[CIR] Handle null base class initialization

clang/lib/CIR/CodeGen/CIRGenExpr.cpp

@@ -2134,79 +2134,6 @@ RValue CIRGenFunction::emitCXXMemberCallExpr(const CXXMemberCallExpr *ce,
       ce, md, returnValue, hasQualifier, qualifier, isArrow, base);
 }
 
-void CIRGenFunction::emitCXXConstructExpr(const CXXConstructExpr *e,
-                                          AggValueSlot dest) {
-  assert(!dest.isIgnored() && "Must have a destination!");
-  const CXXConstructorDecl *cd = e->getConstructor();
-
-  // If we require zero initialization before (or instead of) calling the
-  // constructor, as can be the case with a non-user-provided default
-  // constructor, emit the zero initialization now, unless destination is
-  // already zeroed.
-  if (e->requiresZeroInitialization() && !dest.isZeroed()) {
-    switch (e->getConstructionKind()) {
-    case CXXConstructionKind::Delegating:
-    case CXXConstructionKind::Complete:
-      emitNullInitialization(getLoc(e->getSourceRange()), dest.getAddress(),
-                             e->getType());
-      break;
-    case CXXConstructionKind::VirtualBase:
-    case CXXConstructionKind::NonVirtualBase:
-      cgm.errorNYI(e->getSourceRange(),
-                   "emitCXXConstructExpr: base requires initialization");
-      break;
-    }
-  }
-
-  // If this is a call to a trivial default constructor, do nothing.
-  if (cd->isTrivial() && cd->isDefaultConstructor())
-    return;
-
-  // Elide the constructor if we're constructing from a temporary
-  if (getLangOpts().ElideConstructors && e->isElidable()) {
-    // FIXME: This only handles the simplest case, where the source object is
-    //        passed directly as the first argument to the constructor. This
-    //        should also handle stepping through implicit casts and conversion
-    //        sequences which involve two steps, with a conversion operator
-    //        follwed by a converting constructor.
-    const Expr *srcObj = e->getArg(0);
-    assert(srcObj->isTemporaryObject(getContext(), cd->getParent()));
-    assert(
-        getContext().hasSameUnqualifiedType(e->getType(), srcObj->getType()));
-    emitAggExpr(srcObj, dest);
-    return;
-  }
-
-  if (const ArrayType *arrayType = getContext().getAsArrayType(e->getType())) {
-    assert(!cir::MissingFeatures::sanitizers());
-    emitCXXAggrConstructorCall(cd, arrayType, dest.getAddress(), e, false);
-  } else {
-
-    clang::CXXCtorType type = Ctor_Complete;
-    bool forVirtualBase = false;
-    bool delegating = false;
-
-    switch (e->getConstructionKind()) {
-    case CXXConstructionKind::Complete:
-      type = Ctor_Complete;
-      break;
-    case CXXConstructionKind::Delegating:
-      // We should be emitting a constructor; GlobalDecl will assert this
-      type = curGD.getCtorType();
-      delegating = true;
-      break;
-    case CXXConstructionKind::VirtualBase:
-      forVirtualBase = true;
-      [[fallthrough]];
-    case CXXConstructionKind::NonVirtualBase:
-      type = Ctor_Base;
-      break;
-    }
-
-    emitCXXConstructorCall(cd, type, forVirtualBase, delegating, dest, e);
-  }
-}
-
 RValue CIRGenFunction::emitReferenceBindingToExpr(const Expr *e) {
   // Emit the expression as an lvalue.
   LValue lv = emitLValue(e);

clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp

@@ -779,8 +779,8 @@ void AggExprEmitter::visitCXXParenListOrInitListExpr(
     Expr *e, ArrayRef<Expr *> args, FieldDecl *initializedFieldInUnion,
     Expr *arrayFiller) {
 
-  const AggValueSlot dest =
-      ensureSlot(cgf.getLoc(e->getSourceRange()), e->getType());
+  const mlir::Location loc = cgf.getLoc(e->getSourceRange());
+  const AggValueSlot dest = ensureSlot(loc, e->getType());
 
   if (e->getType()->isConstantArrayType()) {
     cir::ArrayType arrayTy =
@@ -819,10 +819,23 @@ void AggExprEmitter::visitCXXParenListOrInitListExpr(
   if (auto *cxxrd = dyn_cast<CXXRecordDecl>(record)) {
     assert(numInitElements >= cxxrd->getNumBases() &&
            "missing initializer for base class");
-    if (cxxrd->getNumBases() > 0) {
-      cgf.cgm.errorNYI(e->getSourceRange(),
-                       "visitCXXParenListOrInitListExpr base class init");
-      return;
+    for (auto &base : cxxrd->bases()) {
+      assert(!base.isVirtual() && "should not see vbases here");
+      CXXRecordDecl *baseRD = base.getType()->getAsCXXRecordDecl();
+      Address address = cgf.getAddressOfDirectBaseInCompleteClass(
+          loc, dest.getAddress(), cxxrd, baseRD,
+          /*baseIsVirtual=*/false);
+      assert(!cir::MissingFeatures::aggValueSlotGC());
+      AggValueSlot aggSlot = AggValueSlot::forAddr(
+          address, Qualifiers(), AggValueSlot::IsDestructed,
+          AggValueSlot::IsNotAliased,
+          cgf.getOverlapForBaseInit(cxxrd, baseRD, false));
+      cgf.emitAggExpr(args[curInitIndex++], aggSlot);
+      if (base.getType().isDestructedType()) {
+        cgf.cgm.errorNYI(e->getSourceRange(),
+                         "push deferred deactivation cleanup");
+        return;
+      }
     }
   }
 

clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp

@@ -234,6 +234,89 @@ RValue CIRGenFunction::emitCXXMemberOrOperatorCall(
   return emitCall(fnInfo, callee, returnValue, args, nullptr, loc);
 }
 
