PATCH: Fix 32bit coredump read on Linux/AVX

["H.J. Lu" <hongjiu.lu@intel.com>]

Hi,

This patch:

http://sourceware.org/ml/gdb-patches/2010-04/msg00276.html

breaks 32bit coredump read on Linux/AVX since we only dump .reg and
.reg-xstate sections on AVX. But i386_linux_core_read_description
checks .reg2 and .reg-xfp sections first. Since there are no
.reg2 and .reg-xfp sections, NULL is returned and SSE target is used.
This patch changes the section check order to .reg-xstate, .reg-xfp,
.reg2.  OK to install?

Thanks.


H.J.
---
2010-04-19  H.J. Lu  <hongjiu.lu@intel.com>

	* amd64-linux-tdep.c (amd64_linux_core_read_description): Always
	use xcr0 from i386_linux_core_read_xcr0.

	* i386-linux-tdep.c (i386_linux_core_read_xcr0): Check .reg-xfp
	and .reg2 sections for SSE and MMX.
	(i386_linux_core_read_description): Always use xcr0 from
	i386_linux_core_read_xcr0.

diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c
index f249d5d..e66c08e 100644
--- a/gdb/amd64-linux-tdep.c
+++ b/gdb/amd64-linux-tdep.c
@@ -1269,14 +1269,9 @@ amd64_linux_core_read_description (struct gdbarch *gdbarch,
 				  struct target_ops *target,
 				  bfd *abfd)
 {
-  asection *section = bfd_get_section_by_name (abfd, ".reg2");
-  uint64_t xcr0;
-
-  if (section == NULL)
-    return NULL;
-
   /* Linux/x86-64.  */
-  xcr0 = i386_linux_core_read_xcr0 (gdbarch, target, abfd);
+  uint64_t xcr0 = i386_linux_core_read_xcr0 (gdbarch, target, abfd);
+  gdb_assert (xcr0 != 0);
   if ((xcr0 & I386_XSTATE_AVX_MASK) == I386_XSTATE_AVX_MASK)
     return tdesc_amd64_avx_linux;
   else
diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c
index 5952153..750e039 100644
--- a/gdb/i386-linux-tdep.c
+++ b/gdb/i386-linux-tdep.c
@@ -610,8 +610,12 @@ i386_linux_core_read_xcr0 (struct gdbarch *gdbarch,
 	  xcr0 = bfd_get_64 (abfd, contents);
 	}
     }
-  else
+  else if (bfd_get_section_by_name (abfd, ".reg-xfp") != NULL)
     xcr0 = I386_XSTATE_SSE_MASK;
+  else if (bfd_get_section_by_name (abfd, ".reg2") != NULL)
+    xcr0 = I386_XSTATE_X87_MASK;
+  else
+    xcr0 = 0;
 
   return xcr0;
 }
@@ -623,22 +627,20 @@ i386_linux_core_read_description (struct gdbarch *gdbarch,
 				  struct target_ops *target,
 				  bfd *abfd)
 {
-  asection *section = bfd_get_section_by_name (abfd, ".reg2");
-  uint64_t xcr0;
-
-  if (section == NULL)
-    return NULL;
-
-  section = bfd_get_section_by_name (abfd, ".reg-xfp");
-  if (section == NULL)
-    return tdesc_i386_mmx_linux;
+  uint64_t xcr0 = i386_linux_core_read_xcr0 (gdbarch, target, abfd);
 
   /* Linux/i386.  */
-  xcr0 = i386_linux_core_read_xcr0 (gdbarch, target, abfd);
-  if ((xcr0 & I386_XSTATE_AVX_MASK) == I386_XSTATE_AVX_MASK)
-    return tdesc_i386_avx_linux;
-  else
-    return tdesc_i386_linux;
+  switch ((xcr0 & I386_XSTATE_AVX_MASK))
+    {
+    case I386_XSTATE_AVX_MASK:
+      return tdesc_i386_avx_linux;
+    case I386_XSTATE_SSE_MASK:
+      return tdesc_i386_linux;
+    case I386_XSTATE_X87_MASK:
+      return tdesc_i386_mmx_linux;
+    default:
+      return NULL;
+    }
 }
 
 static void