ensure that async initializers for reference and value

types correctly hop to the right global-actor in their
prolog.

Author: kavon

lib/SILGen/SILGenConstructor.cpp

@@ -12,6 +12,7 @@
 
 #include "ArgumentSource.h"
 #include "Conversion.h"
+#include "ExecutorBreadcrumb.h"
 #include "Initialization.h"
 #include "LValue.h"
 #include "RValue.h"
@@ -357,6 +358,13 @@ void SILGenFunction::emitValueConstructor(ConstructorDecl *ctor) {
                   ctor->getThrowsLoc());
   emitConstructorMetatypeArg(*this, ctor);
 
+  // Make sure we've hopped to the right global actor, if any.
+  if (ctor->hasAsync()) {
+    SILLocation prologueLoc(selfDecl);
+    prologueLoc.markAsPrologue();
+    emitConstructorPrologActorHop(prologueLoc, getActorIsolation(ctor));
+  }
+
   // Create a basic block to jump to for the implicit 'self' return.
   // We won't emit this until after we've emitted the body.
   // The epilog takes a void return because the return of 'self' is implicit.
@@ -662,6 +670,18 @@ static void emitDefaultActorInitialization(SILGenFunction &SGF,
                       { self.borrow(SGF, loc).getValue() });
 }
 
+void SILGenFunction::emitConstructorPrologActorHop(
+                                           SILLocation loc,
+                                           Optional<ActorIsolation> maybeIso) {
+  if (!maybeIso)
+    return;
+
+  if (auto executor = emitExecutor(loc, *maybeIso, None)) {
+    ExpectedExecutor = *executor;
+    B.createHopToExecutor(loc, *executor);
+  }
+}
+
 void SILGenFunction::emitClassConstructorInitializer(ConstructorDecl *ctor) {
   MagicFunctionName = SILGenModule::getMagicFunctionName(ctor);
 
@@ -724,6 +744,13 @@ void SILGenFunction::emitClassConstructorInitializer(ConstructorDecl *ctor) {
   SILType selfTy = getLoweredLoadableType(selfDecl->getType());
   ManagedValue selfArg = B.createInputFunctionArgument(selfTy, selfDecl);
 
+  // Make sure we've hopped to the right global actor, if any.
+  if (ctor->hasAsync() && !selfClassDecl->isActor()) {
+    SILLocation prologueLoc(selfDecl);
+    prologueLoc.markAsPrologue();
+    emitConstructorPrologActorHop(prologueLoc, getActorIsolation(ctor));
+  }
+
   if (!NeedsBoxForSelf) {
     SILLocation PrologueLoc(selfDecl);
     PrologueLoc.markAsPrologue();

lib/SILGen/SILGenFunction.h

@@ -839,6 +839,17 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                             Optional<ActorIsolation> actorIso,
                             Optional<ManagedValue> actorSelf);
 
+  /// A version of `emitHopToTargetActor` that is specialized to the needs
+  /// of various types of ConstructorDecls, like class or value initializers,
+  /// because their prolog emission is not the same as for regular functions.
+  ///
+  /// This function emits the appropriate hop_to_executor for a constructor's
+  /// prologue.
+  ///
+  /// NOTE: this does not support actor initializers!
+  void emitConstructorPrologActorHop(SILLocation loc,
+                                     Optional<ActorIsolation> actorIso);
+
   /// Emit the executor for the given actor isolation.
   Optional<SILValue> emitExecutor(SILLocation loc,
                                   ActorIsolation isolation,