source: arduino-1-6-7/trunk/fuentes/arduino-ide-amd64/hardware/tools/avr/lib/gcc/avr/4.9.2/plugin/include/target.def @ 4837

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1/* Target hook definitions.
2   Copyright (C) 2001-2014 Free Software Foundation, Inc.
3
4   This program is free software; you can redistribute it and/or modify it
5   under the terms of the GNU General Public License as published by the
6   Free Software Foundation; either version 3, or (at your option) any
7   later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program; see the file COPYING3.  If not see
16   <http://www.gnu.org/licenses/>.
17
18   In other words, you are welcome to use, share and improve this program.
19   You are forbidden to forbid anyone else to use, share and improve
20   what you give them.   Help stamp out software-hoarding!  */
21
22/* See target-hooks-macros.h for details of macros that should be
23   provided by the including file, and how to use them here.  */
24#include "target-hooks-macros.h"
25
26#undef HOOK_TYPE
27#define HOOK_TYPE "Target Hook"
28
29HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
30
31/* Functions that output assembler for the target.  */
32#define HOOK_PREFIX "TARGET_ASM_"
33HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
34
35/* Opening and closing parentheses for asm expression grouping.  */
36DEFHOOKPOD
37(open_paren,
38 "These target hooks are C string constants, describing the syntax in the\n\
39assembler for grouping arithmetic expressions.  If not overridden, they\n\
40default to normal parentheses, which is correct for most assemblers.",
41 const char *, "(")
42DEFHOOKPODX (close_paren, const char *, ")")
43
44/* Assembler instructions for creating various kinds of integer object.  */
45DEFHOOKPOD
46(byte_op,
47 "@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
49@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
50@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
51@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
52@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
53@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
54@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
55These hooks specify assembly directives for creating certain kinds\n\
56of integer object.  The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
57byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
58aligned two-byte object, and so on.  Any of the hooks may be\n\
59@code{NULL}, indicating that no suitable directive is available.\n\
60\n\
61The compiler will print these strings at the start of a new line,\n\
62followed immediately by the object's initial value.  In most cases,\n\
63the string should contain a tab, a pseudo-op, and then another tab.",
64 const char *, "\t.byte\t")
65DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
66DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
67
68/* The maximum number of bytes to skip when applying
69   LABEL_ALIGN_AFTER_BARRIER.  */
70DEFHOOK
71(label_align_after_barrier_max_skip,
72 "The maximum number of bytes to skip before @var{label} when applying\n\
73@code{LABEL_ALIGN_AFTER_BARRIER}.  This works only if\n\
74@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
75 int, (rtx label),
76 default_label_align_after_barrier_max_skip)
77
78/* The maximum number of bytes to skip when applying
79   LOOP_ALIGN.  */
80DEFHOOK
81(loop_align_max_skip,
82 "The maximum number of bytes to skip when applying @code{LOOP_ALIGN} to\n\
83@var{label}.  This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is\n\
84defined.",
85 int, (rtx label),
86 default_loop_align_max_skip)
87
88/* The maximum number of bytes to skip when applying
89   LABEL_ALIGN.  */
90DEFHOOK
91(label_align_max_skip,
92 "The maximum number of bytes to skip when applying @code{LABEL_ALIGN}\n\
93to @var{label}.  This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}\n\
94is defined.",
95 int, (rtx label),
96 default_label_align_max_skip)
97
98/* The maximum number of bytes to skip when applying
99   JUMP_ALIGN.  */
100DEFHOOK
101(jump_align_max_skip,
102 "The maximum number of bytes to skip before @var{label} when applying\n\
103@code{JUMP_ALIGN}.  This works only if\n\
104@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
105 int, (rtx label),
106 default_jump_align_max_skip)
107
108/* Try to output the assembler code for an integer object whose
109   value is given by X.  SIZE is the size of the object in bytes and
110   ALIGNED_P indicates whether it is aligned.  Return true if
111   successful.  Only handles cases for which BYTE_OP, ALIGNED_OP
112   and UNALIGNED_OP are NULL.  */
113DEFHOOK
114(integer,
115 "The @code{assemble_integer} function uses this hook to output an\n\
116integer object.  @var{x} is the object's value, @var{size} is its size\n\
117in bytes and @var{aligned_p} indicates whether it is aligned.  The\n\
118function should return @code{true} if it was able to output the\n\
119object.  If it returns false, @code{assemble_integer} will try to\n\
120split the object into smaller parts.\n\
121\n\
122The default implementation of this hook will use the\n\
123@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
124when the relevant string is @code{NULL}.",
125 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
126    NULL.  */
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
129
130/* Output code that will globalize a label.  */
131DEFHOOK
132(globalize_label,
133 "This target hook is a function to output to the stdio stream\n\
134@var{stream} some commands that will make the label @var{name} global;\n\
135that is, available for reference from other files.\n\
136\n\
137The default implementation relies on a proper definition of\n\
138@code{GLOBAL_ASM_OP}.",
139 void, (FILE *stream, const char *name),
140 default_globalize_label)
141
142/* Output code that will globalize a declaration.  */
143DEFHOOK
144(globalize_decl_name,
145 "This target hook is a function to output to the stdio stream\n\
146@var{stream} some commands that will make the name associated with @var{decl}\n\
147global; that is, available for reference from other files.\n\
148\n\
149The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
150 void, (FILE *stream, tree decl), default_globalize_decl_name)
151
152/* Output code that will emit a label for unwind info, if this
153   target requires such labels.  Second argument is the decl the
154   unwind info is associated with, third is a boolean: true if
155   this is for exception handling, fourth is a boolean: true if
156   this is only a placeholder for an omitted FDE.  */
157DEFHOOK
158(emit_unwind_label,
159 "This target hook emits a label at the beginning of each FDE@.  It\n\
160should be defined on targets where FDEs need special labels, and it\n\
161should write the appropriate label, for the FDE associated with the\n\
162function declaration @var{decl}, to the stdio stream @var{stream}.\n\
163The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
164exception table.  The fourth argument, @var{empty}, is a boolean:\n\
165true if this is a placeholder label for an omitted FDE@.\n\
166\n\
167The default is that FDEs are not given nonlocal labels.",
168 void, (FILE *stream, tree decl, int for_eh, int empty),
169 default_emit_unwind_label)
170
171/* Output code that will emit a label to divide up the exception table.  */
172DEFHOOK
173(emit_except_table_label,
174 "This target hook emits a label at the beginning of the exception table.\n\
175It should be defined on targets where it is desirable for the table\n\
176to be broken up according to function.\n\
177\n\
178The default is that no label is emitted.",
179 void, (FILE *stream),
180 default_emit_except_table_label)
181
182/* Emit a directive for setting the personality for the function.  */
183DEFHOOK
184(emit_except_personality,
185 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
186 used to emit a directive to install a personality hook into the unwind\
187 info.  This hook should not be used if dwarf2 unwind info is used.",
188 void, (rtx personality),
189 NULL)
190
191/* Emit any directives required to unwind this instruction.  */
192DEFHOOK
193(unwind_emit,
194 "This target hook emits assembly directives required to unwind the\n\
195given instruction.  This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
196returns @code{UI_TARGET}.",
197 void, (FILE *stream, rtx insn),
198 NULL)
199
200DEFHOOKPOD
201(unwind_emit_before_insn,
202 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
203 the assembly for @var{insn} has been emitted, false if the hook should\
204 be called afterward.",
205 bool, true)
206
207/* Generate an internal label.
208   For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL.  */
209DEFHOOK_UNDOC
210(generate_internal_label,
211 "",
212 void, (char *buf, const char *prefix, unsigned long labelno),
213 default_generate_internal_label)
214
215/* Output an internal label.  */
216DEFHOOK
217(internal_label,
218 "A function to output to the stdio stream @var{stream} a label whose\n\
219name is made from the string @var{prefix} and the number @var{labelno}.\n\
220\n\
221It is absolutely essential that these labels be distinct from the labels\n\
222used for user-level functions and variables.  Otherwise, certain programs\n\
223will have name conflicts with internal labels.\n\
224\n\
225It is desirable to exclude internal labels from the symbol table of the\n\
226object file.  Most assemblers have a naming convention for labels that\n\
227should be excluded; on many systems, the letter @samp{L} at the\n\
228beginning of a label has this effect.  You should find out what\n\
229convention your system uses, and follow it.\n\
230\n\
231The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
232 void, (FILE *stream, const char *prefix, unsigned long labelno),
233 default_internal_label)
234
235/* Output label for the constant.  */
236DEFHOOK
237(declare_constant_name,
238 "A target hook to output to the stdio stream @var{file} any text necessary\n\
239for declaring the name @var{name} of a constant which is being defined.  This\n\
240target hook is responsible for outputting the label definition (perhaps using\n\
241@code{assemble_label}).  The argument @var{exp} is the value of the constant,\n\
242and @var{size} is the size of the constant in bytes.  The @var{name}\n\
243will be an internal label.\n\
244\n\
245The default version of this target hook, define the @var{name} in the\n\
246usual manner as a label (by means of @code{assemble_label}).\n\
247\n\
248You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
249 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
250 default_asm_declare_constant_name)
251
252/* Emit a ttype table reference to a typeinfo object.  */
253DEFHOOK
254(ttype,
255 "This hook is used to output a reference from a frame unwinding table to\n\
256the type_info object identified by @var{sym}.  It should return @code{true}\n\
257if the reference was output.  Returning @code{false} will cause the\n\
258reference to be output using the normal Dwarf2 routines.",
259 bool, (rtx sym),
260 hook_bool_rtx_false)
261
262/* Emit an assembler directive to set visibility for the symbol
263   associated with the tree decl.  */
264DEFHOOK
265(assemble_visibility,
266 "This target hook is a function to output to @var{asm_out_file} some\n\
267commands that will make the symbol(s) associated with @var{decl} have\n\
268hidden, protected or internal visibility as specified by @var{visibility}.",
269 void, (tree decl, int visibility),
270 default_assemble_visibility)
271
272/* Output the assembler code for entry to a function.  */
273DEFHOOK
274(function_prologue,
275 "If defined, a function that outputs the assembler code for entry to a\n\
276function.  The prologue is responsible for setting up the stack frame,\n\
277initializing the frame pointer register, saving registers that must be\n\
278saved, and allocating @var{size} additional bytes of storage for the\n\
279local variables.  @var{size} is an integer.  @var{file} is a stdio\n\
280stream to which the assembler code should be output.\n\
281\n\
282The label for the beginning of the function need not be output by this\n\
283macro.  That has already been done when the macro is run.\n\
284\n\
285@findex regs_ever_live\n\
286To determine which registers to save, the macro can refer to the array\n\
287@code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
288@var{r} is used anywhere within the function.  This implies the function\n\
289prologue should save register @var{r}, provided it is not one of the\n\
290call-used registers.  (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
291@code{regs_ever_live}.)\n\
292\n\
293On machines that have ``register windows'', the function entry code does\n\
294not save on the stack the registers that are in the windows, even if\n\
295they are supposed to be preserved by function calls; instead it takes\n\
296appropriate steps to ``push'' the register stack, if any non-call-used\n\
297registers are used in the function.\n\
298\n\
299@findex frame_pointer_needed\n\
300On machines where functions may or may not have frame-pointers, the\n\
301function entry code must vary accordingly; it must set up the frame\n\
302pointer if one is wanted, and not otherwise.  To determine whether a\n\
303frame pointer is in wanted, the macro can refer to the variable\n\
304@code{frame_pointer_needed}.  The variable's value will be 1 at run\n\
305time in a function that needs a frame pointer.  @xref{Elimination}.\n\
306\n\
307The function entry code is responsible for allocating any stack space\n\
308required for the function.  This stack space consists of the regions\n\
309listed below.  In most cases, these regions are allocated in the\n\
310order listed, with the last listed region closest to the top of the\n\
311stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
312the highest address if it is not defined).  You can use a different order\n\
313for a machine if doing so is more convenient or required for\n\
314compatibility reasons.  Except in cases where required by standard\n\
315or by a debugger, there is no reason why the stack layout used by GCC\n\
316need agree with that used by other compilers for a machine.",
317 void, (FILE *file, HOST_WIDE_INT size),
318 default_function_pro_epilogue)
319
320/* Output the assembler code for end of prologue.  */
321DEFHOOK
322(function_end_prologue,
323 "If defined, a function that outputs assembler code at the end of a\n\
324prologue.  This should be used when the function prologue is being\n\
325emitted as RTL, and you have some extra assembler that needs to be\n\
326emitted.  @xref{prologue instruction pattern}.",
327 void, (FILE *file),
328 no_asm_to_stream)
329
330/* Output the assembler code for start of epilogue.  */
331DEFHOOK
332(function_begin_epilogue,
333 "If defined, a function that outputs assembler code at the start of an\n\
334epilogue.  This should be used when the function epilogue is being\n\
335emitted as RTL, and you have some extra assembler that needs to be\n\
336emitted.  @xref{epilogue instruction pattern}.",
337 void, (FILE *file),
338 no_asm_to_stream)
339
340/* Output the assembler code for function exit.  */
341DEFHOOK
342(function_epilogue,
343 "If defined, a function that outputs the assembler code for exit from a\n\
344function.  The epilogue is responsible for restoring the saved\n\
345registers and stack pointer to their values when the function was\n\
346called, and returning control to the caller.  This macro takes the\n\
347same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
348registers to restore are determined from @code{regs_ever_live} and\n\
349@code{CALL_USED_REGISTERS} in the same way.\n\
350\n\
351On some machines, there is a single instruction that does all the work\n\
352of returning from the function.  On these machines, give that\n\
353instruction the name @samp{return} and do not define the macro\n\
354@code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
355\n\
356Do not define a pattern named @samp{return} if you want the\n\
357@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used.  If you want the target\n\
358switches to control whether return instructions or epilogues are used,\n\
359define a @samp{return} pattern with a validity condition that tests the\n\
360target switches appropriately.  If the @samp{return} pattern's validity\n\
361condition is false, epilogues will be used.\n\
362\n\
363On machines where functions may or may not have frame-pointers, the\n\
364function exit code must vary accordingly.  Sometimes the code for these\n\
365two cases is completely different.  To determine whether a frame pointer\n\
366is wanted, the macro can refer to the variable\n\
367@code{frame_pointer_needed}.  The variable's value will be 1 when compiling\n\
368a function that needs a frame pointer.\n\
369\n\
370Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
371@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
372The C variable @code{current_function_is_leaf} is nonzero for such a\n\
373function.  @xref{Leaf Functions}.\n\
374\n\
375On some machines, some functions pop their arguments on exit while\n\
376others leave that for the caller to do.  For example, the 68020 when\n\
377given @option{-mrtd} pops arguments in functions that take a fixed\n\
378number of arguments.\n\
379\n\
380@findex pops_args\n\
381@findex crtl->args.pops_args\n\
382Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
383functions pop their own arguments.  @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
384needs to know what was decided.  The number of bytes of the current\n\
385function's arguments that this function should pop is available in\n\
386@code{crtl->args.pops_args}.  @xref{Scalar Return}.",
387 void, (FILE *file, HOST_WIDE_INT size),
388 default_function_pro_epilogue)
389
390/* Initialize target-specific sections.  */
391DEFHOOK
392(init_sections,
393 "Define this hook if you need to do something special to set up the\n\
394@file{varasm.c} sections, or if your target has some special sections\n\
395of its own that you need to create.\n\
396\n\
397GCC calls this hook after processing the command line, but before writing\n\
398any assembly code, and before calling any of the section-returning hooks\n\
399described below.",
400 void, (void),
401 hook_void_void)
402
403/* Tell assembler to change to section NAME with attributes FLAGS.
404   If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
405   which this section is associated.  */
406DEFHOOK
407(named_section,
408 "Output assembly directives to switch to section @var{name}.  The section\n\
409should have attributes as specified by @var{flags}, which is a bit mask\n\
410of the @code{SECTION_*} flags defined in @file{output.h}.  If @var{decl}\n\
411is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
412this section is associated.",
413 void, (const char *name, unsigned int flags, tree decl),
414 default_no_named_section)
415
416/* Return preferred text (sub)section for function DECL.
417   Main purpose of this function is to separate cold, normal and hot
418   functions. STARTUP is true when function is known to be used only
419   at startup (from static constructors or it is main()).
420   EXIT is true when function is known to be used only at exit
421   (from static destructors).
422   Return NULL if function should go to default text section.  */
423DEFHOOK
424(function_section,
425 "Return preferred text (sub)section for function @var{decl}.\n\
426Main purpose of this function is to separate cold, normal and hot\n\
427functions. @var{startup} is true when function is known to be used only\n\
428at startup (from static constructors or it is @code{main()}).\n\
429@var{exit} is true when function is known to be used only at exit\n\
430(from static destructors).\n\
431Return NULL if function should go to default text section.",
432 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
433 default_function_section)
434
435/* Output the assembler code for function exit.  */
436DEFHOOK
437(function_switched_text_sections,
438 "Used by the target to emit any assembler directives or additional\
439  labels needed when a function is partitioned between different\
440  sections.  Output should be written to @var{file}.  The function\
441  decl is available as @var{decl} and the new section is `cold' if\
442  @var{new_is_cold} is @code{true}.",
443 void, (FILE *file, tree decl, bool new_is_cold),
444 default_function_switched_text_sections)
445
446/* Return a mask describing how relocations should be treated when
447   selecting sections.  Bit 1 should be set if global relocations
448   should be placed in a read-write section; bit 0 should be set if
449   local relocations should be placed in a read-write section.  */
450DEFHOOK
451(reloc_rw_mask,
452 "Return a mask describing how relocations should be treated when\n\
453selecting sections.  Bit 1 should be set if global relocations\n\
454should be placed in a read-write section; bit 0 should be set if\n\
455local relocations should be placed in a read-write section.\n\
456\n\
457The default version of this function returns 3 when @option{-fpic}\n\
458is in effect, and 0 otherwise.  The hook is typically redefined\n\
459when the target cannot support (some kinds of) dynamic relocations\n\
460in read-only sections even in executables.",
461 int, (void),
462 default_reloc_rw_mask)
463
464 /* Return a section for EXP.  It may be a DECL or a constant.  RELOC
465    is nonzero if runtime relocations must be applied; bit 1 will be
466    set if the runtime relocations require non-local name resolution.
467    ALIGN is the required alignment of the data.  */
468DEFHOOK
469(select_section,
470 "Return the section into which @var{exp} should be placed.  You can\n\
471assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
472some sort.  @var{reloc} indicates whether the initial value of @var{exp}\n\
473requires link-time relocations.  Bit 0 is set when variable contains\n\
474local relocations only, while bit 1 is set for global relocations.\n\
475@var{align} is the constant alignment in bits.\n\
476\n\
477The default version of this function takes care of putting read-only\n\
478variables in @code{readonly_data_section}.\n\
479\n\
480See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
481 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
482 default_select_section)
483
484/* Return a section for X.  MODE is X's mode and ALIGN is its
485   alignment in bits.  */
486DEFHOOK
487(select_rtx_section,
488 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
489should be placed.  You can assume that @var{x} is some kind of\n\
490constant in RTL@.  The argument @var{mode} is redundant except in the\n\
491case of a @code{const_int} rtx.  @var{align} is the constant alignment\n\
492in bits.\n\
493\n\
494The default version of this function takes care of putting symbolic\n\
495constants in @code{flag_pic} mode in @code{data_section} and everything\n\
496else in @code{readonly_data_section}.",
497 section *, (enum machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
498 default_select_rtx_section)
499
500/* Select a unique section name for DECL.  RELOC is the same as
501   for SELECT_SECTION.  */
502DEFHOOK
503(unique_section,
504 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
505and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
506As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
507the initial value of @var{exp} requires link-time relocations.\n\
508\n\
509The default version of this function appends the symbol name to the\n\
510ELF section name that would normally be used for the symbol.  For\n\
511example, the function @code{foo} would be placed in @code{.text.foo}.\n\
512Whatever the actual target object format, this is often good enough.",
513 void, (tree decl, int reloc),
514 default_unique_section)
515
516/* Return the readonly data section associated with function DECL.  */
517DEFHOOK
518(function_rodata_section,
519 "Return the readonly data section associated with\n\
520@samp{DECL_SECTION_NAME (@var{decl})}.\n\
521The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
522the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
523if function is in @code{.text.name}, and the normal readonly-data section\n\
524otherwise.",
525 section *, (tree decl),
526 default_function_rodata_section)
527
528/* Nonnull if the target wants to override the default ".rodata" prefix
529   for mergeable data sections.  */
530DEFHOOKPOD
531(mergeable_rodata_prefix,
532 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
533section names for mergeable constant data.  Define this macro to override\n\
534the string if a different section name should be used.",
535 const char *, ".rodata")
536
537/* Return the section to be used for transactional memory clone tables.  */
538DEFHOOK
539(tm_clone_table_section,
540 "Return the section that should be used for transactional memory clone\
541  tables.",
542 section *, (void), default_clone_table_section)
543
544/* Output a constructor for a symbol with a given priority.  */
545DEFHOOK
546(constructor,
547 "If defined, a function that outputs assembler code to arrange to call\n\
548the function referenced by @var{symbol} at initialization time.\n\
549\n\
550Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
551no arguments and with no return value.  If the target supports initialization\n\
552priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
553otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
554\n\
555If this macro is not defined by the target, a suitable default will\n\
556be chosen if (1) the target supports arbitrary section names, (2) the\n\
557target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
558is not defined.",
559 void, (rtx symbol, int priority), NULL)
560
561/* Output a destructor for a symbol with a given priority.  */
562DEFHOOK
563(destructor,
564 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
565functions rather than initialization functions.",
566 void, (rtx symbol, int priority), NULL)
567
568/* Output the assembler code for a thunk function.  THUNK_DECL is the
569   declaration for the thunk function itself, FUNCTION is the decl for
570   the target function.  DELTA is an immediate constant offset to be
571   added to THIS.  If VCALL_OFFSET is nonzero, the word at
572   *(*this + vcall_offset) should be added to THIS.  */
573DEFHOOK
574(output_mi_thunk,
575 "A function that outputs the assembler code for a thunk\n\
576function, used to implement C++ virtual function calls with multiple\n\
577inheritance.  The thunk acts as a wrapper around a virtual function,\n\
578adjusting the implicit object parameter before handing control off to\n\
579the real function.\n\
580\n\
581First, emit code to add the integer @var{delta} to the location that\n\
582contains the incoming first argument.  Assume that this argument\n\
583contains a pointer, and is the one used to pass the @code{this} pointer\n\
584in C++.  This is the incoming argument @emph{before} the function prologue,\n\
585e.g.@: @samp{%o0} on a sparc.  The addition must preserve the values of\n\
586all other incoming arguments.\n\
587\n\
588Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
589made after adding @code{delta}.  In particular, if @var{p} is the\n\
590adjusted pointer, the following adjustment should be made:\n\
591\n\
592@smallexample\n\
593p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
594@end smallexample\n\
595\n\
596After the additions, emit code to jump to @var{function}, which is a\n\
597@code{FUNCTION_DECL}.  This is a direct pure jump, not a call, and does\n\
598not touch the return address.  Hence returning from @var{FUNCTION} will\n\
599return to whoever called the current @samp{thunk}.\n\
600\n\
601The effect must be as if @var{function} had been called directly with\n\
602the adjusted first argument.  This macro is responsible for emitting all\n\
603of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
604and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
605\n\
606The @var{thunk_fndecl} is redundant.  (@var{delta} and @var{function}\n\
607have already been extracted from it.)  It might possibly be useful on\n\
608some targets, but probably not.\n\
609\n\
610If you do not define this macro, the target-independent code in the C++\n\
611front end will generate a less efficient heavyweight thunk that calls\n\
612@var{function} instead of jumping to it.  The generic approach does\n\
613not support varargs.",
614 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
615        HOST_WIDE_INT vcall_offset, tree function),
616 NULL)
617
618/* Determine whether output_mi_thunk would succeed.  */
619/* ??? Ideally, this hook would not exist, and success or failure
620   would be returned from output_mi_thunk directly.  But there's
621   too much undo-able setup involved in invoking output_mi_thunk.
