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      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 "varray.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 sequence_stack GTY(())
     35 {
     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 emit_status GTY(())
     44 {
     45   /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
     46      After rtl generation, it is 1 plus the largest register number used.  */
     47   int x_reg_rtx_no;
     48 
     49   /* Lowest label number in current function.  */
     50   int x_first_label_num;
     51 
     52   /* The ends of the doubly-linked chain of rtl for the current function.
     53      Both are reset to null at the start of rtl generation for the function.
     54 
     55      start_sequence saves both of these on `sequence_stack' and then starts
     56      a new, nested sequence of insns.  */
     57   rtx x_first_insn;
     58   rtx x_last_insn;
     59 
     60   /* Stack of pending (incomplete) sequences saved by `start_sequence'.
     61      Each element describes one pending sequence.
     62      The main insn-chain is saved in the last element of the chain,
     63      unless the chain is empty.  */
     64   struct sequence_stack *sequence_stack;
     65 
     66   /* INSN_UID for next insn emitted.
     67      Reset to 1 for each function compiled.  */
     68   int x_cur_insn_uid;
     69 
     70   /* Location the last line-number NOTE emitted.
     71      This is used to avoid generating duplicates.  */
     72   location_t x_last_location;
     73 
     74   /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
     75      vectors.  Since these vectors are needed during the expansion phase when
     76      the total number of registers in the function is not yet known, the
     77      vectors are copied and made bigger when necessary.  */
     78   int regno_pointer_align_length;
     79 
     80   /* Indexed by pseudo register number, if nonzero gives the known alignment
     81      for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
     82      Allocated in parallel with x_regno_reg_rtx.  */
     83   unsigned char * GTY((skip)) regno_pointer_align;
     84 };
     85 
     86 
     87 /* Indexed by pseudo register number, gives the rtx for that pseudo.
     88    Allocated in parallel with regno_pointer_align.
     89    FIXME: We could put it into emit_status struct, but gengtype is not able to deal
     90    with length attribute nested in top level structures.  */
     91 
     92 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx * regno_reg_rtx;
     93 
     94 /* For backward compatibility... eventually these should all go away.  */
     95 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
     96 #define seq_stack (crtl->emit.sequence_stack)
     97 
     98 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
     99 
    100 struct expr_status GTY(())
    101 {
    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 *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 rtl_eh GTY(())
    147 {
    148   rtx filter;
    149   rtx exc_ptr;
    150 
    151   int built_landing_pads;
    152 
    153   rtx ehr_stackadj;
    154   rtx ehr_handler;
    155   rtx ehr_label;
    156 
    157   rtx sjlj_fc;
    158   rtx sjlj_exit_after;
    159 
    160   htab_t GTY ((param_is (struct ehl_map_entry))) exception_handler_label_map;
    161 
    162   VEC(tree,gc) *ttype_data;
    163   varray_type ehspec_data;
    164   varray_type action_record_data;
    165 
    166   VEC(call_site_record,gc) *call_site_record;
    167 };
    168 
    169 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
    170 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
    171 #define saveregs_value (crtl->expr.x_saveregs_value)
    172 #define apply_args_value (crtl->expr.x_apply_args_value)
    173 #define forced_labels (crtl->expr.x_forced_labels)
    174 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
    175 
    176 struct gimple_df;
    177 struct temp_slot;
    178 typedef struct temp_slot *temp_slot_p;
    179 struct call_site_record;
    180 
    181 DEF_VEC_P(temp_slot_p);
    182 DEF_VEC_ALLOC_P(temp_slot_p,gc);
    183 struct ipa_opt_pass;
    184 typedef struct ipa_opt_pass *ipa_opt_pass;
    185 
    186 DEF_VEC_P(ipa_opt_pass);
    187 DEF_VEC_ALLOC_P(ipa_opt_pass,heap);
    188 
    189 enum function_frequency {
    190   /* This function most likely won't be executed at all.
    191      (set only when profile feedback is available or via function attribute). */
    192   FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
    193   /* The default value.  */
    194   FUNCTION_FREQUENCY_NORMAL,
    195   /* Optimize this function hard
    196      (set only when profile feedback is available or via function attribute). */
    197   FUNCTION_FREQUENCY_HOT
    198 };
    199 
    200 struct varasm_status GTY(())
    201 {
    202   /* If we're using a per-function constant pool, this is it.  */
    203   struct rtx_constant_pool *pool;
    204 
    205   /* Number of tree-constants deferred during the expansion of this
    206      function.  */
    207   unsigned int deferred_constants;
    208 };
    209 
    210 /* Information mainlined about RTL representation of incoming arguments.  */
    211 struct incoming_args GTY(())
    212 {
    213   /* Number of bytes of args popped by function being compiled on its return.
