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      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 {
     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   /* 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;
     78 
     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;
     83 };
     84 
     85 
     86 /* Indexed by register number, gives an rtx for that register (and only
     87    that register).  For pseudo registers, it is the unique rtx for
     88    that pseudo.  For hard registers, it is an rtx of the mode specified
     89    by reg_raw_mode.
     90 
     91    FIXME: We could put it into emit_status struct, but gengtype is not
     92    able to deal with length attribute nested in top level structures.  */
     93 
     94 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx * regno_reg_rtx;
     95 
     96 /* For backward compatibility... eventually these should all go away.  */
     97 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
     98 #define seq_stack (crtl->emit.sequence_stack)
     99 
    100 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
    101 
    102 struct GTY(()) expr_status {
    103   /* Number of units that we should eventually pop off the stack.
    104      These are the arguments to function calls that have already returned.  */
    105   int x_pending_stack_adjust;
    106 
    107   /* Under some ABIs, it is the caller's responsibility to pop arguments
    108      pushed for function calls.  A naive implementation would simply pop
    109      the arguments immediately after each call.  However, if several
    110      function calls are made in a row, it is typically cheaper to pop
    111      all the arguments after all of the calls are complete since a
    112      single pop instruction can be used.  Therefore, GCC attempts to
    113      defer popping the arguments until absolutely necessary.  (For
    114      example, at the end of a conditional, the arguments must be popped,
    115      since code outside the conditional won't know whether or not the
    116      arguments need to be popped.)
    117 
    118      When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
    119      attempt to defer pops.  Instead, the stack is popped immediately
    120      after each call.  Rather then setting this variable directly, use
    121      NO_DEFER_POP and OK_DEFER_POP.  */
    122   int x_inhibit_defer_pop;
    123 
    124   /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
    125      boundary can be momentarily unaligned while pushing the arguments.
    126      Record the delta since last aligned boundary here in order to get
    127      stack alignment in the nested function calls working right.  */
    128   int x_stack_pointer_delta;
    129 
    130   /* Nonzero means __builtin_saveregs has already been done in this function.
    131      The value is the pseudoreg containing the value __builtin_saveregs
    132      returned.  */
    133   rtx x_saveregs_value;
    134 
    135   /* Similarly for __builtin_apply_args.  */
    136   rtx x_apply_args_value;
    137 
    138   /* List of labels that must never be deleted.  */
    139   rtx x_forced_labels;
    140 };
    141 
    142 typedef struct call_site_record_d *call_site_record;
    143 
    144 /* RTL representation of exception handling.  */
    145 struct GTY(()) rtl_eh {
    146   rtx ehr_stackadj;
    147   rtx ehr_handler;
    148   rtx ehr_label;
    149 
    150   rtx sjlj_fc;
    151   rtx sjlj_exit_after;
    152 
    153   vec<uchar, va_gc> *action_record_data;
    154 
    155   vec<call_site_record, va_gc> *call_site_record_v[2];
    156 };
    157 
    158 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
    159 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
    160 #define saveregs_value (crtl->expr.x_saveregs_value)
    161 #define apply_args_value (crtl->expr.x_apply_args_value)
    162 #define forced_labels (crtl->expr.x_forced_labels)
    163 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
    164 
    165 struct gimple_df;
    166 struct temp_slot;
    167 typedef struct temp_slot *temp_slot_p;
    168 struct call_site_record_d;
    169 struct dw_fde_struct;
    170 
    171 struct ipa_opt_pass_d;
    172 typedef struct ipa_opt_pass_d *ipa_opt_pass;
    173 
    174 
    175 struct GTY(()) varasm_status {
    176   /* If we're using a per-function constant pool, this is it.  */
    177   struct rtx_constant_pool *pool;
    178 
    179   /* Number of tree-constants deferred during the expansion of this
    180      function.  */
    181   unsigned int deferred_constants;
    182 };
    183 
    184 /* Information mainlined about RTL representation of incoming arguments.  */
    185 struct GTY(()) incoming_args {
    186   /* Number of bytes of args popped by function being compiled on its return.
