Re: [PATCH] Workaround ARM VFP issue

[Kyle Tinker <ktinker@workforcesoftware.com>]

Chung-Lin:

First, sorry for the large (3 month) delay.

I've applied the patch and gotten it to compile on our system!  THANK YOU!

We had to define the __SOFTFP__ cflag to get it to compile correctly, 
but the patch worked great once we did that.

Sorry our toolchain is so old...  performance is always a consideration, 
but we shouldn't be making THAT many libffi calls for the changes you 
made to matter.  I certainly wouldn't optimize your code for the sake of 
a toolchain that predates 2005.

Thanks,
*Kyle Tinker* *|* *Software Development Manager* *|* *WorkForce Software*

WorkForce Software — Mitigating Complexity — Ensuring Compliance
— Enabling Strategic HR


From: Chung-Lin Tang <cltang@codesourcery.com>
Sent: Tue, Mar 06, 2012 7:37 AM
To: libffi-discuss@sourceware.org <libffi-discuss@sourceware.org>
CC: "green@moxielogic.com" <green@moxielogic.com>, Kyle Tinker 
<ktinker@workforcesoftware.com>
Subject: [PATCH] Workaround ARM VFP issue


> 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.