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      1 /* Hooks for cfg representation specific functions.
      2    Copyright (C) 2003-2013 Free Software Foundation, Inc.
      3    Contributed by Sebastian Pop <s.pop (at) laposte.net>
      4 
      5 This file is part of GCC.
      6 
      7 GCC is free software; you can redistribute it and/or modify
      8 it under the terms of the GNU General Public License as published by
      9 the Free Software Foundation; either version 3, or (at your option)
     10 any later version.
     11 
     12 GCC is distributed in the hope that it will be useful,
     13 but WITHOUT ANY WARRANTY; without even the implied warranty of
     14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     15 GNU General Public License for more details.
     16 
     17 You should have received a copy of the GNU General Public License
     18 along with GCC; see the file COPYING3.  If not see
     19 <http://www.gnu.org/licenses/>.  */
     20 
     21 /* Only basic-block.h includes this.  */
     22 
     23 struct cfg_hooks
     24 {
     25   /* Name of the corresponding ir.  */
     26   const char *name;
     27 
     28   /* Debugging.  */
     29   int (*verify_flow_info) (void);
     30   void (*dump_bb) (FILE *, basic_block, int, int);
     31   void (*dump_bb_for_graph) (pretty_printer *, basic_block);
     32 
     33   /* Basic CFG manipulation.  */
     34 
     35   /* Return new basic block.  */
     36   basic_block (*create_basic_block) (void *head, void *end, basic_block after);
     37 
     38   /* Redirect edge E to the given basic block B and update underlying program
     39      representation.  Returns edge representing redirected branch (that may not
     40      be equivalent to E in the case of duplicate edges being removed) or NULL
     41      if edge is not easily redirectable for whatever reason.  */
     42   edge (*redirect_edge_and_branch) (edge e, basic_block b);
     43 
     44   /* Same as the above but allows redirecting of fallthru edges.  In that case
     45      newly created forwarder basic block is returned.  The edge must
     46      not be abnormal.  */
     47   basic_block (*redirect_edge_and_branch_force) (edge, basic_block);
     48 
     49   /* Returns true if it is possible to remove the edge by redirecting it
     50      to the destination of the other edge going from its source.  */
     51   bool (*can_remove_branch_p) (const_edge);
     52 
     53   /* Remove statements corresponding to a given basic block.  */
     54   void (*delete_basic_block) (basic_block);
     55 
     56   /* Creates a new basic block just after basic block B by splitting
     57      everything after specified instruction I.  */
     58   basic_block (*split_block) (basic_block b, void * i);
     59 
     60   /* Move block B immediately after block A.  */
     61   bool (*move_block_after) (basic_block b, basic_block a);
     62 
     63   /* Return true when blocks A and B can be merged into single basic block.  */
     64   bool (*can_merge_blocks_p) (basic_block a, basic_block b);
     65 
     66   /* Merge blocks A and B.  */
     67   void (*merge_blocks) (basic_block a, basic_block b);
     68 
     69   /* Predict edge E using PREDICTOR to given PROBABILITY.  */
     70   void (*predict_edge) (edge e, enum br_predictor predictor, int probability);
     71 
     72   /* Return true if the one of outgoing edges is already predicted by
     73      PREDICTOR.  */
     74   bool (*predicted_by_p) (const_basic_block bb, enum br_predictor predictor);
     75 
     76   /* Return true when block A can be duplicated.  */
     77   bool (*can_duplicate_block_p) (const_basic_block a);
     78 
     79   /* Duplicate block A.  */
     80   basic_block (*duplicate_block) (basic_block a);
     81 
     82   /* Higher level functions representable by primitive operations above if
     83      we didn't have some oddities in RTL and Tree representations.  */
     84   basic_block (*split_edge) (edge);
     85   void (*make_forwarder_block) (edge);
     86 
     87   /* Try to make the edge fallthru.  */
     88   void (*tidy_fallthru_edge) (edge);
     89 
     90   /* Make the edge non-fallthru.  */
     91   basic_block (*force_nonfallthru) (edge);
     92 
     93   /* Say whether a block ends with a call, possibly followed by some
     94      other code that must stay with the call.  */
     95   bool (*block_ends_with_call_p) (basic_block);
     96 
     97   /* Say whether a block ends with a conditional branch.  Switches
     98      and unconditional branches do not qualify.  */
     99   bool (*block_ends_with_condjump_p) (const_basic_block);
    100 
    101   /* Add fake edges to the function exit for any non constant and non noreturn
    102      calls, volatile inline assembly in the bitmap of blocks specified by
    103      BLOCKS or to the whole CFG if BLOCKS is zero.  Return the number of blocks
    104      that were split.