622   Could be fixed by making output_mi_thunk emit rtl instead of
623   text to the output file.  */
624DEFHOOK
625(can_output_mi_thunk,
626 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
627to output the assembler code for the thunk function specified by the\n\
628arguments it is passed, and false otherwise.  In the latter case, the\n\
629generic approach will be used by the C++ front end, with the limitations\n\
630previously exposed.",
631 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
632        HOST_WIDE_INT vcall_offset, const_tree function),
633 hook_bool_const_tree_hwi_hwi_const_tree_false)
634
635/* Output any boilerplate text needed at the beginning of a
636   translation unit.  */
637DEFHOOK
638(file_start,
639 "Output to @code{asm_out_file} any text which the assembler expects to\n\
640find at the beginning of a file.  The default behavior is controlled\n\
641by two flags, documented below.  Unless your target's assembler is\n\
642quite unusual, if you override the default, you should call\n\
643@code{default_file_start} at some point in your target hook.  This\n\
644lets other target files rely on these variables.",
645 void, (void),
646 default_file_start)
647
648/* Output any boilerplate text needed at the end of a translation unit.  */
649DEFHOOK
650(file_end,
651 "Output to @code{asm_out_file} any text which the assembler expects\n\
652to find at the end of a file.  The default is to output nothing.",
653 void, (void),
654 hook_void_void)
655
656/* Output any boilerplate text needed at the beginning of an
657   LTO output stream.  */
658DEFHOOK
659(lto_start,
660 "Output to @code{asm_out_file} any text which the assembler expects\n\
661to find at the start of an LTO section.  The default is to output\n\
662nothing.",
663 void, (void),
664 hook_void_void)
665
666/* Output any boilerplate text needed at the end of an
667   LTO output stream.  */
668DEFHOOK
669(lto_end,
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671to find at the end of an LTO section.  The default is to output\n\
672nothing.",
673 void, (void),
674 hook_void_void)
675
676/* Output any boilerplace text needed at the end of a
677   translation unit before debug and unwind info is emitted.  */
678DEFHOOK
679(code_end,
680 "Output to @code{asm_out_file} any text which is needed before emitting\n\
681unwind info and debug info at the end of a file.  Some targets emit\n\
682here PIC setup thunks that cannot be emitted at the end of file,\n\
683because they couldn't have unwind info then.  The default is to output\n\
684nothing.",
685 void, (void),
686 hook_void_void)
687
688/* Output an assembler pseudo-op to declare a library function name
689   external.  */
690DEFHOOK
691(external_libcall,
692 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
693pseudo-op to declare a library function name external.  The name of the\n\
694library function is given by @var{symref}, which is a @code{symbol_ref}.",
695 void, (rtx symref),
696 default_external_libcall)
697
698/* Output an assembler directive to mark decl live. This instructs
699   linker to not dead code strip this symbol.  */
700DEFHOOK
701(mark_decl_preserved,
702 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
703directive to annotate @var{symbol} as used.  The Darwin target uses the\n\
704.no_dead_code_strip directive.",
705 void, (const char *symbol),
706 hook_void_constcharptr)
707
708/* Output a record of the command line switches that have been passed.  */
709DEFHOOK
710(record_gcc_switches,
711 "Provides the target with the ability to record the gcc command line\n\
712switches that have been passed to the compiler, and options that are\n\
713enabled.  The @var{type} argument specifies what is being recorded.\n\
714It can take the following values:\n\
715\n\
716@table @gcctabopt\n\
717@item SWITCH_TYPE_PASSED\n\
718@var{text} is a command line switch that has been set by the user.\n\
719\n\
720@item SWITCH_TYPE_ENABLED\n\
721@var{text} is an option which has been enabled.  This might be as a\n\
722direct result of a command line switch, or because it is enabled by\n\
723default or because it has been enabled as a side effect of a different\n\
724command line switch.  For example, the @option{-O2} switch enables\n\
725various different individual optimization passes.\n\
726\n\
727@item SWITCH_TYPE_DESCRIPTIVE\n\
728@var{text} is either NULL or some descriptive text which should be\n\
729ignored.  If @var{text} is NULL then it is being used to warn the\n\
730target hook that either recording is starting or ending.  The first\n\
731time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
732warning is for start up and the second time the warning is for\n\
733wind down.  This feature is to allow the target hook to make any\n\
734necessary preparations before it starts to record switches and to\n\
735perform any necessary tidying up after it has finished recording\n\
736switches.\n\
737\n\
738@item SWITCH_TYPE_LINE_START\n\
739This option can be ignored by this target hook.\n\
740\n\
741@item  SWITCH_TYPE_LINE_END\n\
742This option can be ignored by this target hook.\n\
743@end table\n\
744\n\
745The hook's return value must be zero.  Other return values may be\n\
746supported in the future.\n\
747\n\
748By default this hook is set to NULL, but an example implementation is\n\
749provided for ELF based targets.  Called @var{elf_record_gcc_switches},\n\
750it records the switches as ASCII text inside a new, string mergeable\n\
751section in the assembler output file.  The name of the new section is\n\
752provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
753hook.",
754 int, (print_switch_type type, const char *text),
755 NULL)
756
757/* The name of the section that the example ELF implementation of
758   record_gcc_switches will use to store the information.  Target
759   specific versions of record_gcc_switches may or may not use
760   this information.  */
761DEFHOOKPOD
762(record_gcc_switches_section,
763 "This is the name of the section that will be created by the example\n\
764ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
765hook.",
766 const char *, ".GCC.command.line")
767
768/* Output the definition of a section anchor.  */
769DEFHOOK
770(output_anchor,
771 "Write the assembly code to define section anchor @var{x}, which is a\n\
772@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
773The hook is called with the assembly output position set to the beginning\n\
774of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
775\n\
776If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
777it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
778If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
779is @code{NULL}, which disables the use of section anchors altogether.",
780 void, (rtx x),
781 default_asm_output_anchor)
782
783DEFHOOK
784(output_ident,
785 "Output a string based on @var{name}, suitable for the @samp{#ident} \
786 directive, or the equivalent directive or pragma in non-C-family languages. \
787 If this hook is not defined, nothing is output for the @samp{#ident} \
788 directive.",
789 void, (const char *name),
790 hook_void_constcharptr)
791
792/* Output a DTP-relative reference to a TLS symbol.  */
793DEFHOOK
794(output_dwarf_dtprel,
795 "If defined, this target hook is a function which outputs a DTP-relative\n\
796reference to the given TLS symbol of the specified size.",
797 void, (FILE *file, int size, rtx x),
798 NULL)
799
800/* Some target machines need to postscan each insn after it is output.  */
801DEFHOOK
802(final_postscan_insn,
803 "If defined, this target hook is a function which is executed just after the\n\
804output of assembler code for @var{insn}, to change the mode of the assembler\n\
805if necessary.\n\
806\n\
807Here the argument @var{opvec} is the vector containing the operands\n\
808extracted from @var{insn}, and @var{noperands} is the number of\n\
809elements of the vector which contain meaningful data for this insn.\n\
810The contents of this vector are what was used to convert the insn\n\
811template into assembler code, so you can change the assembler mode\n\
812by checking the contents of the vector.",
813 void, (FILE *file, rtx insn, rtx *opvec, int noperands),
814 NULL)
815
816/* Emit the trampoline template.  This hook may be NULL.  */
817DEFHOOK
818(trampoline_template,
819 "This hook is called by @code{assemble_trampoline_template} to output,\n\
820on the stream @var{f}, assembler code for a block of data that contains\n\
821the constant parts of a trampoline.  This code should not include a\n\
822label---the label is taken care of automatically.\n\
823\n\
824If you do not define this hook, it means no template is needed\n\
825for the target.  Do not define this hook on systems where the block move\n\
826code to copy the trampoline into place would be larger than the code\n\
827to generate it on the spot.",
828 void, (FILE *f),
829 NULL)
830
831DEFHOOK
832(output_source_filename,
833 "Output COFF information or DWARF debugging information which indicates\
834 that filename @var{name} is the current source file to the stdio\
835 stream @var{file}.\n\
836 \n\
837 This target hook need not be defined if the standard form of output\
838 for the file format in use is appropriate.",
839 void ,(FILE *file, const char *name),
840 default_asm_output_source_filename)
841
842DEFHOOK
843(output_addr_const_extra,
844 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
845can't deal with, and output assembly code to @var{file} corresponding to\n\
846the pattern @var{x}.  This may be used to allow machine-dependent\n\
847@code{UNSPEC}s to appear within constants.\n\
848\n\
849If target hook fails to recognize a pattern, it must return @code{false},\n\
850so that a standard error message is printed.  If it prints an error message\n\
851itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
852return @code{true}.",
853 bool, (FILE *file, rtx x),
854 hook_bool_FILEptr_rtx_false)
855
856/* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
857   even though that is not reflected in the macro name to override their
858   initializers.  */
859#undef HOOK_PREFIX
860#define HOOK_PREFIX "TARGET_"
861
862/* Emit a machine-specific insn operand.  */
863/* ??? tm.texi only documents the old macro PRINT_OPERAND,
864   not this  hook, and uses a different name for the argument FILE.  */
865DEFHOOK_UNDOC
866(print_operand,
867 "",
868 void, (FILE *file, rtx x, int code),
869 default_print_operand)
870
871/* Emit a machine-specific memory address.  */
872/* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
873   not this  hook, and uses different argument names.  */
874DEFHOOK_UNDOC
875(print_operand_address,
876 "",
877 void, (FILE *file, rtx addr),
878 default_print_operand_address)
879
880/* Determine whether CODE is a valid punctuation character for the
881   `print_operand' hook.  */
882/* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
883   not this  hook.  */
884DEFHOOK_UNDOC
885(print_operand_punct_valid_p,
886 "",
887 bool ,(unsigned char code),
888 default_print_operand_punct_valid_p)
889
890/* Given a symbol name, perform same mangling as assemble_name and
891   ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE.  */
892DEFHOOK
893(mangle_assembler_name,
894 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
895 @code{assemble_name}, but in memory rather than to a file stream, returning\
896 result as an @code{IDENTIFIER_NODE}.  Required for correct LTO symtabs.  The\
897 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
898 then prepends the @code{USER_LABEL_PREFIX}, if any.",
899 tree, (const char *name),
900 default_mangle_assembler_name)
901
902HOOK_VECTOR_END (asm_out)
903
904/* Functions relating to instruction scheduling.  All of these
905   default to null pointers, which haifa-sched.c looks for and handles.  */
906#undef HOOK_PREFIX
907#define HOOK_PREFIX "TARGET_SCHED_"
908HOOK_VECTOR (TARGET_SCHED, sched)
909
910/* Given the current cost, COST, of an insn, INSN, calculate and
911   return a new cost based on its relationship to DEP_INSN through
912   the dependence LINK.  The default is to make no adjustment.  */
913DEFHOOK
914(adjust_cost,
915 "This function corrects the value of @var{cost} based on the\n\
916relationship between @var{insn} and @var{dep_insn} through the\n\
917dependence @var{link}.  It should return the new value.  The default\n\
918is to make no adjustment to @var{cost}.  This can be used for example\n\
919to specify to the scheduler using the traditional pipeline description\n\
920that an output- or anti-dependence does not incur the same cost as a\n\
921data-dependence.  If the scheduler using the automaton based pipeline\n\
922description, the cost of anti-dependence is zero and the cost of\n\
923output-dependence is maximum of one and the difference of latency\n\
924times of the first and the second insns.  If these values are not\n\
925acceptable, you could use the hook to modify them too.  See also\n\
926@pxref{Processor pipeline description}.",
927 int, (rtx insn, rtx link, rtx dep_insn, int cost), NULL)
928
929/* Adjust the priority of an insn as you see fit.  Returns the new priority.  */
930DEFHOOK
931(adjust_priority,
932 "This hook adjusts the integer scheduling priority @var{priority} of\n\
933@var{insn}.  It should return the new priority.  Increase the priority to\n\
934execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
935later.  Do not define this hook if you do not need to adjust the\n\
936scheduling priorities of insns.",
937 int, (rtx insn, int priority), NULL)
938
939/* Function which returns the maximum number of insns that can be
940   scheduled in the same machine cycle.  This must be constant
941   over an entire compilation.  The default is 1.  */
942DEFHOOK
943(issue_rate,
944 "This hook returns the maximum number of instructions that can ever\n\
945issue at the same time on the target machine.  The default is one.\n\
946Although the insn scheduler can define itself the possibility of issue\n\
947an insn on the same cycle, the value can serve as an additional\n\
948constraint to issue insns on the same simulated processor cycle (see\n\
949hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
950This value must be constant over the entire compilation.  If you need\n\
951it to vary depending on what the instructions are, you must use\n\
952@samp{TARGET_SCHED_VARIABLE_ISSUE}.",
953 int, (void), NULL)
954
955/* Calculate how much this insn affects how many more insns we
956   can emit this cycle.  Default is they all cost the same.  */
957DEFHOOK
958(variable_issue,
959 "This hook is executed by the scheduler after it has scheduled an insn\n\
960from the ready list.  It should return the number of insns which can\n\
961still be issued in the current cycle.  The default is\n\
962@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
963@code{USE}, which normally are not counted against the issue rate.\n\
964You should define this hook if some insns take more machine resources\n\
965than others, so that fewer insns can follow them in the same cycle.\n\
966@var{file} is either a null pointer, or a stdio stream to write any\n\
967debug output to.  @var{verbose} is the verbose level provided by\n\
968@option{-fsched-verbose-@var{n}}.  @var{insn} is the instruction that\n\
969was scheduled.",
970 int, (FILE *file, int verbose, rtx insn, int more), NULL)
971
972/* Initialize machine-dependent scheduling code.  */
973DEFHOOK
974(init,
975 "This hook is executed by the scheduler at the beginning of each block of\n\
976instructions that are to be scheduled.  @var{file} is either a null\n\
977pointer, or a stdio stream to write any debug output to.  @var{verbose}\n\
978is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
979@var{max_ready} is the maximum number of insns in the current scheduling\n\
980region that can be live at the same time.  This can be used to allocate\n\
981scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
982 void, (FILE *file, int verbose, int max_ready), NULL)
983
984/* Finalize machine-dependent scheduling code.  */
985DEFHOOK
986(finish,
987 "This hook is executed by the scheduler at the end of each block of\n\
988instructions that are to be scheduled.  It can be used to perform\n\
989cleanup of any actions done by the other scheduling hooks.  @var{file}\n\
990is either a null pointer, or a stdio stream to write any debug output\n\
991to.  @var{verbose} is the verbose level provided by\n\
992@option{-fsched-verbose-@var{n}}.",
993 void, (FILE *file, int verbose), NULL)
994
995 /* Initialize machine-dependent function wide scheduling code.  */
996DEFHOOK
997(init_global,
998 "This hook is executed by the scheduler after function level initializations.\n\
999@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1000@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1001@var{old_max_uid} is the maximum insn uid when scheduling begins.",
1002 void, (FILE *file, int verbose, int old_max_uid), NULL)
1003
1004/* Finalize machine-dependent function wide scheduling code.  */
1005DEFHOOK
1006(finish_global,
1007 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1008@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1009@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1010 void, (FILE *file, int verbose), NULL)
1011
1012/* Reorder insns in a machine-dependent fashion, in two different
1013       places.  Default does nothing.  */
1014DEFHOOK
1015(reorder,
1016 "This hook is executed by the scheduler after it has scheduled the ready\n\
1017list, to allow the machine description to reorder it (for example to\n\
1018combine two small instructions together on @samp{VLIW} machines).\n\
1019@var{file} is either a null pointer, or a stdio stream to write any\n\
1020debug output to.  @var{verbose} is the verbose level provided by\n\
1021@option{-fsched-verbose-@var{n}}.  @var{ready} is a pointer to the ready\n\
1022list of instructions that are ready to be scheduled.  @var{n_readyp} is\n\
1023a pointer to the number of elements in the ready list.  The scheduler\n\
1024reads the ready list in reverse order, starting with\n\
1025@var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0].  @var{clock}\n\
1026is the timer tick of the scheduler.  You may modify the ready list and\n\
1027the number of ready insns.  The return value is the number of insns that\n\
1028can issue this cycle; normally this is just @code{issue_rate}.  See also\n\
1029@samp{TARGET_SCHED_REORDER2}.",
1030 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)
1031
1032DEFHOOK
1033(reorder2,
1034 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time.  That\n\
1035function is called whenever the scheduler starts a new cycle.  This one\n\
1036is called once per iteration over a cycle, immediately after\n\
1037@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1038return the number of insns to be scheduled in the same cycle.  Defining\n\
1039this hook can be useful if there are frequent situations where\n\
1040scheduling one insn causes other insns to become ready in the same\n\
1041cycle.  These other insns can then be taken into account properly.",
1042 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)
1043
1044DEFHOOK
1045(macro_fusion_p,
1046 "This hook is used to check whether target platform supports macro fusion.",
1047 bool, (void), NULL)
1048
1049DEFHOOK
1050(macro_fusion_pair_p,
1051 "This hook is used to check whether two insns could be macro fused for\n\
1052target microarchitecture. If this hook returns true for the given insn pair\n\
1053(@var{condgen} and @var{condjmp}), scheduler will put them into a sched\n\
1054group, and they will not be scheduled apart.",
1055 bool, (rtx condgen, rtx condjmp), NULL)
1056
1057/* The following member value is a pointer to a function called
1058   after evaluation forward dependencies of insns in chain given
1059   by two parameter values (head and tail correspondingly).  */
1060DEFHOOK
1061(dependencies_evaluation_hook,
1062 "This hook is called after evaluation forward dependencies of insns in\n\
1063chain given by two parameter values (@var{head} and @var{tail}\n\
1064correspondingly) but before insns scheduling of the insn chain.  For\n\
1065example, it can be used for better insn classification if it requires\n\
1066analysis of dependencies.  This hook can use backward and forward\n\
1067dependencies of the insn scheduler because they are already\n\
1068calculated.",
1069 void, (rtx head, rtx tail), NULL)
1070
1071/* The values of the following four members are pointers to functions
1072   used to simplify the automaton descriptions.  dfa_pre_cycle_insn and
1073   dfa_post_cycle_insn give functions returning insns which are used to
1074   change the pipeline hazard recognizer state when the new simulated
1075   processor cycle correspondingly starts and finishes.  The function
1076   defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1077   used to initialize the corresponding insns.  The default values of
1078   the members result in not changing the automaton state when the
1079   new simulated processor cycle correspondingly starts and finishes.  */
1080
1081DEFHOOK
1082(init_dfa_pre_cycle_insn,
1083 "The hook can be used to initialize data used by the previous hook.",
1084 void, (void), NULL)
1085
1086DEFHOOK
1087(dfa_pre_cycle_insn,
1088 "The hook returns an RTL insn.  The automaton state used in the\n\
1089pipeline hazard recognizer is changed as if the insn were scheduled\n\
1090when the new simulated processor cycle starts.  Usage of the hook may\n\
1091simplify the automaton pipeline description for some @acronym{VLIW}\n\
1092processors.  If the hook is defined, it is used only for the automaton\n\
1093based pipeline description.  The default is not to change the state\n\
1094when the new simulated processor cycle starts.",
1095 rtx, (void), NULL)
1096
1097DEFHOOK
1098(init_dfa_post_cycle_insn,
1099 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1100used to initialize data used by the previous hook.",
1101 void, (void), NULL)
1102
1103DEFHOOK
1104(dfa_post_cycle_insn,
1105 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1106to changed the state as if the insn were scheduled when the new\n\
1107simulated processor cycle finishes.",
1108 rtx, (void), NULL)
1109
1110/* The values of the following two members are pointers to
1111   functions used to simplify the automaton descriptions.
1112   dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1113   immediately before and after cycle is advanced.  */
1114
1115DEFHOOK
1116(dfa_pre_advance_cycle,
1117 "The hook to notify target that the current simulated cycle is about to finish.\n\
1118The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1119to change the state in more complicated situations - e.g., when advancing\n\
1120state on a single insn is not enough.",
1121 void, (void), NULL)
1122
1123DEFHOOK
1124(dfa_post_advance_cycle,
1125 "The hook to notify target that new simulated cycle has just started.\n\
1126The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1127to change the state in more complicated situations - e.g., when advancing\n\
1128state on a single insn is not enough.",
1129 void, (void), NULL)
1130
1131/* The following member value is a pointer to a function returning value
1132   which defines how many insns in queue `ready' will we try for
1133   multi-pass scheduling.  If the member value is nonzero and the
1134   function returns positive value, the DFA based scheduler will make
1135   multi-pass scheduling for the first cycle.  In other words, we will
1136   try to choose ready insn which permits to start maximum number of
1137   insns on the same cycle.  */
1138DEFHOOK
1139(first_cycle_multipass_dfa_lookahead,
1140 "This hook controls better choosing an insn from the ready insn queue\n\
1141for the @acronym{DFA}-based insn scheduler.  Usually the scheduler\n\
1142chooses the first insn from the queue.  If the hook returns a positive\n\
1143value, an additional scheduler code tries all permutations of\n\
1144@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1145subsequent ready insns to choose an insn whose issue will result in\n\
1146maximal number of issued insns on the same cycle.  For the\n\
1147@acronym{VLIW} processor, the code could actually solve the problem of\n\
1148packing simple insns into the @acronym{VLIW} insn.  Of course, if the\n\
1149rules of @acronym{VLIW} packing are described in the automaton.\n\
1150\n\
1151This code also could be used for superscalar @acronym{RISC}\n\
1152processors.  Let us consider a superscalar @acronym{RISC} processor\n\
1153with 3 pipelines.  Some insns can be executed in pipelines @var{A} or\n\
1154@var{B}, some insns can be executed only in pipelines @var{B} or\n\
1155@var{C}, and one insn can be executed in pipeline @var{B}.  The\n\
1156processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1157@var{B}.  In this case, the 3rd insn will wait for freeing @var{B}\n\
1158until the next cycle.  If the scheduler issues the 3rd insn the first,\n\
1159the processor could issue all 3 insns per cycle.\n\
1160\n\
1161Actually this code demonstrates advantages of the automaton based\n\
1162pipeline hazard recognizer.  We try quickly and easy many insn\n\
1163schedules to choose the best one.\n\
1164\n\
1165The default is no multipass scheduling.",
1166 int, (void), NULL)
1167
1168/* The following member value is pointer to a function controlling
1169   what insns from the ready insn queue will be considered for the
1170   multipass insn scheduling.  If the hook returns zero for insn
1171   passed as the parameter, the insn will be not chosen to be issued.  */
1172DEFHOOK
1173(first_cycle_multipass_dfa_lookahead_guard,
1174 "\n\
1175This hook controls what insns from the ready insn queue will be\n\
1176considered for the multipass insn scheduling.  If the hook returns\n\
1177zero for @var{insn}, the insn will be not chosen to\n\
1178be issued.\n\
1179\n\
1180The default is that any ready insns can be chosen to be issued.",
1181 int, (rtx insn), NULL)
1182
1183/* This hook prepares the target for a new round of multipass
1184   scheduling.
1185   DATA is a pointer to target-specific data used for multipass scheduling.
1186   READY_TRY and N_READY represent the current state of search in the
1187   optimization space.  The target can filter out instructions that
1188   should not be tried during current round by setting corresponding
1189   elements in READY_TRY to non-zero.
1190   FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1191   scheduling on current cycle.  */
1192DEFHOOK
1193(first_cycle_multipass_begin,
1194 "This hook prepares the target backend for a new round of multipass\n\
1195scheduling.",
1196 void, (void *data, char *ready_try, int n_ready, bool first_cycle_insn_p),
1197 NULL)
1198
1199/* This hook is called when multipass scheduling evaluates instruction INSN.
1200   DATA is a pointer to target-specific data that can be used to record effects
1201   of INSN on CPU that are not described in DFA.
1202   READY_TRY and N_READY represent the current state of search in the
1203   optimization space.  The target can filter out instructions that
1204   should not be tried after issuing INSN by setting corresponding
1205   elements in READY_TRY to non-zero.
1206   INSN is the instruction being evaluated.
1207   PREV_DATA is a pointer to target-specific data corresponding
1208   to a state before issuing INSN.  */
1209DEFHOOK
1210(first_cycle_multipass_issue,
1211 "This hook is called when multipass scheduling evaluates instruction INSN.",
1212 void, (void *data, char *ready_try, int n_ready, rtx insn,
1213        const void *prev_data), NULL)
1214
1215/* This hook is called when multipass scheduling backtracks from evaluation of
1216   instruction corresponding to DATA.
1217   DATA is a pointer to target-specific data that stores the effects
1218   of instruction from which the algorithm backtracks on CPU that are not
1219   described in DFA.
1220   READY_TRY and N_READY represent the current state of search in the
1221   optimization space.  The target can filter out instructions that
1222   should not be tried after issuing INSN by setting corresponding
1223   elements in READY_TRY to non-zero.  */
1224DEFHOOK
1225(first_cycle_multipass_backtrack,
1226 "This is called when multipass scheduling backtracks from evaluation of\n\
1227an instruction.",
1228 void, (const void *data, char *ready_try, int n_ready), NULL)
1229
1230/* This hook notifies the target about the result of the concluded current
1231   round of multipass scheduling.
1232   DATA is a pointer.
1233   If DATA is non-NULL it points to target-specific data used for multipass
1234   scheduling which corresponds to instruction at the start of the chain of
1235   the winning solution.  DATA is NULL when multipass scheduling cannot find
1236   a good enough solution on current cycle and decides to retry later,
1237   usually after advancing the cycle count.  */
1238DEFHOOK
1239(first_cycle_multipass_end,
1240 "This hook notifies the target about the result of the concluded current\n\
1241round of multipass scheduling.",
1242 void, (const void *data), NULL)
1243
1244/* This hook is called to initialize target-specific data for multipass
1245   scheduling after it has been allocated.
1246   DATA is a pointer to target-specific data that stores the effects
1247   of instruction from which the algorithm backtracks on CPU that are not
1248   described in DFA.  */
1249DEFHOOK
1250(first_cycle_multipass_init,
1251 "This hook initializes target-specific data used in multipass scheduling.",
1252 void, (void *data), NULL)
1253
1254/* This hook is called to finalize target-specific data for multipass
1255   scheduling before it is deallocated.
1256   DATA is a pointer to target-specific data that stores the effects
1257   of instruction from which the algorithm backtracks on CPU that are not
1258   described in DFA.  */
1259DEFHOOK
1260(first_cycle_multipass_fini,
1261 "This hook finalizes target-specific data used in multipass scheduling.",
1262 void, (void *data), NULL)
1263
1264/* The following member value is pointer to a function called by
1265   the insn scheduler before issuing insn passed as the third
1266   parameter on given cycle.  If the hook returns nonzero, the
1267   insn is not issued on given processors cycle.  Instead of that,
1268   the processor cycle is advanced.  If the value passed through
1269   the last parameter is zero, the insn ready queue is not sorted
1270   on the new cycle start as usually.  The first parameter passes
1271   file for debugging output.  The second one passes the scheduler
1272   verbose level of the debugging output.  The forth and the fifth
1273   parameter values are correspondingly processor cycle on which
1274   the previous insn has been issued and the current processor cycle.  */
1275DEFHOOK
1276(dfa_new_cycle,
1277 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1278on cycle @var{clock}.  If the hook returns nonzero,\n\
1279@var{insn} is not issued on this processor cycle.  Instead,\n\
1280the processor cycle is advanced.  If *@var{sort_p}\n\
1281is zero, the insn ready queue is not sorted on the new cycle\n\
1282start as usually.  @var{dump} and @var{verbose} specify the file and\n\
1283verbosity level to use for debugging output.\n\
1284@var{last_clock} and @var{clock} are, respectively, the\n\
1285processor cycle on which the previous insn has been issued,\n\
1286and the current processor cycle.",
1287 int, (FILE *dump, int verbose, rtx insn, int last_clock,
1288       int clock, int *sort_p),
1289 NULL)
1290
1291/* The following member value is a pointer to a function called by the
1292   insn scheduler.  It should return true if there exists a dependence
1293   which is considered costly by the target, between the insn
1294   DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP).  The first parameter is
1295   the dep that represents the dependence between the two insns.  The
1296   second argument is the cost of the dependence as estimated by
1297   the scheduler.  The last argument is the distance in cycles
1298   between the already scheduled insn (first parameter) and the
1299   second insn (second parameter).  */
1300DEFHOOK
1301(is_costly_dependence,
1302 "This hook is used to define which dependences are considered costly by\n\
1303the target, so costly that it is not advisable to schedule the insns that\n\
1304are involved in the dependence too close to one another.  The parameters\n\
1305to this hook are as follows:  The first parameter @var{_dep} is the dependence\n\
1306being evaluated.  The second parameter @var{cost} is the cost of the\n\
1307dependence as estimated by the scheduler, and the third\n\
1308parameter @var{distance} is the distance in cycles between the two insns.\n\
1309The hook returns @code{true} if considering the distance between the two\n\
1310insns the dependence between them is considered costly by the target,\n\
1311and @code{false} otherwise.\n\
1312\n\
1313Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1314where (a) it's practically hopeless to predict the actual data/resource\n\
1315delays, however: (b) there's a better chance to predict the actual grouping\n\
1316that will be formed, and (c) correctly emulating the grouping can be very\n\
1317important.  In such targets one may want to allow issuing dependent insns\n\
1318closer to one another---i.e., closer than the dependence distance;  however,\n\
1319not in cases of ``costly dependences'', which this hooks allows to define.",
1320 bool, (struct _dep *_dep, int cost, int distance), NULL)
1321
1322DEFHOOK_UNDOC
1323(adjust_cost_2,
1324 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1325 return a new cost based on its relationship to @var{dep_insn} through the\
1326 dependence of weakness @var{dw}.  The default is to make no adjustment.",
1327 int, (rtx insn, int dep_type1, rtx dep_insn, int cost, unsigned int dw), NULL)
1328
1329/* The following member value is a pointer to a function called
1330   by the insn scheduler. This hook is called to notify the backend
1331   that new instructions were emitted.  */
1332DEFHOOK
1333(h_i_d_extended,
1334 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1335the instruction stream.  The hook notifies a target backend to extend its\n\
1336per instruction data structures.",
1337 void, (void), NULL)
1338
1339/* Next 5 functions are for multi-point scheduling.  */
1340
1341/* Allocate memory for scheduler context.  */
1342DEFHOOK
1343(alloc_sched_context,
1344 "Return a pointer to a store large enough to hold target scheduling context.",
1345 void *, (void), NULL)
1346
1347/* Fills the context from the local machine scheduler context.  */
1348DEFHOOK
1349(init_sched_context,
1350 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1351It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1352beginning of the block.  Otherwise, copy the current context into @var{tc}.",
1353 void, (void *tc, bool clean_p), NULL)
1354
1355/* Sets local machine scheduler context to a saved value.  */
1356DEFHOOK
1357(set_sched_context,
1358 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1359 void, (void *tc), NULL)
1360
1361/* Clears a scheduler context so it becomes like after init.  */
1362DEFHOOK
1363(clear_sched_context,
1364 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1365 void, (void *tc), NULL)
1366
1367/* Frees the scheduler context.  */
1368DEFHOOK
1369(free_sched_context,
1370 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1371 void, (void *tc), NULL)
1372
1373/* The following member value is a pointer to a function called
1374   by the insn scheduler.
1375   The first parameter is an instruction, the second parameter is the type
1376   of the requested speculation, and the third parameter is a pointer to the
1377   speculative pattern of the corresponding type (set if return value == 1).
