1 /* Structure for saving state for a nested function.
2    Copyright (C) 1989-2013 Free Software Foundation, Inc.
3 
4 This file is part of GCC.
5 
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10 
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 for more details.
15 
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3.  If not see
18 <http://www.gnu.org/licenses/>.  */
19 
20 #ifndef GCC_FUNCTION_H
21 #define GCC_FUNCTION_H
22 
23 #include "hashtab.h"
24 #include "vec.h"
25 #include "machmode.h"
26 #include "tm.h"			/* For CUMULATIVE_ARGS.  */
27 #include "hard-reg-set.h"	/* For HARD_REG_SET in struct rtl_data. */
28 #include "input.h"		/* For location_t.  */
29 
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.  */
34 
35 struct GTY(()) sequence_stack {
36   /* First and last insns in the chain of the saved sequence.  */
37   rtx first;
38   rtx last;
39   struct sequence_stack *next;
40 };
41 
42 struct GTY(()) emit_status {
43   /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
44      After rtl generation, it is 1 plus the largest register number used.  */
45   int x_reg_rtx_no;
46 
47   /* Lowest label number in current function.  */
48   int x_first_label_num;
49 
50   /* The ends of the doubly-linked chain of rtl for the current function.
51      Both are reset to null at the start of rtl generation for the function.
52 
53      start_sequence saves both of these on `sequence_stack' and then starts
54      a new, nested sequence of insns.  */
55   rtx x_first_insn;
56   rtx x_last_insn;
57 
58   /* Stack of pending (incomplete) sequences saved by `start_sequence'.
59      Each element describes one pending sequence.
60      The main insn-chain is saved in the last element of the chain,
61      unless the chain is empty.  */
62   struct sequence_stack *sequence_stack;
63 
64   /* INSN_UID for next insn emitted.
65      Reset to 1 for each function compiled.  */
66   int x_cur_insn_uid;
67 
68   /* INSN_UID for next debug insn emitted.  Only used if
69      --param min-nondebug-insn-uid=<value> is given with nonzero value.  */
70   int x_cur_debug_insn_uid;
71 
72   /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
73      vectors.  Since these vectors are needed during the expansion phase when
74      the total number of registers in the function is not yet known, the
75      vectors are copied and made bigger when necessary.  */
76   int regno_pointer_align_length;
77 
78   /* Indexed by pseudo register number, if nonzero gives the known alignment
79      for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
80      Allocated in parallel with x_regno_reg_rtx.  */
81   unsigned char * GTY((skip)) regno_pointer_align;
82 };
83 
84 
85 /* Indexed by register number, gives an rtx for that register (and only
86    that register).  For pseudo registers, it is the unique rtx for
87    that pseudo.  For hard registers, it is an rtx of the mode specified
88    by reg_raw_mode.
89 
90    FIXME: We could put it into emit_status struct, but gengtype is not
91    able to deal with length attribute nested in top level structures.  */
92 
93 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx * regno_reg_rtx;
94 
95 /* For backward compatibility... eventually these should all go away.  */
96 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
97 #define seq_stack (crtl->emit.sequence_stack)
98 
99 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
100 
101 struct GTY(()) expr_status {
102   /* Number of units that we should eventually pop off the stack.
103      These are the arguments to function calls that have already returned.  */
104   int x_pending_stack_adjust;
105 
106   /* Under some ABIs, it is the caller's responsibility to pop arguments
107      pushed for function calls.  A naive implementation would simply pop
108      the arguments immediately after each call.  However, if several
109      function calls are made in a row, it is typically cheaper to pop
110      all the arguments after all of the calls are complete since a
111      single pop instruction can be used.  Therefore, GCC attempts to
112      defer popping the arguments until absolutely necessary.  (For
113      example, at the end of a conditional, the arguments must be popped,
114      since code outside the conditional won't know whether or not the
115      arguments need to be popped.)
116 
117      When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
118      attempt to defer pops.  Instead, the stack is popped immediately
119      after each call.  Rather then setting this variable directly, use
120      NO_DEFER_POP and OK_DEFER_POP.  */
121   int x_inhibit_defer_pop;
122 
123   /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
124      boundary can be momentarily unaligned while pushing the arguments.
