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 #include "ipa-utils.h"
  35
  36 /* Context of record_reference.  */
  37 struct record_reference_ctx
  38 {
  39   bool only_vars;
  40 };
  41
  42 /* Walk tree and record all calls and references to functions/variables.
  43    Called via walk_tree: TP is pointer to tree to be examined.
  44    When DATA is non-null, record references to callgraph.
  45    */
  46
  47 static tree
  48 record_reference (tree *tp, int *walk_subtrees, void *data)
  49 {
  50   tree t = *tp;
  51   tree decl;
  52   struct record_reference_ctx *ctx = (struct record_reference_ctx *)data;
  53
  54   switch (TREE_CODE (t))
  55     {
  56     case VAR_DECL:
  57     case FUNCTION_DECL:
  58       gcc_unreachable ();
  59       break;
  60
  61     case FDESC_EXPR:
  62     case ADDR_EXPR:
  63       /* Record dereferences to the functions.  This makes the
  64          functions reachable unconditionally.  */
  65       decl = get_base_var (*tp);
  66       if (TREE_CODE (decl) == FUNCTION_DECL && !ctx->only_vars)
  67         cgraph_mark_address_taken_node (cgraph_node (decl));
  68
  69       if (TREE_CODE (decl) == VAR_DECL)
  70         {
  71           gcc_assert (TREE_STATIC (decl) || DECL_EXTERNAL (decl));
  72           if (lang_hooks.callgraph.analyze_expr)
  73             lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
  74           varpool_mark_needed_node (varpool_node (decl));
  75         }
  76       *walk_subtrees = 0;
  77       break;
  78
  79     default:
  80       /* Save some cycles by not walking types and declaration as we
  81          won't find anything useful there anyway.  */
  82       if (IS_TYPE_OR_DECL_P (*tp))
  83         {
  84           *walk_subtrees = 0;
  85           break;
  86         }
  87
  88       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
  89         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
  90       break;
  91     }
  92
  93   return NULL_TREE;
  94 }
  95
  96 /* Reset inlining information of all incoming call edges of NODE.  */
  97
  98 void
  99 reset_inline_failed (struct cgraph_node *node)
 100 {
 101   struct cgraph_edge *e;
 102
 103   for (e = node->callers; e; e = e->next_caller)
 104     {
 105       e->callee->global.inlined_to = NULL;
 106       if (!node->analyzed)
 107         e->inline_failed = CIF_BODY_NOT_AVAILABLE;
 108       else if (node->local.redefined_extern_inline)
 109         e->inline_failed = CIF_REDEFINED_EXTERN_INLINE;
 110       else if (!node->local.inlinable)
 111         e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
 112       else if (e->call_stmt_cannot_inline_p)
 113         e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
 114       else
 115         e->inline_failed = CIF_FUNCTION_NOT_CONSIDERED;
 116     }
 117 }
 118
 119 /* Computes the frequency of the call statement so that it can be stored in
 120    cgraph_edge.  BB is the basic block of the call statement.  */
 121 int
 122 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 123 {
 124   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 125                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 126   int freq = bb->frequency;
 127
 128   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 129     return CGRAPH_FREQ_BASE;
 130
 131   if (!entry_freq)
 132     entry_freq = 1, freq++;
 133
 134   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 135   if (freq > CGRAPH_FREQ_MAX)
 136     freq = CGRAPH_FREQ_MAX;
 137
 138   return freq;
 139 }
 140
 141 /* Mark address taken in STMT.  */
 142
 143 static bool
 144 mark_address (gimple stmt ATTRIBUTE_UNUSED, tree addr,
 145               void *data ATTRIBUTE_UNUSED)
 146 {
 147   if (TREE_CODE (addr) == FUNCTION_DECL)
 148     {
 149       struct cgraph_node *node = cgraph_node (addr);
 150       cgraph_mark_address_taken_node (node);
 151     }
 152   else
 153     {
 154       addr = get_base_address (addr);
 155       if (addr && TREE_CODE (addr) == VAR_DECL
 156           && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 157         {
 158           struct varpool_node *vnode = varpool_node (addr);
 159           int walk_subtrees;
 160
 161           if (lang_hooks.callgraph.analyze_expr)
 162             lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 163           varpool_mark_needed_node (vnode);
 164         }
 165     }
 166
 167   return false;
 168 }
 169
 170 /* Mark load of T.  */
 171
 172 static bool
 173 mark_load (gimple stmt ATTRIBUTE_UNUSED, tree t,
 174            void *data ATTRIBUTE_UNUSED)
 175 {
 176   t = get_base_address (t);
