C++-ify bcache

This somewhat C++-ifies bcache.  It replaces bcache_xmalloc and
bcache_xfree with constructors; changes some functions into methods;
and changes various structures to include a bcache directly (as
opposed to a pointer to a bcache).

Tested by the buildbot.

gdb/ChangeLog
2019-03-07  Tom Tromey  <tom@tromey.com>

	* symmisc.c (print_symbol_bcache_statistics): Update.
	(print_objfile_statistics): Update.
	* symfile.c (allocate_symtab): Update.
	* stabsread.c: Don't include bcache.h.
	* psymtab.h (struct psymbol_bcache): Don't declare.
	(class psymtab_storage) <psymbol_cache>: Now a bcache.
	(psymbol_bcache_init, psymbol_bcache_free)
	(psymbol_bcache_get_bcache): Don't declare.
	* psymtab.c (struct psymbol_bcache): Remove.
	(psymtab_storage::psymtab_storage): Update.
	(psymtab_storage::~psymtab_storage): Update.
	(psymbol_bcache_init, psymbol_bcache_free)
	(psymbol_bcache_get_bcache, psymbol_bcache_full): Remove.
	(add_psymbol_to_bcache): Update.
	(allocate_psymtab): Update.
	* objfiles.h (struct objfile_per_bfd_storage) <filename_cache,
	macro_cache>: No longer pointers.
	* objfiles.c (get_objfile_bfd_data): Don't call bcache_xmalloc.
	(free_objfile_per_bfd_storage): Don't call bcache_xfree.
	* macrotab.c (macro_bcache): Update.
	* macroexp.c: Don't include bcache.h.
	* gdbtypes.c (check_types_worklist): Update.
	(types_deeply_equal): Remove TRY/CATCH.  Update.
	* elfread.c (elf_symtab_read): Update.
	* dwarf2read.c: Don't include bcache.h.
	* buildsym.c (buildsym_compunit::get_macro_table): Update.
	* bcache.h (bcache, bcache_full, bcache_xffree, bcache_xmalloc)
	(print_bcache_statistics, bcache_memory_used): Don't declare.
	(struct bcache): Move from bcache.c.  Add constructor, destructor,
	methods.  Rename all data members.
	* bcache.c (struct bcache): Move to bcache.h.
	(bcache::expand_hash_table): Rename from expand_hash_table.
	(bcache): Remove.
	(bcache::insert): Rename from bcache_full.
	(bcache::compare): Rename from bcache_compare.
	(bcache_xmalloc): Remove.
	(bcache::~bcache): Rename from bcache_xfree.
	(bcache::print_statistics): Rename from print_bcache_statistics.
	(bcache::memory_used): Rename from bcache_memory_used.

1 files changed, 80 insertions, 32 deletions

diff --git a/gdb/bcache.h b/gdb/bcache.h
index aa014792..15dcc63 100644
--- a/gdb/bcache.h
+++ b/gdb/bcache.h
@@ -136,41 +136,89 @@
   
 */
 
-
-struct bcache;
-
-/* Find a copy of the LENGTH bytes at ADDR in BCACHE.  If BCACHE has
-   never seen those bytes before, add a copy of them to BCACHE.  In
-   either case, return a pointer to BCACHE's copy of that string.
-   Since the cached value is ment to be read-only, return a const
-   buffer.  */
-extern const void *bcache (const void *addr, int length,
-			   struct bcache *bcache);
-
-/* Like bcache, but if ADDED is not NULL, set *ADDED to true if the
-   bytes were newly added to the cache, or to false if the bytes were
-   found in the cache.  */
-extern const void *bcache_full (const void *addr, int length,
-				struct bcache *bcache, int *added);
-
-/* Free all the storage used by BCACHE.  */
-extern void bcache_xfree (struct bcache *bcache);
-
-/* Create a new bcache object.  */
-extern struct bcache *bcache_xmalloc (
-    unsigned long (*hash_function)(const void *, int length),
-    int (*compare_function)(const void *, const void *, int length));
-
-/* Print statistics on BCACHE's memory usage and efficacity at
-   eliminating duplication.  TYPE should be a string describing the
-   kind of data BCACHE holds.  Statistics are printed using
-   `printf_filtered' and its ilk.  */
-extern void print_bcache_statistics (struct bcache *bcache, const char *type);
-extern int bcache_memory_used (struct bcache *bcache);
+struct bstring;
 
