1 /* Target hook definitions.
2 Copyright (C) 2001-2014 Free Software Foundation, Inc.
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
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.
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/>.
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! */
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"
27 #define HOOK_TYPE "Target Hook"
29 HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
31 /* Functions that output assembler for the target. */
32 #define HOOK_PREFIX "TARGET_ASM_"
33 HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
35 /* Opening and closing parentheses for asm expression grouping. */
38 "These target hooks are C string constants, describing the syntax in the\n\
39 assembler for grouping arithmetic expressions. If not overridden, they\n\
40 default to normal parentheses, which is correct for most assemblers.",
42 DEFHOOKPODX (close_paren, const char *, ")")
44 /* Assembler instructions for creating various kinds of integer object. */
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\
55 These hooks specify assembly directives for creating certain kinds\n\
56 of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
57 byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
58 aligned two-byte object, and so on. Any of the hooks may be\n\
59 @code{NULL}, indicating that no suitable directive is available.\n\
61 The compiler will print these strings at the start of a new line,\n\
62 followed immediately by the object's initial value. In most cases,\n\
63 the string should contain a tab, a pseudo-op, and then another tab.",
64 const char *, "\t.byte\t")
65 DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
66 DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
68 /* The maximum number of bytes to skip when applying
69 LABEL_ALIGN_AFTER_BARRIER. */
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.",
76 default_label_align_after_barrier_max_skip)
78 /* The maximum number of bytes to skip when applying
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\
86 default_loop_align_max_skip)
88 /* The maximum number of bytes to skip when applying
91 (label_align_max_skip,
92 "The maximum number of bytes to skip when applying @code{LABEL_ALIGN}\n\
93 to @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}\n\
96 default_label_align_max_skip)
98 /* The maximum number of bytes to skip when applying
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.",
106 default_jump_align_max_skip)
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. */
115 "The @code{assemble_integer} function uses this hook to output an\n\
116 integer object. @var{x} is the object's value, @var{size} is its size\n\
117 in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
118 function should return @code{true} if it was able to output the\n\
119 object. If it returns false, @code{assemble_integer} will try to\n\
120 split the object into smaller parts.\n\
122 The default implementation of this hook will use the\n\
123 @code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
124 when the relevant string is @code{NULL}.",
125 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
130 /* Output code that will globalize a 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\
135 that is, available for reference from other files.\n\
137 The 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)
142 /* Output code that will globalize a declaration. */
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\
147 global; that is, available for reference from other files.\n\
149 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
150 void, (FILE *stream, tree decl), default_globalize_decl_name)
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. */
159 "This target hook emits a label at the beginning of each FDE@. It\n\
160 should be defined on targets where FDEs need special labels, and it\n\
161 should write the appropriate label, for the FDE associated with the\n\
162 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
163 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
164 exception table. The fourth argument, @var{empty}, is a boolean:\n\
165 true if this is a placeholder label for an omitted FDE@.\n\
167 The 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)
171 /* Output code that will emit a label to divide up the exception table. */
173 (emit_except_table_label,
174 "This target hook emits a label at the beginning of the exception table.\n\
175 It should be defined on targets where it is desirable for the table\n\
176 to be broken up according to function.\n\
178 The default is that no label is emitted.",
179 void, (FILE *stream),
180 default_emit_except_table_label)
182 /* Emit a directive for setting the personality for the function. */
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),
191 /* Emit any directives required to unwind this instruction. */
194 "This target hook emits assembly directives required to unwind the\n\
195 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
196 returns @code{UI_TARGET}.",
197 void, (FILE *stream, rtx insn),
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.",
207 /* Generate an internal label.
208 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
210 (generate_internal_label,
212 void, (char *buf, const char *prefix, unsigned long labelno),
213 default_generate_internal_label)
215 /* Output an internal label. */
218 "A function to output to the stdio stream @var{stream} a label whose\n\
219 name is made from the string @var{prefix} and the number @var{labelno}.\n\
221 It is absolutely essential that these labels be distinct from the labels\n\
222 used for user-level functions and variables. Otherwise, certain programs\n\
223 will have name conflicts with internal labels.\n\
225 It is desirable to exclude internal labels from the symbol table of the\n\
226 object file. Most assemblers have a naming convention for labels that\n\
227 should be excluded; on many systems, the letter @samp{L} at the\n\
228 beginning of a label has this effect. You should find out what\n\
229 convention your system uses, and follow it.\n\
231 The 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)
235 /* Output label for the constant. */
237 (declare_constant_name,
238 "A target hook to output to the stdio stream @var{file} any text necessary\n\
239 for declaring the name @var{name} of a constant which is being defined. This\n\
240 target 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\
242 and @var{size} is the size of the constant in bytes. The @var{name}\n\
243 will be an internal label.\n\
245 The default version of this target hook, define the @var{name} in the\n\
246 usual manner as a label (by means of @code{assemble_label}).\n\
248 You 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)
252 /* Emit a ttype table reference to a typeinfo object. */
255 "This hook is used to output a reference from a frame unwinding table to\n\
256 the type_info object identified by @var{sym}. It should return @code{true}\n\
257 if the reference was output. Returning @code{false} will cause the\n\
258 reference to be output using the normal Dwarf2 routines.",
262 /* Emit an assembler directive to set visibility for the symbol
263 associated with the tree decl. */
265 (assemble_visibility,
266 "This target hook is a function to output to @var{asm_out_file} some\n\
267 commands that will make the symbol(s) associated with @var{decl} have\n\
268 hidden, protected or internal visibility as specified by @var{visibility}.",
269 void, (tree decl, int visibility),
270 default_assemble_visibility)
272 /* Output the assembler code for entry to a function. */
275 "If defined, a function that outputs the assembler code for entry to a\n\
276 function. The prologue is responsible for setting up the stack frame,\n\
277 initializing the frame pointer register, saving registers that must be\n\
278 saved, and allocating @var{size} additional bytes of storage for the\n\
279 local variables. @var{size} is an integer. @var{file} is a stdio\n\
280 stream to which the assembler code should be output.\n\
282 The label for the beginning of the function need not be output by this\n\
283 macro. That has already been done when the macro is run.\n\
285 @findex regs_ever_live\n\
286 To 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\
289 prologue should save register @var{r}, provided it is not one of the\n\
290 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
291 @code{regs_ever_live}.)\n\
293 On machines that have ``register windows'', the function entry code does\n\
294 not save on the stack the registers that are in the windows, even if\n\
295 they are supposed to be preserved by function calls; instead it takes\n\
296 appropriate steps to ``push'' the register stack, if any non-call-used\n\
297 registers are used in the function.\n\
299 @findex frame_pointer_needed\n\
300 On machines where functions may or may not have frame-pointers, the\n\
301 function entry code must vary accordingly; it must set up the frame\n\
302 pointer if one is wanted, and not otherwise. To determine whether a\n\
303 frame 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\
305 time in a function that needs a frame pointer. @xref{Elimination}.\n\
307 The function entry code is responsible for allocating any stack space\n\
308 required for the function. This stack space consists of the regions\n\
309 listed below. In most cases, these regions are allocated in the\n\
310 order listed, with the last listed region closest to the top of the\n\
311 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
312 the highest address if it is not defined). You can use a different order\n\
313 for a machine if doing so is more convenient or required for\n\
314 compatibility reasons. Except in cases where required by standard\n\
315 or by a debugger, there is no reason why the stack layout used by GCC\n\
316 need agree with that used by other compilers for a machine.",
317 void, (FILE *file, HOST_WIDE_INT size),
318 default_function_pro_epilogue)
320 /* Output the assembler code for end of prologue. */
322 (function_end_prologue,
323 "If defined, a function that outputs assembler code at the end of a\n\
324 prologue. This should be used when the function prologue is being\n\
325 emitted as RTL, and you have some extra assembler that needs to be\n\
326 emitted. @xref{prologue instruction pattern}.",
330 /* Output the assembler code for start of epilogue. */
332 (function_begin_epilogue,
333 "If defined, a function that outputs assembler code at the start of an\n\
334 epilogue. This should be used when the function epilogue is being\n\
335 emitted as RTL, and you have some extra assembler that needs to be\n\
336 emitted. @xref{epilogue instruction pattern}.",
340 /* Output the assembler code for function exit. */
343 "If defined, a function that outputs the assembler code for exit from a\n\
344 function. The epilogue is responsible for restoring the saved\n\
345 registers and stack pointer to their values when the function was\n\
346 called, and returning control to the caller. This macro takes the\n\
347 same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
348 registers to restore are determined from @code{regs_ever_live} and\n\
349 @code{CALL_USED_REGISTERS} in the same way.\n\
351 On some machines, there is a single instruction that does all the work\n\
352 of returning from the function. On these machines, give that\n\
353 instruction the name @samp{return} and do not define the macro\n\
354 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
356 Do 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\
358 switches to control whether return instructions or epilogues are used,\n\
359 define a @samp{return} pattern with a validity condition that tests the\n\
360 target switches appropriately. If the @samp{return} pattern's validity\n\
361 condition is false, epilogues will be used.\n\
363 On machines where functions may or may not have frame-pointers, the\n\
364 function exit code must vary accordingly. Sometimes the code for these\n\
365 two cases is completely different. To determine whether a frame pointer\n\
366 is wanted, the macro can refer to the variable\n\
367 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
368 a function that needs a frame pointer.\n\
370 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
371 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
372 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
373 function. @xref{Leaf Functions}.\n\
375 On some machines, some functions pop their arguments on exit while\n\
376 others leave that for the caller to do. For example, the 68020 when\n\
377 given @option{-mrtd} pops arguments in functions that take a fixed\n\
378 number of arguments.\n\
381 @findex crtl->args.pops_args\n\
382 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
383 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
384 needs to know what was decided. The number of bytes of the current\n\
385 function'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)
390 /* Initialize target-specific 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\
395 of its own that you need to create.\n\
397 GCC calls this hook after processing the command line, but before writing\n\
398 any assembly code, and before calling any of the section-returning hooks\n\
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. */
408 "Output assembly directives to switch to section @var{name}. The section\n\
409 should have attributes as specified by @var{flags}, which is a bit mask\n\
410 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
411 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
412 this section is associated.",
413 void, (const char *name, unsigned int flags, tree decl),
414 default_no_named_section)
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. */
425 "Return preferred text (sub)section for function @var{decl}.\n\
426 Main purpose of this function is to separate cold, normal and hot\n\
427 functions. @var{startup} is true when function is known to be used only\n\
428 at 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\
431 Return 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)
435 /* Output the assembler code for function exit. */
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)
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. */
452 "Return a mask describing how relocations should be treated when\n\
453 selecting sections. Bit 1 should be set if global relocations\n\
454 should be placed in a read-write section; bit 0 should be set if\n\
455 local relocations should be placed in a read-write section.\n\
457 The default version of this function returns 3 when @option{-fpic}\n\
458 is in effect, and 0 otherwise. The hook is typically redefined\n\
459 when the target cannot support (some kinds of) dynamic relocations\n\
460 in read-only sections even in executables.",
462 default_reloc_rw_mask)
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. */
470 "Return the section into which @var{exp} should be placed. You can\n\
471 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
472 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
473 requires link-time relocations. Bit 0 is set when variable contains\n\
474 local relocations only, while bit 1 is set for global relocations.\n\
475 @var{align} is the constant alignment in bits.\n\
477 The default version of this function takes care of putting read-only\n\
478 variables in @code{readonly_data_section}.\n\
480 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
481 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
482 default_select_section)
484 /* Return a section for X. MODE is X's mode and ALIGN is its
485 alignment in bits. */
488 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
489 should be placed. You can assume that @var{x} is some kind of\n\
490 constant in RTL@. The argument @var{mode} is redundant except in the\n\
491 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
494 The default version of this function takes care of putting symbolic\n\
495 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
496 else in @code{readonly_data_section}.",
497 section *, (enum machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
498 default_select_rtx_section)
500 /* Select a unique section name for DECL. RELOC is the same as
501 for SELECT_SECTION. */
504 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
505 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
506 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
507 the initial value of @var{exp} requires link-time relocations.\n\
509 The default version of this function appends the symbol name to the\n\
510 ELF section name that would normally be used for the symbol. For\n\
511 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
512 Whatever the actual target object format, this is often good enough.",
513 void, (tree decl, int reloc),
514 default_unique_section)
516 /* Return the readonly data section associated with function DECL. */
518 (function_rodata_section,
519 "Return the readonly data section associated with\n\
520 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
521 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
522 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
523 if function is in @code{.text.name}, and the normal readonly-data section\n\
525 section *, (tree decl),
526 default_function_rodata_section)
528 /* Nonnull if the target wants to override the default ".rodata" prefix
529 for mergeable data sections. */
531 (mergeable_rodata_prefix,
532 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
533 section names for mergeable constant data. Define this macro to override\n\
534 the string if a different section name should be used.",
535 const char *, ".rodata")
537 /* Return the section to be used for transactional memory clone tables. */
539 (tm_clone_table_section,
540 "Return the section that should be used for transactional memory clone\
542 section *, (void), default_clone_table_section)
544 /* Output a constructor for a symbol with a given priority. */
547 "If defined, a function that outputs assembler code to arrange to call\n\
548 the function referenced by @var{symbol} at initialization time.\n\
550 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
551 no arguments and with no return value. If the target supports initialization\n\
552 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
553 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
555 If this macro is not defined by the target, a suitable default will\n\
556 be chosen if (1) the target supports arbitrary section names, (2) the\n\
557 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
559 void, (rtx symbol, int priority), NULL)
561 /* Output a destructor for a symbol with a given priority. */
564 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
565 functions rather than initialization functions.",
566 void, (rtx symbol, int priority), NULL)
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. */
575 "A function that outputs the assembler code for a thunk\n\
576 function, used to implement C++ virtual function calls with multiple\n\
577 inheritance. The thunk acts as a wrapper around a virtual function,\n\
578 adjusting the implicit object parameter before handing control off to\n\
579 the real function.\n\
581 First, emit code to add the integer @var{delta} to the location that\n\
582 contains the incoming first argument. Assume that this argument\n\
583 contains a pointer, and is the one used to pass the @code{this} pointer\n\
584 in C++. This is the incoming argument @emph{before} the function prologue,\n\
585 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
586 all other incoming arguments.\n\
588 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
589 made after adding @code{delta}. In particular, if @var{p} is the\n\
590 adjusted pointer, the following adjustment should be made:\n\
593 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
596 After 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\
598 not touch the return address. Hence returning from @var{FUNCTION} will\n\
599 return to whoever called the current @samp{thunk}.\n\
601 The effect must be as if @var{function} had been called directly with\n\
602 the adjusted first argument. This macro is responsible for emitting all\n\
603 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
604 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
606 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
607 have already been extracted from it.) It might possibly be useful on\n\
608 some targets, but probably not.\n\
610 If you do not define this macro, the target-independent code in the C++\n\
611 front end will generate a less efficient heavyweight thunk that calls\n\
612 @var{function} instead of jumping to it. The generic approach does\n\
613 not support varargs.",
614 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
615 HOST_WIDE_INT vcall_offset, tree function),
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. */
625 (can_output_mi_thunk,
626 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
627 to output the assembler code for the thunk function specified by the\n\
628 arguments it is passed, and false otherwise. In the latter case, the\n\
629 generic approach will be used by the C++ front end, with the limitations\n\
630 previously 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)
635 /* Output any boilerplate text needed at the beginning of a
639 "Output to @code{asm_out_file} any text which the assembler expects to\n\
640 find at the beginning of a file. The default behavior is controlled\n\
641 by two flags, documented below. Unless your target's assembler is\n\
642 quite unusual, if you override the default, you should call\n\
643 @code{default_file_start} at some point in your target hook. This\n\
644 lets other target files rely on these variables.",
648 /* Output any boilerplate text needed at the end of a translation unit. */
651 "Output to @code{asm_out_file} any text which the assembler expects\n\
652 to find at the end of a file. The default is to output nothing.",
656 /* Output any boilerplate text needed at the beginning of an
657 LTO output stream. */
660 "Output to @code{asm_out_file} any text which the assembler expects\n\
661 to find at the start of an LTO section. The default is to output\n\
666 /* Output any boilerplate text needed at the end of an
667 LTO output stream. */
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671 to find at the end of an LTO section. The default is to output\n\
676 /* Output any boilerplace text needed at the end of a
677 translation unit before debug and unwind info is emitted. */
680 "Output to @code{asm_out_file} any text which is needed before emitting\n\
681 unwind info and debug info at the end of a file. Some targets emit\n\
682 here PIC setup thunks that cannot be emitted at the end of file,\n\
683 because they couldn't have unwind info then. The default is to output\n\
688 /* Output an assembler pseudo-op to declare a library function name
692 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
693 pseudo-op to declare a library function name external. The name of the\n\
694 library function is given by @var{symref}, which is a @code{symbol_ref}.",
696 default_external_libcall)
698 /* Output an assembler directive to mark decl live. This instructs
699 linker to not dead code strip this symbol. */
701 (mark_decl_preserved,
702 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
703 directive 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)
708 /* Output a record of the command line switches that have been passed. */
710 (record_gcc_switches,
711 "Provides the target with the ability to record the gcc command line\n\
712 switches that have been passed to the compiler, and options that are\n\
713 enabled. The @var{type} argument specifies what is being recorded.\n\
714 It can take the following values:\n\
717 @item SWITCH_TYPE_PASSED\n\
718 @var{text} is a command line switch that has been set by the user.\n\
720 @item SWITCH_TYPE_ENABLED\n\
721 @var{text} is an option which has been enabled. This might be as a\n\
722 direct result of a command line switch, or because it is enabled by\n\
723 default or because it has been enabled as a side effect of a different\n\
724 command line switch. For example, the @option{-O2} switch enables\n\
725 various different individual optimization passes.\n\
727 @item SWITCH_TYPE_DESCRIPTIVE\n\
728 @var{text} is either NULL or some descriptive text which should be\n\
729 ignored. If @var{text} is NULL then it is being used to warn the\n\
730 target hook that either recording is starting or ending. The first\n\
731 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
732 warning is for start up and the second time the warning is for\n\
733 wind down. This feature is to allow the target hook to make any\n\
734 necessary preparations before it starts to record switches and to\n\
735 perform any necessary tidying up after it has finished recording\n\
738 @item SWITCH_TYPE_LINE_START\n\
739 This option can be ignored by this target hook.\n\
741 @item SWITCH_TYPE_LINE_END\n\
742 This option can be ignored by this target hook.\n\
745 The hook's return value must be zero. Other return values may be\n\
746 supported in the future.\n\
748 By default this hook is set to NULL, but an example implementation is\n\
749 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
750 it records the switches as ASCII text inside a new, string mergeable\n\
751 section in the assembler output file. The name of the new section is\n\
752 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
754 int, (print_switch_type type, const char *text),
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
762 (record_gcc_switches_section,
763 "This is the name of the section that will be created by the example\n\
764 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
766 const char *, ".GCC.command.line")
768 /* Output the definition of a section 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\
773 The hook is called with the assembly output position set to the beginning\n\
774 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
776 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
777 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
778 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
779 is @code{NULL}, which disables the use of section anchors altogether.",
781 default_asm_output_anchor)
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} \
789 void, (const char *name),
790 hook_void_constcharptr)
792 /* Output a DTP-relative reference to a TLS symbol. */
794 (output_dwarf_dtprel,
795 "If defined, this target hook is a function which outputs a DTP-relative\n\
796 reference to the given TLS symbol of the specified size.",
797 void, (FILE *file, int size, rtx x),
800 /* Some target machines need to postscan each insn after it is output. */
802 (final_postscan_insn,
803 "If defined, this target hook is a function which is executed just after the\n\
804 output of assembler code for @var{insn}, to change the mode of the assembler\n\
807 Here the argument @var{opvec} is the vector containing the operands\n\
808 extracted from @var{insn}, and @var{noperands} is the number of\n\
809 elements of the vector which contain meaningful data for this insn.\n\
810 The contents of this vector are what was used to convert the insn\n\
811 template into assembler code, so you can change the assembler mode\n\
812 by checking the contents of the vector.",
813 void, (FILE *file, rtx insn, rtx *opvec, int noperands),
816 /* Emit the trampoline template. This hook may be NULL. */
818 (trampoline_template,
819 "This hook is called by @code{assemble_trampoline_template} to output,\n\
820 on the stream @var{f}, assembler code for a block of data that contains\n\
821 the constant parts of a trampoline. This code should not include a\n\
822 label---the label is taken care of automatically.\n\
824 If you do not define this hook, it means no template is needed\n\
825 for the target. Do not define this hook on systems where the block move\n\
826 code to copy the trampoline into place would be larger than the code\n\
827 to generate it on the spot.",
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\
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)
843 (output_addr_const_extra,
844 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
845 can't deal with, and output assembly code to @var{file} corresponding to\n\
846 the pattern @var{x}. This may be used to allow machine-dependent\n\
847 @code{UNSPEC}s to appear within constants.\n\
849 If target hook fails to recognize a pattern, it must return @code{false},\n\
850 so that a standard error message is printed. If it prints an error message\n\
851 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
852 return @code{true}.",
853 bool, (FILE *file, rtx x),
854 hook_bool_FILEptr_rtx_false)
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
860 #define HOOK_PREFIX "TARGET_"
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. */
868 void, (FILE *file, rtx x, int code),
869 default_print_operand)
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. */
875 (print_operand_address,
877 void, (FILE *file, rtx addr),
878 default_print_operand_address)
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,
885 (print_operand_punct_valid_p,
887 bool ,(unsigned char code),
888 default_print_operand_punct_valid_p)
890 /* Given a symbol name, perform same mangling as assemble_name and
891 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
