[PATCH] Workaround ARM VFP issue

[Chung-Lin Tang <cltang@codesourcery.com>]

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This is patch to workaround the issue mentioned in this thread:
http://sourceware.org/ml/libffi-discuss/2012/msg00038.html

The issue is not really that soft-float is broken, but rather the
toolchain used is simply too old, not really because it is old-ABI, but
too old a version of binutils; the .fpu directive, nor VFP instructions
are supported in the assembler, hence even building of the VFP
call/closure shims fail.

This patch is sort of a least attempt to shield away the VFP stuff when
__ARM_EABI__ is not defined. I apologize for such a token workaround, as
it can probably be optimized a bit more, but I just feel it's not
worthwhile; even GCC (recent versions) assumes such assembler features.

Kyle, can you please see if the patch can work for you? If in case it
doesn't, I might also suggest that you try to rebuild your toolchain
with a newer binutils version (at least post circa 2005), which should
at least not fail to build the library.

Thanks,
Chung-Lin

2012-03-06  Chung-Lin Tang  <cltang@codesourcery.com>

	* src/arm/ffi.c (ffi_call): Add __ARM_EABI__ guard around call
	to ffi_call_VFP().
	(ffi_prep_closure_loc): Add __ARM_EABI__ guard around use of
	ffi_closure_VFP.
	* src/arm/sysv.S: Add __ARM_EABI__ guard around VFP code.

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diff --git a/src/arm/ffi.c b/src/arm/ffi.c
index 1f8597d..3ccceb9 100644
--- a/src/arm/ffi.c
+++ b/src/arm/ffi.c
@@ -251,8 +251,10 @@ void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
       break;
 
     case FFI_VFP:
+#ifdef __ARM_EABI__
       ffi_call_VFP (fn, &ecif, cif->bytes, cif->flags, ecif.rvalue);
       break;
+#endif
 
     default:
       FFI_ASSERT(0);
@@ -609,8 +611,10 @@ ffi_prep_closure_loc (ffi_closure* closure,
 
   if (cif->abi == FFI_SYSV)
     closure_func = &ffi_closure_SYSV;
+#ifdef __ARM_EABI__
   else if (cif->abi == FFI_VFP)
     closure_func = &ffi_closure_VFP;
+#endif
   else
     return FFI_BAD_ABI;
     
diff --git a/src/arm/sysv.S b/src/arm/sysv.S
index 60e2ae3..2505305 100644
--- a/src/arm/sysv.S
+++ b/src/arm/sysv.S
@@ -334,7 +334,8 @@ ARM_FUNC_START ffi_closure_SYSV
 
 
 /* Below are VFP hard-float ABI call and closure implementations.
-   Add VFP FPU directive here. */
+   Add VFP FPU directive here. This is only compiled into the library under EABI.  */
+#ifdef __ARM_EABI__
 	.fpu	vfp
 
 	@ r0:   fn
@@ -491,6 +492,7 @@ ARM_FUNC_START ffi_closure_VFP
 .ffi_closure_VFP_end:
 	UNWIND .fnend
         .size    CNAME(ffi_closure_VFP),.ffi_closure_VFP_end-CNAME(ffi_closure_VFP)
+#endif
 
 ENTRY(ffi_arm_trampoline)
 	stmfd sp!, {r0-r3}