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Diffstat (limited to 'gcc/c-convert.c')
-rw-r--r-- | gcc/c-convert.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/gcc/c-convert.c b/gcc/c-convert.c new file mode 100644 index 0000000..bf306c8 --- /dev/null +++ b/gcc/c-convert.c @@ -0,0 +1,119 @@ +/* Language-level data type conversion for GNU C. + Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005 + 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 2, 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 COPYING. If not, write to the Free +Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301, USA. */ + + +/* 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; +} |