[PATCH 20/20] Introduce and use bcache_up

[Tom Tromey <tom at tromey dot com>]

This introduces a new bcache_up typedef, which is a unique_ptr
specialization for managing a bcache.  Then, this changes various
spots to use this object, rather than manually calling bcache_xfree.
This lets us remove a try/catch that only existed to call
bcache_xfree.

gdb/ChangeLog
2019-02-13  Tom Tromey  <tom@tromey.com>

	* symmisc.c (print_symbol_bcache_statistics)
	(print_objfile_statistics): Update.
	* symfile.c (allocate_symtab): Update.
	* psymtab.c (allocate_psymtab): Update.
	* objfiles.h (struct objfile_per_bfd_storage) <filename_cache,
	macro_cache>: Change type to bcache_up.
	* objfiles.c (get_objfile_bfd_data): Update.
	(free_objfile_per_bfd_storage): Don't call bcache_xfree.
	* gdbtypes.c (types_deeply_equal): Use bcache_up.
	* elfread.c (elf_symtab_read): Update.
	* buildsym.c (buildsym_compunit::get_macro_table): Update.
	* bcache.h (struct bcache_deleter): New.
	(bcache_up): New typedef.
---
 gdb/ChangeLog  | 16 ++++++++++++++++
 gdb/bcache.h   | 12 ++++++++++++
 gdb/buildsym.c |  2 +-
 gdb/elfread.c  |  2 +-
 gdb/gdbtypes.c | 26 ++------------------------
 gdb/objfiles.c |  6 ++----
 gdb/objfiles.h |  6 +++---
 gdb/psymtab.c  |  2 +-
 gdb/symfile.c  |  2 +-
 gdb/symmisc.c  |  8 ++++----
 10 files changed, 43 insertions(+), 39 deletions(-)

diff --git a/gdb/bcache.h b/gdb/bcache.h
index aa0147926c6..9c1f71b6018 100644
--- a/gdb/bcache.h
+++ b/gdb/bcache.h
@@ -156,6 +156,18 @@ extern const void *bcache_full (const void *addr, int length,
 /* Free all the storage used by BCACHE.  */
 extern void bcache_xfree (struct bcache *bcache);
 
+/* A deleter that calls bcache_xfree.  */
+struct bcache_deleter
+{
+  void operator() (struct bcache *bcache)
+  {
+    bcache_xfree (bcache);
+  }
+};
+
+/* A unique pointer specialization for bcache.  */
+typedef std::unique_ptr<struct bcache, bcache_deleter> bcache_up;
+
 /* Create a new bcache object.  */
 extern struct bcache *bcache_xmalloc (
     unsigned long (*hash_function)(const void *, int length),
diff --git a/gdb/buildsym.c b/gdb/buildsym.c
index bd0f25e061e..2b70d43e3a0 100644
--- a/gdb/buildsym.c
+++ b/gdb/buildsym.c
@@ -122,7 +122,7 @@ buildsym_compunit::get_macro_table ()
 {
   if (m_pending_macros == nullptr)
     m_pending_macros = new_macro_table (&m_objfile->per_bfd->storage_obstack,
-					m_objfile->per_bfd->macro_cache,
+					m_objfile->per_bfd->macro_cache.get (),
 					m_compunit_symtab);
   return m_pending_macros;
 }
diff --git a/gdb/elfread.c b/gdb/elfread.c
index 8fc6692b112..2f274692348 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -335,7 +335,7 @@ elf_symtab_read (minimal_symbol_reader &reader,
 	{
 	  filesymname
 	    = (const char *) bcache (sym->name, strlen (sym->name) + 1,
-				     objfile->per_bfd->filename_cache);
+				     objfile->per_bfd->filename_cache.get ());
 	}
       else if (sym->flags & BSF_SECTION_SYM)
 	continue;
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index a473da1cad6..9e32c22c74f 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -3745,9 +3745,6 @@ check_types_worklist (std::vector<type_equality_entry> *worklist,
 bool
 types_deeply_equal (struct type *type1, struct type *type2)
 {
-  struct gdb_exception except = exception_none;
-  bool result = false;
-  struct bcache *cache;
   std::vector<type_equality_entry> worklist;
 
   gdb_assert (type1 != NULL && type2 != NULL);
@@ -3756,30 +3753,11 @@ types_deeply_equal (struct type *type1, struct type *type2)
   if (type1 == type2)
     return true;
 
-  cache = bcache_xmalloc (NULL, NULL);
+  bcache_up cache (bcache_xmalloc (NULL, NULL));
 
   worklist.emplace_back (type1, type2);
 
