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
   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
  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.  */
  33
  34 struct GTY(()) sequence_stack {
  35   /* First and last insns in the chain of the saved sequence.  */
  36   rtx first;
  37   rtx last;
  38   struct sequence_stack *next;
  39 };
  40 \f
  41 struct GTY(()) emit_status {
  42   /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
  43      After rtl generation, it is 1 plus the largest register number used.  */
  44   int x_reg_rtx_no;
  45
  46   /* Lowest label number in current function.  */
  47   int x_first_label_num;
  48
  49   /* The ends of the doubly-linked chain of rtl for the current function.
  50      Both are reset to null at the start of rtl generation for the function.
  51
  52      start_sequence saves both of these on `sequence_stack' and then starts
  53      a new, nested sequence of insns.  */
  54   rtx x_first_insn;
  55   rtx x_last_insn;
  56
  57   /* Stack of pending (incomplete) sequences saved by `start_sequence'.
  58      Each element describes one pending sequence.
  59      The main insn-chain is saved in the last element of the chain,
  60      unless the chain is empty.  */
  61   struct sequence_stack *sequence_stack;
  62
  63   /* INSN_UID for next insn emitted.
  64      Reset to 1 for each function compiled.  */
  65   int x_cur_insn_uid;
  66
  67   /* INSN_UID for next debug insn emitted.  Only used if
  68      --param min-nondebug-insn-uid=<value> is given with nonzero value.  */
  69   int x_cur_debug_insn_uid;
  70
  71   /* Location the last line-number NOTE emitted.
  72      This is used to avoid generating duplicates.  */
  73   location_t x_last_location;
  74
  75   /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
  76      vectors.  Since these vectors are needed during the expansion phase when
  77      the total number of registers in the function is not yet known, the
  78      vectors are copied and made bigger when necessary.  */
  79   int regno_pointer_align_length;
  80
  81   /* Indexed by pseudo register number, if nonzero gives the known alignment
  82      for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
  83      Allocated in parallel with x_regno_reg_rtx.  */
  84   unsigned char * GTY((skip)) regno_pointer_align;
  85 };
  86
  87
  88 /* Indexed by pseudo register number, gives the rtx for that pseudo.
  89    Allocated in parallel with regno_pointer_align.
  90    FIXME: We could put it into emit_status struct, but gengtype is not able to deal
  91    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 DEF_VEC_P(call_site_record);
 143 DEF_VEC_ALLOC_P(call_site_record, gc);
 144
 145 /* RTL representation of exception handling.  */
 146 struct GTY(()) rtl_eh {
 147   rtx ehr_stackadj;
 148   rtx ehr_handler;
 149   rtx ehr_label;
 150
 151   rtx sjlj_fc;
 152   rtx sjlj_exit_after;
 153
 154   VEC(uchar,gc) *action_record_data;
 155
 156   VEC(call_site_record,gc) *call_site_record[2];
 157 };
 158
 159 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
 160 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
 161 #define saveregs_value (crtl->expr.x_saveregs_value)
 162 #define apply_args_value (crtl->expr.x_apply_args_value)
 163 #define forced_labels (crtl->expr.x_forced_labels)
 164 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
 165
 166 struct gimple_df;
 167 struct temp_slot;
 168 typedef struct temp_slot *temp_slot_p;
 169 struct call_site_record_d;
 170
 171 DEF_VEC_P(temp_slot_p);
 172 DEF_VEC_ALLOC_P(temp_slot_p,gc);
 173 struct ipa_opt_pass_d;
 174 typedef struct ipa_opt_pass_d *ipa_opt_pass;
 175
 176 DEF_VEC_P(ipa_opt_pass);
 177 DEF_VEC_ALLOC_P(ipa_opt_pass,heap);
 178
 179 struct GTY(()) varasm_status {
 180   /* If we're using a per-function constant pool, this is it.  */
 181   struct rtx_constant_pool *pool;
 182
 183   /* Number of tree-constants deferred during the expansion of this
 184      function.  */
 185   unsigned int deferred_constants;
 186 };
 187
 188 /* Information mainlined about RTL representation of incoming arguments.  */
 189 struct GTY(()) incoming_args {
 190   /* Number of bytes of args popped by function being compiled on its return.