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)
902 HOOK_VECTOR_END (asm_out)
904 /* Functions relating to instruction scheduling. All of these
905 default to null pointers, which haifa-sched.c looks for and handles. */
907 #define HOOK_PREFIX "TARGET_SCHED_"
908 HOOK_VECTOR (TARGET_SCHED, sched)
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. */
915 "This function corrects the value of @var{cost} based on the\n\
916 relationship between @var{insn} and @var{dep_insn} through the\n\
917 dependence @var{link}. It should return the new value. The default\n\
918 is to make no adjustment to @var{cost}. This can be used for example\n\
919 to specify to the scheduler using the traditional pipeline description\n\
920 that an output- or anti-dependence does not incur the same cost as a\n\
921 data-dependence. If the scheduler using the automaton based pipeline\n\
922 description, the cost of anti-dependence is zero and the cost of\n\
923 output-dependence is maximum of one and the difference of latency\n\
924 times of the first and the second insns. If these values are not\n\
925 acceptable, 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)
929 /* Adjust the priority of an insn as you see fit. Returns the new 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\
934 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
935 later. Do not define this hook if you do not need to adjust the\n\
936 scheduling priorities of insns.",
937 int, (rtx insn, int priority), NULL)
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. */
944 "This hook returns the maximum number of instructions that can ever\n\
945 issue at the same time on the target machine. The default is one.\n\
946 Although the insn scheduler can define itself the possibility of issue\n\
947 an insn on the same cycle, the value can serve as an additional\n\
948 constraint to issue insns on the same simulated processor cycle (see\n\
949 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
950 This value must be constant over the entire compilation. If you need\n\
951 it to vary depending on what the instructions are, you must use\n\
952 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
955 /* Calculate how much this insn affects how many more insns we
956 can emit this cycle. Default is they all cost the same. */
959 "This hook is executed by the scheduler after it has scheduled an insn\n\
960 from the ready list. It should return the number of insns which can\n\
961 still 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\
964 You should define this hook if some insns take more machine resources\n\
965 than 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\
967 debug output to. @var{verbose} is the verbose level provided by\n\
968 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
970 int, (FILE *file, int verbose, rtx insn, int more), NULL)
972 /* Initialize machine-dependent scheduling code. */
975 "This hook is executed by the scheduler at the beginning of each block of\n\
976 instructions that are to be scheduled. @var{file} is either a null\n\
977 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
978 is 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\
980 region that can be live at the same time. This can be used to allocate\n\
981 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
982 void, (FILE *file, int verbose, int max_ready), NULL)
984 /* Finalize machine-dependent scheduling code. */
987 "This hook is executed by the scheduler at the end of each block of\n\
988 instructions that are to be scheduled. It can be used to perform\n\
989 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
990 is either a null pointer, or a stdio stream to write any debug output\n\
991 to. @var{verbose} is the verbose level provided by\n\
992 @option{-fsched-verbose-@var{n}}.",
993 void, (FILE *file, int verbose), NULL)
995 /* Initialize machine-dependent function wide scheduling code. */
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)
1004 /* Finalize machine-dependent function wide scheduling code. */
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)
1012 /* Reorder insns in a machine-dependent fashion, in two different
1013 places. Default does nothing. */
1016 "This hook is executed by the scheduler after it has scheduled the ready\n\
1017 list, to allow the machine description to reorder it (for example to\n\
1018 combine 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\
1020 debug 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\
1022 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1023 a pointer to the number of elements in the ready list. The scheduler\n\
1024 reads 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\
1026 is the timer tick of the scheduler. You may modify the ready list and\n\
1027 the number of ready insns. The return value is the number of insns that\n\
1028 can 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)
1034 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1035 function is called whenever the scheduler starts a new cycle. This one\n\
1036 is called once per iteration over a cycle, immediately after\n\
1037 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1038 return the number of insns to be scheduled in the same cycle. Defining\n\
1039 this hook can be useful if there are frequent situations where\n\
1040 scheduling one insn causes other insns to become ready in the same\n\
1041 cycle. These other insns can then be taken into account properly.",
1042 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)
1046 "This hook is used to check whether target platform supports macro fusion.",
1050 (macro_fusion_pair_p,
1051 "This hook is used to check whether two insns could be macro fused for\n\
1052 target 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\
1054 group, and they will not be scheduled apart.",
1055 bool, (rtx condgen, rtx condjmp), NULL)
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). */
1061 (dependencies_evaluation_hook,
1062 "This hook is called after evaluation forward dependencies of insns in\n\
1063 chain given by two parameter values (@var{head} and @var{tail}\n\
1064 correspondingly) but before insns scheduling of the insn chain. For\n\
1065 example, it can be used for better insn classification if it requires\n\
1066 analysis of dependencies. This hook can use backward and forward\n\
1067 dependencies of the insn scheduler because they are already\n\
1069 void, (rtx head, rtx tail), NULL)
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. */
1082 (init_dfa_pre_cycle_insn,
1083 "The hook can be used to initialize data used by the previous hook.",
1087 (dfa_pre_cycle_insn,
1088 "The hook returns an RTL insn. The automaton state used in the\n\
1089 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1090 when the new simulated processor cycle starts. Usage of the hook may\n\
1091 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1092 processors. If the hook is defined, it is used only for the automaton\n\
1093 based pipeline description. The default is not to change the state\n\
1094 when the new simulated processor cycle starts.",
1098 (init_dfa_post_cycle_insn,
1099 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1100 used to initialize data used by the previous hook.",
1104 (dfa_post_cycle_insn,
1105 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1106 to changed the state as if the insn were scheduled when the new\n\
1107 simulated processor cycle finishes.",
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. */
1116 (dfa_pre_advance_cycle,
1117 "The hook to notify target that the current simulated cycle is about to finish.\n\
1118 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1119 to change the state in more complicated situations - e.g., when advancing\n\
1120 state on a single insn is not enough.",
1124 (dfa_post_advance_cycle,
1125 "The hook to notify target that new simulated cycle has just started.\n\
1126 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1127 to change the state in more complicated situations - e.g., when advancing\n\
1128 state on a single insn is not enough.",
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. */
1139 (first_cycle_multipass_dfa_lookahead,
1140 "This hook controls better choosing an insn from the ready insn queue\n\
1141 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1142 chooses the first insn from the queue. If the hook returns a positive\n\
1143 value, an additional scheduler code tries all permutations of\n\
1144 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1145 subsequent ready insns to choose an insn whose issue will result in\n\
1146 maximal number of issued insns on the same cycle. For the\n\
1147 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1148 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1149 rules of @acronym{VLIW} packing are described in the automaton.\n\
1151 This code also could be used for superscalar @acronym{RISC}\n\
1152 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1153 with 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\
1156 processor 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\
1158 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1159 the processor could issue all 3 insns per cycle.\n\
1161 Actually this code demonstrates advantages of the automaton based\n\
1162 pipeline hazard recognizer. We try quickly and easy many insn\n\
1163 schedules to choose the best one.\n\
1165 The default is no multipass scheduling.",
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. */
1173 (first_cycle_multipass_dfa_lookahead_guard,
1175 This hook controls what insns from the ready insn queue will be\n\
1176 considered for the multipass insn scheduling. If the hook returns\n\
1177 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1178 Positive return values will remove @var{insn} from consideration on\n\
1179 the current round of multipass scheduling.\n\
1180 Negative return values will remove @var{insn} from consideration for given\n\
1181 number of cycles.\n\
1182 Backends should be careful about returning non-zero for highest priority\n\
1183 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1184 to allow backends make correct judgements.\n\
1186 The default is that any ready insns can be chosen to be issued.",
1187 int, (rtx insn, int ready_index), NULL)
1189 /* This hook prepares the target for a new round of multipass
1191 DATA is a pointer to target-specific data used for multipass scheduling.
1192 READY_TRY and N_READY represent the current state of search in the
1193 optimization space. The target can filter out instructions that
1194 should not be tried during current round by setting corresponding
1195 elements in READY_TRY to non-zero.
1196 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1197 scheduling on current cycle. */
1199 (first_cycle_multipass_begin,
1200 "This hook prepares the target backend for a new round of multipass\n\
1202 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1205 /* This hook is called when multipass scheduling evaluates instruction INSN.
1206 DATA is a pointer to target-specific data that can be used to record effects
1207 of INSN on CPU that are not described in DFA.
1208 READY_TRY and N_READY represent the current state of search in the
1209 optimization space. The target can filter out instructions that
1210 should not be tried after issuing INSN by setting corresponding
1211 elements in READY_TRY to non-zero.
1212 INSN is the instruction being evaluated.
1213 PREV_DATA is a pointer to target-specific data corresponding
1214 to a state before issuing INSN. */
1216 (first_cycle_multipass_issue,
1217 "This hook is called when multipass scheduling evaluates instruction INSN.",
1218 void, (void *data, signed char *ready_try, int n_ready, rtx insn,
1219 const void *prev_data), NULL)
1221 /* This hook is called when multipass scheduling backtracks from evaluation of
1222 instruction corresponding to DATA.
1223 DATA is a pointer to target-specific data that stores the effects
1224 of instruction from which the algorithm backtracks on CPU that are not
1226 READY_TRY and N_READY represent the current state of search in the
1227 optimization space. The target can filter out instructions that
1228 should not be tried after issuing INSN by setting corresponding
1229 elements in READY_TRY to non-zero. */
1231 (first_cycle_multipass_backtrack,
1232 "This is called when multipass scheduling backtracks from evaluation of\n\
1234 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1236 /* This hook notifies the target about the result of the concluded current
1237 round of multipass scheduling.
1239 If DATA is non-NULL it points to target-specific data used for multipass
1240 scheduling which corresponds to instruction at the start of the chain of
1241 the winning solution. DATA is NULL when multipass scheduling cannot find
1242 a good enough solution on current cycle and decides to retry later,
1243 usually after advancing the cycle count. */
1245 (first_cycle_multipass_end,
1246 "This hook notifies the target about the result of the concluded current\n\
1247 round of multipass scheduling.",
1248 void, (const void *data), NULL)
1250 /* This hook is called to initialize target-specific data for multipass
1251 scheduling after it has been allocated.
1252 DATA is a pointer to target-specific data that stores the effects
1253 of instruction from which the algorithm backtracks on CPU that are not
1254 described in DFA. */
1256 (first_cycle_multipass_init,
1257 "This hook initializes target-specific data used in multipass scheduling.",
1258 void, (void *data), NULL)
1260 /* This hook is called to finalize target-specific data for multipass
1261 scheduling before it is deallocated.
1262 DATA is a pointer to target-specific data that stores the effects
1263 of instruction from which the algorithm backtracks on CPU that are not
1264 described in DFA. */
1266 (first_cycle_multipass_fini,
1267 "This hook finalizes target-specific data used in multipass scheduling.",
1268 void, (void *data), NULL)
1270 /* The following member value is pointer to a function called by
1271 the insn scheduler before issuing insn passed as the third
1272 parameter on given cycle. If the hook returns nonzero, the
1273 insn is not issued on given processors cycle. Instead of that,
1274 the processor cycle is advanced. If the value passed through
1275 the last parameter is zero, the insn ready queue is not sorted
1276 on the new cycle start as usually. The first parameter passes
1277 file for debugging output. The second one passes the scheduler
1278 verbose level of the debugging output. The forth and the fifth
1279 parameter values are correspondingly processor cycle on which
1280 the previous insn has been issued and the current processor cycle. */
1283 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1284 on cycle @var{clock}. If the hook returns nonzero,\n\
1285 @var{insn} is not issued on this processor cycle. Instead,\n\
1286 the processor cycle is advanced. If *@var{sort_p}\n\
1287 is zero, the insn ready queue is not sorted on the new cycle\n\
1288 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1289 verbosity level to use for debugging output.\n\
1290 @var{last_clock} and @var{clock} are, respectively, the\n\
1291 processor cycle on which the previous insn has been issued,\n\
1292 and the current processor cycle.",
1293 int, (FILE *dump, int verbose, rtx insn, int last_clock,
1294 int clock, int *sort_p),
1297 /* The following member value is a pointer to a function called by the
1298 insn scheduler. It should return true if there exists a dependence
1299 which is considered costly by the target, between the insn
1300 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1301 the dep that represents the dependence between the two insns. The
1302 second argument is the cost of the dependence as estimated by
1303 the scheduler. The last argument is the distance in cycles
1304 between the already scheduled insn (first parameter) and the
1305 second insn (second parameter). */
1307 (is_costly_dependence,
1308 "This hook is used to define which dependences are considered costly by\n\
1309 the target, so costly that it is not advisable to schedule the insns that\n\
1310 are involved in the dependence too close to one another. The parameters\n\
1311 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1312 being evaluated. The second parameter @var{cost} is the cost of the\n\
1313 dependence as estimated by the scheduler, and the third\n\
1314 parameter @var{distance} is the distance in cycles between the two insns.\n\
1315 The hook returns @code{true} if considering the distance between the two\n\
1316 insns the dependence between them is considered costly by the target,\n\
1317 and @code{false} otherwise.\n\
1319 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1320 where (a) it's practically hopeless to predict the actual data/resource\n\
1321 delays, however: (b) there's a better chance to predict the actual grouping\n\
1322 that will be formed, and (c) correctly emulating the grouping can be very\n\
1323 important. In such targets one may want to allow issuing dependent insns\n\
1324 closer to one another---i.e., closer than the dependence distance; however,\n\
1325 not in cases of ``costly dependences'', which this hooks allows to define.",
1326 bool, (struct _dep *_dep, int cost, int distance), NULL)
1330 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1331 return a new cost based on its relationship to @var{dep_insn} through the\
1332 dependence of weakness @var{dw}. The default is to make no adjustment.",
1333 int, (rtx insn, int dep_type1, rtx dep_insn, int cost, unsigned int dw), NULL)
1335 /* The following member value is a pointer to a function called
1336 by the insn scheduler. This hook is called to notify the backend
1337 that new instructions were emitted. */
1340 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1341 the instruction stream. The hook notifies a target backend to extend its\n\
1342 per instruction data structures.",
1345 /* Next 5 functions are for multi-point scheduling. */
1347 /* Allocate memory for scheduler context. */
1349 (alloc_sched_context,
1350 "Return a pointer to a store large enough to hold target scheduling context.",
1351 void *, (void), NULL)
1353 /* Fills the context from the local machine scheduler context. */
1355 (init_sched_context,
1356 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1357 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1358 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1359 void, (void *tc, bool clean_p), NULL)
1361 /* Sets local machine scheduler context to a saved value. */
1364 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1365 void, (void *tc), NULL)
1367 /* Clears a scheduler context so it becomes like after init. */
1369 (clear_sched_context,
1370 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1371 void, (void *tc), NULL)
1373 /* Frees the scheduler context. */
1375 (free_sched_context,
1376 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1377 void, (void *tc), NULL)
1379 /* The following member value is a pointer to a function called
1380 by the insn scheduler.
1381 The first parameter is an instruction, the second parameter is the type
1382 of the requested speculation, and the third parameter is a pointer to the
1383 speculative pattern of the corresponding type (set if return value == 1).
1385 -1, if there is no pattern, that will satisfy the requested speculation type,
1386 0, if current pattern satisfies the requested speculation type,
1387 1, if pattern of the instruction should be changed to the newly
1391 "This hook is called by the insn scheduler when @var{insn} has only\n\
1392 speculative dependencies and therefore can be scheduled speculatively.\n\
1393 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1394 version and, in case of successful check, to generate that speculative\n\
1395 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1396 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1397 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1398 the generated speculative pattern.",
1399 int, (rtx insn, unsigned int dep_status, rtx *new_pat), NULL)
1401 /* The following member value is a pointer to a function called
1402 by the insn scheduler. It should return true if the check instruction
1403 passed as the parameter needs a recovery block. */
1406 "This hook is called by the insn scheduler during generation of recovery code\n\
1407 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1408 instruction should branch to recovery code, or @code{false} otherwise.",
1409 bool, (unsigned int dep_status), NULL)
1411 /* The following member value is a pointer to a function called
1412 by the insn scheduler. It should return a pattern for the check
1414 The first parameter is a speculative instruction, the second parameter
1415 is the label of the corresponding recovery block (or null, if it is a
1416 simple check). The third parameter is the kind of speculation that
1417 is being performed. */
1420 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1421 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1422 speculative instruction for which the check should be generated.\n\
1423 @var{label} is either a label of a basic block, where recovery code should\n\
1424 be emitted, or a null pointer, when requested check doesn't branch to\n\
1425 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1426 a pattern for a branchy check corresponding to a simple check denoted by\n\
1427 @var{insn} should be generated. In this case @var{label} can't be null.",
1428 rtx, (rtx insn, rtx label, unsigned int ds), NULL)
1430 /* The following member value is a pointer to a function that provides
1431 information about the speculation capabilities of the target.
1432 The parameter is a pointer to spec_info variable. */
1435 "This hook is used by the insn scheduler to find out what features should be\n\
1437 The structure *@var{spec_info} should be filled in by the target.\n\
1438 The structure describes speculation types that can be used in the scheduler.",
1439 void, (struct spec_info_def *spec_info), NULL)
1443 "Return speculation types of instruction @var{insn}.",
1444 unsigned int, (rtx insn), NULL)
1447 (get_insn_checked_ds,
1448 "Return speculation types that are checked for instruction @var{insn}",
1449 unsigned int, (rtx insn), NULL)
1453 "Return bool if rtx scanning should just skip current layer and\
1454 advance to the inner rtxes.",
1455 bool, (const_rtx x), NULL)
1457 /* The following member value is a pointer to a function that provides
1458 information about the target resource-based lower bound which is
1459 used by the swing modulo scheduler. The parameter is a pointer
1463 "This hook is called by the swing modulo scheduler to calculate a\n\
1464 resource-based lower bound which is based on the resources available in\n\
1465 the machine and the resources required by each instruction. The target\n\
1466 backend can use @var{g} to calculate such bound. A very simple lower\n\
1467 bound will be used in case this hook is not implemented: the total number\n\
1468 of instructions divided by the issue rate.",
1469 int, (struct ddg *g), NULL)
1471 /* The following member value is a function that initializes dispatch
1472 schedling and adds instructions to dispatch window according to its
1476 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1477 in its second parameter.",
1478 void, (rtx insn, int x),
1481 /* The following member value is a a function that returns true is
1482 dispatch schedling is supported in hardware and condition passed
1483 as the second parameter is true. */
1486 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1487 is supported in hardware and the condition specified in the parameter is true.",
1488 bool, (rtx insn, int x),
1489 hook_bool_rtx_int_false)
1493 "True if the processor has an exposed pipeline, which means that not just\n\
1494 the order of instructions is important for correctness when scheduling, but\n\
1495 also the latencies of operations.",
1498 /* The following member value is a function that returns number
1499 of operations reassociator should try to put in parallel for
1500 statements of the given type. By default 1 is used. */
1502 (reassociation_width,
1503 "This hook is called by tree reassociator to determine a level of\n\
1504 parallelism required in output calculations chain.",
1505 int, (unsigned int opc, enum machine_mode mode),
1506 hook_int_uint_mode_1)
1508 HOOK_VECTOR_END (sched)
1510 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1512 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1513 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1516 (compute_vecsize_and_simdlen,
1517 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1518 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1519 @var{simdlen} field if it was previously 0.\n\
1520 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1521 or number of @var{vecsize_mangle} variants that should be emitted.",
1522 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1526 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1527 to SIMD clone @var{node} if needed.",
1528 void, (struct cgraph_node *), NULL)
1532 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1533 in vectorized loops in current function, or non-negative number if it is\n\
1534 usable. In that case, the smaller the number is, the more desirable it is\n\
1536 int, (struct cgraph_node *), NULL)
1538 HOOK_VECTOR_END (simd_clone)
1540 /* Functions relating to vectorization. */
1542 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1543 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1545 /* The following member value is a pointer to a function called
1546 by the vectorizer, and return the decl of the target builtin
1549 (builtin_mask_for_load,
1550 "This hook should return the DECL of a function @var{f} that given an\n\
1551 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1552 used to extract from two vectors the relevant data that resides in\n\
1553 @var{addr} in case @var{addr} is not properly aligned.\n\
1555 The autovectorizer, when vectorizing a load operation from an address\n\
1556 @var{addr} that may be unaligned, will generate two vector loads from\n\
1557 the two aligned addresses around @var{addr}. It then generates a\n\
1558 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1559 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1560 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1561 the third argument, @var{OFF}, defines how the data will be extracted\n\
1562 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1563 @var{v2}; otherwise, the returned vector is composed from the last\n\
1564 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1565 @var{OFF} elements of @var{v2}.\n\
1567 If this hook is defined, the autovectorizer will generate a call\n\
1568 to @var{f} (using the DECL tree that this hook returns) and will\n\
1569 use the return value of @var{f} as the argument @var{OFF} to\n\
1570 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1571 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1573 If this hook is not defined, then @var{addr} will be used as\n\
1574 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1575 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1578 /* Returns a code for builtin that realizes vectorized version of
1579 function, or NULL_TREE if not available. */
1581 (builtin_vectorized_function,
1582 "This hook should return the decl of a function that implements the\n\
1583 vectorized variant of the builtin function with builtin function code\n\
1584 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1585 The value of @var{fndecl} is the builtin function declaration. The\n\
1586 return type of the vectorized function shall be of vector type\n\
1587 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1588 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1589 default_builtin_vectorized_function)
1591 /* Returns a function declaration for a builtin that realizes the
1592 vector conversion, or NULL_TREE if not available. */
1594 (builtin_conversion,
1595 "This hook should return the DECL of a function that implements conversion of the\n\
1596 input vector of type @var{src_type} to type @var{dest_type}.\n\
1597 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1598 specifies how the conversion is to be applied\n\
1599 (truncation, rounding, etc.).\n\
1601 If this hook is defined, the autovectorizer will use the\n\
1602 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1603 conversion. Otherwise, it will return @code{NULL_TREE}.",
1604 tree, (unsigned code, tree dest_type, tree src_type),
1605 default_builtin_vectorized_conversion)
1607 /* Cost of different vector/scalar statements in vectorization cost
1608 model. In case of misaligned vector loads and stores the cost depends
1609 on the data type and misalignment value. */
1611 (builtin_vectorization_cost,
1612 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1613 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1614 misalignment value (@var{misalign}).",
1615 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1616 default_builtin_vectorization_cost)
1618 /* Return true if vector alignment is reachable (by peeling N
1619 iterations) for the given type. */
1621 (vector_alignment_reachable,
1622 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1623 bool, (const_tree type, bool is_packed),
1624 default_builtin_vector_alignment_reachable)
1626 /* Return true if a vector created for vec_perm_const is valid.
