1 /* Traits for hashable types.
2 Copyright (C) 2014-2015 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/>. */
23 /* Helpful type for removing with free. */
25 template <typename Type
>
26 struct typed_free_remove
28 static inline void remove (Type
*p
);
32 /* Remove with free. */
34 template <typename Type
>
36 typed_free_remove
<Type
>::remove (Type
*p
)
42 /* Helpful type for a no-op remove. */
44 template <typename Type
>
45 struct typed_noop_remove
47 static inline void remove (Type
*p
);
51 /* Remove doing nothing. */
53 template <typename Type
>
55 typed_noop_remove
<Type
>::remove (Type
*p ATTRIBUTE_UNUSED
)
60 /* Pointer hash with a no-op remove method. */
62 template <typename Type
>
63 struct pointer_hash
: typed_noop_remove
<Type
>
65 typedef Type
*value_type
;
66 typedef Type
*compare_type
;
68 static inline hashval_t
hash (const value_type
&);
70 static inline bool equal (const value_type
&existing
,
71 const compare_type
&candidate
);
74 template <typename Type
>
76 pointer_hash
<Type
>::hash (const value_type
&candidate
)
78 /* This is a really poor hash function, but it is what the current code uses,
79 so I am reusing it to avoid an additional axis in testing. */
80 return (hashval_t
) ((intptr_t)candidate
>> 3);
83 template <typename Type
>
85 pointer_hash
<Type
>::equal (const value_type
&existing
,
86 const compare_type
&candidate
)
88 return existing
== candidate
;
91 /* Hasher for entry in gc memory. */
97 typedef T compare_type
;
99 static void remove (T
) {}
104 extern void gt_ggc_mx (T
&);
111 extern void gt_pch_nx (T
&);
116 pch_nx (T
&p
, gt_pointer_operator op
, void *cookie
)
122 /* Hasher for cache entry in gc memory. */
125 struct ggc_cache_hasher
127 typedef T value_type
;
128 typedef T compare_type
;
130 static void remove (T
&) {}
132 /* Entries are weakly held because this is for caches. */
134 static void ggc_mx (T
&) {}
139 extern void gt_pch_nx (T
&);
144 pch_nx (T
&p
, gt_pointer_operator op
, void *cookie
)
150 keep_cache_entry (T
&e
)
152 return ggc_marked_p (e
) ? -1 : 0;