gcc/function.h

   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, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   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
  11 version.
  12
  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
  16 for more details.
  17
  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/>.  */
  21
  22 #ifndef GCC_FUNCTION_H
  23 #define GCC_FUNCTION_H
  24
  25 #include "tree.h"
  26 #include "hashtab.h"
  27 #include "vecprim.h"
  28 #include "tm.h"         /* For CUMULATIVE_ARGS.  */
  29 #include "hard-reg-set.h"
  30
  31 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
  32    Each element describes one pending sequence.
  33    The main insn-chain is saved in the last element of the chain,
  34    unless the chain is empty.  */
  35
  36 struct GTY(()) sequence_stack {
  37   /* First and last insns in the chain of the saved sequence.  */
  38   rtx first;
  39   rtx last;
  40   struct sequence_stack *next;
  41 };
  42 \f
  43 struct GTY(()) emit_status {
  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.  */
  46   int x_reg_rtx_no;
  47
  48   /* Lowest label number in current function.  */
  49   int x_first_label_num;
  50
  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.
  53
  54      start_sequence saves both of these on `sequence_stack' and then starts
  55      a new, nested sequence of insns.  */
  56   rtx x_first_insn;
  57   rtx x_last_insn;
  58
  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;
  64
  65   /* INSN_UID for next insn emitted.
  66      Reset to 1 for each function compiled.  */
  67   int x_cur_insn_uid;
  68
  69   /* INSN_UID for next debug insn emitted.  Only used if
  70      --param min-nondebug-insn-uid=<value> is given with nonzero value.  */
  71   int x_cur_debug_insn_uid;
  72
  73   /* Location the last line-number NOTE emitted.
  74      This is used to avoid generating duplicates.  */
  75   location_t x_last_location;
  76
  77   /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
  78      vectors.  Since these vectors are needed during the expansion phase when
  79      the total number of registers in the function is not yet known, the
  80      vectors are copied and made bigger when necessary.  */
  81   int regno_pointer_align_length;
  82
  83   /* Indexed by pseudo register number, if nonzero gives the known alignment
  84      for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
  85      Allocated in parallel with x_regno_reg_rtx.  */
  86   unsigned char * GTY((skip)) regno_pointer_align;
  87 };
  88
  89
  90 /* Indexed by pseudo register number, gives the rtx for that pseudo.
  91    Allocated in parallel with regno_pointer_align.
  92    FIXME: We could put it into emit_status struct, but gengtype is not able to deal
  93    with length attribute nested in top level structures.  */
  94
  95 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx * regno_reg_rtx;
  96
  97 /* For backward compatibility... eventually these should all go away.  */
  98 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
  99 #define seq_stack (crtl->emit.sequence_stack)
 100
 101 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
 102
 103 struct GTY(()) expr_status {
 104   /* Number of units that we should eventually pop off the stack.
 105      These are the arguments to function calls that have already returned.  */
 106   int x_pending_stack_adjust;
 107
 108   /* Under some ABIs, it is the caller's responsibility to pop arguments
 109      pushed for function calls.  A naive implementation would simply pop
 110      the arguments immediately after each call.  However, if several
 111      function calls are made in a row, it is typically cheaper to pop
 112      all the arguments after all of the calls are complete since a
 113      single pop instruction can be used.  Therefore, GCC attempts to
 114      defer popping the arguments until absolutely necessary.  (For
 115      example, at the end of a conditional, the arguments must be popped,
 116      since code outside the conditional won't know whether or not the
 117      arguments need to be popped.)
 118
 119      When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
 120      attempt to defer pops.  Instead, the stack is popped immediately
 121      after each call.  Rather then setting this variable directly, use
 122      NO_DEFER_POP and OK_DEFER_POP.  */
 123   int x_inhibit_defer_pop;
 124
 125   /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
 126      boundary can be momentarily unaligned while pushing the arguments.
 127      Record the delta since last aligned boundary here in order to get
 128      stack alignment in the nested function calls working right.  */
 129   int x_stack_pointer_delta;
 130
 131   /* Nonzero means __builtin_saveregs has already been done in this function.
