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, and CLONE is a function whose
  76    body is to be set to a copy of FN, mapping argument declarations according
  77    to the ARG_MAP splay_tree.  */
  78
  79 static void
  80 clone_body (tree clone, tree fn, void *arg_map)
  81 {
  82   copy_body_data id;
  83
  84   /* Clone the body, as if we were making an inline call.  But, remap the
  85      parameters in the callee to the parameters of caller.  */
  86   memset (&id, 0, sizeof (id));
  87   id.src_fn = fn;
  88   id.dst_fn = clone;
  89   id.src_cfun = DECL_STRUCT_FUNCTION (fn);
  90   id.decl_map = (struct pointer_map_t *)arg_map;
  91
  92   id.copy_decl = copy_decl_no_change;
  93   id.transform_call_graph_edges = CB_CGE_DUPLICATE;
  94   id.transform_new_cfg = true;
  95   id.transform_return_to_modify = false;
  96   id.transform_lang_insert_block = insert_block;
  97
  98   /* We're not inside any EH region.  */
  99   id.eh_region = -1;
 100
 101   /* Actually copy the body.  */
 102   append_to_statement_list_force (copy_generic_body (&id),
 103                                   &DECL_SAVED_TREE (clone));
 104 }
 105
 106 /* FN is a function that has a complete body.  Clone the body as
 107    necessary.  Returns nonzero if there's no longer any need to
 108    process the main body.  */
 109
 110 bool
 111 maybe_clone_body (tree fn)
 112 {
 113   tree clone;
 114   bool first = true;
 115
 116   /* We only clone constructors and destructors.  */
 117   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
 118       && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
 119     return 0;
 120
 121   /* Emit the DWARF1 abstract instance.  */
 122   (*debug_hooks->deferred_inline_function) (fn);
 123
 124   /* We know that any clones immediately follow FN in the TYPE_METHODS
 125      list.  */
 126   push_to_top_level ();
 127   FOR_EACH_CLONE (clone, fn)
 128     {
 129       tree parm;
 130       tree clone_parm;
 131       int parmno;
 132       struct pointer_map_t *decl_map;
 133
 134       /* Update CLONE's source position information to match FN's.  */
 135       DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);
 136       DECL_INLINE (clone) = DECL_INLINE (fn);
 137       DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);
 138       DECL_COMDAT (clone) = DECL_COMDAT (fn);
 139       DECL_WEAK (clone) = DECL_WEAK (fn);
 140       DECL_ONE_ONLY (clone) = DECL_ONE_ONLY (fn);
 141       DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);
 142       DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);
 143       DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);
 144       DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);
 145       DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
 146       TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
 147       DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
 148       DECL_VISIBILITY_SPECIFIED (clone) = DECL_VISIBILITY_SPECIFIED (fn);
 149       DECL_DLLIMPORT_P (clone) = DECL_DLLIMPORT_P (fn);
 150
 151       /* Adjust the parameter names and locations.  */
 152       parm = DECL_ARGUMENTS (fn);
 153       clone_parm = DECL_ARGUMENTS (clone);
 154       /* Update the `this' parameter, which is always first.  */
 155       update_cloned_parm (parm, clone_parm, first);
 156       parm = TREE_CHAIN (parm);
 157       clone_parm = TREE_CHAIN (clone_parm);
 158       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 159         parm = TREE_CHAIN (parm);
 160       if (DECL_HAS_VTT_PARM_P (fn))
 161         parm = TREE_CHAIN (parm);
 162       if (DECL_HAS_VTT_PARM_P (clone))
 163         clone_parm = TREE_CHAIN (clone_parm);
 164       for (; parm;
 165            parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 166         /* Update this parameter.  */
 167         update_cloned_parm (parm, clone_parm, first);
 168
 169       /* Start processing the function.  */
 170       start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);
 171
 172       /* Remap the parameters.  */
 173       decl_map = pointer_map_create ();
 174       for (parmno = 0,
 175              parm = DECL_ARGUMENTS (fn),
 176              clone_parm = DECL_ARGUMENTS (clone);
 177            parm;
 178            ++parmno,
 179              parm = TREE_CHAIN (parm))
 180         {
 181           /* Map the in-charge parameter to an appropriate constant.  */
 182           if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)
 183             {
 184               tree in_charge;
 185               in_charge = in_charge_arg_for_name (DECL_NAME (clone));
 186               *pointer_map_insert (decl_map, parm) = in_charge;
 187             }
 188           else if (DECL_ARTIFICIAL (parm)
 189                    && DECL_NAME (parm) == vtt_parm_identifier)
 190             {
 191               /* For a subobject constructor or destructor, the next
 192                  argument is the VTT parameter.  Remap the VTT_PARM
 193                  from the CLONE to this parameter.  */
 194               if (DECL_HAS_VTT_PARM_P (clone))
 195                 {
 196                   DECL_ABSTRACT_ORIGIN (clone_parm) = parm;
 197                   *pointer_map_insert (decl_map, parm) = clone_parm;
 198                   clone_parm = TREE_CHAIN (clone_parm);
 199                 }
 200               /* Otherwise, map the VTT parameter to `NULL'.  */
 201               else
 202                 *pointer_map_insert (decl_map, parm) = null_pointer_node;
 203             }
 204           /* Map other parameters to their equivalents in the cloned
 205              function.  */
 206           else
 207             {
 208               *pointer_map_insert (decl_map, parm) = clone_parm;
 209               clone_parm = TREE_CHAIN (clone_parm);
 210             }
 211         }
 212
 213       if (targetm.cxx.cdtor_returns_this ())
 214         {
 215           parm = DECL_RESULT (fn);
 216           clone_parm = DECL_RESULT (clone);
 217           *pointer_map_insert (decl_map, parm) = clone_parm;
 218         }
 219       /* Clone the body.  */
 220       clone_body (clone, fn, decl_map);
 221
 222       /* Clean up.  */
 223       pointer_map_destroy (decl_map);
 224
 225       /* The clone can throw iff the original function can throw.  */
 226       cp_function_chain->can_throw = !TREE_NOTHROW (fn);
 227
 228       /* Now, expand this function into RTL, if appropriate.  */
 229       finish_function (0);
 230       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
 231       expand_or_defer_fn (clone);
 232       first = false;
 233     }
 234   pop_from_top_level ();
 235
 236   /* We don't need to process the original function any further.  */
 237   return 1;
 238 }