IRGen: Fix isResilientConformance() check

If the conforming type is generic, we have to treat the conformance as
resilient if it is defined outside of the current module.

This is because it can resiliently change from being non-dependent
to dependent.

Author: slavapestov

lib/IRGen/GenProto.cpp

@@ -955,10 +955,21 @@ bool IRGenModule::isResilientConformance(
   if (!conformance->getProtocol()->isResilient())
     return false;
 
-  // If the protocol is in the same module as the conformance, we're
-  // not resilient.
-  if (conformance->getDeclContext()->getParentModule()
-      == conformance->getProtocol()->getParentModule())
+  auto *conformanceModule = conformance->getDeclContext()->getParentModule();
+
+  // If the protocol and the conformance are both in the current module,
+  // they're not resilient.
+  if (conformanceModule == getSwiftModule() &&
+      conformanceModule == conformance->getProtocol()->getParentModule())
+    return false;
+
+  // If the protocol and the conformance are in the same module and the
+  // conforming type is not generic, they're not resilient.
+  //
+  // This is an optimization -- a conformance of a non-generic type cannot
+  // resiliently become dependent.
+  if (!conformance->getDeclContext()->isGenericContext() &&
+      conformanceModule == conformance->getProtocol()->getParentModule())
     return false;
 
   // We have a resilient conformance.

test/IRGen/conformance_resilience.swift

@@ -0,0 +1,28 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -enable-resilience -emit-module-path=%t/resilient_protocol.swiftmodule -module-name=resilient_protocol %S/../Inputs/resilient_protocol.swift
+// RUN: %target-swift-frontend -I %t -emit-ir -enable-resilience %s | %FileCheck %s -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -I %t -emit-ir -enable-resilience -O %s
+
+import resilient_protocol
+
+// CHECK-LABEL: define{{( protected)?}}  swiftcc void @"$s22conformance_resilience14useConformanceyyx18resilient_protocol22OtherResilientProtocolRzlF"(%swift.opaque* noalias nocapture, %swift.type* %T, i8** %T.OtherResilientProtocol)
+public func useConformance<T : OtherResilientProtocol>(_: T) {}
+
+// CHECK-LABEL: define{{( protected)?}} swiftcc void @"$s22conformance_resilience14getConformanceyy18resilient_protocol7WrapperVyxGlF"(%swift.opaque* noalias nocapture, %swift.type* %T)
+public func getConformance<T>(_ w: Wrapper<T>) {
+  // CHECK: [[RESPONSE:%.*]] = call swiftcc %swift.metadata_response @"$s18resilient_protocol7WrapperVMa"([[INT]] 0, %swift.type* %T)
+  // CHECK: [[META:%.*]] = extractvalue %swift.metadata_response [[RESPONSE]], 0
+  // CHECK: [[WTABLE:%.*]] = call i8** @swift_getWitnessTable(%swift.protocol_conformance_descriptor* @"$s18resilient_protocol7WrapperVyxGAA22OtherResilientProtocolAAMc", %swift.type* [[META]], i8*** undef)
+  // CHECK: call swiftcc void @"$s22conformance_resilience14useConformanceyyx18resilient_protocol22OtherResilientProtocolRzlF"(%swift.opaque* noalias nocapture %0, %swift.type* [[META]], i8** [[WTABLE]])
+  // CHECK: ret void
+  useConformance(w)
+}
+
+// CHECK-LABEL: define{{( protected)?}} swiftcc void @"$s22conformance_resilience14getConformanceyy18resilient_protocol15ConcreteWrapperVF"(%swift.opaque* noalias nocapture)
+public func getConformance(_ w: ConcreteWrapper) {
+  // CHECK: [[RESPONSE:%.*]] = call swiftcc %swift.metadata_response @"$s18resilient_protocol15ConcreteWrapperVMa"([[INT]] 0)
+  // CHECK: [[META:%.*]] = extractvalue %swift.metadata_response [[RESPONSE]], 0
+  // CHECK: call swiftcc void @"$s22conformance_resilience14useConformanceyyx18resilient_protocol22OtherResilientProtocolRzlF"(%swift.opaque* noalias nocapture %0, %swift.type* [[META]], i8** @"$s18resilient_protocol15ConcreteWrapperVAA22OtherResilientProtocolAAWP")
+  // CHECK: ret void
+  useConformance(w)
+}

test/Inputs/resilient_protocol.swift

@@ -30,6 +30,8 @@ public protocol ProtocolWithRequirements {
 
 public struct Wrapper<T>: OtherResilientProtocol { }
 
+public struct ConcreteWrapper: OtherResilientProtocol { }
+
 public protocol ProtocolWithAssocTypeDefaults {
   associatedtype T1 = Self
   associatedtype T2: OtherResilientProtocol = Wrapper<T1>

validation-test/Evolution/Inputs/conformance_reference.swift

@@ -0,0 +1,36 @@
+
+public func getVersion() -> Int {
+#if BEFORE
+  return 0
+#else
+  return 1
+#endif
+}
+
+
+public protocol BaseProtocol {
+#if AFTER
+  associatedtype Assoc = Self
+#endif
+}
+
+public protocol DerivedProtocol : BaseProtocol {}
+
+
+public struct FirstGeneric<T> : BaseProtocol {
+  public init() {}
+}
+
+public struct SecondGeneric<T> : DerivedProtocol {
+  public init() {}
+}
+
+extension BaseProtocol {
+  public func getMeAType() -> Any.Type {
+#if BEFORE
+    return Self.self
+#else
+    return Assoc.self
+#endif
+  }
+}

validation-test/Evolution/test_conformance_reference.swift

@@ -0,0 +1,39 @@
+// RUN: %target-resilience-test --no-symbol-diff
+// REQUIRES: executable_test
+
+import StdlibUnittest
+import conformance_reference
+
+
+var ConformanceReferenceTest = TestSuite("ConformanceReference")
+
+
+func useBase<T : BaseProtocol>(_: T) {}
+
+ConformanceReferenceTest.test("BaseConformance") {
+  useBase(FirstGeneric<Int>())
+  useBase(SecondGeneric<Int>())
+}
+
+
+func useDerived<T : DerivedProtocol>(_: T) {}
+
+ConformanceReferenceTest.test("DerivedConformance") {
+  useDerived(SecondGeneric<Int>())
+}
+
+
+protocol EvenMoreDerivedProtocol : DerivedProtocol {}
+
+extension FirstGeneric : EvenMoreDerivedProtocol {}
+
+func useEvenMoreDerived<T : EvenMoreDerivedProtocol>(_ t: T) -> Any.Type {
+  return t.getMeAType()
+}
+
+ConformanceReferenceTest.test("EvenMoreDerivedConformance") {
+  expectTrue(FirstGeneric<Int>.self == useEvenMoreDerived(FirstGeneric<Int>()))
+  expectTrue(FirstGeneric<String>.self == useEvenMoreDerived(FirstGeneric<String>()))
+}
+
+runAllTests()