[Runtime+IRGen] Fix existential offset for multiple protocol witnesses

Author: drexin

lib/IRGen/TypeLayout.cpp

@@ -364,7 +364,7 @@ class LayoutStringBuilder {
         uint64_t op = (static_cast<uint64_t>(refCounting.kind) << 56) | skip;
         B.addInt64(op);
         refCountBytes += sizeof(uint64_t);
-        skip = 0;
+        skip = refCounting.size - getFixedBufferSize(IGM).getValue();
         break;
       }
 

stdlib/public/runtime/BytecodeLayouts.cpp

@@ -684,7 +684,7 @@ static void existentialDestroyBranchless(const Metadata *metadata,
                                uint8_t *addr) {
   OpaqueValue *object = (OpaqueValue *)(addr + addrOffset);
   auto* type = getExistentialTypeMetadata(object);
-  addrOffset += sizeof(uintptr_t) * (NumWords_ValueBuffer + 2);
+  addrOffset += sizeof(uintptr_t) * NumWords_ValueBuffer;
   if (type->getValueWitnesses()->isValueInline()) {
     type->vw_destroy(object);
   } else {
@@ -918,12 +918,9 @@ static void existentialInitWithCopyBranchless(const Metadata *metadata,
                                uint8_t *src) {
   uintptr_t _addrOffset = addrOffset;
   auto *type = getExistentialTypeMetadata((OpaqueValue*)(src + _addrOffset));
-  auto *witness = *(void**)(src + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)));
-  memcpy(dest + _addrOffset + (NumWords_ValueBuffer * sizeof(uintptr_t)), &type, sizeof(uintptr_t));
-  memcpy(dest + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)), &witness, sizeof(uintptr_t));
   auto *destObject = (ValueBuffer *)(dest + _addrOffset);
   auto *srcObject = (ValueBuffer *)(src + _addrOffset);
-  addrOffset = _addrOffset + (sizeof(uintptr_t) * (2 + NumWords_ValueBuffer));
+  addrOffset = _addrOffset + (sizeof(uintptr_t) * NumWords_ValueBuffer);
   type->vw_initializeBufferWithCopyOfBuffer(destObject, srcObject);
 }
 
@@ -1062,12 +1059,9 @@ static void existentialInitWithTake(const Metadata *metadata,
                                uint8_t *src) {
   uintptr_t _addrOffset = addrOffset;
   auto* type = getExistentialTypeMetadata((OpaqueValue*)(src + addrOffset));
-  auto *witness = *(void**)(src + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)));
   auto *destObject = (OpaqueValue *)(dest + _addrOffset);
   auto *srcObject = (OpaqueValue *)(src + _addrOffset);
-  memcpy(dest + _addrOffset + (NumWords_ValueBuffer * sizeof(uintptr_t)), &type, sizeof(uintptr_t));
-  memcpy(dest + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)), &witness, sizeof(uintptr_t));
-  addrOffset = _addrOffset + (sizeof(uintptr_t) * (2 + NumWords_ValueBuffer));
+  addrOffset = _addrOffset + (sizeof(uintptr_t) * NumWords_ValueBuffer);
   if (SWIFT_UNLIKELY(!type->getValueWitnesses()->isBitwiseTakable())) {
     type->vw_initializeWithTake(destObject, srcObject);
   }
@@ -1317,12 +1311,9 @@ static void existentialAssignWithCopy(const Metadata *metadata,
                                uint8_t *src) {
   uintptr_t _addrOffset = addrOffset;
   auto *type = getExistentialTypeMetadata((OpaqueValue*)(src + _addrOffset));
-  auto *witness = *(void**)(src + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)));
-  memcpy(dest + _addrOffset + (NumWords_ValueBuffer * sizeof(uintptr_t)), &type, sizeof(uintptr_t));
-  memcpy(dest + _addrOffset + ((NumWords_ValueBuffer + 1) * sizeof(uintptr_t)), &witness, sizeof(uintptr_t));
   auto *destObject = (OpaqueValue *)(dest + _addrOffset);
   auto *srcObject = (OpaqueValue *)(src + _addrOffset);
-  addrOffset = _addrOffset + (sizeof(uintptr_t) * (2 + NumWords_ValueBuffer));
+  addrOffset = _addrOffset + (sizeof(uintptr_t) * NumWords_ValueBuffer);
   if (type->getValueWitnesses()->isValueInline()) {
     type->vw_assignWithCopy(destObject, srcObject);
   } else {

test/Interpreter/Inputs/layout_string_witnesses_types.swift

@@ -264,6 +264,21 @@ public enum Repro {
     }
 }
 
+public protocol A {}
+public protocol B {}
+public protocol C {}
+
+public struct MultiProtocolExistentialWrapper {
+    let x: Int = 0
+    let y: any (A&B&C)
+    let z: AnyObject
+
+    public init(y: any (A&B&C), z: AnyObject) {
+        self.y = y
+        self.z = z
+    }
+}
+
 #if os(macOS)
 import Foundation
 

test/Interpreter/layout_string_witnesses_static.swift

@@ -293,6 +293,43 @@ func testExistentialStructBox() {
 
 testExistentialStructBox()
 
+class ClassWithABC: A, B, C {
+    deinit {
+        print("ClassWithABC deinitialized!")
+    }
+}
+
+func testMultiProtocolExistential() {
+    let ptr = UnsafeMutablePointer<MultiProtocolExistentialWrapper>.allocate(capacity: 1)
+
+    do {
+        let x = ClassWithABC()
+        testInit(ptr, to: MultiProtocolExistentialWrapper(y: x, z: SimpleClass(x: 23)))
+    }
+
+    do {
+        let y = ClassWithABC()
+
+        // CHECK: Before deinit
+        print("Before deinit")
+
+        // CHECK-NEXT: ClassWithABC deinitialized!
+        // CHECK-NEXT: SimpleClass deinitialized!
+        testAssign(ptr, from: MultiProtocolExistentialWrapper(y: y, z: SimpleClass(x: 32)))
+    }
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+    // CHECK-NEXT: ClassWithABC deinitialized!
+    // CHECK-NEXT: SimpleClass deinitialized!
+    testDestroy(ptr)
+
+    ptr.deallocate()
+}
+
+testMultiProtocolExistential()
+
 class ClassWithSomeClassProtocol: SomeClassProtocol {
     deinit {
         print("ClassWithSomeClassProtocol deinitialized!")