2002-05-04 David S. Miller <davem@redhat.com>
[official-gcc.git] / gcc / function.h
blob70164f1d9fad72c90e02baaae2bcd4d03d6668a6
1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
22 struct var_refs_queue
24 rtx modified;
25 enum machine_mode promoted_mode;
26 int unsignedp;
27 struct var_refs_queue *next;
30 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
31 Each element describes one pending sequence.
32 The main insn-chain is saved in the last element of the chain,
33 unless the chain is empty. */
35 struct sequence_stack
37 /* First and last insns in the chain of the saved sequence. */
38 rtx first, last;
39 tree sequence_rtl_expr;
40 struct sequence_stack *next;
43 extern struct sequence_stack *sequence_stack;
45 /* Stack of single obstacks. */
47 struct simple_obstack_stack
49 struct obstack *obstack;
50 struct simple_obstack_stack *next;
53 struct emit_status
55 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
56 After rtl generation, it is 1 plus the largest register number used. */
57 int x_reg_rtx_no;
59 /* Lowest label number in current function. */
60 int x_first_label_num;
62 /* The ends of the doubly-linked chain of rtl for the current function.
63 Both are reset to null at the start of rtl generation for the function.
65 start_sequence saves both of these on `sequence_stack' along with
66 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
67 rtx x_first_insn;
68 rtx x_last_insn;
70 /* RTL_EXPR within which the current sequence will be placed. Use to
71 prevent reuse of any temporaries within the sequence until after the
72 RTL_EXPR is emitted. */
73 tree sequence_rtl_expr;
75 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
76 Each element describes one pending sequence.
77 The main insn-chain is saved in the last element of the chain,
78 unless the chain is empty. */
79 struct sequence_stack *sequence_stack;
81 /* INSN_UID for next insn emitted.
82 Reset to 1 for each function compiled. */
83 int x_cur_insn_uid;
85 /* Line number and source file of the last line-number NOTE emitted.
86 This is used to avoid generating duplicates. */
87 int x_last_linenum;
88 const char *x_last_filename;
90 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
91 vectors. Since these vectors are needed during the expansion phase when
92 the total number of registers in the function is not yet known, the
93 vectors are copied and made bigger when necessary. */
94 int regno_pointer_align_length;
96 /* Indexed by pseudo register number, if nonzero gives the known alignment
97 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
98 Allocated in parallel with x_regno_reg_rtx. */
99 unsigned char *regno_pointer_align;
101 /* Indexed by pseudo register number, if nonzero gives the decl
102 corresponding to that register. */
103 tree *regno_decl;
105 /* Indexed by pseudo register number, gives the rtx for that pseudo.
106 Allocated in parallel with regno_pointer_align. */
107 rtx *x_regno_reg_rtx;
110 /* For backward compatibility... eventually these should all go away. */
111 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
112 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
113 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
114 #define seq_stack (cfun->emit->sequence_stack)
116 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
117 #define REGNO_DECL(REGNO) (cfun->emit->regno_decl[REGNO])
119 struct expr_status
121 /* Number of units that we should eventually pop off the stack.
122 These are the arguments to function calls that have already returned. */
123 int x_pending_stack_adjust;
125 /* Under some ABIs, it is the caller's responsibility to pop arguments
126 pushed for function calls. A naive implementation would simply pop
127 the arguments immediately after each call. However, if several
128 function calls are made in a row, it is typically cheaper to pop
129 all the arguments after all of the calls are complete since a
130 single pop instruction can be used. Therefore, GCC attempts to
131 defer popping the arguments until absolutely necessary. (For
132 example, at the end of a conditional, the arguments must be popped,
133 since code outside the conditional won't know whether or not the
134 arguments need to be popped.)
136 When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
137 attempt to defer pops. Instead, the stack is popped immediately
138 after each call. Rather then setting this variable directly, use
139 NO_DEFER_POP and OK_DEFER_POP. */
140 int x_inhibit_defer_pop;
142 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
143 boundary can be momentarily unaligned while pushing the arguments.
144 Record the delta since last aligned boundary here in order to get
145 stack alignment in the nested function calls working right. */
146 int x_stack_pointer_delta;
148 /* Nonzero means __builtin_saveregs has already been done in this function.