125      Record the delta since last aligned boundary here in order to get
126      stack alignment in the nested function calls working right.  */
127   int x_stack_pointer_delta;
128 
129   /* Nonzero means __builtin_saveregs has already been done in this function.
130      The value is the pseudoreg containing the value __builtin_saveregs
131      returned.  */
132   rtx x_saveregs_value;
133 
134   /* Similarly for __builtin_apply_args.  */
135   rtx x_apply_args_value;
136 
137   /* List of labels that must never be deleted.  */
138   rtx x_forced_labels;
139 };
140 
141 typedef struct call_site_record_d *call_site_record;
142 
143 /* RTL representation of exception handling.  */
144 struct GTY(()) rtl_eh {
145   rtx ehr_stackadj;
146   rtx ehr_handler;
147   rtx ehr_label;
148 
149   rtx sjlj_fc;
150   rtx sjlj_exit_after;
151 
152   vec<uchar, va_gc> *action_record_data;
153 
154   vec<call_site_record, va_gc> *call_site_record_v[2];
155 };
156 
157 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
158 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
159 #define saveregs_value (crtl->expr.x_saveregs_value)
160 #define apply_args_value (crtl->expr.x_apply_args_value)
161 #define forced_labels (crtl->expr.x_forced_labels)
162 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
163 
164 struct gimple_df;
165 struct temp_slot;
166 typedef struct temp_slot *temp_slot_p;
167 struct call_site_record_d;
168 struct dw_fde_struct;
169 
170 struct ipa_opt_pass_d;
171 typedef struct ipa_opt_pass_d *ipa_opt_pass;
172 
173 
174 struct GTY(()) varasm_status {
175   /* If we're using a per-function constant pool, this is it.  */
176   struct rtx_constant_pool *pool;
177 
178   /* Number of tree-constants deferred during the expansion of this
179      function.  */
180   unsigned int deferred_constants;
181 };
182 
183 /* Information mainlined about RTL representation of incoming arguments.  */
184 struct GTY(()) incoming_args {
185   /* Number of bytes of args popped by function being compiled on its return.
186      Zero if no bytes are to be popped.
187      May affect compilation of return insn or of function epilogue.  */
188   int pops_args;
189 
190   /* If function's args have a fixed size, this is that size, in bytes.
191      Otherwise, it is -1.
192      May affect compilation of return insn or of function epilogue.  */
193   int size;
194 
195   /* # bytes the prologue should push and pretend that the caller pushed them.
196      The prologue must do this, but only if parms can be passed in
197      registers.  */
198   int pretend_args_size;
199 
200   /* This is the offset from the arg pointer to the place where the first
201      anonymous arg can be found, if there is one.  */
202   rtx arg_offset_rtx;
203 
204   /* Quantities of various kinds of registers
205      used for the current function's args.  */
206   CUMULATIVE_ARGS info;
207 
208   /* The arg pointer hard register, or the pseudo into which it was copied.  */
209   rtx internal_arg_pointer;
210 };
211 
212 /* Data for function partitioning.  */
213 struct GTY(()) function_subsections {
214   /* Assembly labels for the hot and cold text sections, to
215      be used by debugger functions for determining the size of text
216      sections.  */
217 
218   const char *hot_section_label;
219   const char *cold_section_label;
220   const char *hot_section_end_label;
221   const char *cold_section_end_label;
222 };
223 
224 /* Describe an empty area of space in the stack frame.  These can be chained
225    into a list; this is used to keep track of space wasted for alignment
226    reasons.  */
227 struct GTY(()) frame_space
228 {
229   struct frame_space *next;
230 
231   HOST_WIDE_INT start;
232   HOST_WIDE_INT length;
233 };
234 
235 /* Datastructures maintained for currently processed function in RTL form.  */
236 struct GTY(()) rtl_data {
237   struct expr_status expr;
238   struct emit_status emit;
239   struct varasm_status varasm;
240   struct incoming_args args;
241   struct function_subsections subsections;
242   struct rtl_eh eh;
243 
244   /* For function.c  */
245 
246   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
247      defined, the needed space is pushed by the prologue.  */
248   int outgoing_args_size;
249 
250   /* If nonzero, an RTL expression for the location at which the current
251      function returns its result.  If the current function returns its
252      result in a register, current_function_return_rtx will always be
253      the hard register containing the result.  */
254   rtx return_rtx;
255 
256   /* Vector of initial-value pairs.  Each pair consists of a pseudo
257      register of approprite mode that stores the initial value a hard
258      register REGNO, and that hard register itself.  */
259   /* ??? This could be a VEC but there is currently no way to define an
260 	 opaque VEC type.  */
261   struct initial_value_struct *hard_reg_initial_vals;
262 
263   /* A variable living at the top of the frame that holds a known value.
