@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
-@c 2002, 2003, 2004, 2005, 2006, 2007 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.
@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
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})
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 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
@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
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
@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.
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
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
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{})
@c the above section title is WAY too long. maybe cut the part between
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.
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
@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
@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
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
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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