gcc/cp/expr.c

   1 /* Convert language-specific tree expression to rtl instructions,
   2    for GNU compiler.
   3    Copyright (C) 1988-2015 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "alias.h"
  27 #include "symtab.h"
  28 #include "tree.h"
  29 #include "flags.h"
  30 #include "cp-tree.h"
  31 #include "tm_p.h"
  32
  33 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  34
  35 tree
  36 cplus_expand_constant (tree cst)
  37 {
  38   switch (TREE_CODE (cst))
  39     {
  40     case PTRMEM_CST:
  41       {
  42         tree type = TREE_TYPE (cst);
  43         tree member;
  44
  45         /* Find the member.  */
  46         member = PTRMEM_CST_MEMBER (cst);
  47
  48         /* We can't lower this until the class is complete.  */
  49         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  50           return cst;
  51
  52         if (TREE_CODE (member) == FIELD_DECL)
  53           {
  54             /* Find the offset for the field.  */
  55             cst = byte_position (member);
  56             while (!same_type_p (DECL_CONTEXT (member),
  57                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  58               {
  59                 /* The MEMBER must have been nestled within an
  60                    anonymous aggregate contained in TYPE.  Find the
  61                    anonymous aggregate.  */
  62                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  63                                             DECL_CONTEXT (member));
  64                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  65               }
  66             cst = fold (build_nop (type, cst));
  67           }
  68         else
  69           {
  70             tree delta;
  71             tree pfn;
  72
  73             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  74             cst = build_ptrmemfunc1 (type, delta, pfn);
  75           }
  76       }
  77       break;
  78
  79     case CONSTRUCTOR:
  80       {
  81         constructor_elt *elt;
  82         unsigned HOST_WIDE_INT idx;
  83         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  84           elt->value = cplus_expand_constant (elt->value);
  85       }
  86
  87     default:
  88       /* There's nothing to do.  */
  89       break;
  90     }
  91
  92   return cst;
  93 }
  94
  95 /* Called whenever an expression is used
  96    in a rvalue context.  */
  97
  98 tree
  99 mark_rvalue_use (tree expr)
 100 {
 101   mark_exp_read (expr);
 102   return expr;
 103 }
 104
 105 /* Called whenever an expression is used
 106    in a lvalue context.  */
 107
 108 tree
 109 mark_lvalue_use (tree expr)
 110 {
 111   mark_exp_read (expr);
 112   return expr;
 113 }
 114
 115 /* Called whenever an expression is used in a type use context.  */
 116
 117 tree
 118 mark_type_use (tree expr)
 119 {
 120   mark_exp_read (expr);
 121   return expr;
 122 }
 123
 124 /* Mark EXP as read, not just set, for set but not used -Wunused
 125    warning purposes.  */
 126
 127 void
 128 mark_exp_read (tree exp)
 129 {
 130   if (exp == NULL)
 131     return;
 132
 133   switch (TREE_CODE (exp))
 134     {
 135     case VAR_DECL:
 136     case PARM_DECL:
 137       DECL_READ_P (exp) = 1;
 138       break;
 139     case ARRAY_REF:
 140     case COMPONENT_REF:
 141     case MODIFY_EXPR:
 142     case REALPART_EXPR:
 143     case IMAGPART_EXPR:
 144     CASE_CONVERT:
 145     case ADDR_EXPR:
 146     case INDIRECT_REF:
 147     case FLOAT_EXPR:
 148       mark_exp_read (TREE_OPERAND (exp, 0));
 149       break;
 150     case COMPOUND_EXPR:
 151       mark_exp_read (TREE_OPERAND (exp, 1));
 152       break;
 153     case COND_EXPR:
 154       if (TREE_OPERAND (exp, 1))
 155         mark_exp_read (TREE_OPERAND (exp, 1));
 156       if (TREE_OPERAND (exp, 2))
 157         mark_exp_read (TREE_OPERAND (exp, 2));
 158       break;
 159     default:
 160       break;
 161     }
 162 }
 163