[PATCH]: gold sparc unaligned...

[David Miller]

From: Eric Botcazou <ebotcazou@adacore.com>
Date: Tue, 9 Feb 2010 17:14:11 +0100

>> I really have no idea.  I doubt many people test with GAS but not GNU
>> ld on Solaris.
> 
> We do it all the time, the Solaris assembler is not very well maintained and 
> the GNU linker doesn't have all the features of the Sun linker on Solaris 10.

I'm steadily trying to close those gaps.  I actually enjoy hacking on
these tools so just tell me what the most important stuff is. :-)

What assembler features are missing?  I thought I had added the most
important ones already.

After I finish GOTDATA_OP optimization support (will post the patch
for that today) the only missing linker features should be the fortran
data compression hacks.  Are there any others you really need?

> So it would be better to do something like:
> 
> 2006-11-27  Eric Botcazou  <ebotcazou@adacore.com>
> 
> 	* config/tc-sparc.c (tc_gen_reloc): Turn aligned relocs into
> 	their unaligned counterparts in debugging sections.

This is a good idea, but overkill.  We have access to the
relocation information, so we can see whether the offset
is going to be unaligned or not.

I cooked up the following patch yesterday while looking
into these issues.  Want me to commit it?

gas/

2010-02-09  David S. Miller  <davem@davemloft.net>

	* config/tc-sparc.c (cons_fix_new_sparc): Use unaligned reloc
	variant if relocation offset is unaligned.

diff --git a/gas/config/tc-sparc.c b/gas/config/tc-sparc.c
index 26ecc86..d65c71a 100644
--- a/gas/config/tc-sparc.c
+++ b/gas/config/tc-sparc.c
@@ -4443,15 +4443,41 @@ cons_fix_new_sparc (fragS *frag,
 		    expressionS *exp)
 {
   bfd_reloc_code_real_type r;
+  int unaligned = 0;
 
-  r = (nbytes == 1 ? BFD_RELOC_8 :
-       (nbytes == 2 ? BFD_RELOC_16 :
-	(nbytes == 4 ? BFD_RELOC_32 : BFD_RELOC_64)));
+  switch (nbytes)
+    {
+    case 1:
+      r = BFD_RELOC_8;
+      break;
+
+    case 2:
+      r = BFD_RELOC_16;
+      unaligned = (where & 1);
+      break;
+
+    case 4:
+      r = BFD_RELOC_32;
+      unaligned = (where & 3);
+      break;
+
+    case 8:
+      r = BFD_RELOC_64;
+      unaligned = (where & 7);
+      break;
+
+    default:
+      abort ();
+    }
 
   if (target_little_endian_data
       && nbytes == 4
       && now_seg->flags & SEC_ALLOC)
-    r = BFD_RELOC_SPARC_REV32;
+    {
+      if (unaligned)
+	abort ();
+      r = BFD_RELOC_SPARC_REV32;
+    }
 
   if (sparc_cons_special_reloc)
     {
@@ -4477,7 +4503,8 @@ cons_fix_new_sparc (fragS *frag,
 	  case 8: r = BFD_RELOC_SPARC_TLS_DTPOFF64; break;
 	  }
     }
-  else if (sparc_no_align_cons)
+  else if (sparc_no_align_cons
+	   || unaligned)
     {
       switch (nbytes)
 	{