MS ABI: Use the correct this arg when generating implict copy ctor
We assumed that the incoming this argument would be the last argument.
However, this is not true under the MS ABI.
This fixes PR20897.
llvm-svn: 217642
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 173099a..04b7ea0 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -50,6 +50,18 @@
bool isSRetParameterAfterThis() const override { return true; }
+ size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
+ FunctionArgList &Args) const override {
+ assert(Args.size() >= 2 &&
+ "expected the arglist to have at least two args!");
+ // The 'most_derived' parameter goes second if the ctor is variadic and
+ // has v-bases.
+ if (CD->getParent()->getNumVBases() > 0 &&
+ CD->getType()->castAs<FunctionProtoType>()->isVariadic())
+ return 2;
+ return 1;
+ }
+
StringRef GetPureVirtualCallName() override { return "_purecall"; }
// No known support for deleted functions in MSVC yet, so this choice is
// arbitrary.