external variable to use
-for the stack protection guard. This variable is initialized by the
+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}.
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
+@samp{__stack_chk_fail}, taking no arguments. This function is
normally defined in @file{libgcc2.c}.
@end deftypefn
they needs this macro to be redefined to 0.
@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
+
@defmac NEXT_OBJC_RUNTIME
Define this macro to generate code for Objective-C message sending using
the calling convention of the NeXT system. This calling convention
Format}.
@end defmac
-@defmac REG_OK_FOR_BASE_P (@var{x})
-A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
-RTX) is valid for use as a base register. For hard registers, it
-should always accept those which the hardware permits and reject the
-others. Whether the macro accepts or rejects pseudo registers must be
-controlled by @code{REG_OK_STRICT} as described above. This usually
-requires two variant definitions, of which @code{REG_OK_STRICT}
-controls the one actually used.
-@end defmac
-
-@defmac REG_MODE_OK_FOR_BASE_P (@var{x}, @var{mode})
-A C expression that is just like @code{REG_OK_FOR_BASE_P}, except that
-that expression may examine the mode of the memory reference in
-@var{mode}. You should define this macro if the mode of the memory
-reference affects whether a register may be used as a base register. If
-you define this macro, the compiler will use it instead of
-@code{REG_OK_FOR_BASE_P}.
-@end defmac
-
-@defmac REG_MODE_OK_FOR_REG_BASE_P (@var{x}, @var{mode})
-A C expression which is nonzero if @var{x} (assumed to be a @code{reg} RTX)
-is suitable for use as a base register in base plus index operand addresses,
-accessing memory in mode @var{mode}. It may be either a suitable hard
-register or a pseudo register that has been allocated such a hard register.
-You should define this macro if base plus index addresses have different
-requirements than other base register uses.
-@end defmac
-
-@defmac REG_OK_FOR_INDEX_P (@var{x})
-A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
-RTX) is valid for use as an index register.
-
-The difference between an index register and a base register is that
-the index register may be scaled. If an address involves the sum of
-two registers, neither one of them scaled, then either one may be
-labeled the ``base'' and the other the ``index''; but whichever
-labeling is used must fit the machine's constraints of which registers
-may serve in each capacity. The compiler will try both labelings,
-looking for one that is valid, and will reload one or both registers
-only if neither labeling works.
-@end defmac
-
@defmac FIND_BASE_TERM (@var{x})
A C expression to determine the base term of address @var{x}.
This macro is used in only one place: `find_base_term' in alias.c.
@findex copy_rtx
If you want to change only a part of @var{x}, one standard way of doing
-this is to use @code{copy_rtx}. Note, however, that is unshares only a
+this is to use @code{copy_rtx}. Note, however, that it unshares only a
single level of rtl. Thus, if the part to be changed is not at the
top level, you'll need to replace first the top level.
It is not necessary for this macro to come up with a legitimate
of TLS symbols for various targets.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_USE_BLOCKS_FOR_CONSTANT_P (enum machine_mode @var{mode}, rtx @var{x})
+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
+
+@deftypefn {Target Hook} tree TARGET_BUILTIN_RECIPROCAL (enum tree_code @var{fn}, bool @var{tm_fn}, bool @var{sqrt})
+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{tm_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
+
@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void)
This hook should return the DECL of a function @var{f} that given an
address @var{addr} as an argument returns a mask @var{m} that can be
-used to extract from two vectors the relevant data that resides in
+used to extract from two vectors the relevant data that resides in
@var{addr} in case @var{addr} is not properly aligned.
-The autovectrizer, when vectorizing a load operation from an address
+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
@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{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}
+should comply with the semantics expected by @code{REALIGN_LOAD}
described above.
If this hook is not defined, then @var{addr} will be used as
the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low
log2(@var{VS})-1 bits of @var{addr} will be considered.
@end deftypefn
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN (tree @var{x})
+This hook should return the DECL of a function @var{f} that implements
+widening multiplication of the even elements of two input vectors of type @var{x}.
