Temporarily revert symbol lookup cache.

clear_symtab_users calls breakpoint_re_set before
observer_notify_new_objfile(NULL), and thus symbol lookup
done during breakpoint_re_set will see a stale cache.

Presumably we just need to move the call to observer_notify_new_objfile(NULL)
to before breakpoint_re_set, but need to check for other such issues,
and 7.9 is scheduled to branch tomorrow.

Reverts commits:
b2fb95e006c29e2cbe4b30523879fe3640f906ad
400678a494713abf8f7ea2367f213109a2c4b886
d98b9ccbccf36563dad92f6093a93655b38bc51b
77087adf50cedf78cc216ac6eb3b2863839d713c

gdb/ChangeLog:

	* symtab.c (eq_symbol_entry): Use SYMBOL_SEARCH_NAME and
	symbol_matches_domain for symbol comparisons.

	* symtab.c (symbol_cache_mark_found): Improve function comment.
	Rename parameter objfile to objfile_context.
	(symbol_cache_mark_not_found): Improve function comment.

	Add symbol lookup cache.
	* NEWS: Document new options and commands.
	* symtab.c (symbol_cache_key): New static global.
	(DEFAULT_SYMBOL_CACHE_SIZE, MAX_SYMBOL_CACHE_SIZE): New macros.
	(SYMBOL_LOOKUP_FAILED): New macro.
	(symbol_cache_slot_state): New enum.
	(block_symbol_cache): New struct.
	(symbol_cache): New struct.
	(new_symbol_cache_size, symbol_cache_size): New static globals.
	(hash_symbol_entry, eq_symbol_entry): New functions.
	(symbol_cache_byte_size, resize_symbol_cache): New functions.
	(make_symbol_cache, free_symbol_cache): New functions.
	(get_symbol_cache, symbol_cache_cleanup): New function.
	(set_symbol_cache_size, set_symbol_cache_size_handler): New functions.
	(symbol_cache_lookup, symbol_cache_clear_slot): New function.
	(symbol_cache_mark_found, symbol_cache_mark_not_found): New functions.
	(symbol_cache_flush, symbol_cache_dump): New functions.
	(maintenance_print_symbol_cache): New function.
	(maintenance_flush_symbol_cache): New function.
	(symbol_cache_stats): New function.
	(maintenance_print_symbol_cache_statistics): New function.
	(symtab_new_objfile_observer): New function.
	(symtab_free_objfile_observer): New function.
	(lookup_static_symbol, lookup_global_symbol): Use symbol cache.
	(_initialize_symtab): Init symbol_cache_key.  New parameter
	maint symbol-cache-size.  New maint commands print symbol-cache,
	print symbol-cache-statistics, flush-symbol-cache.
	Install new_objfile, free_objfile observers.

gdb/doc/ChangeLog:

	* gdb.texinfo (Symbols): Document new commands
	"maint print symbol-cache", "maint print symbol-cache-statistics",
	"maint flush-symbol-cache".  Document new option
	"maint set symbol-cache-size".

5 files changed, 14 insertions, 828 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 79db75c..75b286c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -14,48 +14,6 @@
 	* inf-ptrace.c (inf_ptrace_follow_fork): Adjust now that
 	inferior_thread is a function.
 
-2015-01-11  Doug Evans  <xdje42@gmail.com>
-
-	* symtab.c (eq_symbol_entry): Use SYMBOL_SEARCH_NAME and
-	symbol_matches_domain for symbol comparisons.
-
-2015-01-11  Doug Evans  <xdje42@gmail.com>
-
-	* symtab.c (symbol_cache_mark_found): Improve function comment.
-	Rename parameter objfile to objfile_context.
-	(symbol_cache_mark_not_found): Improve function comment.
-
-2015-01-10  Doug Evans  <xdje42@gmail.com>
-
-	Add symbol lookup cache.
-	* NEWS: Document new options and commands.
-	* symtab.c (symbol_cache_key): New static global.
-	(DEFAULT_SYMBOL_CACHE_SIZE, MAX_SYMBOL_CACHE_SIZE): New macros.
-	(SYMBOL_LOOKUP_FAILED): New macro.
-	(symbol_cache_slot_state): New enum.
-	(block_symbol_cache): New struct.
-	(symbol_cache): New struct.
-	(new_symbol_cache_size, symbol_cache_size): New static globals.
-	(hash_symbol_entry, eq_symbol_entry): New functions.
-	(symbol_cache_byte_size, resize_symbol_cache): New functions.
-	(make_symbol_cache, free_symbol_cache): New functions.
-	(get_symbol_cache, symbol_cache_cleanup): New function.
-	(set_symbol_cache_size, set_symbol_cache_size_handler): New functions.
-	(symbol_cache_lookup, symbol_cache_clear_slot): New function.
-	(symbol_cache_mark_found, symbol_cache_mark_not_found): New functions.
-	(symbol_cache_flush, symbol_cache_dump): New functions.
-	(maintenance_print_symbol_cache): New function.
-	(maintenance_flush_symbol_cache): New function.
-	(symbol_cache_stats): New function.
-	(maintenance_print_symbol_cache_statistics): New function.
-	(symtab_new_objfile_observer): New function.
-	(symtab_free_objfile_observer): New function.
-	(lookup_static_symbol, lookup_global_symbol): Use symbol cache.
-	(_initialize_symtab): Init symbol_cache_key.  New parameter
-	maint symbol-cache-size.  New maint commands print symbol-cache,
-	print symbol-cache-statistics, flush-symbol-cache.
-	Install new_objfile, free_objfile observers.
-
 2015-01-09  Patrick Palka  <patrick@parcs.ath.cx>
 