    214      Zero if no bytes are to be popped.
    215      May affect compilation of return insn or of function epilogue.  */
    216   int pops_args;
    217 
    218   /* If function's args have a fixed size, this is that size, in bytes.
    219      Otherwise, it is -1.
    220      May affect compilation of return insn or of function epilogue.  */
    221   int size;
    222 
    223   /* # bytes the prologue should push and pretend that the caller pushed them.
    224      The prologue must do this, but only if parms can be passed in
    225      registers.  */
    226   int pretend_args_size;
    227 
    228   /* This is the offset from the arg pointer to the place where the first
    229      anonymous arg can be found, if there is one.  */
    230   rtx arg_offset_rtx;
    231 
    232   /* Quantities of various kinds of registers
    233      used for the current function's args.  */
    234   CUMULATIVE_ARGS info;
    235 
    236   /* The arg pointer hard register, or the pseudo into which it was copied.  */
    237   rtx internal_arg_pointer;
    238 };
    239 
    240 /* Data for function partitioning.  */
    241 struct function_subsections GTY(())
    242 {
    243   /* Assembly labels for the hot and cold text sections, to
    244      be used by debugger functions for determining the size of text
    245      sections.  */
    246 
    247   const char *hot_section_label;
    248   const char *cold_section_label;
    249   const char *hot_section_end_label;
    250   const char *cold_section_end_label;
    251 
    252   /* String to be used for name of cold text sections, via
    253      targetm.asm_out.named_section.  */
    254 
    255   const char *unlikely_text_section_name;
    256 };
    257 
    258 /* Datastructures maintained for currently processed function in RTL form.  */
    259 struct rtl_data GTY(())
    260 {
    261   struct expr_status expr;
    262   struct emit_status emit;
    263   struct varasm_status varasm;
    264   struct incoming_args args;
    265   struct function_subsections subsections;
    266   struct rtl_eh eh;
    267 
    268   /* For function.c  */
    269 
    270   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
    271      defined, the needed space is pushed by the prologue.  */
    272   int outgoing_args_size;
    273 
    274   /* If nonzero, an RTL expression for the location at which the current
    275      function returns its result.  If the current function returns its
    276      result in a register, current_function_return_rtx will always be
    277      the hard register containing the result.  */
    278   rtx return_rtx;
    279 
    280   /* Opaque pointer used by get_hard_reg_initial_val and
    281      has_hard_reg_initial_val (see integrate.[hc]).  */
    282   struct initial_value_struct *hard_reg_initial_vals;
    283 
    284   /* A variable living at the top of the frame that holds a known value.
    285      Used for detecting stack clobbers.  */
    286   tree stack_protect_guard;
    287 
    288   /* List (chain of EXPR_LIST) of labels heading the current handlers for
    289      nonlocal gotos.  */
    290   rtx x_nonlocal_goto_handler_labels;
    291 
    292   /* Label that will go on function epilogue.
    293      Jumping to this label serves as a "return" instruction
    294      on machines which require execution of the epilogue on all returns.  */
    295   rtx x_return_label;
    296 
    297   /* Label that will go on the end of function epilogue.
    298      Jumping to this label serves as a "naked return" instruction
    299      on machines which require execution of the epilogue on all returns.  */
    300   rtx x_naked_return_label;
    301 
    302   /* List (chain of EXPR_LISTs) of all stack slots in this function.
    303      Made for the sake of unshare_all_rtl.  */
    304   rtx x_stack_slot_list;
    305 
    306   /* Place after which to insert the tail_recursion_label if we need one.  */
    307   rtx x_stack_check_probe_note;
    308 
    309   /* Location at which to save the argument pointer if it will need to be
    310      referenced.  There are two cases where this is done: if nonlocal gotos
    311      exist, or if vars stored at an offset from the argument pointer will be
    312      needed by inner routines.  */
    313   rtx x_arg_pointer_save_area;
    314 
    315   /* Dynamic Realign Argument Pointer used for realigning stack.  */
    316   rtx drap_reg;
    317 
    318   /* Offset to end of allocated area of stack frame.