    187      Zero if no bytes are to be popped.
    188      May affect compilation of return insn or of function epilogue.  */
    189   int pops_args;
    190 
    191   /* If function's args have a fixed size, this is that size, in bytes.
    192      Otherwise, it is -1.
    193      May affect compilation of return insn or of function epilogue.  */
    194   int size;
    195 
    196   /* # bytes the prologue should push and pretend that the caller pushed them.
    197      The prologue must do this, but only if parms can be passed in
    198      registers.  */
    199   int pretend_args_size;
    200 
    201   /* This is the offset from the arg pointer to the place where the first
    202      anonymous arg can be found, if there is one.  */
    203   rtx arg_offset_rtx;
    204 
    205   /* Quantities of various kinds of registers
    206      used for the current function's args.  */
    207   CUMULATIVE_ARGS info;
    208 
    209   /* The arg pointer hard register, or the pseudo into which it was copied.  */
    210   rtx internal_arg_pointer;
    211 };
    212 
    213 /* Data for function partitioning.  */
    214 struct GTY(()) function_subsections {
    215   /* Assembly labels for the hot and cold text sections, to
    216      be used by debugger functions for determining the size of text
    217      sections.  */
    218 
    219   const char *hot_section_label;
    220   const char *cold_section_label;
    221   const char *hot_section_end_label;
    222   const char *cold_section_end_label;
    223 };
    224 
    225 /* Describe an empty area of space in the stack frame.  These can be chained
    226    into a list; this is used to keep track of space wasted for alignment
    227    reasons.  */
    228 struct GTY(()) frame_space
    229 {
    230   struct frame_space *next;
    231 
    232   HOST_WIDE_INT start;
    233   HOST_WIDE_INT length;
    234 };
    235 
    236 /* Datastructures maintained for currently processed function in RTL form.  */
    237 struct GTY(()) rtl_data {
    238   struct expr_status expr;
    239   struct emit_status emit;
    240   struct varasm_status varasm;
    241   struct incoming_args args;
    242   struct function_subsections subsections;
    243   struct rtl_eh eh;
    244 
    245   /* For function.c  */
    246 
    247   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
    248      defined, the needed space is pushed by the prologue.  */
    249   int outgoing_args_size;
    250 
    251   /* If nonzero, an RTL expression for the location at which the current
    252      function returns its result.  If the current function returns its
    253      result in a register, current_function_return_rtx will always be
    254      the hard register containing the result.  */
    255   rtx return_rtx;
    256 
    257   /* Vector of initial-value pairs.  Each pair consists of a pseudo
    258      register of approprite mode that stores the initial value a hard
    259      register REGNO, and that hard register itself.  */
    260   /* ??? This could be a VEC but there is currently no way to define an
    261 	 opaque VEC type.  */
    262   struct initial_value_struct *hard_reg_initial_vals;
    263 
    264   /* A variable living at the top of the frame that holds a known value.
    265      Used for detecting stack clobbers.  */
    266   tree stack_protect_guard;
    267 
    268   /* List (chain of EXPR_LIST) of labels heading the current handlers for
    269      nonlocal gotos.  */
    270   rtx x_nonlocal_goto_handler_labels;
    271 
    272   /* Label that will go on function epilogue.
    273      Jumping to this label serves as a "return" instruction
    274      on machines which require execution of the epilogue on all returns.  */
    275   rtx x_return_label;
    276 
    277   /* Label that will go on the end of function epilogue.
    278      Jumping to this label serves as a "naked return" instruction
    279      on machines which require execution of the epilogue on all returns.  */
    280   rtx x_naked_return_label;
    281 
    282   /* List (chain of EXPR_LISTs) of all stack slots in this function.
