fix Xtensa ld's handling of XCC exception tables

[Bob Wilson <bwilson at tensilica dot com>]

Tensilica's XCC compiler uses its own format for C++ exception tables.  These 
tables go in .xt_except_table and .xt_except_desc sections, or the 
.gnu.linkonce.e.* and .gnu.linkonce.h.* versions.  (Yes, ".e" and ".h" were not 
very good choices for those section names, but they're hard to change now.) 
I've committed this patch to make ld ignore relocations from these tables to 
text that is not included in the link.

bfd/
	* elf32-xtensa.c (elf_xtensa_action_discarded): New.
	(elf_backend_action_discarded): Define.
ld/
	* emultempl/xtensaelf.em (is_inconsistent_linkonce_section): Check
	for linkonce XCC exception tables (".e" and ".h").

Index: bfd/elf32-xtensa.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-xtensa.c,v
retrieving revision 1.72
diff -u -r1.72 elf32-xtensa.c
--- bfd/elf32-xtensa.c	11 Oct 2006 22:16:50 -0000	1.72
+++ bfd/elf32-xtensa.c	12 Oct 2006 18:55:09 -0000
@@ -2969,6 +2969,19 @@
   return xtensa_is_property_section (sec);
 }
 
+
+static unsigned int
+elf_xtensa_action_discarded (asection *sec)
+{
+  if (strcmp (".xt_except_table", sec->name) == 0)
+    return 0;
+
+  if (strcmp (".xt_except_desc", sec->name) == 0)
+    return 0;
+
+  return _bfd_elf_default_action_discarded (sec);
+}
+
 
 /* Support for core dump NOTE sections.  */
 
@@ -9832,5 +9845,6 @@
 #define elf_backend_relocate_section	     elf_xtensa_relocate_section
 #define elf_backend_size_dynamic_sections    elf_xtensa_size_dynamic_sections
 #define elf_backend_special_sections	     elf_xtensa_special_sections
+#define elf_backend_action_discarded	     elf_xtensa_action_discarded
 
 #include "elf32-target.h"
Index: ld/emultempl/xtensaelf.em
===================================================================
RCS file: /cvs/src/src/ld/emultempl/xtensaelf.em,v
retrieving revision 1.15
diff -u -r1.15 xtensaelf.em
--- ld/emultempl/xtensaelf.em	16 Sep 2006 18:12:16 -0000	1.15
+++ ld/emultempl/xtensaelf.em	12 Oct 2006 18:55:09 -0000
@@ -1184,7 +1184,7 @@
 }
 
 
-/* Strip out any linkonce literal sections or property tables where the
+/* Strip out any linkonce property tables or XCC exception tables where the
    associated linkonce text is from a different object file.  Normally,
    a matching set of linkonce sections is taken from the same object file,
    but sometimes the files are compiled differently so that some of the
@@ -1199,17 +1199,22 @@
 {
   bfd *abfd = sec->owner;
   const char *sec_name = bfd_get_section_name (abfd, sec);
-  const char *name = 0;
+  const char *name;
 
   if ((bfd_get_section_flags (abfd, sec) & SEC_LINK_ONCE) == 0
       || strncmp (sec_name, ".gnu.linkonce.", linkonce_len) != 0)
     return FALSE;
 
-  /* Check if this is an Xtensa property section.  */
-  if (CONST_STRNEQ (sec_name + linkonce_len, "p."))
-    name = sec_name + linkonce_len + 2;
-  else if (CONST_STRNEQ (sec_name + linkonce_len, "prop."))
-    name = strchr (sec_name + linkonce_len + 5, '.') + 1;
+  /* Check if this is an Xtensa property section or an exception table
+     for Tensilica's XCC compiler.  */
+  name = sec_name + linkonce_len;
+  if (CONST_STRNEQ (name, "prop."))
+    name = strchr (name + 5, '.') + 1;
+  else if (name[1] == '.'
+	   && (name[0] == 'p' || name[0] == 'e' || name[0] == 'h'))
+    name += 2;
+  else
+    name = 0;
 
   if (name)
     {