Merge pull request swiftlang#76133 from slavapestov/sync-local-func-isolation

SIL: Synchronous local functions don't need to capture the isolation parameter

Author: slavapestov

lib/SIL/IR/TypeLowering.cpp

@@ -4485,26 +4485,6 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
     PrettyStackTraceAnyFunctionRef("lowering local captures", curFn);
     collectCaptures(curFn.getCaptureInfo());
 
-    if (auto *afd = curFn.getAbstractFunctionDecl()) {
-      // If a local function inherits isolation from the enclosing context,
-      // make sure we capture the isolated parameter, if we haven't already.
-      if (afd->isLocalCapture()) {
-        auto actorIsolation = getActorIsolation(afd);
-        if (actorIsolation.getKind() == ActorIsolation::ActorInstance) {
-          if (auto *var = actorIsolation.getActorInstance()) {
-            assert(isa<ParamDecl>(var));
-            recordCapture(CapturedValue(var, 0, afd->getLoc()));
-	    if (var->getInterfaceType()->hasTypeParameter()) {
-	      // If the isolated parameter is of a generic (actor)
-	      // type, we need to treat as if the local function is
-	      // generic.
-	      capturesGenericParams = true;
-	    }
-          }
-        }
-      }
-    }
-
     // A function's captures also include its default arguments, because
     // when we reference a function we don't track which default arguments
     // are referenced too.

lib/SILOptimizer/Utils/SILIsolationInfo.cpp

@@ -892,10 +892,9 @@ SILIsolationInfo SILIsolationInfo::get(SILArgument *arg) {
   }
 
   // Otherwise, if we do not have an isolated argument and are not in an
-  // alloactor, then we might be isolated via global isolation.
+  // allocator, then we might be isolated via global isolation.
   if (auto functionIsolation = fArg->getFunction()->getActorIsolation()) {
     if (functionIsolation.isActorIsolated()) {
-      assert(functionIsolation.isGlobalActor());
       if (functionIsolation.isGlobalActor()) {
         return SILIsolationInfo::getGlobalActorIsolated(
             fArg, functionIsolation.getGlobalActor());

lib/Sema/TypeCheckCaptures.cpp

@@ -234,10 +234,9 @@ class FindCapturedVars : public ASTWalker {
 
     // Visit the type of the capture, if it isn't a class reference, since
     // we'd need the metadata to do so.
-    if (VD->hasInterfaceType()
-        && (!ObjC
+    if (!ObjC
             || !isa<VarDecl>(VD)
-            || !cast<VarDecl>(VD)->getTypeInContext()->hasRetainablePointerRepresentation()))
+            || !cast<VarDecl>(VD)->getTypeInContext()->hasRetainablePointerRepresentation())
       checkType(VD->getInterfaceType(), VD->getLoc());
   }
 
@@ -752,6 +751,18 @@ CaptureInfo CaptureInfoRequest::evaluate(Evaluator &evaluator,
     finder.checkType(type, AFD->getLoc());
   }
 
+  if (AFD->isLocalCapture() && AFD->hasAsync()) {
+    // If a local function inherits isolation from the enclosing context,
+    // make sure we capture the isolated parameter, if we haven't already.
+    auto actorIsolation = getActorIsolation(AFD);
+    if (actorIsolation.getKind() == ActorIsolation::ActorInstance) {
+      if (auto *var = actorIsolation.getActorInstance()) {
+        assert(isa<ParamDecl>(var));
+        finder.addCapture(CapturedValue(var, 0, AFD->getLoc()));
+      }
+    }
+  }
+
   // Extensions of generic ObjC functions can't use generic parameters from
   // their context.
   if (finder.hasGenericParamCaptures()) {

test/SILGen/local_function_isolation.swift

@@ -59,11 +59,32 @@ func test() async {}
 // local/nested function.
 actor GenericActor<K> {
   var i: Int = 0
-  private func outerFunc() {
-    func accessSelf() -> Int {
-      // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation12GenericActorC9outerFunc33_7B9E2B75110B8600A136A469D51CAF2BLLyyF10accessSelfL_SiylF : $@convention(thin) <K> (@sil_isolated @guaranteed GenericActor<K>) -> Int {
+  func outerFunc() async {
+    func accessSelf() async -> Int {
+      // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation12GenericActorC9outerFuncyyYaF10accessSelfL_SiyYalF : $@convention(thin) @async <K> (@sil_isolated @guaranteed GenericActor<K>) -> Int {
       return 0
     }
-    print(accessSelf())
+    await print(accessSelf())
   }
 }
+
+// Make sure defer doesn't capture anything.
+actor DeferInsideInitActor {
+  init(foo: ()) async throws {
+    // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation20DeferInsideInitActorC3fooACyt_tYaKcfc6$deferL_yyF : $@convention(thin) () -> () {
+    defer {}
+    try self.init()
+  }
+}
+
+actor NestedAsyncInSyncActor {
+  public func outer() async {
+    // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation22NestedAsyncInSyncActorC5outeryyYaF6middleL_yyF : $@convention(thin) (@sil_isolated @guaranteed NestedAsyncInSyncActor) -> () {
+    func middle() {
+      // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation22NestedAsyncInSyncActorC5outeryyYaF6middleL_yyF5innerL_yyYaF : $@convention(thin) @async (@sil_isolated @guaranteed NestedAsyncInSyncActor) -> () {
+      func inner() async {}
+      _ = inner
+    }
+    _ = middle
+  }
+}