[patch] Fix false warning: section .gnu.liblist not found in ...

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

post-7.0 GDB started to print many false warnings on prelink-ed system:

$ ./gdb -nx -ex r echo
...
Reading symbols from /bin/echo...Reading symbols from /usr/lib/debug/bin/echo.debug...
warning: section .gnu.liblist not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.conflict not found in /usr/lib/debug/bin/echo.debug
done.
done.
Starting program: /bin/echo
warning: section .gnu.liblist not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.conflict not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.liblist not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.conflict not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.liblist not found in /usr/lib/debug/bin/echo.debug
warning: section .gnu.conflict not found in /usr/lib/debug/bin/echo.debug

These sections are from prelink and they are not present in the *.debug files.

It is formally a regression by:

commit 3bfec189bb0fa1a2a44f1645dd68a9572e7a841c

2010-01-07  Tristan Gingold  <gingold@adacore.com>

	* symfile.c (build_section_addr_info_from_objfile): New function.
	(symbol_file_add_separate): Don't use offsets from objfile but
	built an addr info.


But I think would be unavoidable even for the unification of PIC+PIE handling.

Found no usable section flag differences for .gnu.liblist vs. for example
.text so used just the section name for the exception.

.gnu.liblist/.gnu.conflict related dumps:

executable:
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [ 6] .gnu.liblist      GNU_LIBLIST     00000000004006b8 0006b8 000028 14   A 28   0  4
  [ 7] .gnu.conflict     RELA            00000000004006e0 0006e0 0001c8 18   A  5   0  8
Program Headers:
  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
  LOAD           0x000000 0x0000000000400000 0x0000000000400000 0x005254 0x005254 R E 0x200000
Dynamic section at offset 0x52c8 contains 24 entries:
  Tag        Type                         Name/Value
 0x000000006ffffef9 (GNU_LIBLIST)        0x4006b8
 0x000000006ffffdf7 (GNU_LIBLISTSZ)      40 (bytes)
 0x000000006ffffef8 (GNU_CONFLICT)       0x4006e0
 0x000000006ffffdf6 (GNU_CONFLICTSZ)     456 (bytes)

library:
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [74] .gnu.liblist      GNU_LIBLIST     0000000000000000 249940 000014 14     75   0  4


No regressions on {x86_64,x86_64-m32,i686}-fedora12-linux-gnu.


Thanks,
Jan


2010-02-13  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* symfile.c (addr_info_make_relative): Move variable sect into a more
	inner block.  New variable name.  Do not warn on ".gnu.liblist" and
	".gnu.conflict".

--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -568,7 +568,6 @@ void
 addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
 {
   asection *lower_sect;
-  asection *sect;
   CORE_ADDR lower_offset;
   int i;
 
@@ -601,7 +600,9 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
     {
       if (addrs->other[i].addr != 0)
 	{
-	  sect = bfd_get_section_by_name (abfd, addrs->other[i].name);
+	  const char *name = addrs->other[i].name;
+	  asection *sect = bfd_get_section_by_name (abfd, name);
+
 	  if (sect)
 	    {
 	      addrs->other[i].addr -= bfd_section_vma (abfd, sect);
@@ -611,8 +612,16 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
 	    }
 	  else
 	    {
-	      warning (_("section %s not found in %s"), addrs->other[i].name,
-		       bfd_get_filename (abfd));
+	      /* These two sections are intentionally loaded into memory from
+		 the DYNAMIC segment and they have both SEC_ALLOC and SEC_LOAD
+		 set in the main executable (not in the library files).  They
+		 are not present in the separate debug info file, though.  */
+
+	      if (!(strcmp (name, ".gnu.liblist") == 0
+		    || strcmp (name, ".gnu.conflict") == 0))
+		warning (_("section %s not found in %s"), addrs->other[i].name,
+			 bfd_get_filename (abfd));
+
 	      addrs->other[i].addr = 0;
 	    }
 	}