    319      If stack grows down, this is the address of the last stack slot allocated.
    320      If stack grows up, this is the address for the next slot.  */
    321   HOST_WIDE_INT x_frame_offset;
    322 
    323   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
    324   rtx x_parm_birth_insn;
    325 
    326   /* List of all used temporaries allocated, by level.  */
    327   VEC(temp_slot_p,gc) *x_used_temp_slots;
    328 
    329   /* List of available temp slots.  */
    330   struct temp_slot *x_avail_temp_slots;
    331 
    332   /* Current nesting level for temporaries.  */
    333   int x_temp_slot_level;
    334 
    335   /* The largest alignment needed on the stack, including requirement
    336      for outgoing stack alignment.  */
    337   unsigned int stack_alignment_needed;
    338 
    339   /* Preferred alignment of the end of stack frame, which is preferred
    340      to call other functions.  */
    341   unsigned int preferred_stack_boundary;
    342 
    343   /* The minimum alignment of parameter stack.  */
    344   unsigned int parm_stack_boundary;
    345 
    346   /* The largest alignment of slot allocated on the stack.  */
    347   unsigned int max_used_stack_slot_alignment;
    348 
    349   /* The stack alignment estimated before reload, with consideration of
    350      following factors:
    351      1. Alignment of local stack variables (max_used_stack_slot_alignment)
    352      2. Alignment requirement to call other functions
    353         (preferred_stack_boundary)
    354      3. Alignment of non-local stack variables but might be spilled in
    355         local stack.  */
    356   unsigned int stack_alignment_estimated;
    357 
    358   /* For reorg.  */
    359 
    360   /* If some insns can be deferred to the delay slots of the epilogue, the
    361      delay list for them is recorded here.  */
    362   rtx epilogue_delay_list;
    363 
    364   /* Nonzero if function being compiled called builtin_return_addr or
    365      builtin_frame_address with nonzero count.  */
    366   bool accesses_prior_frames;
    367 
    368   /* Nonzero if the function calls __builtin_eh_return.  */
    369   bool calls_eh_return;
    370 
    371   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
    372      label that can reach the exit block via non-exceptional paths. */
    373   bool saves_all_registers;
    374 
    375   /* Nonzero if function being compiled has nonlocal gotos to parent
    376      function.  */
    377   bool has_nonlocal_goto;
    378 
    379   /* Nonzero if function being compiled has an asm statement.  */
    380   bool has_asm_statement;
    381 
    382   /* This bit is used by the exception handling logic.  It is set if all
    383      calls (if any) are sibling calls.  Such functions do not have to
    384      have EH tables generated, as they cannot throw.  A call to such a
    385      function, however, should be treated as throwing if any of its callees
    386      can throw.  */
    387   bool all_throwers_are_sibcalls;
    388 
    389   /* Nonzero if stack limit checking should be enabled in the current
    390      function.  */
    391   bool limit_stack;
    392 
    393   /* Nonzero if profiling code should be generated.  */
    394   bool profile;
    395 
    396   /* Nonzero if the current function uses the constant pool.  */
    397   bool uses_const_pool;
    398 
    399   /* Nonzero if the current function uses pic_offset_table_rtx.  */
    400   bool uses_pic_offset_table;
    401 
    402   /* Nonzero if the current function needs an lsda for exception handling.  */
    403   bool uses_eh_lsda;
    404 
    405   /* Set when the tail call has been produced.  */
    406   bool tail_call_emit;
    407 
    408   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
    409   bool arg_pointer_save_area_init;
    410 
    411   /* Nonzero if current function must be given a frame pointer.
    412      Set in global.c if anything is allocated on the stack there.  */
    413   bool frame_pointer_needed;
    414 
    415   /* When set, expand should optimize for speed.  */
    416   bool maybe_hot_insn_p;
    417 
    418   /* Nonzero if function stack realignment is needed.  This flag may be
    419      set twice: before and after reload.  It is set before reload wrt
    420      stack alignment estimation before reload.  It will be changed after
    421      reload if by then criteria of stack realignment is different.