-  /* check_types_worklist calls several nested helper functions, some
-     of which can raise a GDB exception, so we just check and rethrow
-     here.  If there is a GDB exception, a comparison is not capable
-     (or trusted), so exit.  */
-  try
-    {
-      result = check_types_worklist (&worklist, cache);
-    }
-  catch (struct gdb_exception_RETURN_MASK_ALL &ex)
-    {
-      except = ex;
-    }
-
-  bcache_xfree (cache);
-
-  /* Rethrow if there was a problem.  */
-  if (except.reason < 0)
-    throw_exception (except);
-
-  return result;
+  return check_types_worklist (&worklist, cache.get ());
 }
 
 /* Allocated status of type TYPE.  Return zero if type TYPE is allocated.
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 34b271e86de..47bb5a83538 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -157,8 +157,8 @@ get_objfile_bfd_data (struct objfile *objfile, struct bfd *abfd)
       if (abfd != NULL)
 	storage->gdbarch = gdbarch_from_bfd (abfd);
 
-      storage->filename_cache = bcache_xmalloc (NULL, NULL);
-      storage->macro_cache = bcache_xmalloc (NULL, NULL);
+      storage->filename_cache.reset (bcache_xmalloc (NULL, NULL));
+      storage->macro_cache.reset (bcache_xmalloc (NULL, NULL));
       storage->language_of_main = language_unknown;
     }
 
@@ -170,8 +170,6 @@ get_objfile_bfd_data (struct objfile *objfile, struct bfd *abfd)
 static void
 free_objfile_per_bfd_storage (struct objfile_per_bfd_storage *storage)
 {
-  bcache_xfree (storage->filename_cache);
-  bcache_xfree (storage->macro_cache);
   if (storage->demangled_names_hash)
     htab_delete (storage->demangled_names_hash);
   storage->~objfile_per_bfd_storage ();
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index a10781f598e..272fd6a6204 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -31,8 +31,8 @@
 #include <vector>
 #include "common/next-iterator.h"
 #include "common/safe-iterator.h"
+#include "bcache.h"
 
-struct bcache;
 struct htab;
 struct objfile_data;
 struct partial_symbol;
@@ -240,11 +240,11 @@ struct objfile_per_bfd_storage
 
   /* Byte cache for file names.  */
 
-  struct bcache *filename_cache = NULL;
+  bcache_up filename_cache;
 
   /* Byte cache for macros.  */
 
-  struct bcache *macro_cache = NULL;
+  bcache_up macro_cache;
 
   /* The gdbarch associated with the BFD.  Note that this gdbarch is
      determined solely from BFD information, without looking at target
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index 17db29759c4..d6a5db47188 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -1742,7 +1742,7 @@ allocate_psymtab (const char *filename, struct objfile *objfile)
 
   psymtab->filename
     = (const char *) bcache (filename, strlen (filename) + 1,
-			     objfile->per_bfd->filename_cache);
+			     objfile->per_bfd->filename_cache.get ());
   psymtab->compunit_symtab = NULL;
 
   if (symtab_create_debug)
diff --git a/gdb/symfile.c b/gdb/symfile.c
index 61483824f63..7ea060c437c 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -2796,7 +2796,7 @@ allocate_symtab (struct compunit_symtab *cust, const char *filename)
 
   symtab->filename
     = (const char *) bcache (filename, strlen (filename) + 1,
-			     objfile->per_bfd->filename_cache);
+			     objfile->per_bfd->filename_cache.get ());
   symtab->fullname = NULL;
   symtab->language = deduce_language_from_filename (filename);
 
diff --git a/gdb/symmisc.c b/gdb/symmisc.c
index f7eae7e5f9b..082f10028f5 100644
--- a/gdb/symmisc.c
+++ b/gdb/symmisc.c
@@ -72,9 +72,9 @@ print_symbol_bcache_statistics (void)
 	print_bcache_statistics
 	  (psymbol_bcache_get_bcache (objfile->partial_symtabs->psymbol_cache),
 	   "partial symbol cache");
-	print_bcache_statistics (objfile->per_bfd->macro_cache,
+	print_bcache_statistics (objfile->per_bfd->macro_cache.get (),
 				 "preprocessor macro cache");
-	print_bcache_statistics (objfile->per_bfd->filename_cache,
+	print_bcache_statistics (objfile->per_bfd->filename_cache.get (),
 				 "file name cache");
       }
 }
@@ -139,9 +139,9 @@ print_objfile_statistics (void)
 	 bcache_memory_used (psymbol_bcache_get_bcache
 			     (objfile->partial_symtabs->psymbol_cache)));
       printf_filtered (_("  Total memory used for macro cache: %d\n"),
-		       bcache_memory_used (objfile->per_bfd->macro_cache));
+		       bcache_memory_used (objfile->per_bfd->macro_cache.get ()));
       printf_filtered (_("  Total memory used for file name cache: %d\n"),
-		       bcache_memory_used (objfile->per_bfd->filename_cache));
+		       bcache_memory_used (objfile->per_bfd->filename_cache.get ()));
     }
 }
 
-- 
2.17.2