x86_64 ABI: Handle va_arg arguments with alignment > 8.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64701 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 708c717..6f22adf 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -896,11 +896,22 @@
// AMD64-ABI 3.5.7p5: Step 7. Align l->overflow_arg_area upwards to a 16
// byte boundary if alignment needed by type exceeds 8 byte boundary.
- uint64_t Align = llvm::NextPowerOf2(CGF.getContext().getTypeAlign(Ty) / 8);
+ uint64_t Align = CGF.getContext().getTypeAlign(Ty) / 8;
if (Align > 8) {
- // Note align to type alignment instead of assuming it must be 16.
+ // Note that we follow the ABI & gcc here, even though the type
+ // could in theory have an alignment greater than 16. This case
+ // shouldn't ever matter in practice.
- // FIXME: Implement alignment in x86_64 va_arg.
+ // overflow_arg_area = (overflow_arg_area + 15) & ~15;
+ llvm::Value *Offset = llvm::ConstantInt::get(llvm::Type::Int32Ty, 15);
+ overflow_arg_area = CGF.Builder.CreateGEP(overflow_arg_area, Offset);
+ llvm::Value *AsInt = CGF.Builder.CreatePtrToInt(overflow_arg_area,
+ llvm::Type::Int64Ty);
+ llvm::Value *Mask = llvm::ConstantInt::get(llvm::Type::Int64Ty, ~15LL);
+ overflow_arg_area =
+ CGF.Builder.CreateIntToPtr(CGF.Builder.CreateAnd(AsInt, Mask),
+ overflow_arg_area->getType(),
+ "overflow_arg_area.align");
}
// AMD64-ABI 3.5.7p5: Step 8. Fetch type from l->overflow_arg_area.