r268418 - [MS] Pass CalleeDecl to adjustThisArgumentForVirtualFunctionCall

[Reid Kleckner via cfe-commits]

Author: rnk
Date: Tue May  3 13:44:29 2016
New Revision: 268418

URL: http://llvm.org/viewvc/llvm-project?rev=268418&view=rev
Log:
[MS] Pass CalleeDecl to adjustThisArgumentForVirtualFunctionCall

If we are devirtualizing, then we want to compute the 'this' adjustment
of the devirtualized target, not the adjustment of the base's method
definition, which is usually zero.

Fixes PR27621

Modified:
    cfe/trunk/lib/CodeGen/CGExprCXX.cpp
    cfe/trunk/test/CodeGenCXX/microsoft-abi-virtual-inheritance.cpp

Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=268418&r1=268417&r2=268418&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Tue May  3 13:44:29 2016
@@ -274,7 +274,7 @@ RValue CodeGenFunction::EmitCXXMemberOrO
 
   if (MD->isVirtual()) {
     This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
-        *this, MD, This, UseVirtualCall);
+        *this, CalleeDecl, This, UseVirtualCall);
   }
 
   return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),

Modified: cfe/trunk/test/CodeGenCXX/microsoft-abi-virtual-inheritance.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/microsoft-abi-virtual-inheritance.cpp?rev=268418&r1=268417&r2=268418&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/microsoft-abi-virtual-inheritance.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/microsoft-abi-virtual-inheritance.cpp Tue May  3 13:44:29 2016
@@ -481,3 +481,21 @@ C::C() : B() {}
 // CHECK:   %[[FIELD:.*]] = getelementptr inbounds i8, i8* %[[B_i8]], i32 4
 // CHECK:   call void @llvm.memset.p0i8.i32(i8* %[[FIELD]], i8 0, i32 4, i32 4, i1 false)
 }
+
+namespace pr27621 {
+// Devirtualization through a static_cast used to make us compute the 'this'
+// adjustment for B::g instead of C::g. When we directly call C::g, 'this' is a
+// B*, and the prologue of C::g will adjust it to a C*.
+struct A { virtual void f(); };
+struct B { virtual void g(); };
+struct C final : A, B {
+  virtual void h();
+  void g() override;
+};
+void callit(C *p) {
+  static_cast<B*>(p)->g();
+}
+// CHECK-LABEL: define void @"\01?callit at pr27621@@YAXPAUC at 1@@Z"(%"struct.pr27621::C"* %{{.*}})
+// CHECK: %[[B_i8:.*]] = getelementptr i8, i8* %1, i32 4
+// CHECK: call x86_thiscallcc void @"\01?g at C@pr27621@@UAEXXZ"(i8* %[[B_i8]])
+}