 177   if (TREE_CODE (t) == VAR_DECL
 178       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 179     {
 180       struct varpool_node *vnode = varpool_node (t);
 181       int walk_subtrees;
 182
 183       if (lang_hooks.callgraph.analyze_expr)
 184         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 185       varpool_mark_needed_node (vnode);
 186     }
 187   return false;
 188 }
 189
 190 /* Mark store of T.  */
 191
 192 static bool
 193 mark_store (gimple stmt ATTRIBUTE_UNUSED, tree t,
 194             void *data ATTRIBUTE_UNUSED)
 195 {
 196   t = get_base_address (t);
 197   if (TREE_CODE (t) == VAR_DECL
 198       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 199     {
 200       struct varpool_node *vnode = varpool_node (t);
 201       int walk_subtrees;
 202
 203       if (lang_hooks.callgraph.analyze_expr)
 204         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 205       varpool_mark_needed_node (vnode);
 206      }
 207   return false;
 208 }
 209
 210 /* Create cgraph edges for function calls.
 211    Also look for functions and variables having addresses taken.  */
 212
 213 static unsigned int
 214 build_cgraph_edges (void)
 215 {
 216   basic_block bb;
 217   struct cgraph_node *node = cgraph_node (current_function_decl);
 218   struct pointer_set_t *visited_nodes = pointer_set_create ();
 219   gimple_stmt_iterator gsi;
 220   tree step;
 221
 222   /* Create the callgraph edges and record the nodes referenced by the function.
 223      body.  */
 224   FOR_EACH_BB (bb)
 225     {
 226       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 227         {
 228           gimple stmt = gsi_stmt (gsi);
 229           tree decl;
 230
 231           if (is_gimple_call (stmt) && (decl = gimple_call_fndecl (stmt)))
 232             cgraph_create_edge (node, cgraph_node (decl), stmt,
 233                                 bb->count,
 234                                 compute_call_stmt_bb_frequency
 235                                   (current_function_decl, bb),
 236                                 bb->loop_depth);
 237           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 238                                          mark_store, mark_address);
 239           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 240               && gimple_omp_parallel_child_fn (stmt))
 241             {
 242               tree fn = gimple_omp_parallel_child_fn (stmt);
 243               cgraph_mark_needed_node (cgraph_node (fn));
 244             }
 245           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 246             {
 247               tree fn = gimple_omp_task_child_fn (stmt);
 248               if (fn)
 249                 cgraph_mark_needed_node (cgraph_node (fn));
 250               fn = gimple_omp_task_copy_fn (stmt);
 251               if (fn)
 252                 cgraph_mark_needed_node (cgraph_node (fn));
 253             }
 254         }
 255       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 256         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 257                                        mark_load, mark_store, mark_address);
 258    }
 259
 260   /* Look for initializers of constant variables and private statics.  */
 261   for (step = cfun->local_decls;
 262        step;
 263        step = TREE_CHAIN (step))
 264     {
 265       tree decl = TREE_VALUE (step);
 266       if (TREE_CODE (decl) == VAR_DECL
 267           && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 268         varpool_finalize_decl (decl);
 269     }
 270
 271   pointer_set_destroy (visited_nodes);
 272   return 0;
 273 }
 274
 275 struct gimple_opt_pass pass_build_cgraph_edges =
 276 {
 277  {
 278   GIMPLE_PASS,
 279   "*build_cgraph_edges",                        /* name */
 280   NULL,                                 /* gate */
 281   build_cgraph_edges,                   /* execute */
 282   NULL,                                 /* sub */
 283   NULL,                                 /* next */
 284   0,                                    /* static_pass_number */
 285   TV_NONE,                              /* tv_id */
 286   PROP_cfg,                             /* properties_required */
 287   0,                                    /* properties_provided */
 288   0,                                    /* properties_destroyed */
 289   0,                                    /* todo_flags_start */
 290   0                                     /* todo_flags_finish */
 291  }
 292 };
 293
 294 /* Record references to functions and other variables present in the
 295    initial value of DECL, a variable.
