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[/] [openrisc/] [trunk/] [gnu-old/] [gcc-4.2.2/] [gcc/] [c-convert.c] - Rev 816
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/* Language-level data type conversion for GNU C. Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005, 2007 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/>. */ /* This file contains the functions for converting C expressions to different data types. The only entry point is `convert'. Every language front end must have a `convert' function but what kind of conversions it does will depend on the language. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "flags.h" #include "convert.h" #include "c-common.h" #include "c-tree.h" #include "langhooks.h" #include "toplev.h" #include "target.h" /* Change of width--truncation and extension of integers or reals-- is represented with NOP_EXPR. Proper functioning of many things assumes that no other conversions can be NOP_EXPRs. Conversion between integer and pointer is represented with CONVERT_EXPR. Converting integer to real uses FLOAT_EXPR and real to integer uses FIX_TRUNC_EXPR. Here is a list of all the functions that assume that widening and narrowing is always done with a NOP_EXPR: In convert.c, convert_to_integer. In c-typeck.c, build_binary_op (boolean ops), and c_common_truthvalue_conversion. In expr.c: expand_expr, for operands of a MULT_EXPR. In fold-const.c: fold. In tree.c: get_narrower and get_unwidened. */ /* Subroutines of `convert'. */ /* Create an expression whose value is that of EXPR, converted to type TYPE. The TREE_TYPE of the value is always TYPE. This function implements all reasonable conversions; callers should filter out those that are not permitted by the language being compiled. */ tree convert (tree type, tree expr) { tree e = expr; enum tree_code code = TREE_CODE (type); const char *invalid_conv_diag; if (type == error_mark_node || expr == error_mark_node || TREE_TYPE (expr) == error_mark_node) return error_mark_node; if ((invalid_conv_diag = targetm.invalid_conversion (TREE_TYPE (expr), type))) { error (invalid_conv_diag); return error_mark_node; } if (type == TREE_TYPE (expr)) return expr; if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) return fold_convert (type, expr); if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) return error_mark_node; if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) { error ("void value not ignored as it ought to be"); return error_mark_node; } if (code == VOID_TYPE) return fold_convert (type, e); if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) return fold (convert_to_integer (type, e)); if (code == BOOLEAN_TYPE) return fold_convert (type, c_objc_common_truthvalue_conversion (expr)); if (code == POINTER_TYPE || code == REFERENCE_TYPE) return fold (convert_to_pointer (type, e)); if (code == REAL_TYPE) return fold (convert_to_real (type, e)); if (code == COMPLEX_TYPE) return fold (convert_to_complex (type, e)); if (code == VECTOR_TYPE) return fold (convert_to_vector (type, e)); if ((code == RECORD_TYPE || code == UNION_TYPE) && lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) return e; error ("conversion to non-scalar type requested"); return error_mark_node; }