1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2003, 2004 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
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
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
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
25 struct var_refs_queue GTY(())
28 enum machine_mode promoted_mode;
30 struct var_refs_queue *next;
33 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
34 Each element describes one pending sequence.
35 The main insn-chain is saved in the last element of the chain,
36 unless the chain is empty. */
38 struct sequence_stack GTY(())
40 /* First and last insns in the chain of the saved sequence. */
43 struct sequence_stack *next;
46 extern struct sequence_stack *sequence_stack;
48 /* Stack of single obstacks. */
50 struct simple_obstack_stack
52 struct obstack *obstack;
53 struct simple_obstack_stack *next;
56 struct emit_status GTY(())
58 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
59 After rtl generation, it is 1 plus the largest register number used. */
62 /* Lowest label number in current function. */
63 int x_first_label_num;
65 /* The ends of the doubly-linked chain of rtl for the current function.
66 Both are reset to null at the start of rtl generation for the function.
68 start_sequence saves both of these on `sequence_stack' and then starts
69 a new, nested sequence of insns. */
73 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
74 Each element describes one pending sequence.
75 The main insn-chain is saved in the last element of the chain,
76 unless the chain is empty. */
77 struct sequence_stack *sequence_stack;
79 /* INSN_UID for next insn emitted.
80 Reset to 1 for each function compiled. */
83 /* Location the last line-number NOTE emitted.
84 This is used to avoid generating duplicates. */
85 location_t x_last_location;
87 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
88 vectors. Since these vectors are needed during the expansion phase when
89 the total number of registers in the function is not yet known, the
90 vectors are copied and made bigger when necessary. */
91 int regno_pointer_align_length;
93 /* Indexed by pseudo register number, if nonzero gives the known alignment
94 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
95 Allocated in parallel with x_regno_reg_rtx. */
96 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
99 /* Indexed by pseudo register number, gives the rtx for that pseudo.
100 Allocated in parallel with regno_pointer_align.
102 Note MEM expressions can appear in this array due to the actions
103 of put_var_into_stack. */
104 rtx * GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx;
107 /* For backward compatibility... eventually these should all go away. */
108 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
109 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
110 #define seq_stack (cfun->emit->sequence_stack)
112 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
114 struct expr_status GTY(())
116 /* Number of units that we should eventually pop off the stack.
117 These are the arguments to function calls that have already returned. */
118 int x_pending_stack_adjust;
120 /* Under some ABIs, it is the caller's responsibility to pop arguments
121 pushed for function calls. A naive implementation would simply pop
122 the arguments immediately after each call. However, if several
123 function calls are made in a row, it is typically cheaper to pop
124 all the arguments after all of the calls are complete since a
125 single pop instruction can be used. Therefore, GCC attempts to
126 defer popping the arguments until absolutely necessary. (For
127 example, at the end of a conditional, the arguments must be popped,
128 since code outside the conditional won't know whether or not the
129 arguments need to be popped.)
131 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
132 attempt to defer pops. Instead, the stack is popped immediately
133 after each call. Rather then setting this variable directly, use
134 NO_DEFER_POP and OK_DEFER_POP. */
135 int x_inhibit_defer_pop;
137 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
138 boundary can be momentarily unaligned while pushing the arguments.
139 Record the delta since last aligned boundary here in order to get
140 stack alignment in the nested function calls working right. */
141 int x_stack_pointer_delta;
143 /* Nonzero means __builtin_saveregs has already been done in this function.
144 The value is the pseudoreg containing the value __builtin_saveregs
146 rtx x_saveregs_value;
148 /* Similarly for __builtin_apply_args. */
149 rtx x_apply_args_value;
151 /* List of labels that must never be deleted. */
154 /* Postincrements that still need to be expanded. */
158 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
159 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
160 #define saveregs_value (cfun->expr->x_saveregs_value)
161 #define apply_args_value (cfun->expr->x_apply_args_value)
162 #define forced_labels (cfun->expr->x_forced_labels)
163 #define pending_chain (cfun->expr->x_pending_chain)
164 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
166 /* This structure can save all the important global and static variables
167 describing the status of the current function. */
169 struct function GTY(())
171 struct eh_status *eh;
172 struct stmt_status *stmt;
173 struct expr_status *expr;
174 struct emit_status *emit;
175 struct varasm_status *varasm;
177 /* For tree-optimize.c. */
179 /* Saved tree and arguments during tree optimization. Used later for
184 /* For function.c. */
186 /* Points to the FUNCTION_DECL of this function. */
189 /* Function containing this function, if any. */
190 struct function *outer;
192 /* Number of bytes of args popped by function being compiled on its return.