 132      The value is the pseudoreg containing the value __builtin_saveregs
 133      returned.  */
 134   rtx x_saveregs_value;
 135
 136   /* Similarly for __builtin_apply_args.  */
 137   rtx x_apply_args_value;
 138
 139   /* List of labels that must never be deleted.  */
 140   rtx x_forced_labels;
 141 };
 142
 143 typedef struct call_site_record_d *call_site_record;
 144 DEF_VEC_P(call_site_record);
 145 DEF_VEC_ALLOC_P(call_site_record, gc);
 146
 147 /* RTL representation of exception handling.  */
 148 struct GTY(()) rtl_eh {
 149   rtx ehr_stackadj;
 150   rtx ehr_handler;
 151   rtx ehr_label;
 152
 153   rtx sjlj_fc;
 154   rtx sjlj_exit_after;
 155
 156   VEC(uchar,gc) *action_record_data;
 157
 158   VEC(call_site_record,gc) *call_site_record[2];
 159 };
 160
 161 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
 162 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
 163 #define saveregs_value (crtl->expr.x_saveregs_value)
 164 #define apply_args_value (crtl->expr.x_apply_args_value)
 165 #define forced_labels (crtl->expr.x_forced_labels)
 166 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
 167
 168 struct gimple_df;
 169 struct temp_slot;
 170 typedef struct temp_slot *temp_slot_p;
 171 struct call_site_record_d;
 172
 173 DEF_VEC_P(temp_slot_p);
 174 DEF_VEC_ALLOC_P(temp_slot_p,gc);
 175 struct ipa_opt_pass_d;
 176 typedef struct ipa_opt_pass_d *ipa_opt_pass;
 177
 178 DEF_VEC_P(ipa_opt_pass);
 179 DEF_VEC_ALLOC_P(ipa_opt_pass,heap);
 180
 181 struct GTY(()) varasm_status {
 182   /* If we're using a per-function constant pool, this is it.  */
 183   struct rtx_constant_pool *pool;
 184
 185   /* Number of tree-constants deferred during the expansion of this
 186      function.  */
 187   unsigned int deferred_constants;
 188 };
 189
 190 /* Information mainlined about RTL representation of incoming arguments.  */
 191 struct GTY(()) incoming_args {
 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.  */
 195   int pops_args;
 196
 197   /* If function's args have a fixed size, this is that size, in bytes.
 198      Otherwise, it is -1.
 199      May affect compilation of return insn or of function epilogue.  */
 200   int size;
 201
 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
 204      registers.  */
 205   int pretend_args_size;
 206
 207   /* This is the offset from the arg pointer to the place where the first
 208      anonymous arg can be found, if there is one.  */
 209   rtx arg_offset_rtx;
 210
 211   /* Quantities of various kinds of registers
 212      used for the current function's args.  */
 213   CUMULATIVE_ARGS info;
 214
 215   /* The arg pointer hard register, or the pseudo into which it was copied.  */
 216   rtx internal_arg_pointer;
 217 };
 218
 219 /* Data for function partitioning.  */
 220 struct GTY(()) function_subsections {
 221   /* Assembly labels for the hot and cold text sections, to
 222      be used by debugger functions for determining the size of text
 223      sections.  */
 224
 225   const char *hot_section_label;
 226   const char *cold_section_label;
 227   const char *hot_section_end_label;
 228   const char *cold_section_end_label;
 229 };
 230
 231 /* Describe an empty area of space in the stack frame.  These can be chained
 232    into a list; this is used to keep track of space wasted for alignment
 233    reasons.  */
 234 struct GTY(()) frame_space
 235 {
 236   struct frame_space *next;
 237
 238   HOST_WIDE_INT start;
 239   HOST_WIDE_INT length;
 240 };
 241
 242 /* Datastructures maintained for currently processed function in RTL form.  */
 243 struct GTY(()) rtl_data {
 244   struct expr_status expr;
 245   struct emit_status emit;
 246   struct varasm_status varasm;
 247   struct incoming_args args;
 248   struct function_subsections subsections;
 249   struct rtl_eh eh;
 250
 251   /* For function.c  */
 252
 253   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
 254      defined, the needed space is pushed by the prologue.  */
 255   int outgoing_args_size;
 256
 257   /* If nonzero, an RTL expression for the location at which the current
 258      function returns its result.  If the current function returns its
 259      result in a register, current_function_return_rtx will always be
 260      the hard register containing the result.  */
 261   rtx return_rtx;
 262
 263   /* Opaque pointer used by get_hard_reg_initial_val and
 264      has_hard_reg_initial_val (see integrate.[hc]).  */
 265   struct initial_value_struct *hard_reg_initial_vals;
 266
 267   /* A variable living at the top of the frame that holds a known value.
