[PATCH] Debug information checking

[Andrew Stubbs <ams at codesourcery dot com>]

Hi all,

I'm investigating a problem in which I see the following message:

> arm-none-eabi-ld: Dwarf Error: Offset (273) greater than or equal to .debug_str size (268).

Unfortunately, I haven't figured out what's causing the problem, but I 
have discovered that the linker only detects this condition some of the 
time - specifically when it is the first read from the .debug_str 
section. The rest of the time it just reads from the offset even though 
it's out of range.

Note that you only get to this code when there are undefined symbols and 
the link is about to fail - it's looking for the filename and line number.

The attached patch ensures that it never misses a broken offset.

Does anybody have any clues what could be causing the real problem - the 
apparently broken debug info? The size given for .debug_str is 
incorrect, but I don't yet know why.

Anyway, is this patch OK?

Andrew
2009-03-11  Andrew Stubbs  <ams@codesourcery.com>

	bfd/
	* dwarf2.c (read_section): Always check the offset, even when the
	section has been read before.

---
 src/binutils-mainline/bfd/dwarf2.c |   76 ++++++++++++++++++++--------------------
 1 files changed, 38 insertions(+), 38 deletions(-)

Index: src/binutils-mainline/bfd/dwarf2.c
===================================================================
--- src/binutils-mainline/bfd/dwarf2.c.orig
+++ src/binutils-mainline/bfd/dwarf2.c
@@ -417,49 +417,49 @@ read_section (bfd *           abfd,
   bfd_boolean section_is_compressed = FALSE;
 
   /* read_section is a noop if the section has already been read.  */
-  if (*section_buffer)
-    return TRUE;
-
-  msec = bfd_get_section_by_name (abfd, section_name);
-  if (! msec && compressed_section_name)
-    {
-      msec = bfd_get_section_by_name (abfd, compressed_section_name);
-      section_is_compressed = TRUE;
-    }
-  if (! msec)
-    {
-      (*_bfd_error_handler) (_("Dwarf Error: Can't find %s section."), section_name);
-      bfd_set_error (bfd_error_bad_value);
-      return FALSE;
-    }
-
-  if (syms)
+  if (!*section_buffer)
     {
-      *section_size = msec->size;
-      *section_buffer
-	  = bfd_simple_get_relocated_section_contents (abfd, msec, NULL, syms);
-      if (! *section_buffer)
-	return FALSE;
-    }
-  else
-    {
-      *section_size = msec->rawsize ? msec->rawsize : msec->size;
-      *section_buffer = bfd_malloc (*section_size);
-      if (! *section_buffer)
-	return FALSE;
-      if (! bfd_get_section_contents (abfd, msec, *section_buffer,
-				      0, *section_size))
-	return FALSE;
-    }
-
-  if (section_is_compressed)
-    {
-      if (! bfd_uncompress_section_contents (section_buffer, section_size))
+      msec = bfd_get_section_by_name (abfd, section_name);
+      if (! msec && compressed_section_name)
 	{
-	  (*_bfd_error_handler) (_("Dwarf Error: unable to decompress %s section."), compressed_section_name);
+	  msec = bfd_get_section_by_name (abfd, compressed_section_name);
+	  section_is_compressed = TRUE;
+	}
+      if (! msec)
+	{
+	  (*_bfd_error_handler) (_("Dwarf Error: Can't find %s section."), section_name);
 	  bfd_set_error (bfd_error_bad_value);
 	  return FALSE;
 	}
+
+      if (syms)
+	{
+	  *section_size = msec->size;
+	  *section_buffer
+	      = bfd_simple_get_relocated_section_contents (abfd, msec, NULL, syms);
+	  if (! *section_buffer)
+	    return FALSE;
+	}
+      else
+	{
+	  *section_size = msec->rawsize ? msec->rawsize : msec->size;
+	  *section_buffer = bfd_malloc (*section_size);
+	  if (! *section_buffer)
+	    return FALSE;
+	  if (! bfd_get_section_contents (abfd, msec, *section_buffer,
+					  0, *section_size))
+	    return FALSE;
+	}
+
+      if (section_is_compressed)
+	{
+	  if (! bfd_uncompress_section_contents (section_buffer, section_size))
+	    {
+	      (*_bfd_error_handler) (_("Dwarf Error: unable to decompress %s section."), compressed_section_name);
+	      bfd_set_error (bfd_error_bad_value);
+	      return FALSE;
+	    }
+	}
     }
 
   /* It is possible to get a bad value for the offset into the section