Merge pull request swiftlang#76880 from rjmccall/actor-delegating-init-isolation

Hop to the current isolation properly in delegating async actor initializers

Author: rjmccall

include/swift/AST/DiagnosticsSIL.def

@@ -111,6 +111,9 @@ ERROR(exclusivity_access_required_unknown_decl_moveonly,none,
 NOTE(exclusivity_conflicting_access,none,
      "conflicting access is here", ())
 
+ERROR(unsupported_sil_builtin,none,
+      "builtin '%0' is not supported by SIL generation", (StringRef))
+
 ERROR(unsupported_c_function_pointer_conversion,none,
       "C function pointer signature %0 is not compatible with expected type %1",
       (Type, Type))

include/swift/SIL/AddressWalker.h

@@ -276,6 +276,8 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) && {
         case BuiltinValueKind::GetEnumTag:
         case BuiltinValueKind::InjectEnumTag:
         case BuiltinValueKind::AddressOfRawLayout:
+        case BuiltinValueKind::FlowSensitiveSelfIsolation:
+        case BuiltinValueKind::FlowSensitiveDistributedSelfIsolation:
           callVisitUse(op);
           continue;
         default:

lib/SIL/IR/OperandOwnership.cpp

@@ -914,14 +914,33 @@ BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, EndAsyncLetLifetime)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, CreateTaskGroup)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, CreateTaskGroupWithFlags)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, DestroyTaskGroup)
-BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, FlowSensitiveSelfIsolation)
-BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, FlowSensitiveDistributedSelfIsolation)
 
 BUILTIN_OPERAND_OWNERSHIP(ForwardingConsume, COWBufferForReading)
 
 // This should actually never be seen in SIL
 BUILTIN_OPERAND_OWNERSHIP(GuaranteedForwarding, ExtractFunctionIsolation)
 
+static OperandOwnership
+visitAnyFlowSensitiveSelfIsolation(BuiltinInst *bi) {
+  // In potentially-delegating initializers, the operand will be the
+  // address of the box instead of the actor instance.
+  auto operand = bi->getOperand(0);
+  if (operand->getType().isAddress())
+    return OperandOwnership::TrivialUse;
+  return OperandOwnership::InstantaneousUse;
+}
+
+OperandOwnership
+OperandOwnershipBuiltinClassifier
+::visitFlowSensitiveSelfIsolation(BuiltinInst *bi, StringRef attr) {
+  return visitAnyFlowSensitiveSelfIsolation(bi);
+}
+OperandOwnership
+OperandOwnershipBuiltinClassifier
+::visitFlowSensitiveDistributedSelfIsolation(BuiltinInst *bi, StringRef attr) {
+  return visitAnyFlowSensitiveSelfIsolation(bi);
+}
+
 OperandOwnership
 OperandOwnershipBuiltinClassifier
 ::visitStartAsyncLetWithLocalBuffer(BuiltinInst *bi, StringRef attr) {

lib/SILGen/SILGenApply.cpp

@@ -5709,8 +5709,10 @@ RValue SILGenFunction::emitApply(
     }
 
     breadcrumb = emitHopToTargetExecutor(loc, executor);
-  } else if (ExpectedExecutor &&
-             (substFnType->isAsync() || calleeTypeInfo.foreign.async)) {
+  } else if ((substFnType->isAsync() || calleeTypeInfo.foreign.async) &&
+             ExpectedExecutor.isNecessary()) {
+    assert(F.isAsync());
+
     // Otherwise, if we're in an actor method ourselves, and we're calling into
     // any sort of async function, we'll want to make sure to hop back to our
     // own executor afterward, since the callee could have made arbitrary hops

lib/SILGen/SILGenBridging.cpp

@@ -2090,6 +2090,11 @@ void SILGenFunction::emitForeignToNativeThunk(SILDeclRef thunk) {
   if (nativeFnTy->isAsync()) {
     foreignAsync = fd->getForeignAsyncConvention();
     assert(foreignAsync && "couldn't find foreign async convention?!");
+
+    // We might switch to to the callee's actor as part of making the call,
+    // but we don't need to switch back afterwards because we're going to
+    // immediately return.
+    ExpectedExecutor.setUnnecessary();
   }
   std::optional<ForeignErrorConvention> foreignError;
   if (nativeFnTy->hasErrorResult()) {

lib/SILGen/SILGenBuiltin.cpp

@@ -1493,8 +1493,16 @@ static ManagedValue emitBuiltinEndAsyncLet(
 static ManagedValue emitBuiltinGetCurrentExecutor(
     SILGenFunction &SGF, SILLocation loc, SubstitutionMap subs,
     PreparedArguments &&preparedArgs, SGFContext C) {
-  return ManagedValue::forObjectRValueWithoutOwnership(
-      SGF.emitGetCurrentExecutor(loc));
+
+  // We don't support this builtin anymore in SILGen.
+  // TODO: just remove it?
+  SGF.SGM.diagnose(loc, diag::unsupported_sil_builtin,
+                   getBuiltinName(BuiltinValueKind::GetCurrentExecutor));
+
+  auto &ctx = SGF.getASTContext();
+  auto executorType = SILType::getPrimitiveObjectType(ctx.TheExecutorType);
+  auto optionalExecutorType = SILType::getOptionalType(executorType);
+  return SGF.emitUndef(optionalExecutorType);
 }
 
 // Emit SIL for sizeof/strideof/alignof.