264      Used for detecting stack clobbers.  */
265   tree stack_protect_guard;
266 
267   /* List (chain of EXPR_LIST) of labels heading the current handlers for
268      nonlocal gotos.  */
269   rtx x_nonlocal_goto_handler_labels;
270 
271   /* Label that will go on function epilogue.
272      Jumping to this label serves as a "return" instruction
273      on machines which require execution of the epilogue on all returns.  */
274   rtx x_return_label;
275 
276   /* Label that will go on the end of function epilogue.
277      Jumping to this label serves as a "naked return" instruction
278      on machines which require execution of the epilogue on all returns.  */
279   rtx x_naked_return_label;
280 
281   /* List (chain of EXPR_LISTs) of all stack slots in this function.
282      Made for the sake of unshare_all_rtl.  */
283   rtx x_stack_slot_list;
284 
285   /* List of empty areas in the stack frame.  */
286   struct frame_space *frame_space_list;
287 
288   /* Place after which to insert the tail_recursion_label if we need one.  */
289   rtx x_stack_check_probe_note;
290 
291   /* Location at which to save the argument pointer if it will need to be
292      referenced.  There are two cases where this is done: if nonlocal gotos
293      exist, or if vars stored at an offset from the argument pointer will be
294      needed by inner routines.  */
295   rtx x_arg_pointer_save_area;
296 
297   /* Dynamic Realign Argument Pointer used for realigning stack.  */
298   rtx drap_reg;
299 
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;
304 
305   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
306   rtx x_parm_birth_insn;
307 
308   /* List of all used temporaries allocated, by level.  */
309   vec<temp_slot_p, va_gc> *x_used_temp_slots;
310 
311   /* List of available temp slots.  */
312   struct temp_slot *x_avail_temp_slots;
313 
314   /* Current nesting level for temporaries.  */
315   int x_temp_slot_level;
316 
317   /* The largest alignment needed on the stack, including requirement
318      for outgoing stack alignment.  */
319   unsigned int stack_alignment_needed;
320 
321   /* Preferred alignment of the end of stack frame, which is preferred
322      to call other functions.  */
323   unsigned int preferred_stack_boundary;
324 
325   /* The minimum alignment of parameter stack.  */
326   unsigned int parm_stack_boundary;
327 
328   /* The largest alignment of slot allocated on the stack.  */
329   unsigned int max_used_stack_slot_alignment;
330 
331   /* The stack alignment estimated before reload, with consideration of
332      following factors:
333      1. Alignment of local stack variables (max_used_stack_slot_alignment)
334      2. Alignment requirement to call other functions
335         (preferred_stack_boundary)
336      3. Alignment of non-local stack variables but might be spilled in
337         local stack.  */
338   unsigned int stack_alignment_estimated;
339 
340   /* For reorg.  */
341 
342   /* Nonzero if function being compiled called builtin_return_addr or
343      builtin_frame_address with nonzero count.  */
344   bool accesses_prior_frames;
345 
346   /* Nonzero if the function calls __builtin_eh_return.  */
347   bool calls_eh_return;
348 
349   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
350      label that can reach the exit block via non-exceptional paths. */
351   bool saves_all_registers;
352 
353   /* Nonzero if function being compiled has nonlocal gotos to parent
354      function.  */
355   bool has_nonlocal_goto;
356 
357   /* Nonzero if function being compiled has an asm statement.  */
358   bool has_asm_statement;
359 
360   /* This bit is used by the exception handling logic.  It is set if all
361      calls (if any) are sibling calls.  Such functions do not have to
362      have EH tables generated, as they cannot throw.  A call to such a
363      function, however, should be treated as throwing if any of its callees
364      can throw.  */
365   bool all_throwers_are_sibcalls;
366 
367   /* Nonzero if stack limit checking should be enabled in the current
368      function.  */
369   bool limit_stack;
370 
371   /* Nonzero if profiling code should be generated.  */
372   bool profile;
373 
374   /* Nonzero if the current function uses the constant pool.  */
375   bool uses_const_pool;
376 
377   /* Nonzero if the current function uses pic_offset_table_rtx.  */
378   bool uses_pic_offset_table;
379 
380   /* Nonzero if the current function needs an lsda for exception handling.  */
381   bool uses_eh_lsda;
382 
383   /* Set when the tail call has been produced.  */
384   bool tail_call_emit;
385 
386   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
387   bool arg_pointer_save_area_init;
388 
389   /* Nonzero if current function must be given a frame pointer.