 	* Makefile.in (.y.c): Don't munge yacc's #line
diff --git a/gdb/NEWS b/gdb/NEWS
index d21312a..f476970 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -63,15 +63,6 @@ add-auto-load-scripts-directory directory
 maint print user-registers
   List all currently available "user" registers.
 
-maint print symbol-cache
-  Print the contents of the symbol cache.
-
-maint print symbol-cache-statistics
-  Print statistics of symbol cache usage.
-
-maint flush-symbol-cache
-  Flush the contents of the symbol cache.
-
 compile code [-r|-raw] [--] [source code]
   Compile, inject, and execute in the inferior the executable object
   code produced by compiling the provided source code.
@@ -105,10 +96,6 @@ set debug symbol-lookup
 show debug symbol-lookup
   Control display of debugging info regarding symbol lookup.
 
-maint set symbol-cache-size
-maint show symbol-cache-size
-  Control the size of the symbol cache.
-
 * MI changes
 
   ** The -list-thread-groups command outputs an exit-code field for
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index e81a85b..33f233d 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -5,13 +5,6 @@
 	(Symbols): Ditto.
 	(Maintenance Commands): Delete docs for "maint demangle".
 
-2015-01-10  Doug Evans  <xdje42@gmail.com>
-
-	* gdb.texinfo (Symbols): Document new commands
-	"maint print symbol-cache", "maint print symbol-cache-statistics",
-	"maint flush-symbol-cache".  Document new option
-	"maint set symbol-cache-size".
-
 2014-12-31  Joel Brobecker  <brobecker@adacore.com>
 
 	* gdb.texinfo (Files): Remove documentation of the
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index bd8596c..b059ac2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -16489,40 +16489,9 @@ line 1574.
 @}
 (@value{GDBP})
 @end smallexample
-
-@kindex maint set symbol-cache-size
-@cindex symbol cache size
-@item maint set symbol-cache-size @var{size}
-Set the size of the symbol cache to @var{size}.
-The default size is intended to be good enough for debugging
-most applications.  This option exists to allow for experimenting
-with different sizes.
-
-@kindex maint show symbol-cache-size
-@item maint show symbol-cache-size
-Show the size of the symbol cache.
-
-@kindex maint print symbol-cache
-@cindex symbol cache, printing its contents
-@item maint print symbol-cache
-Print the contents of the symbol cache.
-This is useful when debugging symbol cache issues.
-
-@kindex maint print symbol-cache-statistics
-@cindex symbol cache, printing usage statistics
-@item maint print symbol-cache-statistics
-Print symbol cache usage statistics.
-This helps determine how well the cache is being utilized.
-
-@kindex maint flush-symbol-cache
-@cindex symbol cache, flushing
-@item maint flush-symbol-cache
-Flush the contents of the symbol cache, all entries are removed.
-This command is useful when debugging the symbol cache.
-It is also useful when collecting performance data.
-
 @end table
 
+
 @node Altering
 @chapter Altering Execution
 
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 321241b..b5d8d63 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -102,115 +102,12 @@ struct main_info
   enum language language_of_main;
 };
 
