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[RFC][ARM] Naming for new switch to check for mixed hardfloat/softfloat compat
- From: Thomas Preudhomme <robotux at celest dot fr>
- To: <gcc at gcc dot gnu dot org>
- Date: Tue, 04 Mar 2014 15:02:00 +0800
- Subject: [RFC][ARM] Naming for new switch to check for mixed hardfloat/softfloat compat
- Authentication-results: sourceware.org; auth=none
[Please CC me as I'm not subscribed to this list]
Hi there,
I'm currently working on adding a switch to check whether public
function involve float parameters or return values. Such a check would
be useful for people trying to write code that is compatible with both
base standard (softfloat) and standard variant (hardfloat) ARM calling
convention. I also intend to set the ELF attribute Tag_ABI_VFP_args to
value 3 (code compatible with both ABI) so this check would allow to
make sure such value would be set.
I initially thought about reusing -mfloat-abi with the value none for
that purpose since it would somehow define a new ABI where no float can
be used. However, it would then not be possible to forbit float in
public interface with the use of VFP instructions for float arithmetic
(softfp) because this switch conflates the float ABI with the use of a
floating point unit for float arithmetic. Also, gcc passes -mfloat-abi
down to the assembler and that would mean teaching the assembler about
-mfloat-abi=none as well.
I thus think that a new switch would be better and am asking for your
opinion about it as I would like this functionality to incorporate gcc
codebase.
Best regards,
Thomas Preud'homme