[llvm-commits] [llvm] r73095 - in /llvm/trunk: include/llvm/Target/TargetMachine.h include/llvm/Target/TargetOptions.h lib/Target/ARM/ARMCallingConv.td lib/Target/ARM/ARMISelDAGToDAG.cpp lib/Target/ARM/ARMISelLowering.cpp lib/Target/ARM/ARMRegist

[Sandeep Patel]

On Thu, Jun 11, 2009 at 2:33 PM, Bob Wilson<bob.wilson at apple.com> wrote:
>
> On Jun 11, 2009, at 11:52 AM, Evan Cheng wrote:
>>
>> On Jun 11, 2009, at 11:32 AM, Chris Lattner wrote:
>>>
>>> Why not put this into the target triple?  Major ABI issues like this
>>> seem like they belong in the triple.
>>
>> It's not always clear what information we want to encode in triplet.
>> In this case, it seems reasonable to encode float abi in the triplet.
>> But how do we want encode this? Do we want to use it to toggle fp abi
>> for any target, e.g. arm-apple-darwin-apcs?
>
> Since target triples are a GNU thing, it would be a good idea to be
> compatible with GCC on this.  I know that for the base AAPCS ABI GCC
> uses an "eabi" suffix on the OS portion of the triple, e.g., arm-linux-
> gnueabi.
>
> When I last worked on GCC, it had no support for the "hardfloat" AAPCS
> ABI, but I heard that it was added since then.  Does anyone know if
> GCC uses something in the triple ("eabi-hardfloat" suffix??) to
> indicate this?
>
> Since this fp ABI is an extension of AAPCS, it would only make sense
> to allow toggling something in the target triple for targets that use
> AAPCS (not Darwin).

GCC did not change the target triple to indicate use of hard float;
it's still arm-linux-gnueabi. GCC even allows a function attribute to
change the ABI per function in support of kernel development and other
cases where one may need to mix ABIs (e.g. a library that supports
legacy soft float applications, etc.).

deep