Revert "Merge pull request #38938 from drexin/wip-dist-resolve" (#38994)

This reverts commit a4f3f2fb48, reversing
changes made to 8cf6c2e71b.

lib/SILGen/SILGenDistributed.cpp

@@ -70,34 +70,6 @@ static void emitDistributedIfRemoteBranch(SILGenFunction &SGF,
   B.createCondBranch(Loc, isRemoteResultUnwrapped, isRemoteBB, isLocalBB);
 }
 
-static AbstractFunctionDecl *lookupActorTransportResolveFunc(ASTContext &C) {
-  auto transportDecl = C.getActorTransportDecl();
-
-  for (auto decl : transportDecl->lookupDirect(DeclName(C.Id_resolve)))
-    if (auto funcDecl = dyn_cast<AbstractFunctionDecl>(decl))
-      return funcDecl;
-
-  llvm_unreachable("Missing ActorTransport.resolve function");
-}
-
-static VarDecl *lookupActorTransportProperty(ASTContext &C, ClassDecl *cd,
-                                             SILValue selfValue) {
-  auto transportVarDeclRefs = cd->lookupDirect(C.Id_actorTransport);
-  assert(transportVarDeclRefs.size() == 1);
-  return dyn_cast<VarDecl>(transportVarDeclRefs.front());
-}
-
-static EnumElementDecl *lookupEnumCase(ASTContext &C, EnumDecl *target,
-                                       Identifier identifier) {
-  auto elementDecls = target->lookupDirect(DeclName(identifier));
-  if (elementDecls.empty())
-    return nullptr;
-
-  auto *elementDecl = elementDecls.front();
-
-  return dyn_cast<EnumElementDecl>(elementDecl);
-}
-
 /******************************************************************************/
 /****************** DISTRIBUTED ACTOR STORAGE INITIALIZATION ******************/
 /******************************************************************************/
@@ -148,7 +120,6 @@ static void emitDistributedActorStore_transport(
     SILValue actorSelf, AbstractFunctionDecl *func,
     SILArgument *transportArg) {
   auto &B = SGF.B;
-
   auto &SGM = SGF.SGM;
   SILGenFunctionBuilder builder(SGM);
 
@@ -164,7 +135,6 @@ static void emitDistributedActorStore_transport(
   auto *var = dyn_cast<VarDecl>(vars.front());
 
   // ----
-
   auto fieldAddr = B.createRefElementAddr(
       loc, actorSelf, var,
       SGF.getLoweredType(var->getInterfaceType()));
@@ -196,7 +166,6 @@ emitDistributedActor_init_transportStore(
   SILValue transportArgValue = getActorTransportArgument(C, F, ctor);
 
   // ----
-
   auto transportFieldAddr = B.createRefElementAddr(
       loc, borrowedSelfArg.getValue(), var,
       SGF.getLoweredType(var->getInterfaceType()));
@@ -218,7 +187,6 @@ static void emitDistributedActorStore_id(
     SILValue actorSelf, AbstractFunctionDecl *func,
     SILArgument *identityArg) {
   auto &B = SGF.B;
-
   auto &SGM = SGF.SGM;
   SILGenFunctionBuilder builder(SGM);
 
@@ -269,9 +237,7 @@ static void emitDistributedActorStore_init_assignIdentity(
 
   // --- Prepare the arguments
   SILValue transportArgValue = getActorTransportArgument(C, F, ctor);
-
   ProtocolDecl *distributedActorProto = C.getProtocol(KnownProtocolKind::DistributedActor);
-
   assert(distributedActorProto);
   assert(transportProto);
 
@@ -416,7 +382,6 @@ void SILGenFunction::initializeDistributedActorImplicitStorageInit(
 
 void SILGenFunction::emitDistributedActorReady(
     ConstructorDecl *ctor, ManagedValue selfArg) {
-
   auto *dc = ctor->getDeclContext();
   auto classDecl = dc->getSelfClassDecl();
   auto &C = classDecl->getASTContext();
@@ -497,86 +462,6 @@ void SILGenFunction::emitDistributedActorReady(
 /******************* DISTRIBUTED ACTOR RESOLVE FUNCTION ***********************/
 /******************************************************************************/
 