    422      The value set after reload is the accurate one and is finalized.  */
    423   bool stack_realign_needed;
    424 
    425   /* Nonzero if function stack realignment is tried.  This flag is set
    426      only once before reload.  It affects register elimination.  This
    427      is used to generate DWARF debug info for stack variables.  */
    428   bool stack_realign_tried;
    429 
    430   /* Nonzero if function being compiled needs dynamic realigned
    431      argument pointer (drap) if stack needs realigning.  */
    432   bool need_drap;
    433 
    434   /* Nonzero if function stack realignment estimation is done, namely
    435      stack_realign_needed flag has been set before reload wrt estimated
    436      stack alignment info.  */
    437   bool stack_realign_processed;
    438 
    439   /* Nonzero if function stack realignment has been finalized, namely
    440      stack_realign_needed flag has been set and finalized after reload.  */
    441   bool stack_realign_finalized;
    442 
    443   /* True if dbr_schedule has already been called for this function.  */
    444   bool dbr_scheduled_p;
    445 };
    446 
    447 #define return_label (crtl->x_return_label)
    448 #define naked_return_label (crtl->x_naked_return_label)
    449 #define stack_slot_list (crtl->x_stack_slot_list)
    450 #define parm_birth_insn (crtl->x_parm_birth_insn)
    451 #define frame_offset (crtl->x_frame_offset)
    452 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
    453 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
    454 #define used_temp_slots (crtl->x_used_temp_slots)
    455 #define avail_temp_slots (crtl->x_avail_temp_slots)
    456 #define temp_slot_level (crtl->x_temp_slot_level)
    457 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
    458 #define frame_pointer_needed (crtl->frame_pointer_needed)
    459 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
    460 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
    461 
    462 extern GTY(()) struct rtl_data x_rtl;
    463 
    464 /* Accessor to RTL datastructures.  We keep them statically allocated now since
    465    we never keep multiple functions.  For threaded compiler we might however
    466    want to do differently.  */
    467 #define crtl (&x_rtl)
    468 
    469 /* This structure can save all the important global and static variables
    470    describing the status of the current function.  */
    471 
    472 struct function GTY(())
    473 {
    474   struct eh_status *eh;
    475 
    476   /* The control flow graph for this function.  */
    477   struct control_flow_graph *cfg;
    478 
    479   /* GIMPLE body for this function.  */
    480   struct gimple_seq_d *gimple_body;
    481 
    482   /* SSA and dataflow information.  */
    483   struct gimple_df *gimple_df;
    484 
    485   /* The loops in this function.  */
    486   struct loops *x_current_loops;
    487 
    488   /* Value histograms attached to particular statements.  */
    489   htab_t GTY((skip)) value_histograms;
    490 
    491   /* For function.c.  */
    492 
    493   /* Points to the FUNCTION_DECL of this function.  */
    494   tree decl;
    495 
    496   /* A PARM_DECL that should contain the static chain for this function.
    497      It will be initialized at the beginning of the function.  */
    498   tree static_chain_decl;
    499 
    500   /* An expression that contains the non-local goto save area.  The first
    501      word is the saved frame pointer and the second is the saved stack
    502      pointer.  */
    503   tree nonlocal_goto_save_area;
    504 
    505   /* Function's module id.  */
    506   unsigned module_id;
    507 
    508   /* Function sequence number for profiling, debugging, etc.  */
    509   int funcdef_no;
    510 
    511   /* List of function local variables, functions, types and constants.  */
    512   tree local_decls;
    513 
    514   /* For md files.  */
    515 
    516   /* tm.h can use this to store whatever it likes.  */
    517   struct machine_function * GTY ((maybe_undef)) machine;
    518 
    519   /* Language-specific code can use this to store whatever it likes.  */
    520   struct language_function * language;
    521 
    522   /* Used types hash table.  */
    523   htab_t GTY ((param_is (union tree_node))) used_types_hash;
    524 
    525   /* Map between variables synthesized in stack_overlay to the original
    526      variables. Used in RTL emission.*/
    527   htab_t GTY ((param_is (struct overlay_decl_mapping))) union_decl_list_map;
    528 
    529   /* Last statement uid.  */
    530   int last_stmt_uid;
    531 
    532   /* Line number of the start of the function for debugging purposes.  */
    533   location_t function_start_locus;
    534 
    535   /* Line number of the end of the function.  */
    536   location_t function_end_locus;
    537 
    538   /* Properties used by the pass manager.  */
