Merge pull request swiftlang#68996 from aschwaighofer/objective_c_protocol_symbolic_ref

aschwaighofer · web-flow · commit e4fbde80639b · 2023-10-07T09:18:33.000-07:00
Add support for objective c protocol symbolic references
diff --git a/docs/ABI/Mangling.rst b/docs/ABI/Mangling.rst
@@ -108,6 +108,10 @@ The following symbolic reference kinds are currently implemented:
      symbolic-extended-existential-type-shape ::= '\x0B' .{4} // Reference points directly to a NonUniqueExtendedExistentialTypeShape
    #endif
 
+   #if SWIFT_RUNTIME_VERSION >= 5.TBD
+    objective-c-protocol-relative-reference  ::=  `\x0C`  .{4} // Reference points directly to a objective-c protcol reference
+   #endif
+
 A mangled name may also include ``\xFF`` bytes, which are only used for
 alignment padding. They do not affect what the mangled name references and can
 be skipped over and ignored.
diff --git a/include/swift/AST/ASTContext.h b/include/swift/AST/ASTContext.h
@@ -944,6 +944,10 @@ class ASTContext final {
   /// that fixes up the value witness table of @_rawLayout dependent types.
   AvailabilityContext getInitRawStructMetadataAvailability();
 
+  /// Get the runtime availability of being able to use symbolic references to
+  /// objective c protocols.
+  AvailabilityContext getObjCSymbolicReferencesAvailability();
+
   /// Get the runtime availability of features introduced in the Swift 5.2
   /// compiler for the target platform.
   AvailabilityContext getSwift52Availability();
diff --git a/include/swift/AST/IRGenOptions.h b/include/swift/AST/IRGenOptions.h
@@ -408,6 +408,8 @@ class IRGenOptions {
   /// Enable runtime instantiation of value witness strings for generic types
   unsigned EnableLayoutStringValueWitnessesInstantiation : 1;
 
+  unsigned EnableObjectiveCProtocolSymbolicReferences : 1;
+
   /// Instrument code to generate profiling information.
   unsigned GenerateProfile : 1;
 
@@ -527,6 +529,7 @@ class IRGenOptions {
         UseTypeLayoutValueHandling(true), ForceStructTypeLayouts(false),
         EnableLayoutStringValueWitnesses(false),
         EnableLayoutStringValueWitnessesInstantiation(false),
+        EnableObjectiveCProtocolSymbolicReferences(false),
         GenerateProfile(false), EnableDynamicReplacementChaining(false),
         DisableDebuggerShadowCopies(false),
         DisableConcreteTypeMetadataMangledNameAccessors(false),
diff --git a/include/swift/Demangling/DemangleNodes.def b/include/swift/Demangling/DemangleNodes.def
@@ -371,5 +371,8 @@ NODE(OpaqueReturnTypeParent)
 // Added in Swift 5.9 + 1
 NODE(AsyncRemoved)
 
+// Added in Swift 5.TBD
+NODE(ObjectiveCProtocolSymbolicReference)
+
 #undef CONTEXT_NODE
 #undef NODE
diff --git a/include/swift/Demangling/Demangler.h b/include/swift/Demangling/Demangler.h
@@ -383,6 +383,8 @@ enum class SymbolicReferenceKind : uint8_t {
   UniqueExtendedExistentialTypeShape,
   /// A symbolic reference to a non-unique extended existential type shape.
   NonUniqueExtendedExistentialTypeShape,
+  /// A symbolic reference to a objective C protocol ref.
+  ObjectiveCProtocol,
 };
 
 using SymbolicReferenceResolver_t = NodePointer (SymbolicReferenceKind,
diff --git a/include/swift/Demangling/TypeDecoder.h b/include/swift/Demangling/TypeDecoder.h
@@ -754,6 +754,7 @@ class TypeDecoder {
     case NodeKind::ConstrainedExistentialSelf:
       return Builder.createGenericTypeParameterType(/*depth*/ 0, /*index*/ 0);
 
+    case NodeKind::ObjectiveCProtocolSymbolicReference:
     case NodeKind::Protocol:
     case NodeKind::ProtocolSymbolicReference: {
       if (auto Proto = decodeMangledProtocolType(Node, depth + 1)) {
@@ -1574,8 +1575,9 @@ class TypeDecoder {
     if (node->getKind() == NodeKind::Type)
       return decodeMangledProtocolType(node->getChild(0), depth + 1);
 