 268      Used for detecting stack clobbers.  */
 269   tree stack_protect_guard;
 270
 271   /* List (chain of EXPR_LIST) of labels heading the current handlers for
 272      nonlocal gotos.  */
 273   rtx x_nonlocal_goto_handler_labels;
 274
 275   /* Label that will go on function epilogue.
 276      Jumping to this label serves as a "return" instruction
 277      on machines which require execution of the epilogue on all returns.  */
 278   rtx x_return_label;
 279
 280   /* Label that will go on the end of function epilogue.
 281      Jumping to this label serves as a "naked return" instruction
 282      on machines which require execution of the epilogue on all returns.  */
 283   rtx x_naked_return_label;
 284
 285   /* List (chain of EXPR_LISTs) of all stack slots in this function.
 286      Made for the sake of unshare_all_rtl.  */
 287   rtx x_stack_slot_list;
 288
 289   /* List of empty areas in the stack frame.  */
 290   struct frame_space *frame_space_list;
 291
 292   /* Place after which to insert the tail_recursion_label if we need one.  */
 293   rtx x_stack_check_probe_note;
 294
 295   /* Location at which to save the argument pointer if it will need to be
 296      referenced.  There are two cases where this is done: if nonlocal gotos
 297      exist, or if vars stored at an offset from the argument pointer will be
 298      needed by inner routines.  */
 299   rtx x_arg_pointer_save_area;
 300
 301   /* Dynamic Realign Argument Pointer used for realigning stack.  */
 302   rtx drap_reg;
 303
 304   /* Offset to end of allocated area of stack frame.
 305      If stack grows down, this is the address of the last stack slot allocated.
 306      If stack grows up, this is the address for the next slot.  */
 307   HOST_WIDE_INT x_frame_offset;
 308
 309   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
 310   rtx x_parm_birth_insn;
 311
 312   /* List of all used temporaries allocated, by level.  */
 313   VEC(temp_slot_p,gc) *x_used_temp_slots;
 314
 315   /* List of available temp slots.  */
 316   struct temp_slot *x_avail_temp_slots;
 317
 318   /* Current nesting level for temporaries.  */
 319   int x_temp_slot_level;
 320
 321   /* The largest alignment needed on the stack, including requirement
 322      for outgoing stack alignment.  */
 323   unsigned int stack_alignment_needed;
 324
 325   /* Preferred alignment of the end of stack frame, which is preferred
 326      to call other functions.  */
 327   unsigned int preferred_stack_boundary;
 328
 329   /* The minimum alignment of parameter stack.  */
 330   unsigned int parm_stack_boundary;
 331
 332   /* The largest alignment of slot allocated on the stack.  */
 333   unsigned int max_used_stack_slot_alignment;
 334
 335   /* The stack alignment estimated before reload, with consideration of
 336      following factors:
 337      1. Alignment of local stack variables (max_used_stack_slot_alignment)
 338      2. Alignment requirement to call other functions
 339         (preferred_stack_boundary)
 340      3. Alignment of non-local stack variables but might be spilled in
 341         local stack.  */
 342   unsigned int stack_alignment_estimated;
 343
 344   /* For reorg.  */
 345
 346   /* If some insns can be deferred to the delay slots of the epilogue, the
 347      delay list for them is recorded here.  */
 348   rtx epilogue_delay_list;
 349
 350   /* Nonzero if function being compiled called builtin_return_addr or
 351      builtin_frame_address with nonzero count.  */
 352   bool accesses_prior_frames;
 353
 354   /* Nonzero if the function calls __builtin_eh_return.  */
