[IRGen] Emit swift_multiPayloadEnumGeneric_destructiveInjectEnumTag

Assign swift_multiPayloadEnumGeneric_destructiveInjectEnumTag as witness function on generic multi payload enums when using layout strings

Author: drexin

lib/IRGen/GenValueWitness.cpp

@@ -936,12 +936,13 @@ getDestructiveInjectEnumTagFunction(IRGenModule &IGM,
                                     const EnumTypeLayoutEntry *typeLayoutEntry,
                                     GenericSignature genericSig) {
   if ((!typeLayoutEntry->layoutString(IGM, genericSig) &&
-       !isRuntimeInstatiatedLayoutString(IGM, typeLayoutEntry)) ||
-      typeLayoutEntry->isSingleton()) {
+       !isRuntimeInstatiatedLayoutString(IGM, typeLayoutEntry))) {
+    return nullptr;
+  } else if (typeLayoutEntry->isSingleton()) {
     return nullptr;
   } else if (!typeLayoutEntry->isFixedSize(IGM)) {
     if (typeLayoutEntry->isMultiPayloadEnum()) {
-      return nullptr;
+      return IGM.getMultiPayloadEnumGenericDestructiveInjectEnumTagFn();
     } else {
       return IGM.getSinglePayloadEnumGenericDestructiveInjectEnumTagFn();
     }

test/Interpreter/layout_string_witnesses_dynamic.swift

@@ -618,6 +618,34 @@ func testResilientSinglePayloadEnumGenericInjectTag() {
 
 testResilientSinglePayloadEnumGenericInjectTag()
 
+@inline(never)
+func matchResilientMultiPayloadEnumGenericTag(_ x: ResilientMultiPayloadEnumGeneric<AnyObject>) -> Int {
+    return switch x {
+    case .nonEmpty0: 0
+    case .nonEmpty1: 1
+    case .empty0: 2
+    case .empty1: 3
+    }
+}
+
+func testResilientMultiPayloadEnumGenericInjectTag() {
+    let x = ResilientMultiPayloadEnumGeneric<AnyObject>.nonEmpty0(SimpleClass(x: 23))
+    let y = ResilientMultiPayloadEnumGeneric<AnyObject>.nonEmpty1(SimpleClass(x: 32))
+    let z = ResilientMultiPayloadEnumGeneric<AnyObject>.empty0
+    let w = ResilientMultiPayloadEnumGeneric<AnyObject>.empty1
+
+    // CHECK: Enum case: 0
+    print("Enum case: \(matchResilientMultiPayloadEnumGenericTag(x))")
+    // CHECK: Enum case: 1
+    print("Enum case: \(matchResilientMultiPayloadEnumGenericTag(y))")
+    // CHECK: Enum case: 2
+    print("Enum case: \(matchResilientMultiPayloadEnumGenericTag(z))")
+    // CHECK: Enum case: 3
+    print("Enum case: \(matchResilientMultiPayloadEnumGenericTag(w))")
+}
+
+testResilientMultiPayloadEnumGenericInjectTag()
+
 #if os(macOS)
 
 import Foundation