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, 2005, 2006, 2007, 2008
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
29 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
30 Each element describes one pending sequence.
31 The main insn-chain is saved in the last element of the chain,
32 unless the chain is empty. */
34 struct sequence_stack GTY(())
36 /* First and last insns in the chain of the saved sequence. */
39 struct sequence_stack *next;
42 struct emit_status GTY(())
44 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
45 After rtl generation, it is 1 plus the largest register number used. */
48 /* Lowest label number in current function. */
49 int x_first_label_num;
51 /* The ends of the doubly-linked chain of rtl for the current function.
52 Both are reset to null at the start of rtl generation for the function.
54 start_sequence saves both of these on `sequence_stack' and then starts
55 a new, nested sequence of insns. */
59 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
60 Each element describes one pending sequence.
61 The main insn-chain is saved in the last element of the chain,
62 unless the chain is empty. */
63 struct sequence_stack *sequence_stack;
65 /* INSN_UID for next insn emitted.
66 Reset to 1 for each function compiled. */
69 /* Location the last line-number NOTE emitted.
70 This is used to avoid generating duplicates. */
71 location_t x_last_location;
73 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
74 vectors. Since these vectors are needed during the expansion phase when
75 the total number of registers in the function is not yet known, the
76 vectors are copied and made bigger when necessary. */
77 int regno_pointer_align_length;
79 /* Indexed by pseudo register number, if nonzero gives the known alignment
80 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
81 Allocated in parallel with x_regno_reg_rtx. */
82 unsigned char * GTY((skip)) regno_pointer_align;
86 /* Indexed by pseudo register number, gives the rtx for that pseudo.
87 Allocated in parallel with regno_pointer_align.
88 FIXME: We could put it into emit_status struct, but gengtype is not able to deal
89 with length attribute nested in top level structures. */
91 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx * regno_reg_rtx;
93 /* For backward compatibility... eventually these should all go away. */
94 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
95 #define seq_stack (crtl->emit.sequence_stack)
97 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
99 struct expr_status GTY(())
101 /* Number of units that we should eventually pop off the stack.
102 These are the arguments to function calls that have already returned. */
103 int x_pending_stack_adjust;
105 /* Under some ABIs, it is the caller's responsibility to pop arguments
106 pushed for function calls. A naive implementation would simply pop
107 the arguments immediately after each call. However, if several
108 function calls are made in a row, it is typically cheaper to pop
109 all the arguments after all of the calls are complete since a
110 single pop instruction can be used. Therefore, GCC attempts to
111 defer popping the arguments until absolutely necessary. (For
112 example, at the end of a conditional, the arguments must be popped,
113 since code outside the conditional won't know whether or not the
114 arguments need to be popped.)
116 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
117 attempt to defer pops. Instead, the stack is popped immediately
118 after each call. Rather then setting this variable directly, use
119 NO_DEFER_POP and OK_DEFER_POP. */
120 int x_inhibit_defer_pop;
122 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
123 boundary can be momentarily unaligned while pushing the arguments.
124 Record the delta since last aligned boundary here in order to get
125 stack alignment in the nested function calls working right. */
126 int x_stack_pointer_delta;
128 /* Nonzero means __builtin_saveregs has already been done in this function.
129 The value is the pseudoreg containing the value __builtin_saveregs
131 rtx x_saveregs_value;
133 /* Similarly for __builtin_apply_args. */
134 rtx x_apply_args_value;
136 /* List of labels that must never be deleted. */
140 typedef struct call_site_record *call_site_record;
141 DEF_VEC_P(call_site_record);
142 DEF_VEC_ALLOC_P(call_site_record, gc);
144 /* RTL representation of exception handling. */
145 struct rtl_eh GTY(())
150 int built_landing_pads;
159 htab_t GTY ((param_is (struct ehl_map_entry))) exception_handler_label_map;
161 VEC(tree,gc) *ttype_data;
162 varray_type ehspec_data;
163 varray_type action_record_data;
165 VEC(call_site_record,gc) *call_site_record;
168 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
169 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
170 #define saveregs_value (crtl->expr.x_saveregs_value)
171 #define apply_args_value (crtl->expr.x_apply_args_value)
172 #define forced_labels (crtl->expr.x_forced_labels)
173 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
177 typedef struct temp_slot *temp_slot_p;
178 struct call_site_record;
180 DEF_VEC_P(temp_slot_p);
181 DEF_VEC_ALLOC_P(temp_slot_p,gc);
183 enum function_frequency {
184 /* This function most likely won't be executed at all.