149 The value is the pseudoreg containing the value __builtin_saveregs
150 returned. */
151 rtx x_saveregs_value;
153 /* Similarly for __builtin_apply_args. */
154 rtx x_apply_args_value;
156 /* List of labels that must never be deleted. */
157 rtx x_forced_labels;
159 /* Postincrements that still need to be expanded. */
160 rtx x_pending_chain;
163 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
164 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
165 #define saveregs_value (cfun->expr->x_saveregs_value)
166 #define apply_args_value (cfun->expr->x_apply_args_value)
167 #define forced_labels (cfun->expr->x_forced_labels)
168 #define pending_chain (cfun->expr->x_pending_chain)
169 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
171 /* This structure can save all the important global and static variables
172 describing the status of the current function. */
174 struct function
176 struct eh_status *eh;
177 struct stmt_status *stmt;
178 struct expr_status *expr;
179 struct emit_status *emit;
180 struct varasm_status *varasm;
182 /* For function.c. */
184 /* Name of this function. */
185 const char *name;
187 /* Points to the FUNCTION_DECL of this function. */
188 tree decl;
190 /* Function containing this function, if any. */
191 struct function *outer;
193 /* Number of bytes of args popped by function being compiled on its return.
194 Zero if no bytes are to be popped.
195 May affect compilation of return insn or of function epilogue. */
196 int pops_args;
198 /* If function's args have a fixed size, this is that size, in bytes.
199 Otherwise, it is -1.
200 May affect compilation of return insn or of function epilogue. */
201 int args_size;
203 /* # bytes the prologue should push and pretend that the caller pushed them.
204 The prologue must do this, but only if parms can be passed in
205 registers. */
206 int pretend_args_size;
208 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
209 defined, the needed space is pushed by the prologue. */
210 int outgoing_args_size;
212 /* This is the offset from the arg pointer to the place where the first
213 anonymous arg can be found, if there is one. */
214 rtx arg_offset_rtx;
216 /* Quantities of various kinds of registers
217 used for the current function's args. */
218 CUMULATIVE_ARGS args_info;
220 /* If non-zero, an RTL expression for the location at which the current
221 function returns its result. If the current function returns its
222 result in a register, current_function_return_rtx will always be
223 the hard register containing the result. */
224 rtx return_rtx;
226 /* The arg pointer hard register, or the pseudo into which it was copied. */
227 rtx internal_arg_pointer;
229 /* Language-specific reason why the current function cannot be made
230 inline. */
231 const char *cannot_inline;
233 /* Opaque pointer used by get_hard_reg_initial_val and
234 has_hard_reg_initial_val (see integrate.[hc]). */
235 struct initial_value_struct *hard_reg_initial_vals;
237 /* Number of function calls seen so far in current function. */
238 int x_function_call_count;
240 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
241 (labels to which there can be nonlocal gotos from nested functions)
242 in this function. */
243 tree x_nonlocal_labels;
245 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
246 for nonlocal gotos. There is one for every nonlocal label in the
247 function; this list matches the one in nonlocal_labels.
248 Zero when function does not have nonlocal labels. */
249 rtx x_nonlocal_goto_handler_slots;
251 /* List (chain of EXPR_LIST) of labels heading the current handlers for
252 nonlocal gotos. */
253 rtx x_nonlocal_goto_handler_labels;
255 /* RTX for stack slot that holds the stack pointer value to restore
256 for a nonlocal goto.
257 Zero when function does not have nonlocal labels. */
258 rtx x_nonlocal_goto_stack_level;
260 /* Label that will go on parm cleanup code, if any.
261 Jumping to this label runs cleanup code for parameters, if
262 such code must be run. Following this code is the logical return
263 label. */
264 rtx x_cleanup_label;
266 /* Label that will go on function epilogue.
267 Jumping to this label serves as a "return" instruction
268 on machines which require execution of the epilogue on all returns. */
269 rtx x_return_label;
271 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
272 So we can mark them all live at the end of the function, if nonopt. */
273 rtx x_save_expr_regs;
275 /* List (chain of EXPR_LISTs) of all stack slots in this function.
