[CIR] Call base class destructors (#162562)

This adds handling for calling virtual and non-virtual base class
destructors. Non-virtual base class destructors are call from the base
(D2) destructor body for derived classes. Virtual base class destructors
are called only from the complete (D1) destructor.

Author: andykaylor

clang/lib/CIR/CodeGen/CIRGenCXXABI.h

@@ -155,6 +155,14 @@ class CIRGenCXXABI {
   /// Loads the incoming C++ this pointer as it was passed by the caller.
   mlir::Value loadIncomingCXXThis(CIRGenFunction &cgf);
 
+  /// Get the implicit (second) parameter that comes after the "this" pointer,
+  /// or nullptr if there is isn't one.
+  virtual mlir::Value getCXXDestructorImplicitParam(CIRGenFunction &cgf,
+                                                    const CXXDestructorDecl *dd,
+                                                    CXXDtorType type,
+                                                    bool forVirtualBase,
+                                                    bool delegating) = 0;
+
   /// Emit constructor variants required by this ABI.
   virtual void emitCXXConstructors(const clang::CXXConstructorDecl *d) = 0;
 

clang/lib/CIR/CodeGen/CIRGenClass.cpp

@@ -126,6 +126,30 @@ static bool isInitializerOfDynamicClass(const CXXCtorInitializer *baseInit) {
 }
 
 namespace {
+/// Call the destructor for a direct base class.
+struct CallBaseDtor final : EHScopeStack::Cleanup {
+  const CXXRecordDecl *baseClass;
+  bool baseIsVirtual;
+  CallBaseDtor(const CXXRecordDecl *base, bool baseIsVirtual)
+      : baseClass(base), baseIsVirtual(baseIsVirtual) {}
+
+  void emit(CIRGenFunction &cgf) override {
+    const CXXRecordDecl *derivedClass =
+        cast<CXXMethodDecl>(cgf.curFuncDecl)->getParent();
+
+    const CXXDestructorDecl *d = baseClass->getDestructor();
+    // We are already inside a destructor, so presumably the object being
+    // destroyed should have the expected type.
+    QualType thisTy = d->getFunctionObjectParameterType();
+    assert(cgf.currSrcLoc && "expected source location");
+    Address addr = cgf.getAddressOfDirectBaseInCompleteClass(
+        *cgf.currSrcLoc, cgf.loadCXXThisAddress(), derivedClass, baseClass,
+        baseIsVirtual);
+    cgf.emitCXXDestructorCall(d, Dtor_Base, baseIsVirtual,
+                              /*delegating=*/false, addr, thisTy);
+  }
+};
+
 /// A visitor which checks whether an initializer uses 'this' in a
 /// way which requires the vtable to be properly set.
 struct DynamicThisUseChecker
@@ -922,8 +946,21 @@ void CIRGenFunction::enterDtorCleanups(const CXXDestructorDecl *dd,
   if (dtorType == Dtor_Complete) {
     assert(!cir::MissingFeatures::sanitizers());
 
-    if (classDecl->getNumVBases())
-      cgm.errorNYI(dd->getSourceRange(), "virtual base destructor cleanups");
+    // We push them in the forward order so that they'll be popped in
+    // the reverse order.
+    for (const CXXBaseSpecifier &base : classDecl->vbases()) {
+      auto *baseClassDecl = base.getType()->castAsCXXRecordDecl();
+
+      if (baseClassDecl->hasTrivialDestructor()) {
+        // Under SanitizeMemoryUseAfterDtor, poison the trivial base class
+        // memory. For non-trival base classes the same is done in the class
+        // destructor.
+        assert(!cir::MissingFeatures::sanitizers());
+      } else {
+        ehStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup, baseClassDecl,
+                                          /*baseIsVirtual=*/true);
+      }
+    }
 
     return;
   }
@@ -942,8 +979,8 @@ void CIRGenFunction::enterDtorCleanups(const CXXDestructorDecl *dd,
     if (baseClassDecl->hasTrivialDestructor())
       assert(!cir::MissingFeatures::sanitizers());
     else
-      cgm.errorNYI(dd->getSourceRange(),
-                   "non-trivial base destructor cleanups");
+      ehStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup, baseClassDecl,
+                                        /*baseIsVirtual=*/false);
   }
 
   assert(!cir::MissingFeatures::sanitizers());

clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp

@@ -59,7 +59,11 @@ class CIRGenItaniumCXXABI : public CIRGenCXXABI {
 
   void addImplicitStructorParams(CIRGenFunction &cgf, QualType &resTy,
                                  FunctionArgList &params) override;
-
+  mlir::Value getCXXDestructorImplicitParam(CIRGenFunction &cgf,
+                                            const CXXDestructorDecl *dd,
+                                            CXXDtorType type,
+                                            bool forVirtualBase,
+                                            bool delegating) override;
   void emitCXXConstructors(const clang::CXXConstructorDecl *d) override;
   void emitCXXDestructors(const clang::CXXDestructorDecl *d) override;
   void emitCXXStructor(clang::GlobalDecl gd) override;
@@ -1504,11 +1508,8 @@ void CIRGenItaniumCXXABI::emitDestructorCall(
     CIRGenFunction &cgf, const CXXDestructorDecl *dd, CXXDtorType type,
     bool forVirtualBase, bool delegating, Address thisAddr, QualType thisTy) {
   GlobalDecl gd(dd, type);
-  if (needsVTTParameter(gd)) {
-    cgm.errorNYI(dd->getSourceRange(), "emitDestructorCall: VTT");
-  }
-
-  mlir::Value vtt = nullptr;
+  mlir::Value vtt =
+      getCXXDestructorImplicitParam(cgf, dd, type, forVirtualBase, delegating);
   ASTContext &astContext = cgm.getASTContext();
   QualType vttTy = astContext.getPointerType(astContext.VoidPtrTy);
   assert(!cir::MissingFeatures::appleKext());
@@ -1540,6 +1541,13 @@ void CIRGenItaniumCXXABI::registerGlobalDtor(const VarDecl *vd,
   // prepare. Nothing to be done for CIR here.
 }
 
