1 /* Language-level data type conversion for GNU C.
2 Copyright (C) 1987, 1988, 1991, 1998, 2002, 2007
3 Free Software Foundation, Inc.
5 This file is part of GCC.
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
9 Software Foundation; either version 2, or (at your option) any later
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
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
23 /* This file contains the functions for converting C expressions
24 to different data types. The only entry point is `convert'.
25 Every language front end must have a `convert' function
26 but what kind of conversions it does will depend on the language. */
28 /* copied from the f77 frontend I think */
30 /* copied from c-convert.c without significant modification*/
31 /* Change of width--truncation and extension of integers or reals--
32 is represented with NOP_EXPR. Proper functioning of many things
33 assumes that no other conversions can be NOP_EXPRs.
36 /* I've added support for WITH_RECORD_EXPR. */
40 #include "coretypes.h"
49 Conversion between integer and pointer is represented with CONVERT_EXPR.
50 Converting integer to real uses FLOAT_EXPR
51 and real to integer uses FIX_TRUNC_EXPR.
53 Here is a list of all the functions that assume that widening and
54 narrowing is always done with a NOP_EXPR:
55 In convert.c, convert_to_integer.
56 In c-typeck.c, build_binary_op (boolean ops), and
57 c_common_truthvalue_conversion.
58 In expr.c: expand_expr, for operands of a MULT_EXPR.
59 In fold-const.c: fold.
60 In tree.c: get_narrower and get_unwidened. */
62 /* Subroutines of `convert'. */
65 /* Create an expression whose value is that of EXPR,
66 converted to type TYPE. The TREE_TYPE of the value
67 is always TYPE. This function implements all reasonable
68 conversions; callers should filter out those that are
69 not permitted by the language being compiled. */
70 /* We are assuming that given a SIMPLE val, the result will be a SIMPLE rhs.
71 If this is not the case, we will abort with an internal error. */
73 convert (tree type
, tree expr
)
76 enum tree_code code
= TREE_CODE (type
);
78 if (type
== TREE_TYPE (expr
)
79 || TREE_CODE (expr
) == ERROR_MARK
80 || code
== ERROR_MARK
|| TREE_CODE (TREE_TYPE (expr
)) == ERROR_MARK
)
83 if (TYPE_MAIN_VARIANT (type
) == TYPE_MAIN_VARIANT (TREE_TYPE (expr
)))
84 return fold_build1 (NOP_EXPR
, type
, expr
);
85 if (TREE_CODE (TREE_TYPE (expr
)) == ERROR_MARK
)
86 return error_mark_node
;
87 if (TREE_CODE (TREE_TYPE (expr
)) == VOID_TYPE
)
89 error ("void value not ignored as it ought to be");
90 return error_mark_node
;
92 if (code
== VOID_TYPE
)
93 return build1 (CONVERT_EXPR
, type
, e
);
95 /* This is incorrect. A truncation can't be stripped this way.
96 Extensions will be stripped by the use of get_unwidened. */
97 if (TREE_CODE (expr
) == NOP_EXPR
)
98 return convert (type
, TREE_OPERAND (expr
, 0));
100 if (code
== INTEGER_TYPE
|| code
== ENUMERAL_TYPE
)
101 return fold (convert_to_integer (type
, e
));
102 if (code
== BOOLEAN_TYPE
)
104 e
= gfc_truthvalue_conversion (e
);
106 /* If we have a NOP_EXPR, we must fold it here to avoid
107 infinite recursion between fold () and convert (). */
108 if (TREE_CODE (e
) == NOP_EXPR
)
109 return fold_build1 (NOP_EXPR
, type
, TREE_OPERAND (e
, 0));
111 return fold_build1 (NOP_EXPR
, type
, e
);
113 if (code
== POINTER_TYPE
|| code
== REFERENCE_TYPE
)
114 return fold (convert_to_pointer (type
, e
));
115 if (code
== REAL_TYPE
)
116 return fold (convert_to_real (type
, e
));
117 if (code
== COMPLEX_TYPE
)
118 return fold (convert_to_complex (type
, e
));
119 if (code
== VECTOR_TYPE
)
120 return fold (convert_to_vector (type
, e
));
122 error ("conversion to non-scalar type requested");
123 return error_mark_node
;