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 "tree.h"
  28 #include "flags.h"
  29 #include "cp-tree.h"
  30 #include "tm_p.h"
  31
  32 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  33
  34 tree
  35 cplus_expand_constant (tree cst)
  36 {
  37   switch (TREE_CODE (cst))
  38     {
  39     case PTRMEM_CST:
  40       {
  41         tree type = TREE_TYPE (cst);
  42         tree member;
  43
  44         /* Find the member.  */
  45         member = PTRMEM_CST_MEMBER (cst);
  46
  47         /* We can't lower this until the class is complete.  */
  48         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  49           return cst;
  50
  51         if (TREE_CODE (member) == FIELD_DECL)
  52           {
  53             /* Find the offset for the field.  */
  54             cst = byte_position (member);
  55             while (!same_type_p (DECL_CONTEXT (member),
  56                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  57               {
  58                 /* The MEMBER must have been nestled within an
  59                    anonymous aggregate contained in TYPE.  Find the
  60                    anonymous aggregate.  */
  61                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  62                                             DECL_CONTEXT (member));
  63                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  64               }
  65             cst = fold (build_nop (type, cst));
  66           }
  67         else
  68           {
  69             tree delta;
  70             tree pfn;
  71
  72             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  73             cst = build_ptrmemfunc1 (type, delta, pfn);
  74           }
  75       }
  76       break;
  77
  78     case CONSTRUCTOR:
  79       {
  80         constructor_elt *elt;
  81         unsigned HOST_WIDE_INT idx;
  82         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  83           elt->value = cplus_expand_constant (elt->value);
  84       }
  85
  86     default:
  87       /* There's nothing to do.  */
  88       break;
  89     }
  90
  91   return cst;
  92 }
  93
  94 /* Called whenever an expression is used
  95    in a rvalue context.  */
  96
  97 tree
  98 mark_rvalue_use (tree expr)
  99 {
 100   mark_exp_read (expr);
 101   return expr;
 102 }
 103
 104 /* Called whenever an expression is used
 105    in a lvalue context.  */
 106
 107 tree
 108 mark_lvalue_use (tree expr)
 109 {
 110   mark_exp_read (expr);
 111   return expr;
 112 }
 113
 114 /* Called whenever an expression is used in a type use context.  */
 115
 116 tree
 117 mark_type_use (tree expr)
 118 {
 119   mark_exp_read (expr);
 120   return expr;
 121 }
 122
 123 /* Mark EXP as read, not just set, for set but not used -Wunused
 124    warning purposes.  */
 125
 126 void
 127 mark_exp_read (tree exp)
 128 {
 129   if (exp == NULL)
 130     return;
 131
 132   switch (TREE_CODE (exp))
 133     {
 134     case VAR_DECL:
 135     case PARM_DECL:
 136       DECL_READ_P (exp) = 1;
 137       break;
 138     case ARRAY_REF:
 139     case COMPONENT_REF:
 140     case MODIFY_EXPR:
 141     case REALPART_EXPR:
 142     case IMAGPART_EXPR:
 143     CASE_CONVERT:
 144     case ADDR_EXPR:
 145     case INDIRECT_REF:
 146     case FLOAT_EXPR:
 147       mark_exp_read (TREE_OPERAND (exp, 0));
 148       break;
 149     case COMPOUND_EXPR:
 150       mark_exp_read (TREE_OPERAND (exp, 1));
 151       break;
 152     case COND_EXPR:
 153       if (TREE_OPERAND (exp, 1))
 154         mark_exp_read (TREE_OPERAND (exp, 1));
 155       if (TREE_OPERAND (exp, 2))
 156         mark_exp_read (TREE_OPERAND (exp, 2));
 157       break;
 158     default:
 159       break;
 160     }
 161 }
 162