gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005
   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, 51 Franklin Street, Fifth Floor, Boston, MA
  21 02110-1301, 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 "target.h"
  38 #include "debug.h"
  39 #include "tree-inline.h"
  40 #include "flags.h"
  41 #include "langhooks.h"
  42 #include "diagnostic.h"
  43 #include "tree-dump.h"
  44 #include "tree-gimple.h"
  45
  46 /* Prototypes.  */
  47
  48 static void update_cloned_parm (tree, tree, bool);
  49
  50 /* CLONED_PARM is a copy of CLONE, generated for a cloned constructor
  51    or destructor.  Update it to ensure that the source-position for
  52    the cloned parameter matches that for the original, and that the
  53    debugging generation code will be able to find the original PARM.  */
  54
  55 static void
  56 update_cloned_parm (tree parm, tree cloned_parm, bool first)
  57 {
  58   DECL_ABSTRACT_ORIGIN (cloned_parm) = parm;
  59
  60   /* We may have taken its address.  */
  61   TREE_ADDRESSABLE (cloned_parm) = TREE_ADDRESSABLE (parm);
  62
  63   /* The definition might have different constness.  */
  64   TREE_READONLY (cloned_parm) = TREE_READONLY (parm);
  65
  66   TREE_USED (cloned_parm) = !first || TREE_USED (parm);
  67
  68   /* The name may have changed from the declaration.  */
  69   DECL_NAME (cloned_parm) = DECL_NAME (parm);
  70   DECL_SOURCE_LOCATION (cloned_parm) = DECL_SOURCE_LOCATION (parm);
  71   TREE_TYPE (cloned_parm) = TREE_TYPE (parm);
  72
  73   DECL_GIMPLE_REG_P (cloned_parm) = DECL_GIMPLE_REG_P (parm);
  74 }
  75
  76 /* FN is a function that has a complete body.  Clone the body as
  77    necessary.  Returns nonzero if there's no longer any need to
  78    process the main body.  */
  79
  80 bool
  81 maybe_clone_body (tree fn)
  82 {
  83   tree clone;
  84   bool first = true;
  85
  86   /* We only clone constructors and destructors.  */
  87   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
  88       && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
  89     return 0;
  90
  91   /* Emit the DWARF1 abstract instance.  */
  92   (*debug_hooks->deferred_inline_function) (fn);
  93
  94   /* We know that any clones immediately follow FN in the TYPE_METHODS
  95      list.  */
  96   push_to_top_level ();
  97   FOR_EACH_CLONE (clone, fn)
  98     {
  99       tree parm;
 100       tree clone_parm;
 101       int parmno;
 102       splay_tree decl_map;
 103
 104       /* Update CLONE's source position information to match FN's.  */
 105       DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);
 106       DECL_INLINE (clone) = DECL_INLINE (fn);
 107       DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);
 108       DECL_COMDAT (clone) = DECL_COMDAT (fn);
 109       DECL_WEAK (clone) = DECL_WEAK (fn);
 110       DECL_ONE_ONLY (clone) = DECL_ONE_ONLY (fn);
 111       DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);
 112       DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);
 113       DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);
 114       DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);
 115       DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
 116       TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
 117       DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
 118       DECL_VISIBILITY_SPECIFIED (clone) = DECL_VISIBILITY_SPECIFIED (fn);
 119
 120       /* Adjust the parameter names and locations.  */
 121       parm = DECL_ARGUMENTS (fn);
 122       clone_parm = DECL_ARGUMENTS (clone);
 123       /* Update the `this' parameter, which is always first.  */
 124       update_cloned_parm (parm, clone_parm, first);
 125       parm = TREE_CHAIN (parm);
 126       clone_parm = TREE_CHAIN (clone_parm);
 127       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 128         parm = TREE_CHAIN (parm);
 129       if (DECL_HAS_VTT_PARM_P (fn))
 130         parm = TREE_CHAIN (parm);
 131       if (DECL_HAS_VTT_PARM_P (clone))
 132         clone_parm = TREE_CHAIN (clone_parm);
 133       for (; parm;
 134            parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 135         /* Update this parameter.  */
 136         update_cloned_parm (parm, clone_parm, first);
 137
 138       /* Start processing the function.  */
 139       start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);
 140
 141       /* Remap the parameters.  */
 142       decl_map = splay_tree_new (splay_tree_compare_pointers, NULL, NULL);
 143       for (parmno = 0,
 144              parm = DECL_ARGUMENTS (fn),
 145              clone_parm = DECL_ARGUMENTS (clone);
 146            parm;
 147            ++parmno,
 148              parm = TREE_CHAIN (parm))
 149         {
 150           /* Map the in-charge parameter to an appropriate constant.  */
 151           if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)
 152             {
 153               tree in_charge;
 154               in_charge = in_charge_arg_for_name (DECL_NAME (clone));
 155               splay_tree_insert (decl_map,
 156                                  (splay_tree_key) parm,
 157                                  (splay_tree_value) in_charge);
 158             }
 159           else if (DECL_ARTIFICIAL (parm)
 160                    && DECL_NAME (parm) == vtt_parm_identifier)
 161             {
 162               /* For a subobject constructor or destructor, the next
 163                  argument is the VTT parameter.  Remap the VTT_PARM
 164                  from the CLONE to this parameter.  */
 165               if (DECL_HAS_VTT_PARM_P (clone))
 166                 {
 167                   DECL_ABSTRACT_ORIGIN (clone_parm) = parm;
 168                   splay_tree_insert (decl_map,
 169                                      (splay_tree_key) parm,
 170                                      (splay_tree_value) clone_parm);
 171                   clone_parm = TREE_CHAIN (clone_parm);
 172                 }
 173               /* Otherwise, map the VTT parameter to `NULL'.  */
 174               else
 175                 {
 176                   splay_tree_insert (decl_map,
 177                                      (splay_tree_key) parm,
 178                                      (splay_tree_value) null_pointer_node);
 179                 }
 180             }
 181           /* Map other parameters to their equivalents in the cloned
 182              function.  */
 183           else
 184             {
 185               splay_tree_insert (decl_map,
 186                                  (splay_tree_key) parm,
 187                                  (splay_tree_value) clone_parm);
 188               clone_parm = TREE_CHAIN (clone_parm);
 189             }
 190         }
 191
 192       if (targetm.cxx.cdtor_returns_this ())
 193         {
 194           parm = DECL_RESULT (fn);
 195           clone_parm = DECL_RESULT (clone);
 196           splay_tree_insert (decl_map, (splay_tree_key) parm,
 197                              (splay_tree_value) clone_parm);
 198         }
 199       /* Clone the body.  */
 200       clone_body (clone, fn, decl_map);
 201
 202       /* Clean up.  */
 203       splay_tree_delete (decl_map);
 204
 205       /* The clone can throw iff the original function can throw.  */
 206       cp_function_chain->can_throw = !TREE_NOTHROW (fn);
 207
 208       /* Now, expand this function into RTL, if appropriate.  */
 209       finish_function (0);
 210       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
 211       expand_or_defer_fn (clone);
 212       first = false;
 213     }
 214   pop_from_top_level ();
 215
 216   /* We don't need to process the original function any further.  */
 217   return 1;
 218 }