276 Made for the sake of unshare_all_rtl. */
277 rtx x_stack_slot_list;
279 /* Chain of all RTL_EXPRs that have insns in them. */
280 tree x_rtl_expr_chain;
282 /* Label to jump back to for tail recursion, or 0 if we have
283 not yet needed one for this function. */
284 rtx x_tail_recursion_label;
286 /* Place after which to insert the tail_recursion_label if we need one. */
287 rtx x_tail_recursion_reentry;
289 /* Location at which to save the argument pointer if it will need to be
290 referenced. There are two cases where this is done: if nonlocal gotos
291 exist, or if vars stored at an offset from the argument pointer will be
292 needed by inner routines. */
293 rtx x_arg_pointer_save_area;
295 /* If the function returns non-void, we will emit a clobber of the
296 return registers just in case the user fell off the end without
297 returning a proper value. This is that insn. */
298 rtx x_clobber_return_insn;
300 /* Offset to end of allocated area of stack frame.
301 If stack grows down, this is the address of the last stack slot allocated.
302 If stack grows up, this is the address for the next slot. */
303 HOST_WIDE_INT x_frame_offset;
305 /* List (chain of TREE_LISTs) of static chains for containing functions.
306 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
307 in an RTL_EXPR in the TREE_VALUE. */
308 tree x_context_display;
310 /* List (chain of TREE_LISTs) of trampolines for nested functions.
311 The trampoline sets up the static chain and jumps to the function.
312 We supply the trampoline's address when the function's address is
313 requested.
315 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
316 in an RTL_EXPR in the TREE_VALUE. */
317 tree x_trampoline_list;
319 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
320 rtx x_parm_birth_insn;
322 /* Last insn of those whose job was to put parms into their nominal
323 homes. */
324 rtx x_last_parm_insn;
326 /* 1 + last pseudo register number possibly used for loading a copy
327 of a parameter of this function. */
328 unsigned int x_max_parm_reg;
330 /* Vector indexed by REGNO, containing location on stack in which
331 to put the parm which is nominally in pseudo register REGNO,
332 if we discover that that parm must go in the stack. The highest
333 element in this vector is one less than MAX_PARM_REG, above. */
334 rtx *x_parm_reg_stack_loc;
336 /* List of all temporaries allocated, both available and in use. */
337 struct temp_slot *x_temp_slots;
339 /* Current nesting level for temporaries. */
340 int x_temp_slot_level;
342 /* Current nesting level for variables in a block. */
343 int x_var_temp_slot_level;
345 /* When temporaries are created by TARGET_EXPRs, they are created at
346 this level of temp_slot_level, so that they can remain allocated
347 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
348 of TARGET_EXPRs. */
349 int x_target_temp_slot_level;
351 /* This slot is initialized as 0 and is added to
352 during the nested function. */
353 struct var_refs_queue *fixup_var_refs_queue;
355 /* For integrate.c. */
356 int inlinable;
357 int no_debugging_symbols;
358 /* This is in fact an rtvec. */
359 void *original_arg_vector;
360 tree original_decl_initial;
361 /* Last insn of those whose job was to put parms into their nominal
362 homes. */
363 rtx inl_last_parm_insn;
364 /* Highest label number in current function. */
365 int inl_max_label_num;
367 /* Profile label number. */
368 int profile_label_no;
370 /* For md files. */
372 /* tm.h can use this to store whatever it likes. */
373 struct machine_function *machine;
374 /* The largest alignment of slot allocated on the stack. */
375 int stack_alignment_needed;
376 /* Preferred alignment of the end of stack frame. */
377 int preferred_stack_boundary;
379 /* Language-specific code can use this to store whatever it likes. */
380 struct language_function *language;
382 /* For reorg. */
384 /* If some insns can be deferred to the delay slots of the epilogue, the
385 delay list for them is recorded here. */
386 rtx epilogue_delay_list;
388 /* Collected bit flags. */
390 /* Nonzero if function being compiled needs to be given an address
391 where the value should be stored. */
392 unsigned int returns_struct : 1;
394 /* Nonzero if function being compiled needs to
395 return the address of where it has put a structure value. */
396 unsigned int returns_pcc_struct : 1;
398 /* Nonzero if the current function returns a pointer type. */
399 unsigned int returns_pointer : 1;
401 /* Nonzero if function being compiled needs to be passed a static chain. */
402 unsigned int needs_context : 1;
