This is a backport from upstream libffi so get it working on
ARM with and without VFP

-Khem

Index: mozilla-central/js/src/ctypes/libffi/src/arm/sysv.S
===================================================================
--- mozilla-central.orig/js/src/ctypes/libffi/src/arm/sysv.S
+++ mozilla-central/js/src/ctypes/libffi/src/arm/sysv.S
@@ -1,5 +1,6 @@
 /* -----------------------------------------------------------------------
-   sysv.S - Copyright (c) 1998, 2008 Red Hat, Inc.
+   sysv.S - Copyright (c) 1998, 2008, 2011 Red Hat, Inc.
+	    Copyright (c) 2011 Plausible Labs Cooperative, Inc.
    
    ARM Foreign Function Interface 
 
@@ -39,7 +40,11 @@
 #else
 #define CNAME(x) x
 #endif
+#ifdef __APPLE__
+#define ENTRY(x) .globl CNAME(x); CNAME(x):
+#else
 #define ENTRY(x) .globl CNAME(x); .type CNAME(x),%function; CNAME(x):
+#endif /* __APPLE__ */
 #endif
 
 #ifdef __ELF__
@@ -48,6 +53,12 @@
 #define LSYM(x) x
 #endif
 
+/* Use the SOFTFP return value ABI on Mac OS X, as per the iOS ABI
+  Function Call Guide */
+#ifdef __APPLE__
+#define __SOFTFP__
+#endif
+
 /* We need a better way of testing for this, but for now, this is all 
    we can do.  */
 @ This selects the minimum architecture level required.
@@ -105,21 +116,33 @@
 	.align 0
 	.thumb
 	.thumb_func
+#ifdef __APPLE__
+	ENTRY($0)
+#else
 	ENTRY(\name)
+#endif
 	bx	pc
 	nop
 	.arm
 	UNWIND .fnstart
 /* A hook to tell gdb that we've switched to ARM mode.  Also used to call
    directly from other local arm routines.  */
-_L__\name:		
+#ifdef __APPLE__
+_L__$0:
+#else
+_L__\name:
+#endif
 .endm
 #else
 .macro	ARM_FUNC_START name
 	.text
 	.align 0
 	.arm
+#ifdef __APPLE__
+	ENTRY($0)
+#else
 	ENTRY(\name)
+#endif
 	UNWIND .fnstart
 .endm
 #endif
@@ -141,8 +164,7 @@ _L__\name:		
 #endif
 .endm
 
-
-	@ r0:   fn
+	@ r0:   ffi_prep_args
 	@ r1:   &ecif
 	@ r2:   cif->bytes
 	@ r3:   fig->flags
@@ -222,12 +244,98 @@ ARM_FUNC_START ffi_call_SYSV
 #endif
 
 LSYM(Lepilogue):
-	RETLDM	"r0-r3,fp"
+#if defined (__INTERWORKING__)
+	ldmia   sp!, {r0-r3,fp, lr}
+	bx	lr
+#else
+	ldmia   sp!, {r0-r3,fp, pc}
+#endif
 
 .ffi_call_SYSV_end:
 	UNWIND .fnend
+#ifdef __ELF__
         .size    CNAME(ffi_call_SYSV),.ffi_call_SYSV_end-CNAME(ffi_call_SYSV)
+#endif
+
+
+/*
+	unsigned int FFI_HIDDEN
+	ffi_closure_SYSV_inner (closure, respp, args)
+	     ffi_closure *closure;
+	     void **respp;
+  	     void *args;
+*/
+
+ARM_FUNC_START ffi_closure_SYSV
+	UNWIND .pad #16
+	add	ip, sp, #16
+	stmfd	sp!, {ip, lr}
+	UNWIND .save	{r0, lr}
+	add	r2, sp, #8
+	UNWIND .pad #16
+	sub	sp, sp, #16
+	str	sp, [sp, #8]
+	add	r1, sp, #8
+	bl	CNAME(ffi_closure_SYSV_inner)
+	cmp	r0, #FFI_TYPE_INT
+	beq	.Lretint
+
+	cmp	r0, #FFI_TYPE_FLOAT
+#if defined(__SOFTFP__) || defined(__ARM_EABI__)
+	beq	.Lretint
+#else
+	beq	.Lretfloat
+#endif
+
+	cmp	r0, #FFI_TYPE_DOUBLE
+#if defined(__SOFTFP__) || defined(__ARM_EABI__)
+	beq	.Lretlonglong
+#else
+	beq	.Lretdouble
+#endif
+
+	cmp	r0, #FFI_TYPE_LONGDOUBLE
+#if defined(__SOFTFP__) || defined(__ARM_EABI__)
+	beq	.Lretlonglong
+#else
+	beq	.Lretlongdouble
+#endif
+
+	cmp	r0, #FFI_TYPE_SINT64
+	beq	.Lretlonglong
+.Lclosure_epilogue:
+	add	sp, sp, #16
+	ldmfd	sp, {sp, pc}
+.Lretint:
+	ldr	r0, [sp]
+	b	.Lclosure_epilogue
+.Lretlonglong:
+	ldr	r0, [sp]
+	ldr	r1, [sp, #4]
+	b	.Lclosure_epilogue
 