 /* The hash functions */
-extern unsigned long hash(const void *addr, int length);
+extern unsigned long hash (const void *addr, int length);
 extern unsigned long hash_continue (const void *addr, int length,
                                     unsigned long h);
 
+struct bcache
+{
+  /* Allocate a bcache.  HASH_FN and COMPARE_FN can be used to pass in
+     custom hash, and compare functions to be used by this bcache.  If
+     HASH_FUNCTION is NULL hash() is used and if COMPARE_FUNCTION is
+     NULL memcmp() is used.  */
+
+  explicit bcache (unsigned long (*hash_fn)(const void *,
+					    int length) = nullptr,
+		   int (*compare_fn)(const void *, const void *,
+				     int length) = nullptr)
+    : m_hash_function (hash_fn == nullptr ? hash : hash_fn),
+      m_compare_function (compare_fn == nullptr ? compare : compare_fn)
+  {
+  }
+
+  ~bcache ();
+
+  /* Find a copy of the LENGTH bytes at ADDR in BCACHE.  If BCACHE has
+     never seen those bytes before, add a copy of them to BCACHE.  In
+     either case, return a pointer to BCACHE's copy of that string.
+     Since the cached value is ment to be read-only, return a const
+     buffer.  If ADDED is not NULL, set *ADDED to true if the bytes
+     were newly added to the cache, or to false if the bytes were
+     found in the cache.  */
+
+  const void *insert (const void *addr, int length, int *added = nullptr);
+
+  /* Print statistics on this bcache's memory usage and efficacity at
+     eliminating duplication.  TYPE should be a string describing the
+     kind of data this bcache holds.  Statistics are printed using
+     `printf_filtered' and its ilk.  */
+  void print_statistics (const char *type);
+  int memory_used ();
+
+private:
+
+  /* All the bstrings are allocated here.  */
+  struct obstack m_cache {};
+
+  /* How many hash buckets we're using.  */
+  unsigned int m_num_buckets = 0;
+
+  /* Hash buckets.  This table is allocated using malloc, so when we
+     grow the table we can return the old table to the system.  */
+  struct bstring **m_bucket = nullptr;
+
+  /* Statistics.  */
+  unsigned long m_unique_count = 0;	/* number of unique strings */
+  long m_total_count = 0;	/* total number of strings cached, including dups */
+  long m_unique_size = 0;	/* size of unique strings, in bytes */
+  long m_total_size = 0;      /* total number of bytes cached, including dups */
+  long m_structure_size = 0;	/* total size of bcache, including infrastructure */
+  /* Number of times that the hash table is expanded and hence
+     re-built, and the corresponding number of times that a string is
+     [re]hashed as part of entering it into the expanded table.  The
+     total number of hashes can be computed by adding TOTAL_COUNT to
+     expand_hash_count.  */
+  unsigned long m_expand_count = 0;
+  unsigned long m_expand_hash_count = 0;
+  /* Number of times that the half-hash compare hit (compare the upper
+     16 bits of hash values) hit, but the corresponding combined
+     length/data compare missed.  */
+  unsigned long m_half_hash_miss_count = 0;
+
+  /* Hash function to be used for this bcache object.  */
+  unsigned long (*m_hash_function)(const void *addr, int length);
+
+  /* Compare function to be used for this bcache object.  */
+  int (*m_compare_function)(const void *, const void *, int length);
+
+  /* Default compare function.  */
+  static int compare (const void *addr1, const void *addr2, int length);
+
+  /* Expand the hash table.  */
+  void expand_hash_table ();
+};
+
 #endif /* BCACHE_H */