-/* Program space key for finding its symbol cache.  */
-
-static const struct program_space_data *symbol_cache_key;
-
-/* The default symbol cache size.
-   There is no extra cpu cost for large N (except when flushing the cache,
-   which is rare).  The value here is just a first attempt.  A better default
-   value may be higher or lower.  A prime number can make up for a bad hash
-   computation, so that's why the number is what it is.  */
-#define DEFAULT_SYMBOL_CACHE_SIZE 1021
-
-/* The maximum symbol cache size.
-   There's no method to the decision of what value to use here, other than
-   there's no point in allowing a user typo to make gdb consume all memory.  */
-#define MAX_SYMBOL_CACHE_SIZE (1024*1024)
-
-/* symbol_cache_lookup returns this if a previous lookup failed to find the
-   symbol in any objfile.  */
-#define SYMBOL_LOOKUP_FAILED ((struct symbol *) 1)
-
-/* Recording lookups that don't find the symbol is just as important, if not
-   more so, than recording found symbols.  */
-
-enum symbol_cache_slot_state
-{
-  SYMBOL_SLOT_UNUSED,
-  SYMBOL_SLOT_NOT_FOUND,
-  SYMBOL_SLOT_FOUND
-};
-
-/* Symbols don't specify global vs static block.
-   So keep them in separate caches.  */
-
-struct block_symbol_cache
-{
-  unsigned int hits;
-  unsigned int misses;
-  unsigned int collisions;
-
-  /* SYMBOLS is a variable length array of this size.
-     One can imagine that in general one cache (global/static) should be a
-     fraction of the size of the other, but there's no data at the moment
-     on which to decide.  */
-  unsigned int size;
-
-  struct symbol_cache_slot
-  {
-    enum symbol_cache_slot_state state;
-
-    /* The objfile that was current when the symbol was looked up.
-       This is only needed for global blocks, but for simplicity's sake
-       we allocate the space for both.  If data shows the extra space used
-       for static blocks is a problem, we can split things up then.
-
-       Global blocks need cache lookup to include the objfile context because
-       we need to account for gdbarch_iterate_over_objfiles_in_search_order
-       which can traverse objfiles in, effectively, any order, depending on
-       the current objfile, thus affecting which symbol is found.  Normally,
-       only the current objfile is searched first, and then the rest are
-       searched in recorded order; but putting cache lookup inside
-       gdbarch_iterate_over_objfiles_in_search_order would be awkward.
-       Instead we just make the current objfile part of the context of
-       cache lookup.  This means we can record the same symbol multiple times,
-       each with a different "current objfile" that was in effect when the
-       lookup was saved in the cache, but cache space is pretty cheap.  */
-    const struct objfile *objfile_context;
-
-    union
-    {
-      struct symbol *found;
-      struct
-      {
-	char *name;
-	domain_enum domain;
-      } not_found;
-    } value;
-  } symbols[1];
-};
-
-/* The symbol cache.
-
-   Searching for symbols in the static and global blocks over multiple objfiles
-   again and again can be slow, as can searching very big objfiles.  This is a
-   simple cache to improve symbol lookup performance, which is critical to
-   overall gdb performance.
-
-   Symbols are hashed on the name, its domain, and block.
-   They are also hashed on their objfile for objfile-specific lookups.  */
-
-struct symbol_cache
-{
-  struct block_symbol_cache *global_symbols;
-  struct block_symbol_cache *static_symbols;
-};
-
 /* When non-zero, print debugging messages related to symtab creation.  */
 unsigned int symtab_create_debug = 0;
 
 /* When non-zero, print debugging messages related to symbol lookup.  */
 unsigned int symbol_lookup_debug = 0;
 
-/* The size of the cache is staged here.  */
-static unsigned int new_symbol_cache_size = DEFAULT_SYMBOL_CACHE_SIZE;
-
-/* The current value of the symbol cache size.
-   This is saved so that if the user enters a value too big we can restore
-   the original value from here.  */
-static unsigned int symbol_cache_size = DEFAULT_SYMBOL_CACHE_SIZE;
-
 /* Non-zero if a file may be known by two different basenames.
    This is the uncommon case, and significantly slows down gdb.
    Default set to "off" to not slow down the common case.  */
@@ -1161,552 +1058,6 @@ expand_symtab_containing_pc (CORE_ADDR pc, struct obj_section *section)
   }
 }
 
