2001-02-14 Tom Tromey <tromey@redhat.com>
[official-gcc.git] / gcc / function.h
blobc0aa0db1e93d7ef51b33f543436e6e28ac9d7541
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 GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 #if !defined(NULL_TREE) && !defined(tree)
24 typedef union union_node *_function_tree;
25 #define tree _function_tree
26 #endif
27 #if !defined(NULL_RTX) && !defined(rtx)
28 typedef struct rtx_def *_function_rtx;
29 #define rtx _function_rtx
30 #endif
32 struct var_refs_queue
34 rtx modified;
35 enum machine_mode promoted_mode;
36 int unsignedp;
37 struct var_refs_queue *next;
40 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
41 Each element describes one pending sequence.
42 The main insn-chain is saved in the last element of the chain,
43 unless the chain is empty. */
45 struct sequence_stack
47 /* First and last insns in the chain of the saved sequence. */
48 rtx first, last;
49 tree sequence_rtl_expr;
50 struct sequence_stack *next;
53 extern struct sequence_stack *sequence_stack;
55 /* Stack of single obstacks. */
57 struct simple_obstack_stack
59 struct obstack *obstack;
60 struct simple_obstack_stack *next;
63 struct emit_status
65 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
66 After rtl generation, it is 1 plus the largest register number used. */
67 int x_reg_rtx_no;
69 /* Lowest label number in current function. */
70 int x_first_label_num;
72 /* The ends of the doubly-linked chain of rtl for the current function.
73 Both are reset to null at the start of rtl generation for the function.
75 start_sequence saves both of these on `sequence_stack' along with
76 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
77 rtx x_first_insn;
78 rtx x_last_insn;
80 /* RTL_EXPR within which the current sequence will be placed. Use to
81 prevent reuse of any temporaries within the sequence until after the
82 RTL_EXPR is emitted. */
83 tree sequence_rtl_expr;
85 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
86 Each element describes one pending sequence.
87 The main insn-chain is saved in the last element of the chain,
88 unless the chain is empty. */
89 struct sequence_stack *sequence_stack;
91 /* INSN_UID for next insn emitted.
92 Reset to 1 for each function compiled. */
93 int x_cur_insn_uid;
95 /* Line number and source file of the last line-number NOTE emitted.
96 This is used to avoid generating duplicates. */
97 int x_last_linenum;
98 const char *x_last_filename;
100 /* The length of the regno_pointer_align and x_regno_reg_rtx vectors.
101 Since these vectors are needed during the expansion phase when
102 the total number of registers in the function is not yet known,
103 the vectors are copied and made bigger when necessary. */
104 int regno_pointer_align_length;
106 /* Indexed by pseudo register number, if nonzero gives the known alignment
107 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
108 Allocated in parallel with x_regno_reg_rtx. */
109 unsigned char *regno_pointer_align;
111 /* Indexed by pseudo register number, gives the rtx for that pseudo.
112 Allocated in parallel with regno_pointer_align. */
113 rtx *x_regno_reg_rtx;
116 /* For backward compatibility... eventually these should all go away. */
117 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
118 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
119 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
120 #define seq_stack (cfun->emit->sequence_stack)
122 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
124 struct expr_status
126 /* Number of units that we should eventually pop off the stack.
127 These are the arguments to function calls that have already returned. */
128 int x_pending_stack_adjust;
130 /* Under some ABIs, it is the caller's responsibility to pop arguments
131 pushed for function calls. A naive implementation would simply pop
132 the arguments immediately after each call. However, if several
133 function calls are made in a row, it is typically cheaper to pop
134 all the arguments after all of the calls are complete since a
135 single pop instruction can be used. Therefore, GCC attempts to
136 defer popping the arguments until absolutely necessary. (For
137 example, at the end of a conditional, the arguments must be popped,
138 since code outside the conditional won't know whether or not the
139 arguments need to be popped.)
141 When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
142 attempt to defer pops. Instead, the stack is popped immediately
143 after each call. Rather then setting this variable directly, use
144 NO_DEFER_POP and OK_DEFER_POP. */
145 int x_inhibit_defer_pop;
147 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
148 boundary can be momentairly unaligned while pushing the arguments.