185 (set only when profile feedback is available or via function attribute). */
186 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
187 /* The default value. */
188 FUNCTION_FREQUENCY_NORMAL,
189 /* Optimize this function hard
190 (set only when profile feedback is available or via function attribute). */
191 FUNCTION_FREQUENCY_HOT
194 struct varasm_status GTY(())
196 /* If we're using a per-function constant pool, this is it. */
197 struct rtx_constant_pool *pool;
199 /* Number of tree-constants deferred during the expansion of this
201 unsigned int deferred_constants;
204 /* Information mainlined about RTL representation of incoming arguments. */
205 struct incoming_args GTY(())
207 /* Number of bytes of args popped by function being compiled on its return.
208 Zero if no bytes are to be popped.
209 May affect compilation of return insn or of function epilogue. */
212 /* If function's args have a fixed size, this is that size, in bytes.
214 May affect compilation of return insn or of function epilogue. */
217 /* # bytes the prologue should push and pretend that the caller pushed them.
218 The prologue must do this, but only if parms can be passed in
220 int pretend_args_size;
222 /* This is the offset from the arg pointer to the place where the first
223 anonymous arg can be found, if there is one. */
226 /* Quantities of various kinds of registers
227 used for the current function's args. */
228 CUMULATIVE_ARGS info;
230 /* The arg pointer hard register, or the pseudo into which it was copied. */
231 rtx internal_arg_pointer;
234 /* Data for function partitioning. */
235 struct function_subsections GTY(())
237 /* Assembly labels for the hot and cold text sections, to
238 be used by debugger functions for determining the size of text
241 const char *hot_section_label;
242 const char *cold_section_label;
243 const char *hot_section_end_label;
244 const char *cold_section_end_label;
246 /* String to be used for name of cold text sections, via
247 targetm.asm_out.named_section. */
249 const char *unlikely_text_section_name;
252 /* Datastructures maintained for currently processed function in RTL form. */
253 struct rtl_data GTY(())
255 struct expr_status expr;
256 struct emit_status emit;
257 struct varasm_status varasm;
258 struct incoming_args args;
259 struct function_subsections subsections;
264 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
265 defined, the needed space is pushed by the prologue. */
266 int outgoing_args_size;
268 /* If nonzero, an RTL expression for the location at which the current
269 function returns its result. If the current function returns its
270 result in a register, current_function_return_rtx will always be
271 the hard register containing the result. */
274 /* Opaque pointer used by get_hard_reg_initial_val and
275 has_hard_reg_initial_val (see integrate.[hc]). */
276 struct initial_value_struct *hard_reg_initial_vals;
278 /* List (chain of EXPR_LIST) of labels heading the current handlers for
280 rtx x_nonlocal_goto_handler_labels;
282 /* Label that will go on function epilogue.
283 Jumping to this label serves as a "return" instruction
284 on machines which require execution of the epilogue on all returns. */
287 /* Label that will go on the end of function epilogue.
288 Jumping to this label serves as a "naked return" instruction
289 on machines which require execution of the epilogue on all returns. */
290 rtx x_naked_return_label;
292 /* List (chain of EXPR_LISTs) of all stack slots in this function.
293 Made for the sake of unshare_all_crtl-> */
294 rtx x_stack_slot_list;
296 /* Place after which to insert the tail_recursion_label if we need one. */
297 rtx x_stack_check_probe_note;
299 /* Location at which to save the argument pointer if it will need to be
300 referenced. There are two cases where this is done: if nonlocal gotos
301 exist, or if vars stored at an offset from the argument pointer will be
302 needed by inner routines. */
303 rtx x_arg_pointer_save_area;
305 /* Offset to end of allocated area of stack frame.
