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Diffstat (limited to 'gnu/usr.bin/cc/cc1/c-convert.c')
-rw-r--r-- | gnu/usr.bin/cc/cc1/c-convert.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/gnu/usr.bin/cc/cc1/c-convert.c b/gnu/usr.bin/cc/cc1/c-convert.c new file mode 100644 index 0000000..cfa590c --- /dev/null +++ b/gnu/usr.bin/cc/cc1/c-convert.c @@ -0,0 +1,95 @@ +/* Language-level data type conversion for GNU C. + Copyright (C) 1987, 1988, 1991 Free Software Foundation, Inc. + +This file is part of GNU CC. + +GNU CC 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. + +GNU CC 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 GNU CC; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, 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 "tree.h" +#include "flags.h" +#include "convert.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 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 (type, expr) + tree type, expr; +{ + register tree e = expr; + register enum tree_code code = TREE_CODE (type); + + if (type == TREE_TYPE (expr) + || TREE_CODE (expr) == ERROR_MARK) + return expr; + if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) + return fold (build1 (NOP_EXPR, 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 build1 (CONVERT_EXPR, type, e); +#if 0 + /* This is incorrect. A truncation can't be stripped this way. + Extensions will be stripped by the use of get_unwidened. */ + if (TREE_CODE (expr) == NOP_EXPR) + return convert (type, TREE_OPERAND (expr, 0)); +#endif + if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) + return fold (convert_to_integer (type, e)); + if (code == POINTER_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)); + + error ("conversion to non-scalar type requested"); + return error_mark_node; +} |