    539   unsigned int curr_properties;
    540   unsigned int last_verified;
    541   /* Interprocedural passes scheduled to have their transform functions
    542      applied next time we execute local pass on them.  We maintain it
    543      per-function in order to allow IPA passes to introduce new functions.  */
    544   VEC(ipa_opt_pass,heap) * GTY((skip)) ipa_transforms_to_apply;
    545 
    546   /* Collected bit flags.  */
    547 
    548   /* Number of units of general registers that need saving in stdarg
    549      function.  What unit is depends on the backend, either it is number
    550      of bytes, or it can be number of registers.  */
    551   unsigned int va_list_gpr_size : 8;
    552 
    553   /* Number of units of floating point registers that need saving in stdarg
    554      function.  */
    555   unsigned int va_list_fpr_size : 8;
    556 
    557 
    558   /* How commonly executed the function is.  Initialized during branch
    559      probabilities pass.  */
    560   ENUM_BITFIELD (function_frequency) function_frequency : 2;
    561 
    562   /* Nonzero if function being compiled can call setjmp.  */
    563   unsigned int calls_setjmp : 1;
    564 
    565   /* Nonzero if function being compiled can call alloca,
    566      either as a subroutine or builtin.  */
    567   unsigned int calls_alloca : 1;
    568 
    569   /* Nonzero if function being compiled receives nonlocal gotos
    570      from nested functions.  */
    571   unsigned int has_nonlocal_label : 1;
    572 
    573   /* Nonzero if current function uses stdarg.h or equivalent.  */
    574   unsigned int stdarg : 1;
    575 
    576   /* Nonzero if the back-end should not keep track of expressions that
    577      determine the size of variable-sized objects.  Normally, such
    578      expressions are saved away, and then expanded when the next
    579      function is started.  For example, if a parameter has a
    580      variable-sized type, then the size of the parameter is computed
    581      when the function body is entered.  However, some front-ends do
    582      not desire this behavior.  */
    583   unsigned int dont_save_pending_sizes_p : 1;
    584 
    585   unsigned int after_inlining : 1;
    586   unsigned int always_inline_functions_inlined : 1;
    587 
    588   /* Fields below this point are not set for abstract functions; see
    589      allocate_struct_function.  */
    590 
    591   /* Nonzero if function being compiled needs to be given an address
    592      where the value should be stored.  */
    593   unsigned int returns_struct : 1;
    594 
    595   /* Nonzero if function being compiled needs to
    596      return the address of where it has put a structure value.  */
    597   unsigned int returns_pcc_struct : 1;
    598 
    599   /* Nonzero if pass_tree_profile was run on this function.  */
    600   unsigned int after_tree_profile : 1;
    601 
    602   /* Nonzero if this function has local DECL_HARD_REGISTER variables.
    603      In this case code motion has to be done more carefully.  */
    604   unsigned int has_local_explicit_reg_vars : 1;
    605 
    606   /* Nonzero if the current function is a thunk, i.e., a lightweight
    607      function implemented by the output_mi_thunk hook) that just
    608      adjusts one of its arguments and forwards to another
    609      function.  */
    610   unsigned int is_thunk : 1;
    611 };
    612 
    613 /* The bit width of function id in the global function id used
    614    in LIPO.  */
    615 #define FUNC_ID_WIDTH HOST_BITS_PER_WIDEST_INT / 2
    616 /* The mask to extract function id from the global function id.  */
    617 #define FUNC_ID_MASK ((1ll << FUNC_ID_WIDTH) - 1)
    618 /* Macro to extract module id from global function id GID.  */
    619 #define EXTRACT_MODULE_ID_FROM_GLOBAL_ID(gid) (unsigned)(((gid) >>\
    620                                         FUNC_ID_WIDTH) & FUNC_ID_MASK)
    621 /* Macro to extract function id from global function id GID.  */
    622 #define EXTRACT_FUNC_ID_FROM_GLOBAL_ID(gid) (unsigned)((gid) & FUNC_ID_MASK)
    623 /* Macro to generate a global function id from module id M and
    624    function id F.  */
    625 #define GEN_FUNC_GLOBAL_ID(m,f) ((((HOST_WIDEST_INT) (m)) << FUNC_ID_WIDTH)\
    626                                  | (f))
    627 /* Access macro for module_id field of function FUNC.  */
    628 #define FUNC_DECL_MODULE_ID(func) ((func)->module_id)
    629 /* Access macro for funcdef_no field of function FUNC.  */
    630 #define FUNC_DECL_FUNC_ID(func)   ((func)->funcdef_no + 1)
    631 /* Macro to compute global function id for FUNC.  */
    632 #define FUNC_DECL_GLOBAL_ID(func) \
    633   GEN_FUNC_GLOBAL_ID (FUNC_DECL_MODULE_ID (func), FUNC_DECL_FUNC_ID (func))
    634 /* 32 bit wide unique id used for asm label (limit: 30k modules,
    635    128k funcs per module.  */
    636 #define FUNC_LABEL_ID(func) ((FUNC_DECL_MODULE_ID (func) << 17) +\