 355   bool calls_eh_return;
 356
 357   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
 358      label that can reach the exit block via non-exceptional paths. */
 359   bool saves_all_registers;
 360
 361   /* Nonzero if function being compiled has nonlocal gotos to parent
 362      function.  */
 363   bool has_nonlocal_goto;
 364
 365   /* Nonzero if function being compiled has an asm statement.  */
 366   bool has_asm_statement;
 367
 368   /* This bit is used by the exception handling logic.  It is set if all
 369      calls (if any) are sibling calls.  Such functions do not have to
 370      have EH tables generated, as they cannot throw.  A call to such a
 371      function, however, should be treated as throwing if any of its callees
 372      can throw.  */
 373   bool all_throwers_are_sibcalls;
 374
 375   /* Nonzero if stack limit checking should be enabled in the current
 376      function.  */
 377   bool limit_stack;
 378
 379   /* Nonzero if profiling code should be generated.  */
 380   bool profile;
 381
 382   /* Nonzero if the current function uses the constant pool.  */
 383   bool uses_const_pool;
 384
 385   /* Nonzero if the current function uses pic_offset_table_rtx.  */
 386   bool uses_pic_offset_table;
 387
 388   /* Nonzero if the current function needs an lsda for exception handling.  */
 389   bool uses_eh_lsda;
 390
 391   /* Set when the tail call has been produced.  */
 392   bool tail_call_emit;
 393
 394   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
 395   bool arg_pointer_save_area_init;
 396
 397   /* Nonzero if current function must be given a frame pointer.
 398      Set in global.c if anything is allocated on the stack there.  */
 399   bool frame_pointer_needed;
 400
 401   /* When set, expand should optimize for speed.  */
 402   bool maybe_hot_insn_p;
 403
 404   /* Nonzero if function stack realignment is needed.  This flag may be
 405      set twice: before and after reload.  It is set before reload wrt
 406      stack alignment estimation before reload.  It will be changed after
 407      reload if by then criteria of stack realignment is different.
 408      The value set after reload is the accurate one and is finalized.  */
 409   bool stack_realign_needed;
 410
 411   /* Nonzero if function stack realignment is tried.  This flag is set
 412      only once before reload.  It affects register elimination.  This
 413      is used to generate DWARF debug info for stack variables.  */
 414   bool stack_realign_tried;
 415
 416   /* Nonzero if function being compiled needs dynamic realigned
 417      argument pointer (drap) if stack needs realigning.  */
 418   bool need_drap;
 419
 420   /* Nonzero if function stack realignment estimation is done, namely
 421      stack_realign_needed flag has been set before reload wrt estimated
 422      stack alignment info.  */
 423   bool stack_realign_processed;
 424
 425   /* Nonzero if function stack realignment has been finalized, namely
 426      stack_realign_needed flag has been set and finalized after reload.  */
 427   bool stack_realign_finalized;
 428
 429   /* True if dbr_schedule has already been called for this function.  */
 430   bool dbr_scheduled_p;
 431
 432   /* True if current function can not throw.  Unlike
 433      TREE_NOTHROW (current_function_decl) it is set even for overwritable
 434      function where currently compiled version of it is nothrow.  */
 435   bool nothrow;
 436
 437   /* Like regs_ever_live, but 1 if a reg is set or clobbered from an
 438      asm.  Unlike regs_ever_live, elements of this array corresponding