390      Set in reload1.c or lra-eliminations.c if anything is allocated
391      on the stack there.  */
392   bool frame_pointer_needed;
393 
394   /* When set, expand should optimize for speed.  */
395   bool maybe_hot_insn_p;
396 
397   /* Nonzero if function stack realignment is needed.  This flag may be
398      set twice: before and after reload.  It is set before reload wrt
399      stack alignment estimation before reload.  It will be changed after
400      reload if by then criteria of stack realignment is different.
401      The value set after reload is the accurate one and is finalized.  */
402   bool stack_realign_needed;
403 
404   /* Nonzero if function stack realignment is tried.  This flag is set
405      only once before reload.  It affects register elimination.  This
406      is used to generate DWARF debug info for stack variables.  */
407   bool stack_realign_tried;
408 
409   /* Nonzero if function being compiled needs dynamic realigned
410      argument pointer (drap) if stack needs realigning.  */
411   bool need_drap;
412 
413   /* Nonzero if function stack realignment estimation is done, namely
414      stack_realign_needed flag has been set before reload wrt estimated
415      stack alignment info.  */
416   bool stack_realign_processed;
417 
418   /* Nonzero if function stack realignment has been finalized, namely
419      stack_realign_needed flag has been set and finalized after reload.  */
420   bool stack_realign_finalized;
421 
422   /* True if dbr_schedule has already been called for this function.  */
423   bool dbr_scheduled_p;
424 
425   /* True if current function can not throw.  Unlike
426      TREE_NOTHROW (current_function_decl) it is set even for overwritable
427      function where currently compiled version of it is nothrow.  */
428   bool nothrow;
429 
430   /* True if we performed shrink-wrapping for the current function.  */
431   bool shrink_wrapped;
432 
433   /* Nonzero if function being compiled doesn't modify the stack pointer
434      (ignoring the prologue and epilogue).  This is only valid after
435      pass_stack_ptr_mod has run.  */
436   bool sp_is_unchanging;
437 
438   /* Nonzero if function being compiled doesn't contain any calls
439      (ignoring the prologue and epilogue).  This is set prior to
440      local register allocation and is valid for the remaining
441      compiler passes.  */
442   bool is_leaf;
443 
444   /* Nonzero if the function being compiled is a leaf function which only
445      uses leaf registers.  This is valid after reload (specifically after
446      sched2) and is useful only if the port defines LEAF_REGISTERS.  */
447   bool uses_only_leaf_regs;
448 
449   /* Like regs_ever_live, but 1 if a reg is set or clobbered from an
450      asm.  Unlike regs_ever_live, elements of this array corresponding
451      to eliminable regs (like the frame pointer) are set if an asm
452      sets them.  */
453   HARD_REG_SET asm_clobbers;
454 };
455 
456 #define return_label (crtl->x_return_label)
457 #define naked_return_label (crtl->x_naked_return_label)
458 #define stack_slot_list (crtl->x_stack_slot_list)
459 #define parm_birth_insn (crtl->x_parm_birth_insn)
460 #define frame_offset (crtl->x_frame_offset)
461 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
462 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
463 #define used_temp_slots (crtl->x_used_temp_slots)
464 #define avail_temp_slots (crtl->x_avail_temp_slots)
465 #define temp_slot_level (crtl->x_temp_slot_level)
466 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
467 #define frame_pointer_needed (crtl->frame_pointer_needed)
468 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
469 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
470 
471 extern GTY(()) struct rtl_data x_rtl;
472 
473 /* Accessor to RTL datastructures.  We keep them statically allocated now since
474    we never keep multiple functions.  For threaded compiler we might however
475    want to do differently.  */