    637                              (func)->funcdef_no)
    638 
    639 /* If va_list_[gf]pr_size is set to this, it means we don't know how
    640    many units need to be saved.  */
    641 #define VA_LIST_MAX_GPR_SIZE	255
    642 #define VA_LIST_MAX_FPR_SIZE	255
    643 
    644 /* The function currently being compiled.  */
    645 extern GTY(()) struct function *cfun;
    646 
    647 /* In order to ensure that cfun is not set directly, we redefine it so
    648    that it is not an lvalue.  Rather than assign to cfun, use
    649    push_cfun or set_cfun.  */
    650 #define cfun (cfun + 0)
    651 
    652 /* Nonzero if we've already converted virtual regs to hard regs.  */
    653 extern int virtuals_instantiated;
    654 
    655 /* Nonzero if at least one trampoline has been created.  */
    656 extern int trampolines_created;
    657 
    658 struct types_used_by_vars_entry GTY(()) {
    659   tree type;
    660   tree var_decl;
    661 };
    662 
    663 /* Hash table making the relationship between a global variable
    664    and the types it references in its initializer. The key of the
    665    entry is a referenced type, and the value is the DECL of the global
    666    variable. types_use_by_vars_do_hash and types_used_by_vars_eq below are
    667    the hash and equality functions to use for this hash table.  */
    668 extern GTY((param_is (struct types_used_by_vars_entry))) htab_t
    669   types_used_by_vars_hash;
    670 
    671 hashval_t types_used_by_vars_do_hash (const void*);
    672 int types_used_by_vars_eq (const void *, const void *);
    673 void types_used_by_var_decl_insert (tree type, tree var_decl);
    674 
    675 /* During parsing of a global variable, this linked list points to
    676    the list of types referenced by the global variable.  */
    677 extern GTY(()) tree types_used_by_cur_var_decl;
    678 
    679 
    680 /* cfun shouldn't be set directly; use one of these functions instead.  */
    681 extern void set_cfun (struct function *new_cfun);
    682 extern void push_cfun (struct function *new_cfun);
    683 extern void pop_cfun (void);
    684 extern void instantiate_decl_rtl (rtx x);
    685 
    686 /* For backward compatibility... eventually these should all go away.  */
    687 #define current_function_funcdef_no (cfun->funcdef_no)
    688 
    689 #define current_loops (cfun->x_current_loops)
    690 #define dom_computed (cfun->cfg->x_dom_computed)
    691 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
    692 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
    693 
    694 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
    695    and create duplicate blocks.  */
    696 extern void reorder_blocks (void);
    697 
    698 /* Set BLOCK_NUMBER for all the blocks in FN.  */
    699 extern void number_blocks (tree);
    700 
    701 extern void clear_block_marks (tree);
    702 extern tree blocks_nreverse (tree);
    703 
    704 /* Return size needed for stack frame based on slots so far allocated.
    705    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
    706    the caller may have to do that.  */
    707 extern HOST_WIDE_INT get_frame_size (void);
    708 
    709 /* Issue an error message and return TRUE if frame OFFSET overflows in
    710    the signed target pointer arithmetics for function FUNC.  Otherwise
    711    return FALSE.  */
    712 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
    713 
    714 /* A pointer to a function to create target specific, per-function
    715    data structures.  */
    716 extern struct machine_function * (*init_machine_status) (void);
    717 
    718 /* Save and restore status information for a nested function.  */
    719 extern void free_after_parsing (struct function *);
    720 extern void free_after_compilation (struct function *);
    721 
    722 extern void init_varasm_status (void);
    723 
    724 #ifdef RTX_CODE
    725 extern void diddle_return_value (void (*)(rtx, void*), void*);
    726 extern void clobber_return_register (void);
    727 #endif
    728 
    729 extern rtx get_arg_pointer_save_area (void);
    730 
    731 /* Returns the name of the current function.  */
    732 extern const char *current_function_name (void);
    733 /* Returns the assembler name (raw, mangled) of the current function.  */
    734 extern const char *current_function_assembler_name (void);
    735 
    736 extern void do_warn_unused_parameter (tree);
    737 
    738 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
    739 			       tree, bool);
    740 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
    741 				     tree, bool);
    742 
    743 extern void used_types_insert (tree);
    744 
    745 extern int get_next_funcdef_no (void);
    746 extern int get_current_funcdef_no (void);
    747 
    748 extern void reset_funcdef_no (void);
    749 extern void set_funcdef_no (int);
    750 #endif  /* GCC_FUNCTION_H */
    751