Sema: Do not assert when dereferencing member pointer using virtual inheritance with an incomplete class type

The MS ABI requires that we determine the vbptr offset if have a
virtual inheritance model.  Instead, raise an error pointing to the
diagnostic when this happens.

This fixes PR18583.

Differential Revision: http://llvm-reviews.chandlerc.com/D2842

llvm-svn: 201824

clang/lib/CodeGen/CGCXXABI.cpp

@@ -37,10 +37,9 @@ CGCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
   return CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
 }
 
-llvm::Value *CGCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
-                                                       llvm::Value *&This,
-                                                       llvm::Value *MemPtr,
-                                                 const MemberPointerType *MPT) {
+llvm::Value *CGCXXABI::EmitLoadOfMemberFunctionPointer(
+    CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
+    llvm::Value *MemPtr, const MemberPointerType *MPT) {
   ErrorUnsupportedABI(CGF, "calls through member pointers");
 
   const FunctionProtoType *FPT = 
@@ -52,10 +51,10 @@ llvm::Value *CGCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
   return llvm::Constant::getNullValue(FTy->getPointerTo());
 }
 
-llvm::Value *CGCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
-                                                    llvm::Value *Base,
-                                                    llvm::Value *MemPtr,
-                                              const MemberPointerType *MPT) {
+llvm::Value *
+CGCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
+                                       llvm::Value *Base, llvm::Value *MemPtr,
+                                       const MemberPointerType *MPT) {
   ErrorUnsupportedABI(CGF, "loads of member pointers");
   llvm::Type *Ty = CGF.ConvertType(MPT->getPointeeType())->getPointerTo();
   return llvm::Constant::getNullValue(Ty);

clang/lib/CodeGen/CGCXXABI.h

@@ -122,17 +122,15 @@ public:
   /// Load a member function from an object and a member function
   /// pointer.  Apply the this-adjustment and set 'This' to the
   /// adjusted value.
-  virtual llvm::Value *
-  EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
-                                  llvm::Value *&This,
-                                  llvm::Value *MemPtr,
-                                  const MemberPointerType *MPT);
+  virtual llvm::Value *EmitLoadOfMemberFunctionPointer(
+      CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
+      llvm::Value *MemPtr, const MemberPointerType *MPT);
 
   /// Calculate an l-value from an object and a data member pointer.
-  virtual llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
-                                                    llvm::Value *Base,
-                                                    llvm::Value *MemPtr,
-                                            const MemberPointerType *MPT);
+  virtual llvm::Value *
+  EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
+                               llvm::Value *Base, llvm::Value *MemPtr,
+                               const MemberPointerType *MPT);
 
   /// Perform a derived-to-base, base-to-derived, or bitcast member
   /// pointer conversion.

clang/lib/CodeGen/CGExpr.cpp

@@ -390,7 +390,7 @@ LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
     case SubobjectAdjustment::MemberPointerAdjustment: {
       llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
       Object = CGM.getCXXABI().EmitMemberDataPointerAddress(
-                    *this, Object, Ptr, Adjustment.Ptr.MPT);
+          *this, E, Object, Ptr, Adjustment.Ptr.MPT);
       break;
     }
     }
@@ -3239,8 +3239,8 @@ EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
   const MemberPointerType *MPT
     = E->getRHS()->getType()->getAs<MemberPointerType>();
 
-  llvm::Value *AddV =
-    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
+  llvm::Value *AddV = CGM.getCXXABI().EmitMemberDataPointerAddress(
+      *this, E, BaseV, OffsetV, MPT);
 
   return MakeAddrLValue(AddV, MPT->getPointeeType());
 }

clang/lib/CodeGen/CGExprCXX.cpp

@@ -260,7 +260,7 @@ CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
 
   // Ask the ABI to load the callee.  Note that This is modified.
   llvm::Value *Callee =
-    CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, This, MemFnPtr, MPT);
+    CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT);
   
   CallArgList Args;
 

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -71,11 +71,12 @@ public:
   llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT);
 
   llvm::Value *EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
+                                               const Expr *E,
                                                llvm::Value *&This,
                                                llvm::Value *MemFnPtr,
                                                const MemberPointerType *MPT);
 
-  llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
+  llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
                                             llvm::Value *Base,
                                             llvm::Value *MemPtr,
                                             const MemberPointerType *MPT);
@@ -300,11 +301,9 @@ ItaniumCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
 ///
 /// If the member is non-virtual, memptr.ptr is the address of
 /// the function to call.
-llvm::Value *
-ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
-                                               llvm::Value *&This,
-                                               llvm::Value *MemFnPtr,
-                                               const MemberPointerType *MPT) {
+llvm::Value *ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
+    CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
+    llvm::Value *MemFnPtr, const MemberPointerType *MPT) {
   CGBuilderTy &Builder = CGF.Builder;
 
   const FunctionProtoType *FPT = 
@@ -386,10 +385,9 @@ ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
 
 /// Compute an l-value by applying the given pointer-to-member to a
 /// base object.
-llvm::Value *ItaniumCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
-                                                         llvm::Value *Base,
-                                                         llvm::Value *MemPtr,
-                                           const MemberPointerType *MPT) {
+llvm::Value *ItaniumCXXABI::EmitMemberDataPointerAddress(
+    CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
+    const MemberPointerType *MPT) {
   assert(MemPtr->getType() == CGM.PtrDiffTy);
 