+
+If this hook is defined, the autovectorizer will use it along with the
+@code{TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD} target hook when vectorizing
+widening multiplication in cases that the order of the results does not have to be
+preserved (e.g. used only by a reduction computation). Otherwise, the
+@code{widen_mult_hi/lo} idioms will be used.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD (tree @var{x})
+This hook should return the DECL of a function @var{f} that implements
+widening multiplication of the odd elements of two input vectors of type @var{x}.
+
+If this hook is defined, the autovectorizer will use it along with the
+@code{TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN} target hook when vectorizing
+widening multiplication in cases that the order of the results does not have to be
+preserved (e.g. used only by a reduction computation). Otherwise, the
+@code{widen_mult_hi/lo} idioms will be used.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_CONVERSION (enum tree_code @var{code}, tree @var{type})
+This hook should return the DECL of a function that implements conversion of the
+input vector of type @var{type}.
+If @var{type} is an integral type, the result of the conversion is a vector of
+floating-point type of the same size.
+If @var{type} is a floating-point type, the result of the conversion is a vector
+of integral type of the same size.
+@var{code} 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
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION (enum built_in_function @var{code}, tree @var{vec_type_out}, tree @var{vec_type_in})
+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 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
+
+@node Anchored Addresses
+@section Anchored Addresses
+@cindex anchored addresses
+@cindex @option{-fsection-anchors}
+
+GCC usually addresses every static object as a separate entity.
+For example, if we have:
+
+@smallexample
+static int a, b, c;
+int foo (void) @{ return a + b + c; @}
+@end smallexample
+
+the code for @code{foo} will usually calculate three separate symbolic
+addresses: those of @code{a}, @code{b} and @code{c}. On some targets,
+it would be better to calculate just one symbolic address and access
+the three variables relative to it. The equivalent pseudocode would
+be something like:
+
+@smallexample
+int foo (void)
+@{
+ register int *xr = &x;
+ return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
+@}
+@end smallexample
+
+(which isn't valid C). We refer to shared addresses like @code{x} as
+``section anchors''. Their use is controlled by @option{-fsection-anchors}.
+
+The hooks below describe the target properties that GCC needs to know
+in order to make effective use of section anchors. It won't use
+section anchors at all unless either @code{TARGET_MIN_ANCHOR_OFFSET}
+or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value.
+
+@deftypevar {Target Hook} HOST_WIDE_INT 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 deftypevar
+
+@deftypevar {Target Hook} HOST_WIDE_INT 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 deftypevar
+
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_ANCHOR (rtx @var{x})
+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
+
+@deftypefn {Target Hook} bool TARGET_USE_ANCHORS_FOR_SYMBOL_P (rtx @var{x})
+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
@cindex condition code status
than @code{CLEAR_RATIO}.
@end defmac
+@defmac SET_RATIO
+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
+a block set insn or a library call.
+Increasing the value will always make code faster, but
+eventually incurs high cost in increased code size.
+
+If you don't define this, 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 value, or whether some other
-mechanism will be used. Used by @code{__builtin_memset} when storing
-values other than constant zero and by @code{__builtin_strcpy} when
-when called with a constant source string.
+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
This value must be constant over the entire compilation. If you need
it to vary depending on what the instructions are, you must use
@samp{TARGET_SCHED_VARIABLE_ISSUE}.
-
-You could define this hook to return the value of the macro
-@code{MAX_DFA_ISSUE_RATE}.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_PRIORITY (rtx @var{insn}, int @var{priority})
This hook adjusts the integer scheduling priority @var{priority} of
-@var{insn}. It should return the new priority. Reduce the priority to
-execute @var{insn} earlier, increase the priority to execute @var{insn}
+@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
used to initialize data used by the previous hook.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_SCHED_DFA_PRE_CYCLE_ADVANCE (void)
+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
+
+@deftypefn {Target Hook} void TARGET_SCHED_DFA_POST_CYCLE_ADVANCE (void)
+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
+
@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD (void)
This hook controls better choosing an insn from the ready insn queue
for the @acronym{DFA}-based insn scheduler. Usually the scheduler
issued and the current processor cycle.