 191      Zero if no bytes are to be popped.
 192      May affect compilation of return insn or of function epilogue.  */
 193   int pops_args;
 194
 195   /* If function's args have a fixed size, this is that size, in bytes.
 196      Otherwise, it is -1.
 197      May affect compilation of return insn or of function epilogue.  */
 198   int size;
 199
 200   /* # bytes the prologue should push and pretend that the caller pushed them.
 201      The prologue must do this, but only if parms can be passed in
 202      registers.  */
 203   int pretend_args_size;
 204
 205   /* This is the offset from the arg pointer to the place where the first
 206      anonymous arg can be found, if there is one.  */
 207   rtx arg_offset_rtx;
 208
 209   /* Quantities of various kinds of registers
 210      used for the current function's args.  */
 211   CUMULATIVE_ARGS info;
 212
 213   /* The arg pointer hard register, or the pseudo into which it was copied.  */
 214   rtx internal_arg_pointer;
 215 };
 216
 217 /* Data for function partitioning.  */
 218 struct GTY(()) function_subsections {
 219   /* Assembly labels for the hot and cold text sections, to
 220      be used by debugger functions for determining the size of text
 221      sections.  */
 222
 223   const char *hot_section_label;
 224   const char *cold_section_label;
 225   const char *hot_section_end_label;
 226   const char *cold_section_end_label;
 227
 228   /* String to be used for name of cold text sections, via
 229      targetm.asm_out.named_section.  */
 230
 231   const char *unlikely_text_section_name;
 232 };
 233
 234 /* Datastructures maintained for currently processed function in RTL form.  */
 235 struct GTY(()) rtl_data {
 236   struct expr_status expr;
 237   struct emit_status emit;
 238   struct varasm_status varasm;
 239   struct incoming_args args;
 240   struct function_subsections subsections;
 241   struct rtl_eh eh;
 242
 243   /* For function.c  */
 244
 245   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
 246      defined, the needed space is pushed by the prologue.  */
 247   int outgoing_args_size;
 248
 249   /* If nonzero, an RTL expression for the location at which the current
 250      function returns its result.  If the current function returns its
 251      result in a register, current_function_return_rtx will always be
 252      the hard register containing the result.  */
 253   rtx return_rtx;
 254
 255   /* Opaque pointer used by get_hard_reg_initial_val and
 256      has_hard_reg_initial_val (see integrate.[hc]).  */
 257   struct initial_value_struct *hard_reg_initial_vals;
 258
 259   /* A variable living at the top of the frame that holds a known value.
 260      Used for detecting stack clobbers.  */
 261   tree stack_protect_guard;
 262
 263   /* List (chain of EXPR_LIST) of labels heading the current handlers for
 264      nonlocal gotos.  */
 265   rtx x_nonlocal_goto_handler_labels;
 266
 267   /* Label that will go on function epilogue.
 268      Jumping to this label serves as a "return" instruction
 269      on machines which require execution of the epilogue on all returns.  */
 270   rtx x_return_label;
 271
 272   /* Label that will go on the end of function epilogue.
 273      Jumping to this label serves as a "naked return" instruction
 274      on machines which require execution of the epilogue on all returns.  */
 275   rtx x_naked_return_label;
 276
 277   /* List (chain of EXPR_LISTs) of all stack slots in this function.
 278      Made for the sake of unshare_all_rtl.  */
 279   rtx x_stack_slot_list;
 280
 281   /* Place after which to insert the tail_recursion_label if we need one.  */
 282   rtx x_stack_check_probe_note;
 283
 284   /* Location at which to save the argument pointer if it will need to be
 285      referenced.  There are two cases where this is done: if nonlocal gotos
 286      exist, or if vars stored at an offset from the argument pointer will be
 287      needed by inner routines.  */
 288   rtx x_arg_pointer_save_area;
 289
 290   /* Dynamic Realign Argument Pointer used for realigning stack.  */
 291   rtx drap_reg;
 292
 293   /* Offset to end of allocated area of stack frame.
