Unify @_predatesConcurrency behavior for dynamic data race detection

Don't treat "unsafe" and safe global actor isolation differently with
respect to dynamic data race detection, because this
`@_predatesConcurrency` is only supposed to affect the interface (not
the implementation).

Author: DougGregor

lib/SILGen/SILGenProlog.cpp

@@ -560,34 +560,30 @@ void SILGenFunction::emitProlog(CaptureInfo captureInfo,
         dyn_cast_or_null<AbstractFunctionDecl>(FunctionDC->getAsDecl())) {
     auto actorIsolation = getActorIsolation(funcDecl);
     switch (actorIsolation.getKind()) {
-      case ActorIsolation::Unspecified:
-      case ActorIsolation::Independent:
-        // If this is an async function that has an isolated parameter, hop
-        // to it.
-        if (F.isAsync()) {
-          for (auto param : *funcDecl->getParameters()) {
-            if (param->isIsolated()) {
-              auto loc = RegularLocation::getAutoGeneratedLocation(F.getLocation());
-              Type actorType = param->getType();
-              RValue actorInstanceRV = emitRValueForDecl(
-                  loc, param, actorType, AccessSemantics::Ordinary);
-              ManagedValue actorInstance =
-                  std::move(actorInstanceRV).getScalarValue();
-              ExpectedExecutor = emitLoadActorExecutor(loc, actorInstance);
-              break;
-            }
+    case ActorIsolation::Unspecified:
+    case ActorIsolation::Independent:
+      // If this is an async function that has an isolated parameter, hop
+      // to it.
+      if (F.isAsync()) {
+        for (auto param : *funcDecl->getParameters()) {
+          if (param->isIsolated()) {
+            auto loc = RegularLocation::getAutoGeneratedLocation(F.getLocation());
+            Type actorType = param->getType();
+            RValue actorInstanceRV = emitRValueForDecl(
+                loc, param, actorType, AccessSemantics::Ordinary);
+            ManagedValue actorInstance =
+                std::move(actorInstanceRV).getScalarValue();
+            ExpectedExecutor = emitLoadActorExecutor(loc, actorInstance);
+            break;
           }
         }
-
-        break;
-
-      case ActorIsolation::GlobalActorUnsafe:
-        break;
-
-      case ActorIsolation::DistributedActorInstance: {
-        // TODO: perhaps here we can emit our special handling to make a message?
-        LLVM_FALLTHROUGH;
       }
+      break;
+
+    case ActorIsolation::DistributedActorInstance: {
+      // TODO: perhaps here we can emit our special handling to make a message?
+      LLVM_FALLTHROUGH;
+    }
 
     case ActorIsolation::ActorInstance: {
       assert(selfParam && "no self parameter for ActorInstance isolation");
@@ -605,6 +601,7 @@ void SILGenFunction::emitProlog(CaptureInfo captureInfo,
     }
 
     case ActorIsolation::GlobalActor:
+    case ActorIsolation::GlobalActorUnsafe:
       if (F.isAsync() || wantDataRaceChecks) {
         ExpectedExecutor =
           emitLoadGlobalActorExecutor(actorIsolation.getGlobalActor());

test/SILGen/check_executor.swift

@@ -13,6 +13,10 @@ import _Concurrency
 // CHECK-CANONICAL: function_ref @$ss22_checkExpectedExecutor14_filenameStart01_D6Length01_D7IsASCII5_line9_executoryBp_BwBi1_BwBetF
 @MainActor public func onMainActor() { }
 
+// CHECK-CANONICAL-LABEL: sil [ossa] @$s4test17onMainActorUnsafeyyF
+// CHECK-CANONICAL: function_ref @$ss22_checkExpectedExecutor14_filenameStart01_D6Length01_D7IsASCII5_line9_executoryBp_BwBi1_BwBetF
+@_predatesConcurrency @MainActor public func onMainActorUnsafe() { }
+
 func takeClosure(_ fn: @escaping () -> Int) { }
 
 @_predatesConcurrency func takeUnsafeMainActorClosure(_ fn: @MainActor @escaping () -> Int) { }