@end deftypefn
-@deftypefn {Target Hook} bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (rtx @var{insn1}, rtx @var{insn2}, rtx @var{dep_link}, int @var{dep_cost}, int @var{distance})
+@deftypefn {Target Hook} bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (struct dep_def *@var{_dep}, int @var{cost}, int @var{distance})
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 second parameter @var{insn2} is dependent
-upon the first parameter @var{insn1}. The dependence between @var{insn1}
-and @var{insn2} is represented by the third parameter @var{dep_link}. The
-fourth parameter @var{cost} is the cost of the dependence, and the fifth
+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, 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,
not in cases of "costly dependences", which this hooks allows to define.
@end deftypefn
-Macros in the following table are generated by the program
-@file{genattr} and can be useful for writing the hooks.
+@deftypefn {Target Hook} void TARGET_SCHED_H_I_D_EXTENDED (void)
+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
-@defmac MAX_DFA_ISSUE_RATE
-The macro definition is generated in the automaton based pipeline
-description interface. Its value is calculated from the automaton
-based pipeline description and is equal to maximal number of all insns
-described in constructions @samp{define_insn_reservation} which can be
-issued on the same processor cycle.
-@end defmac
+@deftypefn {Target Hook} int TARGET_SCHED_SPECULATE_INSN (rtx @var{insn}, int @var{request}, rtx *@var{new_pat})
+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 -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
+
+@deftypefn {Target Hook} int TARGET_SCHED_NEEDS_BLOCK_P (rtx @var{insn})
+This hook is called by the insn scheduler during generation of recovery code
+for @var{insn}. It should return nonzero, if the corresponding check
+instruction should branch to recovery code, or zero otherwise.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_SCHED_GEN_CHECK (rtx @var{insn}, rtx @var{label}, int @var{mutate_p})
+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
+
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC (rtx @var{insn})
+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 instruction that stand first in the ready list from
+being scheduled on the current cycle. For non-speculative instructions,
+the hook should always return nonzero. For example, in the ia64 backend
+the hook is used to cancel data speculative insns when the ALAT table
+is nearly full.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_SET_SCHED_FLAGS (unsigned int *@var{flags}, spec_info_t @var{spec_info})
+This hook is used by the insn scheduler to find out what features should be
+enabled/used. @var{flags} initially may have either the SCHED_RGN or SCHED_EBB
+bit set. This denotes the scheduler pass for which the data should be
+provided. The target backend should modify @var{flags} by modifying
+the bits corresponding to the following features: USE_DEPS_LIST, USE_GLAT,
+DETACH_LIFE_INFO, and DO_SPECULATION. For the DO_SPECULATION feature
+an additional structure @var{spec_info} should be filled by the target.
+The structure describes speculation types that can be used in the scheduler.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_SMS_RES_MII (struct ddg *@var{g})
+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
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
defined, GCC will assume such a section does not exist. Do not define
both this macro and @code{INIT_SECTION_ASM_OP}.
@end defmac
-
+
@defmac FINI_ARRAY_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
constant pools don't end up too far way in the text section.
@end defmac
+@defmac TARGET_LIBGCC_SDATA_SECTION
+If defined, a string which names the section into which small
+variables defined in crtstuff and libgcc should go. This is useful
+when the target has options for optimizing access to small data, and
+you want the crtstuff and libgcc routines to be conservative in what
+they expect of your application yet liberal in what your application
+expects. For example, for targets with a @code{.sdata} section (like
+MIPS), you could compile crtstuff with @code{-G 0} so that it doesn't
+require small data support from your application, but use this macro
+to put small data into @code{.sdata} so that your application can
+access these variables whether it uses small data or not.
+@end defmac
+
@defmac FORCE_CODE_SECTION_ALIGN
If defined, an ASM statement that aligns a code section to some
arbitrary boundary. This is used to force all fragments of the
described below.