193 Zero if no bytes are to be popped.
194 May affect compilation of return insn or of function epilogue. */
197 /* If function's args have a fixed size, this is that size, in bytes.
199 May affect compilation of return insn or of function epilogue. */
202 /* # bytes the prologue should push and pretend that the caller pushed them.
203 The prologue must do this, but only if parms can be passed in
205 int pretend_args_size;
207 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
208 defined, the needed space is pushed by the prologue. */
209 int outgoing_args_size;
211 /* This is the offset from the arg pointer to the place where the first
212 anonymous arg can be found, if there is one. */
215 /* Quantities of various kinds of registers
216 used for the current function's args. */
217 CUMULATIVE_ARGS args_info;
219 /* If nonzero, an RTL expression for the location at which the current
220 function returns its result. If the current function returns its
221 result in a register, current_function_return_rtx will always be
222 the hard register containing the result. */
225 /* The arg pointer hard register, or the pseudo into which it was copied. */
226 rtx internal_arg_pointer;
228 /* Opaque pointer used by get_hard_reg_initial_val and
229 has_hard_reg_initial_val (see integrate.[hc]). */
230 struct initial_value_struct *hard_reg_initial_vals;
232 /* List (chain of EXPR_LIST) of labels heading the current handlers for
234 rtx x_nonlocal_goto_handler_labels;
236 /* Label that will go on function epilogue.
237 Jumping to this label serves as a "return" instruction
238 on machines which require execution of the epilogue on all returns. */
241 /* Label that will go on the end of function epilogue.
242 Jumping to this label serves as a "naked return" instruction
243 on machines which require execution of the epilogue on all returns. */
244 rtx x_naked_return_label;
246 /* List (chain of EXPR_LISTs) of all stack slots in this function.
247 Made for the sake of unshare_all_rtl. */
248 rtx x_stack_slot_list;
250 /* Place after which to insert the tail_recursion_label if we need one. */
251 rtx x_tail_recursion_reentry;
253 /* Location at which to save the argument pointer if it will need to be
254 referenced. There are two cases where this is done: if nonlocal gotos
255 exist, or if vars stored at an offset from the argument pointer will be
256 needed by inner routines. */
257 rtx x_arg_pointer_save_area;
259 /* Offset to end of allocated area of stack frame.
260 If stack grows down, this is the address of the last stack slot allocated.
261 If stack grows up, this is the address for the next slot. */
262 HOST_WIDE_INT x_frame_offset;
264 /* A VAR_DECL that should contain the static chain for this function.
265 It will be initialized at the beginning of the function. */
266 tree static_chain_decl;
268 /* An expression that contains the non-local goto save area. The first
269 word is the saved frame pointer and the second is the saved stack
271 tree nonlocal_goto_save_area;
273 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
274 rtx x_parm_birth_insn;
276 /* 1 + last pseudo register number possibly used for loading a copy
277 of a parameter of this function. */
278 unsigned int x_max_parm_reg;
280 /* Vector indexed by REGNO, containing location on stack in which
281 to put the parm which is nominally in pseudo register REGNO,
282 if we discover that that parm must go in the stack. The highest
283 element in this vector is one less than MAX_PARM_REG, above. */
284 rtx * GTY ((length ("%h.x_max_parm_reg"))) x_parm_reg_stack_loc;
286 /* List of all used temporaries allocated, by level. */
287 struct varray_head_tag * GTY((param_is (struct temp_slot))) x_used_temp_slots;
289 /* List of available temp slots. */
290 struct temp_slot *x_avail_temp_slots;
292 /* Current nesting level for temporaries. */
293 int x_temp_slot_level;
295 /* Current nesting level for variables in a block. */
296 int x_var_temp_slot_level;
298 /* When temporaries are created by TARGET_EXPRs, they are created at
299 this level of temp_slot_level, so that they can remain allocated
300 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
302 int x_target_temp_slot_level;
304 /* This slot is initialized as 0 and is added to
305 during the nested function. */
306 struct var_refs_queue *fixup_var_refs_queue;
308 /* For integrate.c. */
310 int no_debugging_symbols;
311 rtvec original_arg_vector;
312 tree original_decl_initial;
313 /* Highest label number in current function. */
314 int inl_max_label_num;
316 /* Function sequence number for profiling, debugging, etc. */
321 /* tm.h can use this to store whatever it likes. */
322 struct machine_function * GTY ((maybe_undef)) machine;
323 /* The largest alignment of slot allocated on the stack. */
324 int stack_alignment_needed;
325 /* Preferred alignment of the end of stack frame. */
326 int preferred_stack_boundary;
327 /* Set when the call to function itself has been emit. */
328 bool recursive_call_emit;
329 /* Set when the tail call has been produced. */
332 /* Language-specific code can use this to store whatever it likes. */
333 struct language_function * language;
337 /* If some insns can be deferred to the delay slots of the epilogue, the
338 delay list for them is recorded here. */
339 rtx epilogue_delay_list;
341 /* How commonly executed the function is. Initialized during branch
342 probabilities pass. */
343 enum function_frequency {
344 /* This function most likely won't be executed at all.
