Re: FYI: minor simplification in add_psymbol_to_bcache

[Tom Tromey <tromey@redhat.com>]

>>>>> "Daniel" == Daniel Jacobowitz <drow@false.org> writes:

>> On Wed, Nov 04, 2009 at 12:16:27PM -0700, Tom Tromey wrote:
>> TBH I was not thinking too soundly, I suppose, when I nuked this.  I
>> think your point is a good one.  If you'd prefer, I will leave this
>> static and just zero out that field.

Daniel> Unless you have a good reason not to, I suggest making that change.

Here is the patch I am checking in.

Tom

2009-11-05  Tom Tromey  <tromey@redhat.com>

	* symfile.c (add_psymbol_to_bcache): Make 'psymbol' static again.
	Zero the 'value' field.

Index: symfile.c
===================================================================
RCS file: /cvs/src/src/gdb/symfile.c,v
retrieving revision 1.253
diff -u -r1.253 symfile.c
--- symfile.c	5 Nov 2009 19:53:04 -0000	1.253
+++ symfile.c	5 Nov 2009 22:15:30 -0000
@@ -3105,9 +3105,15 @@
 		       enum language language, struct objfile *objfile,
 		       int *added)
 {
-  struct partial_symbol psymbol;
-
-  memset (&psymbol, 0, sizeof (struct partial_symbol));
+  /* psymbol is static so that there will be no uninitialized gaps in the
+     structure which might contain random data, causing cache misses in
+     bcache. */
+  static struct partial_symbol psymbol;
+
+  /* However, we must ensure that the entire 'value' field has been
+     zeroed before assigning to it, because an assignment may not
+     write the entire field.  */
+  memset (&psymbol.ginfo.value, 0, sizeof (psymbol.ginfo.value));
   /* val and coreaddr are mutually exclusive, one of them *will* be zero */
   if (val != 0)
     {