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.
Thanks, Manman > > + if (Ty->getAs<VectorType>() && > > Same here. > > -Eli _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