1627 A NULL indicates that all constants are valid permutations. */
1630 "Return true if a vector created for @code{vec_perm_const} is valid.",
1631 bool, (enum machine_mode, const unsigned char *sel),
1634 /* Return true if the target supports misaligned store/load of a
1635 specific factor denoted in the third parameter. The last parameter
1636 is true if the access is defined in a packed struct. */
1638 (support_vector_misalignment,
1639 "This hook should return true if the target supports misaligned vector\n\
1640 store/load of a specific factor denoted in the @var{misalignment}\n\
1641 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1642 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1643 parameter is true if the memory access is defined in a packed struct.",
1645 (enum machine_mode mode, const_tree type, int misalignment, bool is_packed),
1646 default_builtin_support_vector_misalignment)
1648 /* Return the builtin decl needed to load a vector of TYPE. */
1651 "This hook should return the built-in decl needed to load a vector of the "
1652 "given type within a transaction.",
1655 default_builtin_tm_load_store)
1657 /* Return the builtin decl needed to store a vector of TYPE. */
1660 "This hook should return the built-in decl needed to store a vector of the "
1661 "given type within a transaction.",
1664 default_builtin_tm_load_store)
1666 /* Returns the preferred mode for SIMD operations for the specified
1669 (preferred_simd_mode,
1670 "This hook should return the preferred mode for vectorizing scalar\n\
1671 mode @var{mode}. The default is\n\
1672 equal to @code{word_mode}, because the vectorizer can do some\n\
1673 transformations even in absence of specialized @acronym{SIMD} hardware.",
1675 (enum machine_mode mode),
1676 default_preferred_simd_mode)
1678 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1679 after processing the preferred one derived from preferred_simd_mode. */
1681 (autovectorize_vector_sizes,
1682 "This hook should return a mask of sizes that should be iterated over\n\
1683 after trying to autovectorize using the vector size derived from the\n\
1684 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1685 The default is zero which means to not iterate over other vector sizes.",
1688 default_autovectorize_vector_sizes)
1690 /* Target builtin that implements vector gather operation. */
1693 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1694 is the vector type of the load and @var{index_type} is scalar type of\n\
1695 the index, scaled by @var{scale}.\n\
1696 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1699 (const_tree mem_vectype, const_tree index_type, int scale),
1702 /* Target function to initialize the cost model for a loop or block. */
1705 "This hook should initialize target-specific data structures in preparation "
1706 "for modeling the costs of vectorizing a loop or basic block. The default "
1707 "allocates three unsigned integers for accumulating costs for the prologue, "
1708 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1709 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1710 "is being vectorized.",
1712 (struct loop *loop_info),
1715 /* Target function to record N statements of the given kind using the
1716 given vector type within the cost model data for the current loop or
1720 "This hook should update the target-specific @var{data} in response to "
1721 "adding @var{count} copies of the given @var{kind} of statement to a "
1722 "loop or basic block. The default adds the builtin vectorizer cost for "
1723 "the copies of the statement to the accumulator specified by @var{where}, "
1724 "(the prologue, body, or epilogue) and returns the amount added. The "
1725 "return value should be viewed as a tentative cost that may later be "
1728 (void *data, int count, enum vect_cost_for_stmt kind,
1729 struct _stmt_vec_info *stmt_info, int misalign,
1730 enum vect_cost_model_location where),
1731 default_add_stmt_cost)
1733 /* Target function to calculate the total cost of the current vectorized
1737 "This hook should complete calculations of the cost of vectorizing a loop "
1738 "or basic block based on @var{data}, and return the prologue, body, and "
1739 "epilogue costs as unsigned integers. The default returns the value of "
1740 "the three accumulators.",
1742 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1743 unsigned *epilogue_cost),
1744 default_finish_cost)
1746 /* Function to delete target-specific cost modeling data. */
1749 "This hook should release @var{data} and any related data structures "
1750 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1754 default_destroy_cost_data)
1756 HOOK_VECTOR_END (vectorize)
1759 #define HOOK_PREFIX "TARGET_"
1761 /* Allow target specific overriding of option settings after options have
1762 been changed by an attribute or pragma or when it is reset at the
1763 end of the code affected by an attribute or pragma. */
1765 (override_options_after_change,
1766 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1767 but is called when the optimize level is changed via an attribute or\n\
1768 pragma or when it is reset at the end of the code affected by the\n\
1769 attribute or pragma. It is not called at the beginning of compilation\n\
1770 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1771 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1772 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1777 (eh_return_filter_mode,
1778 "Return machine mode for filter value.",
1779 enum machine_mode, (void),
1780 default_eh_return_filter_mode)
1782 /* Return machine mode for libgcc expanded cmp instructions. */
1784 (libgcc_cmp_return_mode,
1785 "This target hook should return the mode to be used for the return value\n\
1786 of compare instructions expanded to libgcc calls. If not defined\n\
1787 @code{word_mode} is returned which is the right choice for a majority of\n\
1789 enum machine_mode, (void),
1790 default_libgcc_cmp_return_mode)
1792 /* Return machine mode for libgcc expanded shift instructions. */
1794 (libgcc_shift_count_mode,
1795 "This target hook should return the mode to be used for the shift count operand\n\
1796 of shift instructions expanded to libgcc calls. If not defined\n\
1797 @code{word_mode} is returned which is the right choice for a majority of\n\
1799 enum machine_mode, (void),
1800 default_libgcc_shift_count_mode)
1802 /* Return machine mode to be used for _Unwind_Word type. */
1805 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
1806 The default is to use @code{word_mode}.",
1807 enum machine_mode, (void),
1808 default_unwind_word_mode)
1810 /* Given two decls, merge their attributes and return the result. */
1812 (merge_decl_attributes,
1813 "Define this target hook if the merging of decl attributes needs special\n\
1814 handling. If defined, the result is a list of the combined\n\
1815 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
1816 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
1817 when this is needed are when one attribute overrides another, or when an\n\
1818 attribute is nullified by a subsequent definition. This function may\n\
1819 call @code{merge_attributes} to handle machine-independent merging.\n\
1821 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
1822 If the only target-specific handling you require is @samp{dllimport}\n\
1823 for Microsoft Windows targets, you should define the macro\n\
1824 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
1825 will then define a function called\n\
1826 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
1827 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
1828 add @code{handle_dll_attribute} in the attribute table for your port\n\
1829 to perform initial processing of the @samp{dllimport} and\n\
1830 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
1831 @file{i386/i386.c}, for example.",
1832 tree, (tree olddecl, tree newdecl),
1833 merge_decl_attributes)
1835 /* Given two types, merge their attributes and return the result. */
1837 (merge_type_attributes,
1838 "Define this target hook if the merging of type attributes needs special\n\
1839 handling. If defined, the result is a list of the combined\n\
1840 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
1841 that @code{comptypes} has already been called and returned 1. This\n\
1842 function may call @code{merge_attributes} to handle machine-independent\n\
1844 tree, (tree type1, tree type2),
1845 merge_type_attributes)
1847 /* Table of machine attributes and functions to handle them.
1851 "If defined, this target hook points to an array of @samp{struct\n\
1852 attribute_spec} (defined in @file{tree.h}) specifying the machine\n\
1853 specific attributes for this target and some of the restrictions on the\n\
1854 entities to which these attributes are applied and the arguments they\n\
1856 const struct attribute_spec *, NULL)
1858 /* Return true iff attribute NAME expects a plain identifier as its first
1861 (attribute_takes_identifier_p,
1862 "If defined, this target hook is a function which returns true if the\n\
1863 machine-specific attribute named @var{name} expects an identifier\n\
1864 given as its first argument to be passed on as a plain identifier, not\n\
1865 subjected to name lookup. If this is not defined, the default is\n\
1866 false for all machine-specific attributes.",
1867 bool, (const_tree name),
1868 hook_bool_const_tree_false)
1870 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
1871 one if they are compatible and two if they are nearly compatible
1872 (which causes a warning to be generated). */
1874 (comp_type_attributes,
1875 "If defined, this target hook is a function which returns zero if the attributes on\n\
1876 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
1877 and two if they are nearly compatible (which causes a warning to be\n\
1878 generated). If this is not defined, machine-specific attributes are\n\
1879 supposed always to be compatible.",
1880 int, (const_tree type1, const_tree type2),
1881 hook_int_const_tree_const_tree_1)
1883 /* Assign default attributes to the newly defined TYPE. */
1885 (set_default_type_attributes,
1886 "If defined, this target hook is a function which assigns default attributes to\n\
1887 the newly defined @var{type}.",
1891 /* Insert attributes on the newly created DECL. */
1894 "Define this target hook if you want to be able to add attributes to a decl\n\
1895 when it is being created. This is normally useful for back ends which\n\
1896 wish to implement a pragma by using the attributes which correspond to\n\
1897 the pragma's effect. The @var{node} argument is the decl which is being\n\
1898 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
1899 for this decl. The list itself should not be modified, since it may be\n\
1900 shared with other decls, but attributes may be chained on the head of\n\
1901 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
1902 attributes, or a copy of the list may be made if further changes are\n\
1904 void, (tree node, tree *attr_ptr),
1905 hook_void_tree_treeptr)
1907 /* Return true if FNDECL (which has at least one machine attribute)
1908 can be inlined despite its machine attributes, false otherwise. */
1910 (function_attribute_inlinable_p,
1911 "@cindex inlining\n\
1912 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
1913 into the current function, despite its having target-specific\n\
1914 attributes, @code{false} otherwise. By default, if a function has a\n\
1915 target specific attribute attached to it, it will not be inlined.",
1916 bool, (const_tree fndecl),
1917 hook_bool_const_tree_false)
1919 /* Return true if bitfields in RECORD_TYPE should follow the
1920 Microsoft Visual C++ bitfield layout rules. */
1922 (ms_bitfield_layout_p,
1923 "This target hook returns @code{true} if bit-fields in the given\n\
1924 @var{record_type} are to be laid out following the rules of Microsoft\n\
1925 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
1926 unit with the previous bit-field if their underlying types have\n\
1927 different sizes, and the bit-field will be aligned to the highest\n\
1928 alignment of the underlying types of itself and of the previous\n\
1929 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
1930 the whole enclosing structure, even if it is unnamed; except that\n\
1931 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
1932 another bit-field of nonzero size. If this hook returns @code{true},\n\
1933 other macros that control bit-field layout are ignored.\n\
1935 When a bit-field is inserted into a packed record, the whole size\n\
1936 of the underlying type is used by one or more same-size adjacent\n\
1937 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
1938 and any additional adjacent long bit-fields are packed into the same\n\
1939 chunk of 32 bits. However, if the size changes, a new field of that\n\
1940 size is allocated). In an unpacked record, this is the same as using\n\
1941 alignment, but not equivalent when packing.\n\
1943 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
1944 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
1945 used on a single field when MS bit-fields are in use, it will take\n\
1946 precedence for that field, but the alignment of the rest of the structure\n\
1947 may affect its placement.",
1948 bool, (const_tree record_type),
1949 hook_bool_const_tree_false)
1951 /* For now this is only an interface to WORDS_BIG_ENDIAN for
1952 target-independent code like the front ends, need performance testing
1953 before switching completely to the target hook. */
1958 targhook_words_big_endian)
1960 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
1962 (float_words_big_endian,
1965 targhook_float_words_big_endian)
1968 (float_exceptions_rounding_supported_p,
1969 "Returns true if the target supports IEEE 754 floating-point exceptions\
1970 and rounding modes, false otherwise. This is intended to relate to the\
1971 @code{float} and @code{double} types, but not necessarily @code{long double}.\
1972 By default, returns true if the @code{adddf3} instruction pattern is\
1973 available and false otherwise, on the assumption that hardware floating\
1974 point supports exceptions and rounding modes but software floating point\
1977 default_float_exceptions_rounding_supported_p)
1979 /* True if the target supports decimal floating point. */
1981 (decimal_float_supported_p,
1982 "Returns true if the target supports decimal floating point.",
1984 default_decimal_float_supported_p)
1986 /* True if the target supports fixed-point. */
1988 (fixed_point_supported_p,
1989 "Returns true if the target supports fixed-point arithmetic.",
1991 default_fixed_point_supported_p)
1993 /* Return true if anonymous bitfields affect structure alignment. */
1995 (align_anon_bitfield,
1996 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
1997 whether unnamed bitfields affect the alignment of the containing\n\
1998 structure. The hook should return true if the structure should inherit\n\
1999 the alignment requirements of an unnamed bitfield's type.",
2001 hook_bool_void_false)
2003 /* Return true if volatile bitfields should use the narrowest type possible.
2004 Return false if they should use the container type. */
2006 (narrow_volatile_bitfield,
2007 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2008 should use the narrowest mode possible. It should return @code{false} if\n\
2009 these accesses should use the bitfield container type.\n\
2011 The default is @code{false}.",
2013 hook_bool_void_false)
2015 /* Set up target-specific built-in functions. */
2018 "Define this hook if you have any machine-specific built-in functions\n\
2019 that need to be defined. It should be a function that performs the\n\
2022 Machine specific built-in functions can be useful to expand special machine\n\
2023 instructions that would otherwise not normally be generated because\n\
2024 they have no equivalent in the source language (for example, SIMD vector\n\
2025 instructions or prefetch instructions).\n\
2027 To create a built-in function, call the function\n\
2028 @code{lang_hooks.builtin_function}\n\
2029 which is defined by the language front end. You can use any type nodes set\n\
2030 up by @code{build_common_tree_nodes};\n\
2031 only language front ends that use those two functions will call\n\
2032 @samp{TARGET_INIT_BUILTINS}.",
2036 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2037 built-in function decl for CODE.
2038 Return NULL if that is not possible. Return error_mark_node if CODE
2039 is outside of the range of valid target builtin function codes. */
2042 "Define this hook if you have any machine-specific built-in functions\n\
2043 that need to be defined. It should be a function that returns the\n\
2044 builtin function declaration for the builtin function code @var{code}.\n\
2045 If there is no such builtin and it cannot be initialized at this time\n\
2046 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2047 If @var{code} is out of range the function should return\n\
2048 @code{error_mark_node}.",
2049 tree, (unsigned code, bool initialize_p), NULL)
2051 /* Expand a target-specific builtin. */
2055 Expand a call to a machine specific built-in function that was set up by\n\
2056 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2057 function call; the result should go to @var{target} if that is\n\
2058 convenient, and have mode @var{mode} if that is convenient.\n\
2059 @var{subtarget} may be used as the target for computing one of\n\
2060 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2061 ignored. This function should return the result of the call to the\n\
2062 built-in function.",
2064 (tree exp, rtx target, rtx subtarget, enum machine_mode mode, int ignore),
2065 default_expand_builtin)
2067 /* Select a replacement for a target-specific builtin. This is done
2068 *before* regular type checking, and so allows the target to
2069 implement a crude form of function overloading. The result is a
2070 complete expression that implements the operation. PARAMS really
2071 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2073 (resolve_overloaded_builtin,
2074 "Select a replacement for a machine specific built-in function that\n\
2075 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2076 @emph{before} regular type checking, and so allows the target to\n\
2077 implement a crude form of function overloading. @var{fndecl} is the\n\
2078 declaration of the built-in function. @var{arglist} is the list of\n\
2079 arguments passed to the built-in function. The result is a\n\
2080 complete expression that implements the operation, usually\n\
2081 another @code{CALL_EXPR}.\n\
2082 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2083 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2085 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2089 "Fold a call to a machine specific built-in function that was set up by\n\
2090 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2091 built-in function. @var{n_args} is the number of arguments passed to\n\
2092 the function; the arguments themselves are pointed to by @var{argp}.\n\
2093 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2094 containing a simplified expression for the call's result. If\n\
2095 @var{ignore} is true the value will be ignored.",
2096 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2097 hook_tree_tree_int_treep_bool_null)
2099 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2101 (gimple_fold_builtin,
2102 "Fold a call to a machine specific built-in function that was set up\n\
2103 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2104 statement holding the function call. Returns true if any change\n\
2105 was made to the GIMPLE stream.",
2106 bool, (gimple_stmt_iterator *gsi),
2107 hook_bool_gsiptr_false)
2109 /* Target hook is used to compare the target attributes in two functions to
2110 determine which function's features get higher priority. This is used
2111 during function multi-versioning to figure out the order in which two
2112 versions must be dispatched. A function version with a higher priority
2113 is checked for dispatching earlier. DECL1 and DECL2 are
2114 the two function decls that will be compared. It returns positive value
2115 if DECL1 is higher priority, negative value if DECL2 is higher priority
2116 and 0 if they are the same. */
2118 (compare_version_priority,
2119 "This hook is used to compare the target attributes in two functions to\n\
2120 determine which function's features get higher priority. This is used\n\
2121 during function multi-versioning to figure out the order in which two\n\
2122 versions must be dispatched. A function version with a higher priority\n\
2123 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2124 the two function decls that will be compared.",
2125 int, (tree decl1, tree decl2), NULL)
2127 /* Target hook is used to generate the dispatcher logic to invoke the right
2128 function version at run-time for a given set of function versions.