404 /* Nonzero if function being compiled can call setjmp. */
405 unsigned int calls_setjmp : 1;
407 /* Nonzero if function being compiled can call longjmp. */
408 unsigned int calls_longjmp : 1;
410 /* Nonzero if function being compiled can call alloca,
411 either as a subroutine or builtin. */
412 unsigned int calls_alloca : 1;
414 /* Nonzero if the function calls __builtin_eh_return. */
415 unsigned int calls_eh_return : 1;
417 /* Nonzero if function being compiled receives nonlocal gotos
418 from nested functions. */
419 unsigned int has_nonlocal_label : 1;
421 /* Nonzero if function being compiled has nonlocal gotos to parent
422 function. */
423 unsigned int has_nonlocal_goto : 1;
425 /* Nonzero if function being compiled contains nested functions. */
426 unsigned int contains_functions : 1;
428 /* Nonzero if the function being compiled issues a computed jump. */
429 unsigned int has_computed_jump : 1;
431 /* Nonzero if the current function is a thunk (a lightweight function that
432 just adjusts one of its arguments and forwards to another function), so
433 we should try to cut corners where we can. */
434 unsigned int is_thunk : 1;
436 /* Nonzero if instrumentation calls for function entry and exit should be
437 generated. */
438 unsigned int instrument_entry_exit : 1;
440 /* Nonzero if profiling code should be generated. */
441 unsigned int profile : 1;
443 /* Nonzero if stack limit checking should be enabled in the current
444 function. */
445 unsigned int limit_stack : 1;
447 /* Nonzero if current function uses varargs.h or equivalent.
448 Zero for functions that use stdarg.h. */
449 unsigned int varargs : 1;
451 /* Nonzero if current function uses stdarg.h or equivalent.
452 Zero for functions that use varargs.h. */
453 unsigned int stdarg : 1;
455 /* Nonzero if this function is being processed in function-at-a-time
456 mode. In other words, if all tree structure for this function,
457 including the BLOCK tree, is created before RTL generation
458 commences. */
459 unsigned int x_whole_function_mode_p : 1;
461 /* Nonzero if the back-end should not keep track of expressions that
462 determine the size of variable-sized objects. Normally, such
463 expressions are saved away, and then expanded when the next
464 function is started. For example, if a parameter has a
465 variable-sized type, then the size of the parameter is computed
466 when the function body is entered. However, some front-ends do
467 not desire this behavior. */
468 unsigned int x_dont_save_pending_sizes_p : 1;
470 /* Nonzero if the current function uses the constant pool. */
471 unsigned int uses_const_pool : 1;
473 /* Nonzero if the current function uses pic_offset_table_rtx. */
474 unsigned int uses_pic_offset_table : 1;
476 /* Nonzero if the current function needs an lsda for exception handling. */
477 unsigned int uses_eh_lsda : 1;
479 /* Nonzero if code to initialize arg_pointer_save_area has been emited. */
480 unsigned int arg_pointer_save_area_init : 1;
483 /* The function currently being compiled. */
484 extern struct function *cfun;
486 /* Nonzero if we've already converted virtual regs to hard regs. */
487 extern int virtuals_instantiated;
489 /* For backward compatibility... eventually these should all go away. */
490 #define current_function_name (cfun->name)
491 #define current_function_pops_args (cfun->pops_args)
492 #define current_function_returns_struct (cfun->returns_struct)
493 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
494 #define current_function_returns_pointer (cfun->returns_pointer)
495 #define current_function_needs_context (cfun->needs_context)
496 #define current_function_calls_setjmp (cfun->calls_setjmp)
497 #define current_function_calls_alloca (cfun->calls_alloca)
498 #define current_function_calls_longjmp (cfun->calls_longjmp)
499 #define current_function_calls_eh_return (cfun->calls_eh_return)
500 #define current_function_has_computed_jump (cfun->has_computed_jump)
501 #define current_function_contains_functions (cfun->contains_functions)
502 #define current_function_is_thunk (cfun->is_thunk)
503 #define current_function_args_info (cfun->args_info)
504 #define current_function_args_size (cfun->args_size)
505 #define current_function_pretend_args_size (cfun->pretend_args_size)
506 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
507 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
508 #define current_function_varargs (cfun->varargs)
509 #define current_function_stdarg (cfun->stdarg)
510 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
511 #define current_function_return_rtx (cfun->return_rtx)