    283      Made for the sake of unshare_all_rtl.  */
    284   rtx x_stack_slot_list;
    285 
    286   /* List of empty areas in the stack frame.  */
    287   struct frame_space *frame_space_list;
    288 
    289   /* Place after which to insert the tail_recursion_label if we need one.  */
    290   rtx x_stack_check_probe_note;
    291 
    292   /* Location at which to save the argument pointer if it will need to be
    293      referenced.  There are two cases where this is done: if nonlocal gotos
    294      exist, or if vars stored at an offset from the argument pointer will be
    295      needed by inner routines.  */
    296   rtx x_arg_pointer_save_area;
    297 
    298   /* Dynamic Realign Argument Pointer used for realigning stack.  */
    299   rtx drap_reg;
    300 
    301   /* Offset to end of allocated area of stack frame.
    302      If stack grows down, this is the address of the last stack slot allocated.
    303      If stack grows up, this is the address for the next slot.  */
    304   HOST_WIDE_INT x_frame_offset;
    305 
    306   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
    307   rtx x_parm_birth_insn;
    308 
    309   /* List of all used temporaries allocated, by level.  */
    310   vec<temp_slot_p, va_gc> *x_used_temp_slots;
    311 
    312   /* List of available temp slots.  */
    313   struct temp_slot *x_avail_temp_slots;
    314 
    315   /* Current nesting level for temporaries.  */
    316   int x_temp_slot_level;
    317 
    318   /* The largest alignment needed on the stack, including requirement
    319      for outgoing stack alignment.  */
    320   unsigned int stack_alignment_needed;
    321 
    322   /* Preferred alignment of the end of stack frame, which is preferred
    323      to call other functions.  */
    324   unsigned int preferred_stack_boundary;
    325 
    326   /* The minimum alignment of parameter stack.  */
    327   unsigned int parm_stack_boundary;
    328 
    329   /* The largest alignment of slot allocated on the stack.  */
    330   unsigned int max_used_stack_slot_alignment;
    331 
    332   /* The stack alignment estimated before reload, with consideration of
    333      following factors:
    334      1. Alignment of local stack variables (max_used_stack_slot_alignment)
    335      2. Alignment requirement to call other functions
    336         (preferred_stack_boundary)
    337      3. Alignment of non-local stack variables but might be spilled in
    338         local stack.  */
    339   unsigned int stack_alignment_estimated;
    340 
    341   /* For reorg.  */
    342 
    343   /* Nonzero if function being compiled called builtin_return_addr or
    344      builtin_frame_address with nonzero count.  */
    345   bool accesses_prior_frames;
    346 
    347   /* Nonzero if the function calls __builtin_eh_return.  */
    348   bool calls_eh_return;
    349 
    350   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
    351      label that can reach the exit block via non-exceptional paths. */
    352   bool saves_all_registers;
    353 
    354   /* Nonzero if function being compiled has nonlocal gotos to parent
    355      function.  */
    356   bool has_nonlocal_goto;
    357 
    358   /* Nonzero if function being compiled has an asm statement.  */
    359   bool has_asm_statement;
    360 
    361   /* This bit is used by the exception handling logic.  It is set if all
    362      calls (if any) are sibling calls.  Such functions do not have to
    363      have EH tables generated, as they cannot throw.  A call to such a
    364      function, however, should be treated as throwing if any of its callees
    365      can throw.  */
    366   bool all_throwers_are_sibcalls;
    367 
    368   /* Nonzero if stack limit checking should be enabled in the current
    369      function.  */
    370   bool limit_stack;
    371 
    372   /* Nonzero if profiling code should be generated.  */
    373   bool profile;
    374 
    375   /* Nonzero if the current function uses the constant pool.  */
    376   bool uses_const_pool;
    377 
    378   /* Nonzero if the current function uses pic_offset_table_rtx.  */
    379   bool uses_pic_offset_table;
    380 
    381   /* Nonzero if the current function needs an lsda for exception handling.  */
    382   bool uses_eh_lsda;
    383 
    384   /* Set when the tail call has been produced.  */
    385   bool tail_call_emit;
    386 
    387   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
    388   bool arg_pointer_save_area_init;
    389 
    390   /* Nonzero if current function must be given a frame pointer.