476 #define crtl (&x_rtl)
477 
478 struct GTY(()) stack_usage
479 {
480   /* # of bytes of static stack space allocated by the function.  */
481   HOST_WIDE_INT static_stack_size;
482 
483   /* # of bytes of dynamic stack space allocated by the function.  This is
484      meaningful only if has_unbounded_dynamic_stack_size is zero.  */
485   HOST_WIDE_INT dynamic_stack_size;
486 
487   /* # of bytes of space pushed onto the stack after the prologue.  If
488      !ACCUMULATE_OUTGOING_ARGS, it contains the outgoing arguments.  */
489   int pushed_stack_size;
490 
491   /* Nonzero if the amount of stack space allocated dynamically cannot
492      be bounded at compile-time.  */
493   unsigned int has_unbounded_dynamic_stack_size : 1;
494 };
495 
496 #define current_function_static_stack_size (cfun->su->static_stack_size)
497 #define current_function_dynamic_stack_size (cfun->su->dynamic_stack_size)
498 #define current_function_pushed_stack_size (cfun->su->pushed_stack_size)
499 #define current_function_has_unbounded_dynamic_stack_size \
500   (cfun->su->has_unbounded_dynamic_stack_size)
501 #define current_function_allocates_dynamic_stack_space    \
502   (current_function_dynamic_stack_size != 0               \
503    || current_function_has_unbounded_dynamic_stack_size)
504 
505 /* This structure can save all the important global and static variables
506    describing the status of the current function.  */
507 
508 struct GTY(()) function {
509   struct eh_status *eh;
510 
511   /* The control flow graph for this function.  */
512   struct control_flow_graph *cfg;
513 
514   /* GIMPLE body for this function.  */
515   gimple_seq gimple_body;
516 
517   /* SSA and dataflow information.  */
518   struct gimple_df *gimple_df;
519 
520   /* The loops in this function.  */
521   struct loops *x_current_loops;
522 
523   /* The stack usage of this function.  */
524   struct stack_usage *su;
525 
526   /* Value histograms attached to particular statements.  */
527   htab_t GTY((skip)) value_histograms;
528 
529   /* For function.c.  */
530 
531   /* Points to the FUNCTION_DECL of this function.  */
532   tree decl;
533 
534   /* A PARM_DECL that should contain the static chain for this function.
535      It will be initialized at the beginning of the function.  */
536   tree static_chain_decl;
537 
538   /* An expression that contains the non-local goto save area.  The first
539      word is the saved frame pointer and the second is the saved stack
540      pointer.  */
541   tree nonlocal_goto_save_area;
542 
543   /* Vector of function local variables, functions, types and constants.  */
544   vec<tree, va_gc> *local_decls;
545 
546   /* For md files.  */
547 
548   /* tm.h can use this to store whatever it likes.  */
549   struct machine_function * GTY ((maybe_undef)) machine;
550 
551   /* Language-specific code can use this to store whatever it likes.  */
552   struct language_function * language;
553 
554   /* Used types hash table.  */
555   htab_t GTY ((param_is (union tree_node))) used_types_hash;
556 
557   /* Dwarf2 Frame Description Entry, containing the Call Frame Instructions
558      used for unwinding.  Only set when either dwarf2 unwinding or dwarf2
559      debugging is enabled.  */
560   struct dw_fde_struct *fde;
561 
562   /* Last statement uid.  */
563   int last_stmt_uid;
564 
565   /* Function sequence number for profiling, debugging, etc.  */
566   int funcdef_no;
567 
568   /* Line number of the start of the function for debugging purposes.  */
569   location_t function_start_locus;
570 
571   /* Line number of the end of the function.  */
572   location_t function_end_locus;
573 
574   /* Properties used by the pass manager.  */
575   unsigned int curr_properties;
576   unsigned int last_verified;
577 
578   /* Non-null if the function does something that would prevent it from
579      being copied; this applies to both versioning and inlining.  Set to
580      a string describing the reason for failure.  */