@end deftypefn
+@deftypefn {Target Hook} TARGET_ASM_RELOC_RW_MASK (void)
+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
+
@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align})
Return the section into which @var{exp} should be placed. You can
assume that @var{exp} is either a @code{VAR_DECL} node or a constant of
else in @code{readonly_data_section}.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_MANGLE_DECL_ASSEMBLER_NAME (tree @var{decl}, tree @var{id})
+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
+
@deftypefn {Target Hook} void TARGET_ENCODE_SECTION_INFO (tree @var{decl}, rtx @var{rtl}, int @var{new_decl_p})
Define this hook if references to a symbol or a constant must be
treated differently depending on something about the variable or
This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}.
@end deftypefn
+@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}
+@deftypefn {Target Hook} bool 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 deftypefn
+
@deftypefn {Target Hook} {unsigned int} TARGET_SECTION_TYPE_FLAGS (tree @var{decl}, const char *@var{name}, int @var{reloc})
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 if this function handles choosing code vs data,
+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
+@deftypefn {Target Hook} {int} TARGET_ASM_RECORD_GCC_SWITCHES (print_switch_type @var{type}, const char * @var{text})
+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
+
+@deftypefn {Target Hook} {const char *} 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 deftypefn
+
@need 2000
@node Data Output
@subsection Output of Data
define this macro.
@end defmac
-@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C})
+@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C}, @var{STR})
Define this macro as a C expression which is nonzero if @var{C} is
-used as a logical line separator by the assembler.
+used as a logical line separator by the assembler. @var{STR} points
+to the position in the string where @var{C} was found; this can be used if
+a line separator uses multiple characters.
If you do not define this macro, the default is that only
the character @samp{;} is treated as a logical line separator.
@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
-These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the target's
-floating point representation, and store its bit pattern in the variable
-@var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE}, this variable should
-be a simple @code{long int}. For the others, it should be an array of
-@code{long int}. The number of elements in this array is determined by
-the size of the desired target floating point data type: 32 bits of it
-go in each @code{long int} array element. Each array element holds 32
-bits of the result, even if @code{long int} is wider than 32 bits on the
-host machine.
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@var{x}, @var{l})
+These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the
+target's floating point representation, and store its bit pattern in
+the variable @var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE} and
+@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a
+simple @code{long int}. For the others, it should be an array of
+@code{long int}. The number of elements in this array is determined
+by the size of the desired target floating point data type: 32 bits of
+it go in each @code{long int} array element. Each array element holds
+32 bits of the result, even if @code{long int} is wider than 32 bits
+on the host machine.
The array element values are designed so that you can print them out
using @code{fprintf} in the order they should appear in the target
the variable's decl in order to chose what to output.
@end defmac
-@defmac ASM_OUTPUT_SHARED_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_COMMON}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_COMMON}
-will be used.
-@end defmac
-
@defmac ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of uninitialized global @var{decl} named
before and after that, output the additional assembler syntax for defining
the name, and a newline.
-This macro controls how the assembler definitions of uninitialized global
-variables are output. This macro exists to properly support languages like
-C++ which do not have @code{common} data. However, this macro currently
-is not defined for all targets. If this macro and
-@code{ASM_OUTPUT_ALIGNED_BSS} are not defined then @code{ASM_OUTPUT_COMMON}
-or @code{ASM_OUTPUT_ALIGNED_COMMON} or
-@code{ASM_OUTPUT_ALIGNED_DECL_COMMON} is used.
+There are two ways of handling global BSS. One is to define either
+this macro or its aligned counterpart, @code{ASM_OUTPUT_ALIGNED_BSS}.
+The other is to have @code{TARGET_ASM_SELECT_SECTION} return a
+switchable BSS section (@pxref{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}).
+You do not need to do both.
+
+Some languages do not have @code{common} data, and require a
+non-common form of global BSS in order to handle uninitialized globals
+efficiently. C++ is one example of this. However, if the target does
+not support global BSS, the front end may choose to make globals
+common in order to save space in the object file.
@end defmac
@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
@file{varasm.c} when defining this macro.