2129 ARG points to the callgraph node of the dispatcher function whose body
2130 must be generated. */
2132 (generate_version_dispatcher_body,
2133 "This hook is used to generate the dispatcher logic to invoke the right\n\
2134 function version at run-time for a given set of function versions.\n\
2135 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2136 body must be generated.",
2137 tree, (void *arg), NULL)
2139 /* Target hook is used to get the dispatcher function for a set of function
2140 versions. The dispatcher function is called to invoke the right function
2141 version at run-time. DECL is one version from a set of semantically
2142 identical versions. */
2144 (get_function_versions_dispatcher,
2145 "This hook is used to get the dispatcher function for a set of function\n\
2146 versions. The dispatcher function is called to invoke the right function\n\
2147 version at run-time. @var{decl} is one version from a set of semantically\n\
2148 identical versions.",
2149 tree, (void *decl), NULL)
2151 /* Returns a code for a target-specific builtin that implements
2152 reciprocal of the function, or NULL_TREE if not available. */
2154 (builtin_reciprocal,
2155 "This hook should return the DECL of a function that implements reciprocal of\n\
2156 the builtin function with builtin function code @var{fn}, or\n\
2157 @code{NULL_TREE} if such a function is not available. @var{md_fn} is true\n\
2158 when @var{fn} is a code of a machine-dependent builtin function. When\n\
2159 @var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2160 of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2161 function are valid.",
2162 tree, (unsigned fn, bool md_fn, bool sqrt),
2163 default_builtin_reciprocal)
2165 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2166 string containing the C++ mangling for TYPE. In all other cases, return
2170 "If your target defines any fundamental types, or any types your target\n\
2171 uses should be mangled differently from the default, define this hook\n\
2172 to return the appropriate encoding for these types as part of a C++\n\
2173 mangled name. The @var{type} argument is the tree structure representing\n\
2174 the type to be mangled. The hook may be applied to trees which are\n\
2175 not target-specific fundamental types; it should return @code{NULL}\n\
2176 for all such types, as well as arguments it does not recognize. If the\n\
2177 return value is not @code{NULL}, it must point to a statically-allocated\n\
2180 Target-specific fundamental types might be new fundamental types or\n\
2181 qualified versions of ordinary fundamental types. Encode new\n\
2182 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2183 is the name used for the type in source code, and @var{n} is the\n\
2184 length of @var{name} in decimal. Encode qualified versions of\n\
2185 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2186 @var{name} is the name used for the type qualifier in source code,\n\
2187 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2188 code used to represent the unqualified version of this type. (See\n\
2189 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2190 codes.) In both cases the spaces are for clarity; do not include any\n\
2191 spaces in your string.\n\
2193 This hook is applied to types prior to typedef resolution. If the mangled\n\
2194 name for a particular type depends only on that type's main variant, you\n\
2195 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2198 The default version of this hook always returns @code{NULL}, which is\n\
2199 appropriate for a target that does not define any new fundamental\n\
2201 const char *, (const_tree type),
2202 hook_constcharptr_const_tree_null)
2204 /* Make any adjustments to libfunc names needed for this target. */
2207 "This hook should declare additional library routines or rename\n\
2208 existing ones, using the functions @code{set_optab_libfunc} and\n\
2209 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2210 @code{init_optabs} calls this macro after initializing all the normal\n\
2211 library routines.\n\
2213 The default is to do nothing. Most ports don't need to define this hook.",
2217 /* Add a __gnu_ prefix to library functions rather than just __. */
2219 (libfunc_gnu_prefix,
2220 "If false (the default), internal library routines start with two\n\
2221 underscores. If set to true, these routines start with @code{__gnu_}\n\
2222 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2223 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2224 is set to true, the @file{tm.h} file must also\n\
2225 @code{#define LIBGCC2_GNU_PREFIX}.",
2228 /* Given a decl, a section name, and whether the decl initializer
2229 has relocs, choose attributes for the section. */
2230 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2232 (section_type_flags,
2233 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2234 based on a variable or function decl, a section name, and whether or not the\n\
2235 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2236 null, in which case read-write data should be assumed.\n\
2238 The default version of this function handles choosing code vs data,\n\
2239 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2240 need to override this if your target has special flags that might be\n\
2241 set via @code{__attribute__}.",
2242 unsigned int, (tree decl, const char *name, int reloc),
2243 default_section_type_flags)
2247 "This hook determines whether a function from a class of functions\n\
2248 @var{fn_class} is present at the runtime.",
2249 bool, (enum function_class fn_class),
2250 default_libc_has_function)
2252 /* True if new jumps cannot be created, to replace existing ones or
2253 not, at the current point in the compilation. */
2255 (cannot_modify_jumps_p,
2256 "This target hook returns @code{true} past the point in which new jump\n\
2257 instructions could be created. On machines that require a register for\n\
2258 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2259 reload, so this target hook should be defined to a function such as:\n\
2263 cannot_modify_jumps_past_reload_p ()\n\
2265 return (reload_completed || reload_in_progress);\n\
2269 hook_bool_void_false)
2271 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2274 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2275 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2276 false, if it can't.\
2277 For example, on some targets, certain kinds of branches can't be made to\
2278 follow through a hot/cold partitioning.",
2279 bool, (const_rtx follower, const_rtx followee),
2280 hook_bool_const_rtx_const_rtx_true)
2282 /* Return a register class for which branch target register
2283 optimizations should be applied. */
2285 (branch_target_register_class,
2286 "This target hook returns a register class for which branch target register\n\
2287 optimizations should be applied. All registers in this class should be\n\
2288 usable interchangeably. After reload, registers in this class will be\n\
2289 re-allocated and loads will be hoisted out of loops and be subjected\n\
2290 to inter-block scheduling.",
2291 reg_class_t, (void),
2292 default_branch_target_register_class)
2294 /* Return true if branch target register optimizations should include
2295 callee-saved registers that are not already live during the current
2296 function. AFTER_PE_GEN is true if prologues and epilogues have
2297 already been generated. */
2299 (branch_target_register_callee_saved,
2300 "Branch target register optimization will by default exclude callee-saved\n\
2302 that are not already live during the current function; if this target hook\n\
2303 returns true, they will be included. The target code must than make sure\n\
2304 that all target registers in the class returned by\n\
2305 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2306 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2307 epilogues have already been generated. Note, even if you only return\n\
2308 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2309 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2310 to reserve space for caller-saved target registers.",
2311 bool, (bool after_prologue_epilogue_gen),
2312 hook_bool_bool_false)
2314 /* Return true if the target supports conditional execution. */
2316 (have_conditional_execution,
2317 "This target hook returns true if the target supports conditional execution.\n\
2318 This target hook is required only when the target has several different\n\
2319 modes and they have different conditional execution capability, such as ARM.",
2321 default_have_conditional_execution)
2323 /* Return a new value for loop unroll size. */
2325 (loop_unroll_adjust,
2326 "This target hook returns a new value for the number of times @var{loop}\n\
2327 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2328 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2329 the loop, which is going to be checked for unrolling. This target hook\n\
2330 is required only when the target has special constraints like maximum\n\
2331 number of memory accesses.",
2332 unsigned, (unsigned nunroll, struct loop *loop),
2335 /* True if X is a legitimate MODE-mode immediate operand. */
2337 (legitimate_constant_p,
2338 "This hook returns true if @var{x} is a legitimate constant for a\n\
2339 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2340 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2342 The default definition returns true.",
2343 bool, (enum machine_mode mode, rtx x),
2344 hook_bool_mode_rtx_true)
2346 /* True if the constant X cannot be placed in the constant pool. */
2348 (cannot_force_const_mem,
2349 "This hook should return true if @var{x} is of a form that cannot (or\n\
2350 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2353 The default version of this hook returns false.\n\
2355 The primary reason to define this hook is to prevent reload from\n\
2356 deciding that a non-legitimate constant would be better reloaded\n\
2357 from the constant pool instead of spilling and reloading a register\n\
2358 holding the constant. This restriction is often true of addresses\n\
2359 of TLS symbols for various targets.",
2360 bool, (enum machine_mode mode, rtx x),
2361 hook_bool_mode_rtx_false)
2364 (cannot_copy_insn_p,
2365 "True if the insn @var{x} cannot be duplicated.",
2368 /* True if X is considered to be commutative. */
2371 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2372 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2373 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2374 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2375 bool, (const_rtx x, int outer_code),
2376 hook_bool_const_rtx_commutative_p)
2378 /* True if ADDR is an address-expression whose effect depends
2379 on the mode of the memory reference it is used in. */
2381 (mode_dependent_address_p,
2382 "This hook returns @code{true} if memory address @var{addr} in address\n\
2383 space @var{addrspace} can have\n\
2384 different meanings depending on the machine mode of the memory\n\
2385 reference it is used for or if the address is valid for some modes\n\
2388 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2389 effects because the amount of the increment or decrement is the size\n\
2390 of the operand being addressed. Some machines have other mode-dependent\n\
2391 addresses. Many RISC machines have no mode-dependent addresses.\n\
2393 You may assume that @var{addr} is a valid address for the machine.\n\
2395 The default version of this hook returns @code{false}.",
2396 bool, (const_rtx addr, addr_space_t addrspace),
2397 default_mode_dependent_address_p)
2399 /* Given an invalid address X for a given machine mode, try machine-specific
2400 ways to make it legitimate. Return X or an invalid address on failure. */
2402 (legitimize_address,
2403 "This hook is given an invalid memory address @var{x} for an\n\
2404 operand of mode @var{mode} and should try to return a valid memory\n\
2407 @findex break_out_memory_refs\n\
2408 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2409 and @var{oldx} will be the operand that was given to that function to produce\n\
2412 The code of the hook should not alter the substructure of\n\
2413 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2414 should return the new @var{x}.\n\
2416 It is not necessary for this hook to come up with a legitimate address,\n\
2417 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2418 The compiler has standard ways of doing so in all cases. In fact, if\n\
2419 the target supports only emulated TLS, it\n\
2420 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2421 a valid way to legitimize the address. But often a machine-dependent\n\
2422 strategy can generate better code.",
2423 rtx, (rtx x, rtx oldx, enum machine_mode mode),
2424 default_legitimize_address)
2426 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2428 (delegitimize_address,
2429 "This hook is used to undo the possibly obfuscating effects of the\n\
2430 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2431 macros. Some backend implementations of these macros wrap symbol\n\
2432 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2433 addressing modes. This target hook allows GCC's optimizers to understand\n\
2434 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2435 into their original form.",
2437 delegitimize_mem_from_attrs)
2439 /* Given an RTX, return true if it is not ok to emit it into debug info
2442 (const_not_ok_for_debug_p,
2443 "This hook should return true if @var{x} should not be emitted into\n\
2446 hook_bool_rtx_false)
2448 /* Given an address RTX, say whether it is valid. */
2450 (legitimate_address_p,
2451 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2452 address on the target machine for a memory operand of mode @var{mode}.\n\
2454 Legitimate addresses are defined in two variants: a strict variant and a\n\
2455 non-strict one. The @var{strict} parameter chooses which variant is\n\
2456 desired by the caller.\n\
2458 The strict variant is used in the reload pass. It must be defined so\n\
2459 that any pseudo-register that has not been allocated a hard register is\n\
2460 considered a memory reference. This is because in contexts where some\n\
2461 kind of register is required, a pseudo-register with no hard register\n\
2462 must be rejected. For non-hard registers, the strict variant should look\n\
2463 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2464 register number in the array, or treat the pseudo as a memory reference\n\
2465 if the array holds @code{-1}.\n\
2467 The non-strict variant is used in other passes. It must be defined to\n\
2468 accept all pseudo-registers in every context where some kind of\n\
2469 register is required.\n\
2471 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2472 and an integer are stored inside a @code{const} RTX to mark them as\n\
2473 constant. Therefore, there is no need to recognize such sums\n\
2474 specifically as legitimate addresses. Normally you would simply\n\
2475 recognize any @code{const} as legitimate.\n\
2477 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2478 sums that are not marked with @code{const}. It assumes that a naked\n\
2479 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2480 naked constant sums as illegitimate addresses, so that none of them will\n\
2481 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2483 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2484 On some machines, whether a symbolic address is legitimate depends on\n\
2485 the section that the address refers to. On these machines, define the\n\
2486 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2487 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2488 @code{const}, you will have to look inside it to find the\n\
2489 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2492 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2493 Some ports are still using a deprecated legacy substitute for\n\
2494 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2498 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2502 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2503 address on the target machine for a memory operand of mode @var{mode}.\n\
2505 @findex REG_OK_STRICT\n\
2506 Compiler source files that want to use the strict variant of this\n\
2507 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2508 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2509 that case and the non-strict variant otherwise.\n\
2511 Using the hook is usually simpler because it limits the number of\n\
2512 files that are recompiled when changes are made.",
2513 bool, (enum machine_mode mode, rtx x, bool strict),
2514 default_legitimate_address_p)
2516 /* True if the given constant can be put into an object_block. */
2518 (use_blocks_for_constant_p,
2519 "This hook should return true if pool entries for constant @var{x} can\n\
2520 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2523 The default version returns false for all constants.",
2524 bool, (enum machine_mode mode, const_rtx x),
2525 hook_bool_mode_const_rtx_false)
2527 /* True if the given decl can be put into an object_block. */
2529 (use_blocks_for_decl_p,
2530 "This hook should return true if pool entries for @var{decl} should\n\
2531 be placed in an @code{object_block} structure.\n\
2533 The default version returns true for all decls.",
2534 bool, (const_tree decl),
2535 hook_bool_const_tree_true)
2537 /* The minimum and maximum byte offsets for anchored addresses. */
2540 "The minimum offset that should be applied to a section anchor.\n\
2541 On most targets, it should be the smallest offset that can be\n\
2542 applied to a base register while still giving a legitimate address\n\
2543 for every mode. The default value is 0.",
2548 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2549 offset that should be applied to section anchors. The default\n\
2553 /* True if section anchors can be used to access the given symbol. */
2555 (use_anchors_for_symbol_p,
2556 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2557 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2558 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2560 The default version is correct for most targets, but you might need to\n\
2561 intercept this hook to handle things like target-specific attributes\n\
2562 or target-specific sections.",
2563 bool, (const_rtx x),
2564 default_use_anchors_for_symbol_p)
2566 /* True if target supports indirect functions. */
2569 "It returns true if the target supports GNU indirect functions.\n\
2570 The support includes the assembler, linker and dynamic linker.\n\
2571 The default value of this hook is based on target's libc.",
2573 default_has_ifunc_p)
2575 /* True if it is OK to do sibling call optimization for the specified
2576 call expression EXP. DECL will be the called function, or NULL if
2577 this is an indirect call. */
2579 (function_ok_for_sibcall,
2580 "True if it is OK to do sibling call optimization for the specified\n\
2581 call expression @var{exp}. @var{decl} will be the called function,\n\
2582 or @code{NULL} if this is an indirect call.\n\
2584 It is not uncommon for limitations of calling conventions to prevent\n\
2585 tail calls to functions outside the current unit of translation, or\n\
2586 during PIC compilation. The hook is used to enforce these restrictions,\n\
2587 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2588 ``normal'' call. The criteria for successful sibling call optimization\n\
2589 may vary greatly between different architectures.",
2590 bool, (tree decl, tree exp),
2591 hook_bool_tree_tree_false)
2593 /* Establish appropriate back-end context for processing the function
2594 FNDECL. The argument might be NULL to indicate processing at top
2595 level, outside of any function scope. */
2597 (set_current_function,
2598 "The compiler invokes this hook whenever it changes its current function\n\
2599 context (@code{cfun}). You can define this function if\n\
2600 the back end needs to perform any initialization or reset actions on a\n\
2601 per-function basis. For example, it may be used to implement function\n\
2602 attributes that affect register usage or code generation patterns.\n\
2603 The argument @var{decl} is the declaration for the new function context,\n\
2604 and may be null to indicate that the compiler has left a function context\n\
2605 and is returning to processing at the top level.\n\
2606 The default hook function does nothing.\n\
2608 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2609 some parts of the back end. The hook function is not invoked in this\n\
2610 situation; you need not worry about the hook being invoked recursively,\n\
2611 or when the back end is in a partially-initialized state.\n\
2612 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2613 outside of any function scope.",
2614 void, (tree decl), hook_void_tree)
2616 /* True if EXP should be placed in a "small data" section. */
2619 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2620 The default version of this hook always returns false.",
2621 bool, (const_tree exp),
2622 hook_bool_const_tree_false)
2624 /* True if EXP names an object for which name resolution must resolve
2625 to the current executable or shared library. */
2628 "Returns true if @var{exp} names an object for which name resolution\n\
2629 rules must resolve to the current ``module'' (dynamic shared library\n\
2630 or executable image).\n\
2632 The default version of this hook implements the name resolution rules\n\
2633 for ELF, which has a looser model of global name binding than other\n\
2634 currently supported object file formats.",
2635 bool, (const_tree exp),
2636 default_binds_local_p)
2638 /* Check if profiling code is before or after prologue. */
2640 (profile_before_prologue,
2641 "It returns true if target wants profile code emitted before prologue.\n\n\
2642 The default version of this hook use the target macro\n\
2643 @code{PROFILE_BEFORE_PROLOGUE}.",
2645 default_profile_before_prologue)
2647 /* Return true if a leaf function should stay leaf even with profiling
2650 (keep_leaf_when_profiled,
2651 "This target hook returns true if the target wants the leaf flag for\
2652 the current function to stay true even if it calls mcount. This might\
2653 make sense for targets using the leaf flag only to determine whether a\
2654 stack frame needs to be generated or not and for which the call to\
2655 mcount is generated before the function prologue.",
2657 default_keep_leaf_when_profiled)
2659 /* Modify and return the identifier of a DECL's external name,
2660 originally identified by ID, as required by the target,
2661 (eg, append @nn to windows32 stdcall function names).
2662 The default is to return ID without modification. */
2664 (mangle_decl_assembler_name,
2665 "Define this hook if you need to postprocess the assembler name generated\n\
2666 by target-independent code. The @var{id} provided to this hook will be\n\
2667 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2668 or the mangled name of the @var{decl} in C++). The return value of the\n\
2669 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2670 your target system. The default implementation of this hook just\n\
2671 returns the @var{id} provided.",
2672 tree, (tree decl, tree id),
2673 default_mangle_decl_assembler_name)
2675 /* Do something target-specific to record properties of the DECL into
2676 the associated SYMBOL_REF. */
2678 (encode_section_info,
2679 "Define this hook if references to a symbol or a constant must be\n\
2680 treated differently depending on something about the variable or\n\
2681 function named by the symbol (such as what section it is in).\n\
2683 The hook is executed immediately after rtl has been created for\n\
2684 @var{decl}, which may be a variable or function declaration or\n\
2685 an entry in the constant pool. In either case, @var{rtl} is the\n\
2686 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
2687 in this hook; that field may not have been initialized yet.\n\
2689 In the case of a constant, it is safe to assume that the rtl is\n\
2690 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
2691 will also have this form, but that is not guaranteed. Global\n\
2692 register variables, for instance, will have a @code{reg} for their\n\
2693 rtl. (Normally the right thing to do with such unusual rtl is\n\
2696 The @var{new_decl_p} argument will be true if this is the first time\n\
2697 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
2698 be false for subsequent invocations, which will happen for duplicate\n\
2699 declarations. Whether or not anything must be done for the duplicate\n\
2700 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
2701 @var{new_decl_p} is always true when the hook is called for a constant.\n\
2703 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
2704 The usual thing for this hook to do is to record flags in the\n\
2705 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
2706 Historically, the name string was modified if it was necessary to\n\
2707 encode more than one bit of information, but this practice is now\n\
2708 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
2710 The default definition of this hook, @code{default_encode_section_info}\n\
2711 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
2712 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
2713 before overriding it.",
2714 void, (tree decl, rtx rtl, int new_decl_p),
2715 default_encode_section_info)
2717 /* Undo the effects of encode_section_info on the symbol string. */
2719 (strip_name_encoding,
2720 "Decode @var{name} and return the real name part, sans\n\
2721 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
2723 const char *, (const char *name),
2724 default_strip_name_encoding)
2726 /* If shift optabs for MODE are known to always truncate the shift count,
2727 return the mask that they apply. Return 0 otherwise. */
2729 (shift_truncation_mask,
2730 "This function describes how the standard shift patterns for @var{mode}\n\
2731 deal with shifts by negative amounts or by more than the width of the mode.\n\
2732 @xref{shift patterns}.\n\
2734 On many machines, the shift patterns will apply a mask @var{m} to the\n\
2735 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
2736 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
2737 this is true for mode @var{mode}, the function should return @var{m},\n\
2738 otherwise it should return 0. A return value of 0 indicates that no\n\
2739 particular behavior is guaranteed.\n\
2741 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
2742 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
2743 that are generated by the named shift patterns.\n\
2745 The default implementation of this function returns\n\
2746 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
2747 and 0 otherwise. This definition is always safe, but if\n\
2748 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
2749 nevertheless truncate the shift count, you may get better code\n\
2751 unsigned HOST_WIDE_INT, (enum machine_mode mode),
2752 default_shift_truncation_mask)
2754 /* Return the number of divisions in the given MODE that should be present,
2755 so that it is profitable to turn the division into a multiplication by
2758 (min_divisions_for_recip_mul,