    391      Set in reload1.c or lra-eliminations.c if anything is allocated
    392      on the stack there.  */
    393   bool frame_pointer_needed;
    394 
    395   /* When set, expand should optimize for speed.  */
    396   bool maybe_hot_insn_p;
    397 
    398   /* Nonzero if function stack realignment is needed.  This flag may be
    399      set twice: before and after reload.  It is set before reload wrt
    400      stack alignment estimation before reload.  It will be changed after
    401      reload if by then criteria of stack realignment is different.
    402      The value set after reload is the accurate one and is finalized.  */
    403   bool stack_realign_needed;
    404 
    405   /* Nonzero if function stack realignment is tried.  This flag is set
    406      only once before reload.  It affects register elimination.  This
    407      is used to generate DWARF debug info for stack variables.  */
    408   bool stack_realign_tried;
    409 
    410   /* Nonzero if function being compiled needs dynamic realigned
    411      argument pointer (drap) if stack needs realigning.  */
    412   bool need_drap;
    413 
    414   /* Nonzero if function stack realignment estimation is done, namely
    415      stack_realign_needed flag has been set before reload wrt estimated
    416      stack alignment info.  */
    417   bool stack_realign_processed;
    418 
    419   /* Nonzero if function stack realignment has been finalized, namely
    420      stack_realign_needed flag has been set and finalized after reload.  */
    421   bool stack_realign_finalized;
    422 
    423   /* True if dbr_schedule has already been called for this function.  */
    424   bool dbr_scheduled_p;
    425 
    426   /* True if current function can not throw.  Unlike
    427      TREE_NOTHROW (current_function_decl) it is set even for overwritable
    428      function where currently compiled version of it is nothrow.  */
    429   bool nothrow;
    430 
    431   /* True if we performed shrink-wrapping for the current function.  */
    432   bool shrink_wrapped;
    433 
    434   /* Nonzero if function being compiled doesn't modify the stack pointer
    435      (ignoring the prologue and epilogue).  This is only valid after
    436      pass_stack_ptr_mod has run.  */
    437   bool sp_is_unchanging;
    438 
    439   /* Nonzero if function being compiled doesn't contain any calls
    440      (ignoring the prologue and epilogue).  This is set prior to
    441      local register allocation and is valid for the remaining
    442      compiler passes.  */
    443   bool is_leaf;
    444 
    445   /* Nonzero if the function being compiled is a leaf function which only
    446      uses leaf registers.  This is valid after reload (specifically after
    447      sched2) and is useful only if the port defines LEAF_REGISTERS.  */
    448   bool uses_only_leaf_regs;
    449 
    450   /* Like regs_ever_live, but 1 if a reg is set or clobbered from an
    451      asm.  Unlike regs_ever_live, elements of this array corresponding
    452      to eliminable regs (like the frame pointer) are set if an asm
    453      sets them.  */
    454   HARD_REG_SET asm_clobbers;
    455 };
    456 
    457 #define return_label (crtl->x_return_label)
    458 #define naked_return_label (crtl->x_naked_return_label)
    459 #define stack_slot_list (crtl->x_stack_slot_list)
    460 #define parm_birth_insn (crtl->x_parm_birth_insn)
    461 #define frame_offset (crtl->x_frame_offset)
    462 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
    463 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
    464 #define used_temp_slots (crtl->x_used_temp_slots)
    465 #define avail_temp_slots (crtl->x_avail_temp_slots)
    466 #define temp_slot_level (crtl->x_temp_slot_level)
    467 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
    468 #define frame_pointer_needed (crtl->frame_pointer_needed)
    469 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
    470 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
    471 
    472 extern GTY(()) struct rtl_data x_rtl;
    473 
    474 /* Accessor to RTL datastructures.  We keep them statically allocated now since
    475    we never keep multiple functions.  For threaded compiler we might however
    476    want to do differently.  */
    477 #define crtl (&x_rtl)
