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Diffstat (limited to 'gdb/hash-traits.h')
-rw-r--r-- | gdb/hash-traits.h | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/gdb/hash-traits.h b/gdb/hash-traits.h new file mode 100644 index 0000000..c31edc96 --- /dev/null +++ b/gdb/hash-traits.h @@ -0,0 +1,322 @@ +/* Traits for hashable types. + Copyright (C) 2014-2019 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 3, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +<http://www.gnu.org/licenses/>. */ + +#ifndef hash_traits_h +#define hash_traits_h + +/* Helpful type for removing with free. */ + +template <typename Type> +struct typed_free_remove +{ + static inline void remove (Type *p); +}; + + +/* Remove with free. */ + +template <typename Type> +inline void +typed_free_remove <Type>::remove (Type *p) +{ + free (p); +} + +/* Helpful type for removing with delete. */ + +template <typename Type> +struct typed_delete_remove +{ + static inline void remove (Type *p); +}; + + +/* Remove with delete. */ + +template <typename Type> +inline void +typed_delete_remove <Type>::remove (Type *p) +{ + delete p; +} + +/* Helpful type for a no-op remove. */ + +template <typename Type> +struct typed_noop_remove +{ + static inline void remove (Type &); +}; + + +/* Remove doing nothing. */ + +template <typename Type> +inline void +typed_noop_remove <Type>::remove (Type &) +{ +} + + +/* Hasher for integer type Type in which Empty is a spare value that can be + used to mark empty slots. If Deleted != Empty then Deleted is another + spare value that can be used for deleted slots; if Deleted == Empty then + hash table entries cannot be deleted. */ + +template <typename Type, Type Empty, Type Deleted = Empty> +struct int_hash : typed_noop_remove <Type> +{ + typedef Type value_type; + typedef Type compare_type; + + static inline hashval_t hash (value_type); + static inline bool equal (value_type existing, value_type candidate); + static inline void mark_deleted (Type &); + static inline void mark_empty (Type &); + static inline bool is_deleted (Type); + static inline bool is_empty (Type); +}; + +template <typename Type, Type Empty, Type Deleted> +inline hashval_t +int_hash <Type, Empty, Deleted>::hash (value_type x) +{ + return x; +} + +template <typename Type, Type Empty, Type Deleted> +inline bool +int_hash <Type, Empty, Deleted>::equal (value_type x, value_type y) +{ + return x == y; +} + +template <typename Type, Type Empty, Type Deleted> +inline void +int_hash <Type, Empty, Deleted>::mark_deleted (Type &x) +{ + gdb_assert (Empty != Deleted); + x = Deleted; +} + +template <typename Type, Type Empty, Type Deleted> +inline void +int_hash <Type, Empty, Deleted>::mark_empty (Type &x) +{ + x = Empty; +} + +template <typename Type, Type Empty, Type Deleted> +inline bool +int_hash <Type, Empty, Deleted>::is_deleted (Type x) +{ + return Empty != Deleted && x == Deleted; +} + +template <typename Type, Type Empty, Type Deleted> +inline bool +int_hash <Type, Empty, Deleted>::is_empty (Type x) +{ + return x == Empty; +} + +/* Pointer hasher based on pointer equality. Other types of pointer hash + can inherit this and override the hash and equal functions with some + other form of equality (such as string equality). */ + +template <typename Type> +struct pointer_hash +{ + typedef Type *value_type; + typedef Type *compare_type; + + static inline hashval_t hash (const value_type &); + static inline bool equal (const value_type &existing, + const compare_type &candidate); + static inline void mark_deleted (Type *&); + static inline void mark_empty (Type *&); + static inline bool is_deleted (Type *); + static inline bool is_empty (Type *); +}; + +template <typename Type> +inline hashval_t +pointer_hash <Type>::hash (const value_type &candidate) +{ + /* This is a really poor hash function, but it is what the current code uses, + so I am reusing it to