[IRGen] Fix enum metadata instantiation for resilient payload

The metadata can't be constant when we generate a layout string at runtime.

Author: drexin

lib/IRGen/GenMeta.cpp

@@ -2581,16 +2581,17 @@ void irgen::emitLazyTypeContextDescriptor(IRGenModule &IGM,
     auto genericSig =
         lowered.getNominalOrBoundGenericNominal()->getGenericSignature();
     hasLayoutString = !!typeLayoutEntry->layoutString(IGM, genericSig);
-  }
 
-  if (auto sd = dyn_cast<StructDecl>(type)) {
-    if (IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnessesInstantiation) &&
+    if (!hasLayoutString &&
+        IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnessesInstantiation) &&
         IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation) {
       hasLayoutString |= requiresForeignTypeMetadata(type) ||
-        needsSingletonMetadataInitialization(IGM, type) ||
-        (type->isGenericContext() && !isa<FixedTypeInfo>(ti));
+          needsSingletonMetadataInitialization(IGM, type) ||
+          (type->isGenericContext() && !isa<FixedTypeInfo>(ti));
     }
+  }
 
+  if (auto sd = dyn_cast<StructDecl>(type)) {
     StructContextDescriptorBuilder(IGM, sd, requireMetadata,
                                    hasLayoutString).emit();
   } else if (auto ed = dyn_cast<EnumDecl>(type)) {
@@ -5487,6 +5488,24 @@ namespace {
       return emitValueWitnessTable(relativeReference);
     }
 
+    bool hasInstantiatedLayoutString() {
+      if (IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnessesInstantiation) &&
+          IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation) {
+        return needsSingletonMetadataInitialization(IGM, Target);
+      }
+
+      return false;
+    }
+
+    bool hasLayoutString() {
+      if (!IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnesses) ||
+          !IGM.getOptions().EnableLayoutStringValueWitnesses) {
+        return false;
+      }
+
+      return hasInstantiatedLayoutString() || !!getLayoutString();
+    }
+
     llvm::Constant *emitLayoutString() {
       if (!IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnesses) ||
           !IGM.getOptions().EnableLayoutStringValueWitnesses)
@@ -5521,7 +5540,7 @@ namespace {
 
     llvm::Constant *emitNominalTypeDescriptor() {
       auto descriptor = EnumContextDescriptorBuilder(
-                            IGM, Target, RequireMetadata, !!getLayoutString())
+                            IGM, Target, RequireMetadata, hasLayoutString())
                             .emit();
       return descriptor;
     }
@@ -5570,7 +5589,7 @@ namespace {
     }
 
     bool canBeConstant() {
-      return !HasUnfilledPayloadSize;
+      return !HasUnfilledPayloadSize && !hasInstantiatedLayoutString();
     }
   };
 

stdlib/public/runtime/Enum.cpp

@@ -222,6 +222,8 @@ XIElement findXIElement(const Metadata *type) {
 void swift::swift_initEnumMetadataSinglePayloadWithLayoutString(
     EnumMetadata *self, EnumLayoutFlags layoutFlags,
     const Metadata *payloadType, unsigned emptyCases) {
+  assert(self->hasLayoutString());
+
   auto *payloadLayout = payloadType->getTypeLayout();
   size_t payloadSize = payloadLayout->size;
   unsigned payloadNumExtraInhabitants = payloadLayout->getNumExtraInhabitants();

test/Interpreter/Inputs/layout_string_witnesses_types_resilient.swift

@@ -78,3 +78,9 @@ public func getResilientSinglePayloadEnumSimpleEmpty0() -> ResilientSinglePayloa
 public func getResilientSingletonEnumNonEmpty(_ x: AnyObject) -> ResilientSingletonEnum {
     return .nonEmpty(x)
 }
+
+public enum ResilientSinglePayloadEnum {
+    case empty0
+    case empty1
+    case nonEmpty(AnyObject, Int)
+}

test/Interpreter/layout_string_witnesses_dynamic.swift

@@ -686,6 +686,22 @@ func testResilientSingletonEnumGenericInjectTag() {
 
 testResilientSingletonEnumGenericInjectTag()
 
+enum ResilientPayloadSinglePayloadEnum {
+    case empty0
+    case empty1
+    case empty2
+    case nonEmpty(ResilientSinglePayloadEnum, Int)
+}
+
+func testResilientPayloadSinglePayloadEnum() {
+    let xxx = ResilientPayloadSinglePayloadEnum.nonEmpty(.empty0, 1)
+
+    // CHECK: nonEmpty(layout_string_witnesses_types_resilient.ResilientSinglePayloadEnum.empty0, 1)
+    print(xxx)
+}
+
+testResilientPayloadSinglePayloadEnum()
+
 #if os(macOS)
 
 import Foundation