306 If stack grows down, this is the address of the last stack slot allocated.
307 If stack grows up, this is the address for the next slot. */
308 HOST_WIDE_INT x_frame_offset;
310 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
311 rtx x_parm_birth_insn;
313 /* List of all used temporaries allocated, by level. */
314 VEC(temp_slot_p,gc) *x_used_temp_slots;
316 /* List of available temp slots. */
317 struct temp_slot *x_avail_temp_slots;
319 /* Current nesting level for temporaries. */
320 int x_temp_slot_level;
324 #define return_label (crtl->x_return_label)
325 #define naked_return_label (crtl->x_naked_return_label)
326 #define stack_slot_list (crtl->x_stack_slot_list)
327 #define parm_birth_insn (crtl->x_parm_birth_insn)
328 #define frame_offset (crtl->x_frame_offset)
329 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
330 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
331 #define used_temp_slots (crtl->x_used_temp_slots)
332 #define avail_temp_slots (crtl->x_avail_temp_slots)
333 #define temp_slot_level (crtl->x_temp_slot_level)
334 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
336 extern GTY(()) struct rtl_data x_rtl;
338 /* Accestor to RTL datastructures. We keep them statically allocated now since
339 we never keep multiple functions. For threaded compiler we might however
340 want to do differntly. */
341 #define crtl (&x_rtl)
343 /* This structure can save all the important global and static variables
344 describing the status of the current function. */
346 struct function GTY(())
348 struct eh_status *eh;
350 /* The control flow graph for this function. */
351 struct control_flow_graph *cfg;
352 /* SSA and dataflow information. */
353 struct gimple_df *gimple_df;
355 /* The loops in this function. */
356 struct loops *x_current_loops;
358 /* Value histograms attached to particular statements. */
359 htab_t GTY((skip)) value_histograms;
361 /* For function.c. */
363 /* Points to the FUNCTION_DECL of this function. */
366 /* Function containing this function, if any. */
367 struct function *outer;
369 /* A PARM_DECL that should contain the static chain for this function.
370 It will be initialized at the beginning of the function. */
371 tree static_chain_decl;
373 /* An expression that contains the non-local goto save area. The first
374 word is the saved frame pointer and the second is the saved stack
376 tree nonlocal_goto_save_area;
378 /* Function sequence number for profiling, debugging, etc. */
383 /* tm.h can use this to store whatever it likes. */
384 struct machine_function * GTY ((maybe_undef)) machine;
386 /* The largest alignment of slot allocated on the stack. */
387 unsigned int stack_alignment_needed;
389 /* Preferred alignment of the end of stack frame. */
390 unsigned int preferred_stack_boundary;
392 /* Language-specific code can use this to store whatever it likes. */
393 struct language_function * language;
395 /* Used types hash table. */
396 htab_t GTY ((param_is (union tree_node))) used_types_hash;
400 /* If some insns can be deferred to the delay slots of the epilogue, the
401 delay list for them is recorded here. */
402 rtx epilogue_delay_list;
404 /* Maximal number of entities in the single jumptable. Used to estimate
405 final flowgraph size. */
406 int max_jumptable_ents;
408 /* UIDs for LABEL_DECLs. */
411 /* Line number of the end of the function. */
412 location_t function_end_locus;
414 /* The variables unexpanded so far. */
415 tree unexpanded_var_list;
417 /* A variable living at the top of the frame that holds a known value.
