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0e48b5a2 | 1 | /* Language-level data type conversion for GNU C. |
99dee823 | 2 | Copyright (C) 1987-2021 Free Software Foundation, Inc. |
0e48b5a2 | 3 | |
1322177d | 4 | This file is part of GCC. |
0e48b5a2 | 5 | |
1322177d LB |
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 | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 9 | version. |
0e48b5a2 | 10 | |
1322177d LB |
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. | |
0e48b5a2 RS |
15 | |
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
0e48b5a2 RS |
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" | |
c5c76735 | 27 | #include "system.h" |
4977bab6 | 28 | #include "coretypes.h" |
2adfab87 | 29 | #include "target.h" |
85498824 | 30 | #include "c-tree.h" |
2adfab87 | 31 | #include "convert.h" |
e57e265b | 32 | #include "langhooks.h" |
8f94a8c4 | 33 | #include "ubsan.h" |
314e6352 ML |
34 | #include "stringpool.h" |
35 | #include "attribs.h" | |
45b2222a | 36 | #include "asan.h" |
0e48b5a2 RS |
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: | |
10055ae2 | 48 | In convert.c, convert_to_integer. |
78ef5b89 NB |
49 | In c-typeck.c, build_binary_op (boolean ops), and |
50 | c_common_truthvalue_conversion. | |
0e48b5a2 RS |
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 | \f | |
55 | /* Subroutines of `convert'. */ | |
56 | ||
0e48b5a2 | 57 | |
0e48b5a2 RS |
58 | \f |
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 | |
35b1a6fa | 66 | convert (tree type, tree expr) |
0e48b5a2 | 67 | { |
b3694847 SS |
68 | tree e = expr; |
69 | enum tree_code code = TREE_CODE (type); | |
4de67c26 | 70 | const char *invalid_conv_diag; |
4d84fe7c | 71 | tree ret; |
db3927fb | 72 | location_t loc = EXPR_LOCATION (expr); |
0e48b5a2 | 73 | |
4de67c26 | 74 | if (type == error_mark_node |
7a0ca710 | 75 | || error_operand_p (expr)) |
4de67c26 JM |
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)) | |
0e48b5a2 | 86 | return expr; |
40449a90 SL |
87 | ret = targetm.convert_to_type (type, expr); |
88 | if (ret) | |
89 | return ret; | |
17aec3eb | 90 | |
928c19bb JM |
91 | STRIP_TYPE_NOPS (e); |
92 | ||
d409320c JJ |
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)) | |
db3927fb | 96 | return fold_convert_loc (loc, type, expr); |
0e48b5a2 RS |
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 | } | |
4d84fe7c JM |
104 | |
105 | switch (code) | |
106 | { | |
107 | case VOID_TYPE: | |
db3927fb | 108 | return fold_convert_loc (loc, type, e); |
4d84fe7c JM |
109 | |
110 | case INTEGER_TYPE: | |
111 | case ENUMERAL_TYPE: | |
45b2222a | 112 | if (sanitize_flags_p (SANITIZE_FLOAT_CAST) |
f34ebeb2 | 113 | && current_function_decl != NULL_TREE |
8f94a8c4 | 114 | && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE |
45b2222a | 115 | && COMPLETE_TYPE_P (type)) |
8f94a8c4 | 116 | { |
b2fa0a8b | 117 | expr = save_expr (expr); |
6d939173 | 118 | expr = c_fully_fold (expr, false, NULL); |
6b131d5b | 119 | tree check = ubsan_instrument_float_cast (loc, type, expr); |
8f94a8c4 | 120 | expr = fold_build1 (FIX_TRUNC_EXPR, type, expr); |
6b131d5b | 121 | if (check == NULL_TREE) |
8f94a8c4 JJ |
122 | return expr; |
123 | return fold_build2 (COMPOUND_EXPR, TREE_TYPE (expr), check, expr); | |
124 | } | |
4d84fe7c JM |
125 | ret = convert_to_integer (type, e); |
126 | goto maybe_fold; | |
127 | ||
128 | case BOOLEAN_TYPE: | |
db3927fb AH |
129 | return fold_convert_loc |
130 | (loc, type, c_objc_common_truthvalue_conversion (input_location, expr)); | |
4d84fe7c JM |
131 | |
132 | case POINTER_TYPE: | |
133 | case REFERENCE_TYPE: | |
134 | ret = convert_to_pointer (type, e); | |
135 | goto maybe_fold; | |
136 | ||
137 | case REAL_TYPE: | |
138 | ret = convert_to_real (type, e); | |
139 | goto maybe_fold; | |
140 | ||
141 | case FIXED_POINT_TYPE: | |
142 | ret = convert_to_fixed (type, e); | |
143 | goto maybe_fold; | |
144 | ||
145 | case COMPLEX_TYPE: | |
146 | ret = convert_to_complex (type, e); | |
147 | goto maybe_fold; | |
148 | ||
149 | case VECTOR_TYPE: | |
f486280c RS |
150 | if (gnu_vector_type_p (type) |
151 | || gnu_vector_type_p (TREE_TYPE (e)) | |
152 | /* Allow conversions between compatible non-GNU vector types | |
153 | when -flax-vector-conversions is passed. The whole purpose | |
154 | of the option is to bend the normal type rules and accept | |
155 | nonconforming code. */ | |
156 | || (flag_lax_vector_conversions | |
157 | && VECTOR_TYPE_P (TREE_TYPE (e)) | |
158 | && vector_types_convertible_p (type, TREE_TYPE (e), false))) | |
159 | { | |
160 | ret = convert_to_vector (type, e); | |
161 | goto maybe_fold; | |
162 | } | |
163 | break; | |
4d84fe7c JM |
164 | |
165 | case RECORD_TYPE: | |
166 | case UNION_TYPE: | |
167 | if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) | |
168 | return e; | |
169 | break; | |
170 | ||
171 | default: | |
172 | break; | |
173 | ||
174 | maybe_fold: | |
175 | if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR) | |
176 | ret = fold (ret); | |
177 | return ret; | |
178 | } | |
0e48b5a2 RS |
179 | |
180 | error ("conversion to non-scalar type requested"); | |
181 | return error_mark_node; | |
182 | } |