2759 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
2760 divisions by the same divisor, by turning them into multiplications by\n\
2761 the reciprocal. This target hook specifies the minimum number of divisions\n\
2762 that should be there for GCC to perform the optimization for a variable\n\
2763 of mode @var{mode}. The default implementation returns 3 if the machine\n\
2764 has an instruction for the division, and 2 if it does not.",
2765 unsigned int, (enum machine_mode mode),
2766 default_min_divisions_for_recip_mul)
2768 /* If the representation of integral MODE is such that values are
2769 always sign-extended to a wider mode MODE_REP then return
2770 SIGN_EXTEND. Return UNKNOWN otherwise. */
2771 /* Note that the return type ought to be RTX_CODE, but that's not
2772 necessarily defined at this point. */
2775 "The representation of an integral mode can be such that the values\n\
2776 are always extended to a wider integral mode. Return\n\
2777 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
2778 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
2779 otherwise. (Currently, none of the targets use zero-extended\n\
2780 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
2781 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
2782 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
2783 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
2784 widest integral mode and currently we take advantage of this fact.)\n\
2786 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
2787 value even if the extension is not performed on certain hard registers\n\
2788 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
2789 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
2791 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
2792 describe two related properties. If you define\n\
2793 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
2794 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
2797 In order to enforce the representation of @code{mode},\n\
2798 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
2800 int, (enum machine_mode mode, enum machine_mode rep_mode),
2801 default_mode_rep_extended)
2803 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
2805 (valid_pointer_mode,
2806 "Define this to return nonzero if the port can handle pointers\n\
2807 with machine mode @var{mode}. The default version of this\n\
2808 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
2809 bool, (enum machine_mode mode),
2810 default_valid_pointer_mode)
2812 /* Disambiguate with errno. */
2814 (ref_may_alias_errno,
2815 "Define this to return nonzero if the memory reference @var{ref}\
2816 may alias with the system C library errno location. The default\
2817 version of this hook assumes the system C library errno location\
2818 is either a declaration of type int or accessed by dereferencing\
2820 bool, (struct ao_ref *ref),
2821 default_ref_may_alias_errno)
2823 /* Support for named address spaces. */
2825 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
2826 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
2828 /* MODE to use for a pointer into another address space. */
2831 "Define this to return the machine mode to use for pointers to\n\
2832 @var{address_space} if the target supports named address spaces.\n\
2833 The default version of this hook returns @code{ptr_mode} for the\n\
2834 generic address space only.",
2835 enum machine_mode, (addr_space_t address_space),
2836 default_addr_space_pointer_mode)
2838 /* MODE to use for an address in another address space. */
2841 "Define this to return the machine mode to use for addresses in\n\
2842 @var{address_space} if the target supports named address spaces.\n\
2843 The default version of this hook returns @code{Pmode} for the\n\
2844 generic address space only.",
2845 enum machine_mode, (addr_space_t address_space),
2846 default_addr_space_address_mode)
2848 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
2849 in another address space. */
2851 (valid_pointer_mode,
2852 "Define this to return nonzero if the port can handle pointers\n\
2853 with machine mode @var{mode} to address space @var{as}. This target\n\
2854 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
2855 except that it includes explicit named address space support. The default\n\
2856 version of this hook returns true for the modes returned by either the\n\
2857 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
2858 target hooks for the given address space.",
2859 bool, (enum machine_mode mode, addr_space_t as),
2860 default_addr_space_valid_pointer_mode)
2862 /* True if an address is a valid memory address to a given named address
2863 space for a given mode. */
2865 (legitimate_address_p,
2866 "Define this to return true if @var{exp} is a valid address for mode\n\
2867 @var{mode} in the named address space @var{as}. The @var{strict}\n\
2868 parameter says whether strict addressing is in effect after reload has\n\
2869 finished. This target hook is the same as the\n\
2870 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
2871 explicit named address space support.",
2872 bool, (enum machine_mode mode, rtx exp, bool strict, addr_space_t as),
2873 default_addr_space_legitimate_address_p)
2875 /* Return an updated address to convert an invalid pointer to a named
2876 address space to a valid one. If NULL_RTX is returned use machine
2877 independent methods to make the address valid. */
2879 (legitimize_address,
2880 "Define this to modify an invalid address @var{x} to be a valid address\n\
2881 with mode @var{mode} in the named address space @var{as}. This target\n\
2882 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
2883 except that it includes explicit named address space support.",
2884 rtx, (rtx x, rtx oldx, enum machine_mode mode, addr_space_t as),
2885 default_addr_space_legitimize_address)
2887 /* True if one named address space is a subset of another named address. */
2890 "Define this to return whether the @var{subset} named address space is\n\
2891 contained within the @var{superset} named address space. Pointers to\n\
2892 a named address space that is a subset of another named address space\n\
2893 will be converted automatically without a cast if used together in\n\
2894 arithmetic operations. Pointers to a superset address space can be\n\
2895 converted to pointers to a subset address space via explicit casts.",
2896 bool, (addr_space_t subset, addr_space_t superset),
2897 default_addr_space_subset_p)
2899 /* Function to convert an rtl expression from one address space to another. */
2902 "Define this to convert the pointer expression represented by the RTL\n\
2903 @var{op} with type @var{from_type} that points to a named address\n\
2904 space to a new pointer expression with type @var{to_type} that points\n\
2905 to a different named address space. When this hook it called, it is\n\
2906 guaranteed that one of the two address spaces is a subset of the other,\n\
2907 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
2908 rtx, (rtx op, tree from_type, tree to_type),
2909 default_addr_space_convert)
2911 HOOK_VECTOR_END (addr_space)
2914 #define HOOK_PREFIX "TARGET_"
2916 /* True if MODE is valid for the target. By "valid", we mean able to
2917 be manipulated in non-trivial ways. In particular, this means all
2918 the arithmetic is supported. */
2920 (scalar_mode_supported_p,
2921 "Define this to return nonzero if the port is prepared to handle\n\
2922 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
2923 considered supported, all the basic arithmetic and comparisons\n\
2926 The default version of this hook returns true for any mode\n\
2927 required to handle the basic C types (as defined by the port).\n\
2928 Included here are the double-word arithmetic supported by the\n\
2929 code in @file{optabs.c}.",
2930 bool, (enum machine_mode mode),
2931 default_scalar_mode_supported_p)
2933 /* Similarly for vector modes. "Supported" here is less strict. At
2934 least some operations are supported; need to check optabs or builtins
2935 for further details. */
2937 (vector_mode_supported_p,
2938 "Define this to return nonzero if the port is prepared to handle\n\
2939 insns involving vector mode @var{mode}. At the very least, it\n\
2940 must have move patterns for this mode.",
2941 bool, (enum machine_mode mode),
2942 hook_bool_mode_false)
2946 "This hook can be used to define the alignment for a vector of type\n\
2947 @var{type}, in order to comply with a platform ABI. The default is to\n\
2948 require natural alignment for vector types. The alignment returned by\n\
2949 this hook must be a power-of-two multiple of the default alignment of\n\
2950 the vector element type.",
2951 HOST_WIDE_INT, (const_tree type),
2952 default_vector_alignment)
2954 /* True if we should try to use a scalar mode to represent an array,
2955 overriding the usual MAX_FIXED_MODE limit. */
2957 (array_mode_supported_p,
2958 "Return true if GCC should try to use a scalar mode to store an array\n\
2959 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
2960 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
2961 and allows GCC to use any defined integer mode.\n\
2963 One use of this hook is to support vector load and store operations\n\
2964 that operate on several homogeneous vectors. For example, ARM NEON\n\
2965 has operations like:\n\
2968 int8x8x3_t vld3_s8 (const int8_t *)\n\
2969 @end smallexample\n\
2971 where the return type is defined as:\n\
2974 typedef struct int8x8x3_t\n\
2978 @end smallexample\n\
2980 If this hook allows @code{val} to have a scalar mode, then\n\
2981 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
2982 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
2983 bool, (enum machine_mode mode, unsigned HOST_WIDE_INT nelems),
2984 hook_bool_mode_uhwi_false)
2986 /* Compute cost of moving data from a register of class FROM to one of
2989 (register_move_cost,
2990 "This target hook should return the cost of moving data of mode @var{mode}\n\
2991 from a register in class @var{from} to one in class @var{to}. The classes\n\
2992 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
2993 A value of 2 is the default; other values are interpreted relative to\n\
2996 It is not required that the cost always equal 2 when @var{from} is the\n\
2997 same as @var{to}; on some machines it is expensive to move between\n\
2998 registers if they are not general registers.\n\
3000 If reload sees an insn consisting of a single @code{set} between two\n\
3001 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3002 classes returns a value of 2, reload does not check to ensure that the\n\
3003 constraints of the insn are met. Setting a cost of other than 2 will\n\
3004 allow reload to verify that the constraints are met. You should do this\n\
3005 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3007 The default version of this function returns 2.",
3008 int, (enum machine_mode mode, reg_class_t from, reg_class_t to),
3009 default_register_move_cost)
3011 /* Compute cost of moving registers to/from memory. */
3012 /* ??? Documenting the argument types for this hook requires a GFDL
3013 license grant. Also, the documentation uses a different name for RCLASS. */
3016 "This target hook should return the cost of moving data of mode @var{mode}\n\
3017 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3018 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3019 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3020 If moving between registers and memory is more expensive than between two\n\
3021 registers, you should add this target hook to express the relative cost.\n\
3023 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3024 the cost of copying via a secondary reload register, if one is\n\
3025 needed. If your machine requires a secondary reload register to copy\n\
3026 between memory and a register of @var{rclass} but the reload mechanism is\n\
3027 more complex than copying via an intermediate, use this target hook to\n\
3028 reflect the actual cost of the move.\n\
3030 GCC defines the function @code{memory_move_secondary_cost} if\n\
3031 secondary reloads are needed. It computes the costs due to copying via\n\
3032 a secondary register. If your machine copies from memory using a\n\
3033 secondary register in the conventional way but the default base value of\n\
3034 4 is not correct for your machine, use this target hook to add some other\n\
3035 value to the result of that function. The arguments to that function\n\
3036 are the same as to this target hook.",
3037 int, (enum machine_mode mode, reg_class_t rclass, bool in),
3038 default_memory_move_cost)
3040 /* True for MODE if the target expects that registers in this mode will
3041 be allocated to registers in a small register class. The compiler is
3042 allowed to use registers explicitly used in the rtl as spill registers
3043 but it should prevent extending the lifetime of these registers. */
3045 (small_register_classes_for_mode_p,
3046 "Define this to return nonzero for machine modes for which the port has\n\
3047 small register classes. If this target hook returns nonzero for a given\n\
3048 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3049 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3050 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3053 On some machines, it is risky to let hard registers live across arbitrary\n\
3054 insns. Typically, these machines have instructions that require values\n\
3055 to be in specific registers (like an accumulator), and reload will fail\n\
3056 if the required hard register is used for another purpose across such an\n\
3059 Passes before reload do not know which hard registers will be used\n\
3060 in an instruction, but the machine modes of the registers set or used in\n\
3061 the instruction are already known. And for some machines, register\n\
3062 classes are small for, say, integer registers but not for floating point\n\
3063 registers. For example, the AMD x86-64 architecture requires specific\n\
3064 registers for the legacy x86 integer instructions, but there are many\n\
3065 SSE registers for floating point operations. On such targets, a good\n\
3066 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3067 machine modes but zero for the SSE register classes.\n\
3069 The default version of this hook returns false for any mode. It is always\n\
3070 safe to redefine this hook to return with a nonzero value. But if you\n\
3071 unnecessarily define it, you will reduce the amount of optimizations\n\
3072 that can be performed in some cases. If you do not define this hook\n\
3073 to return a nonzero value when it is required, the compiler will run out\n\
3074 of spill registers and print a fatal error message.",
3075 bool, (enum machine_mode mode),
3076 hook_bool_mode_false)
3078 /* Register number for a flags register. Only needs to be defined if the
3079 target is constrainted to use post-reload comparison elimination. */
3082 "If the target has a dedicated flags register, and it needs to use the\
3083 post-reload comparison elimination pass, then this value should be set\
3085 unsigned int, INVALID_REGNUM)
3087 /* Compute a (partial) cost for rtx X. Return true if the complete
3088 cost has been computed, and false if subexpressions should be
3089 scanned. In either case, *TOTAL contains the cost result. */
3090 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
3091 not necessarily defined at this point. */
3094 "This target hook describes the relative costs of RTL expressions.\n\
3096 The cost may depend on the precise form of the expression, which is\n\
3097 available for examination in @var{x}, and the fact that @var{x} appears\n\
3098 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3099 That is, the hook can assume that there is some rtx @var{y} such\n\
3100 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3101 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3102 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3104 @var{code} is @var{x}'s expression code---redundant, since it can be\n\
3105 obtained with @code{GET_CODE (@var{x})}.\n\
3107 In implementing this hook, you can use the construct\n\
3108 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3111 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3112 for the cost of the expression. The hook should modify this value as\n\
3113 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3114 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3115 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3117 When optimizing for code size, i.e.@: when @code{speed} is\n\
3118 false, this target hook should be used to estimate the relative\n\
3119 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3121 The hook returns true when all subexpressions of @var{x} have been\n\
3122 processed, and false when @code{rtx_cost} should recurse.",
3123 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
3124 hook_bool_rtx_int_int_int_intp_bool_false)
3126 /* Compute the cost of X, used as an address. Never called with
3127 invalid addresses. */
3130 "This hook computes the cost of an addressing mode that contains\n\
3131 @var{address}. If not defined, the cost is computed from\n\
3132 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3134 For most CISC machines, the default cost is a good approximation of the\n\
3135 true cost of the addressing mode. However, on RISC machines, all\n\
3136 instructions normally have the same length and execution time. Hence\n\
3137 all addresses will have equal costs.\n\
3139 In cases where more than one form of an address is known, the form with\n\
3140 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3141 cost, the one that is the most complex will be used.\n\
3143 For example, suppose an address that is equal to the sum of a register\n\
3144 and a constant is used twice in the same basic block. When this macro\n\
3145 is not defined, the address will be computed in a register and memory\n\
3146 references will be indirect through that register. On machines where\n\
3147 the cost of the addressing mode containing the sum is no higher than\n\
3148 that of a simple indirect reference, this will produce an additional\n\
3149 instruction and possibly require an additional register. Proper\n\
3150 specification of this macro eliminates this overhead for such machines.\n\
3152 This hook is never called with an invalid address.\n\
3154 On machines where an address involving more than one register is as\n\
3155 cheap as an address computation involving only one register, defining\n\
3156 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3157 be live over a region of code where only one would have been if\n\
3158 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3159 should be considered in the definition of this macro. Equivalent costs\n\
3160 should probably only be given to addresses with different numbers of\n\
3161 registers on machines with lots of registers.",
3162 int, (rtx address, enum machine_mode mode, addr_space_t as, bool speed),
3163 default_address_cost)
3165 /* Return where to allocate pseudo for a given hard register initial value. */
3167 (allocate_initial_value,
3169 When the initial value of a hard register has been copied in a pseudo\n\
3170 register, it is often not necessary to actually allocate another register\n\
3171 to this pseudo register, because the original hard register or a stack slot\n\
3172 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3173 is called at the start of register allocation once for each hard register\n\
3174 that had its initial value copied by using\n\
3175 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3176 Possible values are @code{NULL_RTX}, if you don't want\n\
3177 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3178 the hard register itself, if it is known not to be clobbered---or a\n\
3180 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3181 it might decide to use another register anyways.\n\
3182 You may use @code{current_function_is_leaf} or \n\
3183 @code{REG_N_SETS} in the hook to determine if the hard\n\
3184 register in question will not be clobbered.\n\
3185 The default value of this hook is @code{NULL}, which disables any special\n\
3187 rtx, (rtx hard_reg), NULL)
3189 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3190 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3193 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3194 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3195 this hook to enhance precision of analysis for @code{unspec} and\n\
3196 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3197 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3199 int, (const_rtx x, unsigned flags),
3200 default_unspec_may_trap_p)
3202 /* Given a register, this hook should return a parallel of registers
3203 to represent where to find the register pieces. Define this hook
3204 if the register and its mode are represented in Dwarf in
3205 non-contiguous locations, or if the register should be
3206 represented in more than one register in Dwarf. Otherwise, this
3207 hook should return NULL_RTX. */
3209 (dwarf_register_span,
3210 "Given a register, this hook should return a parallel of registers to\n\
3211 represent where to find the register pieces. Define this hook if the\n\
3212 register and its mode are represented in Dwarf in non-contiguous\n\
3213 locations, or if the register should be represented in more than one\n\
3214 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3215 If not defined, the default is to return @code{NULL_RTX}.",
3219 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3220 entries not corresponding directly to registers below
3221 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3222 code, given the address of the table. */
3224 (init_dwarf_reg_sizes_extra,
3225 "If some registers are represented in Dwarf-2 unwind information in\n\
3226 multiple pieces, define this hook to fill in information about the\n\
3227 sizes of those pieces in the table used by the unwinder at runtime.\n\
3228 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3229 filling in a single size corresponding to each hard register;\n\
3230 @var{address} is the address of the table.",
3231 void, (tree address),
3234 /* Fetch the fixed register(s) which hold condition codes, for
3235 targets where it makes sense to look for duplicate assignments to
3236 the condition codes. This should return true if there is such a
3237 register, false otherwise. The arguments should be set to the
3238 fixed register numbers. Up to two condition code registers are
3239 supported. If there is only one for this target, the int pointed
3240 at by the second argument should be set to -1. */
3242 (fixed_condition_code_regs,
3243 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3244 register rather than a pseudo-register to hold condition codes, the\n\
3245 regular CSE passes are often not able to identify cases in which the\n\
3246 hard register is set to a common value. Use this hook to enable a\n\
3247 small pass which optimizes such cases. This hook should return true\n\
3248 to enable this pass, and it should set the integers to which its\n\
3249 arguments point to the hard register numbers used for condition codes.\n\
3250 When there is only one such register, as is true on most systems, the\n\
3251 integer pointed to by @var{p2} should be set to\n\
3252 @code{INVALID_REGNUM}.\n\
3254 The default version of this hook returns false.",
3255 bool, (unsigned int *p1, unsigned int *p2),
3256 hook_bool_uintp_uintp_false)
3258 /* If two condition code modes are compatible, return a condition
3259 code mode which is compatible with both, such that a comparison
3260 done in the returned mode will work for both of the original
3261 modes. If the condition code modes are not compatible, return
3264 (cc_modes_compatible,
3265 "On targets which use multiple condition code modes in class\n\
3266 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3267 validly done in more than one mode. On such a system, define this\n\
3268 target hook to take two mode arguments and to return a mode in which\n\
3269 both comparisons may be validly done. If there is no such mode,\n\
3270 return @code{VOIDmode}.\n\
3272 The default version of this hook checks whether the modes are the\n\
3273 same. If they are, it returns that mode. If they are different, it\n\
3274 returns @code{VOIDmode}.",
3275 enum machine_mode, (enum machine_mode m1, enum machine_mode m2),
3276 default_cc_modes_compatible)
3278 /* Do machine-dependent code transformations. Called just before
3279 delayed-branch scheduling. */
3281 (machine_dependent_reorg,
3282 "If non-null, this hook performs a target-specific pass over the\n\
3283 instruction stream. The compiler will run it at all optimization levels,\n\
3284 just before the point at which it normally does delayed-branch scheduling.\n\
3286 The exact purpose of the hook varies from target to target. Some use\n\
3287 it to do transformations that are necessary for correctness, such as\n\
3288 laying out in-function constant pools or avoiding hardware hazards.\n\
3289 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3291 You need not implement the hook if it has nothing to do. The default\n\
3292 definition is null.",
3295 /* Create the __builtin_va_list type. */
3297 (build_builtin_va_list,
3298 "This hook returns a type node for @code{va_list} for the target.\n\
3299 The default version of the hook returns @code{void*}.",
3301 std_build_builtin_va_list)
3303 /* Enumerate the va list variants. */
3306 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3307 to iterate through the target specific builtin types for va_list. The\n\
3308 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3309 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3311 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3312 this macro and are set to the name of the va_list builtin type and its\n\
3314 If the return value of this macro is zero, then there is no more element.\n\
3315 Otherwise the @var{IDX} should be increased for the next call of this\n\
3316 macro to iterate through all types.",
3317 int, (int idx, const char **pname, tree *ptree),
3320 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3323 "This hook returns the va_list type of the calling convention specified by\n\
3325 The default version of this hook returns @code{va_list_type_node}.",
3326 tree, (tree fndecl),
3329 /* Get the __builtin_va_list type dependent on input type. */
3331 (canonical_va_list_type,
3332 "This hook returns the va_list type of the calling convention specified by the\n\
3333 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3336 std_canonical_va_list_type)
3338 /* ??? Documenting this hook requires a GFDL license grant. */
3340 (expand_builtin_va_start,
3341 "Expand the @code{__builtin_va_start} builtin.",
3342 void, (tree valist, rtx nextarg), NULL)
3344 /* Gimplifies a VA_ARG_EXPR. */
3346 (gimplify_va_arg_expr,
3347 "This hook performs target-specific gimplification of\n\
3348 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3349 arguments to @code{va_arg}; the latter two are as in\n\
3350 @code{gimplify.c:gimplify_expr}.",
3351 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3352 std_gimplify_va_arg_expr)
3354 /* Validity-checking routines for PCH files, target-specific.
