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 "hash-set.h"
  27 #include "machmode.h"
  28 #include "vec.h"
  29 #include "double-int.h"
  30 #include "input.h"
  31 #include "alias.h"
  32 #include "symtab.h"
  33 #include "wide-int.h"
  34 #include "inchash.h"
  35 #include "tree.h"
  36 #include "flags.h"
  37 #include "cp-tree.h"
  38 #include "tm_p.h"
  39
  40 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  41
  42 tree
  43 cplus_expand_constant (tree cst)
  44 {
  45   switch (TREE_CODE (cst))
  46     {
  47     case PTRMEM_CST:
  48       {
  49         tree type = TREE_TYPE (cst);
  50         tree member;
  51
  52         /* Find the member.  */
  53         member = PTRMEM_CST_MEMBER (cst);
  54
  55         /* We can't lower this until the class is complete.  */
  56         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  57           return cst;
  58
  59         if (TREE_CODE (member) == FIELD_DECL)
  60           {
  61             /* Find the offset for the field.  */
  62             cst = byte_position (member);
  63             while (!same_type_p (DECL_CONTEXT (member),
  64                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  65               {
  66                 /* The MEMBER must have been nestled within an
  67                    anonymous aggregate contained in TYPE.  Find the
  68                    anonymous aggregate.  */
  69                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  70                                             DECL_CONTEXT (member));
  71                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  72               }
  73             cst = fold (build_nop (type, cst));
  74           }
  75         else
  76           {
  77             tree delta;
  78             tree pfn;
  79
  80             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  81             cst = build_ptrmemfunc1 (type, delta, pfn);
  82           }
  83       }
  84       break;
  85
  86     case CONSTRUCTOR:
  87       {
  88         constructor_elt *elt;
  89         unsigned HOST_WIDE_INT idx;
  90         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  91           elt->value = cplus_expand_constant (elt->value);
  92       }
  93
  94     default:
  95       /* There's nothing to do.  */
  96       break;
  97     }
  98
  99   return cst;
 100 }
 101
 102 /* Called whenever an expression is used
 103    in a rvalue context.  */
 104
 105 tree
 106 mark_rvalue_use (tree expr)
 107 {
 108   mark_exp_read (expr);
 109   return expr;
 110 }
 111
 112 /* Called whenever an expression is used
 113    in a lvalue context.  */
 114
 115 tree
 116 mark_lvalue_use (tree expr)
 117 {
 118   mark_exp_read (expr);
 119   return expr;
 120 }
 121
 122 /* Called whenever an expression is used in a type use context.  */
 123
 124 tree
 125 mark_type_use (tree expr)
 126 {
 127   mark_exp_read (expr);
 128   return expr;
 129 }
 130
 131 /* Mark EXP as read, not just set, for set but not used -Wunused
 132    warning purposes.  */
 133
 134 void
 135 mark_exp_read (tree exp)
 136 {
 137   if (exp == NULL)
 138     return;
 139
 140   switch (TREE_CODE (exp))
 141     {
 142     case VAR_DECL:
 143     case PARM_DECL:
 144       DECL_READ_P (exp) = 1;
 145       break;
 146     case ARRAY_REF:
 147     case COMPONENT_REF:
 148     case MODIFY_EXPR:
 149     case REALPART_EXPR:
 150     case IMAGPART_EXPR:
 151     CASE_CONVERT:
 152     case ADDR_EXPR:
 153     case INDIRECT_REF:
 154     case FLOAT_EXPR:
 155       mark_exp_read (TREE_OPERAND (exp, 0));
 156       break;
 157     case COMPOUND_EXPR:
 158       mark_exp_read (TREE_OPERAND (exp, 1));
 159       break;
 160     case COND_EXPR:
 161       if (TREE_OPERAND (exp, 1))
 162         mark_exp_read (TREE_OPERAND (exp, 1));
 163       if (TREE_OPERAND (exp, 2))
 164         mark_exp_read (TREE_OPERAND (exp, 2));
 165       break;
 166     default:
 167       break;
 168     }
 169 }
 170