[llvm-commits] [PATCH] ARM ABI: handle varargs with vector types.

[Eli Friedman]

On Mon, Oct 15, 2012 at 5:26 PM, Manman Ren <mren at apple.com> wrote:
>
> On Oct 15, 2012, at 5:11 PM, Eli Friedman wrote:
>
>> On Mon, Oct 15, 2012 at 4:46 PM, manman ren <mren at apple.com> wrote:
>>>
>>> The initial patch was updated and separated to two patches (attached).
>>>
>>> The first patch will fix passing legal vector types as varargs:
>>> We make sure the vector is correctly aligned before casting it to the vector type.
>>
>> +  uint64_t Size = CGF.getContext().getTypeSize(Ty) / 8;
>> +  uint64_t TyAlign = CGF.getContext().getTypeAlign(Ty) / 8;
>> +
>> +  // The ABI alignment for vectors is 8 for AAPCS and 4 for APCS.
>> +  if (Ty->getAs<VectorType>() && Size >= 8) {
>> +    if (getABIKind() == ARMABIInfo::AAPCS_VFP ||
>> +        getABIKind() == ARMABIInfo::AAPCS)
>> +      TyAlign = 8;
>> +    else
>> +      TyAlign = 4;
>> +  }
>>
>> We should be using the same rules here we do for argument passing.  In
>> particular, for APCS, the argument-passing type alignment is
>> unconditionally 4.  (This can have effects for structs marked with
>> "__attribute__((aligned(16)))", etc.)
> Is there an interface to query the argument-passing alignment?

Nothing cares about it other than the calling convention code, so
there isn't a general API.  It's basically just "match whatever
ARMABIInfo::classifyArgumentType does".

-Eli