[OpenCL] PR43145: preserve addrspace for class accesses

[svenvh]

Summary

PR43145 revealed two places where Clang was attempting to create a
bitcast without considering the address space of class types during
C++ class codegen.

[Anastasia]

LGTM! Thanks!

clang/lib/CodeGen/CGClass.cpp

if (virtualOffset) {
       baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
     }
   } else {
     baseOffset = virtualOffset;
   }
 
   // Apply the base offset.
   llvm::Value *ptr = addr.getPointer();
-  ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy);
+  unsigned AddrSpace = ptr->getType()->getPointerAddressSpace();
+  ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8Ty->getPointerTo(AddrSpace));
   ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr");
 
   // If we have a virtual component, the alignment of the result will
   // be relative only to the known alignment of that vbase.
   CharUnits alignment;
   if (virtualOffset) {
     assert(nearestVBase && "virtual offset without vbase?");
     alignment = CGF.CGM.getVBaseAlignment(addr.getAlignment(),
CodeGenFunction::GetAddressOfDerivedClass(Address BaseAddr,
                                           const CXXRecordDecl *Derived,
                                         CastExpr::path_const_iterator PathBegin,
                                           CastExpr::path_const_iterator PathEnd,
                                           bool NullCheckValue) {
   assert(PathBegin != PathEnd && "Base path should not be empty!");
 
   QualType DerivedTy =
     getContext().getCanonicalType(getContext().getTagDeclType(Derived));
-  llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
+  unsigned AddrSpace =
+    BaseAddr.getPointer()->getType()->getPointerAddressSpace();
+  llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo(AddrSpace);
 
   llvm::Value *NonVirtualOffset =
     CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
 
   if (!NonVirtualOffset) {
     // No offset, we can just cast back.
     return Builder.CreateBitCast(BaseAddr, DerivedPtrTy);
   }

clang/test/CodeGenOpenCLCXX/addrspace-derived-base.cl

 // RUN: %clang_cc1 %s -triple spir -cl-std=clc++ -emit-llvm -O0 -o - | FileCheck %s
 
 struct B {
   int mb;
 };
 
 class D : public B {
 public:
   int getmb() { return mb; }
 };
 
 void foo() {
   D d;
+  //CHECK-LABEL: foo
   //CHECK: addrspacecast %class.D* %d to %class.D addrspace(4)*
   //CHECK: call spir_func i32 @_ZNU3AS41D5getmbEv(%class.D addrspace(4)*
   d.getmb();
 }
 
 //Derived and Base are in the same address space.
 
 //CHECK: define linkonce_odr spir_func i32 @_ZNU3AS41D5getmbEv(%class.D addrspace(4)* %this)
 //CHECK: bitcast %class.D addrspace(4)* %this1 to %struct.B addrspace(4)*
+
+
+// Calling base method through multiple inheritance.
+
+class B2 {
+  public:
+    void baseMethod() const {  }
+    int bb;
+};
+
+class Derived : public B, public B2 {
+  public:
+    void work() const { baseMethod(); }
+    // CHECK-LABEL: work
+    // CHECK: bitcast i8 addrspace(4)* %add.ptr to %class.B2 addrspace(4)*
+};
+
+void pr43145(const Derived *argDerived) {
+  argDerived->work();
+}
+
+// Casting from base to derived.
+
+void pr43145_2(B *argB) {
+  Derived *x = (Derived*)argB;
+}
+
+// CHECK-LABEL: @_Z9pr43145_2
+// CHECK: bitcast %struct.B addrspace(4)* %0 to %class.Derived addrspace(4)*