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MS ABI: Use the proper type for inalloca args 

Summary:
The definition of a type later in a translation unit may change it's
type from {}* to (%struct.foo*)*.  Earlier function definitions may use
the former while more recent definitions might use the later.  This is
fine until they interact with one another (like one calling the other).
In these cases, a bitcast is needed because the inalloca must match the
function call but the store to the lvalue which initializes the argument
slot has to match the rvalue's type.

This technique is along the same lines with what the other,
non-inalloca, codepaths perform.

This fixes PR19287.

Reviewers: rnk

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3224

llvm-svn: 205217
This commit is contained in:
David Majnemer 2014-03-31 16:12:47 +00:00
parent 6a0ccfb585
commit 32b57b0a4c
2 changed files with 27 additions and 0 deletions
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7
clang/lib/CodeGen/CGCall.cpp
View File

@ -2603,6 +2603,13 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
// Store the RValue into the argument struct.
llvm::Value *Addr =
Builder.CreateStructGEP(ArgMemory, ArgInfo.getInAllocaFieldIndex());
unsigned AS = Addr->getType()->getPointerAddressSpace();
llvm::Type *MemType = ConvertTypeForMem(I->Ty)->getPointerTo(AS);
// There are some cases where a trivial bitcast is not avoidable. The
// definition of a type later in a translation unit may change it's type
// from {}* to (%struct.foo*)*.
if (Addr->getType() != MemType)
Addr = Builder.CreateBitCast(Addr, MemType);
LValue argLV = MakeAddrLValue(Addr, I->Ty, TypeAlign);
EmitInitStoreOfNonAggregate(*this, RV, argLV);
}

20
clang/test/CodeGenCXX/microsoft-abi-sret-and-byval.cpp
View File

@ -263,3 +263,23 @@ void bar() {
// WIN32: }
}
// We would crash here because the later definition of ForwardDeclare1 results
// in a different IR type for the value we want to store. However, the alloca's
// type will use the argument type selected by fn1.
struct ForwardDeclare1;
typedef void (*FnPtr1)(ForwardDeclare1);
void fn1(FnPtr1, SmallWithDtor) {}
struct ForwardDeclare1 {};
void fn2() { fn1(0, SmallWithDtor()); };
// WIN32-LABEL: define void @"\01?fn2@@YAXXZ"
// WIN32: %[[argmem:[^ ]*]] = alloca inalloca [[argmem_ty:<{ {}\*, %struct.SmallWithDtor }>]]
// WIN32: getelementptr inbounds [[argmem_ty]]* %[[argmem]], i32 0, i32 1
// WIN32: call x86_thiscallcc %struct.SmallWithDtor* @"\01??0SmallWithDtor@@QAE@XZ"(%struct.SmallWithDtor* %0)
// WIN32: getelementptr inbounds [[argmem_ty]]* %[[argmem]], i32 0, i32 0
// WIN32: %[[addr:[^ ]*]] = bitcast {}** %1 to void [[dst_ty:\(%struct.ForwardDeclare1\*\)\*]]*
// WIN32: store void [[dst_ty]] null, void [[dst_ty]]* %[[addr]], align 4
// WIN32: call void @"\01?fn1@@YAXP6AXUForwardDeclare1@@@ZUSmallWithDtor@@@Z"([[argmem_ty]]* inalloca %[[argmem]])