Mercurial > hg > CbC > CbC_gcc
comparison gcc/c/c-convert.c @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 84e7813d76e9 |
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68:561a7518be6b | 111:04ced10e8804 |
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1 /* Language-level data type conversion for GNU C. | |
2 Copyright (C) 1987-2017 Free Software Foundation, Inc. | |
3 | |
4 This file is part of GCC. | |
5 | |
6 GCC is free software; you can redistribute it and/or modify it under | |
7 the terms of the GNU General Public License as published by the Free | |
8 Software Foundation; either version 3, or (at your option) any later | |
9 version. | |
10 | |
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 for more details. | |
15 | |
16 You should have received a copy of the GNU General Public License | |
17 along with GCC; see the file COPYING3. If not see | |
18 <http://www.gnu.org/licenses/>. */ | |
19 | |
20 | |
21 /* This file contains the functions for converting C expressions | |
22 to different data types. The only entry point is `convert'. | |
23 Every language front end must have a `convert' function | |
24 but what kind of conversions it does will depend on the language. */ | |
25 | |
26 #include "config.h" | |
27 #include "system.h" | |
28 #include "coretypes.h" | |
29 #include "target.h" | |
30 #include "c-tree.h" | |
31 #include "convert.h" | |
32 #include "langhooks.h" | |
33 #include "ubsan.h" | |
34 #include "stringpool.h" | |
35 #include "attribs.h" | |
36 #include "asan.h" | |
37 | |
38 /* Change of width--truncation and extension of integers or reals-- | |
39 is represented with NOP_EXPR. Proper functioning of many things | |
40 assumes that no other conversions can be NOP_EXPRs. | |
41 | |
42 Conversion between integer and pointer is represented with CONVERT_EXPR. | |
43 Converting integer to real uses FLOAT_EXPR | |
44 and real to integer uses FIX_TRUNC_EXPR. | |
45 | |
46 Here is a list of all the functions that assume that widening and | |
47 narrowing is always done with a NOP_EXPR: | |
48 In convert.c, convert_to_integer. | |
49 In c-typeck.c, build_binary_op (boolean ops), and | |
50 c_common_truthvalue_conversion. | |
51 In expr.c: expand_expr, for operands of a MULT_EXPR. | |
52 In fold-const.c: fold. | |
53 In tree.c: get_narrower and get_unwidened. */ | |
54 | |
55 /* Subroutines of `convert'. */ | |
56 | |
57 | |
58 | |
59 /* Create an expression whose value is that of EXPR, | |
60 converted to type TYPE. The TREE_TYPE of the value | |
61 is always TYPE. This function implements all reasonable | |
62 conversions; callers should filter out those that are | |
63 not permitted by the language being compiled. */ | |
64 | |
65 tree | |
66 convert (tree type, tree expr) | |
67 { | |
68 tree e = expr; | |
69 enum tree_code code = TREE_CODE (type); | |
70 const char *invalid_conv_diag; | |
71 tree ret; | |
72 location_t loc = EXPR_LOCATION (expr); | |
73 | |
74 if (type == error_mark_node | |
75 || error_operand_p (expr)) | |
76 return error_mark_node; | |
77 | |
78 if ((invalid_conv_diag | |
79 = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
80 { | |
81 error (invalid_conv_diag); | |
82 return error_mark_node; | |
83 } | |
84 | |
85 if (type == TREE_TYPE (expr)) | |
86 return expr; | |
87 ret = targetm.convert_to_type (type, expr); | |
88 if (ret) | |
89 return ret; | |
90 | |
91 STRIP_TYPE_NOPS (e); | |
92 | |
93 if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)) | |
94 && (TREE_CODE (TREE_TYPE (expr)) != COMPLEX_TYPE | |
95 || TREE_CODE (e) == COMPLEX_EXPR)) | |
96 return fold_convert_loc (loc, type, expr); | |
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 } | |
104 | |
105 switch (code) | |
106 { | |
107 case VOID_TYPE: | |
108 return fold_convert_loc (loc, type, e); | |
109 | |
110 case INTEGER_TYPE: | |
111 case ENUMERAL_TYPE: | |
112 if (sanitize_flags_p (SANITIZE_FLOAT_CAST) | |
113 && current_function_decl != NULL_TREE | |
114 && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE | |
115 && COMPLETE_TYPE_P (type)) | |
116 { | |
117 expr = save_expr (expr); | |
118 tree check = ubsan_instrument_float_cast (loc, type, expr); | |
119 expr = fold_build1 (FIX_TRUNC_EXPR, type, expr); | |
120 if (check == NULL_TREE) | |
121 return expr; | |
122 return fold_build2 (COMPOUND_EXPR, TREE_TYPE (expr), check, expr); | |
123 } | |
124 ret = convert_to_integer (type, e); | |
125 goto maybe_fold; | |
126 | |
127 case BOOLEAN_TYPE: | |
128 return fold_convert_loc | |
129 (loc, type, c_objc_common_truthvalue_conversion (input_location, expr)); | |
130 | |
131 case POINTER_TYPE: | |
132 case REFERENCE_TYPE: | |
133 ret = convert_to_pointer (type, e); | |
134 goto maybe_fold; | |
135 | |
136 case REAL_TYPE: | |
137 ret = convert_to_real (type, e); | |
138 goto maybe_fold; | |
139 | |
140 case FIXED_POINT_TYPE: | |
141 ret = convert_to_fixed (type, e); | |
142 goto maybe_fold; | |
143 | |
144 case COMPLEX_TYPE: | |
145 ret = convert_to_complex (type, e); | |
146 goto maybe_fold; | |
147 | |
148 case VECTOR_TYPE: | |
149 ret = convert_to_vector (type, e); | |
150 goto maybe_fold; | |
151 | |
152 case RECORD_TYPE: | |
153 case UNION_TYPE: | |
154 if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) | |
155 return e; | |
156 break; | |
157 | |
158 default: | |
159 break; | |
160 | |
161 maybe_fold: | |
162 if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR) | |
163 ret = fold (ret); | |
164 return ret; | |
165 } | |
166 | |
167 error ("conversion to non-scalar type requested"); | |
168 return error_mark_node; | |
169 } |