+static void emitNullBaseClassInitialization(CIRGenFunction &cgf,
+                                            Address destPtr,
+                                            const CXXRecordDecl *base) {
+  if (base->isEmpty())
+    return;
+
+  cgf.cgm.errorNYI(base->getSourceRange(),
+                   "emitNullBaseClassInitialization: not empty");
+}
+
+void CIRGenFunction::emitCXXConstructExpr(const CXXConstructExpr *e,
+                                          AggValueSlot dest) {
+  assert(!dest.isIgnored() && "Must have a destination!");
+  const CXXConstructorDecl *cd = e->getConstructor();
+
+  // If we require zero initialization before (or instead of) calling the
+  // constructor, as can be the case with a non-user-provided default
+  // constructor, emit the zero initialization now, unless destination is
+  // already zeroed.
+  if (e->requiresZeroInitialization() && !dest.isZeroed()) {
+    switch (e->getConstructionKind()) {
+    case CXXConstructionKind::Delegating:
+    case CXXConstructionKind::Complete:
+      emitNullInitialization(getLoc(e->getSourceRange()), dest.getAddress(),
+                             e->getType());
+      break;
+    case CXXConstructionKind::VirtualBase:
+    case CXXConstructionKind::NonVirtualBase:
+      emitNullBaseClassInitialization(*this, dest.getAddress(),
+                                      cd->getParent());
+      break;
+    }
+  }
+
+  // If this is a call to a trivial default constructor, do nothing.
+  if (cd->isTrivial() && cd->isDefaultConstructor())
+    return;
+
+  // Elide the constructor if we're constructing from a temporary
+  if (getLangOpts().ElideConstructors && e->isElidable()) {
+    // FIXME: This only handles the simplest case, where the source object is
+    //        passed directly as the first argument to the constructor. This
+    //        should also handle stepping through implicit casts and conversion
+    //        sequences which involve two steps, with a conversion operator
+    //        follwed by a converting constructor.
+    const Expr *srcObj = e->getArg(0);
+    assert(srcObj->isTemporaryObject(getContext(), cd->getParent()));
+    assert(
+        getContext().hasSameUnqualifiedType(e->getType(), srcObj->getType()));
+    emitAggExpr(srcObj, dest);
+    return;
+  }
+
+  if (const ArrayType *arrayType = getContext().getAsArrayType(e->getType())) {
+    assert(!cir::MissingFeatures::sanitizers());
+    emitCXXAggrConstructorCall(cd, arrayType, dest.getAddress(), e, false);
+  } else {
+
+    clang::CXXCtorType type = Ctor_Complete;
+    bool forVirtualBase = false;
+    bool delegating = false;
+
+    switch (e->getConstructionKind()) {
+    case CXXConstructionKind::Complete:
+      type = Ctor_Complete;
+      break;
+    case CXXConstructionKind::Delegating:
+      // We should be emitting a constructor; GlobalDecl will assert this
+      type = curGD.getCtorType();
+      delegating = true;
+      break;
+    case CXXConstructionKind::VirtualBase:
+      forVirtualBase = true;
+      [[fallthrough]];
+    case CXXConstructionKind::NonVirtualBase:
+      type = Ctor_Base;
+      break;
+    }
+
+    emitCXXConstructorCall(cd, type, forVirtualBase, delegating, dest, e);
+  }
+}
+
 static CharUnits calculateCookiePadding(CIRGenFunction &cgf,
                                         const CXXNewExpr *e) {
   if (!e->isArray())

clang/test/CIR/CodeGen/ctor-null-init.cpp

@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir --check-prefix=CIR %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll --check-prefix=LLVM %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll --check-prefix=OGCG %s
+
+struct A {
+  A() = default;
+  A(int); // This constructor triggers the null base class initialization.
+};
+
+struct B : A {
+};
+
+void test_empty_base_null_init() {
+  B{};
+}
+
+// CIR: cir.func {{.*}} @_Z25test_empty_base_null_initv()
+// CIR-NEXT:   %[[B_ADDR:.*]] = cir.alloca !rec_B, !cir.ptr<!rec_B>, ["agg.tmp.ensured"]
+// CIR-NEXT:   %[[A_ADDR:.*]] = cir.base_class_addr %[[B_ADDR]] : !cir.ptr<!rec_B> nonnull [0] -> !cir.ptr<!rec_A>
+
+// LLVM: define{{.*}} @_Z25test_empty_base_null_initv()
+// LLVM-NEXT:   %[[B:.*]] = alloca %struct.B
+// LLVM-NEXT:   ret void
+
+// OGCG: define{{.*}} @_Z25test_empty_base_null_initv()
+// OGCG-NEXT: entry:
+// OGCG-NEXT:   %[[B:.*]] = alloca %struct.B
+// OGCG-NEXT:   ret void