1378   It should return
1379   -1, if there is no pattern, that will satisfy the requested speculation type,
1380   0, if current pattern satisfies the requested speculation type,
1381   1, if pattern of the instruction should be changed to the newly
1382   generated one.  */
1383DEFHOOK
1384(speculate_insn,
1385 "This hook is called by the insn scheduler when @var{insn} has only\n\
1386speculative dependencies and therefore can be scheduled speculatively.\n\
1387The hook is used to check if the pattern of @var{insn} has a speculative\n\
1388version and, in case of successful check, to generate that speculative\n\
1389pattern.  The hook should return 1, if the instruction has a speculative form,\n\
1390or @minus{}1, if it doesn't.  @var{request} describes the type of requested\n\
1391speculation.  If the return value equals 1 then @var{new_pat} is assigned\n\
1392the generated speculative pattern.",
1393 int, (rtx insn, unsigned int dep_status, rtx *new_pat), NULL)
1394
1395/* The following member value is a pointer to a function called
1396   by the insn scheduler.  It should return true if the check instruction
1397   passed as the parameter needs a recovery block.  */
1398DEFHOOK
1399(needs_block_p,
1400 "This hook is called by the insn scheduler during generation of recovery code\n\
1401for @var{insn}.  It should return @code{true}, if the corresponding check\n\
1402instruction should branch to recovery code, or @code{false} otherwise.",
1403 bool, (unsigned int dep_status), NULL)
1404
1405/* The following member value is a pointer to a function called
1406   by the insn scheduler.  It should return a pattern for the check
1407   instruction.
1408   The first parameter is a speculative instruction, the second parameter
1409   is the label of the corresponding recovery block (or null, if it is a
1410   simple check).  The third parameter is the kind of speculation that
1411   is being performed.  */
1412DEFHOOK
1413(gen_spec_check,
1414 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1415check instruction.  If @var{mutate_p} is zero, then @var{insn} is a\n\
1416speculative instruction for which the check should be generated.\n\
1417@var{label} is either a label of a basic block, where recovery code should\n\
1418be emitted, or a null pointer, when requested check doesn't branch to\n\
1419recovery code (a simple check).  If @var{mutate_p} is nonzero, then\n\
1420a pattern for a branchy check corresponding to a simple check denoted by\n\
1421@var{insn} should be generated.  In this case @var{label} can't be null.",
1422 rtx, (rtx insn, rtx label, unsigned int ds), NULL)
1423
1424/* The following member value is a pointer to a function controlling
1425   what insns from the ready insn queue will be considered for the
1426   multipass insn scheduling.  If the hook returns zero for the insn
1427   passed as the parameter, the insn will not be chosen to be
1428   issued.  This hook is used to discard speculative instructions,
1429   that stand at the first position of the ready list.  */
1430DEFHOOK
1431(first_cycle_multipass_dfa_lookahead_guard_spec,
1432 "This hook is used as a workaround for\n\
1433@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD} not being\n\
1434called on the first instruction of the ready list.  The hook is used to\n\
1435discard speculative instructions that stand first in the ready list from\n\
1436being scheduled on the current cycle.  If the hook returns @code{false},\n\
1437@var{insn} will not be chosen to be issued.\n\
1438For non-speculative instructions,\n\
1439the hook should always return @code{true}.  For example, in the ia64 backend\n\
1440the hook is used to cancel data speculative insns when the ALAT table\n\
1441is nearly full.",
1442 bool, (const_rtx insn), NULL)
1443
1444/* The following member value is a pointer to a function that provides
1445   information about the speculation capabilities of the target.
1446   The parameter is a pointer to spec_info variable.  */
1447DEFHOOK
1448(set_sched_flags,
1449 "This hook is used by the insn scheduler to find out what features should be\n\
1450enabled/used.\n\
1451The structure *@var{spec_info} should be filled in by the target.\n\
1452The structure describes speculation types that can be used in the scheduler.",
1453 void, (struct spec_info_def *spec_info), NULL)
1454
1455DEFHOOK_UNDOC
1456(get_insn_spec_ds,
1457 "Return speculation types of instruction @var{insn}.",
1458 unsigned int, (rtx insn), NULL)
1459
1460DEFHOOK_UNDOC
1461(get_insn_checked_ds,
1462 "Return speculation types that are checked for instruction @var{insn}",
1463 unsigned int, (rtx insn), NULL)
1464
1465DEFHOOK_UNDOC
1466(skip_rtx_p,
1467 "Return bool if rtx scanning should just skip current layer and\
1468 advance to the inner rtxes.",
1469 bool, (const_rtx x), NULL)
1470
1471/* The following member value is a pointer to a function that provides
1472   information about the target resource-based lower bound which is
1473   used by the swing modulo scheduler.  The parameter is a pointer
1474   to ddg variable.  */
1475DEFHOOK
1476(sms_res_mii,
1477 "This hook is called by the swing modulo scheduler to calculate a\n\
1478resource-based lower bound which is based on the resources available in\n\
1479the machine and the resources required by each instruction.  The target\n\
1480backend can use @var{g} to calculate such bound.  A very simple lower\n\
1481bound will be used in case this hook is not implemented: the total number\n\
1482of instructions divided by the issue rate.",
1483 int, (struct ddg *g), NULL)
1484
1485/* The following member value is a function that initializes dispatch
1486   schedling and adds instructions to dispatch window according to its
1487   parameters.  */
1488DEFHOOK
1489(dispatch_do,
1490"This hook is called by Haifa Scheduler.  It performs the operation specified\n\
1491in its second parameter.",
1492void, (rtx insn, int x),
1493hook_void_rtx_int)
1494
1495/* The following member value is a a function that returns true is
1496   dispatch schedling is supported in hardware and condition passed
1497   as the second parameter is true.  */
1498DEFHOOK
1499(dispatch,
1500"This hook is called by Haifa Scheduler.  It returns true if dispatch scheduling\n\
1501is supported in hardware and the condition specified in the parameter is true.",
1502bool, (rtx insn, int x),
1503hook_bool_rtx_int_false)
1504
1505DEFHOOKPOD
1506(exposed_pipeline,
1507"True if the processor has an exposed pipeline, which means that not just\n\
1508the order of instructions is important for correctness when scheduling, but\n\
1509also the latencies of operations.",
1510bool, false)
1511
1512/* The following member value is a function that returns number
1513   of operations reassociator should try to put in parallel for
1514   statements of the given type.  By default 1 is used.  */
1515DEFHOOK
1516(reassociation_width,
1517"This hook is called by tree reassociator to determine a level of\n\
1518parallelism required in output calculations chain.",
1519int, (unsigned int opc, enum machine_mode mode),
1520hook_int_uint_mode_1)
1521
1522HOOK_VECTOR_END (sched)
1523
1524/* Functions relating to OpenMP and Cilk Plus SIMD clones.  */
1525#undef HOOK_PREFIX
1526#define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1527HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1528
1529DEFHOOK
1530(compute_vecsize_and_simdlen,
1531"This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1532fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1533@var{simdlen} field if it was previously 0.\n\
1534The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1535or number of @var{vecsize_mangle} variants that should be emitted.",
1536int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1537
1538DEFHOOK
1539(adjust,
1540"This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1541to SIMD clone @var{node} if needed.",
1542void, (struct cgraph_node *), NULL)
1543
1544DEFHOOK
1545(usable,
1546"This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1547in vectorized loops in current function, or non-negative number if it is\n\
1548usable.  In that case, the smaller the number is, the more desirable it is\n\
1549to use it.",
1550int, (struct cgraph_node *), NULL)
1551
1552HOOK_VECTOR_END (simd_clone)
1553
1554/* Functions relating to vectorization.  */
1555#undef HOOK_PREFIX
1556#define HOOK_PREFIX "TARGET_VECTORIZE_"
1557HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1558
1559/* The following member value is a pointer to a function called
1560   by the vectorizer, and return the decl of the target builtin
1561   function.  */
1562DEFHOOK
1563(builtin_mask_for_load,
1564 "This hook should return the DECL of a function @var{f} that given an\n\
1565address @var{addr} as an argument returns a mask @var{m} that can be\n\
1566used to extract from two vectors the relevant data that resides in\n\
1567@var{addr} in case @var{addr} is not properly aligned.\n\
1568\n\
1569The autovectorizer, when vectorizing a load operation from an address\n\
1570@var{addr} that may be unaligned, will generate two vector loads from\n\
1571the two aligned addresses around @var{addr}. It then generates a\n\
1572@code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1573two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1574@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1575the third argument, @var{OFF}, defines how the data will be extracted\n\
1576from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1577@var{v2}; otherwise, the returned vector is composed from the last\n\
1578@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1579@var{OFF} elements of @var{v2}.\n\
1580\n\
1581If this hook is defined, the autovectorizer will generate a call\n\
1582to @var{f} (using the DECL tree that this hook returns) and will\n\
1583use the return value of @var{f} as the argument @var{OFF} to\n\
1584@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1585should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1586described above.\n\
1587If this hook is not defined, then @var{addr} will be used as\n\
1588the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1589log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1590 tree, (void), NULL)
1591
1592/* Returns a code for builtin that realizes vectorized version of
1593   function, or NULL_TREE if not available.  */
1594DEFHOOK
1595(builtin_vectorized_function,
1596 "This hook should return the decl of a function that implements the\n\
1597vectorized variant of the builtin function with builtin function code\n\
1598@var{code} or @code{NULL_TREE} if such a function is not available.\n\
1599The value of @var{fndecl} is the builtin function declaration.  The\n\
1600return type of the vectorized function shall be of vector type\n\
1601@var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1602 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1603 default_builtin_vectorized_function)
1604
1605/* Returns a function declaration for a builtin that realizes the
1606   vector conversion, or NULL_TREE if not available.  */
1607DEFHOOK
1608(builtin_conversion,
1609 "This hook should return the DECL of a function that implements conversion of the\n\
1610input vector of type @var{src_type} to type @var{dest_type}.\n\
1611The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1612specifies how the conversion is to be applied\n\
1613(truncation, rounding, etc.).\n\
1614\n\
1615If this hook is defined, the autovectorizer will use the\n\
1616@code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1617conversion. Otherwise, it will return @code{NULL_TREE}.",
1618 tree, (unsigned code, tree dest_type, tree src_type),
1619 default_builtin_vectorized_conversion)
1620
1621/* Cost of different vector/scalar statements in vectorization cost
1622   model. In case of misaligned vector loads and stores the cost depends
1623   on the data type and misalignment value.  */
1624DEFHOOK
1625(builtin_vectorization_cost,
1626 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1627For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1628misalignment value (@var{misalign}).",
1629 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1630 default_builtin_vectorization_cost)
1631
1632/* Return true if vector alignment is reachable (by peeling N
1633   iterations) for the given type.  */
1634DEFHOOK
1635(vector_alignment_reachable,
1636 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1637 bool, (const_tree type, bool is_packed),
1638 default_builtin_vector_alignment_reachable)
1639
1640/* Return true if a vector created for vec_perm_const is valid.
1641   A NULL indicates that all constants are valid permutations.  */
1642DEFHOOK
1643(vec_perm_const_ok,
1644 "Return true if a vector created for @code{vec_perm_const} is valid.",
1645 bool, (enum machine_mode, const unsigned char *sel),
1646 NULL)
1647
1648/* Return true if the target supports misaligned store/load of a
1649   specific factor denoted in the third parameter.  The last parameter
1650   is true if the access is defined in a packed struct.  */
1651DEFHOOK
1652(support_vector_misalignment,
1653 "This hook should return true if the target supports misaligned vector\n\
1654store/load of a specific factor denoted in the @var{misalignment}\n\
1655parameter.  The vector store/load should be of machine mode @var{mode} and\n\
1656the elements in the vectors should be of type @var{type}.  @var{is_packed}\n\
1657parameter is true if the memory access is defined in a packed struct.",
1658 bool,
1659 (enum machine_mode mode, const_tree type, int misalignment, bool is_packed),
1660 default_builtin_support_vector_misalignment)
1661
1662/* Return the builtin decl needed to load a vector of TYPE.  */
1663DEFHOOK
1664(builtin_tm_load,
1665 "This hook should return the built-in decl needed to load a vector of the "
1666 "given type within a transaction.",
1667 tree,
1668 (tree),
1669 default_builtin_tm_load_store)
1670
1671/* Return the builtin decl needed to store a vector of TYPE.  */
1672DEFHOOK
1673(builtin_tm_store,
1674 "This hook should return the built-in decl needed to store a vector of the "
1675 "given type within a transaction.",
1676 tree,
1677 (tree),
1678 default_builtin_tm_load_store)
1679
1680/* Returns the preferred mode for SIMD operations for the specified
1681   scalar mode.  */
1682DEFHOOK
1683(preferred_simd_mode,
1684 "This hook should return the preferred mode for vectorizing scalar\n\
1685mode @var{mode}.  The default is\n\
1686equal to @code{word_mode}, because the vectorizer can do some\n\
1687transformations even in absence of specialized @acronym{SIMD} hardware.",
1688 enum machine_mode,
1689 (enum machine_mode mode),
1690 default_preferred_simd_mode)
1691
1692/* Returns a mask of vector sizes to iterate over when auto-vectorizing
1693   after processing the preferred one derived from preferred_simd_mode.  */
1694DEFHOOK
1695(autovectorize_vector_sizes,
1696 "This hook should return a mask of sizes that should be iterated over\n\
1697after trying to autovectorize using the vector size derived from the\n\
1698mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1699The default is zero which means to not iterate over other vector sizes.",
1700 unsigned int,
1701 (void),
1702 default_autovectorize_vector_sizes)
1703
1704/* Target builtin that implements vector gather operation.  */
1705DEFHOOK
1706(builtin_gather,
1707 "Target builtin that implements vector gather operation.  @var{mem_vectype}\n\
1708is the vector type of the load and @var{index_type} is scalar type of\n\
1709the index, scaled by @var{scale}.\n\
1710The default is @code{NULL_TREE} which means to not vectorize gather\n\
1711loads.",
1712 tree,
1713 (const_tree mem_vectype, const_tree index_type, int scale),
1714 NULL)
1715
1716/* Target function to initialize the cost model for a loop or block.  */
1717DEFHOOK
1718(init_cost,
1719 "This hook should initialize target-specific data structures in preparation "
1720 "for modeling the costs of vectorizing a loop or basic block.  The default "
1721 "allocates three unsigned integers for accumulating costs for the prologue, "
1722 "body, and epilogue of the loop or basic block.  If @var{loop_info} is "
1723 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1724 "is being vectorized.",
1725 void *,
1726 (struct loop *loop_info),
1727 default_init_cost)
1728
1729/* Target function to record N statements of the given kind using the
1730   given vector type within the cost model data for the current loop or
1731    block.  */
1732DEFHOOK
1733(add_stmt_cost,
1734 "This hook should update the target-specific @var{data} in response to "
1735 "adding @var{count} copies of the given @var{kind} of statement to a "
1736 "loop or basic block.  The default adds the builtin vectorizer cost for "
1737 "the copies of the statement to the accumulator specified by @var{where}, "
1738 "(the prologue, body, or epilogue) and returns the amount added.  The "
1739 "return value should be viewed as a tentative cost that may later be "
1740 "revised.",
1741 unsigned,
1742 (void *data, int count, enum vect_cost_for_stmt kind,
1743  struct _stmt_vec_info *stmt_info, int misalign,
1744  enum vect_cost_model_location where),
1745 default_add_stmt_cost)
1746
1747/* Target function to calculate the total cost of the current vectorized
1748   loop or block.  */
1749DEFHOOK
1750(finish_cost,
1751 "This hook should complete calculations of the cost of vectorizing a loop "
1752 "or basic block based on @var{data}, and return the prologue, body, and "
1753 "epilogue costs as unsigned integers.  The default returns the value of "
1754 "the three accumulators.",
1755 void,
1756 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1757  unsigned *epilogue_cost),
1758 default_finish_cost)
1759
1760/* Function to delete target-specific cost modeling data.  */
1761DEFHOOK
1762(destroy_cost_data,
1763 "This hook should release @var{data} and any related data structures "
1764 "allocated by TARGET_VECTORIZE_INIT_COST.  The default releases the "
1765 "accumulator.",
1766 void,
1767 (void *data),
1768 default_destroy_cost_data)
1769
1770HOOK_VECTOR_END (vectorize)
1771
1772#undef HOOK_PREFIX
1773#define HOOK_PREFIX "TARGET_"
1774
1775/* Allow target specific overriding of option settings after options have
1776  been changed by an attribute or pragma or when it is reset at the
1777  end of the code affected by an attribute or pragma.  */
1778DEFHOOK
1779(override_options_after_change,
1780 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1781but is called when the optimize level is changed via an attribute or\n\
1782pragma or when it is reset at the end of the code affected by the\n\
1783attribute or pragma.  It is not called at the beginning of compilation\n\
1784when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1785actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1786@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1787 void, (void),
1788 hook_void_void)
1789
1790DEFHOOK_UNDOC
1791(eh_return_filter_mode,
1792 "Return machine mode for filter value.",
1793 enum machine_mode, (void),
1794 default_eh_return_filter_mode)
1795
1796/* Return machine mode for libgcc expanded cmp instructions.  */
1797DEFHOOK
1798(libgcc_cmp_return_mode,
1799 "This target hook should return the mode to be used for the return value\n\
1800of compare instructions expanded to libgcc calls.  If not defined\n\
1801@code{word_mode} is returned which is the right choice for a majority of\n\
1802targets.",
1803 enum machine_mode, (void),
1804 default_libgcc_cmp_return_mode)
1805
1806/* Return machine mode for libgcc expanded shift instructions.  */
1807DEFHOOK
1808(libgcc_shift_count_mode,
1809 "This target hook should return the mode to be used for the shift count operand\n\
1810of shift instructions expanded to libgcc calls.  If not defined\n\
1811@code{word_mode} is returned which is the right choice for a majority of\n\
1812targets.",
1813 enum machine_mode, (void),
1814 default_libgcc_shift_count_mode)
1815
1816/* Return machine mode to be used for _Unwind_Word type.  */
1817DEFHOOK
1818(unwind_word_mode,
1819 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
1820The default is to use @code{word_mode}.",
1821 enum machine_mode, (void),
1822 default_unwind_word_mode)
1823
1824/* Given two decls, merge their attributes and return the result.  */
1825DEFHOOK
1826(merge_decl_attributes,
1827 "Define this target hook if the merging of decl attributes needs special\n\
1828handling.  If defined, the result is a list of the combined\n\
1829@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
1830@var{newdecl} is a duplicate declaration of @var{olddecl}.  Examples of\n\
1831when this is needed are when one attribute overrides another, or when an\n\
1832attribute is nullified by a subsequent definition.  This function may\n\
1833call @code{merge_attributes} to handle machine-independent merging.\n\
1834\n\
1835@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
1836If the only target-specific handling you require is @samp{dllimport}\n\
1837for Microsoft Windows targets, you should define the macro\n\
1838@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}.  The compiler\n\
1839will then define a function called\n\
1840@code{merge_dllimport_decl_attributes} which can then be defined as\n\
1841the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}.  You can also\n\
1842add @code{handle_dll_attribute} in the attribute table for your port\n\
1843to perform initial processing of the @samp{dllimport} and\n\
1844@samp{dllexport} attributes.  This is done in @file{i386/cygwin.h} and\n\
1845@file{i386/i386.c}, for example.",
1846 tree, (tree olddecl, tree newdecl),
1847 merge_decl_attributes)
1848
1849/* Given two types, merge their attributes and return the result.  */
1850DEFHOOK
1851(merge_type_attributes,
1852 "Define this target hook if the merging of type attributes needs special\n\
1853handling.  If defined, the result is a list of the combined\n\
1854@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}.  It is assumed\n\
1855that @code{comptypes} has already been called and returned 1.  This\n\
1856function may call @code{merge_attributes} to handle machine-independent\n\
1857merging.",
1858 tree, (tree type1, tree type2),
1859 merge_type_attributes)
1860
1861/* Table of machine attributes and functions to handle them.
1862   Ignored if NULL.  */
1863DEFHOOKPOD
1864(attribute_table,
1865 "If defined, this target hook points to an array of @samp{struct\n\
1866attribute_spec} (defined in @file{tree.h}) specifying the machine\n\
1867specific attributes for this target and some of the restrictions on the\n\
1868entities to which these attributes are applied and the arguments they\n\
1869take.",
1870 const struct attribute_spec *, NULL)
1871
1872/* Return true iff attribute NAME expects a plain identifier as its first
1873   argument.  */
1874DEFHOOK
1875(attribute_takes_identifier_p,
1876 "If defined, this target hook is a function which returns true if the\n\
1877machine-specific attribute named @var{name} expects an identifier\n\
1878given as its first argument to be passed on as a plain identifier, not\n\
1879subjected to name lookup.  If this is not defined, the default is\n\
1880false for all machine-specific attributes.",
1881 bool, (const_tree name),
1882 hook_bool_const_tree_false)
1883
1884/* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
1885   one if they are compatible and two if they are nearly compatible
1886   (which causes a warning to be generated).  */
1887DEFHOOK
1888(comp_type_attributes,
1889 "If defined, this target hook is a function which returns zero if the attributes on\n\
1890@var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
1891and two if they are nearly compatible (which causes a warning to be\n\
1892generated).  If this is not defined, machine-specific attributes are\n\
1893supposed always to be compatible.",
1894 int, (const_tree type1, const_tree type2),
1895 hook_int_const_tree_const_tree_1)
1896
1897/* Assign default attributes to the newly defined TYPE.  */
1898DEFHOOK
1899(set_default_type_attributes,
1900 "If defined, this target hook is a function which assigns default attributes to\n\
1901the newly defined @var{type}.",
1902 void, (tree type),
1903 hook_void_tree)
1904
1905/* Insert attributes on the newly created DECL.  */
1906DEFHOOK
1907(insert_attributes,
1908 "Define this target hook if you want to be able to add attributes to a decl\n\
1909when it is being created.  This is normally useful for back ends which\n\
1910wish to implement a pragma by using the attributes which correspond to\n\
1911the pragma's effect.  The @var{node} argument is the decl which is being\n\
1912created.  The @var{attr_ptr} argument is a pointer to the attribute list\n\
1913for this decl.  The list itself should not be modified, since it may be\n\
1914shared with other decls, but attributes may be chained on the head of\n\
1915the list and @code{*@var{attr_ptr}} modified to point to the new\n\
1916attributes, or a copy of the list may be made if further changes are\n\
1917needed.",
1918 void, (tree node, tree *attr_ptr),
1919 hook_void_tree_treeptr)
1920
1921/* Return true if FNDECL (which has at least one machine attribute)
1922   can be inlined despite its machine attributes, false otherwise.  */
1923DEFHOOK
1924(function_attribute_inlinable_p,
1925 "@cindex inlining\n\
1926This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
1927into the current function, despite its having target-specific\n\
1928attributes, @code{false} otherwise.  By default, if a function has a\n\
1929target specific attribute attached to it, it will not be inlined.",
1930 bool, (const_tree fndecl),
1931 hook_bool_const_tree_false)
1932
1933/* Return true if bitfields in RECORD_TYPE should follow the
1934   Microsoft Visual C++ bitfield layout rules.  */
1935DEFHOOK
1936(ms_bitfield_layout_p,
1937 "This target hook returns @code{true} if bit-fields in the given\n\
1938@var{record_type} are to be laid out following the rules of Microsoft\n\
1939Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
1940unit with the previous bit-field if their underlying types have\n\
1941different sizes, and the bit-field will be aligned to the highest\n\
1942alignment of the underlying types of itself and of the previous\n\
1943bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
1944the whole enclosing structure, even if it is unnamed; except that\n\
1945(iii) a zero-sized bit-field will be disregarded unless it follows\n\
1946another bit-field of nonzero size.  If this hook returns @code{true},\n\
1947other macros that control bit-field layout are ignored.\n\
1948\n\
1949When a bit-field is inserted into a packed record, the whole size\n\
1950of the underlying type is used by one or more same-size adjacent\n\
1951bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
1952and any additional adjacent long bit-fields are packed into the same\n\
1953chunk of 32 bits.  However, if the size changes, a new field of that\n\
1954size is allocated).  In an unpacked record, this is the same as using\n\
1955alignment, but not equivalent when packing.\n\
1956\n\
1957If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
1958the latter will take precedence.  If @samp{__attribute__((packed))} is\n\
1959used on a single field when MS bit-fields are in use, it will take\n\
1960precedence for that field, but the alignment of the rest of the structure\n\
1961may affect its placement.",
1962 bool, (const_tree record_type),
1963 hook_bool_const_tree_false)
1964
1965/* For now this is only an interface to WORDS_BIG_ENDIAN for
1966   target-independent code like the front ends, need performance testing
1967   before switching completely to the target hook.  */
1968DEFHOOK_UNDOC
1969(words_big_endian,
1970 "",
1971 bool, (void),
1972 targhook_words_big_endian)
1973
1974/* Likewise for FLOAT_WORDS_BIG_ENDIAN.  */
1975DEFHOOK_UNDOC
1976(float_words_big_endian,
1977 "",
1978 bool, (void),
1979 targhook_float_words_big_endian)
1980
1981DEFHOOK
1982(float_exceptions_rounding_supported_p,
1983 "Returns true if the target supports IEEE 754 floating-point exceptions\
1984 and rounding modes, false otherwise.  This is intended to relate to the\
1985 @code{float} and @code{double} types, but not necessarily @code{long double}.\
1986 By default, returns true if the @code{adddf3} instruction pattern is\
1987 available and false otherwise, on the assumption that hardware floating\
1988 point supports exceptions and rounding modes but software floating point\
1989 does not.",
1990 bool, (void),
1991 default_float_exceptions_rounding_supported_p)
1992
1993/* True if the target supports decimal floating point.  */
1994DEFHOOK
1995(decimal_float_supported_p,
1996 "Returns true if the target supports decimal floating point.",
1997 bool, (void),
1998 default_decimal_float_supported_p)
1999
2000/* True if the target supports fixed-point.  */
2001DEFHOOK
2002(fixed_point_supported_p,
2003 "Returns true if the target supports fixed-point arithmetic.",
2004 bool, (void),
2005 default_fixed_point_supported_p)
2006
2007/* Return true if anonymous bitfields affect structure alignment.  */
2008DEFHOOK
2009(align_anon_bitfield,
2010 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2011whether unnamed bitfields affect the alignment of the containing\n\
2012structure.  The hook should return true if the structure should inherit\n\
2013the alignment requirements of an unnamed bitfield's type.",
2014 bool, (void),
2015 hook_bool_void_false)
2016
2017/* Return true if volatile bitfields should use the narrowest type possible.
2018   Return false if they should use the container type.  */
2019DEFHOOK
2020(narrow_volatile_bitfield,
2021 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2022should use the narrowest mode possible.  It should return @code{false} if\n\
2023these accesses should use the bitfield container type.\n\
2024\n\
2025The default is @code{false}.",
2026 bool, (void),
2027 hook_bool_void_false)
2028
2029/* Set up target-specific built-in functions.  */
2030DEFHOOK
2031(init_builtins,
2032 "Define this hook if you have any machine-specific built-in functions\n\
2033that need to be defined.  It should be a function that performs the\n\
2034necessary setup.\n\
2035\n\
2036Machine specific built-in functions can be useful to expand special machine\n\
2037instructions that would otherwise not normally be generated because\n\
2038they have no equivalent in the source language (for example, SIMD vector\n\
2039instructions or prefetch instructions).\n\
2040\n\
2041To create a built-in function, call the function\n\
2042@code{lang_hooks.builtin_function}\n\
2043which is defined by the language front end.  You can use any type nodes set\n\
2044up by @code{build_common_tree_nodes};\n\
2045only language front ends that use those two functions will call\n\
2046@samp{TARGET_INIT_BUILTINS}.",
2047 void, (void),
2048 hook_void_void)
2049
2050/* Initialize (if INITIALIZE_P is true) and return the target-specific
2051   built-in function decl for CODE.
