toolchain/gcc/gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004
   3    Free Software Foundation, Inc.
   4    Written by Mark Michell (mark@codesourcery.com).
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it
   9 under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21 02111-1307, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "tree.h"
  28 #include "cp-tree.h"
  29 #include "rtl.h"
  30 #include "insn-config.h"
  31 #include "input.h"
  32 #include "integrate.h"
  33 #include "toplev.h"
  34 #include "varray.h"
  35 #include "params.h"
  36 #include "hashtab.h"
  37 #include "debug.h"
  38 #include "tree-inline.h"
  39
  40 /* Prototypes.  */
  41
  42 static tree calls_setjmp_r (tree *, int *, void *);
  43 static void update_cloned_parm (tree, tree);
  44 static void dump_function (enum tree_dump_index, tree);
  45
  46 /* Optimize the body of FN.  */
  47
  48 void
  49 optimize_function (tree fn)
  50 {
  51   dump_function (TDI_original, fn);
  52
  53   if (flag_inline_trees
  54       /* We do not inline thunks, as (a) the backend tries to optimize
  55          the call to the thunkee, (b) tree based inlining breaks that
  56          optimization, (c) virtual functions are rarely inlineable,
  57          and (d) TARGET_ASM_OUTPUT_MI_THUNK is there to DTRT anyway.  */
  58       && !DECL_THUNK_P (fn))
  59     {
  60       optimize_inline_calls (fn);
  61       dump_function (TDI_inlined, fn);
  62     }
  63
  64   dump_function (TDI_optimized, fn);
  65 }
  66
  67 /* Called from calls_setjmp_p via walk_tree.  */
  68
  69 static tree
  70 calls_setjmp_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
  71                 void *data ATTRIBUTE_UNUSED)
  72 {
  73   /* We're only interested in FUNCTION_DECLS.  */
  74   if (TREE_CODE (*tp) != FUNCTION_DECL)
  75     return NULL_TREE;
  76
  77   return setjmp_call_p (*tp) ? *tp : NULL_TREE;
  78 }
  79
  80 /* Returns nonzero if FN calls `setjmp' or some other function that
  81    can return more than once.  This function is conservative; it may
  82    occasionally return a nonzero value even when FN does not actually
  83    call `setjmp'.  */
  84
  85 bool
  86 calls_setjmp_p (tree fn)
  87 {
  88   return walk_tree_without_duplicates (&DECL_SAVED_TREE (fn),
  89                                        calls_setjmp_r,
  90                                        NULL) != NULL_TREE;
  91 }
  92
  93 /* CLONED_PARM is a copy of CLONE, generated for a cloned constructor
  94    or destructor.  Update it to ensure that the source-position for
  95    the cloned parameter matches that for the original, and that the
  96    debugging generation code will be able to find the original PARM.  */
  97
  98 static void
  99 update_cloned_parm (tree parm, tree cloned_parm)
 100 {
 101   DECL_ABSTRACT_ORIGIN (cloned_parm) = parm;
 102
 103   /* We may have taken its address.  */
 104   TREE_ADDRESSABLE (cloned_parm) = TREE_ADDRESSABLE (parm);
 105
 106   /* The definition might have different constness.  */
 107   TREE_READONLY (cloned_parm) = TREE_READONLY (parm);
 108
 109   TREE_USED (cloned_parm) = TREE_USED (parm);
 110
 111   /* The name may have changed from the declaration.  */
 112   DECL_NAME (cloned_parm) = DECL_NAME (parm);
 113   DECL_SOURCE_LOCATION (cloned_parm) = DECL_SOURCE_LOCATION (parm);
 114 }
 115
 116 /* FN is a function that has a complete body.  Clone the body as
 117    necessary.  Returns nonzero if there's no longer any need to
 118    process the main body.  */
 119
 120 bool
 121 maybe_clone_body (tree fn)
 122 {
 123   tree clone;
 124
 125   /* We only clone constructors and destructors.  */
 126   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
 127       && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
 128     return 0;
 129
 130   /* Emit the DWARF1 abstract instance.  */
 131   (*debug_hooks->deferred_inline_function) (fn);
 132
 133   /* We know that any clones immediately follow FN in the TYPE_METHODS
 134      list.  */
 135   for (clone = TREE_CHAIN (fn);
 136        clone && DECL_CLONED_FUNCTION_P (clone);
 137        clone = TREE_CHAIN (clone))
 138     {
 139       tree parm;
 140       tree clone_parm;
 141       int parmno;
 142       splay_tree decl_map;
 143
 144       /* Update CLONE's source position information to match FN's.  */
 145       DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);
 146       DECL_INLINE (clone) = DECL_INLINE (fn);
 147       DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);
 148       DECL_COMDAT (clone) = DECL_COMDAT (fn);
 149       DECL_WEAK (clone) = DECL_WEAK (fn);
 150       DECL_ONE_ONLY (clone) = DECL_ONE_ONLY (fn);
 151       DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);
 152       DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);
 153       DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);
 154       DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);
