[PATCH] don't include symbols from S_ATTR_NO_TOC sections in mach-o canonical symtab output

[Nathan Froyd <froydnj at mozilla dot com>]

Hi,

Generating static library archives with binutils and comparing them with
archives produced by Apple's tools reveals one significant difference:
those produced by Apple's tools are significantly smaller.  binutils
includes many ${SYMBOL_NAME}.eh symbols in the archive table of contents,
whereas Apple's tools do not.

This difference is due to the .eh symbols living in the .eh_frame section,
which is tagged with the Mach-O section flag S_ATTR_NO_TOC.  This flag
instructs the archiver to not include symbols from such a section in the
table of contents for an archive.

The patch below changes bfd_mach_o_canonicalize_symtab to respect this flag.

Tested on x86_64-apple-darwin11, no regressions.  OK to checkin?

-Nathan

	* mach-o.c (bfd_mach_o_canonicalize_symtab): Respect the
	BFD_MACH_O_S_ATTR_NO_TOC flag on symbol sections.
---
 bfd/mach-o.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/bfd/mach-o.c b/bfd/mach-o.c
index 32e48ac..095afeb 100644
--- a/bfd/mach-o.c
+++ b/bfd/mach-o.c
@@ -630,7 +630,7 @@ bfd_mach_o_canonicalize_symtab (bfd *abfd, asymbol **alocation)
   bfd_mach_o_data_struct *mdata = bfd_mach_o_get_data (abfd);
   long nsyms = bfd_mach_o_count_symbols (abfd);
   bfd_mach_o_symtab_command *sym = mdata->symtab;
-  unsigned long j;
+  unsigned long i, j;
 
   if (nsyms < 0)
     return nsyms;
@@ -651,12 +651,23 @@ bfd_mach_o_canonicalize_symtab (bfd *abfd, asymbol **alocation)
 
   BFD_ASSERT (sym->symbols != NULL);
 
-  for (j = 0; j < sym->nsyms; j++)
-    alocation[j] = &sym->symbols[j].symbol;
+  for (i = 0, j = 0; j < sym->nsyms; j++)
+    {
+      bfd_mach_o_asymbol *asym = &sym->symbols[j];
+      if (asym->n_sect != 0)
+	{
+	  bfd_mach_o_section *sect = mdata->sections[asym->n_sect-1];
+	  if (sect->flags & BFD_MACH_O_S_ATTR_NO_TOC)
+	    continue;
+	}
 
-  alocation[j] = NULL;
+      alocation[i] = &asym->symbol;
+      i++;
+    }
+
+  alocation[i] = NULL;
 
-  return nsyms;
+  return i;
 }
 
 /* Create synthetic symbols for indirect symbols.  */
-- 
1.7.9.5