2052   Return NULL if that is not possible.  Return error_mark_node if CODE
2053   is outside of the range of valid target builtin function codes.  */
2054DEFHOOK
2055(builtin_decl,
2056 "Define this hook if you have any machine-specific built-in functions\n\
2057that need to be defined.  It should be a function that returns the\n\
2058builtin function declaration for the builtin function code @var{code}.\n\
2059If there is no such builtin and it cannot be initialized at this time\n\
2060if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2061If @var{code} is out of range the function should return\n\
2062@code{error_mark_node}.",
2063 tree, (unsigned code, bool initialize_p), NULL)
2064
2065/* Expand a target-specific builtin.  */
2066DEFHOOK
2067(expand_builtin,
2068 "\n\
2069Expand a call to a machine specific built-in function that was set up by\n\
2070@samp{TARGET_INIT_BUILTINS}.  @var{exp} is the expression for the\n\
2071function call; the result should go to @var{target} if that is\n\
2072convenient, and have mode @var{mode} if that is convenient.\n\
2073@var{subtarget} may be used as the target for computing one of\n\
2074@var{exp}'s operands.  @var{ignore} is nonzero if the value is to be\n\
2075ignored.  This function should return the result of the call to the\n\
2076built-in function.",
2077 rtx,
2078 (tree exp, rtx target, rtx subtarget, enum machine_mode mode, int ignore),
2079 default_expand_builtin)
2080
2081/* Select a replacement for a target-specific builtin.  This is done
2082   *before* regular type checking, and so allows the target to
2083   implement a crude form of function overloading.  The result is a
2084   complete expression that implements the operation.  PARAMS really
2085   has type VEC(tree,gc)*, but we don't want to include tree.h here.  */
2086DEFHOOK
2087(resolve_overloaded_builtin,
2088 "Select a replacement for a machine specific built-in function that\n\
2089was set up by @samp{TARGET_INIT_BUILTINS}.  This is done\n\
2090@emph{before} regular type checking, and so allows the target to\n\
2091implement a crude form of function overloading.  @var{fndecl} is the\n\
2092declaration of the built-in function.  @var{arglist} is the list of\n\
2093arguments passed to the built-in function.  The result is a\n\
2094complete expression that implements the operation, usually\n\
2095another @code{CALL_EXPR}.\n\
2096@var{arglist} really has type @samp{VEC(tree,gc)*}",
2097 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2098
2099/* Fold a target-specific builtin to a tree valid for both GIMPLE
2100   and GENERIC.  */
2101DEFHOOK
2102(fold_builtin,
2103 "Fold a call to a machine specific built-in function that was set up by\n\
2104@samp{TARGET_INIT_BUILTINS}.  @var{fndecl} is the declaration of the\n\
2105built-in function.  @var{n_args} is the number of arguments passed to\n\
2106the function; the arguments themselves are pointed to by @var{argp}.\n\
2107The result is another tree, valid for both GIMPLE and GENERIC,\n\
2108containing a simplified expression for the call's result.  If\n\
2109@var{ignore} is true the value will be ignored.",
2110 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2111 hook_tree_tree_int_treep_bool_null)
2112
2113/* Fold a target-specific builtin to a valid GIMPLE tree.  */
2114DEFHOOK
2115(gimple_fold_builtin,
2116 "Fold a call to a machine specific built-in function that was set up\n\
2117by @samp{TARGET_INIT_BUILTINS}.  @var{gsi} points to the gimple\n\
2118statement holding the function call.  Returns true if any change\n\
2119was made to the GIMPLE stream.",
2120 bool, (gimple_stmt_iterator *gsi),
2121 hook_bool_gsiptr_false)
2122
2123/* Target hook is used to compare the target attributes in two functions to
2124   determine which function's features get higher priority.  This is used
2125   during function multi-versioning to figure out the order in which two
2126   versions must be dispatched.  A function version with a higher priority
2127   is checked for dispatching earlier.  DECL1 and DECL2 are
2128   the two function decls that will be compared. It returns positive value
2129   if DECL1 is higher priority,  negative value if DECL2 is higher priority
2130   and 0 if they are the same. */
2131DEFHOOK
2132(compare_version_priority,
2133 "This hook is used to compare the target attributes in two functions to\n\
2134determine which function's features get higher priority.  This is used\n\
2135during function multi-versioning to figure out the order in which two\n\
2136versions must be dispatched.  A function version with a higher priority\n\
2137is checked for dispatching earlier.  @var{decl1} and @var{decl2} are\n\
2138 the two function decls that will be compared.",
2139 int, (tree decl1, tree decl2), NULL)
2140
2141/*  Target hook is used to generate the dispatcher logic to invoke the right
2142    function version at run-time for a given set of function versions.
2143    ARG points to the callgraph node of the dispatcher function whose body
2144    must be generated.  */
2145DEFHOOK
2146(generate_version_dispatcher_body,
2147 "This hook is used to generate the dispatcher logic to invoke the right\n\
2148function version at run-time for a given set of function versions.\n\
2149@var{arg} points to the callgraph node of the dispatcher function whose\n\
2150body must be generated.",
2151 tree, (void *arg), NULL)
2152
2153/* Target hook is used to get the dispatcher function for a set of function
2154   versions.  The dispatcher function is called to invoke the right function
2155   version at run-time.  DECL is one version from a set of semantically
2156   identical versions.  */
2157DEFHOOK
2158(get_function_versions_dispatcher,
2159 "This hook is used to get the dispatcher function for a set of function\n\
2160versions.  The dispatcher function is called to invoke the right function\n\
2161version at run-time. @var{decl} is one version from a set of semantically\n\
2162identical versions.",
2163 tree, (void *decl), NULL)
2164
2165/* Returns a code for a target-specific builtin that implements
2166   reciprocal of the function, or NULL_TREE if not available.  */
2167DEFHOOK
2168(builtin_reciprocal,
2169 "This hook should return the DECL of a function that implements reciprocal of\n\
2170the builtin function with builtin function code @var{fn}, or\n\
2171@code{NULL_TREE} if such a function is not available.  @var{md_fn} is true\n\
2172when @var{fn} is a code of a machine-dependent builtin function.  When\n\
2173@var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2174of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2175function are valid.",
2176 tree, (unsigned fn, bool md_fn, bool sqrt),
2177 default_builtin_reciprocal)
2178
2179/* For a vendor-specific TYPE, return a pointer to a statically-allocated
2180   string containing the C++ mangling for TYPE.  In all other cases, return
2181   NULL.  */
2182DEFHOOK
2183(mangle_type,
2184 "If your target defines any fundamental types, or any types your target\n\
2185uses should be mangled differently from the default, define this hook\n\
2186to return the appropriate encoding for these types as part of a C++\n\
2187mangled name.  The @var{type} argument is the tree structure representing\n\
2188the type to be mangled.  The hook may be applied to trees which are\n\
2189not target-specific fundamental types; it should return @code{NULL}\n\
2190for all such types, as well as arguments it does not recognize.  If the\n\
2191return value is not @code{NULL}, it must point to a statically-allocated\n\
2192string constant.\n\
2193\n\
2194Target-specific fundamental types might be new fundamental types or\n\
2195qualified versions of ordinary fundamental types.  Encode new\n\
2196fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2197is the name used for the type in source code, and @var{n} is the\n\
2198length of @var{name} in decimal.  Encode qualified versions of\n\
2199ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2200@var{name} is the name used for the type qualifier in source code,\n\
2201@var{n} is the length of @var{name} as above, and @var{code} is the\n\
2202code used to represent the unqualified version of this type.  (See\n\
2203@code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2204codes.)  In both cases the spaces are for clarity; do not include any\n\
2205spaces in your string.\n\
2206\n\
2207This hook is applied to types prior to typedef resolution.  If the mangled\n\
2208name for a particular type depends only on that type's main variant, you\n\
2209can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2210before mangling.\n\
2211\n\
2212The default version of this hook always returns @code{NULL}, which is\n\
2213appropriate for a target that does not define any new fundamental\n\
2214types.",
2215 const char *, (const_tree type),
2216 hook_constcharptr_const_tree_null)
2217
2218/* Make any adjustments to libfunc names needed for this target.  */
2219DEFHOOK
2220(init_libfuncs,
2221 "This hook should declare additional library routines or rename\n\
2222existing ones, using the functions @code{set_optab_libfunc} and\n\
2223@code{init_one_libfunc} defined in @file{optabs.c}.\n\
2224@code{init_optabs} calls this macro after initializing all the normal\n\
2225library routines.\n\
2226\n\
2227The default is to do nothing.  Most ports don't need to define this hook.",
2228 void, (void),
2229 hook_void_void)
2230
2231 /* Add a __gnu_ prefix to library functions rather than just __.  */
2232DEFHOOKPOD
2233(libfunc_gnu_prefix,
2234 "If false (the default), internal library routines start with two\n\
2235underscores.  If set to true, these routines start with @code{__gnu_}\n\
2236instead.  E.g., @code{__muldi3} changes to @code{__gnu_muldi3}.  This\n\
2237currently only affects functions defined in @file{libgcc2.c}.  If this\n\
2238is set to true, the @file{tm.h} file must also\n\
2239@code{#define LIBGCC2_GNU_PREFIX}.",
2240  bool, false)
2241
2242/* Given a decl, a section name, and whether the decl initializer
2243   has relocs, choose attributes for the section.  */
2244/* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION.  */
2245DEFHOOK
2246(section_type_flags,
2247 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2248based on a variable or function decl, a section name, and whether or not the\n\
2249declaration's initializer may contain runtime relocations.  @var{decl} may be\n\
2250null, in which case read-write data should be assumed.\n\
2251\n\
2252The default version of this function handles choosing code vs data,\n\
2253read-only vs read-write data, and @code{flag_pic}.  You should only\n\
2254need to override this if your target has special flags that might be\n\
2255set via @code{__attribute__}.",
2256 unsigned int, (tree decl, const char *name, int reloc),
2257 default_section_type_flags)
2258
2259DEFHOOK
2260(libc_has_function,
2261 "This hook determines whether a function from a class of functions\n\
2262@var{fn_class} is present at the runtime.",
2263 bool, (enum function_class fn_class),
2264 default_libc_has_function)
2265
2266/* True if new jumps cannot be created, to replace existing ones or
2267   not, at the current point in the compilation.  */
2268DEFHOOK
2269(cannot_modify_jumps_p,
2270 "This target hook returns @code{true} past the point in which new jump\n\
2271instructions could be created.  On machines that require a register for\n\
2272every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2273reload, so this target hook should be defined to a function such as:\n\
2274\n\
2275@smallexample\n\
2276static bool\n\
2277cannot_modify_jumps_past_reload_p ()\n\
2278@{\n\
2279  return (reload_completed || reload_in_progress);\n\
2280@}\n\
2281@end smallexample",
2282 bool, (void),
2283 hook_bool_void_false)
2284
2285/* True if FOLLOWER may be modified to follow FOLLOWEE.  */
2286DEFHOOK
2287(can_follow_jump,
2288 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2289  return true if FOLLOWER may be modified to follow FOLLOWEE;\
2290  false, if it can't.\
2291  For example, on some targets, certain kinds of branches can't be made to\
2292  follow through a hot/cold partitioning.",
2293 bool, (const_rtx follower, const_rtx followee),
2294 hook_bool_const_rtx_const_rtx_true)
2295
2296/* Return a register class for which branch target register
2297   optimizations should be applied.  */
2298DEFHOOK
2299(branch_target_register_class,
2300 "This target hook returns a register class for which branch target register\n\
2301optimizations should be applied.  All registers in this class should be\n\
2302usable interchangeably.  After reload, registers in this class will be\n\
2303re-allocated and loads will be hoisted out of loops and be subjected\n\
2304to inter-block scheduling.",
2305 reg_class_t, (void),
2306 default_branch_target_register_class)
2307
2308/* Return true if branch target register optimizations should include
2309   callee-saved registers that are not already live during the current
2310   function.  AFTER_PE_GEN is true if prologues and epilogues have
2311   already been generated.  */
2312DEFHOOK
2313(branch_target_register_callee_saved,
2314 "Branch target register optimization will by default exclude callee-saved\n\
2315registers\n\
2316that are not already live during the current function; if this target hook\n\
2317returns true, they will be included.  The target code must than make sure\n\
2318that all target registers in the class returned by\n\
2319@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2320saved.  @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2321epilogues have already been generated.  Note, even if you only return\n\
2322true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2323to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2324to reserve space for caller-saved target registers.",
2325 bool, (bool after_prologue_epilogue_gen),
2326 hook_bool_bool_false)
2327
2328/* Return true if the target supports conditional execution.  */
2329DEFHOOK
2330(have_conditional_execution,
2331 "This target hook returns true if the target supports conditional execution.\n\
2332This target hook is required only when the target has several different\n\
2333modes and they have different conditional execution capability, such as ARM.",
2334 bool, (void),
2335 default_have_conditional_execution)
2336
2337/* Return a new value for loop unroll size.  */
2338DEFHOOK
2339(loop_unroll_adjust,
2340 "This target hook returns a new value for the number of times @var{loop}\n\
2341should be unrolled. The parameter @var{nunroll} is the number of times\n\
2342the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2343the loop, which is going to be checked for unrolling. This target hook\n\
2344is required only when the target has special constraints like maximum\n\
2345number of memory accesses.",
2346 unsigned, (unsigned nunroll, struct loop *loop),
2347 NULL)
2348
2349/* True if X is a legitimate MODE-mode immediate operand.  */
2350DEFHOOK
2351(legitimate_constant_p,
2352 "This hook returns true if @var{x} is a legitimate constant for a\n\
2353@var{mode}-mode immediate operand on the target machine.  You can assume that\n\
2354@var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2355\n\
2356The default definition returns true.",
2357 bool, (enum machine_mode mode, rtx x),
2358 hook_bool_mode_rtx_true)
2359
2360/* True if the constant X cannot be placed in the constant pool.  */
2361DEFHOOK
2362(cannot_force_const_mem,
2363 "This hook should return true if @var{x} is of a form that cannot (or\n\
2364should not) be spilled to the constant pool.  @var{mode} is the mode\n\
2365of @var{x}.\n\
2366\n\
2367The default version of this hook returns false.\n\
2368\n\
2369The primary reason to define this hook is to prevent reload from\n\
2370deciding that a non-legitimate constant would be better reloaded\n\
2371from the constant pool instead of spilling and reloading a register\n\
2372holding the constant.  This restriction is often true of addresses\n\
2373of TLS symbols for various targets.",
2374 bool, (enum machine_mode mode, rtx x),
2375 hook_bool_mode_rtx_false)
2376
2377DEFHOOK_UNDOC
2378(cannot_copy_insn_p,
2379 "True if the insn @var{x} cannot be duplicated.",
2380 bool, (rtx), NULL)
2381
2382/* True if X is considered to be commutative.  */
2383DEFHOOK
2384(commutative_p,
2385 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2386Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2387PLUS to be commutative inside a MEM@.  @var{outer_code} is the rtx code\n\
2388of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2389 bool, (const_rtx x, int outer_code),
2390 hook_bool_const_rtx_commutative_p)
2391
2392/* True if ADDR is an address-expression whose effect depends
2393   on the mode of the memory reference it is used in.  */
2394DEFHOOK
2395(mode_dependent_address_p,
2396 "This hook returns @code{true} if memory address @var{addr} in address\n\
2397space @var{addrspace} can have\n\
2398different meanings depending on the machine mode of the memory\n\
2399reference it is used for or if the address is valid for some modes\n\
2400but not others.\n\
2401\n\
2402Autoincrement and autodecrement addresses typically have mode-dependent\n\
2403effects because the amount of the increment or decrement is the size\n\
2404of the operand being addressed.  Some machines have other mode-dependent\n\
2405addresses.  Many RISC machines have no mode-dependent addresses.\n\
2406\n\
2407You may assume that @var{addr} is a valid address for the machine.\n\
2408\n\
2409The default version of this hook returns @code{false}.",
2410 bool, (const_rtx addr, addr_space_t addrspace),
2411 default_mode_dependent_address_p)
2412
2413/* Given an invalid address X for a given machine mode, try machine-specific
2414   ways to make it legitimate.  Return X or an invalid address on failure.  */
2415DEFHOOK
2416(legitimize_address,
2417 "This hook is given an invalid memory address @var{x} for an\n\
2418operand of mode @var{mode} and should try to return a valid memory\n\
2419address.\n\
2420\n\
2421@findex break_out_memory_refs\n\
2422@var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2423and @var{oldx} will be the operand that was given to that function to produce\n\
2424@var{x}.\n\
2425\n\
2426The code of the hook should not alter the substructure of\n\
2427@var{x}.  If it transforms @var{x} into a more legitimate form, it\n\
2428should return the new @var{x}.\n\
2429\n\
2430It is not necessary for this hook to come up with a legitimate address,\n\
2431with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2432The compiler has standard ways of doing so in all cases.  In fact, if\n\
2433the target supports only emulated TLS, it\n\
2434is safe to omit this hook or make it return @var{x} if it cannot find\n\
2435a valid way to legitimize the address.  But often a machine-dependent\n\
2436strategy can generate better code.",
2437 rtx, (rtx x, rtx oldx, enum machine_mode mode),
2438 default_legitimize_address)
2439
2440/* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS.  */
2441DEFHOOK
2442(delegitimize_address,
2443 "This hook is used to undo the possibly obfuscating effects of the\n\
2444@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2445macros.  Some backend implementations of these macros wrap symbol\n\
2446references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2447addressing modes.  This target hook allows GCC's optimizers to understand\n\
2448the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2449into their original form.",
2450 rtx, (rtx x),
2451 delegitimize_mem_from_attrs)
2452
2453/* Given an RTX, return true if it is not ok to emit it into debug info
2454   section.  */
2455DEFHOOK
2456(const_not_ok_for_debug_p,
2457 "This hook should return true if @var{x} should not be emitted into\n\
2458debug sections.",
2459 bool, (rtx x),
2460 hook_bool_rtx_false)
2461
2462/* Given an address RTX, say whether it is valid.  */
2463DEFHOOK
2464(legitimate_address_p,
2465 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2466address on the target machine for a memory operand of mode @var{mode}.\n\
2467\n\
2468Legitimate addresses are defined in two variants: a strict variant and a\n\
2469non-strict one.  The @var{strict} parameter chooses which variant is\n\
2470desired by the caller.\n\
2471\n\
2472The strict variant is used in the reload pass.  It must be defined so\n\
2473that any pseudo-register that has not been allocated a hard register is\n\
2474considered a memory reference.  This is because in contexts where some\n\
2475kind of register is required, a pseudo-register with no hard register\n\
2476must be rejected.  For non-hard registers, the strict variant should look\n\
2477up the @code{reg_renumber} array; it should then proceed using the hard\n\
2478register number in the array, or treat the pseudo as a memory reference\n\
2479if the array holds @code{-1}.\n\
2480\n\
2481The non-strict variant is used in other passes.  It must be defined to\n\
2482accept all pseudo-registers in every context where some kind of\n\
2483register is required.\n\
2484\n\
2485Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2486and an integer are stored inside a @code{const} RTX to mark them as\n\
2487constant.  Therefore, there is no need to recognize such sums\n\
2488specifically as legitimate addresses.  Normally you would simply\n\
2489recognize any @code{const} as legitimate.\n\
2490\n\
2491Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2492sums that are not marked with  @code{const}.  It assumes that a naked\n\
2493@code{plus} indicates indexing.  If so, then you @emph{must} reject such\n\
2494naked constant sums as illegitimate addresses, so that none of them will\n\
2495be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2496\n\
2497@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2498On some machines, whether a symbolic address is legitimate depends on\n\
2499the section that the address refers to.  On these machines, define the\n\
2500target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2501into the @code{symbol_ref}, and then check for it here.  When you see a\n\
2502@code{const}, you will have to look inside it to find the\n\
2503@code{symbol_ref} in order to determine the section.  @xref{Assembler\n\
2504Format}.\n\
2505\n\
2506@cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2507Some ports are still using a deprecated legacy substitute for\n\
2508this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro.  This macro\n\
2509has this syntax:\n\
2510\n\
2511@example\n\
2512#define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2513@end example\n\
2514\n\
2515@noindent\n\
2516and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2517address on the target machine for a memory operand of mode @var{mode}.\n\
2518\n\
2519@findex REG_OK_STRICT\n\
2520Compiler source files that want to use the strict variant of this\n\
2521macro define the macro @code{REG_OK_STRICT}.  You should use an\n\
2522@code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2523that case and the non-strict variant otherwise.\n\
2524\n\
2525Using the hook is usually simpler because it limits the number of\n\
2526files that are recompiled when changes are made.",
2527 bool, (enum machine_mode mode, rtx x, bool strict),
2528 default_legitimate_address_p)
2529
2530/* True if the given constant can be put into an object_block.  */
2531DEFHOOK
2532(use_blocks_for_constant_p,
2533 "This hook should return true if pool entries for constant @var{x} can\n\
2534be placed in an @code{object_block} structure.  @var{mode} is the mode\n\
2535of @var{x}.\n\
2536\n\
2537The default version returns false for all constants.",
2538 bool, (enum machine_mode mode, const_rtx x),
2539 hook_bool_mode_const_rtx_false)
2540
2541/* True if the given decl can be put into an object_block.  */
2542DEFHOOK
2543(use_blocks_for_decl_p,
2544 "This hook should return true if pool entries for @var{decl} should\n\
2545be placed in an @code{object_block} structure.\n\
2546\n\
2547The default version returns true for all decls.",
2548 bool, (const_tree decl),
2549 hook_bool_const_tree_true)
2550
2551/* The minimum and maximum byte offsets for anchored addresses.  */
2552DEFHOOKPOD
2553(min_anchor_offset,
2554 "The minimum offset that should be applied to a section anchor.\n\
2555On most targets, it should be the smallest offset that can be\n\
2556applied to a base register while still giving a legitimate address\n\
2557for every mode.  The default value is 0.",
2558 HOST_WIDE_INT, 0)
2559
2560DEFHOOKPOD
2561(max_anchor_offset,
2562 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2563offset that should be applied to section anchors.  The default\n\
2564value is 0.",
2565 HOST_WIDE_INT, 0)
2566
2567/* True if section anchors can be used to access the given symbol.  */
2568DEFHOOK
2569(use_anchors_for_symbol_p,
2570 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2571@var{x}.  You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2572@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2573\n\
2574The default version is correct for most targets, but you might need to\n\
2575intercept this hook to handle things like target-specific attributes\n\
2576or target-specific sections.",
2577 bool, (const_rtx x),
2578 default_use_anchors_for_symbol_p)
2579
2580/* True if target supports indirect functions.  */
2581DEFHOOK
2582(has_ifunc_p,
2583 "It returns true if the target supports GNU indirect functions.\n\
2584The support includes the assembler, linker and dynamic linker.\n\
2585The default value of this hook is based on target's libc.",
2586 bool, (void),
2587 default_has_ifunc_p)
2588
2589/* True if it is OK to do sibling call optimization for the specified
2590   call expression EXP.  DECL will be the called function, or NULL if
2591   this is an indirect call.  */
2592DEFHOOK
2593(function_ok_for_sibcall,
2594 "True if it is OK to do sibling call optimization for the specified\n\
2595call expression @var{exp}.  @var{decl} will be the called function,\n\
2596or @code{NULL} if this is an indirect call.\n\
2597\n\
2598It is not uncommon for limitations of calling conventions to prevent\n\
2599tail calls to functions outside the current unit of translation, or\n\
2600during PIC compilation.  The hook is used to enforce these restrictions,\n\
2601as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2602``normal'' call.  The criteria for successful sibling call optimization\n\
2603may vary greatly between different architectures.",
2604 bool, (tree decl, tree exp),
2605 hook_bool_tree_tree_false)
2606
2607/* Establish appropriate back-end context for processing the function
2608   FNDECL.  The argument might be NULL to indicate processing at top
2609   level, outside of any function scope.  */
2610DEFHOOK
2611(set_current_function,
2612 "The compiler invokes this hook whenever it changes its current function\n\
2613context (@code{cfun}).  You can define this function if\n\
2614the back end needs to perform any initialization or reset actions on a\n\
2615per-function basis.  For example, it may be used to implement function\n\
2616attributes that affect register usage or code generation patterns.\n\
2617The argument @var{decl} is the declaration for the new function context,\n\
2618and may be null to indicate that the compiler has left a function context\n\
2619and is returning to processing at the top level.\n\
2620The default hook function does nothing.\n\
2621\n\
2622GCC sets @code{cfun} to a dummy function context during initialization of\n\
2623some parts of the back end.  The hook function is not invoked in this\n\
2624situation; you need not worry about the hook being invoked recursively,\n\
2625or when the back end is in a partially-initialized state.\n\
2626@code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2627outside of any function scope.",
2628 void, (tree decl), hook_void_tree)
2629
2630/* True if EXP should be placed in a "small data" section.  */
2631DEFHOOK
2632(in_small_data_p,
2633 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2634The default version of this hook always returns false.",
2635 bool, (const_tree exp),
2636 hook_bool_const_tree_false)
2637
2638/* True if EXP names an object for which name resolution must resolve
2639   to the current executable or shared library.  */
2640DEFHOOK
2641(binds_local_p,
2642 "Returns true if @var{exp} names an object for which name resolution\n\
2643rules must resolve to the current ``module'' (dynamic shared library\n\
2644or executable image).\n\
2645\n\
2646The default version of this hook implements the name resolution rules\n\
2647for ELF, which has a looser model of global name binding than other\n\
2648currently supported object file formats.",
2649 bool, (const_tree exp),
2650 default_binds_local_p)
2651
2652/* Check if profiling code is before or after prologue.  */
2653DEFHOOK
2654(profile_before_prologue,
2655 "It returns true if target wants profile code emitted before prologue.\n\n\
2656The default version of this hook use the target macro\n\
2657@code{PROFILE_BEFORE_PROLOGUE}.",
2658 bool, (void),
2659 default_profile_before_prologue)
2660
2661/* Modify and return the identifier of a DECL's external name,
2662   originally identified by ID, as required by the target,
2663   (eg, append @nn to windows32 stdcall function names).