    478 
    479 struct GTY(()) stack_usage
    480 {
    481   /* # of bytes of static stack space allocated by the function.  */
    482   HOST_WIDE_INT static_stack_size;
    483 
    484   /* # of bytes of dynamic stack space allocated by the function.  This is
    485      meaningful only if has_unbounded_dynamic_stack_size is zero.  */
    486   HOST_WIDE_INT dynamic_stack_size;
    487 
    488   /* # of bytes of space pushed onto the stack after the prologue.  If
    489      !ACCUMULATE_OUTGOING_ARGS, it contains the outgoing arguments.  */
    490   int pushed_stack_size;
    491 
    492   /* Nonzero if the amount of stack space allocated dynamically cannot
    493      be bounded at compile-time.  */
    494   unsigned int has_unbounded_dynamic_stack_size : 1;
    495 };
    496 
    497 #define current_function_static_stack_size (cfun->su->static_stack_size)
    498 #define current_function_dynamic_stack_size (cfun->su->dynamic_stack_size)
    499 #define current_function_pushed_stack_size (cfun->su->pushed_stack_size)
    500 #define current_function_has_unbounded_dynamic_stack_size \
    501   (cfun->su->has_unbounded_dynamic_stack_size)
    502 #define current_function_allocates_dynamic_stack_space    \
    503   (current_function_dynamic_stack_size != 0               \
    504    || current_function_has_unbounded_dynamic_stack_size)
    505 
    506 /* This structure can save all the important global and static variables
    507    describing the status of the current function.  */
    508 
    509 struct GTY(()) function {
    510   struct eh_status *eh;
    511 
    512   /* The control flow graph for this function.  */
    513   struct control_flow_graph *cfg;
    514 
    515   /* GIMPLE body for this function.  */
    516   gimple_seq gimple_body;
    517 
    518   /* SSA and dataflow information.  */
    519   struct gimple_df *gimple_df;
    520 
    521   /* The loops in this function.  */
    522   struct loops *x_current_loops;
    523 
    524   /* The stack usage of this function.  */
    525   struct stack_usage *su;
    526 
    527   /* Value histograms attached to particular statements.  */
    528   htab_t GTY((skip)) value_histograms;
    529 
    530   /* For function.c.  */
    531 
    532   /* Points to the FUNCTION_DECL of this function.  */
    533   tree decl;
    534 
    535   /* A PARM_DECL that should contain the static chain for this function.
    536      It will be initialized at the beginning of the function.  */
    537   tree static_chain_decl;
    538 
    539   /* An expression that contains the non-local goto save area.  The first
    540      word is the saved frame pointer and the second is the saved stack
    541      pointer.  */
    542   tree nonlocal_goto_save_area;
    543 
    544   /* Vector of function local variables, functions, types and constants.  */
    545   vec<tree, va_gc> *local_decls;
    546 
    547   /* For md files.  */
    548 
    549   /* tm.h can use this to store whatever it likes.  */
    550   struct machine_function * GTY ((maybe_undef)) machine;
    551 
    552   /* Language-specific code can use this to store whatever it likes.  */
    553   struct language_function * language;
    554 
    555   /* Used types hash table.  */
    556   htab_t GTY ((param_is (union tree_node))) used_types_hash;
    557 
    558   /* Dwarf2 Frame Description Entry, containing the Call Frame Instructions
    559      used for unwinding.  Only set when either dwarf2 unwinding or dwarf2
    560      debugging is enabled.  */
    561   struct dw_fde_struct *fde;
    562 
    563   /* Last statement uid.  */
    564   int last_stmt_uid;
    565 
    566   /* Function sequence number for profiling, debugging, etc.  */
    567   int funcdef_no;
    568 
    569   /* Line number of the start of the function for debugging purposes.  */
    570   location_t function_start_locus;
    571 
    572   /* Line number of the end of the function.  */
    573   location_t function_end_locus;
    574 
    575   /* Properties used by the pass manager.  */
    576   unsigned int curr_properties;
    577   unsigned int last_verified;
    578 
    579   /* Non-null if the function does something that would prevent it from
    580      being copied; this applies to both versioning and inlining.  Set to
    581      a string describing the reason for failure.  */
