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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [c-convert.c] - Blame information for rev 729

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1 684 jeremybenn
/* Language-level data type conversion for GNU C.
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   Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005, 2007, 2008,
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   2009, 2010 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3.  If not see
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<http://www.gnu.org/licenses/>.  */
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/* This file contains the functions for converting C expressions
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   to different data types.  The only entry point is `convert'.
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   Every language front end must have a `convert' function
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   but what kind of conversions it does will depend on the language.  */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "flags.h"
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#include "convert.h"
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#include "c-family/c-common.h"
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#include "c-tree.h"
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#include "langhooks.h"
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#include "target.h"
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/* Change of width--truncation and extension of integers or reals--
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   is represented with NOP_EXPR.  Proper functioning of many things
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   assumes that no other conversions can be NOP_EXPRs.
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   Conversion between integer and pointer is represented with CONVERT_EXPR.
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   Converting integer to real uses FLOAT_EXPR
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   and real to integer uses FIX_TRUNC_EXPR.
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   Here is a list of all the functions that assume that widening and
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   narrowing is always done with a NOP_EXPR:
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     In convert.c, convert_to_integer.
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     In c-typeck.c, build_binary_op (boolean ops), and
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        c_common_truthvalue_conversion.
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     In expr.c: expand_expr, for operands of a MULT_EXPR.
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     In fold-const.c: fold.
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     In tree.c: get_narrower and get_unwidened.  */
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/* Subroutines of `convert'.  */
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/* Create an expression whose value is that of EXPR,
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   converted to type TYPE.  The TREE_TYPE of the value
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   is always TYPE.  This function implements all reasonable
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   conversions; callers should filter out those that are
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   not permitted by the language being compiled.  */
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tree
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convert (tree type, tree expr)
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{
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  tree e = expr;
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  enum tree_code code = TREE_CODE (type);
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  const char *invalid_conv_diag;
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  tree ret;
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  location_t loc = EXPR_LOCATION (expr);
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  if (type == error_mark_node
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      || expr == error_mark_node
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      || TREE_TYPE (expr) == error_mark_node)
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    return error_mark_node;
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  if ((invalid_conv_diag
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       = targetm.invalid_conversion (TREE_TYPE (expr), type)))
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    {
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      error (invalid_conv_diag);
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      return error_mark_node;
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    }
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  if (type == TREE_TYPE (expr))
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    return expr;
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  ret = targetm.convert_to_type (type, expr);
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  if (ret)
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      return ret;
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  STRIP_TYPE_NOPS (e);
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  if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
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    return fold_convert_loc (loc, type, expr);
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  if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK)
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    return error_mark_node;
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  if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE)
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    {
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      error ("void value not ignored as it ought to be");
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      return error_mark_node;
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    }
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  switch (code)
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    {
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    case VOID_TYPE:
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      return fold_convert_loc (loc, type, e);
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    case INTEGER_TYPE:
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    case ENUMERAL_TYPE:
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      ret = convert_to_integer (type, e);
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      goto maybe_fold;
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    case BOOLEAN_TYPE:
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      return fold_convert_loc
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        (loc, type, c_objc_common_truthvalue_conversion (input_location, expr));
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    case POINTER_TYPE:
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    case REFERENCE_TYPE:
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      ret = convert_to_pointer (type, e);
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      goto maybe_fold;
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    case REAL_TYPE:
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      ret = convert_to_real (type, e);
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      goto maybe_fold;
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    case FIXED_POINT_TYPE:
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      ret = convert_to_fixed (type, e);
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      goto maybe_fold;
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    case COMPLEX_TYPE:
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      /* If converting from COMPLEX_TYPE to a different COMPLEX_TYPE
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         and e is not COMPLEX_EXPR, convert_to_complex uses save_expr,
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         but for the C FE c_save_expr needs to be called instead.  */
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      if (TREE_CODE (TREE_TYPE (e)) == COMPLEX_TYPE)
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        {
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          tree subtype = TREE_TYPE (type);
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          tree elt_type = TREE_TYPE (TREE_TYPE (e));
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          if (TYPE_MAIN_VARIANT (elt_type) != TYPE_MAIN_VARIANT (subtype)
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              && TREE_CODE (e) != COMPLEX_EXPR)
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            {
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              if (in_late_binary_op)
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                e = save_expr (e);
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              else
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                e = c_save_expr (e);
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              ret
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                = fold_build2 (COMPLEX_EXPR, type,
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                               convert (subtype,
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                                        fold_build1 (REALPART_EXPR,
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                                                     elt_type, e)),
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                               convert (subtype,
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                                        fold_build1 (IMAGPART_EXPR,
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                                                     elt_type, e)));
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              goto maybe_fold;
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            }
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        }
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      ret = convert_to_complex (type, e);
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      goto maybe_fold;
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    case VECTOR_TYPE:
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      ret = convert_to_vector (type, e);
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      goto maybe_fold;
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    case RECORD_TYPE:
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    case UNION_TYPE:
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      if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr)))
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        return e;
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      break;
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    default:
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      break;
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    maybe_fold:
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      if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR)
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        ret = fold (ret);
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      return ret;
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    }
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  error ("conversion to non-scalar type requested");
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  return error_mark_node;
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}

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