3355 get_pch_validity returns a pointer to the data to be stored,
3356 and stores the size in its argument. pch_valid_p gets the same
3357 information back and returns NULL if the PCH is valid,
3358 or an error message if not. */
3361 "This hook returns a pointer to the data needed by\n\
3362 @code{TARGET_PCH_VALID_P} and sets\n\
3363 @samp{*@var{sz}} to the size of the data in bytes.",
3364 void *, (size_t *sz),
3365 default_get_pch_validity)
3369 "This hook checks whether the options used to create a PCH file are\n\
3370 compatible with the current settings. It returns @code{NULL}\n\
3371 if so and a suitable error message if not. Error messages will\n\
3372 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3374 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3375 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3376 It's safe to assume that the data was created by the same version of the\n\
3377 compiler, so no format checking is needed.\n\
3379 The default definition of @code{default_pch_valid_p} should be\n\
3380 suitable for most targets.",
3381 const char *, (const void *data, size_t sz),
3382 default_pch_valid_p)
3386 "Called before writing out a PCH file. If the target has some\n\
3387 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3388 it can use this hook to enforce that state. Very few targets need\n\
3389 to do anything here.",
3393 /* If nonnull, this function checks whether a PCH file with the
3394 given set of target flags can be used. It returns NULL if so,
3395 otherwise it returns an error message. */
3397 (check_pch_target_flags,
3398 "If this hook is nonnull, the default implementation of\n\
3399 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3400 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3401 @code{target_flags} had when the PCH file was created. The return\n\
3402 value is the same as for @code{TARGET_PCH_VALID_P}.",
3403 const char *, (int pch_flags), NULL)
3405 /* True if the compiler should give an enum type only as many
3406 bytes as it takes to represent the range of possible values of
3409 (default_short_enums,
3410 "This target hook should return true if the compiler should give an\n\
3411 @code{enum} type only as many bytes as it takes to represent the range\n\
3412 of possible values of that type. It should return false if all\n\
3413 @code{enum} types should be allocated like @code{int}.\n\
3415 The default is to return false.",
3417 hook_bool_void_false)
3419 /* This target hook returns an rtx that is used to store the address
3420 of the current frame into the built-in setjmp buffer. */
3422 (builtin_setjmp_frame_value,
3423 "This target hook should return an rtx that is used to store\n\
3424 the address of the current frame into the built in @code{setjmp} buffer.\n\
3425 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3426 machines. One reason you may need to define this target hook is if\n\
3427 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3429 default_builtin_setjmp_frame_value)
3431 /* This target hook should add STRING_CST trees for any hard regs
3432 the port wishes to automatically clobber for an asm. */
3435 "This target hook should add to @var{clobbers} @code{STRING_CST} trees for\n\
3436 any hard regs the port wishes to automatically clobber for an asm.\n\
3437 It should return the result of the last @code{tree_cons} used to add a\n\
3438 clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the\n\
3439 corresponding parameters to the asm and may be inspected to avoid\n\
3440 clobbering a register that is an input or output of the asm. You can use\n\
3441 @code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test\n\
3442 for overlap with regards to asm-declared registers.",
3443 tree, (tree outputs, tree inputs, tree clobbers),
3444 hook_tree_tree_tree_tree_3rd_identity)
3446 /* This target hook allows the backend to specify a calling convention
3447 in the debug information. This function actually returns an
3448 enum dwarf_calling_convention, but because of forward declarations
3449 and not wanting to include dwarf2.h everywhere target.h is included
3450 the function is being declared as an int. */
3452 (dwarf_calling_convention,
3453 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3454 be emitted for each function. Instead of an integer return the enum\n\
3455 value for the @code{DW_CC_} tag.",
3456 int, (const_tree function),
3457 hook_int_const_tree_0)
3459 /* This target hook allows the backend to emit frame-related insns that
3460 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3461 engine will invoke it on insns of the form
3462 (set (reg) (unspec [...] UNSPEC_INDEX))
3464 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3465 to let the backend emit the call frame instructions. */
3467 (dwarf_handle_frame_unspec,
3468 "This target hook allows the backend to emit frame-related insns that\n\
3469 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3470 info engine will invoke it on insns of the form\n\
3472 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3473 @end smallexample\n\
3476 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3477 @end smallexample\n\
3478 to let the backend emit the call frame instructions. @var{label} is\n\
3479 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3480 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3481 void, (const char *label, rtx pattern, int index), NULL)
3483 /* ??? Documenting this hook requires a GFDL license grant. */
3485 (stdarg_optimize_hook,
3486 "Perform architecture specific checking of statements gimplified\
3487 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
3488 the statement doesn't need to be checked for @code{va_list} references.",
3489 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)
3491 /* This target hook allows the operating system to override the DECL
3492 that represents the external variable that contains the stack
3493 protection guard variable. The type of this DECL is ptr_type_node. */
3495 (stack_protect_guard,
3496 "This hook returns a @code{DECL} node for the external variable to use\n\
3497 for the stack protection guard. This variable is initialized by the\n\
3498 runtime to some random value and is used to initialize the guard value\n\
3499 that is placed at the top of the local stack frame. The type of this\n\
3500 variable must be @code{ptr_type_node}.\n\
3502 The default version of this hook creates a variable called\n\
3503 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3505 default_stack_protect_guard)
3507 /* This target hook allows the operating system to override the CALL_EXPR
3508 that is invoked when a check vs the guard variable fails. */
3510 (stack_protect_fail,
3511 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3512 stack protect guard variable has been modified. This expression should\n\
3513 involve a call to a @code{noreturn} function.\n\
3515 The default version of this hook invokes a function called\n\
3516 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
3517 normally defined in @file{libgcc2.c}.",
3519 default_external_stack_protect_fail)
3523 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
3524 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
3525 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
3526 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
3527 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
3528 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
3529 loop is only entered from the top.\n\
3531 This hook is only used if @code{doloop_end} is available. The default\n\
3532 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
3533 if the loop must be the innermost, and if there are no other restrictions.",
3534 bool, (const widest_int &iterations, const widest_int &iterations_max,
3535 unsigned int loop_depth, bool entered_at_top),
3536 hook_bool_wint_wint_uint_bool_true)
3538 /* Returns NULL if target supports the insn within a doloop block,
3539 otherwise it returns an error message. */
3541 (invalid_within_doloop,
3543 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3544 low-overhead loop, otherwise return a string explaining why doloop\n\
3545 could not be applied.\n\
3547 Many targets use special registers for low-overhead looping. For any\n\
3548 instruction that clobbers these this function should return a string indicating\n\
3549 the reason why the doloop could not be applied.\n\
3550 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3551 loops containing function calls or branch on table instructions.",
3552 const char *, (const_rtx insn),
3553 default_invalid_within_doloop)
3555 /* Returns true for a legitimate combined insn. */
3557 (legitimate_combined_insn,
3558 "Take an instruction in @var{insn} and return @code{false} if the instruction\
3559 is not appropriate as a combination of two or more instructions. The\
3560 default is to accept all instructions.",
3565 (valid_dllimport_attribute_p,
3566 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3567 specified. Use this hook if the target needs to add extra validation\
3568 checks to @code{handle_dll_attribute}.",
3569 bool, (const_tree decl),
3570 hook_bool_const_tree_true)
3572 /* If non-zero, align constant anchors in CSE to a multiple of this
3576 "On some architectures it can take multiple instructions to synthesize\n\
3577 a constant. If there is another constant already in a register that\n\
3578 is close enough in value then it is preferable that the new constant\n\
3579 is computed from this register using immediate addition or\n\
3580 subtraction. We accomplish this through CSE. Besides the value of\n\
3581 the constant we also add a lower and an upper constant anchor to the\n\
3582 available expressions. These are then queried when encountering new\n\
3583 constants. The anchors are computed by rounding the constant up and\n\
3584 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3585 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3586 accepted by immediate-add plus one. We currently assume that the\n\
3587 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
3588 MIPS, where add-immediate takes a 16-bit signed value,\n\
3589 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
3590 is zero, which disables this optimization.",
3591 unsigned HOST_WIDE_INT, 0)
3593 /* Defines, which target-dependent bits (upper 16) are used by port */
3596 "Validate target specific memory model mask bits. When NULL no target specific\n\
3597 memory model bits are allowed.",
3598 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
3600 /* Defines an offset bitwise ored into shifted address to get corresponding
3601 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
3602 supported by the target. */
3604 (asan_shadow_offset,
3605 "Return the offset bitwise ored into shifted address to get corresponding\n\
3606 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
3607 supported by the target.",
3608 unsigned HOST_WIDE_INT, (void),
3611 /* Functions relating to calls - argument passing, returns, etc. */
3612 /* Members of struct call have no special macro prefix. */
3613 HOOK_VECTOR (TARGET_CALLS, calls)
3616 (promote_function_mode,
3617 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
3618 function return values. The target hook should return the new mode\n\
3619 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
3620 change signedness. This function is called only for scalar @emph{or\n\
3623 @var{for_return} allows to distinguish the promotion of arguments and\n\
3624 return values. If it is @code{1}, a return value is being promoted and\n\
3625 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
3626 If it is @code{2}, the returned mode should be that of the register in\n\
3627 which an incoming parameter is copied, or the outgoing result is computed;\n\
3628 then the hook should return the same mode as @code{promote_mode}, though\n\
3629 the signedness may be different.\n\
3631 @var{type} can be NULL when promoting function arguments of libcalls.\n\
3633 The default is to not promote arguments and return values. You can\n\
3634 also define the hook to @code{default_promote_function_mode_always_promote}\n\
3635 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
3636 enum machine_mode, (const_tree type, enum machine_mode mode, int *punsignedp,
3637 const_tree funtype, int for_return),
3638 default_promote_function_mode)
3641 (promote_prototypes,
3642 "This target hook returns @code{true} if an argument declared in a\n\
3643 prototype as an integral type smaller than @code{int} should actually be\n\
3644 passed as an @code{int}. In addition to avoiding errors in certain\n\
3645 cases of mismatch, it also makes for better code on certain machines.\n\
3646 The default is to not promote prototypes.",
3647 bool, (const_tree fntype),
3648 hook_bool_const_tree_false)
3652 "This target hook should return the location of the structure value\n\
3653 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
3654 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
3655 be @code{NULL}, for libcalls. You do not need to define this target\n\
3656 hook if the address is always passed as an ``invisible'' first\n\
3659 On some architectures the place where the structure value address\n\
3660 is found by the called function is not the same place that the\n\
3661 caller put it. This can be due to register windows, or it could\n\
3662 be because the function prologue moves it to a different place.\n\
3663 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
3664 the context of the called function, and @code{0} in the context of\n\
3667 If @var{incoming} is nonzero and the address is to be found on the\n\
3668 stack, return a @code{mem} which refers to the frame pointer. If\n\
3669 @var{incoming} is @code{2}, the result is being used to fetch the\n\
3670 structure value address at the beginning of a function. If you need\n\
3671 to emit adjusting code, you should do it at this point.",
3672 rtx, (tree fndecl, int incoming),
3673 hook_rtx_tree_int_null)
3676 "This target hook should return a nonzero value to say to return the\n\
3677 function value in memory, just as large structures are always returned.\n\
3678 Here @var{type} will be the data type of the value, and @var{fntype}\n\
3679 will be the type of the function doing the returning, or @code{NULL} for\n\
3682 Note that values of mode @code{BLKmode} must be explicitly handled\n\
3683 by this function. Also, the option @option{-fpcc-struct-return}\n\
3684 takes effect regardless of this macro. On most systems, it is\n\
3685 possible to leave the hook undefined; this causes a default\n\
3686 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
3687 values, and 0 otherwise.\n\
3689 Do not use this hook to indicate that structures and unions should always\n\
3690 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
3692 bool, (const_tree type, const_tree fntype),
3693 default_return_in_memory)
3697 "This hook should return true if values of type @var{type} are returned\n\
3698 at the most significant end of a register (in other words, if they are\n\
3699 padded at the least significant end). You can assume that @var{type}\n\
3700 is returned in a register; the caller is required to check this.\n\
3702 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
3703 be able to hold the complete return value. For example, if a 1-, 2-\n\
3704 or 3-byte structure is returned at the most significant end of a\n\
3705 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
3706 @code{SImode} rtx.",
3707 bool, (const_tree type),
3708 hook_bool_const_tree_false)
3710 /* Return true if a parameter must be passed by reference. TYPE may
3711 be null if this is a libcall. CA may be null if this query is
3712 from __builtin_va_arg. */
3715 "This target hook should return @code{true} if an argument at the\n\
3716 position indicated by @var{cum} should be passed by reference. This\n\
3717 predicate is queried after target independent reasons for being\n\
3718 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
3720 If the hook returns true, a copy of that argument is made in memory and a\n\
3721 pointer to the argument is passed instead of the argument itself.\n\
3722 The pointer is passed in whatever way is appropriate for passing a pointer\n\
3725 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3726 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3729 (expand_builtin_saveregs,
3730 "If defined, this hook produces the machine-specific code for a call to\n\
3731 @code{__builtin_saveregs}. This code will be moved to the very\n\
3732 beginning of the function, before any parameter access are made. The\n\
3733 return value of this function should be an RTX that contains the value\n\
3734 to use as the return of @code{__builtin_saveregs}.",
3736 default_expand_builtin_saveregs)
3738 /* Returns pretend_argument_size. */
3740 (setup_incoming_varargs,
3741 "This target hook offers an alternative to using\n\
3742 @code{__builtin_saveregs} and defining the hook\n\
3743 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
3744 register arguments into the stack so that all the arguments appear to\n\
3745 have been passed consecutively on the stack. Once this is done, you can\n\
3746 use the standard implementation of varargs that works for machines that\n\
3747 pass all their arguments on the stack.\n\
3749 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
3750 structure, containing the values that are obtained after processing the\n\
3751 named arguments. The arguments @var{mode} and @var{type} describe the\n\
3752 last named argument---its machine mode and its data type as a tree node.\n\
3754 The target hook should do two things: first, push onto the stack all the\n\
3755 argument registers @emph{not} used for the named arguments, and second,\n\
3756 store the size of the data thus pushed into the @code{int}-valued\n\
3757 variable pointed to by @var{pretend_args_size}. The value that you\n\
3758 store here will serve as additional offset for setting up the stack\n\
3761 Because you must generate code to push the anonymous arguments at\n\
3762 compile time without knowing their data types,\n\
3763 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
3764 have just a single category of argument register and use it uniformly\n\
3765 for all data types.\n\
3767 If the argument @var{second_time} is nonzero, it means that the\n\
3768 arguments of the function are being analyzed for the second time. This\n\
3769 happens for an inline function, which is not actually compiled until the\n\
3770 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
3771 not generate any instructions in this case.",
3772 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
3773 int *pretend_args_size, int second_time),
3774 default_setup_incoming_varargs)
3777 (strict_argument_naming,
3778 "Define this hook to return @code{true} if the location where a function\n\
3779 argument is passed depends on whether or not it is a named argument.\n\
3781 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
3782 is set for varargs and stdarg functions. If this hook returns\n\
3783 @code{true}, the @var{named} argument is always true for named\n\
3784 arguments, and false for unnamed arguments. If it returns @code{false},\n\
3785 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
3786 then all arguments are treated as named. Otherwise, all named arguments\n\
3787 except the last are treated as named.\n\
3789 You need not define this hook if it always returns @code{false}.",
3790 bool, (cumulative_args_t ca),
3791 hook_bool_CUMULATIVE_ARGS_false)
3793 /* Returns true if we should use
3794 targetm.calls.setup_incoming_varargs() and/or
3795 targetm.calls.strict_argument_naming(). */
3797 (pretend_outgoing_varargs_named,
3798 "If you need to conditionally change ABIs so that one works with\n\
3799 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
3800 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
3801 defined, then define this hook to return @code{true} if\n\
3802 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
3803 Otherwise, you should not define this hook.",
3804 bool, (cumulative_args_t ca),
3805 default_pretend_outgoing_varargs_named)
3807 /* Given a complex type T, return true if a parameter of type T
3808 should be passed as two scalars. */
3811 "This hook should return true if parameter of type @var{type} are passed\n\
3812 as two scalar parameters. By default, GCC will attempt to pack complex\n\
3813 arguments into the target's word size. Some ABIs require complex arguments\n\
3814 to be split and treated as their individual components. For example, on\n\
3815 AIX64, complex floats should be passed in a pair of floating point\n\
3816 registers, even though a complex float would fit in one 64-bit floating\n\
3819 The default value of this hook is @code{NULL}, which is treated as always\n\
3821 bool, (const_tree type), NULL)
3823 /* Return true if type T, mode MODE, may not be passed in registers,
3824 but must be passed on the stack. */
3825 /* ??? This predicate should be applied strictly after pass-by-reference.
3826 Need audit to verify that this is the case. */
3828 (must_pass_in_stack,
3829 "This target hook should return @code{true} if we should not pass @var{type}\n\
3830 solely in registers. The file @file{expr.h} defines a\n\
3831 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
3833 bool, (enum machine_mode mode, const_tree type),
3834 must_pass_in_stack_var_size_or_pad)
3836 /* Return true if type TYPE, mode MODE, which is passed by reference,
3837 should have the object copy generated by the callee rather than
3838 the caller. It is never called for TYPE requiring constructors. */
3841 "The function argument described by the parameters to this hook is\n\
3842 known to be passed by reference. The hook should return true if the\n\
3843 function argument should be copied by the callee instead of copied\n\
3846 For any argument for which the hook returns true, if it can be\n\
3847 determined that the argument is not modified, then a copy need\n\
3848 not be generated.\n\
3850 The default version of this hook always returns false.",
3852 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3853 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3855 /* Return zero for arguments passed entirely on the stack or entirely
3856 in registers. If passed in both, return the number of bytes passed
3857 in registers; the balance is therefore passed on the stack. */
3860 "This target hook returns the number of bytes at the beginning of an\n\
3861 argument that must be put in registers. The value must be zero for\n\
3862 arguments that are passed entirely in registers or that are entirely\n\
3863 pushed on the stack.\n\
3865 On some machines, certain arguments must be passed partially in\n\
3866 registers and partially in memory. On these machines, typically the\n\
3867 first few words of arguments are passed in registers, and the rest\n\
3868 on the stack. If a multi-word argument (a @code{double} or a\n\
3869 structure) crosses that boundary, its first few words must be passed\n\
3870 in registers and the rest must be pushed. This macro tells the\n\
3871 compiler when this occurs, and how many bytes should go in registers.\n\
3873 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
3874 register to be used by the caller for this argument; likewise\n\
3875 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
3876 int, (cumulative_args_t cum, enum machine_mode mode, tree type, bool named),
3877 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
3879 /* Update the state in CA to advance past an argument in the
3880 argument list. The values MODE, TYPE, and NAMED describe that
3883 (function_arg_advance,
3884 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
3885 advance past an argument in the argument list. The values @var{mode},\n\
3886 @var{type} and @var{named} describe that argument. Once this is done,\n\
3887 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
3888 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
3890 This hook need not do anything if the argument in question was passed\n\
3891 on the stack. The compiler knows how to track the amount of stack space\n\
3892 used for arguments without any special help.",
3894 (cumulative_args_t ca, enum machine_mode mode, const_tree type, bool named),
3895 default_function_arg_advance)
3897 /* Return zero if the argument described by the state of CA should
3898 be placed on a stack, or a hard register in which to store the
3899 argument. The values MODE, TYPE, and NAMED describe that
3903 "Return an RTX indicating whether a function argument is passed in a\n\
3904 register and if so, which register.\n\
3906 The arguments are @var{ca}, which summarizes all the previous\n\
3907 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
3908 the data type of the argument as a tree node or 0 if that is not known\n\
3909 (which happens for C support library functions); and @var{named},\n\
3910 which is @code{true} for an ordinary argument and @code{false} for\n\
3911 nameless arguments that correspond to @samp{@dots{}} in the called\n\
3912 function's prototype. @var{type} can be an incomplete type if a\n\
3913 syntax error has previously occurred.\n\
3915 The return value is usually either a @code{reg} RTX for the hard\n\
3916 register in which to pass the argument, or zero to pass the argument\n\
3919 The value of the expression can also be a @code{parallel} RTX@. This is\n\
3920 used when an argument is passed in multiple locations. The mode of the\n\
3921 @code{parallel} should be the mode of the entire argument. The\n\
3922 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
3923 describes where part of the argument is passed. In each\n\
3924 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
3925 register in which to pass this part of the argument, and the mode of the\n\
3926 register RTX indicates how large this part of the argument is. The\n\
3927 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
3928 the offset in bytes into the entire argument of where this part starts.\n\
3929 As a special exception the first @code{expr_list} in the @code{parallel}\n\
3930 RTX may have a first operand of zero. This indicates that the entire\n\
3931 argument is also stored on the stack.\n\
3933 The last time this hook is called, it is called with @code{MODE ==\n\
3934 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
3935 pattern as operands 2 and 3 respectively.\n\
3937 @cindex @file{stdarg.h} and register arguments\n\
3938 The usual way to make the ISO library @file{stdarg.h} work on a\n\
3939 machine where some arguments are usually passed in registers, is to\n\
3940 cause nameless arguments to be passed on the stack instead. This is\n\
3941 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
3942 @var{named} is @code{false}.\n\
3944 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
3945 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
3946 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
3947 in the definition of this macro to determine if this argument is of a\n\
3948 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
3949 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
3950 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
3951 defined, the argument will be computed in the stack and then loaded into\n\
3953 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3955 default_function_arg)
3957 /* Likewise, but for machines with register windows. Return the
3958 location where the argument will appear to the callee. */
3960 (function_incoming_arg,
3961 "Define this hook if the target machine has ``register windows'', so\n\
3962 that the register in which a function sees an arguments is not\n\
3963 necessarily the same as the one in which the caller passed the\n\
3966 For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
3967 which the caller passes the value, and\n\
3968 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
3969 fashion to tell the function being called where the arguments will\n\
3972 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
3973 @code{TARGET_FUNCTION_ARG} serves both purposes.",
3974 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3976 default_function_incoming_arg)
3979 (function_arg_boundary,
3980 "This hook returns the alignment boundary, in bits, of an argument\n\
3981 with the specified mode and type. The default hook returns\n\
3982 @code{PARM_BOUNDARY} for all arguments.",
3983 unsigned int, (enum machine_mode mode, const_tree type),
3984 default_function_arg_boundary)
3987 (function_arg_round_boundary,
3988 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
3989 which is the default value for this hook. You can define this hook to\n\
3990 return a different value if an argument size must be rounded to a larger\n\
3992 unsigned int, (enum machine_mode mode, const_tree type),
3993 default_function_arg_round_boundary)
3995 /* Return the diagnostic message string if function without a prototype
3996 is not allowed for this 'val' argument; NULL otherwise. */
3998 (invalid_arg_for_unprototyped_fn,
3999 "If defined, this macro returns the diagnostic message when it is\n\
4000 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4001 with prototype @var{typelist}.",
