Re: [patch] Speed up find_pc_section

[Paul Pluzhnikov <ppluzhnikov@google.com>]

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On Fri, Aug 21, 2009 at 4:30 AM, Ulrich Weigand <uweigand@de.ibm.com> wrote:

> (A cleaner fix might be to fix all callers to never pass in a NULL
> section argument --most already don't-- and simply rely on it.)

Attached patch does that ...
Not tested (I still haven't figured out how to test overlays).

> I'm still not completely happy about the assertions you added.  An
> assertion failure is supposed to be an indication of a bug in GDB
> -- it should never be possible to trigger the assertion just by
> providing particular user input (this includes the binary file).

I am still working on fixing that part...

Thanks,
--
Paul Pluzhnikov

2009-08-23  Paul Pluzhnikov  <ppluzhnikov@google.com>

        * minsyms.c (lookup_minimal_symbol_by_pc_section_1): Assume
non-NULL section.
        (lookup_minimal_symbol_by_pc_section): Check for NULL section.
        (lookup_minimal_symbol_by_pc): Adjust.

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Index: minsyms.c
===================================================================
RCS file: /cvs/src/src/gdb/minsyms.c,v
retrieving revision 1.66
diff -u -p -u -r1.66 minsyms.c
--- minsyms.c	28 Jun 2009 00:20:22 -0000	1.66
+++ minsyms.c	22 Aug 2009 18:01:37 -0000
@@ -457,18 +457,10 @@ lookup_minimal_symbol_by_pc_section_1 (C
   struct objfile *objfile;
   struct minimal_symbol *msymbol;
   struct minimal_symbol *best_symbol = NULL;
-  struct obj_section *pc_section;
   enum minimal_symbol_type want_type, other_type;
 
   want_type = want_trampoline ? mst_solib_trampoline : mst_text;
   other_type = want_trampoline ? mst_text : mst_solib_trampoline;
-  
-  /* PC has to be in a known section.  This ensures that anything
-     beyond the end of the last segment doesn't appear to be part of
-     the last function in the last segment.  */
-  pc_section = find_pc_section (pc);
-  if (pc_section == NULL)
-    return NULL;
 
   /* We can not require the symbol found to be in pc_section, because
      e.g. IRIX 6.5 mdebug relies on this code returning an absolute
@@ -479,7 +471,7 @@ lookup_minimal_symbol_by_pc_section_1 (C
      files, search both the file and its separate debug file.  There's
      no telling which one will have the minimal symbols.  */
 
-  objfile = pc_section->objfile;
+  objfile = section->objfile;
   if (objfile->separate_debug_objfile)
     objfile = objfile->separate_debug_objfile;
 
@@ -680,6 +672,12 @@ lookup_minimal_symbol_by_pc_section_1 (C
 struct minimal_symbol *
 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
 {
+  if (section == NULL)
+    {
+      section = find_pc_section (pc);
+      if (section == NULL)
+	return NULL;
+    }
   return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
 }
 
@@ -695,7 +693,7 @@ lookup_minimal_symbol_by_pc (CORE_ADDR p
   struct obj_section *section = find_pc_section (pc);
   if (section == NULL)
     return NULL;
-  return lookup_minimal_symbol_by_pc_section (pc, section);
+  return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
 }
 \f