 439      to eliminable regs (like the frame pointer) are set if an asm
 440      sets them.  */
 441   HARD_REG_SET asm_clobbers;
 442 };
 443
 444 #define return_label (crtl->x_return_label)
 445 #define naked_return_label (crtl->x_naked_return_label)
 446 #define stack_slot_list (crtl->x_stack_slot_list)
 447 #define parm_birth_insn (crtl->x_parm_birth_insn)
 448 #define frame_offset (crtl->x_frame_offset)
 449 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
 450 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
 451 #define used_temp_slots (crtl->x_used_temp_slots)
 452 #define avail_temp_slots (crtl->x_avail_temp_slots)
 453 #define temp_slot_level (crtl->x_temp_slot_level)
 454 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
 455 #define frame_pointer_needed (crtl->frame_pointer_needed)
 456 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
 457 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
 458
 459 extern GTY(()) struct rtl_data x_rtl;
 460
 461 /* Accessor to RTL datastructures.  We keep them statically allocated now since
 462    we never keep multiple functions.  For threaded compiler we might however
 463    want to do differently.  */
 464 #define crtl (&x_rtl)
 465
 466 struct GTY(()) stack_usage
 467 {
 468   /* # of bytes of static stack space allocated by the function.  */
 469   HOST_WIDE_INT static_stack_size;
 470
 471   /* # of bytes of dynamic stack space allocated by the function.  This is
 472      meaningful only if has_unbounded_dynamic_stack_size is zero.  */
 473   HOST_WIDE_INT dynamic_stack_size;
 474
 475   /* # of bytes of space pushed onto the stack after the prologue.  If
 476      !ACCUMULATE_OUTGOING_ARGS, it contains the outgoing arguments.  */
 477   int pushed_stack_size;
 478
 479   /* # of dynamic allocations in the function.  */
 480   unsigned int dynamic_alloc_count : 31;
 481
 482   /* Nonzero if the amount of stack space allocated dynamically cannot
 483      be bounded at compile-time.  */
 484   unsigned int has_unbounded_dynamic_stack_size : 1;
 485 };
 486
 487 #define current_function_static_stack_size (cfun->su->static_stack_size)
 488 #define current_function_dynamic_stack_size (cfun->su->dynamic_stack_size)
 489 #define current_function_pushed_stack_size (cfun->su->pushed_stack_size)
 490 #define current_function_dynamic_alloc_count (cfun->su->dynamic_alloc_count)
 491 #define current_function_has_unbounded_dynamic_stack_size \
 492   (cfun->su->has_unbounded_dynamic_stack_size)
 493 #define current_function_allocates_dynamic_stack_space    \
 494   (current_function_dynamic_stack_size != 0               \
 495    || current_function_has_unbounded_dynamic_stack_size)
 496
 497 /* This structure can save all the important global and static variables
 498    describing the status of the current function.  */
 499
 500 struct GTY(()) function {
 501   struct eh_status *eh;
 502
 503   /* The control flow graph for this function.  */
 504   struct control_flow_graph *cfg;
 505
 506   /* GIMPLE body for this function.  */
 507   struct gimple_seq_d *gimple_body;
 508
 509   /* SSA and dataflow information.  */
 510   struct gimple_df *gimple_df;
 511
 512   /* The loops in this function.  */
 513   struct loops *x_current_loops;
 514
 515   /* The stack usage of this function.  */
 516   struct stack_usage *su;
 517
 518   /* Value histograms attached to particular statements.  */
 519   htab_t GTY((skip)) value_histograms;
 520
 521   /* For function.c.  */
 522
 523   /* Points to the FUNCTION_DECL of this function.  */
 524   tree decl;
 525
 526   /* A PARM_DECL that should contain the static chain for this function.
