IRGen: Use the static superclass for virtual dynamic dispatch

Following the self instance pointer to its class metadata isn't sound for chained super calls since it means the same metadata is pulled, resulting infinite recursion. NFC for actual IRGen. SILGen isn't using super_method for native dispatch yet. rdar://problem/22749732
sl2 · Dec 3, 2015 · 58e2b0d · 58e2b0d
1 parent 7dd3046
commit 58e2b0d
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Showing 3 changed files with 23 additions and 23 deletions.
diff --git a/lib/IRGen/GenMeta.cpp b/lib/IRGen/GenMeta.cpp
@@ -4309,18 +4309,22 @@ llvm::Value *irgen::emitVirtualMethodValue(IRGenFunction &IGF,
 
   // Find the metadata.
   llvm::Value *metadata;
-  if ((isa<FuncDecl>(methodDecl) && cast<FuncDecl>(methodDecl)->isStatic()) ||
-      (isa<ConstructorDecl>(methodDecl) &&
-       method.kind == SILDeclRef::Kind::Allocator)) {
-    metadata = base;
-  } else {
-    metadata = emitHeapMetadataRefForHeapObject(IGF, base, baseType,
-                                                /*suppress cast*/ true);
-  }
-
   if (useSuperVTable) {
-    auto superField = emitAddressOfSuperclassRefInClassMetadata(IGF, metadata);
-    metadata = IGF.Builder.CreateLoad(superField);
+    if (auto metaTy = dyn_cast<MetatypeType>(baseType.getSwiftRValueType()))
+      baseType = SILType::getPrimitiveObjectType(metaTy.getInstanceType());
+
+    auto superType = baseType.getSuperclass(/*resolver=*/nullptr);
+    metadata = emitClassHeapMetadataRef(IGF, superType.getSwiftRValueType(),
+                                        MetadataValueType::TypeMetadata);
+  } else {
+    if ((isa<FuncDecl>(methodDecl) && cast<FuncDecl>(methodDecl)->isStatic()) ||
+        (isa<ConstructorDecl>(methodDecl) &&
+         method.kind == SILDeclRef::Kind::Allocator)) {
+      metadata = base;
+    } else {
+      metadata = emitHeapMetadataRefForHeapObject(IGF, base, baseType,
+                                                  /*suppress cast*/ true);
+    }
   }
 
   // Use the type of the method we were type-checked against, not the

diff --git a/test/IRGen/super_class_method.sil b/test/IRGen/super_class_method.sil
@@ -49,10 +49,9 @@ sil_vtable Grandchild {
 }
 
 // CHECK-LABEL: define void @Grandchild_foo(%swift.type*) #0
-// CHECK: [[OPAQUE_GRANDCHILD:%[0-9]+]] = bitcast %swift.type* %0 to %swift.type**
-// CHECK: [[SUPER_METADATA_PTR:%[0-9]+]] = getelementptr inbounds %swift.type*, %swift.type** [[OPAQUE_GRANDCHILD]], i32 1
-// CHECK: [[SUPER_METADATA:%[0-9]+]] = load %swift.type*, %swift.type** [[SUPER_METADATA_PTR]]
-// CHECK: [[FOO_VTABLE_SLOT:%[0-9]+]] = getelementptr inbounds void (%swift.type*)*, void (%swift.type*)**
+// CHECK: [[CHILD_METADATA_PTR:%[0-9]+]] = call %swift.type* @_TMaC18super_class_method5Child()
+// CHECK: [[CASTED_CHILD_METADATA_PTR:%[0-9]+]] = bitcast %swift.type* [[CHILD_METADATA_PTR]] to void (%swift.type*)**
+// CHECK: [[FOO_VTABLE_SLOT:%[0-9]+]] = getelementptr inbounds void (%swift.type*)*, void (%swift.type*)** [[CASTED_CHILD_METADATA_PTR]]
 // CHECK: [[FOO_FNPTR:%[0-9]+]] = load void (%swift.type*)*, void (%swift.type*)** [[FOO_VTABLE_SLOT]]
 // CHECK: call void
 
diff --git a/test/IRGen/super_instance_method.sil b/test/IRGen/super_instance_method.sil
@@ -48,13 +48,10 @@ sil_vtable Grandchild {
   #Parent.foo!1: Grandchild_foo
 }
 
-// CHECK: define void @Grandchild_foo(%C21super_instance_method10Grandchild*)
-// CHECK: [[OPAQUE_GRANDCHILD:%[0-9]+]] = bitcast %C21super_instance_method10Grandchild* %0 to %swift.type**
-// CHECK: [[GRANDCHILD_METADATA:%\..*]] = load %swift.type*, %swift.type** [[OPAQUE_GRANDCHILD]]
-// CHECK: [[OPAQUE_METADATA:%[0-9]+]] = bitcast %swift.type* [[GRANDCHILD_METADATA]] to %swift.type**
-// CHECK: [[SUPER_METADATA_PTR:%[0-9]+]] = getelementptr inbounds %swift.type*, %swift.type** [[OPAQUE_METADATA]], i32 1
-// CHECK: [[SUPER_METADATA:%[0-9]+]] = load %swift.type*, %swift.type** [[SUPER_METADATA_PTR]]
-// CHECK: [[FOO_VTABLE_SLOT:%[0-9]+]] = getelementptr inbounds void (%C21super_instance_method6Parent*)*, void (%C21super_instance_method6Parent*)**
-// CHECK: [[FOO_FNPTR:%[0-9]+]] = load void (%C21super_instance_method6Parent*)*, void (%C21super_instance_method6Parent*)** [[FOO_VTABLE_SLOT]]
+// CHECK-LABEL: define void @Grandchild_foo(%C21super_instance_method10Grandchild*)
+// CHECK: [[CHILD_METADATA_PTR:%[0-9]+]] = call %swift.type* @_TMaC21super_instance_method5Child()
+// CHECK: [[CASTED_CHILD_METADATA_PTR:%[0-9]+]] = bitcast %swift.type* [[CHILD_METADATA_PTR]] to void (%C21super_instance_method6Parent*)**
+// CHECK: [[FOO_VTABLE_SLOT:%[0-9]+]] = getelementptr inbounds void (%C21super_instance_method6Parent*)*, void (%C21super_instance_method6Parent*)** [[CASTED_CHILD_METADATA_PTR]]
+// CHECK: [[FOO_FN_PTR:%[0-9]+]] = load void (%C21super_instance_method6Parent*)*, void (%C21super_instance_method6Parent*)** [[FOO_VTABLE_SLOT]]
 // CHECK: call void