 296    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 297
 298 void
 299 record_references_in_initializer (tree decl, bool only_vars)
 300 {
 301   struct pointer_set_t *visited_nodes = pointer_set_create ();
 302   struct record_reference_ctx ctx = {false};
 303
 304   ctx.only_vars = only_vars;
 305   walk_tree (&DECL_INITIAL (decl), record_reference,
 306              &ctx, visited_nodes);
 307   pointer_set_destroy (visited_nodes);
 308 }
 309
 310 /* Rebuild cgraph edges for current function node.  This needs to be run after
 311    passes that don't update the cgraph.  */
 312
 313 unsigned int
 314 rebuild_cgraph_edges (void)
 315 {
 316   basic_block bb;
 317   struct cgraph_node *node = cgraph_node (current_function_decl);
 318   gimple_stmt_iterator gsi;
 319
 320   cgraph_node_remove_callees (node);
 321
 322   node->count = ENTRY_BLOCK_PTR->count;
 323
 324   FOR_EACH_BB (bb)
 325     {
 326       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 327         {
 328           gimple stmt = gsi_stmt (gsi);
 329           tree decl;
 330
 331           if (is_gimple_call (stmt) && (decl = gimple_call_fndecl (stmt)))
 332             cgraph_create_edge (node, cgraph_node (decl), stmt,
 333                                 bb->count,
 334                                 compute_call_stmt_bb_frequency
 335                                   (current_function_decl, bb),
 336                                 bb->loop_depth);
 337           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 338                                          mark_store, mark_address);
 339
 340         }
 341       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 342         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 343                                        mark_load, mark_store, mark_address);
 344     }
 345   gcc_assert (!node->global.inlined_to);
 346
 347   return 0;
 348 }
 349
 350 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 351 {
 352  {
 353   GIMPLE_PASS,
 354   "*rebuild_cgraph_edges",              /* name */
 355   NULL,                                 /* gate */
 356   rebuild_cgraph_edges,                 /* execute */
 357   NULL,                                 /* sub */
 358   NULL,                                 /* next */
 359   0,                                    /* static_pass_number */
 360   TV_NONE,                              /* tv_id */
 361   PROP_cfg,                             /* properties_required */
 362   0,                                    /* properties_provided */
 363   0,                                    /* properties_destroyed */
 364   0,                                    /* todo_flags_start */
 365   0,                                    /* todo_flags_finish */
 366  }
 367 };
 368
 369
 370 static unsigned int
 371 remove_cgraph_callee_edges (void)
 372 {
 373   cgraph_node_remove_callees (cgraph_node (current_function_decl));
 374   return 0;
 375 }
 376
 377 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 378 {
 379  {
 380   GIMPLE_PASS,
 381   "*remove_cgraph_callee_edges",                /* name */
 382   NULL,                                 /* gate */
 383   remove_cgraph_callee_edges,           /* execute */
 384   NULL,                                 /* sub */
 385   NULL,                                 /* next */
 386   0,                                    /* static_pass_number */
 387   TV_NONE,                              /* tv_id */
 388   0,                                    /* properties_required */
 389   0,                                    /* properties_provided */
 390   0,                                    /* properties_destroyed */
 391   0,                                    /* todo_flags_start */
 392   0,                                    /* todo_flags_finish */
 393  }
 394 };