1 /* Language-level data type conversion for GNU C.
2 Copyright (C) 1987-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>. */
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. */
28 #include "coretypes.h"
33 #include "c-family/c-common.h"
35 #include "langhooks.h"
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.
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.
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. */
55 /* Subroutines of `convert'. */
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. */
66 convert (tree type
, tree expr
)
69 enum tree_code code
= TREE_CODE (type
);
70 const char *invalid_conv_diag
;
72 location_t loc
= EXPR_LOCATION (expr
);
74 if (type
== error_mark_node
75 || error_operand_p (expr
))
76 return error_mark_node
;
78 if ((invalid_conv_diag
79 = targetm
.invalid_conversion (TREE_TYPE (expr
), type
)))
81 error (invalid_conv_diag
);
82 return error_mark_node
;
85 if (type
== TREE_TYPE (expr
))
87 ret
= targetm
.convert_to_type (type
, expr
);
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
)
101 error ("void value not ignored as it ought to be");
102 return error_mark_node
;
108 return fold_convert_loc (loc
, type
, e
);
112 ret
= convert_to_integer (type
, e
);
116 return fold_convert_loc
117 (loc
, type
, c_objc_common_truthvalue_conversion (input_location
, expr
));
121 ret
= convert_to_pointer (type
, e
);
125 ret
= convert_to_real (type
, e
);
128 case FIXED_POINT_TYPE
:
129 ret
= convert_to_fixed (type
, e
);
133 /* If converting from COMPLEX_TYPE to a different COMPLEX_TYPE
134 and e is not COMPLEX_EXPR, convert_to_complex uses save_expr,
135 but for the C FE c_save_expr needs to be called instead. */
136 if (TREE_CODE (TREE_TYPE (e
)) == COMPLEX_TYPE
)
138 if (TREE_CODE (e
) != COMPLEX_EXPR
)
140 tree subtype
= TREE_TYPE (type
);
141 tree elt_type
= TREE_TYPE (TREE_TYPE (e
));
143 if (in_late_binary_op
)
148 = fold_build2_loc (loc
, COMPLEX_EXPR
, type
,
150 fold_build1 (REALPART_EXPR
,
153 fold_build1 (IMAGPART_EXPR
,
158 ret
= convert_to_complex (type
, e
);
162 ret
= convert_to_vector (type
, e
);
167 if (lang_hooks
.types_compatible_p (type
, TREE_TYPE (expr
)))
175 if (TREE_CODE (ret
) != C_MAYBE_CONST_EXPR
)
180 error ("conversion to non-scalar type requested");
181 return error_mark_node
;