-/* Hash function for the symbol cache.  */
-
-static unsigned int
-hash_symbol_entry (const struct objfile *objfile_context,
-		   const char *name, domain_enum domain)
-{
-  unsigned int hash = (uintptr_t) objfile_context;
-
-  if (name != NULL)
-    hash += htab_hash_string (name);
-
-  hash += domain;
-
-  return hash;
-}
-
-/* Equality function for the symbol cache.  */
-
-static int
-eq_symbol_entry (const struct symbol_cache_slot *slot,
-		 const struct objfile *objfile_context,
-		 const char *name, domain_enum domain)
-{
-  const char *slot_name;
-  domain_enum slot_domain;
-
-  if (slot->state == SYMBOL_SLOT_UNUSED)
-    return 0;
-
-  if (slot->objfile_context != objfile_context)
-    return 0;
-
-  if (slot->state == SYMBOL_SLOT_NOT_FOUND)
-    {
-      slot_name = slot->value.not_found.name;
-      slot_domain = slot->value.not_found.domain;
-    }
-  else
-    {
-      slot_name = SYMBOL_SEARCH_NAME (slot->value.found);
-      slot_domain = SYMBOL_DOMAIN (slot->value.found);
-    }
-
-  /* NULL names match.  */
-  if (slot_name == NULL && name == NULL)
-    {
-      /* But there's no point in calling symbol_matches_domain in the
-	 SYMBOL_SLOT_FOUND case.  */
-      if (slot_domain != domain)
-	return 0;
-    }
-  else if (slot_name != NULL && name != NULL)
-    {
-      /* It's important that we use the same comparison that was done the
-	 first time through.  If the slot records a found symbol, then this
-	 means using strcmp_iw on SYMBOL_SEARCH_NAME.  See dictionary.c.
-	 It also means using symbol_matches_domain for found symbols.
-	 See block.c.
-
-	 If the slot records a not-found symbol, then require a precise match.
-	 We could still be lax with whitespace like strcmp_iw though.  */
-
-      if (slot->state == SYMBOL_SLOT_NOT_FOUND)
-	{
-	  if (strcmp (slot_name, name) != 0)
-	    return 0;
-	  if (slot_domain != domain)
-	    return 0;
-	}
-      else
-	{
-	  struct symbol *sym = slot->value.found;
-
-	  if (strcmp_iw (slot_name, name) != 0)
-	    return 0;
-	  if (!symbol_matches_domain (SYMBOL_LANGUAGE (sym),
-				      slot_domain, domain))
-	    return 0;
-	}
-    }
-  else
-    {
-      /* Only one name is NULL.  */
-      return 0;
-    }
-
-  return 1;
-}
-
-/* Given a cache of size SIZE, return the size of the struct (with variable
-   length array) in bytes.  */
-
-static size_t
-symbol_cache_byte_size (unsigned int size)
-{
-  return (sizeof (struct block_symbol_cache)
-	  + ((size - 1) * sizeof (struct symbol_cache_slot)));
-}
-
-/* Resize CACHE.  */
-
-static void
-resize_symbol_cache (struct symbol_cache *cache, unsigned int new_size)
-{
-  /* If there's no change in size, don't do anything.
-     All caches have the same size, so we can just compare with the size
-     of the global symbols cache.  */
-  if ((cache->global_symbols != NULL
-       && cache->global_symbols->size == new_size)
-      || (cache->global_symbols == NULL
-	  && new_size == 0))
-    return;
-
-  xfree (cache->global_symbols);
-  xfree (cache->static_symbols);
-
-  if (new_size == 0)
-    {
-      cache->global_symbols = NULL;
-      cache->static_symbols = NULL;
-    }
-  else
-    {
-      size_t total_size = symbol_cache_byte_size (new_size);
-
-      cache->global_symbols = xcalloc (1, total_size);
-      cache->static_symbols = xcalloc (1, total_size);
-      cache->global_symbols->size = new_size;
-      cache->static_symbols->size = new_size;
-    }
-}
-
-/* Make a symbol cache of size SIZE.  */
-
-static struct symbol_cache *
-make_symbol_cache (unsigned int size)
-{
-  struct symbol_cache *cache;
-
-  cache = XCNEW (struct symbol_cache);
-  resize_symbol_cache (cache, symbol_cache_size);
-  return cache;
-}
-
-/* Free the space used by CACHE.  */
-
-static void
-free_symbol_cache (struct symbol_cache *cache)
-{
-  xfree (cache->global_symbols);
-  xfree (cache->static_symbols);
-  xfree (cache);
-}
-
-/* Return the symbol cache of PSPACE.
-   Create one if it doesn't exist yet.  */
-
-static struct symbol_cache *
-get_symbol_cache (struct program_space *pspace)
-{
-  struct symbol_cache *cache = program_space_data (pspace, symbol_cache_key);
-
-  if (cache == NULL)
-    {
-      cache = make_symbol_cache (symbol_cache_size);
-      set_program_space_data (pspace, symbol_cache_key, cache);
-    }
-
-  return cache;
-}
-
-/* Delete the symbol cache of PSPACE.
-   Called when PSPACE is destroyed.  */
-
-static void
-symbol_cache_cleanup (struct program_space *pspace, void *data)
-{
-  struct symbol_cache *cache = data;
-
-  free_symbol_cache (cache);
-}
-
-/* Set the size of the symbol cache in all program spaces.  */
-
-static void
-set_symbol_cache_size (unsigned int new_size)
-{
-  struct program_space *pspace;
-
-  ALL_PSPACES (pspace)
-    {
-      struct symbol_cache *cache
-	= program_space_data (pspace, symbol_cache_key);
-
-      /* The pspace could have been created but not have a cache yet.  */
