Re: [patch] Fix for PR gdb/10819

[Paul Pluzhnikov <ppluzhnikov@google.com>]

[-- Attachment #1: Type: text/plain, Size: 705 bytes --]

On Thu, Oct 22, 2009 at 10:43 AM, Tom Tromey <tromey@redhat.com> wrote:

> Paul> +  /* See comment in dwarf2-frame.c:find_cie on why this check
> Paul> +     is necessary.  */
>
> I'm not ok with this comment; references like this are fragile because
> the referenced comment may change without anybody knowing to update this
> one.

How about this one then?
Tested on Linux/x86_64, no regressions.

Thanks,
-- 
Paul Pluzhnikov

2009-10-22  Paul Pluzhnikov  <ppluzhnikov@google.com>

     PR gdb/10819
     * dwarf2-frame.c (find_cie): Don't call bsearch on
     empty cie_table.
     * objfiles.c (find_pc_section): Likewise.
     (update_section_map): Don't allocate empty table.

[-- Attachment #2: gdb-pr10819-20091022-3.txt --]
[-- Type: text/plain, Size: 1877 bytes --]

Index: dwarf2-frame.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2-frame.c,v
retrieving revision 1.100
diff -u -p -u -r1.100 dwarf2-frame.c
--- dwarf2-frame.c	6 Oct 2009 23:27:04 -0000	1.100
+++ dwarf2-frame.c	22 Oct 2009 18:26:31 -0000
@@ -1525,6 +1525,14 @@ find_cie (struct dwarf2_cie_table *cie_t
 {
   struct dwarf2_cie **p_cie;
 
+  /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
+     bsearch be non-NULL.  */
+  if (cie_table->entries == NULL)
+    {
+      gdb_assert (cie_table->num_entries == 0);
+      return NULL;
+    }
+
   p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
                    sizeof (cie_table->entries[0]), bsearch_cie_cmp);
   if (p_cie != NULL)
Index: objfiles.c
===================================================================
RCS file: /cvs/src/src/gdb/objfiles.c,v
retrieving revision 1.99
diff -u -p -u -r1.99 objfiles.c
--- objfiles.c	19 Oct 2009 09:51:41 -0000	1.99
+++ objfiles.c	22 Oct 2009 18:26:31 -0000
@@ -1113,6 +1113,14 @@ update_section_map (struct program_space
       if (insert_section_p (objfile->obfd, s->the_bfd_section))
 	alloc_size += 1;
 
+  /* This happens on detach/attach (e.g. in gdb.base/attach.exp).  */
+  if (alloc_size == 0)
+    {
+      *pmap = NULL;
+      *pmap_size = 0;
+      return;
+    }
+
   map = xmalloc (alloc_size * sizeof (*map));
 
   i = 0;
@@ -1175,6 +1183,14 @@ find_pc_section (CORE_ADDR pc)
       pspace_info->objfiles_changed_p = 0;
     }
 
+  /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
+     bsearch be non-NULL.  */
+  if (pspace_info->sections == NULL)
+    {
+      gdb_assert (pspace_info->num_sections == 0);
+      return NULL;
+    }
+
   sp = (struct obj_section **) bsearch (&pc,
 					pspace_info->sections,
 					pspace_info->num_sections,