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0e48b5a2 | 1 | /* Language-level data type conversion for GNU C. |
9dcd6f09 | 2 | Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005, 2007 |
35b1a6fa | 3 | Free Software Foundation, Inc. |
0e48b5a2 | 4 | |
1322177d | 5 | This file is part of GCC. |
0e48b5a2 | 6 | |
1322177d LB |
7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 9 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 10 | version. |
0e48b5a2 | 11 | |
1322177d LB |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
0e48b5a2 RS |
16 | |
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
0e48b5a2 RS |
20 | |
21 | ||
22 | /* This file contains the functions for converting C expressions | |
23 | to different data types. The only entry point is `convert'. | |
24 | Every language front end must have a `convert' function | |
25 | but what kind of conversions it does will depend on the language. */ | |
26 | ||
27 | #include "config.h" | |
c5c76735 | 28 | #include "system.h" |
4977bab6 ZW |
29 | #include "coretypes.h" |
30 | #include "tm.h" | |
0e48b5a2 RS |
31 | #include "tree.h" |
32 | #include "flags.h" | |
10055ae2 | 33 | #include "convert.h" |
a40179bd | 34 | #include "c-common.h" |
85498824 | 35 | #include "c-tree.h" |
e57e265b | 36 | #include "langhooks.h" |
5f6da302 | 37 | #include "toplev.h" |
4de67c26 | 38 | #include "target.h" |
0e48b5a2 RS |
39 | |
40 | /* Change of width--truncation and extension of integers or reals-- | |
41 | is represented with NOP_EXPR. Proper functioning of many things | |
42 | assumes that no other conversions can be NOP_EXPRs. | |
43 | ||
44 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
45 | Converting integer to real uses FLOAT_EXPR | |
46 | and real to integer uses FIX_TRUNC_EXPR. | |
47 | ||
48 | Here is a list of all the functions that assume that widening and | |
49 | narrowing is always done with a NOP_EXPR: | |
10055ae2 | 50 | In convert.c, convert_to_integer. |
78ef5b89 NB |
51 | In c-typeck.c, build_binary_op (boolean ops), and |
52 | c_common_truthvalue_conversion. | |
0e48b5a2 RS |
53 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
54 | In fold-const.c: fold. | |
55 | In tree.c: get_narrower and get_unwidened. */ | |
56 | \f | |
57 | /* Subroutines of `convert'. */ | |
58 | ||
0e48b5a2 | 59 | |
0e48b5a2 RS |
60 | \f |
61 | /* Create an expression whose value is that of EXPR, | |
62 | converted to type TYPE. The TREE_TYPE of the value | |
63 | is always TYPE. This function implements all reasonable | |
64 | conversions; callers should filter out those that are | |
65 | not permitted by the language being compiled. */ | |
66 | ||
67 | tree | |
35b1a6fa | 68 | convert (tree type, tree expr) |
0e48b5a2 | 69 | { |
b3694847 SS |
70 | tree e = expr; |
71 | enum tree_code code = TREE_CODE (type); | |
4de67c26 | 72 | const char *invalid_conv_diag; |
0e48b5a2 | 73 | |
4de67c26 JM |
74 | if (type == error_mark_node |
75 | || expr == error_mark_node | |
76 | || TREE_TYPE (expr) == error_mark_node) | |
77 | return error_mark_node; | |
78 | ||
79 | if ((invalid_conv_diag | |
80 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
81 | { | |
82 | error (invalid_conv_diag); | |
83 | return error_mark_node; | |
84 | } | |
85 | ||
86 | if (type == TREE_TYPE (expr)) | |
0e48b5a2 | 87 | return expr; |
17aec3eb | 88 | |
412a4297 | 89 | if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) |
4c7a6c1b | 90 | return fold_convert (type, expr); |
0e48b5a2 RS |
91 | if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) |
92 | return error_mark_node; | |
93 | if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) | |
94 | { | |
95 | error ("void value not ignored as it ought to be"); | |
96 | return error_mark_node; | |
97 | } | |
98 | if (code == VOID_TYPE) | |
4c7a6c1b | 99 | return fold_convert (type, e); |
0e48b5a2 RS |
100 | if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) |
101 | return fold (convert_to_integer (type, e)); | |
19552aa5 | 102 | if (code == BOOLEAN_TYPE) |
4c7a6c1b | 103 | return fold_convert (type, c_objc_common_truthvalue_conversion (expr)); |
98d64f69 | 104 | if (code == POINTER_TYPE || code == REFERENCE_TYPE) |
0e48b5a2 RS |
105 | return fold (convert_to_pointer (type, e)); |
106 | if (code == REAL_TYPE) | |
107 | return fold (convert_to_real (type, e)); | |
0f996086 CF |
108 | if (code == FIXED_POINT_TYPE) |
109 | return fold (convert_to_fixed (type, e)); | |
c050422f RS |
110 | if (code == COMPLEX_TYPE) |
111 | return fold (convert_to_complex (type, e)); | |
0b4565c9 BS |
112 | if (code == VECTOR_TYPE) |
113 | return fold (convert_to_vector (type, e)); | |
6de9cd9a DN |
114 | if ((code == RECORD_TYPE || code == UNION_TYPE) |
115 | && lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) | |
116 | return e; | |
0e48b5a2 RS |
117 | |
118 | error ("conversion to non-scalar type requested"); | |
119 | return error_mark_node; | |
120 | } |