4002 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4003 hook_invalid_arg_for_unprototyped_fn)
4005 /* Return an rtx for the return value location of the function
4006 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4010 Define this to return an RTX representing the place where a function\n\
4011 returns or receives a value of data type @var{ret_type}, a tree node\n\
4012 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4013 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4014 function being called. If @var{outgoing} is false, the hook should\n\
4015 compute the register in which the caller will see the return value.\n\
4016 Otherwise, the hook should return an RTX representing the place where\n\
4017 a function returns a value.\n\
4019 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4020 (Actually, on most machines, scalar values are returned in the same\n\
4021 place regardless of mode.) The value of the expression is usually a\n\
4022 @code{reg} RTX for the hard register where the return value is stored.\n\
4023 The value can also be a @code{parallel} RTX, if the return value is in\n\
4024 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4025 @code{parallel} form. Note that the callee will populate every\n\
4026 location specified in the @code{parallel}, but if the first element of\n\
4027 the @code{parallel} contains the whole return value, callers will use\n\
4028 that element as the canonical location and ignore the others. The m68k\n\
4029 port uses this type of @code{parallel} to return pointers in both\n\
4030 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4032 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4033 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4034 @var{valtype} is a scalar type.\n\
4036 If the precise function being called is known, @var{func} is a tree\n\
4037 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4038 pointer. This makes it possible to use a different value-returning\n\
4039 convention for specific functions when all their calls are\n\
4042 Some target machines have ``register windows'' so that the register in\n\
4043 which a function returns its value is not the same as the one in which\n\
4044 the caller sees the value. For such machines, you should return\n\
4045 different RTX depending on @var{outgoing}.\n\
4047 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4048 aggregate data types, because these are returned in another way. See\n\
4049 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4050 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4051 default_function_value)
4053 /* Return the rtx for the result of a libcall of mode MODE,
4054 calling the function FN_NAME. */
4057 "Define this hook if the back-end needs to know the name of the libcall\n\
4058 function in order to determine where the result should be returned.\n\
4060 The mode of the result is given by @var{mode} and the name of the called\n\
4061 library function is given by @var{fun}. The hook should return an RTX\n\
4062 representing the place where the library function result will be returned.\n\
4064 If this hook is not defined, then LIBCALL_VALUE will be used.",
4065 rtx, (enum machine_mode mode, const_rtx fun),
4066 default_libcall_value)
4068 /* Return true if REGNO is a possible register number for
4069 a function value as seen by the caller. */
4071 (function_value_regno_p,
4072 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4073 register in which the values of called function may come back.\n\
4075 A register whose use for returning values is limited to serving as the\n\
4076 second of a pair (for a value of type @code{double}, say) need not be\n\
4077 recognized by this target hook.\n\
4079 If the machine has register windows, so that the caller and the called\n\
4080 function use different registers for the return value, this target hook\n\
4081 should recognize only the caller's register numbers.\n\
4083 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4084 bool, (const unsigned int regno),
4085 default_function_value_regno_p)
4087 /* ??? Documenting this hook requires a GFDL license grant. */
4089 (internal_arg_pointer,
4090 "Return an rtx for the argument pointer incoming to the\
4093 default_internal_arg_pointer)
4095 /* Update the current function stack boundary if needed. */
4097 (update_stack_boundary,
4098 "Define this macro to update the current function stack boundary if\n\
4102 /* Handle stack alignment and return an rtx for Dynamic Realign
4103 Argument Pointer if necessary. */
4106 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4107 different argument pointer register is needed to access the function's\n\
4108 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4112 /* Return true if all function parameters should be spilled to the
4115 (allocate_stack_slots_for_args,
4116 "When optimization is disabled, this hook indicates whether or not\n\
4117 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4118 stacks slots for arguments when not optimizing in order to make\n\
4119 debugging easier. However, when a function is declared with\n\
4120 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4121 cannot safely move arguments from the registers in which they are passed\n\
4122 to the stack. Therefore, this hook should return true in general, but\n\
4123 false for naked functions. The default implementation always returns true.",
4125 hook_bool_void_true)
4127 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
4128 then it should be for the callee; otherwise for the caller. */
4131 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4132 targets that may use different static chain locations for different\n\
4133 nested functions. This may be required if the target has function\n\
4134 attributes that affect the calling conventions of the function and\n\
4135 those calling conventions use different static chain locations.\n\
4137 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4139 If the static chain is passed in memory, this hook should be used to\n\
4140 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4141 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4142 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4143 will be at an offset from the frame pointer.\n\
4144 @findex stack_pointer_rtx\n\
4145 @findex frame_pointer_rtx\n\
4146 @findex arg_pointer_rtx\n\
4147 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4148 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4149 to refer to those items.",
4150 rtx, (const_tree fndecl, bool incoming_p),
4151 default_static_chain)
4153 /* Fill in the trampoline at MEM with a call to FNDECL and a
4154 static chain value of CHAIN. */
4157 "This hook is called to initialize a trampoline.\n\
4158 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4159 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4160 RTX for the static chain value that should be passed to the function\n\
4161 when it is called.\n\
4163 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4164 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4165 from the memory block returned by @code{assemble_trampoline_template}.\n\
4166 Note that the block move need only cover the constant parts of the\n\
4167 trampoline. If the target isolates the variable parts of the trampoline\n\
4168 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4170 If the target requires any other actions, such as flushing caches or\n\
4171 enabling stack execution, these actions should be performed after\n\
4172 initializing the trampoline proper.",
4173 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4174 default_trampoline_init)
4176 /* Adjust the address of the trampoline in a target-specific way. */
4178 (trampoline_adjust_address,
4179 "This hook should perform any machine-specific adjustment in\n\
4180 the address of the trampoline. Its argument contains the address of the\n\
4181 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4182 the address to be used for a function call should be different from the\n\
4183 address at which the template was stored, the different address should\n\
4184 be returned; otherwise @var{addr} should be returned unchanged.\n\
4185 If this hook is not defined, @var{addr} will be used for function calls.",
4186 rtx, (rtx addr), NULL)
4188 /* Return the number of bytes of its own arguments that a function
4189 pops on returning, or 0 if the function pops no arguments and the
4190 caller must therefore pop them all after the function returns. */
4191 /* ??? tm.texi has no types for the parameters. */
4194 "This target hook returns the number of bytes of its own arguments that\n\
4195 a function pops on returning, or 0 if the function pops no arguments\n\
4196 and the caller must therefore pop them all after the function returns.\n\
4198 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4199 the function in question. Normally it is a node of type\n\
4200 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4201 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4203 @var{funtype} is a C variable whose value is a tree node that\n\
4204 describes the function in question. Normally it is a node of type\n\
4205 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4206 From this it is possible to obtain the data types of the value and\n\
4207 arguments (if known).\n\
4209 When a call to a library function is being considered, @var{fundecl}\n\
4210 will contain an identifier node for the library function. Thus, if\n\
4211 you need to distinguish among various library functions, you can do so\n\
4212 by their names. Note that ``library function'' in this context means\n\
4213 a function used to perform arithmetic, whose name is known specially\n\
4214 in the compiler and was not mentioned in the C code being compiled.\n\
4216 @var{size} is the number of bytes of arguments passed on the\n\
4217 stack. If a variable number of bytes is passed, it is zero, and\n\
4218 argument popping will always be the responsibility of the calling function.\n\
4220 On the VAX, all functions always pop their arguments, so the definition\n\
4221 of this macro is @var{size}. On the 68000, using the standard\n\
4222 calling convention, no functions pop their arguments, so the value of\n\
4223 the macro is always 0 in this case. But an alternative calling\n\
4224 convention is available in which functions that take a fixed number of\n\
4225 arguments pop them but other functions (such as @code{printf}) pop\n\
4226 nothing (the caller pops all). When this convention is in use,\n\
4227 @var{funtype} is examined to determine whether a function takes a fixed\n\
4228 number of arguments.",
4229 int, (tree fundecl, tree funtype, int size),
4230 default_return_pops_args)
4232 /* Return a mode wide enough to copy any function value that might be
4235 (get_raw_result_mode,
4236 "This target hook returns the mode to be used when accessing raw return\
4237 registers in @code{__builtin_return}. Define this macro if the value\
4238 in @var{reg_raw_mode} is not correct.",
4239 enum machine_mode, (int regno),
4240 default_get_reg_raw_mode)
4242 /* Return a mode wide enough to copy any argument value that might be
4246 "This target hook returns the mode to be used when accessing raw argument\
4247 registers in @code{__builtin_apply_args}. Define this macro if the value\
4248 in @var{reg_raw_mode} is not correct.",
4249 enum machine_mode, (int regno),
4250 default_get_reg_raw_mode)
4252 HOOK_VECTOR_END (calls)
4254 /* Return the diagnostic message string if conversion from FROMTYPE
4255 to TOTYPE is not allowed, NULL otherwise. */
4257 (invalid_conversion,
4258 "If defined, this macro returns the diagnostic message when it is\n\
4259 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4260 if validity should be determined by the front end.",
4261 const char *, (const_tree fromtype, const_tree totype),
4262 hook_constcharptr_const_tree_const_tree_null)
4264 /* Return the diagnostic message string if the unary operation OP is
4265 not permitted on TYPE, NULL otherwise. */
4268 "If defined, this macro returns the diagnostic message when it is\n\
4269 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4270 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4271 if validity should be determined by the front end.",
4272 const char *, (int op, const_tree type),
4273 hook_constcharptr_int_const_tree_null)
4275 /* Return the diagnostic message string if the binary operation OP
4276 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4279 "If defined, this macro returns the diagnostic message when it is\n\
4280 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4281 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4283 const char *, (int op, const_tree type1, const_tree type2),
4284 hook_constcharptr_int_const_tree_const_tree_null)
4286 /* Return the diagnostic message string if TYPE is not valid as a
4287 function parameter type, NULL otherwise. */
4289 (invalid_parameter_type,
4290 "If defined, this macro returns the diagnostic message when it is\n\
4291 invalid for functions to include parameters of type @var{type},\n\
4292 or @code{NULL} if validity should be determined by\n\
4293 the front end. This is currently used only by the C and C++ front ends.",
4294 const char *, (const_tree type),
4295 hook_constcharptr_const_tree_null)
4297 /* Return the diagnostic message string if TYPE is not valid as a
4298 function return type, NULL otherwise. */
4300 (invalid_return_type,
4301 "If defined, this macro returns the diagnostic message when it is\n\
4302 invalid for functions to have return type @var{type},\n\
4303 or @code{NULL} if validity should be determined by\n\
4304 the front end. This is currently used only by the C and C++ front ends.",
4305 const char *, (const_tree type),
4306 hook_constcharptr_const_tree_null)
4308 /* If values of TYPE are promoted to some other type when used in
4309 expressions (analogous to the integer promotions), return that type,
4310 or NULL_TREE otherwise. */
4313 "If defined, this target hook returns the type to which values of\n\
4314 @var{type} should be promoted when they appear in expressions,\n\
4315 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4316 front end's normal promotion rules. This hook is useful when there are\n\
4317 target-specific types with special promotion rules.\n\
4318 This is currently used only by the C and C++ front ends.",
4319 tree, (const_tree type),
4320 hook_tree_const_tree_null)
4322 /* Convert EXPR to TYPE, if target-specific types with special conversion
4323 rules are involved. Return the converted expression, or NULL to apply
4324 the standard conversion rules. */
4327 "If defined, this hook returns the result of converting @var{expr} to\n\
4328 @var{type}. It should return the converted expression,\n\
4329 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4330 This hook is useful when there are target-specific types with special\n\
4331 conversion rules.\n\
4332 This is currently used only by the C and C++ front ends.",
4333 tree, (tree type, tree expr),
4334 hook_tree_tree_tree_null)
4336 /* Return true if we use LRA instead of reload. */
4339 "A target hook which returns true if we use LRA instead of reload pass.\
4340 It means that LRA was ported to the target.\
4342 The default version of this target hook returns always false.",
4346 /* Return register priority of given hard regno for the current target. */
4349 "A target hook which returns the register priority number to which the\
4350 register @var{hard_regno} belongs to. The bigger the number, the\
4351 more preferable the hard register usage (when all other conditions are\
4352 the same). This hook can be used to prefer some hard register over\
4353 others in LRA. For example, some x86-64 register usage needs\
4354 additional prefix which makes instructions longer. The hook can\
4355 return lower priority number for such registers make them less favorable\
4356 and as result making the generated code smaller.\
4358 The default version of this target hook returns always zero.",
4360 default_register_priority)
4362 /* Return true if we need register usage leveling. */
4364 (register_usage_leveling_p,
4365 "A target hook which returns true if we need register usage leveling.\
4366 That means if a few hard registers are equally good for the\
4367 assignment, we choose the least used hard register. The register\
4368 usage leveling may be profitable for some targets. Don't use the\
4369 usage leveling for targets with conditional execution or targets\
4370 with big register files as it hurts if-conversion and cross-jumping\
4373 The default version of this target hook returns always false.",
4375 default_register_usage_leveling_p)
4377 /* Return true if maximal address displacement can be different. */
4379 (different_addr_displacement_p,
4380 "A target hook which returns true if an address with the same structure\
4381 can have different maximal legitimate displacement. For example, the\
4382 displacement can depend on memory mode or on operand combinations in\
4385 The default version of this target hook returns always false.",
4387 default_different_addr_displacement_p)
4389 /* Determine class for spilling pseudos of given mode into registers
4390 instead of memory. */
4393 "This hook defines a class of registers which could be used for spilling\
4394 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4395 should be used. Not defining this hook is equivalent to returning\
4396 @code{NO_REGS} for all inputs.",
4397 reg_class_t, (reg_class_t, enum machine_mode),
4402 "This hook defines the machine mode to use for the boolean result of\
4403 conditional store patterns. The ICODE argument is the instruction code\
4404 for the cstore being performed. Not definiting this hook is the same\
4405 as accepting the mode encoded into operand 0 of the cstore expander\
4407 enum machine_mode, (enum insn_code icode),
4408 default_cstore_mode)
4410 /* True if a structure, union or array with MODE containing FIELD should
4411 be accessed using BLKmode. */
4413 (member_type_forces_blk,
4414 "Return true if a structure, union or array containing @var{field} should\n\
4415 be accessed using @code{BLKMODE}.\n\
4417 If @var{field} is the only field in the structure, @var{mode} is its\n\
4418 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
4419 case where structures of one field would require the structure's mode to\n\
4420 retain the field's mode.\n\
4422 Normally, this is not needed.",
4423 bool, (const_tree field, enum machine_mode mode),
4424 default_member_type_forces_blk)
4426 /* Return the class for a secondary reload, and fill in extra information. */
4429 "Many machines have some registers that cannot be copied directly to or\n\
4430 from memory or even from other types of registers. An example is the\n\
4431 @samp{MQ} register, which on most machines, can only be copied to or\n\
4432 from general registers, but not memory. Below, we shall be using the\n\
4433 term 'intermediate register' when a move operation cannot be performed\n\
4434 directly, but has to be done by copying the source into the intermediate\n\
4435 register first, and then copying the intermediate register to the\n\
4436 destination. An intermediate register always has the same mode as\n\
4437 source and destination. Since it holds the actual value being copied,\n\
4438 reload might apply optimizations to re-use an intermediate register\n\
4439 and eliding the copy from the source when it can determine that the\n\
4440 intermediate register still holds the required value.\n\
4442 Another kind of secondary reload is required on some machines which\n\
4443 allow copying all registers to and from memory, but require a scratch\n\
4444 register for stores to some memory locations (e.g., those with symbolic\n\
4445 address on the RT, and those with certain symbolic address on the SPARC\n\
4446 when compiling PIC)@. Scratch registers need not have the same mode\n\
4447 as the value being copied, and usually hold a different value than\n\
4448 that being copied. Special patterns in the md file are needed to\n\
4449 describe how the copy is performed with the help of the scratch register;\n\
4450 these patterns also describe the number, register class(es) and mode(s)\n\
4451 of the scratch register(s).\n\
4453 In some cases, both an intermediate and a scratch register are required.\n\
4455 For input reloads, this target hook is called with nonzero @var{in_p},\n\
4456 and @var{x} is an rtx that needs to be copied to a register of class\n\
4457 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
4458 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4459 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4461 If copying a register of @var{reload_class} from/to @var{x} requires\n\
4462 an intermediate register, the hook @code{secondary_reload} should\n\
4463 return the register class required for this intermediate register.\n\
4464 If no intermediate register is required, it should return NO_REGS.\n\
4465 If more than one intermediate register is required, describe the one\n\
4466 that is closest in the copy chain to the reload register.\n\
4468 If scratch registers are needed, you also have to describe how to\n\
4469 perform the copy from/to the reload register to/from this\n\
4470 closest intermediate register. Or if no intermediate register is\n\
4471 required, but still a scratch register is needed, describe the\n\
4472 copy from/to the reload register to/from the reload operand @var{x}.\n\
4474 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4475 in the md file which performs the move. Operands 0 and 1 are the output\n\
4476 and input of this copy, respectively. Operands from operand 2 onward are\n\
4477 for scratch operands. These scratch operands must have a mode, and a\n\
4478 single-register-class\n\
4479 @c [later: or memory]\n\
4480 output constraint.\n\
4482 When an intermediate register is used, the @code{secondary_reload}\n\
4483 hook will be called again to determine how to copy the intermediate\n\
4484 register to/from the reload operand @var{x}, so your hook must also\n\
4485 have code to handle the register class of the intermediate operand.\n\
4487 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
4488 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
4489 @c and match the constraints of input and output to determine the required\n\
4490 @c alternative. A restriction would be that constraints used to match\n\
4491 @c against reloads registers would have to be written as register class\n\
4492 @c constraints, or we need a new target macro / hook that tells us if an\n\
4493 @c arbitrary constraint can match an unknown register of a given class.\n\
4494 @c Such a macro / hook would also be useful in other places.]\n\
4497 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
4498 pseudo-register, which could either be in a hard register or in memory.\n\
4499 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
4500 in memory and the hard register number if it is in a register.\n\
4502 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
4503 currently not supported. For the time being, you will have to continue\n\
4504 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
4506 @code{copy_cost} also uses this target hook to find out how values are\n\
4507 copied. If you want it to include some extra cost for the need to allocate\n\
4508 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
4509 Or if two dependent moves are supposed to have a lower cost than the sum\n\
4510 of the individual moves due to expected fortuitous scheduling and/or special\n\
4511 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
4513 (bool in_p, rtx x, reg_class_t reload_class, enum machine_mode reload_mode,
4514 secondary_reload_info *sri),
4515 default_secondary_reload)
4517 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
4518 return the class of reg to actually use. */
4520 (preferred_reload_class,
4521 "A target hook that places additional restrictions on the register class\n\
4522 to use when it is necessary to copy value @var{x} into a register in class\n\
4523 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
4524 another, smaller class.\n\
4526 The default version of this hook always returns value of @code{rclass} argument.\n\
4528 Sometimes returning a more restrictive class makes better code. For\n\
4529 example, on the 68000, when @var{x} is an integer constant that is in range\n\
4530 for a @samp{moveq} instruction, the value of this macro is always\n\
4531 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
4532 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
4534 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
4535 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
4536 loaded into some register class. By returning @code{NO_REGS} you can\n\
4537 force @var{x} into a memory location. For example, rs6000 can load\n\
4538 immediate values into general-purpose registers, but does not have an\n\
4539 instruction for loading an immediate value into a floating-point\n\
4540 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
4541 @var{x} is a floating-point constant. If the constant can't be loaded\n\
4542 into any kind of register, code generation will be better if\n\
4543 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
4544 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
4546 If an insn has pseudos in it after register allocation, reload will go\n\
4547 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
4548 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
4549 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
4550 this feature to discourage usage of 387 registers when math is done in\n\
4551 the SSE registers (and vice versa).",
4553 (rtx x, reg_class_t rclass),
4554 default_preferred_reload_class)
4556 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
4559 (preferred_output_reload_class,
4560 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
4563 The default version of this hook always returns value of @code{rclass}\n\
4566 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
4567 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
4569 (rtx x, reg_class_t rclass),
4570 default_preferred_output_reload_class)
4573 (class_likely_spilled_p,
4574 "A target hook which returns @code{true} if pseudos that have been assigned\n\
4575 to registers of class @var{rclass} would likely be spilled because\n\
4576 registers of @var{rclass} are needed for spill registers.\n\
4578 The default version of this target hook returns @code{true} if @var{rclass}\n\
4579 has exactly one register and @code{false} otherwise. On most machines, this\n\
4580 default should be used. For generally register-starved machines, such as\n\
4581 i386, or machines with right register constraints, such as SH, this hook\n\
4582 can be used to avoid excessive spilling.\n\
4584 This hook is also used by some of the global intra-procedural code\n\
4585 transformations to throtle code motion, to avoid increasing register\n\
4587 bool, (reg_class_t rclass),
4588 default_class_likely_spilled_p)
4590 /* Return the maximum number of consecutive registers
4591 needed to represent mode MODE in a register of class RCLASS. */
4594 "A target hook returns the maximum number of consecutive registers\n\
4595 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
4597 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
4598 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
4599 @var{mode})} target hook should be the maximum value of\n\
4600 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
4601 values in the class @var{rclass}.\n\
4603 This target hook helps control the handling of multiple-word values\n\
4604 in the reload pass.\n\
4606 The default version of this target hook returns the size of @var{mode}\n\
4608 unsigned char, (reg_class_t rclass, enum machine_mode mode),
4609 default_class_max_nregs)
4612 (preferred_rename_class,
4613 "A target hook that places additional preference on the register\
4614 class to use when it is necessary to rename a register in class\
4615 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
4616 preferred register class is found or hook @code{preferred_rename_class}\
4617 is not implemented.\
4618 Sometimes returning a more restrictive class makes better code. For\
4619 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
4620 smaller than instructions using @code{GENERIC_REGS}. By returning\
4621 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
4623 reg_class_t, (reg_class_t rclass),
4624 default_preferred_rename_class)
4626 /* This target hook allows the backend to perform additional
4627 processing while initializing for variable expansion. */
4629 (expand_to_rtl_hook,
4630 "This hook is called just before expansion into rtl, allowing the target\n\
4631 to perform additional initializations or analysis before the expansion.\n\
4632 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
4633 for use in copying SDmode values between memory and floating point\n\
4634 registers whenever the function being expanded has any SDmode\n\
4639 /* This target hook allows the backend to perform additional
4640 instantiations on rtx that are not actually in insns yet,
4641 but will be later. */