-/// Synthesize the distributed actor's identity (`id`) initialization:
-///
-/// \verbatim
-///     transport.resolve(_, as:)
-/// \endverbatim
-static void createDistributedActorFactory_resolve(
-    SILGenFunction &SGF, ASTContext &C, FuncDecl *fd, SILValue identityValue,
-    SILValue transportValue, Type selfTy, SILValue selfMetatypeValue,
-    SILType resultTy, SILBasicBlock *normalBB, SILBasicBlock *errorBB) {
-  auto &B = SGF.B;
-  auto &SGM = SGF.SGM;
-  auto &F = SGF.F;
-  SILGenFunctionBuilder builder(SGM);
-
-  auto loc = SILLocation(fd);
-  loc.markAutoGenerated();
-
-  ProtocolDecl *distributedActorProto =
-      C.getProtocol(KnownProtocolKind::DistributedActor);
-  ProtocolDecl *transportProto =
-      C.getProtocol(KnownProtocolKind::ActorTransport);
-  assert(distributedActorProto);
-  assert(transportProto);
-
-  // // --- Open the transport existential
-  OpenedArchetypeType *Opened;
-  auto transportASTType = transportValue->getType().getASTType();
-  auto openedTransportType =
-      transportASTType->openAnyExistentialType(Opened)->getCanonicalType();
-  auto openedTransportSILType = F.getLoweredType(openedTransportType);
-  auto transportArchetypeValue =
-      B.createOpenExistentialAddr(loc, transportValue, openedTransportSILType,
-                                  OpenedExistentialAccess::Immutable);
-
-  // --- prepare the witness_method
-  // Note: it does not matter on what module we perform the lookup,
-  // it is currently ignored. So the Stdlib module is good enough.
-  auto *module = SGF.getModule().getSwiftModule();
-
-  // the conformance here is just an abstract thing so we can simplify
-  auto transportConfRef = ProtocolConformanceRef(transportProto);
-  assert(!transportConfRef.isInvalid() &&
-         "Missing conformance to `ActorTransport`");
-
-  auto distributedActorConfRef =
-      module->lookupConformance(selfTy, distributedActorProto);
-  assert(!distributedActorConfRef.isInvalid() &&
-         "Missing conformance to `DistributedActor`");
-
-  auto resolveMethod =
-      cast<FuncDecl>(transportProto->getSingleRequirement(C.Id_resolve));
-  auto resolveRef = SILDeclRef(resolveMethod, SILDeclRef::Kind::Func);
-  auto constantInfo =
-      SGF.getConstantInfo(SGF.getTypeExpansionContext(), resolveRef);
-  auto resolveSILTy = constantInfo.getSILType();
-
-  auto resolveWitnessMethod =
-      B.createWitnessMethod(loc,
-                            /*lookupTy*/ openedTransportType,
-                            /*Conformance*/ transportConfRef,
-                            /*member*/ resolveRef,
-                            /*methodTy*/ resolveSILTy);
-
-  // // --- prepare conformance subs
-  auto genericSig = resolveMethod->getGenericSignature();
-
-  SubstitutionMap subs =
-      SubstitutionMap::get(genericSig, {openedTransportType, selfTy},
-                           {transportConfRef, distributedActorConfRef});
-
-  // // ---- actually call transport.resolve(id, as: Self.self)
-
-  SmallVector<SILValue, 3> params;
-  params.push_back(identityValue);
-  params.push_back(selfMetatypeValue);
-  params.push_back(transportArchetypeValue); // self for the call, as last param
-
-  B.createTryApply(loc, resolveWitnessMethod, subs, params, normalBB, errorBB);
-}
-
 /// Function body of:
 /// \verbatim
 /// DistributedActor.resolve(
@@ -602,66 +487,28 @@ void SILGenFunction::emitDistributedActorFactory(FuncDecl *fd) {
   assert(
       transportArg->getType().getASTType()->isEqual(C.getActorTransportType()));
 
+  // --- Parameter: self
+  auto *selfTyDecl = fd->getParent()->getSelfNominalTypeDecl();
+  assert(selfTyDecl->isDistributedActor());
+
   SILValue selfArgValue = F.getSelfArgument();
   ManagedValue selfArg = ManagedValue::forUnmanaged(selfArgValue);
 