 294      If stack grows down, this is the address of the last stack slot allocated.
 295      If stack grows up, this is the address for the next slot.  */
 296   HOST_WIDE_INT x_frame_offset;
 297
 298   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
 299   rtx x_parm_birth_insn;
 300
 301   /* List of all used temporaries allocated, by level.  */
 302   VEC(temp_slot_p,gc) *x_used_temp_slots;
 303
 304   /* List of available temp slots.  */
 305   struct temp_slot *x_avail_temp_slots;
 306
 307   /* Current nesting level for temporaries.  */
 308   int x_temp_slot_level;
 309
 310   /* The largest alignment needed on the stack, including requirement
 311      for outgoing stack alignment.  */
 312   unsigned int stack_alignment_needed;
 313
 314   /* Preferred alignment of the end of stack frame, which is preferred
 315      to call other functions.  */
 316   unsigned int preferred_stack_boundary;
 317
 318   /* The minimum alignment of parameter stack.  */
 319   unsigned int parm_stack_boundary;
 320
 321   /* The largest alignment of slot allocated on the stack.  */
 322   unsigned int max_used_stack_slot_alignment;
 323
 324   /* The stack alignment estimated before reload, with consideration of
 325      following factors:
 326      1. Alignment of local stack variables (max_used_stack_slot_alignment)
 327      2. Alignment requirement to call other functions
 328         (preferred_stack_boundary)
 329      3. Alignment of non-local stack variables but might be spilled in
 330         local stack.  */
 331   unsigned int stack_alignment_estimated;
 332
 333   /* For reorg.  */
 334
 335   /* If some insns can be deferred to the delay slots of the epilogue, the
 336      delay list for them is recorded here.  */
 337   rtx epilogue_delay_list;
 338
 339   /* Nonzero if function being compiled called builtin_return_addr or
 340      builtin_frame_address with nonzero count.  */
 341   bool accesses_prior_frames;
 342
 343   /* Nonzero if the function calls __builtin_eh_return.  */
 344   bool calls_eh_return;
 345
 346   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
 347      label that can reach the exit block via non-exceptional paths. */
 348   bool saves_all_registers;
 349
 350   /* Nonzero if function being compiled has nonlocal gotos to parent
 351      function.  */
 352   bool has_nonlocal_goto;
 353
 354   /* Nonzero if function being compiled has an asm statement.  */
 355   bool has_asm_statement;
 356
 357   /* This bit is used by the exception handling logic.  It is set if all
 358      calls (if any) are sibling calls.  Such functions do not have to
 359      have EH tables generated, as they cannot throw.  A call to such a
 360      function, however, should be treated as throwing if any of its callees
 361      can throw.  */
 362   bool all_throwers_are_sibcalls;
 363
 364   /* Nonzero if stack limit checking should be enabled in the current
 365      function.  */
 366   bool limit_stack;
 367
 368   /* Nonzero if profiling code should be generated.  */
 369   bool profile;
 370
 371   /* Nonzero if the current function uses the constant pool.  */
 372   bool uses_const_pool;
 373
 374   /* Nonzero if the current function uses pic_offset_table_rtx.  */
 375   bool uses_pic_offset_table;
 376
 377   /* Nonzero if the current function needs an lsda for exception handling.  */
 378   bool uses_eh_lsda;
 379
 380   /* Set when the tail call has been produced.  */
 381   bool tail_call_emit;
 382
 383   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
 384   bool arg_pointer_save_area_init;
 385
 386   /* Nonzero if current function must be given a frame pointer.
