Fork GCC's hash-table.h for use in GDBusers/cbiesinger/hashtable

And use it at one callsite in dwarf2read.

1 files changed, 322 insertions, 0 deletions

diff --git a/gdb/hash-traits.h b/gdb/hash-traits.h
new file mode 100644
index 00000000000..c31edc96039
--- /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