 527      It will be initialized at the beginning of the function.  */
 528   tree static_chain_decl;
 529
 530   /* An expression that contains the non-local goto save area.  The first
 531      word is the saved frame pointer and the second is the saved stack
 532      pointer.  */
 533   tree nonlocal_goto_save_area;
 534
 535   /* Vector of function local variables, functions, types and constants.  */
 536   VEC(tree,gc) *local_decls;
 537
 538   /* For md files.  */
 539
 540   /* tm.h can use this to store whatever it likes.  */
 541   struct machine_function * GTY ((maybe_undef)) machine;
 542
 543   /* Language-specific code can use this to store whatever it likes.  */
 544   struct language_function * language;
 545
 546   /* Used types hash table.  */
 547   htab_t GTY ((param_is (union tree_node))) used_types_hash;
 548
 549   /* Last statement uid.  */
 550   int last_stmt_uid;
 551
 552   /* Function sequence number for profiling, debugging, etc.  */
 553   int funcdef_no;
 554
 555   /* Line number of the start of the function for debugging purposes.  */
 556   location_t function_start_locus;
 557
 558   /* Line number of the end of the function.  */
 559   location_t function_end_locus;
 560
 561   /* Properties used by the pass manager.  */
 562   unsigned int curr_properties;
 563   unsigned int last_verified;
 564
 565   /* Non-null if the function does something that would prevent it from
 566      being copied; this applies to both versioning and inlining.  Set to
 567      a string describing the reason for failure.  */
 568   const char * GTY((skip)) cannot_be_copied_reason;
 569
 570   /* Collected bit flags.  */
 571
 572   /* Number of units of general registers that need saving in stdarg
 573      function.  What unit is depends on the backend, either it is number
 574      of bytes, or it can be number of registers.  */
 575   unsigned int va_list_gpr_size : 8;
 576
 577   /* Number of units of floating point registers that need saving in stdarg
 578      function.  */
 579   unsigned int va_list_fpr_size : 8;
 580
 581   /* Nonzero if function being compiled can call setjmp.  */
 582   unsigned int calls_setjmp : 1;
 583
 584   /* Nonzero if function being compiled can call alloca,
 585      either as a subroutine or builtin.  */
 586   unsigned int calls_alloca : 1;
 587
 588   /* Nonzero if function being compiled receives nonlocal gotos
 589      from nested functions.  */
 590   unsigned int has_nonlocal_label : 1;
 591
 592   /* Nonzero if we've set cannot_be_copied_reason.  I.e. if
 593      (cannot_be_copied_set && !cannot_be_copied_reason), the function
 594      can in fact be copied.  */
 595   unsigned int cannot_be_copied_set : 1;
 596
 597   /* Nonzero if current function uses stdarg.h or equivalent.  */
 598   unsigned int stdarg : 1;
 599
 600   unsigned int after_inlining : 1;
 601   unsigned int always_inline_functions_inlined : 1;
 602
 603   /* Nonzero if function being compiled can throw synchronous non-call
 604      exceptions.  */
 605   unsigned int can_throw_non_call_exceptions : 1;
 606
 607   /* Fields below this point are not set for abstract functions; see
 608      allocate_struct_function.  */
 609
 610   /* Nonzero if function being compiled needs to be given an address
 611      where the value should be stored.  */
 612   unsigned int returns_struct : 1;
 613
 614   /* Nonzero if function being compiled needs to
 615      return the address of where it has put a structure value.  */
 616   unsigned int returns_pcc_struct : 1;
 617
 618   /* Nonzero if pass_tree_profile was run on this function.  */
 619   unsigned int after_tree_profile : 1;
 620
 621   /* Nonzero if this function has local DECL_HARD_REGISTER variables.
