gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007
   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 3, 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 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 "cp-tree.h"
  28 #include "rtl.h"
  29 #include "insn-config.h"
  30 #include "input.h"
  31 #include "integrate.h"
  32 #include "toplev.h"
  33 #include "varray.h"
  34 #include "params.h"
  35 #include "hashtab.h"
  36 #include "target.h"
  37 #include "debug.h"
  38 #include "tree-inline.h"
  39 #include "flags.h"
  40 #include "langhooks.h"
  41 #include "diagnostic.h"
  42 #include "tree-dump.h"
  43 #include "tree-gimple.h"
  44
  45 /* Prototypes.  */
  46
  47 static void update_cloned_parm (tree, tree, bool);
  48
  49 /* CLONED_PARM is a copy of CLONE, generated for a cloned constructor
  50    or destructor.  Update it to ensure that the source-position for
  51    the cloned parameter matches that for the original, and that the
  52    debugging generation code will be able to find the original PARM.  */
  53
  54 static void
  55 update_cloned_parm (tree parm, tree cloned_parm, bool first)
  56 {
  57   DECL_ABSTRACT_ORIGIN (cloned_parm) = parm;
  58
  59   /* We may have taken its address.  */
  60   TREE_ADDRESSABLE (cloned_parm) = TREE_ADDRESSABLE (parm);
  61
  62   /* The definition might have different constness.  */
  63   TREE_READONLY (cloned_parm) = TREE_READONLY (parm);
  64
  65   TREE_USED (cloned_parm) = !first || TREE_USED (parm);
  66
  67   /* The name may have changed from the declaration.  */
  68   DECL_NAME (cloned_parm) = DECL_NAME (parm);
  69   DECL_SOURCE_LOCATION (cloned_parm) = DECL_SOURCE_LOCATION (parm);
  70   TREE_TYPE (cloned_parm) = TREE_TYPE (parm);
  71
  72   DECL_GIMPLE_REG_P (cloned_parm) = DECL_GIMPLE_REG_P (parm);
  73 }
  74
  75 /* FN is a function that has a complete body.  Clone the body as
  76    necessary.  Returns nonzero if there's no longer any need to
  77    process the main body.  */
  78
  79 bool
  80 maybe_clone_body (tree fn)
  81 {
  82   tree clone;
  83   bool first = true;
  84
  85   /* We only clone constructors and destructors.  */
  86   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
  87       && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
  88     return 0;
  89
  90   /* Emit the DWARF1 abstract instance.  */
  91   (*debug_hooks->deferred_inline_function) (fn);
  92
  93   /* We know that any clones immediately follow FN in the TYPE_METHODS
  94      list.  */
  95   push_to_top_level ();
  96   FOR_EACH_CLONE (clone, fn)
  97     {
  98       tree parm;
  99       tree clone_parm;
 100       int parmno;
 101       struct pointer_map_t *decl_map;
 102
 103       /* Update CLONE's source position information to match FN's.  */
 104       DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);
 105       DECL_INLINE (clone) = DECL_INLINE (fn);
 106       DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);
 107       DECL_COMDAT (clone) = DECL_COMDAT (fn);
 108       DECL_WEAK (clone) = DECL_WEAK (fn);
 109       DECL_ONE_ONLY (clone) = DECL_ONE_ONLY (fn);
 110       DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);
 111       DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);
 112       DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);
 113       DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);
 114       DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
 115       TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
 116       DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
 117       DECL_VISIBILITY_SPECIFIED (clone) = DECL_VISIBILITY_SPECIFIED (fn);
 118
 119       /* Adjust the parameter names and locations.  */
 120       parm = DECL_ARGUMENTS (fn);
 121       clone_parm = DECL_ARGUMENTS (clone);
 122       /* Update the `this' parameter, which is always first.  */
 123       update_cloned_parm (parm, clone_parm, first);
 124       parm = TREE_CHAIN (parm);
 125       clone_parm = TREE_CHAIN (clone_parm);
 126       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 127         parm = TREE_CHAIN (parm);
 128       if (DECL_HAS_VTT_PARM_P (fn))
 129         parm = TREE_CHAIN (parm);
 130       if (DECL_HAS_VTT_PARM_P (clone))
 131         clone_parm = TREE_CHAIN (clone_parm);
 132       for (; parm;
 133            parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 134         /* Update this parameter.  */
 135         update_cloned_parm (parm, clone_parm, first);
 136
 137       /* Start processing the function.  */
 138       start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);
 139
 140       /* Remap the parameters.  */
 141       decl_map = pointer_map_create ();
 142       for (parmno = 0,
 143              parm = DECL_ARGUMENTS (fn),
 144              clone_parm = DECL_ARGUMENTS (clone);
 145            parm;
 146            ++parmno,
 147              parm = TREE_CHAIN (parm))
 148         {
 149           /* Map the in-charge parameter to an appropriate constant.  */
 150           if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)
 151             {
 152               tree in_charge;
 153               in_charge = in_charge_arg_for_name (DECL_NAME (clone));
 154               *pointer_map_insert (decl_map, parm) = in_charge;
 155             }
 156           else if (DECL_ARTIFICIAL (parm)
 157                    && DECL_NAME (parm) == vtt_parm_identifier)
 158             {
 159               /* For a subobject constructor or destructor, the next
 160                  argument is the VTT parameter.  Remap the VTT_PARM
 161                  from the CLONE to this parameter.  */
 162               if (DECL_HAS_VTT_PARM_P (clone))
 163                 {
 164                   DECL_ABSTRACT_ORIGIN (clone_parm) = parm;
 165                   *pointer_map_insert (decl_map, parm) = clone_parm;
 166                   clone_parm = TREE_CHAIN (clone_parm);
 167                 }
 168               /* Otherwise, map the VTT parameter to `NULL'.  */
 169               else
 170                 *pointer_map_insert (decl_map, parm) = null_pointer_node;
 171             }
 172           /* Map other parameters to their equivalents in the cloned
 173              function.  */
 174           else
 175             {
 176               *pointer_map_insert (decl_map, parm) = clone_parm;
 177               clone_parm = TREE_CHAIN (clone_parm);
 178             }
 179         }
 180
 181       if (targetm.cxx.cdtor_returns_this ())
 182         {
 183           parm = DECL_RESULT (fn);
 184           clone_parm = DECL_RESULT (clone);
 185           *pointer_map_insert (decl_map, parm) = clone_parm;
 186         }
 187       /* Clone the body.  */
 188       clone_body (clone, fn, decl_map);
 189
 190       /* Clean up.  */
 191       pointer_map_destroy (decl_map);
 192
 193       /* The clone can throw iff the original function can throw.  */
 194       cp_function_chain->can_throw = !TREE_NOTHROW (fn);
 195
 196       /* Now, expand this function into RTL, if appropriate.  */
 197       finish_function (0);
 198       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
 199       expand_or_defer_fn (clone);
 200       first = false;
 201     }
 202   pop_from_top_level ();
 203
 204   /* We don't need to process the original function any further.  */
 205   return 1;
 206 }