+#if !defined(__SOFTFP__) && !defined(__ARM_EABI__)
+.Lretfloat:
+	ldfs	f0, [sp]
+	b	.Lclosure_epilogue
+.Lretdouble:
+	ldfd	f0, [sp]
+	b	.Lclosure_epilogue
+.Lretlongdouble:
+	ldfd	f0, [sp]
+	b	.Lclosure_epilogue
+#endif
+
+.ffi_closure_SYSV_end:
+	UNWIND .fnend
+#ifdef __ELF__
+        .size    CNAME(ffi_closure_SYSV),.ffi_closure_SYSV_end-CNAME(ffi_closure_SYSV)
+#endif
+
+
+/* Below are VFP hard-float ABI call and closure implementations.
+   Add VFP FPU directive here. */
+	.fpu	vfp
 
 	@ r0:   fn
 	@ r1:   &ecif
@@ -294,7 +402,7 @@ LSYM(Lbase_args):
 	@ assume no return value.
 	cmp	r2, #0
 	beq	LSYM(Lepilogue_vfp)
-	
+
 	cmp	r3, #FFI_TYPE_INT
 	streq	r0, [r2]
 	beq	LSYM(Lepilogue_vfp)
@@ -321,79 +429,6 @@ LSYM(Lepilogue_vfp):
 .ffi_call_VFP_end:
 	UNWIND .fnend
         .size    CNAME(ffi_call_VFP),.ffi_call_VFP_end-CNAME(ffi_call_VFP)
-	
-	
-/*
-	unsigned int FFI_HIDDEN
-	ffi_closure_SYSV_inner (closure, respp, args)
-	     ffi_closure *closure;
-	     void **respp;
-  	     void *args;
-*/
-
-ARM_FUNC_START ffi_closure_SYSV
-	UNWIND .pad #16
-	add	ip, sp, #16
-	stmfd	sp!, {ip, lr}
-	UNWIND .save	{r0, lr}
-	add	r2, sp, #8
-	.pad #16
-	sub	sp, sp, #16
-	str	sp, [sp, #8]
-	add	r1, sp, #8
-	bl	ffi_closure_SYSV_inner
-	cmp	r0, #FFI_TYPE_INT
-	beq	.Lretint
-
-	cmp	r0, #FFI_TYPE_FLOAT
-#if defined(__SOFTFP__) || defined(__ARM_EABI__)
-	beq	.Lretint
-#else
-	beq	.Lretfloat
-#endif
-
-	cmp	r0, #FFI_TYPE_DOUBLE
-#if defined(__SOFTFP__) || defined(__ARM_EABI__)
-	beq	.Lretlonglong
-#else
-	beq	.Lretdouble
-#endif
-
-	cmp	r0, #FFI_TYPE_LONGDOUBLE
-#if defined(__SOFTFP__) || defined(__ARM_EABI__)
-	beq	.Lretlonglong
-#else
-	beq	.Lretlongdouble
-#endif
-
-	cmp	r0, #FFI_TYPE_SINT64
-	beq	.Lretlonglong
-.Lclosure_epilogue:
-	add	sp, sp, #16
-	ldmfd	sp, {sp, pc}
-.Lretint:
-	ldr	r0, [sp]
-	b	.Lclosure_epilogue
-.Lretlonglong:
-	ldr	r0, [sp]
-	ldr	r1, [sp, #4]
-	b	.Lclosure_epilogue
-
-#if !defined(__SOFTFP__) && !defined(__ARM_EABI__)
-.Lretfloat:
-	ldfs	f0, [sp]
-	b	.Lclosure_epilogue
-.Lretdouble:
-	ldfd	f0, [sp]
-	b	.Lclosure_epilogue
-.Lretlongdouble:
-	ldfd	f0, [sp]
-	b	.Lclosure_epilogue
-#endif
-
-.ffi_closure_SYSV_end:
-	UNWIND .fnend
-        .size    CNAME(ffi_closure_SYSV),.ffi_closure_SYSV_end-CNAME(ffi_closure_SYSV)
 
 
 ARM_FUNC_START ffi_closure_VFP
@@ -405,7 +440,7 @@ ARM_FUNC_START ffi_closure_VFP
 	UNWIND .save	{r0, lr}
 	add	r2, sp, #72
 	add	r3, sp, #8
-	.pad #72
+	UNWIND .pad #72
 	sub	sp, sp, #72
 	str	sp, [sp, #64]
 	add	r1, sp, #64
@@ -460,3 +495,4 @@ ARM_FUNC_START ffi_closure_VFP
 #if defined __ELF__ && defined __linux__
 	.section	.note.GNU-stack,"",%progbits
 #endif
+