149 Record the delta since last aligned boundary here in order to get
150 stack alignment in the nested function calls working right. */
151 int x_stack_pointer_delta;
153 /* Nonzero means __builtin_saveregs has already been done in this function.
154 The value is the pseudoreg containing the value __builtin_saveregs
155 returned. */
156 rtx x_saveregs_value;
158 /* Similarly for __builtin_apply_args. */
159 rtx x_apply_args_value;
161 /* List of labels that must never be deleted. */
162 rtx x_forced_labels;
164 /* Postincrements that still need to be expanded. */
165 rtx x_pending_chain;
168 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
169 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
170 #define saveregs_value (cfun->expr->x_saveregs_value)
171 #define apply_args_value (cfun->expr->x_apply_args_value)
172 #define forced_labels (cfun->expr->x_forced_labels)
173 #define pending_chain (cfun->expr->x_pending_chain)
174 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
176 /* This structure can save all the important global and static variables
177 describing the status of the current function. */
179 struct function
181 struct function *next_global;
182 struct function *next;
184 struct eh_status *eh;
185 struct stmt_status *stmt;
186 struct expr_status *expr;
187 struct emit_status *emit;
188 struct varasm_status *varasm;
190 /* For function.c. */
192 /* Name of this function. */
193 const char *name;
194 /* Points to the FUNCTION_DECL of this function. */
195 tree decl;
197 /* Number of bytes of args popped by function being compiled on its return.
198 Zero if no bytes are to be popped.
199 May affect compilation of return insn or of function epilogue. */
200 int pops_args;
202 /* Nonzero if function being compiled needs to be given an address
203 where the value should be stored. */
204 int returns_struct;
206 /* Nonzero if function being compiled needs to
207 return the address of where it has put a structure value. */
208 int returns_pcc_struct;
210 /* Nonzero if the current function returns a pointer type. */
211 int returns_pointer;
213 /* Nonzero if function being compiled needs to be passed a static chain. */
214 int needs_context;
216 /* Nonzero if function being compiled can call setjmp. */
217 int calls_setjmp;
219 /* Nonzero if function being compiled can call longjmp. */
220 int calls_longjmp;
222 /* Nonzero if function being compiled can call alloca,
223 either as a subroutine or builtin. */
224 int calls_alloca;
226 /* Nonzero if function being compiled receives nonlocal gotos
227 from nested functions. */
229 int has_nonlocal_label;
231 /* Nonzero if function being compiled has nonlocal gotos to parent
232 function. */
233 int has_nonlocal_goto;
235 /* Nonzero if function being compiled contains nested functions. */
236 int contains_functions;
238 /* Nonzero if the function being compiled issues a computed jump. */
239 int has_computed_jump;
241 /* Nonzero if the current function is a thunk (a lightweight function that
242 just adjusts one of its arguments and forwards to another function), so
243 we should try to cut corners where we can. */
244 int is_thunk;
246 /* If function's args have a fixed size, this is that size, in bytes.
247 Otherwise, it is -1.
248 May affect compilation of return insn or of function epilogue. */
249 int args_size;
251 /* # bytes the prologue should push and pretend that the caller pushed them.
252 The prologue must do this, but only if parms can be passed in
253 registers. */
254 int pretend_args_size;
256 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
257 defined, the needed space is pushed by the prologue. */
258 int outgoing_args_size;
260 /* This is the offset from the arg pointer to the place where the first
261 anonymous arg can be found, if there is one. */
262 rtx arg_offset_rtx;
264 /* Nonzero if current function uses varargs.h or equivalent.
265 Zero for functions that use stdarg.h. */
266 int varargs;
268 /* Nonzero if current function uses stdarg.h or equivalent.
