Re: PATCH: PR ld/3191: Linker failed to handle DW_FORM_ref_addr properly

["H. J. Lu" <hjl at lucon dot org>]

On Wed, Sep 20, 2006 at 05:54:11PM -0700, H. J. Lu wrote:
> On Wed, Sep 20, 2006 at 03:19:22PM -0700, H. J. Lu wrote:
> > On Tue, Sep 19, 2006 at 10:20:10PM -0700, H. J. Lu wrote:
> > > On Tue, Sep 19, 2006 at 09:37:02PM -0700, H. J. Lu wrote:
> > > > DW_FORM_ref_addr is offset_size according to DWARF3 and gcc follows
> > > > DWARF3. This patch fixes
> > > > 
> > > > http://sourceware.org/bugzilla/show_bug.cgi?id=3191
> > > > 
> > > > 
> > 
> > It turns out that the problem is we didn't properly adjust debug_info
> > section vmas when we put them together. I think this is a right fix.
> > 
> > 
> 
> Here is the updated patch. Can we assume debug section vma is 0 and
> we don't need to reset it after adjustment and relocation?
> 
> 

We do need to reset section vma to 0 since it may be just a warning and
we may generate an executable.

H.J.
---
2006-09-21  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/3191
	* dwarf2.c (_bfd_dwarf2_find_nearest_line): Adjust debug_info
	section vma when needed.

--- bfd/dwarf2.c.ref_addr	2006-09-16 19:44:38.000000000 -0700
+++ bfd/dwarf2.c	2006-09-21 08:01:13.000000000 -0700
@@ -2375,6 +2375,11 @@ _bfd_dwarf2_find_nearest_line (bfd *abfd
     {
       bfd_size_type total_size;
       asection *msec;
+      bfd_vma last_vma;
+      bfd_size_type size;
+      asection *first_msec;
+      asection **msecs = NULL;
+      unsigned int i, count;
 
       *pinfo = stash;
 
@@ -2389,9 +2394,28 @@ _bfd_dwarf2_find_nearest_line (bfd *abfd
 	 Read them all in and produce one large stash.  We do this in two
 	 passes - in the first pass we just accumulate the section sizes.
 	 In the second pass we read in the section's contents.  The allows
-	 us to avoid reallocing the data as we add sections to the stash.  */
+	 us to avoid reallocing the data as we add sections to the stash.
+       
+	 We may need to adjust debug_info section vmas since we will
+	 concatenate them together.  Otherwise relocations may be
+	 incorrect.  */
+      first_msec = msec;
+      last_vma = 0;
+      count = 0;
       for (total_size = 0; msec; msec = find_debug_info (abfd, msec))
-	total_size += msec->size;
+	{
+	  size = msec->size;
+	  if (size == 0)
+	    continue;
+
+	  total_size += size;
+
+	  BFD_ASSERT (msec->vma == 0 && msec->alignment_power == 0);
+
+	  msec->vma = last_vma;
+	  last_vma += size;
+	  count++;
+	}
 
       stash->info_ptr = bfd_alloc (abfd, total_size);
       if (stash->info_ptr == NULL)
@@ -2399,17 +2423,27 @@ _bfd_dwarf2_find_nearest_line (bfd *abfd
 
       stash->info_ptr_end = stash->info_ptr;
 
-      for (msec = find_debug_info (abfd, NULL);
+      if (count > 1)
+	{
+	  count--;
+	  msecs = (asection **) bfd_malloc2 (count, sizeof (*msecs));
+	}
+
+      for (i = 0, msec = first_msec;
 	   msec;
 	   msec = find_debug_info (abfd, msec))
 	{
-	  bfd_size_type size;
 	  bfd_size_type start;
 
 	  size = msec->size;
 	  if (size == 0)
 	    continue;
 
+	  if (i && msecs)
+	    msecs [i - 1] = msec;
+
+	  i++;
+
 	  start = stash->info_ptr_end - stash->info_ptr;
 
 	  if ((bfd_simple_get_relocated_section_contents
@@ -2419,9 +2453,27 @@ _bfd_dwarf2_find_nearest_line (bfd *abfd
 	  stash->info_ptr_end = stash->info_ptr + start + size;
 	}
 
+      /* Restore section vma. */
+      if (count)
+	{
+	  if (msecs)
+	    {
+	      for (i = 0; i < count; i++)
+		msecs [i]->vma = 0;
+	      free (msecs);
+	    }
+	  else
+	    {
+	      for (msec = find_debug_info (abfd, first_msec);
+		   msec;
+		   msec = find_debug_info (abfd, msec))
+		msec->vma = 0;
+	    }
+	}
+
       BFD_ASSERT (stash->info_ptr_end == stash->info_ptr + total_size);
 
-      stash->sec = find_debug_info (abfd, NULL);
+      stash->sec = first_msec;
       stash->sec_info_ptr = stash->info_ptr;
       stash->syms = symbols;
     }