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0e48b5a2 | 1 | /* Language-level data type conversion for GNU C. |
e146f815 | 2 | Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004 |
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 | |
9 | Software Foundation; either version 2, or (at your option) any later | |
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 | |
1322177d LB |
18 | along with GCC; see the file COPYING. If not, write to the Free |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
0e48b5a2 RS |
21 | |
22 | ||
23 | /* This file contains the functions for converting C expressions | |
24 | to different data types. The only entry point is `convert'. | |
25 | Every language front end must have a `convert' function | |
26 | but what kind of conversions it does will depend on the language. */ | |
27 | ||
28 | #include "config.h" | |
c5c76735 | 29 | #include "system.h" |
4977bab6 ZW |
30 | #include "coretypes.h" |
31 | #include "tm.h" | |
0e48b5a2 RS |
32 | #include "tree.h" |
33 | #include "flags.h" | |
10055ae2 | 34 | #include "convert.h" |
a40179bd | 35 | #include "c-common.h" |
e57e265b | 36 | #include "langhooks.h" |
5f6da302 | 37 | #include "toplev.h" |
0e48b5a2 RS |
38 | |
39 | /* Change of width--truncation and extension of integers or reals-- | |
40 | is represented with NOP_EXPR. Proper functioning of many things | |
41 | assumes that no other conversions can be NOP_EXPRs. | |
42 | ||
43 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
44 | Converting integer to real uses FLOAT_EXPR | |
45 | and real to integer uses FIX_TRUNC_EXPR. | |
46 | ||
47 | Here is a list of all the functions that assume that widening and | |
48 | narrowing is always done with a NOP_EXPR: | |
10055ae2 | 49 | In convert.c, convert_to_integer. |
78ef5b89 NB |
50 | In c-typeck.c, build_binary_op (boolean ops), and |
51 | c_common_truthvalue_conversion. | |
0e48b5a2 RS |
52 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
53 | In fold-const.c: fold. | |
54 | In tree.c: get_narrower and get_unwidened. */ | |
55 | \f | |
56 | /* Subroutines of `convert'. */ | |
57 | ||
0e48b5a2 | 58 | |
0e48b5a2 RS |
59 | \f |
60 | /* Create an expression whose value is that of EXPR, | |
61 | converted to type TYPE. The TREE_TYPE of the value | |
62 | is always TYPE. This function implements all reasonable | |
63 | conversions; callers should filter out those that are | |
64 | not permitted by the language being compiled. */ | |
65 | ||
66 | tree | |
35b1a6fa | 67 | convert (tree type, tree expr) |
0e48b5a2 | 68 | { |
b3694847 SS |
69 | tree e = expr; |
70 | enum tree_code code = TREE_CODE (type); | |
0e48b5a2 | 71 | |
412a4297 | 72 | if (type == TREE_TYPE (expr) |
17aec3eb RK |
73 | || TREE_CODE (expr) == ERROR_MARK |
74 | || code == ERROR_MARK || TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) | |
0e48b5a2 | 75 | return expr; |
17aec3eb | 76 | |
412a4297 | 77 | if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) |
542bc952 | 78 | return fold (build1 (NOP_EXPR, type, expr)); |
0e48b5a2 RS |
79 | if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) |
80 | return error_mark_node; | |
81 | if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) | |
82 | { | |
83 | error ("void value not ignored as it ought to be"); | |
84 | return error_mark_node; | |
85 | } | |
86 | if (code == VOID_TYPE) | |
87 | return build1 (CONVERT_EXPR, type, e); | |
88 | #if 0 | |
89 | /* This is incorrect. A truncation can't be stripped this way. | |
90 | Extensions will be stripped by the use of get_unwidened. */ | |
91 | if (TREE_CODE (expr) == NOP_EXPR) | |
92 | return convert (type, TREE_OPERAND (expr, 0)); | |
93 | #endif | |
94 | if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) | |
95 | return fold (convert_to_integer (type, e)); | |
19552aa5 | 96 | if (code == BOOLEAN_TYPE) |
c3cd9c8b | 97 | { |
ae2bcd98 | 98 | tree t = lang_hooks.truthvalue_conversion (expr); |
e57e265b PB |
99 | if (TREE_CODE (t) == ERROR_MARK) |
100 | return t; | |
101 | ||
78ef5b89 NB |
102 | /* If it returns a NOP_EXPR, we must fold it here to avoid |
103 | infinite recursion between fold () and convert (). */ | |
c3cd9c8b JM |
104 | if (TREE_CODE (t) == NOP_EXPR) |
105 | return fold (build1 (NOP_EXPR, type, TREE_OPERAND (t, 0))); | |
106 | else | |
107 | return fold (build1 (NOP_EXPR, type, t)); | |
108 | } | |
98d64f69 | 109 | if (code == POINTER_TYPE || code == REFERENCE_TYPE) |
0e48b5a2 RS |
110 | return fold (convert_to_pointer (type, e)); |
111 | if (code == REAL_TYPE) | |
112 | return fold (convert_to_real (type, e)); | |
c050422f RS |
113 | if (code == COMPLEX_TYPE) |
114 | return fold (convert_to_complex (type, e)); | |
0b4565c9 BS |
115 | if (code == VECTOR_TYPE) |
116 | return fold (convert_to_vector (type, e)); | |
6de9cd9a DN |
117 | if ((code == RECORD_TYPE || code == UNION_TYPE) |
118 | && lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) | |
119 | return e; | |
0e48b5a2 RS |
120 | |
121 | error ("conversion to non-scalar type requested"); | |
122 | return error_mark_node; | |
123 | } |