On Tue, Oct 16, 2012 at 11:42 AM, Manman Ren <[email protected]> wrote: > > On Oct 16, 2012, at 11:32 AM, Eli Friedman wrote: > >> On Tue, Oct 16, 2012 at 11:10 AM, manman ren <[email protected]> wrote: >>> >>> On Oct 15, 2012, at 5:59 PM, Eli Friedman <[email protected]> wrote: >>> >>>> On Mon, Oct 15, 2012 at 5:38 PM, Manman Ren <[email protected]> wrote: >>>>> >>>>> On Oct 15, 2012, at 5:34 PM, Eli Friedman wrote: >>>>> >>>>>> On Mon, Oct 15, 2012 at 5:26 PM, Manman Ren <[email protected]> wrote: >>>>>>> >>>>>>> On Oct 15, 2012, at 5:11 PM, Eli Friedman wrote: >>>>>>> >>>>>>>> On Mon, Oct 15, 2012 at 4:46 PM, manman ren <[email protected]> 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". >>>>> >>>>> I don't see code in ARMABIInfo::classifyArgumentType that checks the >>>>> argument-passing alignment. >>>>> The code in the patch is trying to match what the calling convention does >>>>> in the backend: >>>> >>>> Yes, it's a bit tricky because of the implicit contract between clang >>>> and the ARM backend... you basically have to combine the frontend and >>>> backend rules to figure out how the result is actually represented on >>>> the stack. When you do that, it comes out to always 4 for APCS, and I >>>> think it comes out to min(max(naturalAlign, 4), 8) for AAPCS. >>> >>> I think you are right, the patch is updated, please review again :] >> >> + if (Ty->getAs<VectorType>()) { >> >> Why restrict the check to vector types? (This check can have effects >> for other types, e.g. structs containing vectors.) > I want to make sure this patch only touches varargs with vector types. > For other types, we can handle those in a separate patch with additional > testing cases.
Okay. -Eli _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
