Author: lattner
Date: Mon Aug 23 00:26:13 2010
New Revision: 111794
URL: http://llvm.org/viewvc/llvm-project?rev=111794&view=rev
Log:
fix rdar://8340348, a miscompile of boost that was exposed by r109848.
That revision started classifying truly empty structs like "Y" and "X"
as being NoClass/NoClass and turning them into 'ignore'. The call code
turns around and allocates space for the ignored argument with
GetUndefRValue. The bug is that GetUndefRValue would return the address
as undef, instead of returning an object with a defined address but
undefined contents.
Modified:
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/test/CodeGenCXX/x86_64-arguments.cpp
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=111794&r1=111793&r2=111794&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Mon Aug 23 00:26:13 2010
@@ -441,9 +441,12 @@
return RValue::getComplex(std::make_pair(U, U));
}
+ // If this is a use of an undefined aggregate type, the aggregate must have
an
+ // identifiable address. Just because the contents of the value are
undefined
+ // doesn't mean that the address can't be taken and compared.
if (hasAggregateLLVMType(Ty)) {
- const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
- return RValue::getAggregate(llvm::UndefValue::get(LTy));
+ llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
+ return RValue::getAggregate(DestPtr);
}
return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
Modified: cfe/trunk/test/CodeGenCXX/x86_64-arguments.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/x86_64-arguments.cpp?rev=111794&r1=111793&r2=111794&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/x86_64-arguments.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/x86_64-arguments.cpp Mon Aug 23 00:26:13 2010
@@ -76,3 +76,27 @@
return b2.b1.pa;
}
}
+
+namespace test5 {
+ struct Xbase { };
+ struct Empty { };
+ struct Y;
+ struct X : public Xbase {
+ Empty empty;
+ Y f();
+ };
+ struct Y : public X {
+ Empty empty;
+ };
+ X getX();
+ int takeY(const Y&, int y);
+ void g() {
+ // rdar://8340348 - The temporary for the X object needs to have a defined
+ // address when passed into X::f as 'this'.
+ takeY(getX().f(), 42);
+ }
+ // CHECK: void @_ZN5test51gEv()
+ // CHECK: alloca %"struct.test5::Y"
+ // CHECK: alloca %"struct.test5::X"
+ // CHECK: alloca %"struct.test5::Y"
+}
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