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x86_64 ABI: Handle va_arg arguments with alignment > 8.

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llvm-svn: 64701
This commit is contained in:
Daniel Dunbar
2009-02-16 23:38:56 +00:00
parent 6e8c07d0ea
commit f2c6198eef
1 changed files with 14 additions and 3 deletions
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17
clang/lib/CodeGen/CGCall.cpp
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@@ -896,11 +896,22 @@ static llvm::Value *EmitVAArgFromMemory(llvm::Value *VAListAddr,
// 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.