2664   The default is to return ID without modification. */
2665DEFHOOK
2666(mangle_decl_assembler_name,
2667 "Define this hook if you need to postprocess the assembler name generated\n\
2668by target-independent code.  The @var{id} provided to this hook will be\n\
2669the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2670or the mangled name of the @var{decl} in C++).  The return value of the\n\
2671hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2672your target system.  The default implementation of this hook just\n\
2673returns the @var{id} provided.",
2674 tree, (tree decl, tree  id),
2675 default_mangle_decl_assembler_name)
2676
2677/* Do something target-specific to record properties of the DECL into
2678   the associated SYMBOL_REF.  */
2679DEFHOOK
2680(encode_section_info,
2681 "Define this hook if references to a symbol or a constant must be\n\
2682treated differently depending on something about the variable or\n\
2683function named by the symbol (such as what section it is in).\n\
2684\n\
2685The hook is executed immediately after rtl has been created for\n\
2686@var{decl}, which may be a variable or function declaration or\n\
2687an entry in the constant pool.  In either case, @var{rtl} is the\n\
2688rtl in question.  Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
2689in this hook; that field may not have been initialized yet.\n\
2690\n\
2691In the case of a constant, it is safe to assume that the rtl is\n\
2692a @code{mem} whose address is a @code{symbol_ref}.  Most decls\n\
2693will also have this form, but that is not guaranteed.  Global\n\
2694register variables, for instance, will have a @code{reg} for their\n\
2695rtl.  (Normally the right thing to do with such unusual rtl is\n\
2696leave it alone.)\n\
2697\n\
2698The @var{new_decl_p} argument will be true if this is the first time\n\
2699that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl.  It will\n\
2700be false for subsequent invocations, which will happen for duplicate\n\
2701declarations.  Whether or not anything must be done for the duplicate\n\
2702declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
2703@var{new_decl_p} is always true when the hook is called for a constant.\n\
2704\n\
2705@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
2706The usual thing for this hook to do is to record flags in the\n\
2707@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
2708Historically, the name string was modified if it was necessary to\n\
2709encode more than one bit of information, but this practice is now\n\
2710discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
2711\n\
2712The default definition of this hook, @code{default_encode_section_info}\n\
2713in @file{varasm.c}, sets a number of commonly-useful bits in\n\
2714@code{SYMBOL_REF_FLAGS}.  Check whether the default does what you need\n\
2715before overriding it.",
2716 void, (tree decl, rtx rtl, int new_decl_p),
2717 default_encode_section_info)
2718
2719/* Undo the effects of encode_section_info on the symbol string.  */
2720DEFHOOK
2721(strip_name_encoding,
2722 "Decode @var{name} and return the real name part, sans\n\
2723the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
2724may have added.",
2725 const char *, (const char *name),
2726 default_strip_name_encoding)
2727
2728/* If shift optabs for MODE are known to always truncate the shift count,
2729   return the mask that they apply.  Return 0 otherwise.  */
2730DEFHOOK
2731(shift_truncation_mask,
2732 "This function describes how the standard shift patterns for @var{mode}\n\
2733deal with shifts by negative amounts or by more than the width of the mode.\n\
2734@xref{shift patterns}.\n\
2735\n\
2736On many machines, the shift patterns will apply a mask @var{m} to the\n\
2737shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
2738equivalent to an arbitrary-width shift of @var{x} by @var{y & m}.  If\n\
2739this is true for mode @var{mode}, the function should return @var{m},\n\
2740otherwise it should return 0.  A return value of 0 indicates that no\n\
2741particular behavior is guaranteed.\n\
2742\n\
2743Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
2744@emph{not} apply to general shift rtxes; it applies only to instructions\n\
2745that are generated by the named shift patterns.\n\
2746\n\
2747The default implementation of this function returns\n\
2748@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
2749and 0 otherwise.  This definition is always safe, but if\n\
2750@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
2751nevertheless truncate the shift count, you may get better code\n\
2752by overriding it.",
2753 unsigned HOST_WIDE_INT, (enum machine_mode mode),
2754 default_shift_truncation_mask)
2755
2756/* Return the number of divisions in the given MODE that should be present,
2757   so that it is profitable to turn the division into a multiplication by
2758   the reciprocal.  */
2759DEFHOOK
2760(min_divisions_for_recip_mul,
2761 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
2762divisions by the same divisor, by turning them into multiplications by\n\
2763the reciprocal.  This target hook specifies the minimum number of divisions\n\
2764that should be there for GCC to perform the optimization for a variable\n\
2765of mode @var{mode}.  The default implementation returns 3 if the machine\n\
2766has an instruction for the division, and 2 if it does not.",
2767 unsigned int, (enum machine_mode mode),
2768 default_min_divisions_for_recip_mul)
2769
2770/* If the representation of integral MODE is such that values are
2771   always sign-extended to a wider mode MODE_REP then return
2772   SIGN_EXTEND.  Return UNKNOWN otherwise.  */
2773/* Note that the return type ought to be RTX_CODE, but that's not
2774   necessarily defined at this point.  */
2775DEFHOOK
2776(mode_rep_extended,
2777 "The representation of an integral mode can be such that the values\n\
2778are always extended to a wider integral mode.  Return\n\
2779@code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
2780sign-extended form to @var{rep_mode}.  Return @code{UNKNOWN}\n\
2781otherwise.  (Currently, none of the targets use zero-extended\n\
2782representation this way so unlike @code{LOAD_EXTEND_OP},\n\
2783@code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
2784@code{SIGN_EXTEND} or @code{UNKNOWN}.  Also no target extends\n\
2785@var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
2786widest integral mode and currently we take advantage of this fact.)\n\
2787\n\
2788Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
2789value even if the extension is not performed on certain hard registers\n\
2790as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
2791@code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
2792\n\
2793Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
2794describe two related properties.  If you define\n\
2795@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
2796to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
2797extension.\n\
2798\n\
2799In order to enforce the representation of @code{mode},\n\
2800@code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
2801@code{mode}.",
2802 int, (enum machine_mode mode, enum machine_mode rep_mode),
2803 default_mode_rep_extended)
2804
2805/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))).  */
2806DEFHOOK
2807(valid_pointer_mode,
2808 "Define this to return nonzero if the port can handle pointers\n\
2809with machine mode @var{mode}.  The default version of this\n\
2810hook returns true for both @code{ptr_mode} and @code{Pmode}.",
2811 bool, (enum machine_mode mode),
2812 default_valid_pointer_mode)
2813
2814/* Disambiguate with errno.  */
2815DEFHOOK
2816(ref_may_alias_errno,
2817 "Define this to return nonzero if the memory reference @var{ref}\
2818  may alias with the system C library errno location.  The default\
2819  version of this hook assumes the system C library errno location\
2820  is either a declaration of type int or accessed by dereferencing\
2821  a pointer to int.",
2822 bool, (struct ao_ref *ref),
2823 default_ref_may_alias_errno)
2824
2825/* Support for named address spaces.  */
2826#undef HOOK_PREFIX
2827#define HOOK_PREFIX "TARGET_ADDR_SPACE_"
2828HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
2829
2830/* MODE to use for a pointer into another address space.  */
2831DEFHOOK
2832(pointer_mode,
2833 "Define this to return the machine mode to use for pointers to\n\
2834@var{address_space} if the target supports named address spaces.\n\
2835The default version of this hook returns @code{ptr_mode} for the\n\
2836generic address space only.",
2837 enum machine_mode, (addr_space_t address_space),
2838 default_addr_space_pointer_mode)
2839
2840/* MODE to use for an address in another address space.  */
2841DEFHOOK
2842(address_mode,
2843 "Define this to return the machine mode to use for addresses in\n\
2844@var{address_space} if the target supports named address spaces.\n\
2845The default version of this hook returns @code{Pmode} for the\n\
2846generic address space only.",
2847 enum machine_mode, (addr_space_t address_space),
2848 default_addr_space_address_mode)
2849
2850/* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
2851   in another address space.  */
2852DEFHOOK
2853(valid_pointer_mode,
2854 "Define this to return nonzero if the port can handle pointers\n\
2855with machine mode @var{mode} to address space @var{as}.  This target\n\
2856hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
2857except that it includes explicit named address space support.  The default\n\
2858version of this hook returns true for the modes returned by either the\n\
2859@code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
2860target hooks for the given address space.",
2861 bool, (enum machine_mode mode, addr_space_t as),
2862 default_addr_space_valid_pointer_mode)
2863
2864/* True if an address is a valid memory address to a given named address
2865   space for a given mode.  */
2866DEFHOOK
2867(legitimate_address_p,
2868 "Define this to return true if @var{exp} is a valid address for mode\n\
2869@var{mode} in the named address space @var{as}.  The @var{strict}\n\
2870parameter says whether strict addressing is in effect after reload has\n\
2871finished.  This target hook is the same as the\n\
2872@code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
2873explicit named address space support.",
2874 bool, (enum machine_mode mode, rtx exp, bool strict, addr_space_t as),
2875 default_addr_space_legitimate_address_p)
2876
2877/* Return an updated address to convert an invalid pointer to a named
2878   address space to a valid one.  If NULL_RTX is returned use machine
2879   independent methods to make the address valid.  */
2880DEFHOOK
2881(legitimize_address,
2882 "Define this to modify an invalid address @var{x} to be a valid address\n\
2883with mode @var{mode} in the named address space @var{as}.  This target\n\
2884hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
2885except that it includes explicit named address space support.",
2886 rtx, (rtx x, rtx oldx, enum machine_mode mode, addr_space_t as),
2887 default_addr_space_legitimize_address)
2888
2889/* True if one named address space is a subset of another named address. */
2890DEFHOOK
2891(subset_p,
2892 "Define this to return whether the @var{subset} named address space is\n\
2893contained within the @var{superset} named address space.  Pointers to\n\
2894a named address space that is a subset of another named address space\n\
2895will be converted automatically without a cast if used together in\n\
2896arithmetic operations.  Pointers to a superset address space can be\n\
2897converted to pointers to a subset address space via explicit casts.",
2898 bool, (addr_space_t subset, addr_space_t superset),
2899 default_addr_space_subset_p)
2900
2901/* Function to convert an rtl expression from one address space to another.  */
2902DEFHOOK
2903(convert,
2904 "Define this to convert the pointer expression represented by the RTL\n\
2905@var{op} with type @var{from_type} that points to a named address\n\
2906space to a new pointer expression with type @var{to_type} that points\n\
2907to a different named address space.  When this hook it called, it is\n\
2908guaranteed that one of the two address spaces is a subset of the other,\n\
2909as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
2910 rtx, (rtx op, tree from_type, tree to_type),
2911 default_addr_space_convert)
2912
2913HOOK_VECTOR_END (addr_space)
2914
2915#undef HOOK_PREFIX
2916#define HOOK_PREFIX "TARGET_"
2917
2918/* True if MODE is valid for the target.  By "valid", we mean able to
2919   be manipulated in non-trivial ways.  In particular, this means all
2920   the arithmetic is supported.  */
2921DEFHOOK
2922(scalar_mode_supported_p,
2923 "Define this to return nonzero if the port is prepared to handle\n\
2924insns involving scalar mode @var{mode}.  For a scalar mode to be\n\
2925considered supported, all the basic arithmetic and comparisons\n\
2926must work.\n\
2927\n\
2928The default version of this hook returns true for any mode\n\
2929required to handle the basic C types (as defined by the port).\n\
2930Included here are the double-word arithmetic supported by the\n\
2931code in @file{optabs.c}.",
2932 bool, (enum machine_mode mode),
2933 default_scalar_mode_supported_p)
2934
2935/* Similarly for vector modes.  "Supported" here is less strict.  At
2936   least some operations are supported; need to check optabs or builtins
2937   for further details.  */
2938DEFHOOK
2939(vector_mode_supported_p,
2940 "Define this to return nonzero if the port is prepared to handle\n\
2941insns involving vector mode @var{mode}.  At the very least, it\n\
2942must have move patterns for this mode.",
2943 bool, (enum machine_mode mode),
2944 hook_bool_mode_false)
2945
2946DEFHOOK
2947(vector_alignment,
2948 "This hook can be used to define the alignment for a vector of type\n\
2949@var{type}, in order to comply with a platform ABI.  The default is to\n\
2950require natural alignment for vector types.  The alignment returned by\n\
2951this hook must be a power-of-two multiple of the default alignment of\n\
2952the vector element type.",
2953 HOST_WIDE_INT, (const_tree type),
2954 default_vector_alignment)
2955
2956/* True if we should try to use a scalar mode to represent an array,
2957   overriding the usual MAX_FIXED_MODE limit.  */
2958DEFHOOK
2959(array_mode_supported_p,
2960 "Return true if GCC should try to use a scalar mode to store an array\n\
2961of @var{nelems} elements, given that each element has mode @var{mode}.\n\
2962Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
2963and allows GCC to use any defined integer mode.\n\
2964\n\
2965One use of this hook is to support vector load and store operations\n\
2966that operate on several homogeneous vectors.  For example, ARM NEON\n\
2967has operations like:\n\
2968\n\
2969@smallexample\n\
2970int8x8x3_t vld3_s8 (const int8_t *)\n\
2971@end smallexample\n\
2972\n\
2973where the return type is defined as:\n\
2974\n\
2975@smallexample\n\
2976typedef struct int8x8x3_t\n\
2977@{\n\
2978  int8x8_t val[3];\n\
2979@} int8x8x3_t;\n\
2980@end smallexample\n\
2981\n\
2982If this hook allows @code{val} to have a scalar mode, then\n\
2983@code{int8x8x3_t} can have the same mode.  GCC can then store\n\
2984@code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
2985 bool, (enum machine_mode mode, unsigned HOST_WIDE_INT nelems),
2986 hook_bool_mode_uhwi_false)
2987
2988/* Compute cost of moving data from a register of class FROM to one of
2989   TO, using MODE.  */
2990DEFHOOK
2991(register_move_cost,
2992 "This target hook should return the cost of moving data of mode @var{mode}\n\
2993from a register in class @var{from} to one in class @var{to}.  The classes\n\
2994are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
2995A value of 2 is the default; other values are interpreted relative to\n\
2996that.\n\
2997\n\
2998It is not required that the cost always equal 2 when @var{from} is the\n\
2999same as @var{to}; on some machines it is expensive to move between\n\
3000registers if they are not general registers.\n\
3001\n\
3002If reload sees an insn consisting of a single @code{set} between two\n\
3003hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3004classes returns a value of 2, reload does not check to ensure that the\n\
3005constraints of the insn are met.  Setting a cost of other than 2 will\n\
3006allow reload to verify that the constraints are met.  You should do this\n\
3007if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3008\n\
3009The default version of this function returns 2.",
3010 int, (enum machine_mode mode, reg_class_t from, reg_class_t to),
3011 default_register_move_cost)
3012
3013/* Compute cost of moving registers to/from memory.  */
3014/* ??? Documenting the argument types for this hook requires a GFDL
3015   license grant.  Also, the documentation uses a different name for RCLASS.  */
3016DEFHOOK
3017(memory_move_cost,
3018 "This target hook should return the cost of moving data of mode @var{mode}\n\
3019between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3020if the value is to be written to memory, @code{true} if it is to be read in.\n\
3021This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3022If moving between registers and memory is more expensive than between two\n\
3023registers, you should add this target hook to express the relative cost.\n\
3024\n\
3025If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3026the cost of copying via a secondary reload register, if one is\n\
3027needed.  If your machine requires a secondary reload register to copy\n\
3028between memory and a register of @var{rclass} but the reload mechanism is\n\
3029more complex than copying via an intermediate, use this target hook to\n\
3030reflect the actual cost of the move.\n\
3031\n\
3032GCC defines the function @code{memory_move_secondary_cost} if\n\
3033secondary reloads are needed.  It computes the costs due to copying via\n\
3034a secondary register.  If your machine copies from memory using a\n\
3035secondary register in the conventional way but the default base value of\n\
30364 is not correct for your machine, use this target hook to add some other\n\
3037value to the result of that function.  The arguments to that function\n\
3038are the same as to this target hook.",
3039 int, (enum machine_mode mode, reg_class_t rclass, bool in),
3040 default_memory_move_cost)
3041
3042/* True for MODE if the target expects that registers in this mode will
3043   be allocated to registers in a small register class.  The compiler is
3044   allowed to use registers explicitly used in the rtl as spill registers
3045   but it should prevent extending the lifetime of these registers.  */
3046DEFHOOK
3047(small_register_classes_for_mode_p,
3048 "Define this to return nonzero for machine modes for which the port has\n\
3049small register classes.  If this target hook returns nonzero for a given\n\
3050@var{mode}, the compiler will try to minimize the lifetime of registers\n\
3051in @var{mode}.  The hook may be called with @code{VOIDmode} as argument.\n\
3052In this case, the hook is expected to return nonzero if it returns nonzero\n\
3053for any mode.\n\
3054\n\
3055On some machines, it is risky to let hard registers live across arbitrary\n\
3056insns.  Typically, these machines have instructions that require values\n\
3057to be in specific registers (like an accumulator), and reload will fail\n\
3058if the required hard register is used for another purpose across such an\n\
3059insn.\n\
3060\n\
3061Passes before reload do not know which hard registers will be used\n\
3062in an instruction, but the machine modes of the registers set or used in\n\
3063the instruction are already known.  And for some machines, register\n\
3064classes are small for, say, integer registers but not for floating point\n\
3065registers.  For example, the AMD x86-64 architecture requires specific\n\
3066registers for the legacy x86 integer instructions, but there are many\n\
3067SSE registers for floating point operations.  On such targets, a good\n\
3068strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3069machine modes but zero for the SSE register classes.\n\
3070\n\
3071The default version of this hook returns false for any mode.  It is always\n\
3072safe to redefine this hook to return with a nonzero value.  But if you\n\
3073unnecessarily define it, you will reduce the amount of optimizations\n\
3074that can be performed in some cases.  If you do not define this hook\n\
3075to return a nonzero value when it is required, the compiler will run out\n\
3076of spill registers and print a fatal error message.",
3077 bool, (enum machine_mode mode),
3078 hook_bool_mode_false)
3079
3080/* Register number for a flags register.  Only needs to be defined if the
3081   target is constrainted to use post-reload comparison elimination.  */
3082DEFHOOKPOD
3083(flags_regnum,
3084 "If the target has a dedicated flags register, and it needs to use the\
3085 post-reload comparison elimination pass, then this value should be set\
3086 appropriately.",
3087 unsigned int, INVALID_REGNUM)
3088
3089/* Compute a (partial) cost for rtx X.  Return true if the complete
3090   cost has been computed, and false if subexpressions should be
3091   scanned.  In either case, *TOTAL contains the cost result.  */
3092/* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
3093   not necessarily defined at this point.  */
3094DEFHOOK
3095(rtx_costs,
3096 "This target hook describes the relative costs of RTL expressions.\n\
3097\n\
3098The cost may depend on the precise form of the expression, which is\n\
3099available for examination in @var{x}, and the fact that @var{x} appears\n\
3100as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3101That is, the hook can assume that there is some rtx @var{y} such\n\
3102that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3103either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3104(b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3105\n\
3106@var{code} is @var{x}'s expression code---redundant, since it can be\n\
3107obtained with @code{GET_CODE (@var{x})}.\n\
3108\n\
3109In implementing this hook, you can use the construct\n\
3110@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3111instructions.\n\
3112\n\
3113On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3114for the cost of the expression.  The hook should modify this value as\n\
3115necessary.  Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3116for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3117operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3118\n\
3119When optimizing for code size, i.e.@: when @code{speed} is\n\
3120false, this target hook should be used to estimate the relative\n\
3121size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3122\n\
3123The hook returns true when all subexpressions of @var{x} have been\n\
3124processed, and false when @code{rtx_cost} should recurse.",
3125 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
3126 hook_bool_rtx_int_int_int_intp_bool_false)
3127
3128/* Compute the cost of X, used as an address.  Never called with
3129   invalid addresses.  */
3130DEFHOOK
3131(address_cost,
3132 "This hook computes the cost of an addressing mode that contains\n\
3133@var{address}.  If not defined, the cost is computed from\n\
3134the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3135\n\
3136For most CISC machines, the default cost is a good approximation of the\n\
3137true cost of the addressing mode.  However, on RISC machines, all\n\
3138instructions normally have the same length and execution time.  Hence\n\
3139all addresses will have equal costs.\n\
3140\n\
3141In cases where more than one form of an address is known, the form with\n\
3142the lowest cost will be used.  If multiple forms have the same, lowest,\n\
3143cost, the one that is the most complex will be used.\n\
3144\n\
3145For example, suppose an address that is equal to the sum of a register\n\
3146and a constant is used twice in the same basic block.  When this macro\n\
3147is not defined, the address will be computed in a register and memory\n\
3148references will be indirect through that register.  On machines where\n\
3149the cost of the addressing mode containing the sum is no higher than\n\
3150that of a simple indirect reference, this will produce an additional\n\
3151instruction and possibly require an additional register.  Proper\n\
3152specification of this macro eliminates this overhead for such machines.\n\
3153\n\
3154This hook is never called with an invalid address.\n\
3155\n\
3156On machines where an address involving more than one register is as\n\
3157cheap as an address computation involving only one register, defining\n\
3158@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3159be live over a region of code where only one would have been if\n\
3160@code{TARGET_ADDRESS_COST} were not defined in that manner.  This effect\n\
3161should be considered in the definition of this macro.  Equivalent costs\n\
3162should probably only be given to addresses with different numbers of\n\
3163registers on machines with lots of registers.",
3164 int, (rtx address, enum machine_mode mode, addr_space_t as, bool speed),
3165 default_address_cost)
3166
3167/* Return where to allocate pseudo for a given hard register initial value.  */
3168DEFHOOK
3169(allocate_initial_value,
3170 "\n\
3171When the initial value of a hard register has been copied in a pseudo\n\
3172register, it is often not necessary to actually allocate another register\n\
3173to this pseudo register, because the original hard register or a stack slot\n\
3174it has been saved into can be used.  @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3175is called at the start of register allocation once for each hard register\n\
3176that had its initial value copied by using\n\
3177@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3178Possible values are @code{NULL_RTX}, if you don't want\n\
3179to do any special allocation, a @code{REG} rtx---that would typically be\n\
3180the hard register itself, if it is known not to be clobbered---or a\n\
3181@code{MEM}.\n\
3182If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3183it might decide to use another register anyways.\n\
3184You may use @code{current_function_is_leaf} or \n\
3185@code{REG_N_SETS} in the hook to determine if the hard\n\
3186register in question will not be clobbered.\n\
3187The default value of this hook is @code{NULL}, which disables any special\n\
3188allocation.",
3189 rtx, (rtx hard_reg), NULL)
3190
3191/* Return nonzero if evaluating UNSPEC X might cause a trap.
3192   FLAGS has the same meaning as in rtlanal.c: may_trap_p_1.  */
3193DEFHOOK
3194(unspec_may_trap_p,
3195 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3196@code{unspec_volatile} operation, might cause a trap.  Targets can use\n\
3197this hook to enhance precision of analysis for @code{unspec} and\n\
3198@code{unspec_volatile} operations.  You may call @code{may_trap_p_1}\n\
3199to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3200passed along.",
3201 int, (const_rtx x, unsigned flags),
3202 default_unspec_may_trap_p)
3203
3204/* Given a register, this hook should return a parallel of registers
3205   to represent where to find the register pieces.  Define this hook
3206   if the register and its mode are represented in Dwarf in
3207   non-contiguous locations, or if the register should be
3208   represented in more than one register in Dwarf.  Otherwise, this
3209   hook should return NULL_RTX.  */
3210DEFHOOK
3211(dwarf_register_span,
3212 "Given a register, this hook should return a parallel of registers to\n\
3213represent where to find the register pieces.  Define this hook if the\n\
3214register and its mode are represented in Dwarf in non-contiguous\n\
3215locations, or if the register should be represented in more than one\n\
3216register in Dwarf.  Otherwise, this hook should return @code{NULL_RTX}.\n\
3217If not defined, the default is to return @code{NULL_RTX}.",
3218 rtx, (rtx reg),
3219 hook_rtx_rtx_null)
3220
3221/* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3222   entries not corresponding directly to registers below
3223   FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3224   code, given the address of the table.  */
3225DEFHOOK
3226(init_dwarf_reg_sizes_extra,
3227 "If some registers are represented in Dwarf-2 unwind information in\n\
3228multiple pieces, define this hook to fill in information about the\n\
3229sizes of those pieces in the table used by the unwinder at runtime.\n\
3230It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3231filling in a single size corresponding to each hard register;\n\
3232@var{address} is the address of the table.",
3233 void, (tree address),
3234 hook_void_tree)
3235
3236/* Fetch the fixed register(s) which hold condition codes, for
3237   targets where it makes sense to look for duplicate assignments to
3238   the condition codes.  This should return true if there is such a
3239   register, false otherwise.  The arguments should be set to the
3240   fixed register numbers.  Up to two condition code registers are
3241   supported.  If there is only one for this target, the int pointed
3242   at by the second argument should be set to -1.  */
3243DEFHOOK
3244(fixed_condition_code_regs,
3245 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3246register rather than a pseudo-register to hold condition codes, the\n\
3247regular CSE passes are often not able to identify cases in which the\n\
3248hard register is set to a common value.  Use this hook to enable a\n\
3249small pass which optimizes such cases.  This hook should return true\n\
3250to enable this pass, and it should set the integers to which its\n\
3251arguments point to the hard register numbers used for condition codes.\n\
3252When there is only one such register, as is true on most systems, the\n\
3253integer pointed to by @var{p2} should be set to\n\
3254@code{INVALID_REGNUM}.\n\
3255\n\
3256The default version of this hook returns false.",
3257 bool, (unsigned int *p1, unsigned int *p2),
3258 hook_bool_uintp_uintp_false)
3259
3260/* If two condition code modes are compatible, return a condition
3261     code mode which is compatible with both, such that a comparison
3262     done in the returned mode will work for both of the original
3263     modes.  If the condition code modes are not compatible, return
3264     VOIDmode.  */
3265DEFHOOK
3266(cc_modes_compatible,
3267 "On targets which use multiple condition code modes in class\n\
3268@code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3269validly done in more than one mode.  On such a system, define this\n\
3270target hook to take two mode arguments and to return a mode in which\n\
3271both comparisons may be validly done.  If there is no such mode,\n\
3272return @code{VOIDmode}.\n\
3273\n\
3274The default version of this hook checks whether the modes are the\n\
3275same.  If they are, it returns that mode.  If they are different, it\n\
3276returns @code{VOIDmode}.",
3277 enum machine_mode, (enum machine_mode m1, enum machine_mode m2),
3278 default_cc_modes_compatible)
3279
3280/* Do machine-dependent code transformations.  Called just before
3281     delayed-branch scheduling.  */
3282DEFHOOK
3283(machine_dependent_reorg,
3284 "If non-null, this hook performs a target-specific pass over the\n\
3285instruction stream.  The compiler will run it at all optimization levels,\n\
3286just before the point at which it normally does delayed-branch scheduling.\n\
3287\n\
3288The exact purpose of the hook varies from target to target.  Some use\n\
3289it to do transformations that are necessary for correctness, such as\n\
3290laying out in-function constant pools or avoiding hardware hazards.\n\
3291Others use it as an opportunity to do some machine-dependent optimizations.\n\
3292\n\
3293You need not implement the hook if it has nothing to do.  The default\n\
3294definition is null.",
3295 void, (void), NULL)
3296
3297/* Create the __builtin_va_list type.  */
3298DEFHOOK
3299(build_builtin_va_list,
3300 "This hook returns a type node for @code{va_list} for the target.\n\
3301The default version of the hook returns @code{void*}.",
3302 tree, (void),
3303 std_build_builtin_va_list)
3304
3305/* Enumerate the va list variants.  */
3306DEFHOOK
3307(enum_va_list_p,
3308 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3309to iterate through the target specific builtin types for va_list. The\n\
3310variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3311to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3312variable.\n\
3313The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3314this macro and are set to the name of the va_list builtin type and its\n\
3315internal type.\n\
3316If the return value of this macro is zero, then there is no more element.\n\
3317Otherwise the @var{IDX} should be increased for the next call of this\n\
3318macro to iterate through all types.",
3319 int, (int idx, const char **pname, tree *ptree),
3320 NULL)
3321
3322/* Get the cfun/fndecl calling abi __builtin_va_list type.  */
3323DEFHOOK
3324(fn_abi_va_list,
3325 "This hook returns the va_list type of the calling convention specified by\n\
3326@var{fndecl}.\n\
3327The default version of this hook returns @code{va_list_type_node}.",
3328 tree, (tree fndecl),
3329 std_fn_abi_va_list)
3330
3331/* Get the __builtin_va_list type dependent on input type.  */
3332DEFHOOK
3333(canonical_va_list_type,
3334 "This hook returns the va_list type of the calling convention specified by the\n\
3335type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3336@code{NULL_TREE}.",
3337 tree, (tree type),
3338 std_canonical_va_list_type)
3339
3340/* ??? Documenting this hook requires a GFDL license grant.  */
3341DEFHOOK_UNDOC
3342(expand_builtin_va_start,
3343"Expand the @code{__builtin_va_start} builtin.",
3344 void, (tree valist, rtx nextarg), NULL)
3345
3346/* Gimplifies a VA_ARG_EXPR.  */
3347DEFHOOK
3348(gimplify_va_arg_expr,
3349 "This hook performs target-specific gimplification of\n\
3350@code{VA_ARG_EXPR}.  The first two parameters correspond to the\n\
3351arguments to @code{va_arg}; the latter two are as in\n\
3352@code{gimplify.c:gimplify_expr}.",
3353 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3354 std_gimplify_va_arg_expr)
3355
3356/* Validity-checking routines for PCH files, target-specific.