    105 
    106      The goal is to expose cases in which entering a basic block does not imply
    107      that all subsequent instructions must be executed.  */
    108   int (*flow_call_edges_add) (sbitmap);
    109 
    110   /* This function is called immediately after edge E is added to the
    111      edge vector E->dest->preds.  */
    112   void (*execute_on_growing_pred) (edge);
    113 
    114   /* This function is called immediately before edge E is removed from
    115      the edge vector E->dest->preds.  */
    116   void (*execute_on_shrinking_pred) (edge);
    117 
    118   /* A hook for duplicating loop in CFG, currently this is used
    119      in loop versioning.  */
    120   bool (*cfg_hook_duplicate_loop_to_header_edge) (struct loop *, edge,
    121 						  unsigned, sbitmap,
    122 						  edge, vec<edge> *,
    123 						  int);
    124 
    125   /* Add condition to new basic block and update CFG used in loop
    126      versioning.  */
    127   void (*lv_add_condition_to_bb) (basic_block, basic_block, basic_block,
    128 				  void *);
    129   /* Update the PHI nodes in case of loop versioning.  */
    130   void (*lv_adjust_loop_header_phi) (basic_block, basic_block,
    131 				     basic_block, edge);
    132 
    133   /* Given a condition BB extract the true/false taken/not taken edges
    134      (depending if we are on tree's or RTL). */
    135   void (*extract_cond_bb_edges) (basic_block, edge *, edge *);
    136 
    137 
    138   /* Add PHI arguments queued in PENDINT_STMT list on edge E to edge
    139      E->dest (only in tree-ssa loop versioning.  */
    140   void (*flush_pending_stmts) (edge);
    141 
    142   /* True if a block contains no executable instructions.  */
    143   bool (*empty_block_p) (basic_block);
    144 
    145   /* Split a basic block if it ends with a conditional branch and if
    146      the other part of the block is not empty.  */
    147   basic_block (*split_block_before_cond_jump) (basic_block);
    148 
    149   /* Do book-keeping of a basic block for the profile consistency checker.  */
    150   void (*account_profile_record) (basic_block, int, struct profile_record *);
    151 };
    152 
    153 extern void verify_flow_info (void);
    154 extern void dump_bb (FILE *, basic_block, int, int);
    155 extern void dump_bb_for_graph (pretty_printer *, basic_block);
    156 
    157 extern edge redirect_edge_and_branch (edge, basic_block);
    158 extern basic_block redirect_edge_and_branch_force (edge, basic_block);
    159 extern bool can_remove_branch_p (const_edge);
    160 extern void remove_branch (edge);
    161 extern void remove_edge (edge);
    162 extern edge split_block (basic_block, void *);
    163 extern edge split_block_after_labels (basic_block);
    164 extern bool move_block_after (basic_block, basic_block);
    165 extern void delete_basic_block (basic_block);
    166 extern basic_block split_edge (edge);
    167 extern basic_block create_basic_block (void *, void *, basic_block);
    168 extern basic_block create_empty_bb (basic_block);
    169 extern bool can_merge_blocks_p (basic_block, basic_block);
    170 extern void merge_blocks (basic_block, basic_block);
    171 extern edge make_forwarder_block (basic_block, bool (*)(edge),
    172 				  void (*) (basic_block));
    173 extern basic_block force_nonfallthru (edge);
    174 extern void tidy_fallthru_edge (edge);
    175 extern void tidy_fallthru_edges (void);
    176 extern void predict_edge (edge e, enum br_predictor predictor, int probability);
    177 extern bool predicted_by_p (const_basic_block bb, enum br_predictor predictor);
    178 extern bool can_duplicate_block_p (const_basic_block);
    179 extern basic_block duplicate_block (basic_block, edge, basic_block);
    180 extern bool block_ends_with_call_p (basic_block bb);
    181 extern bool empty_block_p (basic_block);
    182 extern basic_block split_block_before_cond_jump (basic_block);
    183 extern bool block_ends_with_condjump_p (const_basic_block bb);
    184 extern int flow_call_edges_add (sbitmap);
    185 extern void execute_on_growing_pred (edge);
    186 extern void execute_on_shrinking_pred (edge);
    187 extern bool cfg_hook_duplicate_loop_to_header_edge (struct loop *loop, edge,
    188 						    unsigned int ndupl,
    189 						    sbitmap wont_exit,
    190 						    edge orig,
    191 						    vec<edge> *to_remove,
    192 						    int flags);
    193 
    194 extern void lv_flush_pending_stmts (edge);
    195 extern void extract_cond_bb_edges (basic_block, edge *, edge*);
    196 extern void lv_adjust_loop_header_phi (basic_block, basic_block, basic_block,
    197 				       edge);
    198 extern void lv_add_condition_to_bb (basic_block, basic_block, basic_block,
    199 				    void *);
    200 
    201 extern bool can_copy_bbs_p (basic_block *, unsigned);
    202 extern void copy_bbs (basic_block *, unsigned, basic_block *,
    203 		      edge *, unsigned, edge *, struct loop *,
    204 		      basic_block);
    205 
    206 void account_profile_record (struct profile_record *, int);
    207 
    208 extern void cfg_layout_initialize (unsigned int);
    209 extern void cfg_layout_finalize (void);
    210 
    211 /* Hooks containers.  */
    212 extern struct cfg_hooks gimple_cfg_hooks;
    213 extern struct cfg_hooks rtl_cfg_hooks;
    214 extern struct cfg_hooks cfg_layout_rtl_cfg_hooks;
    215 
    216 /* Declarations.  */
    217 extern enum ir_type current_ir_type (void);
    218 extern void rtl_register_cfg_hooks (void);
    219 extern void cfg_layout_rtl_register_cfg_hooks (void);
    220 extern void gimple_register_cfg_hooks (void);
    221 extern struct cfg_hooks get_cfg_hooks (void);
    222 extern void set_cfg_hooks (struct cfg_hooks);
    223 
    224