345 (set only when profile feedback is available). */
346 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
347 /* The default value. */
348 FUNCTION_FREQUENCY_NORMAL,
349 /* Optimize this function hard
350 (set only when profile feedback is available). */
351 FUNCTION_FREQUENCY_HOT
352 } function_frequency;
354 /* Maximal number of entities in the single jumptable. Used to estimate
355 final flowgraph size. */
356 int max_jumptable_ents;
358 /* UIDs for LABEL_DECLs. */
361 /* Line number of the end of the function. */
362 location_t function_end_locus;
364 /* Array mapping insn uids to blocks. */
365 struct varray_head_tag *ib_boundaries_block;
367 /* The variables unexpanded so far. */
368 tree unexpanded_var_list;
370 /* Collected bit flags. */
372 /* Nonzero if function being compiled needs to be given an address
373 where the value should be stored. */
374 unsigned int returns_struct : 1;
376 /* Nonzero if function being compiled needs to
377 return the address of where it has put a structure value. */
378 unsigned int returns_pcc_struct : 1;
380 /* Nonzero if the current function returns a pointer type. */
381 unsigned int returns_pointer : 1;
383 /* Nonzero if function being compiled can call setjmp. */
384 unsigned int calls_setjmp : 1;
386 /* Nonzero if function being compiled can call longjmp. */
387 unsigned int calls_longjmp : 1;
389 /* Nonzero if function being compiled can call alloca,
390 either as a subroutine or builtin. */
391 unsigned int calls_alloca : 1;
393 /* Nonzero if the function calls __builtin_eh_return. */
394 unsigned int calls_eh_return : 1;
396 /* Nonzero if function being compiled receives nonlocal gotos
397 from nested functions. */
398 unsigned int has_nonlocal_label : 1;
400 /* Nonzero if function being compiled has nonlocal gotos to parent
402 unsigned int has_nonlocal_goto : 1;
404 /* Nonzero if function being compiled contains nested functions. */
405 unsigned int contains_functions : 1;
407 /* Nonzero if the function being compiled issues a computed jump. */
408 unsigned int has_computed_jump : 1;
410 /* Nonzero if the current function is a thunk, i.e., a lightweight
411 function implemented by the output_mi_thunk hook) that just
412 adjusts one of its arguments and forwards to another
414 unsigned int is_thunk : 1;
416 /* This bit is used by the exception handling logic. It is set if all
417 calls (if any) are sibling calls. Such functions do not have to
418 have EH tables generated, as they cannot throw. A call to such a
419 function, however, should be treated as throwing if any of its callees
421 unsigned int all_throwers_are_sibcalls : 1;
423 /* Nonzero if instrumentation calls for function entry and exit should be
425 unsigned int instrument_entry_exit : 1;
427 /* Nonzero if profiling code should be generated. */
428 unsigned int profile : 1;
430 /* Nonzero if stack limit checking should be enabled in the current
432 unsigned int limit_stack : 1;
434 /* Nonzero if current function uses stdarg.h or equivalent. */
435 unsigned int stdarg : 1;
437 /* Nonzero if the back-end should not keep track of expressions that
438 determine the size of variable-sized objects. Normally, such
439 expressions are saved away, and then expanded when the next
440 function is started. For example, if a parameter has a
441 variable-sized type, then the size of the parameter is computed
442 when the function body is entered. However, some front-ends do
443 not desire this behavior. */
444 unsigned int x_dont_save_pending_sizes_p : 1;
446 /* Nonzero if the current function uses the constant pool. */
447 unsigned int uses_const_pool : 1;
449 /* Nonzero if the current function uses pic_offset_table_rtx. */
450 unsigned int uses_pic_offset_table : 1;
452 /* Nonzero if the current function needs an lsda for exception handling. */
453 unsigned int uses_eh_lsda : 1;
455 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
456 unsigned int arg_pointer_save_area_init : 1;
459 /* The function currently being compiled. */
460 extern GTY(()) struct function *cfun;
462 /* Pointer to chain of `struct function' for containing functions. */
463 extern GTY(()) struct function *outer_function_chain;
465 /* Nonzero if we've already converted virtual regs to hard regs. */
466 extern int virtuals_instantiated;
468 /* Nonzero if at least one trampoline has been created. */
469 extern int trampolines_created;
471 /* For backward compatibility... eventually these should all go away. */
472 #define current_function_pops_args (cfun->pops_args)
473 #define current_function_returns_struct (cfun->returns_struct)