3357   get_pch_validity returns a pointer to the data to be stored,
3358   and stores the size in its argument.  pch_valid_p gets the same
3359   information back and returns NULL if the PCH is valid,
3360   or an error message if not.  */
3361DEFHOOK
3362(get_pch_validity,
3363 "This hook returns a pointer to the data needed by\n\
3364@code{TARGET_PCH_VALID_P} and sets\n\
3365@samp{*@var{sz}} to the size of the data in bytes.",
3366 void *, (size_t *sz),
3367 default_get_pch_validity)
3368
3369DEFHOOK
3370(pch_valid_p,
3371 "This hook checks whether the options used to create a PCH file are\n\
3372compatible with the current settings.  It returns @code{NULL}\n\
3373if so and a suitable error message if not.  Error messages will\n\
3374be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3375\n\
3376@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3377when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3378It's safe to assume that the data was created by the same version of the\n\
3379compiler, so no format checking is needed.\n\
3380\n\
3381The default definition of @code{default_pch_valid_p} should be\n\
3382suitable for most targets.",
3383 const char *, (const void *data, size_t sz),
3384 default_pch_valid_p)
3385
3386DEFHOOK
3387(prepare_pch_save,
3388 "Called before writing out a PCH file.  If the target has some\n\
3389garbage-collected data that needs to be in a particular state on PCH loads,\n\
3390it can use this hook to enforce that state.  Very few targets need\n\
3391to do anything here.",
3392 void, (void),
3393 hook_void_void)
3394
3395/* If nonnull, this function checks whether a PCH file with the
3396   given set of target flags can be used.  It returns NULL if so,
3397   otherwise it returns an error message.  */
3398DEFHOOK
3399(check_pch_target_flags,
3400 "If this hook is nonnull, the default implementation of\n\
3401@code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3402of @code{target_flags}.  @var{pch_flags} specifies the value that\n\
3403@code{target_flags} had when the PCH file was created.  The return\n\
3404value is the same as for @code{TARGET_PCH_VALID_P}.",
3405 const char *, (int pch_flags), NULL)
3406
3407/* True if the compiler should give an enum type only as many
3408   bytes as it takes to represent the range of possible values of
3409   that type.  */
3410DEFHOOK
3411(default_short_enums,
3412 "This target hook should return true if the compiler should give an\n\
3413@code{enum} type only as many bytes as it takes to represent the range\n\
3414of possible values of that type.  It should return false if all\n\
3415@code{enum} types should be allocated like @code{int}.\n\
3416\n\
3417The default is to return false.",
3418 bool, (void),
3419 hook_bool_void_false)
3420
3421/* This target hook returns an rtx that is used to store the address
3422   of the current frame into the built-in setjmp buffer.  */
3423DEFHOOK
3424(builtin_setjmp_frame_value,
3425 "This target hook should return an rtx that is used to store\n\
3426the address of the current frame into the built in @code{setjmp} buffer.\n\
3427The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3428machines.  One reason you may need to define this target hook is if\n\
3429@code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3430 rtx, (void),
3431 default_builtin_setjmp_frame_value)
3432
3433/* This target hook should add STRING_CST trees for any hard regs
3434   the port wishes to automatically clobber for an asm.  */
3435DEFHOOK
3436(md_asm_clobbers,
3437 "This target hook should add to @var{clobbers} @code{STRING_CST} trees for\n\
3438any hard regs the port wishes to automatically clobber for an asm.\n\
3439It should return the result of the last @code{tree_cons} used to add a\n\
3440clobber.  The @var{outputs}, @var{inputs} and @var{clobber} lists are the\n\
3441corresponding parameters to the asm and may be inspected to avoid\n\
3442clobbering a register that is an input or output of the asm.  You can use\n\
3443@code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test\n\
3444for overlap with regards to asm-declared registers.",
3445 tree, (tree outputs, tree inputs, tree clobbers),
3446 hook_tree_tree_tree_tree_3rd_identity)
3447
3448/* This target hook allows the backend to specify a calling convention
3449   in the debug information.  This function actually returns an
3450   enum dwarf_calling_convention, but because of forward declarations
3451   and not wanting to include dwarf2.h everywhere target.h is included
3452   the function is being declared as an int.  */
3453DEFHOOK
3454(dwarf_calling_convention,
3455 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3456be emitted for each function.  Instead of an integer return the enum\n\
3457value for the @code{DW_CC_} tag.",
3458 int, (const_tree function),
3459 hook_int_const_tree_0)
3460
3461/* This target hook allows the backend to emit frame-related insns that
3462   contain UNSPECs or UNSPEC_VOLATILEs.  The call frame debugging info
3463   engine will invoke it on insns of the form
3464     (set (reg) (unspec [...] UNSPEC_INDEX))
3465   and
3466     (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3467   to let the backend emit the call frame instructions.  */
3468DEFHOOK
3469(dwarf_handle_frame_unspec,
3470 "This target hook allows the backend to emit frame-related insns that\n\
3471contain UNSPECs or UNSPEC_VOLATILEs.  The DWARF 2 call frame debugging\n\
3472info engine will invoke it on insns of the form\n\
3473@smallexample\n\
3474(set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3475@end smallexample\n\
3476and\n\
3477@smallexample\n\
3478(set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3479@end smallexample\n\
3480to let the backend emit the call frame instructions.  @var{label} is\n\
3481the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3482the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3483 void, (const char *label, rtx pattern, int index), NULL)
3484
3485/* ??? Documenting this hook requires a GFDL license grant.  */
3486DEFHOOK_UNDOC
3487(stdarg_optimize_hook,
3488"Perform architecture specific checking of statements gimplified\
3489 from @code{VA_ARG_EXPR}.  @var{stmt} is the statement.  Returns true if\
3490 the statement doesn't need to be checked for @code{va_list} references.",
3491 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)
3492
3493/* This target hook allows the operating system to override the DECL
3494   that represents the external variable that contains the stack
3495   protection guard variable.  The type of this DECL is ptr_type_node.  */
3496DEFHOOK
3497(stack_protect_guard,
3498 "This hook returns a @code{DECL} node for the external variable to use\n\
3499for the stack protection guard.  This variable is initialized by the\n\
3500runtime to some random value and is used to initialize the guard value\n\
3501that is placed at the top of the local stack frame.  The type of this\n\
3502variable must be @code{ptr_type_node}.\n\
3503\n\
3504The default version of this hook creates a variable called\n\
3505@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3506 tree, (void),
3507 default_stack_protect_guard)
3508
3509/* This target hook allows the operating system to override the CALL_EXPR
3510   that is invoked when a check vs the guard variable fails.  */
3511DEFHOOK
3512(stack_protect_fail,
3513 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3514stack protect guard variable has been modified.  This expression should\n\
3515involve a call to a @code{noreturn} function.\n\
3516\n\
3517The default version of this hook invokes a function called\n\
3518@samp{__stack_chk_fail}, taking no arguments.  This function is\n\
3519normally defined in @file{libgcc2.c}.",
3520 tree, (void),
3521 default_external_stack_protect_fail)
3522
3523DEFHOOK
3524(can_use_doloop_p,
3525 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
3526and @code{doloop_begin}) for a particular loop.  @var{iterations} gives the\n\
3527exact number of iterations, or 0 if not known.  @var{iterations_max} gives\n\
3528the maximum number of iterations, or 0 if not known.  @var{loop_depth} is\n\
3529the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
3530contain innermost loops, and so on.  @var{entered_at_top} is true if the\n\
3531loop is only entered from the top.\n\
3532\n\
3533This hook is only used if @code{doloop_end} is available.  The default\n\
3534implementation returns true.  You can use @code{can_use_doloop_if_innermost}\n\
3535if the loop must be the innermost, and if there are no other restrictions.",
3536 bool, (double_int iterations, double_int iterations_max,
3537        unsigned int loop_depth, bool entered_at_top),
3538 hook_bool_dint_dint_uint_bool_true)
3539
3540/* Returns NULL if target supports the insn within a doloop block,
3541   otherwise it returns an error message.  */
3542DEFHOOK
3543(invalid_within_doloop,
3544 "\n\
3545Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3546low-overhead loop, otherwise return a string explaining why doloop\n\
3547could not be applied.\n\
3548\n\
3549Many targets use special registers for low-overhead looping. For any\n\
3550instruction that clobbers these this function should return a string indicating\n\
3551the reason why the doloop could not be applied.\n\
3552By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3553loops containing function calls or branch on table instructions.",
3554 const char *, (const_rtx insn),
3555 default_invalid_within_doloop)
3556
3557/* Returns true for a legitimate combined insn.  */
3558DEFHOOK
3559(legitimate_combined_insn,
3560"Take an instruction in @var{insn} and return @code{false} if the instruction\
3561 is not appropriate as a combination of two or more instructions.  The\
3562 default is to accept all instructions.",
3563 bool, (rtx insn),
3564 hook_bool_rtx_true)
3565
3566DEFHOOK
3567(valid_dllimport_attribute_p,
3568"@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3569 specified.  Use this hook if the target needs to add extra validation\
3570 checks to @code{handle_dll_attribute}.",
3571 bool, (const_tree decl),
3572 hook_bool_const_tree_true)
3573
3574/* If non-zero, align constant anchors in CSE to a multiple of this
3575   value.  */
3576DEFHOOKPOD
3577(const_anchor,
3578 "On some architectures it can take multiple instructions to synthesize\n\
3579a constant.  If there is another constant already in a register that\n\
3580is close enough in value then it is preferable that the new constant\n\
3581is computed from this register using immediate addition or\n\
3582subtraction.  We accomplish this through CSE.  Besides the value of\n\
3583the constant we also add a lower and an upper constant anchor to the\n\
3584available expressions.  These are then queried when encountering new\n\
3585constants.  The anchors are computed by rounding the constant up and\n\
3586down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3587@code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3588accepted by immediate-add plus one.  We currently assume that the\n\
3589value of @code{TARGET_CONST_ANCHOR} is a power of 2.  For example, on\n\
3590MIPS, where add-immediate takes a 16-bit signed value,\n\
3591@code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}.  The default value\n\
3592is zero, which disables this optimization.",
3593 unsigned HOST_WIDE_INT, 0)
3594
3595/* Defines, which target-dependent bits (upper 16) are used by port  */
3596DEFHOOK
3597(memmodel_check,
3598 "Validate target specific memory model mask bits. When NULL no target specific\n\
3599memory model bits are allowed.",
3600 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
3601
3602/* Defines an offset bitwise ored into shifted address to get corresponding
3603   Address Sanitizer shadow address, or -1 if Address Sanitizer is not
3604   supported by the target.  */
3605DEFHOOK
3606(asan_shadow_offset,
3607 "Return the offset bitwise ored into shifted address to get corresponding\n\
3608Address Sanitizer shadow memory address.  NULL if Address Sanitizer is not\n\
3609supported by the target.",
3610 unsigned HOST_WIDE_INT, (void),
3611 NULL)
3612
3613/* Functions relating to calls - argument passing, returns, etc.  */
3614/* Members of struct call have no special macro prefix.  */
3615HOOK_VECTOR (TARGET_CALLS, calls)
3616
3617DEFHOOK
3618(promote_function_mode,
3619 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
3620function return values.  The target hook should return the new mode\n\
3621and possibly change @code{*@var{punsignedp}} if the promotion should\n\
3622change signedness.  This function is called only for scalar @emph{or\n\
3623pointer} types.\n\
3624\n\
3625@var{for_return} allows to distinguish the promotion of arguments and\n\
3626return values.  If it is @code{1}, a return value is being promoted and\n\
3627@code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
3628If it is @code{2}, the returned mode should be that of the register in\n\
3629which an incoming parameter is copied, or the outgoing result is computed;\n\
3630then the hook should return the same mode as @code{promote_mode}, though\n\
3631the signedness may be different.\n\
3632\n\
3633@var{type} can be NULL when promoting function arguments of libcalls.\n\
3634\n\
3635The default is to not promote arguments and return values.  You can\n\
3636also define the hook to @code{default_promote_function_mode_always_promote}\n\
3637if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
3638 enum machine_mode, (const_tree type, enum machine_mode mode, int *punsignedp,
3639                     const_tree funtype, int for_return),
3640 default_promote_function_mode)
3641
3642DEFHOOK
3643(promote_prototypes,
3644 "This target hook returns @code{true} if an argument declared in a\n\
3645prototype as an integral type smaller than @code{int} should actually be\n\
3646passed as an @code{int}.  In addition to avoiding errors in certain\n\
3647cases of mismatch, it also makes for better code on certain machines.\n\
3648The default is to not promote prototypes.",
3649 bool, (const_tree fntype),
3650 hook_bool_const_tree_false)
3651
3652DEFHOOK
3653(struct_value_rtx,
3654 "This target hook should return the location of the structure value\n\
3655address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
3656passed as an ``invisible'' first argument.  Note that @var{fndecl} may\n\
3657be @code{NULL}, for libcalls.  You do not need to define this target\n\
3658hook if the address is always passed as an ``invisible'' first\n\
3659argument.\n\
3660\n\
3661On some architectures the place where the structure value address\n\
3662is found by the called function is not the same place that the\n\
3663caller put it.  This can be due to register windows, or it could\n\
3664be because the function prologue moves it to a different place.\n\
3665@var{incoming} is @code{1} or @code{2} when the location is needed in\n\
3666the context of the called function, and @code{0} in the context of\n\
3667the caller.\n\
3668\n\
3669If @var{incoming} is nonzero and the address is to be found on the\n\
3670stack, return a @code{mem} which refers to the frame pointer. If\n\
3671@var{incoming} is @code{2}, the result is being used to fetch the\n\
3672structure value address at the beginning of a function.  If you need\n\
3673to emit adjusting code, you should do it at this point.",
3674 rtx, (tree fndecl, int incoming),
3675 hook_rtx_tree_int_null)
3676DEFHOOK
3677(return_in_memory,
3678 "This target hook should return a nonzero value to say to return the\n\
3679function value in memory, just as large structures are always returned.\n\
3680Here @var{type} will be the data type of the value, and @var{fntype}\n\
3681will be the type of the function doing the returning, or @code{NULL} for\n\
3682libcalls.\n\
3683\n\
3684Note that values of mode @code{BLKmode} must be explicitly handled\n\
3685by this function.  Also, the option @option{-fpcc-struct-return}\n\
3686takes effect regardless of this macro.  On most systems, it is\n\
3687possible to leave the hook undefined; this causes a default\n\
3688definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
3689values, and 0 otherwise.\n\
3690\n\
3691Do not use this hook to indicate that structures and unions should always\n\
3692be returned in memory.  You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
3693to indicate this.",
3694 bool, (const_tree type, const_tree fntype),
3695 default_return_in_memory)
3696
3697DEFHOOK
3698(return_in_msb,
3699 "This hook should return true if values of type @var{type} are returned\n\
3700at the most significant end of a register (in other words, if they are\n\
3701padded at the least significant end).  You can assume that @var{type}\n\
3702is returned in a register; the caller is required to check this.\n\
3703\n\
3704Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
3705be able to hold the complete return value.  For example, if a 1-, 2-\n\
3706or 3-byte structure is returned at the most significant end of a\n\
37074-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
3708@code{SImode} rtx.",
3709 bool, (const_tree type),
3710 hook_bool_const_tree_false)
3711
3712/* Return true if a parameter must be passed by reference.  TYPE may
3713   be null if this is a libcall.  CA may be null if this query is
3714   from __builtin_va_arg.  */
3715DEFHOOK
3716(pass_by_reference,
3717 "This target hook should return @code{true} if an argument at the\n\
3718position indicated by @var{cum} should be passed by reference.  This\n\
3719predicate is queried after target independent reasons for being\n\
3720passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
3721\n\
3722If the hook returns true, a copy of that argument is made in memory and a\n\
3723pointer to the argument is passed instead of the argument itself.\n\
3724The pointer is passed in whatever way is appropriate for passing a pointer\n\
3725to that type.",
3726 bool,
3727 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3728 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3729
3730DEFHOOK
3731(expand_builtin_saveregs,
3732 "If defined, this hook produces the machine-specific code for a call to\n\
3733@code{__builtin_saveregs}.  This code will be moved to the very\n\
3734beginning of the function, before any parameter access are made.  The\n\
3735return value of this function should be an RTX that contains the value\n\
3736to use as the return of @code{__builtin_saveregs}.",
3737 rtx, (void),
3738 default_expand_builtin_saveregs)
3739
3740/* Returns pretend_argument_size.  */
3741DEFHOOK
3742(setup_incoming_varargs,
3743 "This target hook offers an alternative to using\n\
3744@code{__builtin_saveregs} and defining the hook\n\
3745@code{TARGET_EXPAND_BUILTIN_SAVEREGS}.  Use it to store the anonymous\n\
3746register arguments into the stack so that all the arguments appear to\n\
3747have been passed consecutively on the stack.  Once this is done, you can\n\
3748use the standard implementation of varargs that works for machines that\n\
3749pass all their arguments on the stack.\n\
3750\n\
3751The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
3752structure, containing the values that are obtained after processing the\n\
3753named arguments.  The arguments @var{mode} and @var{type} describe the\n\
3754last named argument---its machine mode and its data type as a tree node.\n\
3755\n\
3756The target hook should do two things: first, push onto the stack all the\n\
3757argument registers @emph{not} used for the named arguments, and second,\n\
3758store the size of the data thus pushed into the @code{int}-valued\n\
3759variable pointed to by @var{pretend_args_size}.  The value that you\n\
3760store here will serve as additional offset for setting up the stack\n\
3761frame.\n\
3762\n\
3763Because you must generate code to push the anonymous arguments at\n\
3764compile time without knowing their data types,\n\
3765@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
3766have just a single category of argument register and use it uniformly\n\
3767for all data types.\n\
3768\n\
3769If the argument @var{second_time} is nonzero, it means that the\n\
3770arguments of the function are being analyzed for the second time.  This\n\
3771happens for an inline function, which is not actually compiled until the\n\
3772end of the source file.  The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
3773not generate any instructions in this case.",
3774 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
3775        int *pretend_args_size, int second_time),
3776 default_setup_incoming_varargs)
3777
3778DEFHOOK
3779(strict_argument_naming,
3780 "Define this hook to return @code{true} if the location where a function\n\
3781argument is passed depends on whether or not it is a named argument.\n\
3782\n\
3783This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
3784is set for varargs and stdarg functions.  If this hook returns\n\
3785@code{true}, the @var{named} argument is always true for named\n\
3786arguments, and false for unnamed arguments.  If it returns @code{false},\n\
3787but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
3788then all arguments are treated as named.  Otherwise, all named arguments\n\
3789except the last are treated as named.\n\
3790\n\
3791You need not define this hook if it always returns @code{false}.",
3792 bool, (cumulative_args_t ca),
3793 hook_bool_CUMULATIVE_ARGS_false)
3794
3795/* Returns true if we should use
3796   targetm.calls.setup_incoming_varargs() and/or
3797   targetm.calls.strict_argument_naming().  */
3798DEFHOOK
3799(pretend_outgoing_varargs_named,
3800 "If you need to conditionally change ABIs so that one works with\n\
3801@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
3802@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
3803defined, then define this hook to return @code{true} if\n\
3804@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
3805Otherwise, you should not define this hook.",
3806 bool, (cumulative_args_t ca),
3807 default_pretend_outgoing_varargs_named)
3808
3809/* Given a complex type T, return true if a parameter of type T
3810   should be passed as two scalars.  */
3811DEFHOOK
3812(split_complex_arg,
3813 "This hook should return true if parameter of type @var{type} are passed\n\
3814as two scalar parameters.  By default, GCC will attempt to pack complex\n\
3815arguments into the target's word size.  Some ABIs require complex arguments\n\
3816to be split and treated as their individual components.  For example, on\n\
3817AIX64, complex floats should be passed in a pair of floating point\n\
3818registers, even though a complex float would fit in one 64-bit floating\n\
3819point register.\n\
3820\n\
3821The default value of this hook is @code{NULL}, which is treated as always\n\
3822false.",
3823 bool, (const_tree type), NULL)
3824
3825/* Return true if type T, mode MODE, may not be passed in registers,
3826   but must be passed on the stack.  */
3827/* ??? This predicate should be applied strictly after pass-by-reference.