581   const char * GTY((skip)) cannot_be_copied_reason;
582 
583   /* Collected bit flags.  */
584 
585   /* Number of units of general registers that need saving in stdarg
586      function.  What unit is depends on the backend, either it is number
587      of bytes, or it can be number of registers.  */
588   unsigned int va_list_gpr_size : 8;
589 
590   /* Number of units of floating point registers that need saving in stdarg
591      function.  */
592   unsigned int va_list_fpr_size : 8;
593 
594   /* Nonzero if function being compiled can call setjmp.  */
595   unsigned int calls_setjmp : 1;
596 
597   /* Nonzero if function being compiled can call alloca,
598      either as a subroutine or builtin.  */
599   unsigned int calls_alloca : 1;
600 
601   /* Nonzero if function being compiled receives nonlocal gotos
602      from nested functions.  */
603   unsigned int has_nonlocal_label : 1;
604 
605   /* Nonzero if we've set cannot_be_copied_reason.  I.e. if
606      (cannot_be_copied_set && !cannot_be_copied_reason), the function
607      can in fact be copied.  */
608   unsigned int cannot_be_copied_set : 1;
609 
610   /* Nonzero if current function uses stdarg.h or equivalent.  */
611   unsigned int stdarg : 1;
612 
613   unsigned int after_inlining : 1;
614   unsigned int always_inline_functions_inlined : 1;
615 
616   /* Nonzero if function being compiled can throw synchronous non-call
617      exceptions.  */
618   unsigned int can_throw_non_call_exceptions : 1;
619 
620   /* Nonzero if instructions that may throw exceptions but don't otherwise
621      contribute to the execution of the program can be deleted.  */
622   unsigned int can_delete_dead_exceptions : 1;
623 
624   /* Fields below this point are not set for abstract functions; see
625      allocate_struct_function.  */
626 
627   /* Nonzero if function being compiled needs to be given an address
628      where the value should be stored.  */
629   unsigned int returns_struct : 1;
630 
631   /* Nonzero if function being compiled needs to
632      return the address of where it has put a structure value.  */
633   unsigned int returns_pcc_struct : 1;
634 
635   /* Nonzero if this function has local DECL_HARD_REGISTER variables.
636      In this case code motion has to be done more carefully.  */
637   unsigned int has_local_explicit_reg_vars : 1;
638 
639   /* Nonzero if the current function is a thunk, i.e., a lightweight
640      function implemented by the output_mi_thunk hook) that just
641      adjusts one of its arguments and forwards to another
642      function.  */
643   unsigned int is_thunk : 1;
644 };
645 
646 /* Add the decl D to the local_decls list of FUN.  */
647 
648 static inline void
add_local_decl(struct function * fun,tree d)649 add_local_decl (struct function *fun, tree d)
650 {
651   vec_safe_push (fun->local_decls, d);
652 }
653 
654 #define FOR_EACH_LOCAL_DECL(FUN, I, D)		\
655   FOR_EACH_VEC_SAFE_ELT_REVERSE ((FUN)->local_decls, I, D)
656 
657 /* If va_list_[gf]pr_size is set to this, it means we don't know how
658    many units need to be saved.  */
659 #define VA_LIST_MAX_GPR_SIZE	255
660 #define VA_LIST_MAX_FPR_SIZE	255
661 
662 /* The function currently being compiled.  */
663 extern GTY(()) struct function *cfun;
664 
665 /* In order to ensure that cfun is not set directly, we redefine it so
666    that it is not an lvalue.  Rather than assign to cfun, use
667    push_cfun or set_cfun.  */
668 #define cfun (cfun + 0)
669 
670 /* Nonzero if we've already converted virtual regs to hard regs.  */
671 extern int virtuals_instantiated;
672 
673 /* Nonzero if at least one trampoline has been created.  */
674 extern int trampolines_created;
675 
676 struct GTY(()) types_used_by_vars_entry {
677   tree type;
678   tree var_decl;
679 };
680 
681 /* Hash table making the relationship between a global variable
682    and the types it references in its initializer. The key of the
683    entry is a referenced type, and the value is the DECL of the global
