gcc/cp/expr.c

/* Convert language-specific tree expression to rtl instructions,
   for GNU compiler.
   Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   2000, 2001, 2002, 2003, 2004, 2007, 2010 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */


#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "flags.h"
#include "cp-tree.h"
#include "tm_p.h"

/* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */

tree
cplus_expand_constant (tree cst)
{
  switch (TREE_CODE (cst))
    {
    case PTRMEM_CST:
      {
	tree type = TREE_TYPE (cst);
	tree member;

	/* Find the member.  */
	member = PTRMEM_CST_MEMBER (cst);

	if (TREE_CODE (member) == FIELD_DECL)
	  {
	    /* Find the offset for the field.  */
	    cst = byte_position (member);
	    while (!same_type_p (DECL_CONTEXT (member),
				 TYPE_PTRMEM_CLASS_TYPE (type)))
	      {
		/* The MEMBER must have been nestled within an
		   anonymous aggregate contained in TYPE.  Find the
		   anonymous aggregate.  */
		member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
					    DECL_CONTEXT (member));
		cst = size_binop (PLUS_EXPR, cst, byte_position (member));
	      }
	    cst = fold (build_nop (type, cst));
	  }
	else
	  {
	    tree delta;
	    tree pfn;

	    expand_ptrmemfunc_cst (cst, &delta, &pfn);
	    cst = build_ptrmemfunc1 (type, delta, pfn);
	  }
      }
      break;

    default:
      /* There's nothing to do.  */
      break;
    }

  return cst;
}

/* Called whenever an expression is used
   in a rvalue context.  */

tree
mark_rvalue_use (tree expr)
{
  mark_exp_read (expr);
  return expr;
}

/* Called whenever an expression is used
   in a lvalue context.  */

tree
mark_lvalue_use (tree expr)
{
  mark_exp_read (expr);
  return expr;
}

/* Called whenever an expression is used in a type use context.  */

tree
mark_type_use (tree expr)
{
  mark_exp_read (expr);
  return expr;
}

/* Mark EXP as read, not just set, for set but not used -Wunused
   warning purposes.  */

void
mark_exp_read (tree exp)
{
  if (exp == NULL)
    return;

  switch (TREE_CODE (exp))
    {
    case VAR_DECL:
    case PARM_DECL:
      DECL_READ_P (exp) = 1;
      break;
    case ARRAY_REF:
    case COMPONENT_REF:
    case MODIFY_EXPR:
    case REALPART_EXPR:
    case IMAGPART_EXPR:
    CASE_CONVERT:
    case ADDR_EXPR:
    case INDIRECT_REF:
      mark_exp_read (TREE_OPERAND (exp, 0));
      break;
    case COMPOUND_EXPR:
      mark_exp_read (TREE_OPERAND (exp, 1));
      break;
    case COND_EXPR:
      if (TREE_OPERAND (exp, 1))
	mark_exp_read (TREE_OPERAND (exp, 1));
      if (TREE_OPERAND (exp, 2))
	mark_exp_read (TREE_OPERAND (exp, 2));
      break;
    default:
      break;
    }
}