3828   Need audit to verify that this is the case.  */
3829DEFHOOK
3830(must_pass_in_stack,
3831 "This target hook should return @code{true} if we should not pass @var{type}\n\
3832solely in registers.  The file @file{expr.h} defines a\n\
3833definition that is usually appropriate, refer to @file{expr.h} for additional\n\
3834documentation.",
3835 bool, (enum machine_mode mode, const_tree type),
3836 must_pass_in_stack_var_size_or_pad)
3837
3838/* Return true if type TYPE, mode MODE, which is passed by reference,
3839   should have the object copy generated by the callee rather than
3840   the caller.  It is never called for TYPE requiring constructors.  */
3841DEFHOOK
3842(callee_copies,
3843 "The function argument described by the parameters to this hook is\n\
3844known to be passed by reference.  The hook should return true if the\n\
3845function argument should be copied by the callee instead of copied\n\
3846by the caller.\n\
3847\n\
3848For any argument for which the hook returns true, if it can be\n\
3849determined that the argument is not modified, then a copy need\n\
3850not be generated.\n\
3851\n\
3852The default version of this hook always returns false.",
3853 bool,
3854 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3855 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3856
3857/* Return zero for arguments passed entirely on the stack or entirely
3858   in registers.  If passed in both, return the number of bytes passed
3859   in registers; the balance is therefore passed on the stack.  */
3860DEFHOOK
3861(arg_partial_bytes,
3862 "This target hook returns the number of bytes at the beginning of an\n\
3863argument that must be put in registers.  The value must be zero for\n\
3864arguments that are passed entirely in registers or that are entirely\n\
3865pushed on the stack.\n\
3866\n\
3867On some machines, certain arguments must be passed partially in\n\
3868registers and partially in memory.  On these machines, typically the\n\
3869first few words of arguments are passed in registers, and the rest\n\
3870on the stack.  If a multi-word argument (a @code{double} or a\n\
3871structure) crosses that boundary, its first few words must be passed\n\
3872in registers and the rest must be pushed.  This macro tells the\n\
3873compiler when this occurs, and how many bytes should go in registers.\n\
3874\n\
3875@code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
3876register to be used by the caller for this argument; likewise\n\
3877@code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
3878 int, (cumulative_args_t cum, enum machine_mode mode, tree type, bool named),
3879 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
3880
3881/* Update the state in CA to advance past an argument in the
3882   argument list.  The values MODE, TYPE, and NAMED describe that
3883   argument.  */
3884DEFHOOK
3885(function_arg_advance,
3886 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
3887advance past an argument in the argument list.  The values @var{mode},\n\
3888@var{type} and @var{named} describe that argument.  Once this is done,\n\
3889the variable @var{cum} is suitable for analyzing the @emph{following}\n\
3890argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
3891\n\
3892This hook need not do anything if the argument in question was passed\n\
3893on the stack.  The compiler knows how to track the amount of stack space\n\
3894used for arguments without any special help.",
3895 void,
3896 (cumulative_args_t ca, enum machine_mode mode, const_tree type, bool named),
3897 default_function_arg_advance)
3898
3899/* Return zero if the argument described by the state of CA should
3900   be placed on a stack, or a hard register in which to store the
3901   argument.  The values MODE, TYPE, and NAMED describe that
3902   argument.  */
3903DEFHOOK
3904(function_arg,
3905 "Return an RTX indicating whether a function argument is passed in a\n\
3906register and if so, which register.\n\
3907\n\
3908The arguments are @var{ca}, which summarizes all the previous\n\
3909arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
3910the data type of the argument as a tree node or 0 if that is not known\n\
3911(which happens for C support library functions); and @var{named},\n\
3912which is @code{true} for an ordinary argument and @code{false} for\n\
3913nameless arguments that correspond to @samp{@dots{}} in the called\n\
3914function's prototype.  @var{type} can be an incomplete type if a\n\
3915syntax error has previously occurred.\n\
3916\n\
3917The return value is usually either a @code{reg} RTX for the hard\n\
3918register in which to pass the argument, or zero to pass the argument\n\
3919on the stack.\n\
3920\n\
3921The value of the expression can also be a @code{parallel} RTX@.  This is\n\
3922used when an argument is passed in multiple locations.  The mode of the\n\
3923@code{parallel} should be the mode of the entire argument.  The\n\
3924@code{parallel} holds any number of @code{expr_list} pairs; each one\n\
3925describes where part of the argument is passed.  In each\n\
3926@code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
3927register in which to pass this part of the argument, and the mode of the\n\
3928register RTX indicates how large this part of the argument is.  The\n\
3929second operand of the @code{expr_list} is a @code{const_int} which gives\n\
3930the offset in bytes into the entire argument of where this part starts.\n\
3931As a special exception the first @code{expr_list} in the @code{parallel}\n\
3932RTX may have a first operand of zero.  This indicates that the entire\n\
3933argument is also stored on the stack.\n\
3934\n\
3935The last time this hook is called, it is called with @code{MODE ==\n\
3936VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
3937pattern as operands 2 and 3 respectively.\n\
3938\n\
3939@cindex @file{stdarg.h} and register arguments\n\
3940The usual way to make the ISO library @file{stdarg.h} work on a\n\
3941machine where some arguments are usually passed in registers, is to\n\
3942cause nameless arguments to be passed on the stack instead.  This is\n\
3943done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
3944@var{named} is @code{false}.\n\
3945\n\
3946@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
3947@cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
3948You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
3949in the definition of this macro to determine if this argument is of a\n\
3950type that must be passed in the stack.  If @code{REG_PARM_STACK_SPACE}\n\
3951is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
3952argument, the compiler will abort.  If @code{REG_PARM_STACK_SPACE} is\n\
3953defined, the argument will be computed in the stack and then loaded into\n\
3954a register.",
3955 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3956       bool named),
3957 default_function_arg)
3958
3959/* Likewise, but for machines with register windows.  Return the
3960   location where the argument will appear to the callee.  */
3961DEFHOOK
3962(function_incoming_arg,
3963 "Define this hook if the target machine has ``register windows'', so\n\
3964that the register in which a function sees an arguments is not\n\
3965necessarily the same as the one in which the caller passed the\n\
3966argument.\n\
3967\n\
3968For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
3969which the caller passes the value, and\n\
3970@code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
3971fashion to tell the function being called where the arguments will\n\
3972arrive.\n\
3973\n\
3974If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
3975@code{TARGET_FUNCTION_ARG} serves both purposes.",
3976 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3977       bool named),
3978 default_function_incoming_arg)
3979
3980DEFHOOK
3981(function_arg_boundary,
3982 "This hook returns the alignment boundary, in bits, of an argument\n\
3983with the specified mode and type.  The default hook returns\n\
3984@code{PARM_BOUNDARY} for all arguments.",
3985 unsigned int, (enum machine_mode mode, const_tree type),
3986 default_function_arg_boundary)
3987
3988DEFHOOK
3989(function_arg_round_boundary,
3990 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
3991which is the default value for this hook.  You can define this hook to\n\
3992return a different value if an argument size must be rounded to a larger\n\
3993value.",
3994 unsigned int, (enum machine_mode mode, const_tree type),
3995 default_function_arg_round_boundary)
3996
3997/* Return the diagnostic message string if function without a prototype
3998   is not allowed for this 'val' argument; NULL otherwise. */
3999DEFHOOK
4000(invalid_arg_for_unprototyped_fn,
4001 "If defined, this macro returns the diagnostic message when it is\n\
4002illegal to pass argument @var{val} to function @var{funcdecl}\n\
4003with prototype @var{typelist}.",
4004 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4005 hook_invalid_arg_for_unprototyped_fn)
4006
4007/* Return an rtx for the return value location of the function
4008   specified by FN_DECL_OR_TYPE with a return type of RET_TYPE.  */
4009DEFHOOK
4010(function_value,
4011 "\n\
4012Define this to return an RTX representing the place where a function\n\
4013returns or receives a value of data type @var{ret_type}, a tree node\n\
4014representing a data type.  @var{fn_decl_or_type} is a tree node\n\
4015representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4016function being called.  If @var{outgoing} is false, the hook should\n\
4017compute the register in which the caller will see the return value.\n\
4018Otherwise, the hook should return an RTX representing the place where\n\
4019a function returns a value.\n\
4020\n\
4021On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4022(Actually, on most machines, scalar values are returned in the same\n\
4023place regardless of mode.)  The value of the expression is usually a\n\
4024@code{reg} RTX for the hard register where the return value is stored.\n\
4025The value can also be a @code{parallel} RTX, if the return value is in\n\
4026multiple places.  See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4027@code{parallel} form.   Note that the callee will populate every\n\
4028location specified in the @code{parallel}, but if the first element of\n\
4029the @code{parallel} contains the whole return value, callers will use\n\
4030that element as the canonical location and ignore the others.  The m68k\n\
4031port uses this type of @code{parallel} to return pointers in both\n\
4032@samp{%a0} (the canonical location) and @samp{%d0}.\n\
4033\n\
4034If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4035the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4036@var{valtype} is a scalar type.\n\
4037\n\
4038If the precise function being called is known, @var{func} is a tree\n\
4039node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4040pointer.  This makes it possible to use a different value-returning\n\
4041convention for specific functions when all their calls are\n\
4042known.\n\
4043\n\
4044Some target machines have ``register windows'' so that the register in\n\
4045which a function returns its value is not the same as the one in which\n\
4046the caller sees the value.  For such machines, you should return\n\
4047different RTX depending on @var{outgoing}.\n\
4048\n\
4049@code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4050aggregate data types, because these are returned in another way.  See\n\
4051@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4052 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4053 default_function_value)
4054
4055/* Return the rtx for the result of a libcall of mode MODE,
4056   calling the function FN_NAME.  */
4057DEFHOOK
4058(libcall_value,
4059 "Define this hook if the back-end needs to know the name of the libcall\n\
4060function in order to determine where the result should be returned.\n\
4061\n\
4062The mode of the result is given by @var{mode} and the name of the called\n\
4063library function is given by @var{fun}.  The hook should return an RTX\n\
4064representing the place where the library function result will be returned.\n\
4065\n\
4066If this hook is not defined, then LIBCALL_VALUE will be used.",
4067 rtx, (enum machine_mode mode, const_rtx fun),
4068 default_libcall_value)
4069
4070/* Return true if REGNO is a possible register number for
4071   a function value as seen by the caller.  */
4072DEFHOOK
4073(function_value_regno_p,
4074 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4075register in which the values of called function may come back.\n\
4076\n\
4077A register whose use for returning values is limited to serving as the\n\
4078second of a pair (for a value of type @code{double}, say) need not be\n\
4079recognized by this target hook.\n\
4080\n\
4081If the machine has register windows, so that the caller and the called\n\
4082function use different registers for the return value, this target hook\n\
4083should recognize only the caller's register numbers.\n\
4084\n\
4085If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4086 bool, (const unsigned int regno),
4087 default_function_value_regno_p)
4088
4089/* ??? Documenting this hook requires a GFDL license grant.  */
4090DEFHOOK_UNDOC
4091(internal_arg_pointer,
4092"Return an rtx for the argument pointer incoming to the\
4093 current function.",
4094 rtx, (void),
4095 default_internal_arg_pointer)
4096
4097/* Update the current function stack boundary if needed.  */
4098DEFHOOK
4099(update_stack_boundary,
4100 "Define this macro to update the current function stack boundary if\n\
4101necessary.",
4102 void, (void), NULL)
4103
4104/* Handle stack alignment and return an rtx for Dynamic Realign
4105   Argument Pointer if necessary.  */
4106DEFHOOK
4107(get_drap_rtx,
4108 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4109different argument pointer register is needed to access the function's\n\
4110argument list due to stack realignment.  Return @code{NULL} if no DRAP\n\
4111is needed.",
4112 rtx, (void), NULL)
4113
4114/* Return true if all function parameters should be spilled to the
4115   stack.  */
4116DEFHOOK
4117(allocate_stack_slots_for_args,
4118 "When optimization is disabled, this hook indicates whether or not\n\
4119arguments should be allocated to stack slots.  Normally, GCC allocates\n\
4120stacks slots for arguments when not optimizing in order to make\n\
4121debugging easier.  However, when a function is declared with\n\
4122@code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4123cannot safely move arguments from the registers in which they are passed\n\
4124to the stack.  Therefore, this hook should return true in general, but\n\
4125false for naked functions.  The default implementation always returns true.",
4126 bool, (void),
4127 hook_bool_void_true)
4128
4129/* Return an rtx for the static chain for FNDECL.  If INCOMING_P is true,
4130       then it should be for the callee; otherwise for the caller.  */
4131DEFHOOK
4132(static_chain,
4133 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4134targets that may use different static chain locations for different\n\
4135nested functions.  This may be required if the target has function\n\
4136attributes that affect the calling conventions of the function and\n\
4137those calling conventions use different static chain locations.\n\
4138\n\
4139The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4140\n\
4141If the static chain is passed in memory, this hook should be used to\n\
4142provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4143Often the @code{mem} expression as seen by the caller will be at an offset\n\
4144from the stack pointer and the @code{mem} expression as seen by the callee\n\
4145will be at an offset from the frame pointer.\n\
4146@findex stack_pointer_rtx\n\
4147@findex frame_pointer_rtx\n\
4148@findex arg_pointer_rtx\n\
4149The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4150@code{arg_pointer_rtx} will have been initialized and should be used\n\
4151to refer to those items.",
4152 rtx, (const_tree fndecl, bool incoming_p),
4153 default_static_chain)
4154
4155/* Fill in the trampoline at MEM with a call to FNDECL and a
4156   static chain value of CHAIN.  */
4157DEFHOOK
4158(trampoline_init,
4159 "This hook is called to initialize a trampoline.\n\
4160@var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4161is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4162RTX for the static chain value that should be passed to the function\n\
4163when it is called.\n\
4164\n\
4165If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4166first thing this hook should do is emit a block move into @var{m_tramp}\n\
4167from the memory block returned by @code{assemble_trampoline_template}.\n\
4168Note that the block move need only cover the constant parts of the\n\
4169trampoline.  If the target isolates the variable parts of the trampoline\n\
4170to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4171\n\
4172If the target requires any other actions, such as flushing caches or\n\
4173enabling stack execution, these actions should be performed after\n\
4174initializing the trampoline proper.",
4175 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4176 default_trampoline_init)
4177
4178/* Adjust the address of the trampoline in a target-specific way.  */
4179DEFHOOK
4180(trampoline_adjust_address,
4181 "This hook should perform any machine-specific adjustment in\n\
4182the address of the trampoline.  Its argument contains the address of the\n\
4183memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}.  In case\n\
4184the address to be used for a function call should be different from the\n\
4185address at which the template was stored, the different address should\n\
4186be returned; otherwise @var{addr} should be returned unchanged.\n\
4187If this hook is not defined, @var{addr} will be used for function calls.",
4188 rtx, (rtx addr), NULL)
4189
4190/* Return the number of bytes of its own arguments that a function
4191   pops on returning, or 0 if the function pops no arguments and the
4192   caller must therefore pop them all after the function returns.  */
4193/* ??? tm.texi has no types for the parameters.  */
4194DEFHOOK
4195(return_pops_args,
4196 "This target hook returns the number of bytes of its own arguments that\n\
4197a function pops on returning, or 0 if the function pops no arguments\n\
4198and the caller must therefore pop them all after the function returns.\n\
4199\n\
4200@var{fundecl} is a C variable whose value is a tree node that describes\n\
4201the function in question.  Normally it is a node of type\n\
4202@code{FUNCTION_DECL} that describes the declaration of the function.\n\
4203From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4204\n\
4205@var{funtype} is a C variable whose value is a tree node that\n\
4206describes the function in question.  Normally it is a node of type\n\
4207@code{FUNCTION_TYPE} that describes the data type of the function.\n\
4208From this it is possible to obtain the data types of the value and\n\
4209arguments (if known).\n\
4210\n\
4211When a call to a library function is being considered, @var{fundecl}\n\
4212will contain an identifier node for the library function.  Thus, if\n\
4213you need to distinguish among various library functions, you can do so\n\
4214by their names.  Note that ``library function'' in this context means\n\
4215a function used to perform arithmetic, whose name is known specially\n\
4216in the compiler and was not mentioned in the C code being compiled.\n\
4217\n\
4218@var{size} is the number of bytes of arguments passed on the\n\
4219stack.  If a variable number of bytes is passed, it is zero, and\n\
4220argument popping will always be the responsibility of the calling function.\n\
4221\n\
4222On the VAX, all functions always pop their arguments, so the definition\n\
4223of this macro is @var{size}.  On the 68000, using the standard\n\
4224calling convention, no functions pop their arguments, so the value of\n\
4225the macro is always 0 in this case.  But an alternative calling\n\
4226convention is available in which functions that take a fixed number of\n\
4227arguments pop them but other functions (such as @code{printf}) pop\n\
4228nothing (the caller pops all).  When this convention is in use,\n\
4229@var{funtype} is examined to determine whether a function takes a fixed\n\
4230number of arguments.",
4231 int, (tree fundecl, tree funtype, int size),
4232 default_return_pops_args)
4233
4234/* Return a mode wide enough to copy any function value that might be
4235   returned.  */
4236DEFHOOK
4237(get_raw_result_mode,
4238 "This target hook returns the mode to be used when accessing raw return\
4239 registers in @code{__builtin_return}.  Define this macro if the value\
4240 in @var{reg_raw_mode} is not correct.",
4241 enum machine_mode, (int regno),
4242 default_get_reg_raw_mode)
4243
4244/* Return a mode wide enough to copy any argument value that might be
4245   passed.  */
4246DEFHOOK
4247(get_raw_arg_mode,
4248 "This target hook returns the mode to be used when accessing raw argument\
4249 registers in @code{__builtin_apply_args}.  Define this macro if the value\
4250 in @var{reg_raw_mode} is not correct.",
4251 enum machine_mode, (int regno),
4252 default_get_reg_raw_mode)
4253
4254HOOK_VECTOR_END (calls)
4255
4256/* Return the diagnostic message string if conversion from FROMTYPE
4257   to TOTYPE is not allowed, NULL otherwise.  */
4258DEFHOOK
4259(invalid_conversion,
4260 "If defined, this macro returns the diagnostic message when it is\n\
4261invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4262if validity should be determined by the front end.",
4263 const char *, (const_tree fromtype, const_tree totype),
4264 hook_constcharptr_const_tree_const_tree_null)
4265
4266/* Return the diagnostic message string if the unary operation OP is
4267   not permitted on TYPE, NULL otherwise.  */
4268DEFHOOK
4269(invalid_unary_op,
4270 "If defined, this macro returns the diagnostic message when it is\n\
4271invalid to apply operation @var{op} (where unary plus is denoted by\n\
4272@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4273if validity should be determined by the front end.",
4274 const char *, (int op, const_tree type),
4275 hook_constcharptr_int_const_tree_null)
4276
4277/* Return the diagnostic message string if the binary operation OP
4278   is not permitted on TYPE1 and TYPE2, NULL otherwise.  */
4279DEFHOOK
4280(invalid_binary_op,
4281 "If defined, this macro returns the diagnostic message when it is\n\
4282invalid to apply operation @var{op} to operands of types @var{type1}\n\
4283and @var{type2}, or @code{NULL} if validity should be determined by\n\
4284the front end.",
4285 const char *, (int op, const_tree type1, const_tree type2),
4286 hook_constcharptr_int_const_tree_const_tree_null)
4287
4288/* Return the diagnostic message string if TYPE is not valid as a
4289   function parameter type, NULL otherwise.  */
4290DEFHOOK
4291(invalid_parameter_type,
4292 "If defined, this macro returns the diagnostic message when it is\n\
4293invalid for functions to include parameters of type @var{type},\n\
4294or @code{NULL} if validity should be determined by\n\
4295the front end.  This is currently used only by the C and C++ front ends.",
4296 const char *, (const_tree type),
4297 hook_constcharptr_const_tree_null)
4298
4299/* Return the diagnostic message string if TYPE is not valid as a
4300   function return type, NULL otherwise.  */
4301DEFHOOK
4302(invalid_return_type,
4303 "If defined, this macro returns the diagnostic message when it is\n\
4304invalid for functions to have return type @var{type},\n\
4305or @code{NULL} if validity should be determined by\n\
4306the front end.  This is currently used only by the C and C++ front ends.",
4307 const char *, (const_tree type),
4308 hook_constcharptr_const_tree_null)
4309
4310/* If values of TYPE are promoted to some other type when used in
4311   expressions (analogous to the integer promotions), return that type,
4312   or NULL_TREE otherwise.  */
4313DEFHOOK
4314(promoted_type,
4315 "If defined, this target hook returns the type to which values of\n\
4316@var{type} should be promoted when they appear in expressions,\n\
4317analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4318front end's normal promotion rules.  This hook is useful when there are\n\
4319target-specific types with special promotion rules.\n\
4320This is currently used only by the C and C++ front ends.",
4321 tree, (const_tree type),
4322 hook_tree_const_tree_null)
4323
4324/* Convert EXPR to TYPE, if target-specific types with special conversion
4325   rules are involved.  Return the converted expression, or NULL to apply
4326   the standard conversion rules.  */
4327DEFHOOK
4328(convert_to_type,
4329 "If defined, this hook returns the result of converting @var{expr} to\n\
4330@var{type}.  It should return the converted expression,\n\
4331or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4332This hook is useful when there are target-specific types with special\n\
4333conversion rules.\n\
4334This is currently used only by the C and C++ front ends.",
4335 tree, (tree type, tree expr),
4336 hook_tree_tree_tree_null)
4337
4338/* Return true if we use LRA instead of reload.  */
4339DEFHOOK
4340(lra_p,
4341 "A target hook which returns true if we use LRA instead of reload pass.\
4342  It means that LRA was ported to the target.\
4343  \
4344  The default version of this target hook returns always false.",
4345 bool, (void),
4346 default_lra_p)
4347
4348/* Return register priority of given hard regno for the current target.  */
4349DEFHOOK
4350(register_priority,
4351 "A target hook which returns the register priority number to which the\
4352  register @var{hard_regno} belongs to.  The bigger the number, the\
4353  more preferable the hard register usage (when all other conditions are\
4354  the same).  This hook can be used to prefer some hard register over\
4355  others in LRA.  For example, some x86-64 register usage needs\
4356  additional prefix which makes instructions longer.  The hook can\
4357  return lower priority number for such registers make them less favorable\
4358  and as result making the generated code smaller.\
4359  \
4360  The default version of this target hook returns always zero.",
4361 int, (int),
4362 default_register_priority)
4363
4364/* Return true if we need register usage leveling.  */
4365DEFHOOK
4366(register_usage_leveling_p,
4367 "A target hook which returns true if we need register usage leveling.\
4368  That means if a few hard registers are equally good for the\
4369  assignment, we choose the least used hard register.  The register\
4370  usage leveling may be profitable for some targets.  Don't use the\
4371  usage leveling for targets with conditional execution or targets\
4372  with big register files as it hurts if-conversion and cross-jumping\
4373  optimizations.\
4374  \
4375  The default version of this target hook returns always false.",
4376 bool, (void),
4377 default_register_usage_leveling_p)
4378
4379/* Return true if maximal address displacement can be different.  */
4380DEFHOOK
4381(different_addr_displacement_p,
4382 "A target hook which returns true if an address with the same structure\
4383  can have different maximal legitimate displacement.  For example, the\
4384  displacement can depend on memory mode or on operand combinations in\
4385  the insn.\
4386  \
4387  The default version of this target hook returns always false.",
4388 bool, (void),
4389 default_different_addr_displacement_p)
4390
4391/* Determine class for spilling pseudos of given mode into registers
4392   instead of memory.  */
4393DEFHOOK
4394(spill_class,
4395 "This hook defines a class of registers which could be used for spilling\
4396  pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4397  should be used.  Not defining this hook is equivalent to returning\
4398  @code{NO_REGS} for all inputs.",
4399 reg_class_t, (reg_class_t, enum machine_mode),
4400 NULL)
4401
4402DEFHOOK
4403(cstore_mode,
4404 "This hook defines the machine mode to use for the boolean result of\
4405  conditional store patterns.  The ICODE argument is the instruction code\
4406  for the cstore being performed.  Not definiting this hook is the same\
4407  as accepting the mode encoded into operand 0 of the cstore expander\
4408  patterns.",
4409  enum machine_mode, (enum insn_code icode),
4410  default_cstore_mode)
4411
4412/* True if a structure, union or array with MODE containing FIELD should
4413   be accessed using BLKmode.  */
4414DEFHOOK
4415(member_type_forces_blk,
4416 "Return true if a structure, union or array containing @var{field} should\n\
4417be accessed using @code{BLKMODE}.\n\
4418\n\
4419If @var{field} is the only field in the structure, @var{mode} is its\n\
4420mode, otherwise @var{mode} is VOIDmode.  @var{mode} is provided in the\n\
4421case where structures of one field would require the structure's mode to\n\
4422retain the field's mode.\n\
4423\n\
4424Normally, this is not needed.",
4425 bool, (const_tree field, enum machine_mode mode),
4426 default_member_type_forces_blk)
4427
4428/* Return the class for a secondary reload, and fill in extra information.  */
4429DEFHOOK
4430(secondary_reload,
4431 "Many machines have some registers that cannot be copied directly to or\n\
4432from memory or even from other types of registers.  An example is the\n\
4433@samp{MQ} register, which on most machines, can only be copied to or\n\
4434from general registers, but not memory.  Below, we shall be using the\n\
4435term 'intermediate register' when a move operation cannot be performed\n\
4436directly, but has to be done by copying the source into the intermediate\n\
4437register first, and then copying the intermediate register to the\n\
4438destination.  An intermediate register always has the same mode as\n\
4439source and destination.  Since it holds the actual value being copied,\n\
4440reload might apply optimizations to re-use an intermediate register\n\
4441and eliding the copy from the source when it can determine that the\n\
4442intermediate register still holds the required value.\n\
4443\n\
4444Another kind of secondary reload is required on some machines which\n\
4445allow copying all registers to and from memory, but require a scratch\n\
4446register for stores to some memory locations (e.g., those with symbolic\n\
4447address on the RT, and those with certain symbolic address on the SPARC\n\
4448when compiling PIC)@.  Scratch registers need not have the same mode\n\
4449as the value being copied, and usually hold a different value than\n\
4450that being copied.  Special patterns in the md file are needed to\n\
4451describe how the copy is performed with the help of the scratch register;\n\
4452these patterns also describe the number, register class(es) and mode(s)\n\
4453of the scratch register(s).\n\
4454\n\
4455In some cases, both an intermediate and a scratch register are required.\n\
4456\n\
4457For input reloads, this target hook is called with nonzero @var{in_p},\n\
4458and @var{x} is an rtx that needs to be copied to a register of class\n\
4459@var{reload_class} in @var{reload_mode}.  For output reloads, this target\n\
4460hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4461needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4462\n\
4463If copying a register of @var{reload_class} from/to @var{x} requires\n\
4464an intermediate register, the hook @code{secondary_reload} should\n\
4465return the register class required for this intermediate register.\n\
4466If no intermediate register is required, it should return NO_REGS.\n\
4467If more than one intermediate register is required, describe the one\n\
4468that is closest in the copy chain to the reload register.\n\
4469\n\
4470If scratch registers are needed, you also have to describe how to\n\
4471perform the copy from/to the reload register to/from this\n\
4472closest intermediate register.  Or if no intermediate register is\n\
4473required, but still a scratch register is needed, describe the\n\
4474copy  from/to the reload register to/from the reload operand @var{x}.\n\
4475\n\
4476You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4477in the md file which performs the move.  Operands 0 and 1 are the output\n\
4478and input of this copy, respectively.  Operands from operand 2 onward are\n\
4479for scratch operands.  These scratch operands must have a mode, and a\n\
4480single-register-class\n\
4481@c [later: or memory]\n\
4482output constraint.\n\
4483\n\
4484When an intermediate register is used, the @code{secondary_reload}\n\
4485hook will be called again to determine how to copy the intermediate\n\
4486register to/from the reload operand @var{x}, so your hook must also\n\
4487have code to handle the register class of the intermediate operand.\n\
4488\n\
4489@c [For later: maybe we'll allow multi-alternative reload patterns -\n\
4490@c   the port maintainer could name a mov<mode> pattern that has clobbers -\n\
4491@c   and match the constraints of input and output to determine the required\n\
4492@c   alternative.  A restriction would be that constraints used to match\n\
4493@c   against reloads registers would have to be written as register class\n\
4494@c   constraints, or we need a new target macro / hook that tells us if an\n\
4495@c   arbitrary constraint can match an unknown register of a given class.\n\
4496@c   Such a macro / hook would also be useful in other places.]\n\
4497\n\
4498\n\
4499@var{x} might be a pseudo-register or a @code{subreg} of a\n\
4500pseudo-register, which could either be in a hard register or in memory.\n\
4501Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
4502in memory and the hard register number if it is in a register.\n\
4503\n\
4504Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
4505currently not supported.  For the time being, you will have to continue\n\
4506to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
4507\n\
4508@code{copy_cost} also uses this target hook to find out how values are\n\
4509copied.  If you want it to include some extra cost for the need to allocate\n\
4510(a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
4511Or if two dependent moves are supposed to have a lower cost than the sum\n\
4512of the individual moves due to expected fortuitous scheduling and/or special\n\
4513forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
4514 reg_class_t,
4515 (bool in_p, rtx x, reg_class_t reload_class, enum machine_mode reload_mode,
4516  secondary_reload_info *sri),
4517 default_secondary_reload)
4518
4519/* Given an rtx X being reloaded into a reg required to be in class CLASS,
4520   return the class of reg to actually use.  */
4521DEFHOOK
4522(preferred_reload_class,
4523 "A target hook that places additional restrictions on the register class\n\
4524to use when it is necessary to copy value @var{x} into a register in class\n\
4525@var{rclass}.  The value is a register class; perhaps @var{rclass}, or perhaps\n\
4526another, smaller class.\n\
4527\n\
4528The default version of this hook always returns value of @code{rclass} argument.\n\
4529\n\
4530Sometimes returning a more restrictive class makes better code.  For\n\
4531example, on the 68000, when @var{x} is an integer constant that is in range\n\
4532for a @samp{moveq} instruction, the value of this macro is always\n\
4533@code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
4534Requiring a data register guarantees that a @samp{moveq} will be used.\n\
4535\n\
4536One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
4537@var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
4538loaded into some register class.  By returning @code{NO_REGS} you can\n\
4539force @var{x} into a memory location.  For example, rs6000 can load\n\
4540immediate values into general-purpose registers, but does not have an\n\
4541instruction for loading an immediate value into a floating-point\n\
4542register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
4543@var{x} is a floating-point constant.  If the constant can't be loaded\n\
