Merge pull request #67173 from drexin/wip-singleton-inject

Support destructiveInjectEnumTag in singleton enums with layout strings

Author: drexin

include/swift/Runtime/RuntimeFunctions.def

@@ -2336,6 +2336,17 @@ FUNCTION(SingletonEnumGetEnumTag,
          ATTRS(NoUnwind, WillReturn),
          EFFECT(NoEffect))
 
+// void swift_singletonEnum_destructiveInjectEnumTag(swift::OpaqueValue *address,
+//                                                   unsigned tag,
+//                                                   const Metadata *metadata)
+FUNCTION(SingletonEnumDestructiveInjectEnumTag,
+         swift_singletonEnum_destructiveInjectEnumTag,
+         C_CC, AlwaysAvailable,
+         RETURNS(VoidTy),
+         ARGS(Int8PtrTy, Int32Ty, TypeMetadataPtrTy),
+         ATTRS(NoUnwind, WillReturn),
+         EFFECT(NoEffect))
+
 // unsigned swift_enumSimple_getEnumTag(swift::OpaqueValue *address,
 //                                      const Metadata *metadata);
 FUNCTION(EnumSimpleGetEnumTag,

lib/IRGen/GenValueWitness.cpp

@@ -940,7 +940,7 @@ getDestructiveInjectEnumTagFunction(IRGenModule &IGM,
        !isRuntimeInstatiatedLayoutString(IGM, typeLayoutEntry))) {
     return nullptr;
   } else if (typeLayoutEntry->isSingleton()) {
-    return nullptr;
+    return IGM.getSingletonEnumDestructiveInjectEnumTagFn();
   } else if (!typeLayoutEntry->isFixedSize(IGM)) {
     if (typeLayoutEntry->isMultiPayloadEnum()) {
       return IGM.getMultiPayloadEnumGenericDestructiveInjectEnumTagFn();

stdlib/public/runtime/BytecodeLayouts.cpp

@@ -659,6 +659,11 @@ extern "C" unsigned swift_singletonEnum_getEnumTag(swift::OpaqueValue *address,
   return 0;
 }
 
+extern "C" void swift_singletonEnum_destructiveInjectEnumTag(
+    swift::OpaqueValue *address, unsigned tag, const Metadata *metadata) {
+  return;
+}
+
 template <typename T>
 static inline T handleSinglePayloadEnumSimpleTag(
     LayoutStringReader &reader, uint8_t *addr,

stdlib/public/runtime/BytecodeLayouts.h

@@ -121,6 +121,10 @@ SWIFT_RUNTIME_EXPORT
 unsigned swift_singletonEnum_getEnumTag(swift::OpaqueValue *address,
                                         const Metadata *metadata);
 SWIFT_RUNTIME_EXPORT
+void swift_singletonEnum_destructiveInjectEnumTag(swift::OpaqueValue *address,
+                                                  unsigned tag,
+                                                  const Metadata *metadata);
+SWIFT_RUNTIME_EXPORT
 unsigned swift_enumSimple_getEnumTag(swift::OpaqueValue *address,
                                      const Metadata *metadata);
 SWIFT_RUNTIME_EXPORT

test/Interpreter/layout_string_witnesses_dynamic.swift

@@ -670,6 +670,22 @@ func testResilientMultiPayloadEnumGenericInjectTag() {
 
 testResilientMultiPayloadEnumGenericInjectTag()
 
+@inline(never)
+func matchResilientSingletonEnumTag(_ x: ResilientSingletonEnum) -> Int {
+    return switch x {
+    case .nonEmpty: 0
+    }
+}
+
+func testResilientSingletonEnumGenericInjectTag() {
+    let x = ResilientSingletonEnum.nonEmpty(SimpleClass(x: 23))
+
+    // CHECK: Enum case: 0
+    print("Enum case: \(matchResilientSingletonEnumTag(x))")
+}
+
+testResilientSingletonEnumGenericInjectTag()
+
 #if os(macOS)
 
 import Foundation