418 Used for detecting stack clobbers. */
419 tree stack_protect_guard;
421 /* Properties used by the pass manager. */
422 unsigned int curr_properties;
423 unsigned int last_verified;
425 /* Collected bit flags. */
427 /* Number of units of general registers that need saving in stdarg
428 function. What unit is depends on the backend, either it is number
429 of bytes, or it can be number of registers. */
430 unsigned int va_list_gpr_size : 8;
432 /* Number of units of floating point registers that need saving in stdarg
434 unsigned int va_list_fpr_size : 8;
437 /* How commonly executed the function is. Initialized during branch
438 probabilities pass. */
439 ENUM_BITFIELD (function_frequency) function_frequency : 2;
441 /* Nonzero if function being compiled can call setjmp. */
442 unsigned int calls_setjmp : 1;
444 /* Nonzero if function being compiled can call alloca,
445 either as a subroutine or builtin. */
446 unsigned int calls_alloca : 1;
448 /* Nonzero if function being compiled called builtin_return_addr or
449 builtin_frame_address with nonzero count. */
450 unsigned int accesses_prior_frames : 1;
452 /* Nonzero if the function calls __builtin_eh_return. */
453 unsigned int calls_eh_return : 1;
456 /* Nonzero if function being compiled receives nonlocal gotos
457 from nested functions. */
458 unsigned int has_nonlocal_label : 1;
460 /* Nonzero if function saves all registers, e.g. if it has a nonlocal
461 label that can reach the exit block via non-exceptional paths. */
462 unsigned int saves_all_registers : 1;
464 /* Nonzero if function being compiled has nonlocal gotos to parent
466 unsigned int has_nonlocal_goto : 1;
468 /* Nonzero if function being compiled has an asm statement. */
469 unsigned int has_asm_statement : 1;
471 /* Nonzero if the current function is a thunk, i.e., a lightweight
472 function implemented by the output_mi_thunk hook) that just
473 adjusts one of its arguments and forwards to another
475 unsigned int is_thunk : 1;
477 /* This bit is used by the exception handling logic. It is set if all
478 calls (if any) are sibling calls. Such functions do not have to
479 have EH tables generated, as they cannot throw. A call to such a
480 function, however, should be treated as throwing if any of its callees
482 unsigned int all_throwers_are_sibcalls : 1;
484 /* Nonzero if profiling code should be generated. */
485 unsigned int profile : 1;
487 /* Nonzero if stack limit checking should be enabled in the current
489 unsigned int limit_stack : 1;
492 /* Nonzero if current function uses stdarg.h or equivalent. */
493 unsigned int stdarg : 1;
495 /* Nonzero if the back-end should not keep track of expressions that
496 determine the size of variable-sized objects. Normally, such
497 expressions are saved away, and then expanded when the next
498 function is started. For example, if a parameter has a
499 variable-sized type, then the size of the parameter is computed
500 when the function body is entered. However, some front-ends do
501 not desire this behavior. */
502 unsigned int x_dont_save_pending_sizes_p : 1;
504 /* Nonzero if the current function uses the constant pool. */
505 unsigned int uses_const_pool : 1;
507 /* Nonzero if the current function uses pic_offset_table_rtx. */
508 unsigned int uses_pic_offset_table : 1;
510 /* Nonzero if the current function needs an lsda for exception handling. */
511 unsigned int uses_eh_lsda : 1;
513 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
514 unsigned int arg_pointer_save_area_init : 1;
516 unsigned int after_inlining : 1;
518 /* Set when the call to function itself has been emit. */
519 unsigned int recursive_call_emit : 1;
522 /* Set when the tail call has been produced. */
523 unsigned int tail_call_emit : 1;
525 /* FIXME tuples: This bit is temporarily here to mark when a
526 function has been gimplified, so we can make sure we're not
527 creating non GIMPLE tuples after gimplification. */
528 unsigned int gimplified : 1;
530 /* Fields below this point are not set for abstract functions; see
531 allocate_struct_function. */
533 /* Nonzero if function being compiled needs to be given an address
534 where the value should be stored. */
535 unsigned int returns_struct : 1;
537 /* Nonzero if function being compiled needs to
538 return the address of where it has put a structure value. */
539 unsigned int returns_pcc_struct : 1;
541 /* Nonzero if pass_tree_profile was run on this function. */
