gcc/cp/expr.c

   1 /* Convert language-specific tree expression to rtl instructions,
   2    for GNU compiler.
   3    Copyright (C) 1988-2014 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 "tree.h"
  27 #include "flags.h"
  28 #include "cp-tree.h"
  29 #include "tm_p.h"
  30
  31 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  32
  33 tree
  34 cplus_expand_constant (tree cst)
  35 {
  36   switch (TREE_CODE (cst))
  37     {
  38     case PTRMEM_CST:
  39       {
  40         tree type = TREE_TYPE (cst);
  41         tree member;
  42
  43         /* Find the member.  */
  44         member = PTRMEM_CST_MEMBER (cst);
  45
  46         /* We can't lower this until the class is complete.  */
  47         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  48           return cst;
  49
  50         if (TREE_CODE (member) == FIELD_DECL)
  51           {
  52             /* Find the offset for the field.  */
  53             cst = byte_position (member);
  54             while (!same_type_p (DECL_CONTEXT (member),
  55                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  56               {
  57                 /* The MEMBER must have been nestled within an
  58                    anonymous aggregate contained in TYPE.  Find the
  59                    anonymous aggregate.  */
  60                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  61                                             DECL_CONTEXT (member));
  62                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  63               }
  64             cst = fold (build_nop (type, cst));
  65           }
  66         else
  67           {
  68             tree delta;
  69             tree pfn;
  70
  71             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  72             cst = build_ptrmemfunc1 (type, delta, pfn);
  73           }
  74       }
  75       break;
  76
  77     case CONSTRUCTOR:
  78       {
  79         constructor_elt *elt;
  80         unsigned HOST_WIDE_INT idx;
  81         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  82           elt->value = cplus_expand_constant (elt->value);
  83       }
  84
  85     default:
  86       /* There's nothing to do.  */
  87       break;
  88     }
  89
  90   return cst;
  91 }
  92
  93 /* Called whenever an expression is used
  94    in a rvalue context.  */
  95
  96 tree
  97 mark_rvalue_use (tree expr)
  98 {
  99   mark_exp_read (expr);
 100   return expr;
 101 }
 102
 103 /* Called whenever an expression is used
 104    in a lvalue context.  */
 105
 106 tree
 107 mark_lvalue_use (tree expr)
 108 {
 109   mark_exp_read (expr);
 110   return expr;
 111 }
 112
 113 /* Called whenever an expression is used in a type use context.  */
 114
 115 tree
 116 mark_type_use (tree expr)
 117 {
 118   mark_exp_read (expr);
 119   return expr;
 120 }
 121
 122 /* Mark EXP as read, not just set, for set but not used -Wunused
 123    warning purposes.  */
 124
 125 void
 126 mark_exp_read (tree exp)
 127 {
 128   if (exp == NULL)
 129     return;
 130
 131   switch (TREE_CODE (exp))
 132     {
 133     case VAR_DECL:
 134     case PARM_DECL:
 135       DECL_READ_P (exp) = 1;
 136       break;
 137     case ARRAY_REF:
 138     case COMPONENT_REF:
 139     case MODIFY_EXPR:
 140     case REALPART_EXPR:
 141     case IMAGPART_EXPR:
 142     CASE_CONVERT:
 143     case ADDR_EXPR:
 144     case INDIRECT_REF:
 145     case FLOAT_EXPR:
 146       mark_exp_read (TREE_OPERAND (exp, 0));
 147       break;
 148     case COMPOUND_EXPR:
 149       mark_exp_read (TREE_OPERAND (exp, 1));
 150       break;
 151     case COND_EXPR:
 152       if (TREE_OPERAND (exp, 1))
 153         mark_exp_read (TREE_OPERAND (exp, 1));
 154       if (TREE_OPERAND (exp, 2))
 155         mark_exp_read (TREE_OPERAND (exp, 2));
 156       break;
 157     default:
 158       break;
 159     }
 160 }
 161