474 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
475 #define current_function_returns_pointer (cfun->returns_pointer)
476 #define current_function_calls_setjmp (cfun->calls_setjmp)
477 #define current_function_calls_alloca (cfun->calls_alloca)
478 #define current_function_calls_longjmp (cfun->calls_longjmp)
479 #define current_function_calls_eh_return (cfun->calls_eh_return)
480 #define current_function_has_computed_jump (cfun->has_computed_jump)
481 #define current_function_contains_functions (cfun->contains_functions)
482 #define current_function_is_thunk (cfun->is_thunk)
483 #define current_function_args_info (cfun->args_info)
484 #define current_function_args_size (cfun->args_size)
485 #define current_function_pretend_args_size (cfun->pretend_args_size)
486 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
487 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
488 #define current_function_stdarg (cfun->stdarg)
489 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
490 #define current_function_return_rtx (cfun->return_rtx)
491 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
492 #define current_function_profile (cfun->profile)
493 #define current_function_funcdef_no (cfun->funcdef_no)
494 #define current_function_limit_stack (cfun->limit_stack)
495 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
496 #define current_function_uses_const_pool (cfun->uses_const_pool)
497 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
498 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
499 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
501 #define max_parm_reg (cfun->x_max_parm_reg)
502 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
503 #define return_label (cfun->x_return_label)
504 #define naked_return_label (cfun->x_naked_return_label)
505 #define stack_slot_list (cfun->x_stack_slot_list)
506 #define parm_birth_insn (cfun->x_parm_birth_insn)
507 #define frame_offset (cfun->x_frame_offset)
508 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
509 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
510 #define used_temp_slots (cfun->x_used_temp_slots)
511 #define avail_temp_slots (cfun->x_avail_temp_slots)
512 #define temp_slot_level (cfun->x_temp_slot_level)
513 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
514 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
515 #define nonlocal_labels (cfun->x_nonlocal_labels)
516 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
518 /* Given a function decl for a containing function,
519 return the `struct function' for it. */
520 struct function *find_function_data (tree);
522 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
523 and create duplicate blocks. */
524 extern void reorder_blocks (void);
526 /* Set BLOCK_NUMBER for all the blocks in FN. */
527 extern void number_blocks (tree);
529 extern void clear_block_marks (tree);
530 extern tree blocks_nreverse (tree);
531 extern void reset_block_changes (void);
532 extern void record_block_change (tree);
533 extern void finalize_block_changes (void);
534 extern void check_block_change (rtx, tree *);
535 extern void free_block_changes (void);
537 /* Return size needed for stack frame based on slots so far allocated.
538 This size counts from zero. It is not rounded to STACK_BOUNDARY;
539 the caller may have to do that. */
540 extern HOST_WIDE_INT get_frame_size (void);
541 /* Likewise, but for a different than the current function. */
542 extern HOST_WIDE_INT get_func_frame_size (struct function *);
544 /* A pointer to a function to create target specific, per-function
546 extern struct machine_function * (*init_machine_status) (void);
548 /* Save and restore status information for a nested function. */
549 extern void restore_emit_status (struct function *);
550 extern void free_after_parsing (struct function *);
551 extern void free_after_compilation (struct function *);
553 extern void init_varasm_status (struct function *);
556 extern void diddle_return_value (void (*)(rtx, void*), void*);
557 extern void clobber_return_register (void);
558 extern void use_return_register (void);
561 extern rtx get_arg_pointer_save_area (struct function *);
563 extern void init_virtual_regs (struct emit_status *);
564 extern void instantiate_virtual_regs (void);
566 /* Returns the name of the current function. */
567 extern const char *current_function_name (void);
569 /* Called once, at initialization, to initialize function.c. */
570 extern void init_function_once (void);
572 extern void do_warn_unused_parameter (tree);
574 #endif /* GCC_FUNCTION_H */