542 unsigned int after_tree_profile : 1;
545 /* If va_list_[gf]pr_size is set to this, it means we don't know how
546 many units need to be saved. */
547 #define VA_LIST_MAX_GPR_SIZE 255
548 #define VA_LIST_MAX_FPR_SIZE 255
550 /* The function currently being compiled. */
551 extern GTY(()) struct function *cfun;
553 /* In order to ensure that cfun is not set directly, we redefine it so
554 that it is not an lvalue. Rather than assign to cfun, use
555 push_cfun or set_cfun. */
556 #define cfun (cfun + 0)
558 /* Pointer to chain of `struct function' for containing functions. */
559 extern GTY(()) struct function *outer_function_chain;
561 /* Nonzero if we've already converted virtual regs to hard regs. */
562 extern int virtuals_instantiated;
564 /* Nonzero if at least one trampoline has been created. */
565 extern int trampolines_created;
567 /* cfun shouldn't be set directly; use one of these functions instead. */
568 extern void set_cfun (struct function *new_cfun);
569 extern void push_cfun (struct function *new_cfun);
570 extern void pop_cfun (void);
571 extern void instantiate_decl_rtl (rtx x);
573 /* For backward compatibility... eventually these should all go away. */
574 #define current_function_returns_struct (cfun->returns_struct)
575 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
576 #define current_function_calls_setjmp (cfun->calls_setjmp)
577 #define current_function_calls_alloca (cfun->calls_alloca)
578 #define current_function_accesses_prior_frames (cfun->accesses_prior_frames)
579 #define current_function_calls_eh_return (cfun->calls_eh_return)
580 #define current_function_is_thunk (cfun->is_thunk)
581 #define current_function_stdarg (cfun->stdarg)
582 #define current_function_profile (cfun->profile)
583 #define current_function_funcdef_no (cfun->funcdef_no)
584 #define current_function_limit_stack (cfun->limit_stack)
585 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
586 #define current_function_uses_const_pool (cfun->uses_const_pool)
587 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
588 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
589 #define current_function_saves_all_registers (cfun->saves_all_registers)
590 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
591 #define current_function_has_asm_statement (cfun->has_asm_statement)
593 #define current_loops (cfun->x_current_loops)
594 #define dom_computed (cfun->cfg->x_dom_computed)
595 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
596 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
598 /* Given a function decl for a containing function,
599 return the `struct function' for it. */
600 struct function *find_function_data (tree);
602 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
603 and create duplicate blocks. */
604 extern void reorder_blocks (void);
606 /* Set BLOCK_NUMBER for all the blocks in FN. */
607 extern void number_blocks (tree);
609 extern void clear_block_marks (tree);
610 extern tree blocks_nreverse (tree);
612 /* Return size needed for stack frame based on slots so far allocated.
613 This size counts from zero. It is not rounded to STACK_BOUNDARY;
614 the caller may have to do that. */
615 extern HOST_WIDE_INT get_frame_size (void);
617 /* Issue an error message and return TRUE if frame OFFSET overflows in
618 the signed target pointer arithmetics for function FUNC. Otherwise
620 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
622 /* A pointer to a function to create target specific, per-function
624 extern struct machine_function * (*init_machine_status) (void);
626 /* Save and restore status information for a nested function. */
627 extern void free_after_parsing (struct function *);
628 extern void free_after_compilation (struct function *);
630 extern void init_varasm_status (void);
633 extern void diddle_return_value (void (*)(rtx, void*), void*);
634 extern void clobber_return_register (void);
637 extern rtx get_arg_pointer_save_area (void);
639 /* Returns the name of the current function. */
640 extern const char *current_function_name (void);
641 /* Returns the assembler name (raw, mangled) of the current function. */
642 extern const char *current_function_assembler_name (void);
644 extern void do_warn_unused_parameter (tree);
646 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
648 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
651 extern void used_types_insert (tree);
653 extern int get_next_funcdef_no (void);
654 #endif /* GCC_FUNCTION_H */