-      if (cache != NULL)
-	resize_symbol_cache (cache, new_size);
-    }
-}
-
-/* Called when symbol-cache-size is set.  */
-
-static void
-set_symbol_cache_size_handler (char *args, int from_tty,
-			       struct cmd_list_element *c)
-{
-  if (new_symbol_cache_size > MAX_SYMBOL_CACHE_SIZE)
-    {
-      /* Restore the previous value.
-	 This is the value the "show" command prints.  */
-      new_symbol_cache_size = symbol_cache_size;
-
-      error (_("Symbol cache size is too large, max is %u."),
-	     MAX_SYMBOL_CACHE_SIZE);
-    }
-  symbol_cache_size = new_symbol_cache_size;
-
-  set_symbol_cache_size (symbol_cache_size);
-}
-
-/* Lookup symbol NAME,DOMAIN in BLOCK in the symbol cache of PSPACE.
-   OBJFILE_CONTEXT is the current objfile, which may be NULL.
-   The result is the symbol if found, SYMBOL_LOOKUP_FAILED if a previous lookup
-   failed (and thus this one will too), or NULL if the symbol is not present
-   in the cache.
-   *BSC_PTR, *SLOT_PTR are set to the cache and slot of the symbol, whether
-   found or not found.  */
-
-static struct symbol *
-symbol_cache_lookup (struct symbol_cache *cache,
-		     struct objfile *objfile_context, int block,
-		     const char *name, domain_enum domain,
-		     struct block_symbol_cache **bsc_ptr,
-		     struct symbol_cache_slot **slot_ptr)
-{
-  struct block_symbol_cache *bsc;
-  unsigned int hash;
-  struct symbol_cache_slot *slot;
-
-  if (block == GLOBAL_BLOCK)
-    bsc = cache->global_symbols;
-  else
-    bsc = cache->static_symbols;
-  if (bsc == NULL)
-    {
-      *bsc_ptr = NULL;
-      *slot_ptr = NULL;
-      return NULL;
-    }
-
-  hash = hash_symbol_entry (objfile_context, name, domain);
-  slot = bsc->symbols + hash % bsc->size;
-  *bsc_ptr = bsc;
-  *slot_ptr = slot;
-
-  if (eq_symbol_entry (slot, objfile_context, name, domain))
-    {
-      if (symbol_lookup_debug)
-	fprintf_unfiltered (gdb_stdlog,
-			    "%s block symbol cache hit%s for %s, %s\n",
-			    block == GLOBAL_BLOCK ? "Global" : "Static",
-			    slot->state == SYMBOL_SLOT_NOT_FOUND
-			    ? " (not found)" : "",
-			    name, domain_name (domain));
-      ++bsc->hits;
-      if (slot->state == SYMBOL_SLOT_NOT_FOUND)
-	return SYMBOL_LOOKUP_FAILED;
-      return slot->value.found;
-    }
-
-  if (symbol_lookup_debug)
-    {
-      fprintf_unfiltered (gdb_stdlog,
-			  "%s block symbol cache miss for %s, %s\n",
-			  block == GLOBAL_BLOCK ? "Global" : "Static",
-			  name, domain_name (domain));
-    }
-  ++bsc->misses;
-  return NULL;
-}
-
-/* Clear out SLOT.  */
-
-static void
-symbol_cache_clear_slot (struct symbol_cache_slot *slot)
-{
-  if (slot->state == SYMBOL_SLOT_NOT_FOUND)
-    xfree (slot->value.not_found.name);
-  slot->state = SYMBOL_SLOT_UNUSED;
-}
-
-/* Mark SYMBOL as found in SLOT.
-   OBJFILE_CONTEXT is the current objfile when the lookup was done, or NULL
-   if it's not needed to distinguish lookups (STATIC_BLOCK).  It is *not*
-   necessarily the objfile the symbol was found in.  */
-
-static void
-symbol_cache_mark_found (struct block_symbol_cache *bsc,
-			 struct symbol_cache_slot *slot,
-			 struct objfile *objfile_context,
-			 struct symbol *symbol)
-{
-  if (bsc == NULL)
-    return;
-  if (slot->state != SYMBOL_SLOT_UNUSED)
-    {
-      ++bsc->collisions;
-      symbol_cache_clear_slot (slot);
-    }
-  slot->state = SYMBOL_SLOT_FOUND;
-  slot->objfile_context = objfile_context;
-  slot->value.found = symbol;
-}
-
-/* Mark symbol NAME, DOMAIN as not found in SLOT.
-   OBJFILE_CONTEXT is the current objfile when the lookup was done, or NULL
-   if it's not needed to distinguish lookups (STATIC_BLOCK).  */
-
-static void
-symbol_cache_mark_not_found (struct block_symbol_cache *bsc,
-			     struct symbol_cache_slot *slot,
-			     struct objfile *objfile_context,
-			     const char *name, domain_enum domain)
-{
-  if (bsc == NULL)
-    return;
-  if (slot->state != SYMBOL_SLOT_UNUSED)
-    {
-      ++bsc->collisions;
-      symbol_cache_clear_slot (slot);
-    }
-  slot->state = SYMBOL_SLOT_NOT_FOUND;
-  slot->objfile_context = objfile_context;
-  slot->value.not_found.name = xstrdup (name);
-  slot->value.not_found.domain = domain;
-}
-
-/* Flush the symbol cache of PSPACE.  */
-
-static void
-symbol_cache_flush (struct program_space *pspace)
-{
-  struct symbol_cache *cache = program_space_data (pspace, symbol_cache_key);
-  int pass;
-  size_t total_size;
-
-  if (cache == NULL)
-    return;
-  if (cache->global_symbols == NULL)
-    {
-      gdb_assert (symbol_cache_size == 0);
-      gdb_assert (cache->static_symbols == NULL);
-      return;
-    }
-
-  /* If the cache is untouched since the last flush, early exit.
-     This is important for performance during the startup of a program linked
-     with 100s (or 1000s) of shared libraries.  */
-  if (cache->global_symbols->misses == 0