    582   const char * GTY((skip)) cannot_be_copied_reason;
    583 
    584   /* Collected bit flags.  */
    585 
    586   /* Number of units of general registers that need saving in stdarg
    587      function.  What unit is depends on the backend, either it is number
    588      of bytes, or it can be number of registers.  */
    589   unsigned int va_list_gpr_size : 8;
    590 
    591   /* Number of units of floating point registers that need saving in stdarg
    592      function.  */
    593   unsigned int va_list_fpr_size : 8;
    594 
    595   /* Nonzero if function being compiled can call setjmp.  */
    596   unsigned int calls_setjmp : 1;
    597 
    598   /* Nonzero if function being compiled can call alloca,
    599      either as a subroutine or builtin.  */
    600   unsigned int calls_alloca : 1;
    601 
    602   /* Nonzero if function being compiled receives nonlocal gotos
    603      from nested functions.  */
    604   unsigned int has_nonlocal_label : 1;
    605 
    606   /* Nonzero if we've set cannot_be_copied_reason.  I.e. if
    607      (cannot_be_copied_set && !cannot_be_copied_reason), the function
    608      can in fact be copied.  */
    609   unsigned int cannot_be_copied_set : 1;
    610 
    611   /* Nonzero if current function uses stdarg.h or equivalent.  */
    612   unsigned int stdarg : 1;
    613 
    614   unsigned int after_inlining : 1;
    615   unsigned int always_inline_functions_inlined : 1;
    616 
    617   /* Nonzero if function being compiled can throw synchronous non-call
    618      exceptions.  */
    619   unsigned int can_throw_non_call_exceptions : 1;
    620 
    621   /* Nonzero if instructions that may throw exceptions but don't otherwise
    622      contribute to the execution of the program can be deleted.  */
    623   unsigned int can_delete_dead_exceptions : 1;
    624 
    625   /* Fields below this point are not set for abstract functions; see
    626      allocate_struct_function.  */
    627 
    628   /* Nonzero if function being compiled needs to be given an address
    629      where the value should be stored.  */
    630   unsigned int returns_struct : 1;
    631 
    632   /* Nonzero if function being compiled needs to
    633      return the address of where it has put a structure value.  */
    634   unsigned int returns_pcc_struct : 1;
    635 
    636   /* Nonzero if this function has local DECL_HARD_REGISTER variables.
    637      In this case code motion has to be done more carefully.  */
    638   unsigned int has_local_explicit_reg_vars : 1;
    639 
    640   /* Nonzero if the current function is a thunk, i.e., a lightweight
    641      function implemented by the output_mi_thunk hook) that just
    642      adjusts one of its arguments and forwards to another
    643      function.  */
    644   unsigned int is_thunk : 1;
    645 };
    646 
    647 /* Add the decl D to the local_decls list of FUN.  */
    648 
    649 static inline void
    650 add_local_decl (struct function *fun, tree d)
    651 {
    652   vec_safe_push (fun->local_decls, d);
    653 }
    654 
    655 #define FOR_EACH_LOCAL_DECL(FUN, I, D)		\
    656   FOR_EACH_VEC_SAFE_ELT_REVERSE ((FUN)->local_decls, I, D)
    657 
    658 /* If va_list_[gf]pr_size is set to this, it means we don't know how
    659    many units need to be saved.  */
    660 #define VA_LIST_MAX_GPR_SIZE	255
    661 #define VA_LIST_MAX_FPR_SIZE	255
    662 
    663 /* The function currently being compiled.  */
    664 extern GTY(()) struct function *cfun;
    665 
    666 /* In order to ensure that cfun is not set directly, we redefine it so
    667    that it is not an lvalue.  Rather than assign to cfun, use
    668    push_cfun or set_cfun.  */
    669 #define cfun (cfun + 0)
    670 
    671 /* Nonzero if we've already converted virtual regs to hard regs.  */
    672 extern int virtuals_instantiated;
    673 
    674 /* Nonzero if at least one trampoline has been created.  */
    675 extern int trampolines_created;
    676 
    677 struct GTY(()) types_used_by_vars_entry {
    678   tree type;
    679   tree var_decl;
    680 };
    681 
    682 /* Hash table making the relationship between a global variable
    683    and the types it references in its initializer. The key of the
    684    entry is a referenced type, and the value is the DECL of the global