 387      Set in global.c if anything is allocated on the stack there.  */
 388   bool frame_pointer_needed;
 389
 390   /* When set, expand should optimize for speed.  */
 391   bool maybe_hot_insn_p;
 392
 393   /* Nonzero if function stack realignment is needed.  This flag may be
 394      set twice: before and after reload.  It is set before reload wrt
 395      stack alignment estimation before reload.  It will be changed after
 396      reload if by then criteria of stack realignment is different.
 397      The value set after reload is the accurate one and is finalized.  */
 398   bool stack_realign_needed;
 399
 400   /* Nonzero if function stack realignment is tried.  This flag is set
 401      only once before reload.  It affects register elimination.  This
 402      is used to generate DWARF debug info for stack variables.  */
 403   bool stack_realign_tried;
 404
 405   /* Nonzero if function being compiled needs dynamic realigned
 406      argument pointer (drap) if stack needs realigning.  */
 407   bool need_drap;
 408
 409   /* Nonzero if function stack realignment estimation is done, namely
 410      stack_realign_needed flag has been set before reload wrt estimated
 411      stack alignment info.  */
 412   bool stack_realign_processed;
 413
 414   /* Nonzero if function stack realignment has been finalized, namely
 415      stack_realign_needed flag has been set and finalized after reload.  */
 416   bool stack_realign_finalized;
 417
 418   /* True if dbr_schedule has already been called for this function.  */
 419   bool dbr_scheduled_p;
 420
 421   /* True if current function can not throw.  Unlike
 422      TREE_NOTHROW (current_function_decl) it is set even for overwritable
 423      function where currently compiled version of it is nothrow.  */
 424   bool nothrow;
 425 };
 426
 427 #define return_label (crtl->x_return_label)
 428 #define naked_return_label (crtl->x_naked_return_label)
 429 #define stack_slot_list (crtl->x_stack_slot_list)
 430 #define parm_birth_insn (crtl->x_parm_birth_insn)
 431 #define frame_offset (crtl->x_frame_offset)
 432 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
 433 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
 434 #define used_temp_slots (crtl->x_used_temp_slots)
 435 #define avail_temp_slots (crtl->x_avail_temp_slots)
 436 #define temp_slot_level (crtl->x_temp_slot_level)
 437 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
 438 #define frame_pointer_needed (crtl->frame_pointer_needed)
 439 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
 440 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
 441
 442 extern GTY(()) struct rtl_data x_rtl;
 443
 444 /* Accessor to RTL datastructures.  We keep them statically allocated now since
 445    we never keep multiple functions.  For threaded compiler we might however
 446    want to do differently.  */
 447 #define crtl (&x_rtl)
 448
 449 /* This structure can save all the important global and static variables
 450    describing the status of the current function.  */
 451
 452 struct GTY(()) function {
 453   struct eh_status *eh;
 454
 455   /* The control flow graph for this function.  */
 456   struct control_flow_graph *cfg;
 457
 458   /* GIMPLE body for this function.  */
 459   struct gimple_seq_d *gimple_body;
 460
 461   /* SSA and dataflow information.  */
 462   struct gimple_df *gimple_df;
 463
 464   /* The loops in this function.  */
 465   struct loops *x_current_loops;
 466
 467   /* Value histograms attached to particular statements.  */
 468   htab_t GTY((skip)) value_histograms;
 469
 470   /* For function.c.  */
 471
 472   /* Points to the FUNCTION_DECL of this function.  */
 473   tree decl;
 474
 475   /* A PARM_DECL that should contain the static chain for this function.
