gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007, 2008
   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 "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
  76 /* FN is a function in High GIMPLE form that has a complete body and no
  77    CFG.  CLONE is a function whose body is to be set to a copy of FN,
  78    mapping argument declarations according to the ARG_MAP splay_tree.  */
  79
  80 static void
  81 clone_body (tree clone, tree fn, void *arg_map)
  82 {
  83   copy_body_data id;
  84   gimple_seq new_body;
  85
  86   /* FN must already be in GIMPLE form.  */
  87   gcc_assert (gimple_body (fn));
  88
  89   /* Clone the body, as if we were making an inline call.  But, remap
  90      the parameters in the callee to the parameters of caller.  */
  91   memset (&id, 0, sizeof (id));
  92   id.src_fn = fn;
  93   id.dst_fn = clone;
  94   id.src_cfun = DECL_STRUCT_FUNCTION (fn);
  95   id.decl_map = (struct pointer_map_t *) arg_map;
  96
  97   id.copy_decl = copy_decl_no_change;
  98   id.transform_call_graph_edges = CB_CGE_DUPLICATE;
  99   id.transform_new_cfg = true;
 100   id.transform_return_to_modify = false;
 101   id.transform_lang_insert_block = NULL;
 102
 103   /* We're not inside any EH region.  */
 104   id.eh_region = -1;
 105
 106   /* Actually copy the body.  */
 107   new_body = remap_gimple_seq (gimple_body (fn), &id);
 108   gimple_set_body (clone, new_body);
 109 }
 110
 111 /* FN is a function that has a complete body.  Clone the body as
 112    necessary.  Returns nonzero if there's no longer any need to
 113    process the main body.  */
 114
 115 bool
 116 maybe_clone_body (tree fn)
 117 {
 118   tree clone;
 119   bool first = true;
 120
 121   /* We only clone constructors and destructors.  */
 122   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
 123       && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
 124     return 0;
 125
 126   /* Emit the DWARF1 abstract instance.  */
 127   (*debug_hooks->deferred_inline_function) (fn);
 128
 129   /* We know that any clones immediately follow FN in the TYPE_METHODS
 130      list.  */
 131   push_to_top_level ();
 132   FOR_EACH_CLONE (clone, fn)
 133     {
 134       tree parm;
 135       tree clone_parm;
 136       int parmno;
 137       struct pointer_map_t *decl_map;
 138
 139       /* Update CLONE's source position information to match FN's.  */
 140       DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);
 141       DECL_INLINE (clone) = DECL_INLINE (fn);
 142       DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);
 143       DECL_COMDAT (clone) = DECL_COMDAT (fn);
 144       DECL_WEAK (clone) = DECL_WEAK (fn);
 145       DECL_ONE_ONLY (clone) = DECL_ONE_ONLY (fn);
 146       DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);
 147       DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);
 148       DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);
 149       DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);
 150       DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
 151       TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
 152       DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
 153       DECL_VISIBILITY_SPECIFIED (clone) = DECL_VISIBILITY_SPECIFIED (fn);
 154       DECL_DLLIMPORT_P (clone) = DECL_DLLIMPORT_P (fn);
 155
 156       /* Adjust the parameter names and locations.  */
 157       parm = DECL_ARGUMENTS (fn);
 158       clone_parm = DECL_ARGUMENTS (clone);
 159       /* Update the `this' parameter, which is always first.  */
 160       update_cloned_parm (parm, clone_parm, first);
 161       parm = TREE_CHAIN (parm);
 162       clone_parm = TREE_CHAIN (clone_parm);
 163       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 164         parm = TREE_CHAIN (parm);
 165       if (DECL_HAS_VTT_PARM_P (fn))
 166         parm = TREE_CHAIN (parm);
 167       if (DECL_HAS_VTT_PARM_P (clone))
 168         clone_parm = TREE_CHAIN (clone_parm);
 169       for (; parm;
 170            parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 171         /* Update this parameter.  */
 172         update_cloned_parm (parm, clone_parm, first);
 173
 174       /* Start processing the function.  */
 175       start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);
 176
 177       /* Remap the parameters.  */
 178       decl_map = pointer_map_create ();
 179       for (parmno = 0,
 180              parm = DECL_ARGUMENTS (fn),
 181              clone_parm = DECL_ARGUMENTS (clone);
 182            parm;
 183            ++parmno,
 184              parm = TREE_CHAIN (parm))
 185         {
 186           /* Map the in-charge parameter to an appropriate constant.  */
 187           if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)
 188             {
 189               tree in_charge;
 190               in_charge = in_charge_arg_for_name (DECL_NAME (clone));
 191               *pointer_map_insert (decl_map, parm) = in_charge;
 192             }
 193           else if (DECL_ARTIFICIAL (parm)
 194                    && DECL_NAME (parm) == vtt_parm_identifier)
 195             {
 196               /* For a subobject constructor or destructor, the next
 197                  argument is the VTT parameter.  Remap the VTT_PARM
 198                  from the CLONE to this parameter.  */
 199               if (DECL_HAS_VTT_PARM_P (clone))
 200                 {
 201                   DECL_ABSTRACT_ORIGIN (clone_parm) = parm;
 202                   *pointer_map_insert (decl_map, parm) = clone_parm;
 203                   clone_parm = TREE_CHAIN (clone_parm);
 204                 }
 205               /* Otherwise, map the VTT parameter to `NULL'.  */
 206               else
 207                 *pointer_map_insert (decl_map, parm) = null_pointer_node;
 208             }
 209           /* Map other parameters to their equivalents in the cloned
 210              function.  */
 211           else
 212             {
 213               *pointer_map_insert (decl_map, parm) = clone_parm;
 214               clone_parm = TREE_CHAIN (clone_parm);
 215             }
 216         }
 217
 218       if (targetm.cxx.cdtor_returns_this ())
 219         {
 220           parm = DECL_RESULT (fn);
 221           clone_parm = DECL_RESULT (clone);
 222           *pointer_map_insert (decl_map, parm) = clone_parm;
 223         }
 224       /* Clone the body.  */
 225       clone_body (clone, fn, decl_map);
 226
 227       /* Clean up.  */
 228       pointer_map_destroy (decl_map);
 229
 230       /* The clone can throw iff the original function can throw.  */
 231       cp_function_chain->can_throw = !TREE_NOTHROW (fn);
 232
 233       /* Now, expand this function into RTL, if appropriate.  */
 234       finish_function (0);
 235       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
 236       DECL_SAVED_TREE (clone) = NULL;
 237       expand_or_defer_fn (clone);
 238       first = false;
 239     }
 240   pop_from_top_level ();
 241
 242   /* We don't need to process the original function any further.  */
 243   return 1;
 244 }