   CGBuilderTy &Builder = CGF.Builder;

clang/lib/CodeGen/MicrosoftCXXABI.cpp

@@ -302,8 +302,8 @@ private:
 
   /// \brief Performs a full virtual base adjustment.  Used to dereference
   /// pointers to members of virtual bases.
-  llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const CXXRecordDecl *RD,
-                                 llvm::Value *Base,
+  llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
+                                 const CXXRecordDecl *RD, llvm::Value *Base,
                                  llvm::Value *VirtualBaseAdjustmentOffset,
                                  llvm::Value *VBPtrOffset /* optional */);
 
@@ -353,10 +353,10 @@ public:
                                                   llvm::Value *MemPtr,
                                                   const MemberPointerType *MPT);
 
-  virtual llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
-                                                    llvm::Value *Base,
-                                                    llvm::Value *MemPtr,
-                                                  const MemberPointerType *MPT);
+  virtual llvm::Value *
+  EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
+                               llvm::Value *Base, llvm::Value *MemPtr,
+                               const MemberPointerType *MPT);
 
   virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
                                                    const CastExpr *E,
@@ -366,9 +366,8 @@ public:
                                                       llvm::Constant *Src);
 
   virtual llvm::Value *
-  EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
-                                  llvm::Value *&This,
-                                  llvm::Value *MemPtr,
+  EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
+                                  llvm::Value *&This, llvm::Value *MemPtr,
                                   const MemberPointerType *MPT);
 
 private:
@@ -1687,11 +1686,9 @@ MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
 
 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
 // it.
-llvm::Value *
-MicrosoftCXXABI::AdjustVirtualBase(CodeGenFunction &CGF,
-                                   const CXXRecordDecl *RD, llvm::Value *Base,
-                                   llvm::Value *VBTableOffset,
-                                   llvm::Value *VBPtrOffset) {
+llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
+    CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
+    llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
   CGBuilderTy &Builder = CGF.Builder;
   Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
   llvm::BasicBlock *OriginalBB = 0;
@@ -1717,7 +1714,14 @@ MicrosoftCXXABI::AdjustVirtualBase(CodeGenFunction &CGF,
   // know the vbptr offset.
   if (!VBPtrOffset) {
     CharUnits offs = CharUnits::Zero();
-    if (RD->getNumVBases())
+    if (!RD->hasDefinition()) {
+      DiagnosticsEngine &Diags = CGF.CGM.getDiags();
+      unsigned DiagID = Diags.getCustomDiagID(
+          DiagnosticsEngine::Error,
+          "member pointer representation requires a "
+          "complete class type for %0 to perform this expression");
+      Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
+    } else if (RD->getNumVBases())
       offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
     VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
   }
@@ -1738,11 +1742,9 @@ MicrosoftCXXABI::AdjustVirtualBase(CodeGenFunction &CGF,
   return AdjustedBase;
 }
 
-llvm::Value *
-MicrosoftCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
-                                              llvm::Value *Base,
-                                              llvm::Value *MemPtr,
-                                              const MemberPointerType *MPT) {
+llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
+    CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
+    const MemberPointerType *MPT) {
   assert(MPT->isMemberDataPointer());
   unsigned AS = Base->getType()->getPointerAddressSpace();
   llvm::Type *PType =
@@ -1767,7 +1769,7 @@ MicrosoftCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
   }
 
   if (VirtualBaseAdjustmentOffset) {
-    Base = AdjustVirtualBase(CGF, RD, Base, VirtualBaseAdjustmentOffset,
+    Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
                              VBPtrOffset);
   }
 
@@ -1975,11 +1977,9 @@ MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
   return llvm::ConstantStruct::getAnon(Fields);
 }
 
-llvm::Value *
-MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
-                                                 llvm::Value *&This,
-                                                 llvm::Value *MemPtr,
-                                                 const MemberPointerType *MPT) {
+llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
+    CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
+    llvm::Value *MemPtr, const MemberPointerType *MPT) {
   assert(MPT->isMemberFunctionPointer());
   const FunctionProtoType *FPT =
     MPT->getPointeeType()->castAs<FunctionProtoType>();
@@ -2010,7 +2010,7 @@ MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
   }
 
   if (VirtualBaseAdjustmentOffset) {
-    This = AdjustVirtualBase(CGF, RD, This, VirtualBaseAdjustmentOffset,
+    This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
                              VBPtrOffset);
   }
 

clang/test/CodeGenCXX/microsoft-abi-member-pointers.cpp

@@ -1,7 +1,10 @@
 // RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -triple=i386-pc-win32 | FileCheck %s
+// RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -triple=i386-pc-win32 -DINCOMPLETE_VIRTUAL -fms-extensions -verify
+// RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -triple=i386-pc-win32 -DINCOMPLETE_VIRTUAL -DMEMFUN -fms-extensions -verify
 // FIXME: Test x86_64 member pointers when codegen no longer asserts on records
 // with virtual bases.
 
+#ifndef INCOMPLETE_VIRTUAL
 struct B1 {
   void foo();
   int b;
@@ -557,3 +560,15 @@ int *load_data(A *a, int A::*mp) {
 }
 
 }
+#else
+struct __virtual_inheritance A;
+#ifdef MEMFUN
+int foo(A *a, int (A::*mp)()) {
+    return (a->*mp)(); // expected-error{{requires a complete class type}}
+}
+#else
+int foo(A *a, int A::*mp) {
+    return a->*mp; // expected-error{{requires a complete class type}}
+}
+#endif
+#endif