gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
   3    Free Software Foundation, Inc.
   4    Contributed by Jan Hubicka
   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 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "tree-flow.h"
  28 #include "langhooks.h"
  29 #include "pointer-set.h"
  30 #include "cgraph.h"
  31 #include "intl.h"
  32 #include "gimple.h"
  33 #include "tree-pass.h"
  34
  35 /* Walk tree and record all calls and references to functions/variables.
  36    Called via walk_tree: TP is pointer to tree to be examined.
  37    When DATA is non-null, record references to callgraph.
  38    */
  39
  40 static tree
  41 record_reference (tree *tp, int *walk_subtrees, void *data)
  42 {
  43   tree t = *tp;
  44   tree decl;
  45   bool do_callgraph = data != NULL;
  46
  47   switch (TREE_CODE (t))
  48     {
  49     case VAR_DECL:
  50       if (TREE_STATIC (t) || DECL_EXTERNAL (t))
  51         {
  52           varpool_mark_needed_node (varpool_node (t));
  53           if (lang_hooks.callgraph.analyze_expr)
  54             return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
  55         }
  56       break;
  57
  58     case FDESC_EXPR:
  59     case ADDR_EXPR:
  60       /* Record dereferences to the functions.  This makes the
  61          functions reachable unconditionally.  */
  62       decl = TREE_OPERAND (*tp, 0);
  63       if (TREE_CODE (decl) == FUNCTION_DECL && do_callgraph)
  64         cgraph_mark_address_taken_node (cgraph_node (decl));
  65       break;
  66
  67     default:
  68       /* Save some cycles by not walking types and declaration as we
  69          won't find anything useful there anyway.  */
  70       if (IS_TYPE_OR_DECL_P (*tp))
  71         {
  72           *walk_subtrees = 0;
  73           break;
  74         }
  75
  76       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
  77         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
  78       break;
  79     }
  80
  81   return NULL_TREE;
  82 }
  83
  84 /* Reset inlining information of all incoming call edges of NODE.  */
  85
  86 void
  87 reset_inline_failed (struct cgraph_node *node)
  88 {
  89   struct cgraph_edge *e;
  90
  91   for (e = node->callers; e; e = e->next_caller)
  92     {
  93       e->callee->global.inlined_to = NULL;
  94       if (!node->analyzed)
  95         e->inline_failed = CIF_BODY_NOT_AVAILABLE;
  96       else if (node->local.redefined_extern_inline)
  97         e->inline_failed = CIF_REDEFINED_EXTERN_INLINE;
  98       else if (!node->local.inlinable)
  99         e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
 100       else if (e->call_stmt_cannot_inline_p)
 101         e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
 102       else
 103         e->inline_failed = CIF_FUNCTION_NOT_CONSIDERED;
 104     }
 105 }
 106
 107 /* Computes the frequency of the call statement so that it can be stored in
 108    cgraph_edge.  BB is the basic block of the call statement.  */
 109 int
 110 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 111 {
 112   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 113                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 114   int freq = bb->frequency;
 115
 116   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 117     return CGRAPH_FREQ_BASE;
 118
 119   if (!entry_freq)
 120     entry_freq = 1, freq++;
 121
 122   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 123   if (freq > CGRAPH_FREQ_MAX)
 124     freq = CGRAPH_FREQ_MAX;
 125
 126   return freq;
 127 }
 128
 129 /* Create cgraph edges for function calls.
 130    Also look for functions and variables having addresses taken.  */
 131
 132 static unsigned int
 133 build_cgraph_edges (void)
 134 {
 135   basic_block bb;
 136   struct cgraph_node *node = cgraph_node (current_function_decl);
 137   struct pointer_set_t *visited_nodes = pointer_set_create ();
 138   gimple_stmt_iterator gsi;
 139   tree step;
 140
 141   /* Create the callgraph edges and record the nodes referenced by the function.