684    variable. types_use_by_vars_do_hash and types_used_by_vars_eq below are
685    the hash and equality functions to use for this hash table.  */
686 extern GTY((param_is (struct types_used_by_vars_entry))) htab_t
687   types_used_by_vars_hash;
688 
689 hashval_t types_used_by_vars_do_hash (const void*);
690 int types_used_by_vars_eq (const void *, const void *);
691 void types_used_by_var_decl_insert (tree type, tree var_decl);
692 
693 /* During parsing of a global variable, this vector contains the types
694    referenced by the global variable.  */
695 extern GTY(()) vec<tree, va_gc> *types_used_by_cur_var_decl;
696 
697 /* cfun shouldn't be set directly; use one of these functions instead.  */
698 extern void set_cfun (struct function *new_cfun);
699 extern void push_cfun (struct function *new_cfun);
700 extern void pop_cfun (void);
701 extern void instantiate_decl_rtl (rtx x);
702 
703 /* For backward compatibility... eventually these should all go away.  */
704 #define current_function_funcdef_no (cfun->funcdef_no)
705 
706 #define current_loops (cfun->x_current_loops)
707 #define dom_computed (cfun->cfg->x_dom_computed)
708 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
709 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
710 
711 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
712    and create duplicate blocks.  */
713 extern void reorder_blocks (void);
714 
715 /* Set BLOCK_NUMBER for all the blocks in FN.  */
716 extern void number_blocks (tree);
717 
718 extern void clear_block_marks (tree);
719 extern tree blocks_nreverse (tree);
720 extern tree block_chainon (tree, tree);
721 
722 /* Return size needed for stack frame based on slots so far allocated.
723    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
724    the caller may have to do that.  */
725 extern HOST_WIDE_INT get_frame_size (void);
726 
727 /* Issue an error message and return TRUE if frame OFFSET overflows in
728    the signed target pointer arithmetics for function FUNC.  Otherwise
729    return FALSE.  */
730 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
731 
732 /* A pointer to a function to create target specific, per-function
733    data structures.  */
734 extern struct machine_function * (*init_machine_status) (void);
735 
736 /* Save and restore status information for a nested function.  */
737 extern void free_after_parsing (struct function *);
738 extern void free_after_compilation (struct function *);
739 
740 extern void init_varasm_status (void);
741 
742 #ifdef RTX_CODE
743 extern void diddle_return_value (void (*)(rtx, void*), void*);
744 extern void clobber_return_register (void);
745 #endif
746 
747 extern rtx get_arg_pointer_save_area (void);
748 
749 /* Returns the name of the current function.  */
750 extern const char *fndecl_name (tree);
751 extern const char *function_name (struct function *);
752 extern const char *current_function_name (void);
753 
754 extern void do_warn_unused_parameter (tree);
755 
756 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
757 			       tree, bool);
758 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
759 				     tree, bool);
760 
761 extern void used_types_insert (tree);
762 
763 extern int get_next_funcdef_no (void);
764 extern int get_last_funcdef_no (void);
765 
766 #ifdef HAVE_simple_return
767 extern bool requires_stack_frame_p (rtx, HARD_REG_SET, HARD_REG_SET);
768 #endif
769 
770 extern rtx get_hard_reg_initial_val (enum machine_mode, unsigned int);
771 extern rtx has_hard_reg_initial_val (enum machine_mode, unsigned int);
772 extern rtx get_hard_reg_initial_reg (rtx);
773 extern bool initial_value_entry (int i, rtx *, rtx *);
774 
775 /* Called from gimple_expand_cfg.  */
776 extern unsigned int emit_initial_value_sets (void);
777 
778 /* In predict.c */
779 extern bool optimize_function_for_size_p (struct function *);
780 extern bool optimize_function_for_speed_p (struct function *);
781 
782 #endif  /* GCC_FUNCTION_H */
783