269 Zero for functions that use varargs.h. */
270 int stdarg;
272 /* Quantities of various kinds of registers
273 used for the current function's args. */
274 CUMULATIVE_ARGS args_info;
276 /* If non-zero, an RTL expression for the location at which the current
277 function returns its result. If the current function returns its
278 result in a register, current_function_return_rtx will always be
279 the hard register containing the result. */
280 rtx return_rtx;
282 /* The arg pointer hard register, or the pseudo into which it was copied. */
283 rtx internal_arg_pointer;
285 /* Language-specific reason why the current function cannot be made
286 inline. */
287 const char *cannot_inline;
289 /* Nonzero if instrumentation calls for function entry and exit should be
290 generated. */
291 int instrument_entry_exit;
293 /* Nonzero if memory access checking be enabled in the current function. */
294 int check_memory_usage;
296 /* Nonzero if stack limit checking should be enabled in the current
297 function. */
298 int limit_stack;
300 /* Number of function calls seen so far in current function. */
301 int x_function_call_count;
303 /* Nonzero if this function is being processed in function-at-a-time
304 mode. In other words, if all tree structure for this function,
305 including the BLOCK tree, is created before RTL generation
306 commences. */
307 int x_whole_function_mode_p;
309 /* Nonzero if the back-end should not keep track of expressions that
310 determine the size of variable-sized objects. Normally, such
311 expressions are saved away, and then expanded when the next
312 function is started. For example, if a parameter has a
313 variable-sized type, then the size of the parameter is computed
314 when the function body is entered. However, some front-ends do
315 not desire this behavior. */
316 int x_dont_save_pending_sizes_p;
318 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
319 (labels to which there can be nonlocal gotos from nested functions)
320 in this function. */
321 tree x_nonlocal_labels;
323 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
324 for nonlocal gotos. There is one for every nonlocal label in the
325 function; this list matches the one in nonlocal_labels.
326 Zero when function does not have nonlocal labels. */
327 rtx x_nonlocal_goto_handler_slots;
329 /* List (chain of EXPR_LIST) of labels heading the current handlers for
330 nonlocal gotos. */
331 rtx x_nonlocal_goto_handler_labels;
333 /* RTX for stack slot that holds the stack pointer value to restore
334 for a nonlocal goto.
335 Zero when function does not have nonlocal labels. */
336 rtx x_nonlocal_goto_stack_level;
338 /* Label that will go on parm cleanup code, if any.
339 Jumping to this label runs cleanup code for parameters, if
340 such code must be run. Following this code is the logical return
341 label. */
342 rtx x_cleanup_label;
344 /* Label that will go on function epilogue.
345 Jumping to this label serves as a "return" instruction
346 on machines which require execution of the epilogue on all returns. */
347 rtx x_return_label;
349 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
350 So we can mark them all live at the end of the function, if nonopt. */
351 rtx x_save_expr_regs;
353 /* List (chain of EXPR_LISTs) of all stack slots in this function.
354 Made for the sake of unshare_all_rtl. */
355 rtx x_stack_slot_list;
357 /* Chain of all RTL_EXPRs that have insns in them. */
358 tree x_rtl_expr_chain;
360 /* Label to jump back to for tail recursion, or 0 if we have
361 not yet needed one for this function. */
362 rtx x_tail_recursion_label;
364 /* Place after which to insert the tail_recursion_label if we need one. */
365 rtx x_tail_recursion_reentry;
367 /* Location at which to save the argument pointer if it will need to be
368 referenced. There are two cases where this is done: if nonlocal gotos
369 exist, or if vars stored at an offset from the argument pointer will be
370 needed by inner routines. */
371 rtx x_arg_pointer_save_area;
373 /* If the function returns non-void, we will emit a clobber of the
374 return registers just in case the user fell off the end without
375 returning a proper value. This is that insn. */
376 rtx x_clobber_return_insn;
378 /* Offset to end of allocated area of stack frame.
379 If stack grows down, this is the address of the last stack slot allocated.
380 If stack grows up, this is the address for the next slot. */
381 HOST_WIDE_INT x_frame_offset;
383 /* List (chain of TREE_LISTs) of static chains for containing functions.
384 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
385 in an RTL_EXPR in the TREE_VALUE. */
386 tree x_context_display;
388 /* List (chain of TREE_LISTs) of trampolines for nested functions.
389 The trampoline sets up the static chain and jumps to the function.
390 We supply the trampoline's address when the function's address is
391 requested.