 476      It will be initialized at the beginning of the function.  */
 477   tree static_chain_decl;
 478
 479   /* An expression that contains the non-local goto save area.  The first
 480      word is the saved frame pointer and the second is the saved stack
 481      pointer.  */
 482   tree nonlocal_goto_save_area;
 483
 484   /* List of function local variables, functions, types and constants.  */
 485   tree local_decls;
 486
 487   /* For md files.  */
 488
 489   /* tm.h can use this to store whatever it likes.  */
 490   struct machine_function * GTY ((maybe_undef)) machine;
 491
 492   /* Language-specific code can use this to store whatever it likes.  */
 493   struct language_function * language;
 494
 495   /* Used types hash table.  */
 496   htab_t GTY ((param_is (union tree_node))) used_types_hash;
 497
 498   /* Last statement uid.  */
 499   int last_stmt_uid;
 500
 501   /* Function sequence number for profiling, debugging, etc.  */
 502   int funcdef_no;
 503
 504   /* Line number of the start of the function for debugging purposes.  */
 505   location_t function_start_locus;
 506
 507   /* Line number of the end of the function.  */
 508   location_t function_end_locus;
 509
 510   /* Properties used by the pass manager.  */
 511   unsigned int curr_properties;
 512   unsigned int last_verified;
 513
 514   /* Non-null if the function does something that would prevent it from
 515      being copied; this applies to both versioning and inlining.  Set to
 516      a string describing the reason for failure.  */
 517   const char * GTY((skip)) cannot_be_copied_reason;
 518
 519   /* Collected bit flags.  */
 520
 521   /* Number of units of general registers that need saving in stdarg
 522      function.  What unit is depends on the backend, either it is number
 523      of bytes, or it can be number of registers.  */
 524   unsigned int va_list_gpr_size : 8;
 525
 526   /* Number of units of floating point registers that need saving in stdarg
 527      function.  */
 528   unsigned int va_list_fpr_size : 8;
 529
 530   /* Nonzero if function being compiled can call setjmp.  */
 531   unsigned int calls_setjmp : 1;
 532
 533   /* Nonzero if function being compiled can call alloca,
 534      either as a subroutine or builtin.  */
 535   unsigned int calls_alloca : 1;
 536
 537   /* Nonzero if function being compiled receives nonlocal gotos
 538      from nested functions.  */
 539   unsigned int has_nonlocal_label : 1;
 540
 541   /* Nonzero if we've set cannot_be_copied_reason.  I.e. if
 542      (cannot_be_copied_set && !cannot_be_copied_reason), the function
 543      can in fact be copied.  */
 544   unsigned int cannot_be_copied_set : 1;
 545
 546   /* Nonzero if current function uses stdarg.h or equivalent.  */
 547   unsigned int stdarg : 1;
 548
 549   /* Nonzero if the back-end should not keep track of expressions that
 550      determine the size of variable-sized objects.  Normally, such
 551      expressions are saved away, and then expanded when the next
 552      function is started.  For example, if a parameter has a
 553      variable-sized type, then the size of the parameter is computed
 554      when the function body is entered.  However, some front-ends do
 555      not desire this behavior.  */
 556   unsigned int dont_save_pending_sizes_p : 1;
 557
 558   unsigned int after_inlining : 1;
 559   unsigned int always_inline_functions_inlined : 1;
 560
 561   /* Fields below this point are not set for abstract functions; see
 562      allocate_struct_function.  */
 563
 564   /* Nonzero if function being compiled needs to be given an address
 565      where the value should be stored.  */
 566   unsigned int returns_struct : 1;
 567
 568   /* Nonzero if function being compiled needs to
 569      return the address of where it has put a structure value.  */
 570   unsigned int returns_pcc_struct : 1;
 571
 572   /* Nonzero if pass_tree_profile was run on this function.  */
 573   unsigned int after_tree_profile : 1;
 574
 575   /* Nonzero if this function has local DECL_HARD_REGISTER variables.