@end defmac
-@defmac ASM_OUTPUT_SHARED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_BSS}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_BSS}
-will be used.
-@end defmac
-
@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a local-common-label named
the variable's decl in order to chose what to output.
@end defmac
-@defmac ASM_OUTPUT_SHARED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_LOCAL}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_LOCAL}
-will be used.
-@end defmac
-
@node Label Output
@subsection Output and Generation of Labels
@code{GLOBAL_ASM_OP}.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_ASM_GLOBALIZE_DECL_NAME (FILE *@var{stream}, tree @var{decl})
+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
+
@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} some commands that will make the label @var{name} weak;
line. Otherwise, it must set @var{ptr} to @code{NULL}.
@end defmac
+@defmac SHLIB_SUFFIX
+Define this macro to a C string constant containing the default shared
+library extension of the target (e.g., @samp{".so"}). @command{collect2}
+strips version information after this suffix when generating global
+constructor and destructor names. This define is only needed on targets
+that use @command{collect2} to process constructors and destructors.
+@end defmac
+
@node Instruction Output
@subsection Output of Assembler Instructions
The default is that FDEs are not given nonlocal labels.
@end deftypefn
-@deftypefn {Taget Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn})
+@deftypefn {Target Hook} void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (@var{stream})
+This target hook emits a label at the beginning of the exception table.
+It should be defined on targets where it is desirable for the table
+to be broken up according to function.
+
+The default is that no label is emitted.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn})
This target hook emits and assembly directives required to unwind the
given instruction. This is only used when TARGET_UNWIND_INFO is set.
@end deftypefn
information, but it does not yet work with exception handling.
Otherwise, if your target supports this information (if it defines
@samp{INCOMING_RETURN_ADDR_RTX} and either @samp{UNALIGNED_INT_ASM_OP}
-or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of
-1.
+or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of 1.
If @code{TARGET_UNWIND_INFO} is defined, the target specific unwinder
will be used in all cases. Defining this macro will enable the generation
If @code{TARGET_UNWIND_INFO} is not defined, and this macro is defined to 1,
the DWARF 2 unwinder will be the default exception handling mechanism;
-otherwise, @code{setjmp}/@code{longjmp} will be used by default.
+otherwise, the @code{setjmp}/@code{longjmp}-based scheme will be used by
+default.
@end defmac
@defmac TARGET_UNWIND_INFO
these will be output by @code{TARGET_UNWIND_EMIT}.
@end defmac
-@deftypevar {Target Hook} bool TARGET_UNWID_TABLES_DEFAULT
+@deftypevar {Target Hook} bool TARGET_UNWIND_TABLES_DEFAULT
This variable should be set to @code{true} if the target ABI requires unwinding
tables even when exceptions are not used.
@end deftypevar
@defmac MUST_USE_SJLJ_EXCEPTIONS
This macro need only be defined if @code{DWARF2_UNWIND_INFO} is
runtime-variable. In that case, @file{except.h} cannot correctly
-determine the corresponding definition of
-@code{MUST_USE_SJLJ_EXCEPTIONS}, so the target must provide it directly.
+determine the corresponding definition of @code{MUST_USE_SJLJ_EXCEPTIONS},
+so the target must provide it directly.
+@end defmac
+
+@defmac DONT_USE_BUILTIN_SETJMP
+Define this macro to 1 if the @code{setjmp}/@code{longjmp}-based scheme
+should use the @code{setjmp}/@code{longjmp} functions from the C library
+instead of the @code{__builtin_setjmp}/@code{__builtin_longjmp} machinery.
@end defmac
@defmac DWARF_CIE_DATA_ALIGNMENT
If not defined, the default is to return @code{NULL_RTX}.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_INIT_DWARF_REG_SIZES_EXTRA (tree @var{address})
+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
+
@deftypefn {Target Hook} bool TARGET_ASM_TTYPE (rtx @var{sym})
This hook is used to output a reference from a frame unwinding table to
the type_info object identified by @var{sym}. It should return @code{true}
A C statement to output to the stdio stream @var{stream} an assembler
instruction to advance the location counter by @var{nbytes} bytes.
