gcc/cp/expr.c

   1 /* Convert language-specific tree expression to rtl instructions,
   2    for GNU compiler.
   3    Copyright (C) 1988-2017 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 "cp-tree.h"
  26
  27 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  28
  29 tree
  30 cplus_expand_constant (tree cst)
  31 {
  32   switch (TREE_CODE (cst))
  33     {
  34     case PTRMEM_CST:
  35       {
  36         tree type = TREE_TYPE (cst);
  37         tree member;
  38
  39         /* Find the member.  */
  40         member = PTRMEM_CST_MEMBER (cst);
  41
  42         /* We can't lower this until the class is complete.  */
  43         if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
  44           return cst;
  45
  46         if (TREE_CODE (member) == FIELD_DECL)
  47           {
  48             /* Find the offset for the field.  */
  49             cst = byte_position (member);
  50             while (!same_type_p (DECL_CONTEXT (member),
  51                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  52               {
  53                 /* The MEMBER must have been nestled within an
  54                    anonymous aggregate contained in TYPE.  Find the
  55                    anonymous aggregate.  */
  56                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  57                                             DECL_CONTEXT (member));
  58                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  59               }
  60             cst = fold (build_nop (type, cst));
  61           }
  62         else
  63           {
  64             tree delta;
  65             tree pfn;
  66
  67             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  68             cst = build_ptrmemfunc1 (type, delta, pfn);
  69           }
  70       }
  71       break;
  72
  73     case CONSTRUCTOR:
  74       {
  75         constructor_elt *elt;
  76         unsigned HOST_WIDE_INT idx;
  77         FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
  78           elt->value = cplus_expand_constant (elt->value);
  79       }
  80
  81     default:
  82       /* There's nothing to do.  */
  83       break;
  84     }
  85
  86   return cst;
  87 }
  88
  89 /* Called whenever the expression EXPR is used in an rvalue context.
  90    When REJECT_BUILTIN is true the expression is checked to make sure
  91    it doesn't make it possible to obtain the address of a GCC built-in
  92    function with no library fallback (or any of its bits, such as in
  93    a conversion to bool).  */
  94 tree
  95 mark_rvalue_use (tree expr,
  96                  location_t loc /* = UNKNOWN_LOCATION */,
  97                  bool reject_builtin /* = true */)
  98 {
  99   if (reject_builtin && reject_gcc_builtin (expr, loc))
 100     return error_mark_node;
 101
 102   mark_exp_read (expr);
 103   return expr;
 104 }
 105
 106 /* Called whenever an expression is used in an 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     case NON_DEPENDENT_EXPR:
 149     case VIEW_CONVERT_EXPR:
 150       mark_exp_read (TREE_OPERAND (exp, 0));
 151       break;
 152     case COMPOUND_EXPR:
 153       mark_exp_read (TREE_OPERAND (exp, 1));
 154       break;
 155     case COND_EXPR:
 156       if (TREE_OPERAND (exp, 1))
 157         mark_exp_read (TREE_OPERAND (exp, 1));
 158       if (TREE_OPERAND (exp, 2))
 159         mark_exp_read (TREE_OPERAND (exp, 2));
 160       break;
 161     default:
 162       break;
 163     }
 164 }
 165