avoid an additional axis in testing. */ + return (hashval_t) ((intptr_t)candidate >> 3); +} + +template <typename Type> +inline bool +pointer_hash <Type>::equal (const value_type &existing, + const compare_type &candidate) +{ + return existing == candidate; +} + +template <typename Type> +inline void +pointer_hash <Type>::mark_deleted (Type *&e) +{ + e = reinterpret_cast<Type *> (1); +} + +template <typename Type> +inline void +pointer_hash <Type>::mark_empty (Type *&e) +{ + e = NULL; +} + +template <typename Type> +inline bool +pointer_hash <Type>::is_deleted (Type *e) +{ + return e == reinterpret_cast<Type *> (1); +} + +template <typename Type> +inline bool +pointer_hash <Type>::is_empty (Type *e) +{ + return e == NULL; +} + +/* Hasher for "const char *" strings, using string rather than pointer + equality. */ + +struct string_hash : pointer_hash <const char> +{ + static inline hashval_t hash (const char *); + static inline bool equal (const char *, const char *); +}; + +inline hashval_t +string_hash::hash (const char *id) +{ + return htab_hash_string (id); +} + +inline bool +string_hash::equal (const char *id1, const char *id2) +{ + return strcmp (id1, id2) == 0; +} + +/* Traits for pointer elements that should not be freed when an element + is deleted. */ + +template <typename T> +struct nofree_ptr_hash : pointer_hash <T>, typed_noop_remove <T *> {}; + +/* Traits for pointer elements that should be freed via free() when an + element is deleted. */ + +template <typename T> +struct free_ptr_hash : pointer_hash <T>, typed_free_remove <T> {}; + +/* Traits for pointer elements that should be freed via delete operand when an + element is deleted. */ + +template <typename T> +struct delete_ptr_hash : pointer_hash <T>, typed_delete_remove <T> {}; + +/* Traits for string elements that should not be freed when an element + is deleted. */ + +struct nofree_string_hash : string_hash, typed_noop_remove <const char *> {}; + +/* Traits for pairs of values, using the first to record empty and + deleted slots. */ + +template <typename T1, typename T2> +struct pair_hash +{ + typedef std::pair <typename T1::value_type, + typename T2::value_type> value_type; + typedef std::pair <typename T1::compare_type, + typename T2::compare_type> compare_type; + + static inline hashval_t hash (const value_type &); + static inline bool equal (const value_type &, const compare_type &); + static inline void remove (value_type &); + static inline void mark_deleted (value_type &); + static inline void mark_empty (value_type &); + static inline bool is_deleted (const value_type &); + static inline bool is_empty (const value_type &); +}; + +template <typename T1, typename T2> +inline hashval_t +pair_hash <T1, T2>::hash (const value_type &x) +{ + return iterative_hash_hashval_t (T1::hash (x.first), T2::hash (x.second)); +} + +template <typename T1, typename T2> +inline bool +pair_hash <T1, T2>::equal (const value_type &x, const compare_type &y) +{ + return T1::equal (x.first, y.first) && T2::equal (x.second, y.second); +} + +template <typename T1, typename T2> +inline void +pair_hash <T1, T2>::remove (value_type &x) +{ + T1::remove (x.first); + T2::remove (x.second); +} + +template <typename T1, typename T2> +inline void +pair_hash <T1, T2>::mark_deleted (value_type &x) +{ + T1::mark_deleted (x.first); +} + +template <typename T1, typename T2> +inline void +pair_hash <T1, T2>::mark_empty (value_type &x) +{ + T1::mark_empty (x.first); +} + +template <typename T1, typename T2> +inline bool +pair_hash <T1, T2>::is_deleted (const value_type &x) +{ + return T1::is_deleted (x.first); +} + +template <typename T1, typename T2> +inline bool +pair_hash <T1, T2>::is_empty (const value_type &x) +{ + return T1::is_empty (x.first); +} + +template <typename T> struct default_hash_traits : T {}; + +template <typename T> +struct default_hash_traits <T *> : pointer_hash <T> {}; + +#endif |