-      && cache->static_symbols->misses == 0)
-    return;
-
-  gdb_assert (cache->global_symbols->size == symbol_cache_size);
-  gdb_assert (cache->static_symbols->size == symbol_cache_size);
-
-  for (pass = 0; pass < 2; ++pass)
-    {
-      struct block_symbol_cache *bsc
-	= pass == 0 ? cache->global_symbols : cache->static_symbols;
-      unsigned int i;
-
-      for (i = 0; i < bsc->size; ++i)
-	symbol_cache_clear_slot (&bsc->symbols[i]);
-    }
-
-  cache->global_symbols->hits = 0;
-  cache->global_symbols->misses = 0;
-  cache->global_symbols->collisions = 0;
-  cache->static_symbols->hits = 0;
-  cache->static_symbols->misses = 0;
-  cache->static_symbols->collisions = 0;
-}
-
-/* Dump CACHE.  */
-
-static void
-symbol_cache_dump (const struct symbol_cache *cache)
-{
-  int pass;
-
-  if (cache->global_symbols == NULL)
-    {
-      printf_filtered ("  <disabled>\n");
-      return;
-    }
-
-  for (pass = 0; pass < 2; ++pass)
-    {
-      const struct block_symbol_cache *bsc
-	= pass == 0 ? cache->global_symbols : cache->static_symbols;
-      unsigned int i;
-
-      if (pass == 0)
-	printf_filtered ("Global symbols:\n");
-      else
-	printf_filtered ("Static symbols:\n");
-
-      for (i = 0; i < bsc->size; ++i)
-	{
-	  const struct symbol_cache_slot *slot = &bsc->symbols[i];
-
-	  QUIT;
-
-	  switch (slot->state)
-	    {
-	    case SYMBOL_SLOT_UNUSED:
-	      break;
-	    case SYMBOL_SLOT_NOT_FOUND:
-	      printf_filtered ("  [%-4u] = %s, %s (not found)\n", i,
-			       host_address_to_string (slot->objfile_context),
-			       slot->value.not_found.name);
-	      break;
-	    case SYMBOL_SLOT_FOUND:
-	      printf_filtered ("  [%-4u] = %s, %s\n", i,
-			       host_address_to_string (slot->objfile_context),
-			       SYMBOL_PRINT_NAME (slot->value.found));
-	      break;
-	    }
-	}
-    }
-}
-
-/* The "mt print symbol-cache" command.  */
-
-static void
-maintenance_print_symbol_cache (char *args, int from_tty)
-{
-  struct program_space *pspace;
-
-  ALL_PSPACES (pspace)
-    {
-      struct symbol_cache *cache;
-
-      printf_filtered (_("Symbol cache for pspace %d\n%s:\n"),
-		       pspace->num,
-		       pspace->symfile_object_file != NULL
-		       ? objfile_name (pspace->symfile_object_file)
-		       : "(no object file)");
-
-      /* If the cache hasn't been created yet, avoid creating one.  */
-      cache = program_space_data (pspace, symbol_cache_key);
-      if (cache == NULL)
-	printf_filtered ("  <empty>\n");
-      else
-	symbol_cache_dump (cache);
-    }
-}
-
-/* The "mt flush-symbol-cache" command.  */
-
-static void
-maintenance_flush_symbol_cache (char *args, int from_tty)
-{
-  struct program_space *pspace;
-
-  ALL_PSPACES (pspace)
-    {
-      symbol_cache_flush (pspace);
-    }
-}
-
-/* Print usage statistics of CACHE.  */
-
-static void
-symbol_cache_stats (struct symbol_cache *cache)
-{
-  int pass;
-
-  if (cache->global_symbols == NULL)
-    {
-      printf_filtered ("  <disabled>\n");
-      return;
-    }
-
-  for (pass = 0; pass < 2; ++pass)
-    {
-      const struct block_symbol_cache *bsc
-	= pass == 0 ? cache->global_symbols : cache->static_symbols;
-
-      QUIT;
-
-      if (pass == 0)
-	printf_filtered ("Global block cache stats:\n");
-      else
-	printf_filtered ("Static block cache stats:\n");
-
-      printf_filtered ("  size:       %u\n", bsc->size);
-      printf_filtered ("  hits:       %u\n", bsc->hits);
-      printf_filtered ("  misses:     %u\n", bsc->misses);
-      printf_filtered ("  collisions: %u\n", bsc->collisions);
-    }
-}
-
-/* The "mt print symbol-cache-statistics" command.  */
-
-static void
-maintenance_print_symbol_cache_statistics (char *args, int from_tty)
-{
-  struct program_space *pspace;
-
-  ALL_PSPACES (pspace)
-    {
-      struct symbol_cache *cache;
-
-      printf_filtered (_("Symbol cache statistics for pspace %d\n%s:\n"),
-		       pspace->num,
-		       pspace->symfile_object_file != NULL
-		       ? objfile_name (pspace->symfile_object_file)
-		       : "(no object file)");
-
-      /* If the cache hasn't been created yet, avoid creating one.  */
-      cache = program_space_data (pspace, symbol_cache_key);
-      if (cache == NULL)
- 	printf_filtered ("  empty, no stats available\n");
-      else
-	symbol_cache_stats (cache);
-    }
-}
-
-/* This module's 'new_objfile' observer.  */
-
-static void
-symtab_new_objfile_observer (struct objfile *objfile)
-{
-  /* Ideally we'd use OBJFILE->pspace, but OBJFILE may be NULL.  */
-  symbol_cache_flush (current_program_space);
-}
-
-/* This module's 'free_objfile' observer.  */
-
-static void
-symtab_free_objfile_observer (struct objfile *objfile)
-{
-  symbol_cache_flush (objfile->pspace);
-}
-
 /* Debug symbols usually don't have section information.  We need to dig that
    out of the minimal symbols and stash that in the debug symbol.  */
 