393 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
394 in an RTL_EXPR in the TREE_VALUE. */
395 tree x_trampoline_list;
397 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
398 rtx x_parm_birth_insn;
400 /* Last insn of those whose job was to put parms into their nominal
401 homes. */
402 rtx x_last_parm_insn;
404 /* 1 + last pseudo register number possibly used for loading a copy
405 of a parameter of this function. */
406 unsigned int x_max_parm_reg;
408 /* Vector indexed by REGNO, containing location on stack in which
409 to put the parm which is nominally in pseudo register REGNO,
410 if we discover that that parm must go in the stack. The highest
411 element in this vector is one less than MAX_PARM_REG, above. */
412 rtx *x_parm_reg_stack_loc;
414 /* List of all temporaries allocated, both available and in use. */
415 struct temp_slot *x_temp_slots;
417 /* Current nesting level for temporaries. */
418 int x_temp_slot_level;
420 /* Current nesting level for variables in a block. */
421 int x_var_temp_slot_level;
423 /* When temporaries are created by TARGET_EXPRs, they are created at
424 this level of temp_slot_level, so that they can remain allocated
425 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
426 of TARGET_EXPRs. */
427 int x_target_temp_slot_level;
429 /* This slot is initialized as 0 and is added to
430 during the nested function. */
431 struct var_refs_queue *fixup_var_refs_queue;
433 /* For integrate.c. */
434 int inlinable;
435 int no_debugging_symbols;
436 /* This is in fact an rtvec. */
437 void *original_arg_vector;
438 tree original_decl_initial;
439 /* Last insn of those whose job was to put parms into their nominal
440 homes. */
441 rtx inl_last_parm_insn;
442 /* Highest label number in current function. */
443 int inl_max_label_num;
445 /* Nonzero if the current function uses the constant pool. */
446 int uses_const_pool;
448 /* For md files. */
450 /* Nonzero if the current function uses pic_offset_table_rtx. */
451 int uses_pic_offset_table;
452 /* tm.h can use this to store whatever it likes. */
453 struct machine_function *machine;
454 /* The largest alignment of slot allocated on the stack. */
455 int stack_alignment_needed;
456 /* Preferred alignment of the end of stack frame. */
457 int preferred_stack_boundary;
459 /* Language-specific code can use this to store whatever it likes. */
460 struct language_function *language;
462 /* For reorg. */
464 /* If some insns can be deferred to the delay slots of the epilogue, the
465 delay list for them is recorded here. */
466 rtx epilogue_delay_list;
469 /* The function currently being compiled. */
470 extern struct function *cfun;
472 /* A list of all functions we have compiled so far. */
473 extern struct function *all_functions;
475 /* For backward compatibility... eventually these should all go away. */
476 #define current_function_name (cfun->name)
477 #define current_function_pops_args (cfun->pops_args)
478 #define current_function_returns_struct (cfun->returns_struct)
479 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
480 #define current_function_returns_pointer (cfun->returns_pointer)
481 #define current_function_needs_context (cfun->needs_context)
482 #define current_function_calls_setjmp (cfun->calls_setjmp)
483 #define current_function_calls_alloca (cfun->calls_alloca)
484 #define current_function_calls_longjmp (cfun->calls_longjmp)
485 #define current_function_has_computed_jump (cfun->has_computed_jump)
486 #define current_function_contains_functions (cfun->contains_functions)
487 #define current_function_is_thunk (cfun->is_thunk)
488 #define current_function_args_info (cfun->args_info)
489 #define current_function_args_size (cfun->args_size)
490 #define current_function_pretend_args_size (cfun->pretend_args_size)
491 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
492 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
493 #define current_function_varargs (cfun->varargs)
494 #define current_function_stdarg (cfun->stdarg)
495 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
496 #define current_function_return_rtx (cfun->return_rtx)
497 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
498 #define current_function_check_memory_usage (cfun->check_memory_usage)
499 #define current_function_limit_stack (cfun->limit_stack)
500 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
501 #define current_function_uses_const_pool (cfun->uses_const_pool)
502 #define current_function_cannot_inline (cfun->cannot_inline)
503 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
504 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
