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0e48b5a2 | 1 | /* Language-level data type conversion for GNU C. |
4283012f | 2 | Copyright (C) 1987, 1988, 1991, 1998 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 | |
8 | Software Foundation; either version 2, or (at your option) any later | |
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 | |
1322177d LB |
17 | along with GCC; see the file COPYING. If not, write to the Free |
18 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
19 | 02111-1307, USA. */ | |
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" |
0e48b5a2 RS |
29 | #include "tree.h" |
30 | #include "flags.h" | |
10055ae2 | 31 | #include "convert.h" |
5f6da302 | 32 | #include "toplev.h" |
0e48b5a2 RS |
33 | |
34 | /* Change of width--truncation and extension of integers or reals-- | |
35 | is represented with NOP_EXPR. Proper functioning of many things | |
36 | assumes that no other conversions can be NOP_EXPRs. | |
37 | ||
38 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
39 | Converting integer to real uses FLOAT_EXPR | |
40 | and real to integer uses FIX_TRUNC_EXPR. | |
41 | ||
42 | Here is a list of all the functions that assume that widening and | |
43 | narrowing is always done with a NOP_EXPR: | |
10055ae2 | 44 | In convert.c, convert_to_integer. |
0e48b5a2 RS |
45 | In c-typeck.c, build_binary_op (boolean ops), and truthvalue_conversion. |
46 | In expr.c: expand_expr, for operands of a MULT_EXPR. | |
47 | In fold-const.c: fold. | |
48 | In tree.c: get_narrower and get_unwidened. */ | |
49 | \f | |
50 | /* Subroutines of `convert'. */ | |
51 | ||
0e48b5a2 | 52 | |
0e48b5a2 RS |
53 | \f |
54 | /* Create an expression whose value is that of EXPR, | |
55 | converted to type TYPE. The TREE_TYPE of the value | |
56 | is always TYPE. This function implements all reasonable | |
57 | conversions; callers should filter out those that are | |
58 | not permitted by the language being compiled. */ | |
59 | ||
60 | tree | |
61 | convert (type, expr) | |
62 | tree type, expr; | |
63 | { | |
b3694847 SS |
64 | tree e = expr; |
65 | enum tree_code code = TREE_CODE (type); | |
0e48b5a2 | 66 | |
412a4297 | 67 | if (type == TREE_TYPE (expr) |
17aec3eb RK |
68 | || TREE_CODE (expr) == ERROR_MARK |
69 | || code == ERROR_MARK || TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) | |
0e48b5a2 | 70 | return expr; |
17aec3eb | 71 | |
412a4297 | 72 | if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) |
542bc952 | 73 | return fold (build1 (NOP_EXPR, type, expr)); |
0e48b5a2 RS |
74 | if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) |
75 | return error_mark_node; | |
76 | if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) | |
77 | { | |
78 | error ("void value not ignored as it ought to be"); | |
79 | return error_mark_node; | |
80 | } | |
81 | if (code == VOID_TYPE) | |
82 | return build1 (CONVERT_EXPR, type, e); | |
83 | #if 0 | |
84 | /* This is incorrect. A truncation can't be stripped this way. | |
85 | Extensions will be stripped by the use of get_unwidened. */ | |
86 | if (TREE_CODE (expr) == NOP_EXPR) | |
87 | return convert (type, TREE_OPERAND (expr, 0)); | |
88 | #endif | |
89 | if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) | |
90 | return fold (convert_to_integer (type, e)); | |
19552aa5 | 91 | if (code == BOOLEAN_TYPE) |
c3cd9c8b JM |
92 | { |
93 | tree t = truthvalue_conversion (expr); | |
94 | /* If truthvalue_conversion returns a NOP_EXPR, we must fold it here | |
95 | to avoid infinite recursion between fold () and convert (). */ | |
96 | if (TREE_CODE (t) == NOP_EXPR) | |
97 | return fold (build1 (NOP_EXPR, type, TREE_OPERAND (t, 0))); | |
98 | else | |
99 | return fold (build1 (NOP_EXPR, type, t)); | |
100 | } | |
98d64f69 | 101 | if (code == POINTER_TYPE || code == REFERENCE_TYPE) |
0e48b5a2 RS |
102 | return fold (convert_to_pointer (type, e)); |
103 | if (code == REAL_TYPE) | |
104 | return fold (convert_to_real (type, e)); | |
c050422f RS |
105 | if (code == COMPLEX_TYPE) |
106 | return fold (convert_to_complex (type, e)); | |
0b4565c9 BS |
107 | if (code == VECTOR_TYPE) |
108 | return fold (convert_to_vector (type, e)); | |
0e48b5a2 RS |
109 | |
110 | error ("conversion to non-scalar type requested"); | |
111 | return error_mark_node; | |
112 | } |