Merge pull request swiftlang#76707 from DougGregor/sendable-conformance-evolution-old-deployment

Use "resilient conformance" logic for deciding protocol dependencies involving Sendable

Author: DougGregor

lib/IRGen/GenProto.cpp

@@ -959,8 +959,13 @@ namespace {
 
 /// Return true if the witness table requires runtime instantiation to
 /// handle resiliently-added requirements with default implementations.
+///
+/// If disableOptimizations is true, skip optimizations that treat
+/// formally-resilient conformances as non-resilient.
 bool IRGenModule::isResilientConformance(
-    const NormalProtocolConformance *conformance) {
+    const NormalProtocolConformance *conformance,
+    bool disableOptimizations
+) {
   // If the protocol is not resilient, the conformance is not resilient
   // either.
   bool shouldTreatProtocolNonResilient =
@@ -992,16 +997,18 @@ bool IRGenModule::isResilientConformance(
   // This is an optimization -- a conformance of a non-generic type cannot
   // resiliently become dependent.
   if (!conformance->getDeclContext()->isGenericContext() &&
-      conformanceModule == conformance->getProtocol()->getParentModule())
+      conformanceModule == conformance->getProtocol()->getParentModule() &&
+      !disableOptimizations)
     return false;
 
   // We have a resilient conformance.
   return true;
 }
 
-bool IRGenModule::isResilientConformance(const RootProtocolConformance *root) {
+bool IRGenModule::isResilientConformance(const RootProtocolConformance *root,
+                                         bool disableOptimizations) {
   if (auto normal = dyn_cast<NormalProtocolConformance>(root))
-    return isResilientConformance(normal);
+    return isResilientConformance(normal, disableOptimizations);
   // Self-conformances never require this.
   return false;
 }
@@ -1185,7 +1192,9 @@ bool IRGenModule::isDependentConformance(
     const RootProtocolConformance *conformance) {
   llvm::SmallPtrSet<const NormalProtocolConformance *, 4> visited;
   return ::isDependentConformance(
-      *this, conformance, conformance->getProtocol()->isResilient(), visited);
+      *this, conformance,
+      isResilientConformance(conformance, /*disableOptimizations=*/true),
+      visited);
 }
 
 static llvm::Value *

lib/IRGen/IRGenModule.h

@@ -1119,8 +1119,10 @@ class IRGenModule {
 
   TypeExpansionContext getMaximalTypeExpansionContext() const;
 
-  bool isResilientConformance(const NormalProtocolConformance *conformance);
-  bool isResilientConformance(const RootProtocolConformance *root);
+  bool isResilientConformance(const NormalProtocolConformance *conformance,
+                              bool disableOptimizations = false);
+  bool isResilientConformance(const RootProtocolConformance *root,
+                              bool disableOptimizations = false);
   bool isDependentConformance(const RootProtocolConformance *conformance);
 
   Alignment getCappedAlignment(Alignment alignment);

test/IRGen/protocol_resilience_sendable.swift

@@ -6,11 +6,37 @@
 // RUN: %target-swift-frontend -I %t -emit-ir %s -target %target-cpu-apple-macos14.0 | %FileCheck %s -DINT=i%target-ptrsize -check-prefix=CHECK-USAGE -check-prefix=CHECK-USAGE-BEFORE
 // RUN: %target-swift-frontend -I %t -emit-ir %s -target %target-cpu-apple-macos15.0 | %FileCheck %s -DINT=i%target-ptrsize -check-prefix=CHECK-USAGE -check-prefix=CHECK-USAGE-AFTER
 
+// RUN: %target-swift-frontend -I %t -emit-ir %s -target %target-cpu-apple-macos14.0 -enable-library-evolution | %FileCheck %s -DINT=i%target-ptrsize -check-prefix=CHECK-USAGE -check-prefix=CHECK-USAGE-BEFORE
+// RUN: %target-swift-frontend -I %t -emit-ir %s -target %target-cpu-apple-macos15.0 -enable-library-evolution | %FileCheck %s -DINT=i%target-ptrsize -check-prefix=CHECK-USAGE -check-prefix=CHECK-USAGE-AFTER
+
 // REQUIRES: OS=macosx
 
 import resilient_protocol
 import non_resilient_protocol
 
+// CHECK-USAGE: @"$s28protocol_resilience_sendable9LocalTypeVAA0D11SubProtocolAAWP" = hidden constant [3 x ptr] [
+// CHECK-USAGE-SAME: ptr @"$s28protocol_resilience_sendable9LocalTypeVAA0D11SubProtocolAAMc",
+// CHECK-USAGE-SAME: ptr @"$s28protocol_resilience_sendable9LocalTypeVAA0D8ProtocolAAWP",
+// CHECK-USAGE-SAME: ptr @"$s28protocol_resilience_sendable9LocalTypeVAA0D11SubProtocolA2aDP9subMethodyyFTW"
+public protocol LocalProtocol: Sendable {
+  func method()
+}
+
+protocol LocalSubProtocol: Sendable, LocalProtocol {
+  func subMethod()
+}
+
+struct LocalType: Sendable, LocalSubProtocol {
+  func method() { }
+  func subMethod() { }
+}
+
+func acceptLocalProtocol<T: LocalProtocol>(_: T.Type) { }
+func testLocalType() {
+  acceptLocalProtocol(LocalType.self)
+}
+
+
 func acceptResilientSendableBase<T: ResilientSendableBase>(_: T.Type) { }
 
 // CHECK-USAGE: define{{.*}}swiftcc void @"$s28protocol_resilience_sendable25passResilientSendableBaseyyF"()