 142      body.  */
 143   FOR_EACH_BB (bb)
 144     for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 145       {
 146         gimple stmt = gsi_stmt (gsi);
 147         tree decl;
 148
 149         if (is_gimple_call (stmt) && (decl = gimple_call_fndecl (stmt)))
 150           {
 151             size_t i;
 152             size_t n = gimple_call_num_args (stmt);
 153             cgraph_create_edge (node, cgraph_node (decl), stmt,
 154                                 bb->count, compute_call_stmt_bb_frequency (current_function_decl, bb),
 155                                 bb->loop_depth);
 156             for (i = 0; i < n; i++)
 157               walk_tree (gimple_call_arg_ptr (stmt, i), record_reference,
 158                          node, visited_nodes);
 159             if (gimple_call_lhs (stmt))
 160               walk_tree (gimple_call_lhs_ptr (stmt), record_reference, node,
 161                          visited_nodes);
 162           }
 163         else
 164           {
 165             struct walk_stmt_info wi;
 166             memset (&wi, 0, sizeof (wi));
 167             wi.info = node;
 168             wi.pset = visited_nodes;
 169             walk_gimple_op (stmt, record_reference, &wi);
 170             if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 171                 && gimple_omp_parallel_child_fn (stmt))
 172               {
 173                 tree fn = gimple_omp_parallel_child_fn (stmt);
 174                 cgraph_mark_needed_node (cgraph_node (fn));
 175               }
 176             if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 177               {
 178                 tree fn = gimple_omp_task_child_fn (stmt);
 179                 if (fn)
 180                   cgraph_mark_needed_node (cgraph_node (fn));
 181                 fn = gimple_omp_task_copy_fn (stmt);
 182                 if (fn)
 183                   cgraph_mark_needed_node (cgraph_node (fn));
 184               }
 185           }
 186       }
 187
 188   /* Look for initializers of constant variables and private statics.  */
 189   for (step = cfun->local_decls;
 190        step;
 191        step = TREE_CHAIN (step))
 192     {
 193       tree decl = TREE_VALUE (step);
 194       if (TREE_CODE (decl) == VAR_DECL
 195           && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 196         varpool_finalize_decl (decl);
 197       else if (TREE_CODE (decl) == VAR_DECL && DECL_INITIAL (decl))
 198         walk_tree (&DECL_INITIAL (decl), record_reference, node, visited_nodes);
 199     }
 200
 201   pointer_set_destroy (visited_nodes);
 202   return 0;
 203 }
 204
 205 struct gimple_opt_pass pass_build_cgraph_edges =
 206 {
 207  {
 208   GIMPLE_PASS,
 209   "*build_cgraph_edges",                        /* name */
 210   NULL,                                 /* gate */
 211   build_cgraph_edges,                   /* execute */
 212   NULL,                                 /* sub */
 213   NULL,                                 /* next */
 214   0,                                    /* static_pass_number */
 215   TV_NONE,                              /* tv_id */
 216   PROP_cfg,                             /* properties_required */
 217   0,                                    /* properties_provided */
 218   0,                                    /* properties_destroyed */
 219   0,                                    /* todo_flags_start */
 220   0                                     /* todo_flags_finish */
 221  }
 222 };
 223
 224 /* Record references to functions and other variables present in the
 225    initial value of DECL, a variable.
 226    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 227
 228 void
 229 record_references_in_initializer (tree decl, bool only_vars)
 230 {
 231   struct pointer_set_t *visited_nodes = pointer_set_create ();
 232   walk_tree (&DECL_INITIAL (decl), record_reference,
 233             only_vars ? NULL : decl, visited_nodes);
 234   pointer_set_destroy (visited_nodes);
 235 }
 236
 237 /* Rebuild cgraph edges for current function node.  This needs to be run after
 238    passes that don't update the cgraph.  */
 239
 240 unsigned int
 241 rebuild_cgraph_edges (void)
 242 {
 243   basic_block bb;
 244   struct cgraph_node *node = cgraph_node (current_function_decl);
 245   gimple_stmt_iterator gsi;
 246
 247   cgraph_node_remove_callees (node);
 248
 249   node->count = ENTRY_BLOCK_PTR->count;
 250
 251   FOR_EACH_BB (bb)
 252     for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 253       {
 254         gimple stmt = gsi_stmt (gsi);
 255         tree decl;
 256
 257         if (is_gimple_call (stmt) && (decl = gimple_call_fndecl (stmt)))
 258           cgraph_create_edge (node, cgraph_node (decl), stmt,
 259                               bb->count,
 260                               compute_call_stmt_bb_frequency
 261                                 (current_function_decl, bb),
 262                               bb->loop_depth);
 263
 264       }
 265   gcc_assert (!node->global.inlined_to);
 266
 267   return 0;
 268 }
 269
 270 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 271 {
 272  {
 273   GIMPLE_PASS,
 274   "*rebuild_cgraph_edges",              /* name */
 275   NULL,                                 /* gate */
 276   rebuild_cgraph_edges,                 /* execute */
 277   NULL,                                 /* sub */
 278   NULL,                                 /* next */
 279   0,                                    /* static_pass_number */
 280   TV_NONE,                              /* tv_id */
 281   PROP_cfg,                             /* properties_required */
 282   0,                                    /* properties_provided */
 283   0,                                    /* properties_destroyed */
 284   0,                                    /* todo_flags_start */
 285   0,                                    /* todo_flags_finish */
 286  }
 287 };
 288
 289
 290 static unsigned int
 291 remove_cgraph_callee_edges (void)
 292 {
 293   cgraph_node_remove_callees (cgraph_node (current_function_decl));
 294   return 0;
 295 }
 296
 297 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 298 {
 299  {
 300   GIMPLE_PASS,
 301   "*remove_cgraph_callee_edges",                /* name */
 302   NULL,                                 /* gate */
 303   remove_cgraph_callee_edges,           /* execute */
 304   NULL,                                 /* sub */
 305   NULL,                                 /* next */
 306   0,                                    /* static_pass_number */
 307   TV_NONE,                              /* tv_id */
 308   0,                                    /* properties_required */
 309   0,                                    /* properties_provided */
 310   0,                                    /* properties_destroyed */
 311   0,                                    /* todo_flags_start */
 312   0,                                    /* todo_flags_finish */
 313  }
 314 };