[cfe-commits] [llvm-commits] [PATCH] ARM ABI: handle varargs with vector types.
Eli Friedman
eli.friedman at gmail.com
Mon Oct 15 17:11:30 PDT 2012
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.)
+ if (Ty->getAs<VectorType>() && ((Size == 8 && TyAlign < 8) ||
+ (Size >= 16 && TyAlign < 16))) {
+ // We can't directly cast ap.cur to pointer to a vector type, since ap.cur
+ // may not be correctly aligned for the vector type. We create an aligned
+ // temporary space and copy the content over from ap.cur to the temporary
+ // space. This is necessary if TyAlign < 8 for Size == 8, or
+ // TyAlign < 16 for Size >= 16.
The general rule here is something like "TyAlign <
CGF.getContext().getTypeAlign(Ty) / 8" (i.e. the natural alignment of
the type is greater than the argument-passing alignment).
-Eli
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