PATCH: libffi: add MIPS O32 DWARF-2 unwind info

[Casey Marshall <csm at gnu dot org>]

The attached patch adds DWARF-2 unwinding info for MIPS ffi_call_O32.
I'm kind of new to both DWARF-2 and MIPS assembly, so this may not be
completely correct. I have tried this on a modified 3.3.3 -- the
changes since then appear to have been only to the SIZEOF_ARG macro --
but have not tried it on a newer version. It seems to work, since
things like `invokethrow.java' work properly for me now.

Note that this is only for the O32 ABI. I think that N32 would be
similar (identical?) to this, but I can't test it.

Also: GCJ emits references to __gcj_personality_v0 in the assembler it
generates, as a "personality" in the CIE. I didn't know if this was
appropriate for the ffi code, so I merely omitted it. Is this ok?

(I wasn't sure where to send this patch, but I suppose GCJ users will
find it useful)

2004-06-23  Casey Marshall <csm@gnu.org>

	* src/mips/o32.S: added unwind info for `ffi_call_O32'.

-- 
Casey Marshall || csm@gnu.org

Index: src/mips/o32.S
===================================================================
RCS file: /cvsroot/gcc/gcc/libffi/src/mips/o32.S,v
retrieving revision 1.3
diff -u -r1.3 o32.S
--- src/mips/o32.S	21 Oct 2003 19:01:56 -0000	1.3
+++ src/mips/o32.S	23 Jun 2004 19:51:11 -0000
@@ -42,13 +42,17 @@
 	.globl	ffi_call_O32
 	.ent	ffi_call_O32
 ffi_call_O32:	
-
+$LFB0:
 	# Prologue
 	SUBU	$sp, SIZEOF_FRAME			# Frame size
+$LCFI0:
 	REG_S	$fp, SIZEOF_FRAME - 2*FFI_SIZEOF_ARG($sp)	# Save frame pointer
+$LCFI1:
 	REG_S	ra, SIZEOF_FRAME - 1*FFI_SIZEOF_ARG($sp)	# Save return address
+$LCFI2:
 	move	$fp, $sp
 
+$LCFI3:
 	move	t9, callback	# callback function pointer
 	REG_S	flags, SIZEOF_FRAME + 3*FFI_SIZEOF_ARG($fp) # flags
 
@@ -167,6 +171,51 @@
 	ADDU	$sp, SIZEOF_FRAME		      # Fix stack pointer
 	j	ra
 
+$LFE0:
 	.end	ffi_call_O32
-	
+
+	.section	.eh_frame,"a",@progbits
+$Lframe0:
+	.4byte	$LECIE0-$LSCIE0	 # Length of Common Information Entry
+$LSCIE0:
+	.4byte	0x0	 # CIE Identifier Tag
+	.byte	0x1	 # CIE Version
+	.ascii "zR\0"	 # CIE Augmentation
+	.uleb128 0x1	 # CIE Code Alignment Factor
+	.sleb128 4	 # CIE Data Alignment Factor
+	.byte	0x1f	 # CIE RA Column
+	.uleb128 0x1	 # Augmentation size
+	.byte	0x1b	 # FDE Encoding (pcrel sdata4)
+	.byte	0xc	 # DW_CFA_def_cfa
+	.uleb128 0x1d
+	.uleb128 0x0
+	.align	2
+$LECIE0:
+$LSFDE0:
+	.4byte	$LEFDE0-$LASFDE0	 # FDE Length
+$LASFDE0:
+	.4byte	$LASFDE0-$Lframe0	 # FDE CIE offset
+	.4byte	$LFB0-.	 # FDE initial location
+	.4byte	$LFE0-$LFB0	 # FDE address range
+	.uleb128 0x0	 # Augmentation size
+	.byte	0x4	 # DW_CFA_advance_loc4
+	.4byte	$LCFI0-$LFB0
+	.byte	0xe	 # DW_CFA_def_cfa_offset
+	.uleb128 0x18
+	.byte	0x4	 # DW_CFA_advance_loc4
+	.4byte	$LCFI2-$LCFI0
+	.byte	0x11	 # DW_CFA_offset_extended_sf
+	.uleb128 0x1e
+	.sleb128 -2
+	.byte	0x11	 # DW_CFA_offset_extended_sf
+	.uleb128 0x1f
+	.sleb128 -1
+	.byte	0x4	 # DW_CFA_advance_loc4
+	.4byte	$LCFI3-$LCFI2
+	.byte	0xc	 # DW_CFA_def_cfa
+	.uleb128 0x1e
+	.uleb128 0x18
+	.align	2
+$LEFDE0:
+
 #endif