[PATCH] --gc-sections and .gnu.linkonce.t.* sections

[Eric Botcazou <ebotcazou at adacore dot com>]

Hi Alan,

This is the patch you pre-approved a few weeks ago, which teaches the linker 
to keep the .gcc_except_table.* sections in presence of the corresponding
.gnu.linkonce.t.* sections.  It's needed with GCC 4.3exp when COMDAT groups 
are not used.  Next I'll submit the GCC patch to detect the fixed linker. :-)

Tested on i586-suse-linux.  OK for mainline?  What about 2.17 branch?

Btw, now that there is an (experimental) FSF compiler with the support, do you 
want me to write a few testcases for the improved --gc-sections?  If so, in 
which directory should I put them?


2006-12-10  Eric Botcazou  <ebotcazou@adacore.com>

bfd/	
	* elflink.c (bfd_elf_gc_sections): Also search for corresponding
	sections with .gnu.linkonce.t. prefix.


-- 
Eric Botcazou

Index: elflink.c
===================================================================
RCS file: /cvs/src/src/bfd/elflink.c,v
retrieving revision 1.240
diff -u -p -r1.240 elflink.c
--- elflink.c	7 Dec 2006 13:32:00 -0000	1.240
+++ elflink.c	10 Dec 2006 08:31:42 -0000
@@ -9809,13 +9809,15 @@ bfd_elf_gc_sections (bfd *abfd, struct b
       if (bfd_get_flavour (sub) != bfd_target_elf_flavour)
 	continue;
 
-      /* Keep .gcc_except_table.* if the associated .text.* is
+      /* Keep .gcc_except_table.* if the associated .text.* (or the
+	 associated .gnu.linkonce.t.* if .text.* doesn't exist) is
 	 marked.  This isn't very nice, but the proper solution,
 	 splitting .eh_frame up and using comdat doesn't pan out
 	 easily due to needing special relocs to handle the
 	 difference of two symbols in separate sections.
 	 Don't keep code sections referenced by .eh_frame.  */
 #define TEXT_PREFIX			".text."
+#define TEXT_PREFIX2			".gnu.linkonce.t."
 #define GCC_EXCEPT_TABLE_PREFIX		".gcc_except_table."
       for (o = sub->sections; o != NULL; o = o->next)
 	if (!o->gc_mark && o->gc_mark_from_eh && (o->flags & SEC_CODE) == 0)
@@ -9825,15 +9827,30 @@ bfd_elf_gc_sections (bfd *abfd, struct b
 		char *fn_name;
 		const char *sec_name;
 		asection *fn_text;
-		unsigned o_name_prefix_len  = strlen (GCC_EXCEPT_TABLE_PREFIX);
-		unsigned fn_name_prefix_len = strlen (TEXT_PREFIX);
+		unsigned o_name_prefix_len , fn_name_prefix_len, tmp;
 
+		o_name_prefix_len = strlen (GCC_EXCEPT_TABLE_PREFIX);
 		sec_name = o->name + o_name_prefix_len;
-		fn_name = bfd_malloc (strlen (sec_name) + fn_name_prefix_len + 1);
+		fn_name_prefix_len = strlen (TEXT_PREFIX);
+		tmp = strlen (TEXT_PREFIX2);
+		if (tmp > fn_name_prefix_len)
+		  fn_name_prefix_len = tmp;
+		fn_name
+		  = bfd_malloc (fn_name_prefix_len + strlen (sec_name) + 1);
 		if (fn_name == NULL)
 		  return FALSE;
+
+		/* Try the first prefix.  */
 		sprintf (fn_name, "%s%s", TEXT_PREFIX, sec_name);
 		fn_text = bfd_get_section_by_name (sub, fn_name);
+
+		/* Try the second prefix.  */
+		if (fn_text == NULL)
+		  {
+		    sprintf (fn_name, "%s%s", TEXT_PREFIX2, sec_name);
+		    fn_text = bfd_get_section_by_name (sub, fn_name);
+		  }
+
 		free (fn_name);
 		if (fn_text == NULL || !fn_text->gc_mark)
 		  continue;