Those bytes should be zero when loaded. @var{nbytes} will be a C
-expression of type @code{int}.
+expression of type @code{unsigned HOST_WIDE_INT}.
@end defmac
@defmac ASM_NO_SKIP_IN_TEXT
@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
A C statement to issue assembly directives that create a difference
-between the two given labels, using an integer of the given size.
+@var{lab1} minus @var{lab2}, using an integer of the given @var{size}.
@end defmac
-@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label})
+@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label}, @var{section})
A C statement to issue assembly directives that create a
-section-relative reference to the given label, using an integer of the
-given size.
+section-relative reference to the given @var{label}, using an integer of the
+given @var{size}. The label is known to be defined in the given @var{section}.
@end defmac
@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
A C statement to issue assembly directives that create a self-relative
-reference to the given label, using an integer of the given size.
+reference to the given @var{label}, using an integer of the given @var{size}.
@end defmac
@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *@var{FILE}, int @var{size}, rtx @var{x})
@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_TRUNCATE (REAL_VALUE_TYPE @var{mode}, enum machine_mode @var{x})
Truncates the floating point value @var{x} to fit in @var{mode}. The
return value is still a full-size @code{REAL_VALUE_TYPE}, but it has an
-appropriate bit pattern to be output asa floating constant whose
+appropriate bit pattern to be output as a floating constant whose
precision accords with mode @var{mode}.
@end deftypefn
unit will not be COMDAT.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_CXX_LIBRARY_RTTI_COMDAT (void)
+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
+
@deftypefn {Target Hook} bool TARGET_CXX_USE_AEABI_ATEXIT (void)
This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)
should be used to register static destructors when @option{-fuse-cxa-atexit}
is in effect. The default is to return false to use @code{__cxa_atexit}.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT (void)
+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
+
@deftypefn {Target Hook} void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree @var{type})
@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just been
defined. Use this hook to make adjustments to the class (eg, tweak
unsigned one.
@end defmac
+@deftypefn {Target Hook} int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum machine_mode @var{mode})
+When @option{-ffast-math} is in effect, GCC tries to optimize
+divisions by the same divisor, by turning them into multiplications by
+the reciprocal. This target hook specifies the minimum number of divisions
+that should be there for GCC to perform the optimization for a variable
+of mode @var{mode}. The default implementation returns 3 if the machine
+has an instruction for the division, and 2 if it does not.
+@end deftypefn
+
@defmac MOVE_MAX
The maximum number of bytes that a single instruction can move quickly
between memory and registers or between two memory locations.
such cases may improve things.
@end defmac
+@deftypefn {Target Hook} int TARGET_MODE_REP_EXTENDED (enum machine_mode @var{mode}, enum machine_mode @var{rep_mode})
+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{mode_rep} so that @var{mode_rep} 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
with an integral mode and stored by a store-flag instruction
@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
-A C expression that evaluates to true if the architecture defines a value
-for @code{clz} or @code{ctz} with a zero operand. If so, @var{value}
-should be set to this value. If this macro is not defined, the value of
-@code{clz} or @code{ctz} is assumed to be undefined.
+A C expression that indicates whether the architecture defines a value
+for @code{clz} or @code{ctz} with a zero operand.
+A result of @code{0} indicates the value is undefined.
+If the value is defined for only the RTL expression, the macro should
+evaluate to @code{1}; if the value applies also to the corresponding optab
+entry (which is normally the case if it expands directly into
+the corresponding RTL), then the macro should evaluate to @code{2}.
+In the cases where the value is defined, @var{value} should be set to
+this value.
+
+If this macro is not defined, the value of @code{clz} or
+@code{ctz} at zero is assumed to be undefined.
This macro must be defined if the target's expansion for @code{ffs}
relies on a particular value to get correct results. Otherwise it
-is not necessary, though it may be used to optimize some corner cases.
+is not necessary, though it may be used to optimize some corner cases, and
+to provide a default expansion for the @code{ffs} optab.