+mlir::Value CIRGenItaniumCXXABI::getCXXDestructorImplicitParam(
+    CIRGenFunction &cgf, const CXXDestructorDecl *dd, CXXDtorType type,
+    bool forVirtualBase, bool delegating) {
+  GlobalDecl gd(dd, type);
+  return cgf.getVTTParameter(gd, forVirtualBase, delegating);
+}
+
 // The idea here is creating a separate block for the throw with an
 // `UnreachableOp` as the terminator. So, we branch from the current block
 // to the throw block and create a block for the remaining operations.

clang/test/CIR/CodeGen/dtors.cpp

@@ -208,3 +208,84 @@ void test_nested_dtor() {
 // OGCG: define {{.*}} void @_ZN1DD2Ev
 // OGCG:   %[[C:.*]] = getelementptr inbounds i8, ptr %{{.*}}, i64 4
 // OGCG:   call void @_ZN1CD1Ev(ptr {{.*}} %[[C]])
+
+struct E {
+  ~E();
+};
+
+struct F : public E {
+  int n;
+  ~F() {}
+};
+
+// CIR: cir.func {{.*}} @_ZN1FD2Ev
+// CIR:   %[[BASE_E:.*]] = cir.base_class_addr %{{.*}} : !cir.ptr<!rec_F> nonnull [0] -> !cir.ptr<!rec_E>
+// CIR:   cir.call @_ZN1ED2Ev(%[[BASE_E]]) nothrow : (!cir.ptr<!rec_E>) -> ()
+
+// Because E is at offset 0 in F, there is no getelementptr needed.
+
+// LLVM: define {{.*}} void @_ZN1FD2Ev
+// LLVM:   call void @_ZN1ED2Ev(ptr %{{.*}})
+
+// This destructor is defined after the calling function in OGCG.
+
+void test_base_dtor_call() {
+  F f;
+}
+
+// CIR: cir.func {{.*}} @_Z19test_base_dtor_callv()
+//   cir.call @_ZN1FD2Ev(%{{.*}}) nothrow : (!cir.ptr<!rec_F>) -> ()
+
+// LLVM: define {{.*}} void @_Z19test_base_dtor_callv()
+// LLVM:   call void @_ZN1FD2Ev(ptr %{{.*}})
+
+// OGCG: define {{.*}} void @_Z19test_base_dtor_callv()
+// OGCG:   call void @_ZN1FD2Ev(ptr {{.*}} %{{.*}})
+
+// OGCG: define {{.*}} void @_ZN1FD2Ev
+// OGCG:   call void @_ZN1ED2Ev(ptr {{.*}} %{{.*}})
+
+struct VirtualBase {
+  ~VirtualBase();
+};
+
+struct Derived : virtual VirtualBase {
+  ~Derived() {}
+};
+
+void test_base_dtor_call_virtual_base() {
+  Derived d;
+}
+
+// Derived D2 (base) destructor -- does not call VirtualBase destructor
+
+// CIR:     cir.func {{.*}} @_ZN7DerivedD2Ev
+// CIR-NOT:   cir.call{{.*}} @_ZN11VirtualBaseD2Ev
+// CIR:       cir.return
+
+// LLVM:     define {{.*}} void @_ZN7DerivedD2Ev
+// LLVM-NOT:   call{{.*}} @_ZN11VirtualBaseD2Ev
+// LLVM:       ret
+
+// Derived D1 (complete) destructor -- does call VirtualBase destructor
+
+// CIR: cir.func {{.*}} @_ZN7DerivedD1Ev
+// CIR:   %[[THIS:.*]] = cir.load %{{.*}}
+// CIR:   %[[VTT:.*]] = cir.vtt.address_point @_ZTT7Derived, offset = 0 -> !cir.ptr<!cir.ptr<!void>>
+// CIR:   cir.call @_ZN7DerivedD2Ev(%[[THIS]], %[[VTT]])
+// CIR:   %[[VIRTUAL_BASE:.*]] = cir.base_class_addr %[[THIS]] : !cir.ptr<!rec_Derived> nonnull [0] -> !cir.ptr<!rec_VirtualBase>
+// CIR:   cir.call @_ZN11VirtualBaseD2Ev(%[[VIRTUAL_BASE]])
+
+// LLVM: define {{.*}} void @_ZN7DerivedD1Ev
+// LLVM:   call void @_ZN7DerivedD2Ev(ptr %{{.*}}, ptr @_ZTT7Derived)
+// LLVM:   call void @_ZN11VirtualBaseD2Ev(ptr %{{.*}})
+
+// OGCG emits these destructors in reverse order
+
+// OGCG: define {{.*}} void @_ZN7DerivedD1Ev
+// OGCG:   call void @_ZN7DerivedD2Ev(ptr {{.*}} %{{.*}}, ptr {{.*}} @_ZTT7Derived)
+// OGCG:   call void @_ZN11VirtualBaseD2Ev(ptr {{.*}} %{{.*}})
+
+// OGCG:     define {{.*}} void @_ZN7DerivedD2Ev
+// OGCG-NOT:   call{{.*}} @_ZN11VirtualBaseD2Ev
+// OGCG:       ret