 622      In this case code motion has to be done more carefully.  */
 623   unsigned int has_local_explicit_reg_vars : 1;
 624
 625   /* Nonzero if the current function is a thunk, i.e., a lightweight
 626      function implemented by the output_mi_thunk hook) that just
 627      adjusts one of its arguments and forwards to another
 628      function.  */
 629   unsigned int is_thunk : 1;
 630 };
 631
 632 /* Add the decl D to the local_decls list of FUN.  */
 633
 634 static inline void
 635 add_local_decl (struct function *fun, tree d)
 636 {
 637   VEC_safe_push (tree, gc, fun->local_decls, d);
 638 }
 639
 640 #define FOR_EACH_LOCAL_DECL(FUN, I, D)          \
 641   FOR_EACH_VEC_ELT_REVERSE (tree, (FUN)->local_decls, I, D)
 642
 643 /* If va_list_[gf]pr_size is set to this, it means we don't know how
 644    many units need to be saved.  */
 645 #define VA_LIST_MAX_GPR_SIZE    255
 646 #define VA_LIST_MAX_FPR_SIZE    255
 647
 648 /* The function currently being compiled.  */
 649 extern GTY(()) struct function *cfun;
 650
 651 /* In order to ensure that cfun is not set directly, we redefine it so
 652    that it is not an lvalue.  Rather than assign to cfun, use
 653    push_cfun or set_cfun.  */
 654 #define cfun (cfun + 0)
 655
 656 /* Nonzero if we've already converted virtual regs to hard regs.  */
 657 extern int virtuals_instantiated;
 658
 659 /* Nonzero if at least one trampoline has been created.  */
 660 extern int trampolines_created;
 661
 662 struct GTY(()) types_used_by_vars_entry {
 663   tree type;
 664   tree var_decl;
 665 };
 666
 667 /* Hash table making the relationship between a global variable
 668    and the types it references in its initializer. The key of the
 669    entry is a referenced type, and the value is the DECL of the global
 670    variable. types_use_by_vars_do_hash and types_used_by_vars_eq below are
 671    the hash and equality functions to use for this hash table.  */
 672 extern GTY((param_is (struct types_used_by_vars_entry))) htab_t
 673   types_used_by_vars_hash;
 674
 675 hashval_t types_used_by_vars_do_hash (const void*);
 676 int types_used_by_vars_eq (const void *, const void *);
 677 void types_used_by_var_decl_insert (tree type, tree var_decl);
 678
 679 /* During parsing of a global variable, this vector contains the types
 680    referenced by the global variable.  */
 681 extern GTY(()) VEC(tree,gc) *types_used_by_cur_var_decl;
 682
 683
 684 /* cfun shouldn't be set directly; use one of these functions instead.  */
 685 extern void set_cfun (struct function *new_cfun);
 686 extern void push_cfun (struct function *new_cfun);
 687 extern void pop_cfun (void);
 688 extern void instantiate_decl_rtl (rtx x);
 689
 690 /* For backward compatibility... eventually these should all go away.  */
 691 #define current_function_funcdef_no (cfun->funcdef_no)
 692
 693 #define current_loops (cfun->x_current_loops)
 694 #define dom_computed (cfun->cfg->x_dom_computed)
 695 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
 696 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
 697
 698 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
 699    and create duplicate blocks.  */
 700 extern void reorder_blocks (void);
 701
 702 /* Set BLOCK_NUMBER for all the blocks in FN.  */
 703 extern void number_blocks (tree);
 704
 705 extern void clear_block_marks (tree);
 706 extern tree blocks_nreverse (tree);
 707 extern tree block_chainon (tree, tree);
 708
 709 /* Return size needed for stack frame based on slots so far allocated.
 710    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
 711    the caller may have to do that.  */
 712 extern HOST_WIDE_INT get_frame_size (void);
 713
 714 /* Issue an error message and return TRUE if frame OFFSET overflows in
 715    the signed target pointer arithmetics for function FUNC.  Otherwise
 716    return FALSE.  */
 717 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
 718
 719 /* A pointer to a function to create target specific, per-function
 720    data structures.  */
 721 extern struct machine_function * (*init_machine_status) (void);
 722
 723 /* Save and restore status information for a nested function.  */
 724 extern void free_after_parsing (struct function *);
 725 extern void free_after_compilation (struct function *);
 726
 727 extern void init_varasm_status (void);
 728
 729 #ifdef RTX_CODE
 730 extern void diddle_return_value (void (*)(rtx, void*), void*);
 731 extern void clobber_return_register (void);
 732 #endif
 733
 734 extern rtx get_arg_pointer_save_area (void);
 735
 736 /* Returns the name of the current function.  */
 737 extern const char *current_function_name (void);
 738
 739 extern void do_warn_unused_parameter (tree);
 740
 741 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
 742                                tree, bool);
 743 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
 744                                      tree, bool);
 745
 746 extern void used_types_insert (tree);
 747
 748 extern int get_next_funcdef_no (void);
 749 extern int get_last_funcdef_no (void);
 750
 751 /* In predict.c */
 752 extern bool optimize_function_for_size_p (struct function *);
 753 extern bool optimize_function_for_speed_p (struct function *);
 754
 755 #endif  /* GCC_FUNCTION_H */