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568356fe | 1 | /* Language-level data type conversion for GNU C. |
a75b1c71 | 2 | Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005, 2007, 2008, |
92468061 | 3 | 2009, 2010 Free Software Foundation, Inc. |
568356fe | 4 | |
f12b58b3 | 5 | This file is part of GCC. |
568356fe | 6 | |
f12b58b3 | 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 | |
8c4c00c1 | 9 | Software Foundation; either version 3, or (at your option) any later |
f12b58b3 | 10 | version. |
568356fe | 11 | |
f12b58b3 | 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. | |
568356fe | 16 | |
17 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
568356fe | 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" | |
7014838c | 28 | #include "system.h" |
805e22b2 | 29 | #include "coretypes.h" |
30 | #include "tm.h" | |
568356fe | 31 | #include "tree.h" |
32 | #include "flags.h" | |
de6985af | 33 | #include "convert.h" |
7bedc3a0 | 34 | #include "c-family/c-common.h" |
45a78cc0 | 35 | #include "c-tree.h" |
d1b92730 | 36 | #include "langhooks.h" |
7a979707 | 37 | #include "target.h" |
568356fe | 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: | |
de6985af | 49 | In convert.c, convert_to_integer. |
aff9e656 | 50 | In c-typeck.c, build_binary_op (boolean ops), and |
51 | c_common_truthvalue_conversion. | |
568356fe | 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 | ||
568356fe | 58 | |
568356fe | 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 | |
1cae46be | 67 | convert (tree type, tree expr) |
568356fe | 68 | { |
19cb6b50 | 69 | tree e = expr; |
70 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 71 | const char *invalid_conv_diag; |
9a8bed72 | 72 | tree ret; |
389dd41b | 73 | location_t loc = EXPR_LOCATION (expr); |
568356fe | 74 | |
7a979707 | 75 | if (type == error_mark_node |
76 | || expr == error_mark_node | |
77 | || TREE_TYPE (expr) == error_mark_node) | |
78 | return error_mark_node; | |
79 | ||
80 | if ((invalid_conv_diag | |
81 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
82 | { | |
83 | error (invalid_conv_diag); | |
84 | return error_mark_node; | |
85 | } | |
86 | ||
87 | if (type == TREE_TYPE (expr)) | |
568356fe | 88 | return expr; |
2b3c93a3 | 89 | ret = targetm.convert_to_type (type, expr); |
90 | if (ret) | |
91 | return ret; | |
b8e0d419 | 92 | |
a75b1c71 | 93 | STRIP_TYPE_NOPS (e); |
94 | ||
896ef382 | 95 | if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) |
389dd41b | 96 | return fold_convert_loc (loc, type, expr); |
568356fe | 97 | if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) |
98 | return error_mark_node; | |
99 | if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) | |
100 | { | |
101 | error ("void value not ignored as it ought to be"); | |
102 | return error_mark_node; | |
103 | } | |
9a8bed72 | 104 | |
105 | switch (code) | |
106 | { | |
107 | case VOID_TYPE: | |
389dd41b | 108 | return fold_convert_loc (loc, type, e); |
9a8bed72 | 109 | |
110 | case INTEGER_TYPE: | |
111 | case ENUMERAL_TYPE: | |
112 | ret = convert_to_integer (type, e); | |
113 | goto maybe_fold; | |
114 | ||
115 | case BOOLEAN_TYPE: | |
389dd41b | 116 | return fold_convert_loc |
117 | (loc, type, c_objc_common_truthvalue_conversion (input_location, expr)); | |
9a8bed72 | 118 | |
119 | case POINTER_TYPE: | |
120 | case REFERENCE_TYPE: | |
121 | ret = convert_to_pointer (type, e); | |
122 | goto maybe_fold; | |
123 | ||
124 | case REAL_TYPE: | |
125 | ret = convert_to_real (type, e); | |
126 | goto maybe_fold; | |
127 | ||
128 | case FIXED_POINT_TYPE: | |
129 | ret = convert_to_fixed (type, e); | |
130 | goto maybe_fold; | |
131 | ||
132 | case COMPLEX_TYPE: | |
133 | ret = convert_to_complex (type, e); | |
134 | goto maybe_fold; | |
135 | ||
136 | case VECTOR_TYPE: | |
137 | ret = convert_to_vector (type, e); | |
138 | goto maybe_fold; | |
139 | ||
140 | case RECORD_TYPE: | |
141 | case UNION_TYPE: | |
142 | if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) | |
143 | return e; | |
144 | break; | |
145 | ||
146 | default: | |
147 | break; | |
148 | ||
149 | maybe_fold: | |
150 | if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR) | |
151 | ret = fold (ret); | |
152 | return ret; | |
153 | } | |
568356fe | 154 | |
155 | error ("conversion to non-scalar type requested"); | |
156 | return error_mark_node; | |
157 | } |