4644 "This hook allows the backend to perform additional instantiations on rtl\n\
4645 that are not actually in any insns yet, but will be later.",
4649 /* Return true if is OK to use a hard register REGNO as scratch register
4652 (hard_regno_scratch_ok,
4653 "This target hook should return @code{true} if it is OK to use a hard register\n\
4654 @var{regno} as scratch reg in peephole2.\n\
4656 One common use of this macro is to prevent using of a register that\n\
4657 is not saved by a prologue in an interrupt handler.\n\
4659 The default version of this hook always returns @code{true}.",
4660 bool, (unsigned int regno),
4661 default_hard_regno_scratch_ok)
4663 /* Return the smallest number of different values for which it is best to
4664 use a jump-table instead of a tree of conditional branches. */
4666 (case_values_threshold,
4667 "This function return the smallest number of different values for which it\n\
4668 is best to use a jump-table instead of a tree of conditional branches.\n\
4669 The default is four for machines with a @code{casesi} instruction and\n\
4670 five otherwise. This is best for most machines.",
4671 unsigned int, (void),
4672 default_case_values_threshold)
4674 /* Retutn true if a function must have and use a frame pointer. */
4676 (frame_pointer_required,
4677 "This target hook should return @code{true} if a function must have and use\n\
4678 a frame pointer. This target hook is called in the reload pass. If its return\n\
4679 value is @code{true} the function will have a frame pointer.\n\
4681 This target hook can in principle examine the current function and decide\n\
4682 according to the facts, but on most machines the constant @code{false} or the\n\
4683 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
4684 to be generated with no frame pointer, and doing so saves some time or space.\n\
4685 Use @code{true} when there is no possible advantage to avoiding a frame\n\
4688 In certain cases, the compiler does not know how to produce valid code\n\
4689 without a frame pointer. The compiler recognizes those cases and\n\
4690 automatically gives the function a frame pointer regardless of what\n\
4691 @code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about\n\
4694 In a function that does not require a frame pointer, the frame pointer\n\
4695 register can be allocated for ordinary usage, unless you mark it as a\n\
4696 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
4698 Default return value is @code{false}.",
4700 hook_bool_void_false)
4702 /* Returns true if the compiler is allowed to try to replace register number
4703 from-reg with register number to-reg. */
4706 "This target hook should returns @code{true} if the compiler is allowed to\n\
4707 try to replace register number @var{from_reg} with register number\n\
4708 @var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
4709 is defined, and will usually be @code{true}, since most of the cases\n\
4710 preventing register elimination are things that the compiler already\n\
4713 Default return value is @code{true}.",
4714 bool, (const int from_reg, const int to_reg),
4715 hook_bool_const_int_const_int_true)
4717 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
4718 reg_names, and reg_class_contents to account of the vagaries of the
4721 (conditional_register_usage,
4722 "This hook may conditionally modify five variables\n\
4723 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
4724 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
4725 any dependence of these register sets on target flags. The first three\n\
4726 of these are of type @code{char []} (interpreted as Boolean vectors).\n\
4727 @code{global_regs} is a @code{const char *[]}, and\n\
4728 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
4729 called, @code{fixed_regs}, @code{call_used_regs},\n\
4730 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
4731 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
4732 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
4733 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
4734 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
4735 command options have been applied.\n\
4737 @cindex disabling certain registers\n\
4738 @cindex controlling register usage\n\
4739 If the usage of an entire class of registers depends on the target\n\
4740 flags, you may indicate this to GCC by using this macro to modify\n\
4741 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
4742 registers in the classes which should not be used by GCC@. Also make\n\
4743 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
4744 that shouldn't be used.\n\
4746 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
4747 of the insn patterns whose constraints permit this class are\n\
4748 controlled by target switches, then GCC will automatically avoid using\n\
4749 these registers when the target switches are opposed to them.)",
4753 /* Functions specific to the C family of frontends. */
4755 #define HOOK_PREFIX "TARGET_C_"
4756 HOOK_VECTOR (TARGET_C, c)
4758 /* ??? Documenting this hook requires a GFDL license grant. */
4761 "Return machine mode for non-standard constant literal suffix @var{c},\
4762 or VOIDmode if non-standard suffixes are unsupported.",
4763 enum machine_mode, (char c),
4764 default_mode_for_suffix)
4768 /* Functions specific to the C++ frontend. */
4770 #define HOOK_PREFIX "TARGET_CXX_"
4771 HOOK_VECTOR (TARGET_CXX, cxx)
4773 /* Return the integer type used for guard variables. */
4776 "Define this hook to override the integer type used for guard variables.\n\
4777 These are used to implement one-time construction of static objects. The\n\
4778 default is long_long_integer_type_node.",
4780 default_cxx_guard_type)
4782 /* Return true if only the low bit of the guard should be tested. */
4785 "This hook determines how guard variables are used. It should return\n\
4786 @code{false} (the default) if the first byte should be used. A return value of\n\
4787 @code{true} indicates that only the least significant bit should be used.",
4789 hook_bool_void_false)
4791 /* Returns the size of the array cookie for an array of type. */
4794 "This hook returns the size of the cookie to use when allocating an array\n\
4795 whose elements have the indicated @var{type}. Assumes that it is already\n\
4796 known that a cookie is needed. The default is\n\
4797 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
4798 IA64/Generic C++ ABI@.",
4800 default_cxx_get_cookie_size)
4802 /* Returns true if the element size should be stored in the array cookie. */
4805 "This hook should return @code{true} if the element size should be stored in\n\
4806 array cookies. The default is to return @code{false}.",
4808 hook_bool_void_false)
4810 /* Allows backends to perform additional processing when
4811 deciding if a class should be exported or imported. */
4813 (import_export_class,
4814 "If defined by a backend this hook allows the decision made to export\n\
4815 class @var{type} to be overruled. Upon entry @var{import_export}\n\
4816 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
4817 to be imported and 0 otherwise. This function should return the\n\
4818 modified value and perform any other actions necessary to support the\n\
4819 backend's targeted operating system.",
4820 int, (tree type, int import_export), NULL)
4822 /* Returns true if constructors and destructors return "this". */
4824 (cdtor_returns_this,
4825 "This hook should return @code{true} if constructors and destructors return\n\
4826 the address of the object created/destroyed. The default is to return\n\
4829 hook_bool_void_false)
4831 /* Returns true if the key method for a class can be an inline
4832 function, so long as it is not declared inline in the class
4833 itself. Returning true is the behavior required by the Itanium C++ ABI. */
4835 (key_method_may_be_inline,
4836 "This hook returns true if the key method for a class (i.e., the method\n\
4837 which, if defined in the current translation unit, causes the virtual\n\
4838 table to be emitted) may be an inline function. Under the standard\n\
4839 Itanium C++ ABI the key method may be an inline function so long as\n\
4840 the function is not declared inline in the class definition. Under\n\
4841 some variants of the ABI, an inline function can never be the key\n\
4842 method. The default is to return @code{true}.",
4844 hook_bool_void_true)
4847 (determine_class_data_visibility,
4848 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
4849 or other similar implicit class data object that will be emitted with\
4850 external linkage in this translation unit. No ELF visibility has been\
4851 explicitly specified. If the target needs to specify a visibility\
4852 other than that of the containing class, use this hook to set\
4853 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
4857 /* Returns true (the default) if virtual tables and other
4858 similar implicit class data objects are always COMDAT if they
4859 have external linkage. If this hook returns false, then
4860 class data for classes whose virtual table will be emitted in
4861 only one translation unit will not be COMDAT. */
4863 (class_data_always_comdat,
4864 "This hook returns true (the default) if virtual tables and other\n\
4865 similar implicit class data objects are always COMDAT if they have\n\
4866 external linkage. If this hook returns false, then class data for\n\
4867 classes whose virtual table will be emitted in only one translation\n\
4868 unit will not be COMDAT.",
4870 hook_bool_void_true)
4872 /* Returns true (the default) if the RTTI for the basic types,
4873 which is always defined in the C++ runtime, should be COMDAT;
4874 false if it should not be COMDAT. */
4876 (library_rtti_comdat,
4877 "This hook returns true (the default) if the RTTI information for\n\
4878 the basic types which is defined in the C++ runtime should always\n\
4879 be COMDAT, false if it should not be COMDAT.",
4881 hook_bool_void_true)
4883 /* Returns true if __aeabi_atexit should be used to register static
4887 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
4888 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
4889 is in effect. The default is to return false to use @code{__cxa_atexit}.",
4891 hook_bool_void_false)
4893 /* Returns true if target may use atexit in the same manner as
4894 __cxa_atexit to register static destructors. */
4896 (use_atexit_for_cxa_atexit,
4897 "This hook returns true if the target @code{atexit} function can be used\n\
4898 in the same manner as @code{__cxa_atexit} to register C++ static\n\
4899 destructors. This requires that @code{atexit}-registered functions in\n\
4900 shared libraries are run in the correct order when the libraries are\n\
4901 unloaded. The default is to return false.",
4903 hook_bool_void_false)
4906 (adjust_class_at_definition,
4907 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
4908 been defined. Use this hook to make adjustments to the class (eg, tweak\
4909 visibility or perform any other required target modifications).",
4914 (decl_mangling_context,
4915 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
4916 tree, (const_tree decl),
4917 hook_tree_const_tree_null)
4919 HOOK_VECTOR_END (cxx)
4921 /* Functions and data for emulated TLS support. */
4923 #define HOOK_PREFIX "TARGET_EMUTLS_"
4924 HOOK_VECTOR (TARGET_EMUTLS, emutls)
4926 /* Name of the address and common functions. */
4929 "Contains the name of the helper function that uses a TLS control\n\
4930 object to locate a TLS instance. The default causes libgcc's\n\
4931 emulated TLS helper function to be used.",
4932 const char *, "__builtin___emutls_get_address")
4936 "Contains the name of the helper function that should be used at\n\
4937 program startup to register TLS objects that are implicitly\n\
4938 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
4939 have explicit initializers. The default causes libgcc's emulated TLS\n\
4940 registration function to be used.",
4941 const char *, "__builtin___emutls_register_common")
4943 /* Prefixes for proxy variable and template. */
4946 "Contains the name of the section in which TLS control variables should\n\
4947 be placed. The default of @code{NULL} allows these to be placed in\n\
4953 "Contains the name of the section in which TLS initializers should be\n\
4954 placed. The default of @code{NULL} allows these to be placed in any\n\
4958 /* Prefixes for proxy variable and template. */
4961 "Contains the prefix to be prepended to TLS control variable names.\n\
4962 The default of @code{NULL} uses a target-specific prefix.",
4967 "Contains the prefix to be prepended to TLS initializer objects. The\n\
4968 default of @code{NULL} uses a target-specific prefix.",
4971 /* Function to generate field definitions of the proxy variable. */
4974 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
4975 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
4976 @var{name} should be filled with the structure tag, if the default of\n\
4977 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
4978 for libgcc's emulated TLS function.",
4979 tree, (tree type, tree *name),
4980 default_emutls_var_fields)
4982 /* Function to initialize a proxy variable. */
4985 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
4986 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
4987 is the TLS object and @var{tmpl_addr} is the address of the\n\
4988 initializer. The default initializes libgcc's emulated TLS control object.",
4989 tree, (tree var, tree decl, tree tmpl_addr),
4990 default_emutls_var_init)
4992 /* Whether we are allowed to alter the usual alignment of the
4996 "Specifies whether the alignment of TLS control variable objects is\n\
4997 fixed and should not be increased as some backends may do to optimize\n\
4998 single objects. The default is false.",
5001 /* Whether we can emit debug information for TLS vars. */
5003 (debug_form_tls_address,
5004 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5005 may be used to describe emulated TLS control objects.",
5008 HOOK_VECTOR_END (emutls)
5011 #define HOOK_PREFIX "TARGET_OPTION_"
5012 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5014 /* Function to validate the attribute((target(...))) strings. If
5015 the option is validated, the hook should also fill in
5016 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
5019 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5020 allows setting target-specific options on individual functions.\n\
5021 These function-specific options may differ\n\
5022 from the options specified on the command line. The hook should return\n\
5023 @code{true} if the options are valid.\n\
5025 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5026 the function declaration to hold a pointer to a target-specific\n\
5027 @code{struct cl_target_option} structure.",
5028 bool, (tree fndecl, tree name, tree args, int flags),
5029 default_target_option_valid_attribute_p)
5031 /* Function to save any extra target state in the target options structure. */
5034 "This hook is called to save any additional target-specific information\n\
5035 in the @code{struct cl_target_option} structure for function-specific\n\
5036 options from the @code{struct gcc_options} structure.\n\
5037 @xref{Option file format}.",
5038 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5040 /* Function to restore any extra target state from the target options
5044 "This hook is called to restore any additional target-specific\n\
5045 information in the @code{struct cl_target_option} structure for\n\
5046 function-specific options to the @code{struct gcc_options} structure.",
5047 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5049 /* Function to print any extra target state from the target options
5053 "This hook is called to print any additional target-specific\n\
5054 information in the @code{struct cl_target_option} structure for\n\
5055 function-specific options.",
5056 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5058 /* Function to parse arguments to be validated for #pragma target, and to
5059 change the state if the options are valid. If the first argument is
5060 NULL, the second argument specifies the default options to use. Return
5061 true if the options are valid, and set the current state. */
5064 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5065 sets the target-specific options for functions that occur later in the\n\
5066 input stream. The options accepted should be the same as those handled by the\n\
5067 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5068 bool, (tree args, tree pop_target),
5069 default_target_option_pragma_parse)
5071 /* Do option overrides for the target. */
5074 "Sometimes certain combinations of command options do not make sense on\n\
5075 a particular target machine. You can override the hook\n\
5076 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5077 once just after all the command options have been parsed.\n\
5079 Don't use this hook to turn on various extra optimizations for\n\
5080 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5082 If you need to do something whenever the optimization level is\n\
5083 changed via the optimize attribute or pragma, see\n\
5084 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5088 /* This function returns true if DECL1 and DECL2 are versions of the same
5089 function. DECL1 and DECL2 are function versions if and only if they
5090 have the same function signature and different target specific attributes,
5091 that is, they are compiled for different target machines. */
5094 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5095 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5096 versions if and only if they have the same function signature and\n\
5097 different target specific attributes, that is, they are compiled for\n\
5098 different target machines.",
5099 bool, (tree decl1, tree decl2),
5100 hook_bool_tree_tree_false)
5102 /* Function to determine if one function can inline another function. */
5104 #define HOOK_PREFIX "TARGET_"
5107 "This target hook returns @code{false} if the @var{caller} function\n\
5108 cannot inline @var{callee}, based on target specific information. By\n\
5109 default, inlining is not allowed if the callee function has function\n\
5110 specific target options and the caller does not use the same options.",
5111 bool, (tree caller, tree callee),
5112 default_target_can_inline_p)
5114 HOOK_VECTOR_END (target_option)
5116 /* For targets that need to mark extra registers as live on entry to
5117 the function, they should define this target hook and set their
5118 bits in the bitmap passed in. */
5120 (extra_live_on_entry,
5121 "Add any hard registers to @var{regs} that are live on entry to the\n\
5122 function. This hook only needs to be defined to provide registers that\n\
5123 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5124 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5125 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5126 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5127 void, (bitmap regs),
5130 /* Targets should define this target hook to mark that non-callee clobbers are
5131 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
5134 (call_fusage_contains_non_callee_clobbers,
5135 "Set to true if each call that binds to a local definition explicitly\n\
5136 clobbers or sets all non-fixed registers modified by performing the call.\n\
5137 That is, by the call pattern itself, or by code that might be inserted by the\n\
5138 linker (e.g. stubs, veneers, branch islands), but not including those\n\
5139 modifiable by the callee. The affected registers may be mentioned explicitly\n\
5140 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
5141 The default version of this hook is set to false. The purpose of this hook\n\
5142 is to enable the fuse-caller-save optimization.",
5146 /* Fill in additional registers set up by prologue into a regset. */
5148 (set_up_by_prologue,
5149 "This hook should add additional registers that are computed by the prologue\
5150 to the hard regset for shrink-wrapping optimization purposes.",
5151 void, (struct hard_reg_set_container *),
5154 /* For targets that have attributes that can affect whether a
5155 function's return statements need checking. For instance a 'naked'
5156 function attribute. */
5159 "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.",
5161 hook_bool_tree_true)
5163 /* Determine the type of unwind info to emit for debugging. */
5166 "This hook defines the mechanism that will be used for describing frame\n\
5167 unwind information to the debugger. Normally the hook will return\n\
5168 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5169 return @code{UI_NONE} otherwise.\n\
5171 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5172 is disabled in order to always output DWARF 2 frame information.\n\
5174 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5175 This will suppress generation of the normal debug frame unwind information.",
5176 enum unwind_info_type, (void),
5177 default_debug_unwind_info)
5179 /* The code parameter should be of type enum rtx_code but this is not
5180 defined at this time. */
5182 (canonicalize_comparison,
5183 "On some machines not all possible comparisons are defined, but you can\n\
5184 convert an invalid comparison into a valid one. For example, the Alpha\n\
5185 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5186 comparison instead and swap the order of the operands.\n\
5188 On such machines, implement this hook to do any required conversions.\n\
5189 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5190 are the left and right operands of the comparison, respectively. If\n\
5191 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5192 allowed to change the value of @var{op0} since the value might be used\n\
5193 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5194 allowed to swap operands in that case.\n\
5196 GCC will not assume that the comparison resulting from this macro is\n\
5197 valid but will see if the resulting insn matches a pattern in the\n\
5200 You need not to implement this hook if it would never change the\n\
5201 comparison code or operands.",
5202 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5203 default_canonicalize_comparison)
5206 (atomic_test_and_set_trueval,
5207 "This value should be set if the result written by\
5208 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5209 @code{bool} @code{true}.",
5212 /* Return an unsigned int representing the alignment (in bits) of the atomic
5213 type which maps to machine MODE. This allows alignment to be overridden
5216 (atomic_align_for_mode,
5217 "If defined, this function returns an appropriate alignment in bits for an\
5218 atomic object of machine_mode @var{mode}. If 0 is returned then the\
5219 default alignment for the specified mode is used. ",
5220 unsigned int, (enum machine_mode mode),
5224 (atomic_assign_expand_fenv,
5225 "ISO C11 requires atomic compound assignments that may raise floating-point\
5226 exceptions to raise exceptions corresponding to the arithmetic operation\
5227 whose result was successfully stored in a compare-and-exchange sequence. \
5228 This requires code equivalent to calls to @code{feholdexcept},\
5229 @code{feclearexcept} and @code{feupdateenv} to be generated at\
5230 appropriate points in the compare-and-exchange sequence. This hook should\
5231 set @code{*@var{hold}} to an expression equivalent to the call to\
5232 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
5233 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
5234 equivalent to the call to @code{feupdateenv}. The three expressions are\
5235 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
5236 if no code is required in a particular place. The default implementation\
5237 leaves all three expressions as @code{NULL_TREE}. The\
5238 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
5239 as part of the code generated in @code{*@var{update}}.",
5240 void, (tree *hold, tree *clear, tree *update),
5241 default_atomic_assign_expand_fenv)
5243 /* Leave the boolean fields at the end. */
5245 /* True if we can create zeroed data by switching to a BSS section
5246 and then using ASM_OUTPUT_SKIP to allocate the space. */
5248 (have_switchable_bss_sections,
5249 "This flag is true if we can create zeroed data by switching to a BSS\n\
5250 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5251 This is true on most ELF targets.",
5254 /* True if "native" constructors and destructors are supported,
5255 false if we're using collect2 for the job. */
5258 "This value is true if the target supports some ``native'' method of\n\
5259 collecting constructors and destructors to be run at startup and exit.\n\
5260 It is false if we must use @command{collect2}.",
5263 /* True if thread-local storage is supported. */
5266 "Contains the value true if the target supports thread-local storage.\n\
5267 The default value is false.",
5270 /* True if a small readonly data section is supported. */
5272 (have_srodata_section,
5273 "Contains the value true if the target places read-only\n\
5274 ``small data'' into a separate section. The default value is false.",
5277 /* True if EH frame info sections should be zero-terminated. */
5279 (terminate_dw2_eh_frame_info,
5280 "Contains the value true if the target should add a zero word onto the\n\
5281 end of a Dwarf-2 frame info section when used for exception handling.\n\
5282 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5286 /* True if #NO_APP should be emitted at the beginning of assembly output. */
5288 (asm_file_start_app_off,
5289 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5290 printed as the very first line in the assembly file, unless\n\
5291 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
5292 to the empty string, this variable has no effect.) With the normal\n\
5293 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5294 assembler that it need not bother stripping comments or extra\n\
5295 whitespace from its input. This allows it to work a bit faster.\n\
5297 The default is false. You should not set it to true unless you have\n\
5298 verified that your port does not generate any extra whitespace or\n\
5299 comments that will cause GAS to issue errors in NO_APP mode.",
5302 /* True if output_file_directive should be called for main_input_filename
5303 at the beginning of assembly output. */
5305 (asm_file_start_file_directive,
5306 "If this flag is true, @code{output_file_directive} will be called\n\
5307 for the primary source file, immediately after printing\n\
5308 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
5309 this to be done. The default is false.",
5312 /* True if the target is allowed to reorder memory accesses unless
5313 synchronization is explicitly requested. */
5316 "If set to @code{true}, means that the target's memory model does not\n\
5317 guarantee that loads which do not depend on one another will access\n\
5318 main memory in the order of the instruction stream; if ordering is\n\
5319 important, an explicit memory barrier must be used. This is true of\n\
5320 many recent processors which implement a policy of ``relaxed,''\n\
5321 ``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,\n\
5322 and ia64. The default is @code{false}.",
5325 /* Returns true if we should generate exception tables for use with the
5326 ARM EABI. The effects the encoding of function exception specifications. */
5329 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5330 based unwinding library, and @code{false} on other targets. This effects\n\
5331 the format of unwinding tables, and how the unwinder in entered after\n\
5332 running a cleanup. The default is @code{false}.",
5336 (want_debug_pub_sections,
5337 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5338 should be emitted. These sections are not used on most platforms, and\
5339 in particular GDB does not use them.",
5344 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5345 compilation unit. This attribute is required for the darwin linker \
5346 to emit debug information.",
5350 (delay_sched2, "True if sched2 is not to be run at its normal place. \
5351 This usually means it will be run as part of machine-specific reorg.",
5355 (delay_vartrack, "True if vartrack is not to be run at its normal place. \
5356 This usually means it will be run as part of machine-specific reorg.",
5359 /* Leave the boolean fields at the end. */
5361 /* Functions related to mode switching. */
5363 #define HOOK_PREFIX "TARGET_MODE_"
5364 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
5368 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
5369 void, (int entity, int mode, HARD_REG_SET regs_live), NULL)
5373 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
5374 int, (int entity, rtx insn), NULL)
5378 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
5379 int, (int entity, int mode, rtx insn), NULL)
5383 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
5384 int, (int entity), NULL)
5388 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
5389 int, (int entity), NULL)
5393 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
5394 int, (int entity, int n), NULL)
5396 HOOK_VECTOR_END (mode_switching)
5398 /* Close the 'struct gcc_target' definition. */
5399 HOOK_VECTOR_END (C90_EMPTY_HACK)