512 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
513 #define current_function_profile (cfun->profile)
514 #define current_function_profile_label_no (cfun->profile_label_no)
515 #define current_function_limit_stack (cfun->limit_stack)
516 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
517 #define current_function_uses_const_pool (cfun->uses_const_pool)
518 #define current_function_cannot_inline (cfun->cannot_inline)
519 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
520 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
521 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
523 #define max_parm_reg (cfun->x_max_parm_reg)
524 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
525 #define cleanup_label (cfun->x_cleanup_label)
526 #define return_label (cfun->x_return_label)
527 #define save_expr_regs (cfun->x_save_expr_regs)
528 #define stack_slot_list (cfun->x_stack_slot_list)
529 #define parm_birth_insn (cfun->x_parm_birth_insn)
530 #define frame_offset (cfun->x_frame_offset)
531 #define tail_recursion_label (cfun->x_tail_recursion_label)
532 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
533 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
534 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
535 #define last_parm_insn (cfun->x_last_parm_insn)
536 #define context_display (cfun->x_context_display)
537 #define trampoline_list (cfun->x_trampoline_list)
538 #define function_call_count (cfun->x_function_call_count)
539 #define temp_slots (cfun->x_temp_slots)
540 #define temp_slot_level (cfun->x_temp_slot_level)
541 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
542 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
543 #define nonlocal_labels (cfun->x_nonlocal_labels)
544 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
545 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
546 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
548 /* The FUNCTION_DECL for an inline function currently being expanded. */
549 extern tree inline_function_decl;
551 /* Given a function decl for a containing function,
552 return the `struct function' for it. */
553 struct function *find_function_data PARAMS ((tree));
555 /* Set NOTE_BLOCK for each block note in the current function. */
556 extern void identify_blocks PARAMS ((void));
558 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
559 and create duplicate blocks. */
560 extern void reorder_blocks PARAMS ((void));
562 /* Set BLOCK_NUMBER for all the blocks in FN. */
563 extern void number_blocks PARAMS ((tree));
565 /* Return size needed for stack frame based on slots so far allocated.
566 This size counts from zero. It is not rounded to STACK_BOUNDARY;
567 the caller may have to do that. */
568 extern HOST_WIDE_INT get_frame_size PARAMS ((void));
569 /* Likewise, but for a different than the current function. */
570 extern HOST_WIDE_INT get_func_frame_size PARAMS ((struct function *));
572 /* These variables hold pointers to functions to create and destroy
573 target specific, per-function data structures. */
574 extern void (*init_machine_status) PARAMS ((struct function *));
575 extern void (*free_machine_status) PARAMS ((struct function *));
576 /* This variable holds a pointer to a function to register any
577 data items in the target specific, per-function data structure
578 that will need garbage collection. */
579 extern void (*mark_machine_status) PARAMS ((struct function *));
581 /* Save and restore status information for a nested function. */
582 extern void restore_emit_status PARAMS ((struct function *));
583 extern void free_after_parsing PARAMS ((struct function *));
584 extern void free_after_compilation PARAMS ((struct function *));
586 extern void init_varasm_status PARAMS ((struct function *));
587 extern void free_varasm_status PARAMS ((struct function *));
588 extern void free_emit_status PARAMS ((struct function *));
589 extern void free_stmt_status PARAMS ((struct function *));
590 extern void free_eh_status PARAMS ((struct function *));
591 extern void free_expr_status PARAMS ((struct function *));
593 extern rtx get_first_block_beg PARAMS ((void));
595 #ifdef RTX_CODE
596 extern void diddle_return_value PARAMS ((void (*)(rtx, void*), void*));
597 extern void clobber_return_register PARAMS ((void));
598 extern void use_return_register PARAMS ((void));
599 #endif
601 extern rtx get_arg_pointer_save_area PARAMS ((struct function *));
603 extern void init_virtual_regs PARAMS ((struct emit_status *));
605 /* Called once, at initialization, to initialize function.c. */
606 extern void init_function_once PARAMS ((void));