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 "input.h"
  27 #include "alias.h"
  28 #include "symtab.h"
  29 #include "tree.h"
  30 #include "flags.h"
  31 #include "cp-tree.h"
  32 #include "tm_p.h"
  33
  34 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  35
  36 tree
  37 cplus_expand_constant (tree cst)
  38 {
  39   switch (TREE_CODE (cst))
  40     {
  41     case PTRMEM_CST:
  42       {
  43         tree type = TREE_TYPE (cst);
  44         tree member;
  45
  46         /* Find the member.  */
  47         member = PTRMEM_CST_MEMBER (cst);
  48
  49         /* We can't lower this until the class is complete.  */
  50         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  51           return cst;
  52
  53         if (TREE_CODE (member) == FIELD_DECL)
  54           {
  55             /* Find the offset for the field.  */
  56             cst = byte_position (member);
  57             while (!same_type_p (DECL_CONTEXT (member),
  58                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  59               {
  60                 /* The MEMBER must have been nestled within an
  61                    anonymous aggregate contained in TYPE.  Find the
  62                    anonymous aggregate.  */
  63                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  64                                             DECL_CONTEXT (member));
  65                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  66               }
  67             cst = fold (build_nop (type, cst));
  68           }
  69         else
  70           {
  71             tree delta;
  72             tree pfn;
  73
  74             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  75             cst = build_ptrmemfunc1 (type, delta, pfn);
  76           }
  77       }
  78       break;
  79
  80     case CONSTRUCTOR:
  81       {
  82         constructor_elt *elt;
  83         unsigned HOST_WIDE_INT idx;
  84         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  85           elt->value = cplus_expand_constant (elt->value);
  86       }
  87
  88     default:
  89       /* There's nothing to do.  */
  90       break;
  91     }
  92
  93   return cst;
  94 }
  95
  96 /* Called whenever an expression is used
  97    in a rvalue context.  */
  98
  99 tree
 100 mark_rvalue_use (tree expr)
 101 {
 102   mark_exp_read (expr);
 103   return expr;
 104 }
 105
 106 /* Called whenever an expression is used
 107    in a lvalue context.  */
 108
 109 tree
 110 mark_lvalue_use (tree expr)
 111 {
 112   mark_exp_read (expr);
 113   return expr;
 114 }
 115
 116 /* Called whenever an expression is used in a type use context.  */
 117
 118 tree
 119 mark_type_use (tree expr)
 120 {
 121   mark_exp_read (expr);
 122   return expr;
 123 }
 124
 125 /* Mark EXP as read, not just set, for set but not used -Wunused
 126    warning purposes.  */
 127
 128 void
 129 mark_exp_read (tree exp)
 130 {
 131   if (exp == NULL)
 132     return;
 133
 134   switch (TREE_CODE (exp))
 135     {
 136     case VAR_DECL:
 137     case PARM_DECL:
 138       DECL_READ_P (exp) = 1;
 139       break;
 140     case ARRAY_REF:
 141     case COMPONENT_REF:
 142     case MODIFY_EXPR:
 143     case REALPART_EXPR:
 144     case IMAGPART_EXPR:
 145     CASE_CONVERT:
 146     case ADDR_EXPR:
 147     case INDIRECT_REF:
 148     case FLOAT_EXPR:
 149       mark_exp_read (TREE_OPERAND (exp, 0));
 150       break;
 151     case COMPOUND_EXPR:
 152       mark_exp_read (TREE_OPERAND (exp, 1));
 153       break;
 154     case COND_EXPR:
 155       if (TREE_OPERAND (exp, 1))
 156         mark_exp_read (TREE_OPERAND (exp, 1));
 157       if (TREE_OPERAND (exp, 2))
 158         mark_exp_read (TREE_OPERAND (exp, 2));
 159       break;
 160     default:
 161       break;
 162     }
 163 }
 164