Re: [RFC] Linux-specific ppc32 ABI

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> Date: Fri, 1 Feb 2008 14:38:39 -0800
> From: Joel Brobecker <brobecker@adacore.com>
> 
> Hi Mark,
> 
> > How about the attached diff?
> 
> Sounds like everyone is happy with the patch you suggested. Thiago
> just mentioned one nit in your comments (repeated below). Can the patch
> be checked in?  We'd like to have it for the release.
> 

I tweaked the comment a bit more.  See below what I comitted.

Thiago/Luis, can you commit the testsuite change?


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>
	Luis Machado  <luisgpm@br.ibm.com>
	Thiago Jung Bauermann  <bauerman@br.ibm.com>	

	* ppc-sysv-tdep.c (ppc_sysv_abi_push_dummy_call): Pass floats that
	don't fit into registerson the stack the way GCC does.

Index: ppc-sysv-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ppc-sysv-tdep.c,v
retrieving revision 1.47
diff -u -p -r1.47 ppc-sysv-tdep.c
--- ppc-sysv-tdep.c 1 Feb 2008 15:04:18 -0000 1.47
+++ ppc-sysv-tdep.c 2 Feb 2008 00:07:14 -0000
@@ -129,17 +129,21 @@ ppc_sysv_abi_push_dummy_call (struct gdb
 		}
 	      else
 		{
-		  /* SysV ABI converts floats to doubles before
-		     writing them to an 8 byte aligned stack location.  */
-		  argoffset = align_up (argoffset, 8);
+		  /* The SysV ABI tells us to convert floats to
+		     doubles before writing them to an 8 byte aligned
+		     stack location.  Unfortunately GCC does not do
+		     that, and stores floats into 4 byte aligned
+		     locations without converting them to doubles.
+		     Since there is no know compiler that actually
+		     follows the ABI here, we implement the GCC
+		     convention.  */
+
+		  /* Align to 4 bytes or 8 bytes depending on the type of
+		     the argument (float or double).  */
+		  argoffset = align_up (argoffset, len);
 		  if (write_pass)
-		    {
-		      char memval[8];
-		      convert_typed_floating (val, type, memval,
-					      builtin_type_ieee_double);
 		      write_memory (sp + argoffset, val, len);
-		    }
-		  argoffset += 8;
+		  argoffset += len;
 		}
 	    }
 	  else if (TYPE_CODE (type) == TYPE_CODE_FLT