 576      In this case code motion has to be done more carefully.  */
 577   unsigned int has_local_explicit_reg_vars : 1;
 578
 579   /* Nonzero if the current function is a thunk, i.e., a lightweight
 580      function implemented by the output_mi_thunk hook) that just
 581      adjusts one of its arguments and forwards to another
 582      function.  */
 583   unsigned int is_thunk : 1;
 584 };
 585
 586 /* If va_list_[gf]pr_size is set to this, it means we don't know how
 587    many units need to be saved.  */
 588 #define VA_LIST_MAX_GPR_SIZE    255
 589 #define VA_LIST_MAX_FPR_SIZE    255
 590
 591 /* The function currently being compiled.  */
 592 extern GTY(()) struct function *cfun;
 593
 594 /* In order to ensure that cfun is not set directly, we redefine it so
 595    that it is not an lvalue.  Rather than assign to cfun, use
 596    push_cfun or set_cfun.  */
 597 #define cfun (cfun + 0)
 598
 599 /* Nonzero if we've already converted virtual regs to hard regs.  */
 600 extern int virtuals_instantiated;
 601
 602 /* Nonzero if at least one trampoline has been created.  */
 603 extern int trampolines_created;
 604
 605 struct GTY(()) types_used_by_vars_entry {
 606   tree type;
 607   tree var_decl;
 608 };
 609
 610 /* Hash table making the relationship between a global variable
 611    and the types it references in its initializer. The key of the
 612    entry is a referenced type, and the value is the DECL of the global
 613    variable. types_use_by_vars_do_hash and types_used_by_vars_eq below are
 614    the hash and equality functions to use for this hash table.  */
 615 extern GTY((param_is (struct types_used_by_vars_entry))) htab_t
 616   types_used_by_vars_hash;
 617
 618 hashval_t types_used_by_vars_do_hash (const void*);
 619 int types_used_by_vars_eq (const void *, const void *);
 620 void types_used_by_var_decl_insert (tree type, tree var_decl);
 621
 622 /* During parsing of a global variable, this linked list points to
 623    the list of types referenced by the global variable.  */
 624 extern GTY(()) tree types_used_by_cur_var_decl;
 625
 626
 627 /* cfun shouldn't be set directly; use one of these functions instead.  */
 628 extern void set_cfun (struct function *new_cfun);
 629 extern void push_cfun (struct function *new_cfun);
 630 extern void pop_cfun (void);
 631 extern void instantiate_decl_rtl (rtx x);
 632
 633 /* For backward compatibility... eventually these should all go away.  */
 634 #define current_function_funcdef_no (cfun->funcdef_no)
 635
 636 #define current_loops (cfun->x_current_loops)
 637 #define dom_computed (cfun->cfg->x_dom_computed)
 638 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
 639 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
 640
 641 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
 642    and create duplicate blocks.  */
 643 extern void reorder_blocks (void);
 644
 645 /* Set BLOCK_NUMBER for all the blocks in FN.  */
 646 extern void number_blocks (tree);
 647
 648 extern void clear_block_marks (tree);
 649 extern tree blocks_nreverse (tree);
 650
 651 /* Return size needed for stack frame based on slots so far allocated.
 652    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
 653    the caller may have to do that.  */
 654 extern HOST_WIDE_INT get_frame_size (void);
 655
 656 /* Issue an error message and return TRUE if frame OFFSET overflows in
 657    the signed target pointer arithmetics for function FUNC.  Otherwise
 658    return FALSE.  */
 659 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
 660
 661 /* A pointer to a function to create target specific, per-function
 662    data structures.  */
 663 extern struct machine_function * (*init_machine_status) (void);
 664
 665 /* Save and restore status information for a nested function.  */
 666 extern void free_after_parsing (struct function *);
 667 extern void free_after_compilation (struct function *);
 668
 669 extern void init_varasm_status (void);
 670
 671 #ifdef RTX_CODE
 672 extern void diddle_return_value (void (*)(rtx, void*), void*);
 673 extern void clobber_return_register (void);
 674 #endif
 675
 676 extern rtx get_arg_pointer_save_area (void);
 677
 678 /* Returns the name of the current function.  */
 679 extern const char *current_function_name (void);
 680
 681 extern void do_warn_unused_parameter (tree);
 682
 683 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
 684                                tree, bool);
 685 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
 686                                      tree, bool);
 687
 688 extern void used_types_insert (tree);
 689
 690 extern int get_next_funcdef_no (void);
 691 #endif  /* GCC_FUNCTION_H */