 155       DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
 156       TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
 157       DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
 158
 159       /* Adjust the parameter names and locations.  */
 160       parm = DECL_ARGUMENTS (fn);
 161       clone_parm = DECL_ARGUMENTS (clone);
 162       /* Update the `this' parameter, which is always first.  */
 163       update_cloned_parm (parm, clone_parm);
 164       parm = TREE_CHAIN (parm);
 165       clone_parm = TREE_CHAIN (clone_parm);
 166       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 167         parm = TREE_CHAIN (parm);
 168       if (DECL_HAS_VTT_PARM_P (fn))
 169         parm = TREE_CHAIN (parm);
 170       if (DECL_HAS_VTT_PARM_P (clone))
 171         clone_parm = TREE_CHAIN (clone_parm);
 172       for (; parm;
 173            parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 174         /* Update this parameter.  */
 175         update_cloned_parm (parm, clone_parm);
 176
 177       /* Start processing the function.  */
 178       push_to_top_level ();
 179       start_function (NULL_TREE, clone, NULL_TREE, SF_PRE_PARSED);
 180
 181       /* Remap the parameters.  */
 182       decl_map = splay_tree_new (splay_tree_compare_pointers, NULL, NULL);
 183       for (parmno = 0,
 184              parm = DECL_ARGUMENTS (fn),
 185              clone_parm = DECL_ARGUMENTS (clone);
 186            parm;
 187            ++parmno,
 188              parm = TREE_CHAIN (parm))
 189         {
 190           /* Map the in-charge parameter to an appropriate constant.  */
 191           if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)
 192             {
 193               tree in_charge;
 194               in_charge = in_charge_arg_for_name (DECL_NAME (clone));
 195               splay_tree_insert (decl_map,
 196                                  (splay_tree_key) parm,
 197                                  (splay_tree_value) in_charge);
 198             }
 199           else if (DECL_ARTIFICIAL (parm)
 200                    && DECL_NAME (parm) == vtt_parm_identifier)
 201             {
 202               /* For a subobject constructor or destructor, the next
 203                  argument is the VTT parameter.  Remap the VTT_PARM
 204                  from the CLONE to this parameter.  */
 205               if (DECL_HAS_VTT_PARM_P (clone))
 206                 {
 207                   DECL_ABSTRACT_ORIGIN (clone_parm) = parm;
 208                   splay_tree_insert (decl_map,
 209                                      (splay_tree_key) parm,
 210                                      (splay_tree_value) clone_parm);
 211                   clone_parm = TREE_CHAIN (clone_parm);
 212                 }
 213               /* Otherwise, map the VTT parameter to `NULL'.  */
 214               else
 215                 {
 216                   splay_tree_insert (decl_map,
 217                                      (splay_tree_key) parm,
 218                                      (splay_tree_value) null_pointer_node);
 219                 }
 220             }
 221           /* Map other parameters to their equivalents in the cloned
 222              function.  */
 223           else
 224             {
 225               splay_tree_insert (decl_map,
 226                                  (splay_tree_key) parm,
 227                                  (splay_tree_value) clone_parm);
 228               clone_parm = TREE_CHAIN (clone_parm);
 229             }
 230         }
 231
 232       /* Clone the body.  */
 233       clone_body (clone, fn, decl_map);
 234
 235       /* Clean up.  */
 236       splay_tree_delete (decl_map);
 237
 238       /* The clone can throw iff the original function can throw.  */
 239       cp_function_chain->can_throw = !TREE_NOTHROW (fn);
 240
 241       /* Now, expand this function into RTL, if appropriate.  */
 242       finish_function (0);
 243       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
 244       expand_or_defer_fn (clone);
 245       pop_from_top_level ();
 246     }
 247
 248   /* We don't need to process the original function any further.  */
 249   return 1;
 250 }
 251
 252 /* Dump FUNCTION_DECL FN as tree dump PHASE.  */
 253
 254 static void
 255 dump_function (enum tree_dump_index phase, tree fn)
 256 {
 257   FILE *stream;
 258   int flags;
 259
 260   stream = dump_begin (phase, &flags);
 261   if (stream)
 262     {
 263       fprintf (stream, "\n;; Function %s",
 264                decl_as_string (fn, TFF_DECL_SPECIFIERS));
 265       fprintf (stream, " (%s)\n",
 266                decl_as_string (DECL_ASSEMBLER_NAME (fn), 0));
 267       fprintf (stream, ";; enabled by -fdump-%s\n", dump_flag_name (phase));
 268       fprintf (stream, "\n");
 269
 270       dump_node (fn, TDF_SLIM | flags, stream);
 271       dump_end (phase, stream);
 272     }
 273 }