-  // type: SpecificDistributedActor.Type
-  auto selfArgType = F.mapTypeIntoContext(selfArg.getType().getASTType());
-  auto selfMetatype = getLoweredType(selfArgType);
-  SILValue selfMetatypeValue = B.createMetatype(loc, selfMetatype);
-
-  // type: SpecificDistributedActor
-  auto *selfTyDecl = fd->getParent()->getSelfNominalTypeDecl();
-  assert(selfTyDecl->isDistributedActor());
-  auto selfTy = F.mapTypeIntoContext(selfTyDecl->getDeclaredInterfaceType());
-  auto returnTy = getLoweredType(selfTy);
-
-  // ==== Prepare all the basic blocks
-  auto returnBB = createBasicBlock();
-  auto resolvedBB = createBasicBlock();
-  auto makeProxyBB = createBasicBlock();
-  auto switchBB = createBasicBlock();
-  auto errorBB = createBasicBlock();
-
-  SILFunctionConventions fnConv = F.getConventions(); // TODO: no idea?
-
-  // --- get the uninitialized allocation from the runtime system.
-  FullExpr scope(Cleanups, CleanupLocation(fd));
-
-  auto optionalReturnTy = SILType::getOptionalType(returnTy);
-
-  // ==== Call `try transport.resolve(id, as: Self.self)`
+  // ==== Case 'remote') Create the remote instance
   {
-    createDistributedActorFactory_resolve(
-        *this, C, fd, identityArg, transportArg, selfTy, selfMetatypeValue,
-        optionalReturnTy, switchBB, errorBB);
-  }
-
-  // ==== switch resolved { ... }
-  {
-    B.emitBlock(switchBB);
-    auto resolve =
-        switchBB->createPhiArgument(optionalReturnTy, OwnershipKind::Owned);
-
-    B.createSwitchEnum(
-        loc, resolve, nullptr,
-        {{C.getOptionalSomeDecl(), resolvedBB},
-         {std::make_pair(C.getOptionalNoneDecl(), makeProxyBB)}});
-  }
-
-  // ==== Case 'some') return the resolved instance
-  {
-    B.emitBlock(resolvedBB);
-
-    auto local = resolvedBB->createPhiArgument(returnTy, OwnershipKind::Owned);
-
-    B.createBranch(loc, returnBB, {local});
-  }
-
-  // ==== Case 'none') Create the remote instance
-  {
-    B.emitBlock(makeProxyBB);
     // ==== Create 'remote' distributed actor instance
+    // --- Prepare param: Self.self
+    // type: SpecificDistributedActor
+    auto returnTy = getLoweredType(
+        F.mapTypeIntoContext(selfTyDecl->getDeclaredInterfaceType()));
+
+    // type: SpecificDistributedActor.Type
+    auto selfMetatype =
+        getLoweredType(F.mapTypeIntoContext(selfArg.getType().getASTType()));
+    SILValue selfMetatypeValue = B.createMetatype(loc, selfMetatype);
+
+    // --- get the uninitialized allocation from the runtime system.
+    FullExpr scope(Cleanups, CleanupLocation(fd));
 
     // --- Call: _distributedActorRemoteInitialize(Self.self)
     auto builtinName = C.getIdentifier(
@@ -681,32 +528,8 @@ void SILGenFunction::emitDistributedActorFactory(FuncDecl *fd) {
     emitDistributedActorStore_transport(
         C, *this, /*actorSelf*/remote, fd, transportArg);
 
-    // ==== Branch to return the fully initialized remote instance
-    B.createBranch(loc, returnBB, {remote});
-  }
-
-  // --- Emit return logic
-  // return <remote>
-  {
-    B.emitBlock(returnBB);
-
-    auto local = returnBB->createPhiArgument(returnTy, OwnershipKind::Owned);
-
-    Cleanups.emitCleanupsForReturn(CleanupLocation(loc), NotForUnwind);
-    B.createReturn(loc, local);
-  }
-
-  // --- Emit rethrow logic
-  // throw error
-  {
-    B.emitBlock(errorBB);
-
-    auto error = errorBB->createPhiArgument(
-        fnConv.getSILErrorType(F.getTypeExpansionContext()),
-        OwnershipKind::Owned);
-
-    Cleanups.emitCleanupsForReturn(CleanupLocation(loc), IsForUnwind);
-    B.createThrow(loc, error);
+    // ==== Return the fully initialized remote instance
+    B.createReturn(loc, remote);
   }
 }
 
@@ -740,8 +563,9 @@ void SILGenFunction::emitDistributedActor_resignAddress(
                              getLoweredType(idVarDeclRef->getType()));
 
   // ==== locate: self.actorTransport
-  auto transportVarDeclRef = lookupActorTransportProperty(ctx, cd, selfValue);
-
+  auto transportVarDeclRefs = cd->lookupDirect(ctx.Id_actorTransport);
+  assert(transportVarDeclRefs.size() == 1);
+  auto *transportVarDeclRef = dyn_cast<VarDecl>(transportVarDeclRefs.front());
   auto transportRef =
       B.createRefElementAddr(Loc, selfValue, transportVarDeclRef,
                              getLoweredType(transportVarDeclRef->getType()));