    685    variable. types_use_by_vars_do_hash and types_used_by_vars_eq below are
    686    the hash and equality functions to use for this hash table.  */
    687 extern GTY((param_is (struct types_used_by_vars_entry))) htab_t
    688   types_used_by_vars_hash;
    689 
    690 hashval_t types_used_by_vars_do_hash (const void*);
    691 int types_used_by_vars_eq (const void *, const void *);
    692 void types_used_by_var_decl_insert (tree type, tree var_decl);
    693 
    694 /* During parsing of a global variable, this vector contains the types
    695    referenced by the global variable.  */
    696 extern GTY(()) vec<tree, va_gc> *types_used_by_cur_var_decl;
    697 
    698 /* cfun shouldn't be set directly; use one of these functions instead.  */
    699 extern void set_cfun (struct function *new_cfun);
    700 extern void push_cfun (struct function *new_cfun);
    701 extern void pop_cfun (void);
    702 extern void instantiate_decl_rtl (rtx x);
    703 
    704 /* For backward compatibility... eventually these should all go away.  */
    705 #define current_function_funcdef_no (cfun->funcdef_no)
    706 
    707 #define current_loops (cfun->x_current_loops)
    708 #define dom_computed (cfun->cfg->x_dom_computed)
    709 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
    710 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
    711 
    712 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
    713    and create duplicate blocks.  */
    714 extern void reorder_blocks (void);
    715 
    716 /* Set BLOCK_NUMBER for all the blocks in FN.  */
    717 extern void number_blocks (tree);
    718 
    719 extern void clear_block_marks (tree);
    720 extern tree blocks_nreverse (tree);
    721 extern tree block_chainon (tree, tree);
    722 
    723 /* Return size needed for stack frame based on slots so far allocated.
    724    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
    725    the caller may have to do that.  */
    726 extern HOST_WIDE_INT get_frame_size (void);
    727 
    728 /* Issue an error message and return TRUE if frame OFFSET overflows in
    729    the signed target pointer arithmetics for function FUNC.  Otherwise
    730    return FALSE.  */
    731 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
    732 
    733 /* A pointer to a function to create target specific, per-function
    734    data structures.  */
    735 extern struct machine_function * (*init_machine_status) (void);
    736 
    737 /* Save and restore status information for a nested function.  */
    738 extern void free_after_parsing (struct function *);
    739 extern void free_after_compilation (struct function *);
    740 
    741 extern void init_varasm_status (void);
    742 
    743 #ifdef RTX_CODE
    744 extern void diddle_return_value (void (*)(rtx, void*), void*);
    745 extern void clobber_return_register (void);
    746 #endif
    747 
    748 extern rtx get_arg_pointer_save_area (void);
    749 
    750 /* Returns the name of the current function.  */
    751 extern const char *fndecl_name (tree);
    752 extern const char *function_name (struct function *);
    753 extern const char *current_function_name (void);
    754 
    755 extern void do_warn_unused_parameter (tree);
    756 
    757 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
    758 			       tree, bool);
    759 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
    760 				     tree, bool);
    761 
    762 extern void used_types_insert (tree);
    763 
    764 extern int get_next_funcdef_no (void);
    765 extern int get_last_funcdef_no (void);
    766 
    767 #ifdef HAVE_simple_return
    768 extern bool requires_stack_frame_p (rtx, HARD_REG_SET, HARD_REG_SET);
    769 #endif
    770 
    771 extern rtx get_hard_reg_initial_val (enum machine_mode, unsigned int);
    772 extern rtx has_hard_reg_initial_val (enum machine_mode, unsigned int);
    773 extern rtx get_hard_reg_initial_reg (rtx);
    774 extern bool initial_value_entry (int i, rtx *, rtx *);
    775 
    776 /* Called from gimple_expand_cfg.  */
    777 extern unsigned int emit_initial_value_sets (void);
    778 
    779 /* In predict.c */
    780 extern bool optimize_function_for_size_p (struct function *);
    781 extern bool optimize_function_for_speed_p (struct function *);
    782 
    783 #endif  /* GCC_FUNCTION_H */
    784