4544into any kind of register, code generation will be better if\n\
4545@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
4546of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
4547\n\
4548If an insn has pseudos in it after register allocation, reload will go\n\
4549through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
4550to find the best one.  Returning @code{NO_REGS}, in this case, makes\n\
4551reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
4552this feature to discourage usage of 387 registers when math is done in\n\
4553the SSE registers (and vice versa).",
4554 reg_class_t,
4555 (rtx x, reg_class_t rclass),
4556 default_preferred_reload_class)
4557
4558/* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
4559   input reloads.  */
4560DEFHOOK
4561(preferred_output_reload_class,
4562 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
4563input reloads.\n\
4564\n\
4565The default version of this hook always returns value of @code{rclass}\n\
4566argument.\n\
4567\n\
4568You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
4569reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
4570 reg_class_t,
4571 (rtx x, reg_class_t rclass),
4572 default_preferred_output_reload_class)
4573
4574DEFHOOK
4575(class_likely_spilled_p,
4576 "A target hook which returns @code{true} if pseudos that have been assigned\n\
4577to registers of class @var{rclass} would likely be spilled because\n\
4578registers of @var{rclass} are needed for spill registers.\n\
4579\n\
4580The default version of this target hook returns @code{true} if @var{rclass}\n\
4581has exactly one register and @code{false} otherwise.  On most machines, this\n\
4582default should be used.  For generally register-starved machines, such as\n\
4583i386, or machines with right register constraints, such as SH, this hook\n\
4584can be used to avoid excessive spilling.\n\
4585\n\
4586This hook is also used by some of the global intra-procedural code\n\
4587transformations to throtle code motion, to avoid increasing register\n\
4588pressure.",
4589 bool, (reg_class_t rclass),
4590 default_class_likely_spilled_p)
4591
4592/* Return the maximum number of consecutive registers
4593   needed to represent mode MODE in a register of class RCLASS.  */
4594DEFHOOK
4595(class_max_nregs,
4596 "A target hook returns the maximum number of consecutive registers\n\
4597of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
4598\n\
4599This is closely related to the macro @code{HARD_REGNO_NREGS}.  In fact,\n\
4600the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
4601@var{mode})} target hook should be the maximum value of\n\
4602@code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
4603values in the class @var{rclass}.\n\
4604\n\
4605This target hook helps control the handling of multiple-word values\n\
4606in the reload pass.\n\
4607\n\
4608The default version of this target hook returns the size of @var{mode}\n\
4609in words.",
4610 unsigned char, (reg_class_t rclass, enum machine_mode mode),
4611 default_class_max_nregs)
4612
4613DEFHOOK
4614(preferred_rename_class,
4615 "A target hook that places additional preference on the register\
4616 class to use when it is necessary to rename a register in class\
4617 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
4618 preferred register class is found or hook @code{preferred_rename_class}\
4619 is not implemented.\
4620 Sometimes returning a more restrictive class makes better code.  For\
4621 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
4622 smaller than instructions using @code{GENERIC_REGS}.  By returning\
4623 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
4624 be reduced.",
4625 reg_class_t, (reg_class_t rclass),
4626 default_preferred_rename_class)
4627
4628/* This target hook allows the backend to perform additional
4629   processing while initializing for variable expansion.  */
4630DEFHOOK
4631(expand_to_rtl_hook,
4632 "This hook is called just before expansion into rtl, allowing the target\n\
4633to perform additional initializations or analysis before the expansion.\n\
4634For example, the rs6000 port uses it to allocate a scratch stack slot\n\
4635for use in copying SDmode values between memory and floating point\n\
4636registers whenever the function being expanded has any SDmode\n\
4637usage.",
4638 void, (void),
4639 hook_void_void)
4640
4641/* This target hook allows the backend to perform additional
4642   instantiations on rtx that are not actually in insns yet,
4643   but will be later.  */
4644DEFHOOK
4645(instantiate_decls,
4646 "This hook allows the backend to perform additional instantiations on rtl\n\
4647that are not actually in any insns yet, but will be later.",
4648 void, (void),
4649 hook_void_void)
4650
4651/* Return true if is OK to use a hard register REGNO as scratch register
4652   in peephole2.  */
4653DEFHOOK
4654(hard_regno_scratch_ok,
4655 "This target hook should return @code{true} if it is OK to use a hard register\n\
4656@var{regno} as scratch reg in peephole2.\n\
4657\n\
4658One common use of this macro is to prevent using of a register that\n\
4659is not saved by a prologue in an interrupt handler.\n\
4660\n\
4661The default version of this hook always returns @code{true}.",
4662 bool, (unsigned int regno),
4663 default_hard_regno_scratch_ok)
4664
4665/* Return the smallest number of different values for which it is best to
4666   use a jump-table instead of a tree of conditional branches.  */
4667DEFHOOK
4668(case_values_threshold,
4669 "This function return the smallest number of different values for which it\n\
4670is best to use a jump-table instead of a tree of conditional branches.\n\
4671The default is four for machines with a @code{casesi} instruction and\n\
4672five otherwise.  This is best for most machines.",
4673 unsigned int, (void),
4674 default_case_values_threshold)
4675
4676/* Retutn true if a function must have and use a frame pointer.  */
4677DEFHOOK
4678(frame_pointer_required,
4679 "This target hook should return @code{true} if a function must have and use\n\
4680a frame pointer.  This target hook is called in the reload pass.  If its return\n\
4681value is @code{true} the function will have a frame pointer.\n\
4682\n\
4683This target hook can in principle examine the current function and decide\n\
4684according to the facts, but on most machines the constant @code{false} or the\n\
4685constant @code{true} suffices.  Use @code{false} when the machine allows code\n\
4686to be generated with no frame pointer, and doing so saves some time or space.\n\
4687Use @code{true} when there is no possible advantage to avoiding a frame\n\
4688pointer.\n\
4689\n\
4690In certain cases, the compiler does not know how to produce valid code\n\
4691without a frame pointer.  The compiler recognizes those cases and\n\
4692automatically gives the function a frame pointer regardless of what\n\
4693@code{TARGET_FRAME_POINTER_REQUIRED} returns.  You don't need to worry about\n\
4694them.\n\
4695\n\
4696In a function that does not require a frame pointer, the frame pointer\n\
4697register can be allocated for ordinary usage, unless you mark it as a\n\
4698fixed register.  See @code{FIXED_REGISTERS} for more information.\n\
4699\n\
4700Default return value is @code{false}.",
4701 bool, (void),
4702 hook_bool_void_false)
4703
4704/* Returns true if the compiler is allowed to try to replace register number
4705   from-reg with register number to-reg.  */
4706DEFHOOK
4707(can_eliminate,
4708 "This target hook should returns @code{true} if the compiler is allowed to\n\
4709try to replace register number @var{from_reg} with register number\n\
4710@var{to_reg}.  This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
4711is defined, and will usually be @code{true}, since most of the cases\n\
4712preventing register elimination are things that the compiler already\n\
4713knows about.\n\
4714\n\
4715Default return value is @code{true}.",
4716 bool, (const int from_reg, const int to_reg),
4717 hook_bool_const_int_const_int_true)
4718
4719/* Modify any or all of fixed_regs, call_used_regs, global_regs,
4720   reg_names, and reg_class_contents to account of the vagaries of the
4721   target.  */
4722DEFHOOK
4723(conditional_register_usage,
4724 "This hook may conditionally modify five variables\n\
4725@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
4726@code{reg_names}, and @code{reg_class_contents}, to take into account\n\
4727any dependence of these register sets on target flags.  The first three\n\
4728of these are of type @code{char []} (interpreted as Boolean vectors).\n\
4729@code{global_regs} is a @code{const char *[]}, and\n\
4730@code{reg_class_contents} is a @code{HARD_REG_SET}.  Before the macro is\n\
4731called, @code{fixed_regs}, @code{call_used_regs},\n\
4732@code{reg_class_contents}, and @code{reg_names} have been initialized\n\
4733from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
4734@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
4735@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
4736@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
4737command options have been applied.\n\
4738\n\
4739@cindex disabling certain registers\n\
4740@cindex controlling register usage\n\
4741If the usage of an entire class of registers depends on the target\n\
4742flags, you may indicate this to GCC by using this macro to modify\n\
4743@code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
4744registers in the classes which should not be used by GCC@.  Also define\n\
4745the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT}\n\
4746to return @code{NO_REGS} if it\n\
4747is called with a letter for a class that shouldn't be used.\n\
4748\n\
4749(However, if this class is not included in @code{GENERAL_REGS} and all\n\
4750of the insn patterns whose constraints permit this class are\n\
4751controlled by target switches, then GCC will automatically avoid using\n\
4752these registers when the target switches are opposed to them.)",
4753 void, (void),
4754 hook_void_void)
4755
4756/* Functions specific to the C family of frontends.  */
4757#undef HOOK_PREFIX
4758#define HOOK_PREFIX "TARGET_C_"
4759HOOK_VECTOR (TARGET_C, c)
4760
4761/* ??? Documenting this hook requires a GFDL license grant.  */
4762DEFHOOK_UNDOC
4763(mode_for_suffix,
4764"Return machine mode for non-standard constant literal suffix @var{c},\
4765 or VOIDmode if non-standard suffixes are unsupported.",
4766 enum machine_mode, (char c),
4767 default_mode_for_suffix)
4768
4769HOOK_VECTOR_END (c)
4770
4771/* Functions specific to the C++ frontend.  */
4772#undef HOOK_PREFIX
4773#define HOOK_PREFIX "TARGET_CXX_"
4774HOOK_VECTOR (TARGET_CXX, cxx)
4775
4776/* Return the integer type used for guard variables.  */
4777DEFHOOK
4778(guard_type,
4779 "Define this hook to override the integer type used for guard variables.\n\
4780These are used to implement one-time construction of static objects.  The\n\
4781default is long_long_integer_type_node.",
4782 tree, (void),
4783 default_cxx_guard_type)
4784
4785/* Return true if only the low bit of the guard should be tested.  */
4786DEFHOOK
4787(guard_mask_bit,
4788 "This hook determines how guard variables are used.  It should return\n\
4789@code{false} (the default) if the first byte should be used.  A return value of\n\
4790@code{true} indicates that only the least significant bit should be used.",
4791 bool, (void),
4792 hook_bool_void_false)
4793
4794/* Returns the size of the array cookie for an array of type.  */
4795DEFHOOK
4796(get_cookie_size,
4797 "This hook returns the size of the cookie to use when allocating an array\n\
4798whose elements have the indicated @var{type}.  Assumes that it is already\n\
4799known that a cookie is needed.  The default is\n\
4800@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
4801IA64/Generic C++ ABI@.",
4802 tree, (tree type),
4803 default_cxx_get_cookie_size)
4804
4805/* Returns true if the element size should be stored in the array cookie.  */
4806DEFHOOK
4807(cookie_has_size,
4808 "This hook should return @code{true} if the element size should be stored in\n\
4809array cookies.  The default is to return @code{false}.",
4810 bool, (void),
4811 hook_bool_void_false)
4812
4813/* Allows backends to perform additional processing when
4814   deciding if a class should be exported or imported.  */
4815DEFHOOK
4816(import_export_class,
4817 "If defined by a backend this hook allows the decision made to export\n\
4818class @var{type} to be overruled.  Upon entry @var{import_export}\n\
4819will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
4820to be imported and 0 otherwise.  This function should return the\n\
4821modified value and perform any other actions necessary to support the\n\
4822backend's targeted operating system.",
4823 int, (tree type, int import_export), NULL)
4824
4825/* Returns true if constructors and destructors return "this".  */
4826DEFHOOK
4827(cdtor_returns_this,
4828 "This hook should return @code{true} if constructors and destructors return\n\
4829the address of the object created/destroyed.  The default is to return\n\
4830@code{false}.",
4831 bool, (void),
4832 hook_bool_void_false)
4833
4834/* Returns true if the key method for a class can be an inline
4835   function, so long as it is not declared inline in the class
4836   itself.  Returning true is the behavior required by the Itanium C++ ABI.  */
4837DEFHOOK
4838(key_method_may_be_inline,
4839 "This hook returns true if the key method for a class (i.e., the method\n\
4840which, if defined in the current translation unit, causes the virtual\n\
4841table to be emitted) may be an inline function.  Under the standard\n\
4842Itanium C++ ABI the key method may be an inline function so long as\n\
4843the function is not declared inline in the class definition.  Under\n\
4844some variants of the ABI, an inline function can never be the key\n\
4845method.  The default is to return @code{true}.",
4846 bool, (void),
4847 hook_bool_void_true)
4848
4849DEFHOOK
4850(determine_class_data_visibility,
4851"@var{decl} is a virtual table, virtual table table, typeinfo object,\
4852 or other similar implicit class data object that will be emitted with\
4853 external linkage in this translation unit.  No ELF visibility has been\
4854 explicitly specified.  If the target needs to specify a visibility\
4855 other than that of the containing class, use this hook to set\
4856 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
4857 void, (tree decl),
4858 hook_void_tree)
4859
4860/* Returns true (the default) if virtual tables and other
4861   similar implicit class data objects are always COMDAT if they
4862   have external linkage.  If this hook returns false, then
4863   class data for classes whose virtual table will be emitted in
4864   only one translation unit will not be COMDAT.  */
4865DEFHOOK
4866(class_data_always_comdat,
4867 "This hook returns true (the default) if virtual tables and other\n\
4868similar implicit class data objects are always COMDAT if they have\n\
4869external linkage.  If this hook returns false, then class data for\n\
4870classes whose virtual table will be emitted in only one translation\n\
4871unit will not be COMDAT.",
4872 bool, (void),
4873 hook_bool_void_true)
4874
4875/* Returns true (the default) if the RTTI for the basic types,
4876   which is always defined in the C++ runtime, should be COMDAT;
4877   false if it should not be COMDAT.  */
4878DEFHOOK
4879(library_rtti_comdat,
4880 "This hook returns true (the default) if the RTTI information for\n\
4881the basic types which is defined in the C++ runtime should always\n\
4882be COMDAT, false if it should not be COMDAT.",
4883 bool, (void),
4884 hook_bool_void_true)
4885
4886/* Returns true if __aeabi_atexit should be used to register static
4887   destructors.  */
4888DEFHOOK
4889(use_aeabi_atexit,
4890 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
4891should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
4892is in effect.  The default is to return false to use @code{__cxa_atexit}.",
4893 bool, (void),
4894 hook_bool_void_false)
4895
4896/* Returns true if target may use atexit in the same manner as
4897   __cxa_atexit  to register static destructors.  */
4898DEFHOOK
4899(use_atexit_for_cxa_atexit,
4900 "This hook returns true if the target @code{atexit} function can be used\n\
4901in the same manner as @code{__cxa_atexit} to register C++ static\n\
4902destructors. This requires that @code{atexit}-registered functions in\n\
4903shared libraries are run in the correct order when the libraries are\n\
4904unloaded. The default is to return false.",
4905 bool, (void),
4906 hook_bool_void_false)
4907
4908DEFHOOK
4909(adjust_class_at_definition,
4910"@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
4911 been defined.  Use this hook to make adjustments to the class (eg, tweak\
4912 visibility or perform any other required target modifications).",
4913 void, (tree type),
4914 hook_void_tree)
4915
4916DEFHOOK
4917(decl_mangling_context,
4918 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
4919 tree, (const_tree decl),
4920 hook_tree_const_tree_null)
4921
4922HOOK_VECTOR_END (cxx)
4923
4924/* Functions and data for emulated TLS support.  */
4925#undef HOOK_PREFIX
4926#define HOOK_PREFIX "TARGET_EMUTLS_"
4927HOOK_VECTOR (TARGET_EMUTLS, emutls)
4928
4929/* Name of the address and common functions.  */
4930DEFHOOKPOD
4931(get_address,
4932 "Contains the name of the helper function that uses a TLS control\n\
4933object to locate a TLS instance.  The default causes libgcc's\n\
4934emulated TLS helper function to be used.",
4935 const char *, "__builtin___emutls_get_address")
4936
4937DEFHOOKPOD
4938(register_common,
4939 "Contains the name of the helper function that should be used at\n\
4940program startup to register TLS objects that are implicitly\n\
4941initialized to zero.  If this is @code{NULL}, all TLS objects will\n\
4942have explicit initializers.  The default causes libgcc's emulated TLS\n\
4943registration function to be used.",
4944 const char *, "__builtin___emutls_register_common")
4945
4946/* Prefixes for proxy variable and template.  */
4947DEFHOOKPOD
4948(var_section,
4949 "Contains the name of the section in which TLS control variables should\n\
4950be placed.  The default of @code{NULL} allows these to be placed in\n\
4951any section.",
4952 const char *, NULL)
4953
4954DEFHOOKPOD
4955(tmpl_section,
4956 "Contains the name of the section in which TLS initializers should be\n\
4957placed.  The default of @code{NULL} allows these to be placed in any\n\
4958section.",
4959 const char *, NULL)
4960
4961/* Prefixes for proxy variable and template.  */
4962DEFHOOKPOD
4963(var_prefix,
4964 "Contains the prefix to be prepended to TLS control variable names.\n\
4965The default of @code{NULL} uses a target-specific prefix.",
4966 const char *, NULL)
4967
4968DEFHOOKPOD
4969(tmpl_prefix,
4970 "Contains the prefix to be prepended to TLS initializer objects.  The\n\
4971default of @code{NULL} uses a target-specific prefix.",
4972 const char *, NULL)
4973
4974/* Function to generate field definitions of the proxy variable.  */
4975DEFHOOK
4976(var_fields,
4977 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
4978object type.  @var{type} is the RECORD_TYPE the fields are for and\n\
4979@var{name} should be filled with the structure tag, if the default of\n\
4980@code{__emutls_object} is unsuitable.  The default creates a type suitable\n\
4981for libgcc's emulated TLS function.",
4982 tree, (tree type, tree *name),
4983 default_emutls_var_fields)
4984
4985/* Function to initialize a proxy variable.  */
4986DEFHOOK
4987(var_init,
4988 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
4989TLS control object.  @var{var} is the TLS control object, @var{decl}\n\
4990is the TLS object and @var{tmpl_addr} is the address of the\n\
4991initializer.  The default initializes libgcc's emulated TLS control object.",
4992 tree, (tree var, tree decl, tree tmpl_addr),
4993 default_emutls_var_init)
4994
4995/* Whether we are allowed to alter the usual alignment of the
4996   proxy variable.  */
4997DEFHOOKPOD
4998(var_align_fixed,
4999 "Specifies whether the alignment of TLS control variable objects is\n\
5000fixed and should not be increased as some backends may do to optimize\n\
5001single objects.  The default is false.",
5002 bool, false)
5003
5004/* Whether we can emit debug information for TLS vars.  */
5005DEFHOOKPOD
5006(debug_form_tls_address,
5007 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5008may be used to describe emulated TLS control objects.",
5009 bool, false)
5010
5011HOOK_VECTOR_END (emutls)
5012
5013#undef HOOK_PREFIX
5014#define HOOK_PREFIX "TARGET_OPTION_"
5015HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5016
5017/* Function to validate the attribute((target(...))) strings.  If
5018   the option is validated, the hook should also fill in
5019   DECL_FUNCTION_SPECIFIC_TARGET in the function decl node.  */
5020DEFHOOK
5021(valid_attribute_p,
5022 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5023allows setting target-specific options on individual functions.\n\
5024These function-specific options may differ\n\
5025from the options specified on the command line.  The hook should return\n\
5026@code{true} if the options are valid.\n\
5027\n\
5028The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5029the function declaration to hold a pointer to a target-specific\n\
5030@code{struct cl_target_option} structure.",
5031 bool, (tree fndecl, tree name, tree args, int flags),
5032 default_target_option_valid_attribute_p)
5033
5034/* Function to save any extra target state in the target options structure.  */
5035DEFHOOK
5036(save,
5037 "This hook is called to save any additional target-specific information\n\
5038in the @code{struct cl_target_option} structure for function-specific\n\
5039options from the @code{struct gcc_options} structure.\n\
5040@xref{Option file format}.",
5041 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5042
5043/* Function to restore any extra target state from the target options
5044   structure.  */
5045DEFHOOK
5046(restore,
5047 "This hook is called to restore any additional target-specific\n\
5048information in the @code{struct cl_target_option} structure for\n\
5049function-specific options to the @code{struct gcc_options} structure.",
5050 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5051
5052/* Function to print any extra target state from the target options
5053   structure.  */
5054DEFHOOK
5055(print,
5056 "This hook is called to print any additional target-specific\n\
5057information in the @code{struct cl_target_option} structure for\n\
5058function-specific options.",
5059 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5060
5061/* Function to parse arguments to be validated for #pragma target, and to
5062   change the state if the options are valid.  If the first argument is
5063   NULL, the second argument specifies the default options to use.  Return
5064   true if the options are valid, and set the current state.  */
5065DEFHOOK
5066(pragma_parse,
5067 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5068sets the target-specific options for functions that occur later in the\n\
5069input stream.  The options accepted should be the same as those handled by the\n\
5070@code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5071 bool, (tree args, tree pop_target),
5072 default_target_option_pragma_parse)
5073
5074/* Do option overrides for the target.  */
5075DEFHOOK
5076(override,
5077 "Sometimes certain combinations of command options do not make sense on\n\
5078a particular target machine.  You can override the hook\n\
5079@code{TARGET_OPTION_OVERRIDE} to take account of this.  This hooks is called\n\
5080once just after all the command options have been parsed.\n\
5081\n\
5082Don't use this hook to turn on various extra optimizations for\n\
5083@option{-O}.  That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5084\n\
5085If you need to do something whenever the optimization level is\n\
5086changed via the optimize attribute or pragma, see\n\
5087@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5088 void, (void),
5089 hook_void_void)
5090
5091/* This function returns true if DECL1 and DECL2 are versions of the same
5092   function.  DECL1 and DECL2 are function versions if and only if they
5093   have the same function signature and different target specific attributes,
5094   that is, they are compiled for different target machines.  */
5095DEFHOOK
5096(function_versions,
5097 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5098versions of the same function.  @var{DECL1} and @var{DECL2} are function\n\
5099versions if and only if they have the same function signature and\n\
5100different target specific attributes, that is, they are compiled for\n\
5101different target machines.",
5102 bool, (tree decl1, tree decl2),
5103 hook_bool_tree_tree_false)
5104
5105/* Function to determine if one function can inline another function.  */
5106#undef HOOK_PREFIX
5107#define HOOK_PREFIX "TARGET_"
5108DEFHOOK
5109(can_inline_p,
5110 "This target hook returns @code{false} if the @var{caller} function\n\
5111cannot inline @var{callee}, based on target specific information.  By\n\
5112default, inlining is not allowed if the callee function has function\n\
5113specific target options and the caller does not use the same options.",
5114 bool, (tree caller, tree callee),
5115 default_target_can_inline_p)
5116
5117HOOK_VECTOR_END (target_option)
5118
5119/* For targets that need to mark extra registers as live on entry to
5120   the function, they should define this target hook and set their
5121   bits in the bitmap passed in. */
5122DEFHOOK
5123(extra_live_on_entry,
5124 "Add any hard registers to @var{regs} that are live on entry to the\n\
5125function.  This hook only needs to be defined to provide registers that\n\
5126cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5127registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5128TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5129FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5130 void, (bitmap regs),
5131 hook_void_bitmap)
5132
5133/* Fill in additional registers set up by prologue into a regset.  */
5134DEFHOOK
5135(set_up_by_prologue,
5136 "This hook should add additional registers that are computed by the prologue\
5137 to the hard regset for shrink-wrapping optimization purposes.",
5138 void, (struct hard_reg_set_container *),
5139 NULL)
5140
5141/* For targets that have attributes that can affect whether a
5142   function's return statements need checking.  For instance a 'naked'
5143   function attribute.  */
5144DEFHOOK
5145(warn_func_return,
5146 "True if a function's return statements should be checked for matching the function's return type.  This includes checking for falling off the end of a non-void function.  Return false if no such check should be made.",
5147 bool, (tree),
5148 hook_bool_tree_true)
5149
5150/* Determine the type of unwind info to emit for debugging.  */
5151DEFHOOK
5152(debug_unwind_info,
5153 "This hook defines the mechanism that will be used for describing frame\n\
5154unwind information to the debugger.  Normally the hook will return\n\
5155@code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5156return @code{UI_NONE} otherwise.\n\
5157\n\
5158A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5159is disabled in order to always output DWARF 2 frame information.\n\
5160\n\
5161A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5162This will suppress generation of the normal debug frame unwind information.",
5163 enum unwind_info_type, (void),
5164 default_debug_unwind_info)
5165
5166/* The code parameter should be of type enum rtx_code but this is not
5167   defined at this time.  */
5168DEFHOOK
5169(canonicalize_comparison,
5170 "On some machines not all possible comparisons are defined, but you can\n\
5171convert an invalid comparison into a valid one.  For example, the Alpha\n\
5172does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5173comparison instead and swap the order of the operands.\n\
5174\n\
5175On such machines, implement this hook to do any required conversions.\n\
5176@var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5177are the left and right operands of the comparison, respectively.  If\n\
5178@var{op0_preserve_value} is @code{true} the implementation is not\n\
5179allowed to change the value of @var{op0} since the value might be used\n\
5180in RTXs which aren't comparisons.  E.g. the implementation is not\n\
5181allowed to swap operands in that case.\n\
5182\n\
5183GCC will not assume that the comparison resulting from this macro is\n\
5184valid but will see if the resulting insn matches a pattern in the\n\
5185@file{md} file.\n\
5186\n\
5187You need not to implement this hook if it would never change the\n\
5188comparison code or operands.",
5189 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5190 default_canonicalize_comparison)
5191
5192DEFHOOKPOD
5193(atomic_test_and_set_trueval,
5194 "This value should be set if the result written by\
5195 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5196 @code{bool} @code{true}.",
5197 unsigned char, 1)
5198
5199/* Return an unsigned int representing the alignment (in bits) of the atomic
5200   type which maps to machine MODE.  This allows alignment to be overridden
5201   as needed.  */
5202DEFHOOK
5203(atomic_align_for_mode,
5204"If defined, this function returns an appropriate alignment in bits for an\
5205 atomic object of machine_mode @var{mode}.  If 0 is returned then the\
5206 default alignment for the specified mode is used. ",
5207 unsigned int, (enum machine_mode mode),
5208 hook_uint_mode_0)
5209
5210DEFHOOK
5211(atomic_assign_expand_fenv,
5212"ISO C11 requires atomic compound assignments that may raise floating-point\
5213 exceptions to raise exceptions corresponding to the arithmetic operation\
5214 whose result was successfully stored in a compare-and-exchange sequence. \
5215 This requires code equivalent to calls to @code{feholdexcept},\
5216 @code{feclearexcept} and @code{feupdateenv} to be generated at\
5217 appropriate points in the compare-and-exchange sequence.  This hook should\
5218 set @code{*@var{hold}} to an expression equivalent to the call to\
5219 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
5220 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
5221 equivalent to the call to @code{feupdateenv}.  The three expressions are\
5222 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
5223 if no code is required in a particular place.  The default implementation\
5224 leaves all three expressions as @code{NULL_TREE}.  The\
5225 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
5226 as part of the code generated in @code{*@var{update}}.",
5227 void, (tree *hold, tree *clear, tree *update),
5228 default_atomic_assign_expand_fenv)
5229
5230/* Leave the boolean fields at the end.  */
5231
5232/* True if we can create zeroed data by switching to a BSS section
5233   and then using ASM_OUTPUT_SKIP to allocate the space.  */
5234DEFHOOKPOD
5235(have_switchable_bss_sections,
5236 "This flag is true if we can create zeroed data by switching to a BSS\n\
5237section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5238This is true on most ELF targets.",
5239 bool, false)
5240
5241/* True if "native" constructors and destructors are supported,
5242   false if we're using collect2 for the job.  */
5243DEFHOOKPOD
5244(have_ctors_dtors,
5245 "This value is true if the target supports some ``native'' method of\n\
5246collecting constructors and destructors to be run at startup and exit.\n\
5247It is false if we must use @command{collect2}.",
5248 bool, false)
5249
5250/* True if thread-local storage is supported.  */
5251DEFHOOKPOD
5252(have_tls,
5253 "Contains the value true if the target supports thread-local storage.\n\
5254The default value is false.",
5255 bool, false)
5256
5257/* True if a small readonly data section is supported.  */
5258DEFHOOKPOD
5259(have_srodata_section,
5260 "Contains the value true if the target places read-only\n\
5261``small data'' into a separate section.  The default value is false.",
5262 bool, false)
5263
5264/* True if EH frame info sections should be zero-terminated.  */
5265DEFHOOKPOD
5266(terminate_dw2_eh_frame_info,
5267 "Contains the value true if the target should add a zero word onto the\n\
5268end of a Dwarf-2 frame info section when used for exception handling.\n\
5269Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5270true otherwise.",
5271 bool, true)
5272
5273/* True if #NO_APP should be emitted at the beginning of assembly output.  */
5274DEFHOOKPOD
5275(asm_file_start_app_off,
5276 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5277printed as the very first line in the assembly file, unless\n\
5278@option{-fverbose-asm} is in effect.  (If that macro has been defined\n\
5279to the empty string, this variable has no effect.)  With the normal\n\
5280definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5281assembler that it need not bother stripping comments or extra\n\
5282whitespace from its input.  This allows it to work a bit faster.\n\
5283\n\
5284The default is false.  You should not set it to true unless you have\n\
5285verified that your port does not generate any extra whitespace or\n\
5286comments that will cause GAS to issue errors in NO_APP mode.",
5287 bool, false)
5288
5289/* True if output_file_directive should be called for main_input_filename
5290   at the beginning of assembly output.  */
5291DEFHOOKPOD
5292(asm_file_start_file_directive,
5293 "If this flag is true, @code{output_file_directive} will be called\n\
5294for the primary source file, immediately after printing\n\
5295@code{ASM_APP_OFF} (if that is enabled).  Most ELF assemblers expect\n\
5296this to be done.  The default is false.",
5297 bool, false)
5298
5299/* True if the target is allowed to reorder memory accesses unless
5300   synchronization is explicitly requested.  */
5301DEFHOOKPOD
5302(relaxed_ordering,
5303 "If set to @code{true}, means that the target's memory model does not\n\
5304guarantee that loads which do not depend on one another will access\n\
5305main memory in the order of the instruction stream; if ordering is\n\
5306important, an explicit memory barrier must be used.  This is true of\n\
5307many recent processors which implement a policy of ``relaxed,''\n\
5308``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,\n\
5309and ia64.  The default is @code{false}.",
5310 bool, false)
5311
5312/* Returns true if we should generate exception tables for use with the
5313   ARM EABI.  The effects the encoding of function exception specifications.  */
5314DEFHOOKPOD
5315(arm_eabi_unwinder,
5316 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5317based unwinding library, and @code{false} on other targets.  This effects\n\
5318the format of unwinding tables, and how the unwinder in entered after\n\
5319running a cleanup.  The default is @code{false}.",
5320 bool, false)
5321
5322DEFHOOKPOD
5323(want_debug_pub_sections,
5324 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5325 should be emitted.  These sections are not used on most platforms, and\
5326 in particular GDB does not use them.",
5327 bool, false)
5328
5329DEFHOOKPOD
5330(force_at_comp_dir,
5331 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5332 compilation unit.  This attribute is required for the darwin linker \
5333 to emit debug information.",
5334 bool, false)
5335
5336DEFHOOKPOD
5337(delay_sched2, "True if sched2 is not to be run at its normal place.  \
5338This usually means it will be run as part of machine-specific reorg.",
5339bool, false)
5340
5341DEFHOOKPOD
5342(delay_vartrack, "True if vartrack is not to be run at its normal place.  \
5343This usually means it will be run as part of machine-specific reorg.",
5344bool, false)
5345
5346/* Leave the boolean fields at the end.  */
5347
5348/* Close the 'struct gcc_target' definition.  */
5349HOOK_VECTOR_END (C90_EMPTY_HACK)
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