@@ -2619,36 +1970,16 @@ lookup_symbol_in_objfile (struct objfile *objfile, int block_index,
 struct symbol *
 lookup_static_symbol (const char *name, const domain_enum domain)
 {
-  struct symbol_cache *cache = get_symbol_cache (current_program_space);
   struct objfile *objfile;
   struct symbol *result;
-  struct block_symbol_cache *bsc;
-  struct symbol_cache_slot *slot;
-
-  /* Lookup in STATIC_BLOCK is not current-objfile-dependent, so just pass
-     NULL for OBJFILE_CONTEXT.  */
-  result = symbol_cache_lookup (cache, NULL, STATIC_BLOCK, name, domain,
-				&bsc, &slot);
-  if (result != NULL)
-    {
-      if (result == SYMBOL_LOOKUP_FAILED)
-	return NULL;
-      return result;
-    }
 
   ALL_OBJFILES (objfile)
     {
       result = lookup_symbol_in_objfile (objfile, STATIC_BLOCK, name, domain);
       if (result != NULL)
-	{
-	  /* Still pass NULL for OBJFILE_CONTEXT here.  */
-	  symbol_cache_mark_found (bsc, slot, NULL, result);
-	  return result;
-	}
+	return result;
     }
 
-  /* Still pass NULL for OBJFILE_CONTEXT here.  */
-  symbol_cache_mark_not_found (bsc, slot, NULL, name, domain);
   return NULL;
 }
 
