[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

[Evan Cheng]

On Jun 11, 2009, at 4:47 PM, Sandeep Patel wrote:

> 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.).

Ok. Then it makes more sense for it to be a function note. We should  
be able to figure out a way to change calling convention (and other  
subtarget states).

Evan

>
>
> deep
>
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