505 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
507 #define max_parm_reg (cfun->x_max_parm_reg)
508 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
509 #define cleanup_label (cfun->x_cleanup_label)
510 #define return_label (cfun->x_return_label)
511 #define save_expr_regs (cfun->x_save_expr_regs)
512 #define stack_slot_list (cfun->x_stack_slot_list)
513 #define parm_birth_insn (cfun->x_parm_birth_insn)
514 #define frame_offset (cfun->x_frame_offset)
515 #define tail_recursion_label (cfun->x_tail_recursion_label)
516 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
517 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
518 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
519 #define last_parm_insn (cfun->x_last_parm_insn)
520 #define context_display (cfun->x_context_display)
521 #define trampoline_list (cfun->x_trampoline_list)
522 #define function_call_count (cfun->x_function_call_count)
523 #define temp_slots (cfun->x_temp_slots)
524 #define temp_slot_level (cfun->x_temp_slot_level)
525 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
526 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
527 #define nonlocal_labels (cfun->x_nonlocal_labels)
528 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
529 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
530 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
532 /* The FUNCTION_DECL for an inline function currently being expanded. */
533 extern tree inline_function_decl;
535 /* Given a function decl for a containing function,
536 return the `struct function' for it. */
537 struct function *find_function_data PARAMS ((tree));
539 /* Pointer to chain of `struct function' for containing functions. */
540 extern struct function *outer_function_chain;
542 /* Set NOTE_BLOCK for each block note in the current function. */
543 extern void identify_blocks PARAMS ((void));
545 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
546 and create duplicate blocks. */
547 extern void reorder_blocks PARAMS ((void));
549 /* Set BLOCK_NUMBER for all the blocks in FN. */
550 extern void number_blocks PARAMS ((tree));
552 /* Return size needed for stack frame based on slots so far allocated.
553 This size counts from zero. It is not rounded to STACK_BOUNDARY;
554 the caller may have to do that. */
555 extern HOST_WIDE_INT get_frame_size PARAMS ((void));
556 /* Likewise, but for a different than the current function. */
557 extern HOST_WIDE_INT get_func_frame_size PARAMS ((struct function *));
559 /* These variables hold pointers to functions to create and destroy
560 target specific, per-function data structures. */
561 extern void (*init_machine_status) PARAMS ((struct function *));
562 extern void (*free_machine_status) PARAMS ((struct function *));
563 /* This variable holds a pointer to a function to register any
564 data items in the target specific, per-function data structure
565 that will need garbage collection. */
566 extern void (*mark_machine_status) PARAMS ((struct function *));
568 /* Likewise, but for language-specific data. */
569 extern void (*init_lang_status) PARAMS ((struct function *));
570 extern void (*mark_lang_status) PARAMS ((struct function *));
571 extern void (*save_lang_status) PARAMS ((struct function *));
572 extern void (*restore_lang_status) PARAMS ((struct function *));
573 extern void (*free_lang_status) PARAMS ((struct function *));
575 /* Save and restore status information for a nested function. */
576 extern void restore_emit_status PARAMS ((struct function *));
577 extern void free_after_parsing PARAMS ((struct function *));
578 extern void free_after_compilation PARAMS ((struct function *));
580 extern void init_varasm_status PARAMS ((struct function *));
581 extern void free_varasm_status PARAMS ((struct function *));
582 extern void free_emit_status PARAMS ((struct function *));
583 extern void free_stmt_status PARAMS ((struct function *));
584 extern void free_eh_status PARAMS ((struct function *));
585 extern void free_expr_status PARAMS ((struct function *));
587 extern rtx get_first_block_beg PARAMS ((void));
589 #ifdef RTX_CODE
590 extern void diddle_return_value PARAMS ((void (*)(rtx, void*), void*));
591 extern void clobber_return_register PARAMS ((void));
592 extern void use_return_register PARAMS ((void));
593 #endif
595 extern void init_virtual_regs PARAMS ((struct emit_status *));
597 /* Called once, at initialization, to initialize function.c. */
598 extern void init_function_once PARAMS ((void));
600 #ifdef rtx
601 #undef rtx
602 #endif
604 #ifdef tree
605 #undef tree
606 #endif