Re: Bug of gas (binutils-2.9.1.0.23): Wrong code for SETHI on SPARC

[hjl@lucon.org (H.J. Lu)]

> gas out of binutils-2.9.1.0.23 (and older versions) has a severe bug
> for the SPARC platform (sparc-sun-solaris2.6), i.e. it generates
> wrong code for
> 
>         sethi   0x4000,%i0
> 
> (and probably in all other cases where sethi is used without the
> %hi(...)-construct).
> 
> The sethi instruction has following suggested assembly syntax
> (see SPARC Architecture Manual):
> 
>         sethi   const22,reg
> 
> const22 is a 22-bit constant that is placed by sethi in the most
> significant 22 bits of reg (while it zeroes the 10 least significant
> bits of reg). Therefore we would expect the value 0x100000 in %i0
> after the execution of ``sethi 16384''. Instead of this, gas
> modifies the given constant such that 0x4000 will be found in %i0
> afterwards. This would have been equivalent to
> 
>         sethi %hi(0x4000),%i0
> 

Please try this patch. I know next to nothing about Sparc asm. Please
make sure this patch won't break anything on Sparc and let me know
the result. I hope someone will make a real fix for this bug.

Thanks.


H.J.
----
Fri Apr  2 11:44:49 1999  H.J. Lu  (hjl@gnu.org)

        * config/tc-sparc.c (sparc_ip): Fix "sethi const22,reg".

Index: tc-sparc.c
===================================================================
RCS file: /local/work/cvs/gnu/binutils/gas/config/tc-sparc.c,v
retrieving revision 1.10
diff -u -p -r1.10 tc-sparc.c
--- tc-sparc.c	1999/03/31 17:24:48	1.10
+++ tc-sparc.c	1999/04/02 19:45:21
@@ -1126,6 +1126,7 @@ sparc_ip (str, pinsn)
   unsigned int mask = 0;
   int match = 0;
   int comma = 0;
+  int unary = 0;
   int v9_arg_p;
 
   for (s = str; islower ((unsigned char) *s) || (s > str && *s >= '0' && *s <= '8'); ++s)
@@ -1876,6 +1877,9 @@ sparc_ip (str, pinsn)
 		  };
 		  struct ops *o;
 
+		  /* We have seen "%xx". */
+		  unary = 1;
+
 		  for (o = ops; o->name; o++)
 		    if (strncmp (s + 1, o->name, o->len) == 0)
 		      break;
@@ -1940,6 +1944,21 @@ sparc_ip (str, pinsn)
 		      error_message = ": PC-relative operand can't be a constant";
 		      goto error;
 		    }
+		  else if (strcmp (insn->name, "sethi") == 0
+			   && unary == 0)
+		    /* The sethi instruction has following suggested
+		       assembly syntax (see SPARC Architecture Manual):
+
+			    sethi	const22,reg
+
+		       const22 is a 22-bit constant that is placed by
+		       sethi in the most significant 22 bits of reg
+		       (while it zeroes the 10 least significant bits
+		       of reg). It is different from
+
+			    sethi	%hi(value),reg
+		      */
+		    the_insn.reloc = BFD_RELOC_SPARC22;
 
 		  /* Constants that won't fit are checked in md_apply_fix3
 		     and bfd_install_relocation.