Note that regardless of this macro the ``definedness'' of @code{clz}
and @code{ctz} at zero do @emph{not} extend to the builtin functions
@defmac FUNCTION_MODE
An alias for the machine mode used for memory references to functions
-being called, in @code{call} RTL expressions. On most machines this
-should be @code{QImode}.
+being called, in @code{call} RTL expressions. On most CISC machines,
+where an instruction can begin at any byte address, this should be
+@code{QImode}. On most RISC machines, where all instructions have fixed
+size and alignment, this should be a mode with the same size and alignment
+as the machine instruction words - typically @code{SImode} or @code{HImode}.
@end defmac
@defmac STDC_0_IN_SYSTEM_HEADERS
@code{c_register_pragma_with_expansion} but not on the arguments of
pragmas registered with @code{c_register_pragma}.
-For an example use of this routine, see @file{c4x.h} and the callback
-routines defined in @file{c4x-c.c}.
-
Note that the use of @code{pragma_lex} is specific to the C and C++
compilers. It will not work in the Java or Fortran compilers, or any
other language compilers for that matter. Thus if @code{pragma_lex} is going
@defmac TARGET_DEFAULT_PACK_STRUCT
If your target requires a structure packing default other than 0 (meaning
the machine default), define this macro to the necessary value (in bytes).
-This must be a value that would also valid to be used with
+This must be a value that would also be valid to use with
@samp{#pragma pack()} (that is, a small power of two).
@end defmac
+@findex #pragma
+@findex pragma
+@defmac HANDLE_PRAGMA_PUSH_POP_MACRO
+Define this macro if you want to support the Win32 style pragmas
+@samp{#pragma push_macro(macro-name-as-string)} and @samp{#pragma
+pop_macro(macro-name-as-string)}. The @samp{#pragma push_macro(
+macro-name-as-string)} pragma saves the named macro and via
+@samp{#pragma pop_macro(macro-name-as-string)} it will return to the
+previous value.
+@end defmac
+
+
@defmac DOLLARS_IN_IDENTIFIERS
Define this macro to control use of the character @samp{$} in
identifier names for the C family of languages. 0 means @samp{$} is
clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the
corresponding parameters to the asm and may be inspected to avoid
clobbering a register that is an input or output of the asm. You can use
-@code{decl_overlaps_hard_reg_set_p}, declared in @file{tree.h}, to test
+@code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test
for overlap with regards to asm-declared registers.
@end deftypefn
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.
+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.
+loops containing function calls or branch on table instructions.
@end deftypefn
@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
allocation.
@end deftypefn
+@deftypefn {Target Hook} int TARGET_UNSPEC_MAY_TRAP_P (const_rtx @var{x}, unsigned @var{flags})
+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
+
+@deftypefn {Target Hook} void TARGET_SET_CURRENT_FUNCTION (tree @var{decl})
+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.
+@end deftypefn
+
@defmac TARGET_OBJECT_SUFFIX
Define this macro to be a C string representing the suffix for object
files on your target machine. If you do not define this macro, GCC will
@end deftypefn
@deftypefn {Target Hook} const char *TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN (tree @var{typelist}, tree @var{funcdecl}, tree @var{val})
-If defined, this macro returns the diagnostic message when it is
-illegal to pass argument @var{val} to function @var{funcdecl}
+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
classes. By default, TARGET_USE_JCR_SECTION is defined to 1 if both
SUPPORTS_WEAK and TARGET_HAVE_NAMED_SECTIONS are true, else 0.
@end defmac
+
+@defmac OBJC_JBLEN
+This macro determines the size of the objective C jump buffer for the
+NeXT runtime. By default, OBJC_JBLEN is defined to an innocuous value.
+@end defmac
+
+@defmac LIBGCC2_UNWIND_ATTRIBUTE
+Define this macro if any target-specific attributes need to be attached
+to the functions in @file{libgcc} that provide low-level support for
+call stack unwinding. It is used in declarations in @file{unwind-generic.h}
+and the associated definitions of those functions.
+@end defmac
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