@@ -2696,48 +2027,25 @@ lookup_global_symbol (const char *name,
 		      const struct block *block,
 		      const domain_enum domain)
 {
-  struct symbol_cache *cache = get_symbol_cache (current_program_space);
-  struct symbol *sym;
-  struct objfile *objfile;
+  struct symbol *sym = NULL;
+  struct objfile *objfile = NULL;
   struct global_sym_lookup_data lookup_data;
-  struct block_symbol_cache *bsc;
-  struct symbol_cache_slot *slot;
-
-  objfile = lookup_objfile_from_block (block);
-
-  /* First see if we can find the symbol in the cache.
-     This works because we use the current objfile to qualify the lookup.  */
-  sym = symbol_cache_lookup (cache, objfile, GLOBAL_BLOCK, name, domain,
-			     &bsc, &slot);
-  if (sym != NULL)
-    {
-      if (sym == SYMBOL_LOOKUP_FAILED)
-	return NULL;
-      return sym;
-    }
 
   /* Call library-specific lookup procedure.  */
+  objfile = lookup_objfile_from_block (block);
   if (objfile != NULL)
     sym = solib_global_lookup (objfile, name, domain);
-
-  /* If that didn't work go a global search (of global blocks, heh).  */
-  if (sym == NULL)
-    {
-      memset (&lookup_data, 0, sizeof (lookup_data));
-      lookup_data.name = name;
-      lookup_data.domain = domain;
-      gdbarch_iterate_over_objfiles_in_search_order
-	(objfile != NULL ? get_objfile_arch (objfile) : target_gdbarch (),
-	 lookup_symbol_global_iterator_cb, &lookup_data, objfile);
-      sym = lookup_data.result;
-    }
-
   if (sym != NULL)
-    symbol_cache_mark_found (bsc, slot, objfile, sym);
-  else
-    symbol_cache_mark_not_found (bsc, slot, objfile, name, domain);
+    return sym;
 
-  return sym;
+  memset (&lookup_data, 0, sizeof (lookup_data));
+  lookup_data.name = name;
+  lookup_data.domain = domain;
+  gdbarch_iterate_over_objfiles_in_search_order
+    (objfile != NULL ? get_objfile_arch (objfile) : target_gdbarch (),
+     lookup_symbol_global_iterator_cb, &lookup_data, objfile);
+
+  return lookup_data.result;
 }
 
 int
@@ -6128,9 +5436,6 @@ _initialize_symtab (void)
   main_progspace_key
     = register_program_space_data_with_cleanup (NULL, main_info_cleanup);
 
-  symbol_cache_key
-    = register_program_space_data_with_cleanup (NULL, symbol_cache_cleanup);
-
   add_info ("variables", variables_info, _("\
 All global and static variable names, or those matching REGEXP."));
   if (dbx_commands)
@@ -6206,31 +5511,5 @@ When enabled (non-zero), symbol lookups are logged."),
 			   NULL, NULL,
 			   &setdebuglist, &showdebuglist);
 
-  add_setshow_zuinteger_cmd ("symbol-cache-size", no_class,
-			     &new_symbol_cache_size,
-			     _("Set the size of the symbol cache."),
-			     _("Show the size of the symbol cache."), _("\
-The size of the symbol cache.\n\
-If zero then the symbol cache is disabled."),
-			     set_symbol_cache_size_handler, NULL,
-			     &maintenance_set_cmdlist,
-			     &maintenance_show_cmdlist);
-
-  add_cmd ("symbol-cache", class_maintenance, maintenance_print_symbol_cache,
-	   _("Dump the symbol cache for each program space."),
-	   &maintenanceprintlist);
-
-  add_cmd ("symbol-cache-statistics", class_maintenance,
-	   maintenance_print_symbol_cache_statistics,
-	   _("Print symbol cache statistics for each program space."),
-	   &maintenanceprintlist);
-
-  add_cmd ("flush-symbol-cache", class_maintenance,
-	   maintenance_flush_symbol_cache,
-	   _("Flush the symbol cache for each program space."),
-	   &maintenancelist);
-
   observer_attach_executable_changed (symtab_observer_executable_changed);
-  observer_attach_new_objfile (symtab_new_objfile_observer);
-  observer_attach_free_objfile (symtab_free_objfile_observer);
 }