-    if ((node->getNumChildren() < 2 || node->getKind() != NodeKind::Protocol)
-        && node->getKind() != NodeKind::ProtocolSymbolicReference)
+    if ((node->getNumChildren() < 2 || node->getKind() != NodeKind::Protocol) &&
+        node->getKind() != NodeKind::ProtocolSymbolicReference &&
+        node->getKind() != NodeKind::ObjectiveCProtocolSymbolicReference)
       return BuiltProtocolDecl();
 
 #if SWIFT_OBJC_INTEROP
diff --git a/include/swift/Option/FrontendOptions.td b/include/swift/Option/FrontendOptions.td
@@ -1242,6 +1242,13 @@ def disable_new_llvm_pass_manager :
   Flag<["-"], "disable-new-llvm-pass-manager">,
   HelpText<"Disable the new llvm pass manager">;
 
+def enable_objective_c_protocol_symbolic_references :
+  Flag<["-"], "enable-objective-c-protocol-symbolic-references">,
+  HelpText<"Enable objective-c protocol symbolic references">;
+def disable_objective_c_protocol_symbolic_references :
+  Flag<["-"], "disable-objective-c-protocol-symbolic-references">,
+  HelpText<"Disable objective-c protocol symbolic references">;
+
 def disable_emit_generic_class_ro_t_list :
   Flag<["-"], "disable-emit-generic-class-ro_t-list">,
   HelpText<"Disable emission of a section with references to class_ro_t of "
diff --git a/include/swift/Remote/MetadataReader.h b/include/swift/Remote/MetadataReader.h
@@ -512,6 +512,33 @@ class MetadataReader {
                           Node::Kind::NonUniqueExtendedExistentialTypeShapeSymbolicReference,
                           resolved.getResolvedAddress().getAddressData());
       }
+      case Demangle::SymbolicReferenceKind::ObjectiveCProtocol: {
+        // 'resolved' points to a struct of two relative addresses.
+        // The second entry is a relative address to the mangled protocol
+        // without symbolic references.
+        auto addr =
+            resolved.getResolvedAddress().getAddressData() + sizeof(int32_t);
+        int32_t offset;
+        Reader->readInteger(RemoteAddress(addr), &offset);
+        auto addrOfTypeRef = addr + offset;
+        resolved = Reader->getSymbol(RemoteAddress(addrOfTypeRef));
+
+        // Dig out the protocol from the protocol list.
+        auto protocolList = readMangledName(resolved.getResolvedAddress(),
+                                            MangledNameKind::Type, dem);
+        assert(protocolList->getFirstChild()
+                   ->getFirstChild()
+                   ->getFirstChild()
+                   ->getFirstChild()
+                   ->getKind() == Node::Kind::Protocol);
+        auto protocol = protocolList->getFirstChild()
+                            ->getFirstChild()
+                            ->getFirstChild()
+                            ->getFirstChild();
+        auto protocolType = dem.createNode(Node::Kind::Type);
+        protocolType->addChild(protocol, dem);
+        return protocolType;
+      }
       }
 
       return nullptr;
diff --git a/lib/AST/Availability.cpp b/lib/AST/Availability.cpp
@@ -585,6 +585,10 @@ ASTContext::getInitRawStructMetadataAvailability() {
   return getSwiftFutureAvailability();
 }
 
+AvailabilityContext ASTContext::getObjCSymbolicReferencesAvailability() {
+  return getSwiftFutureAvailability();
+}
+
 AvailabilityContext ASTContext::getSwift52Availability() {
   auto target = LangOpts.Target;
 
diff --git a/lib/Demangling/Demangler.cpp b/lib/Demangling/Demangler.cpp
@@ -45,6 +45,7 @@ static bool isDeclName(Node::Kind kind) {
     case Node::Kind::InfixOperator:
     case Node::Kind::TypeSymbolicReference:
     case Node::Kind::ProtocolSymbolicReference:
+    case Node::Kind::ObjectiveCProtocolSymbolicReference:
       return true;
     default:
       return false;
@@ -58,6 +59,7 @@ static bool isAnyGeneric(Node::Kind kind) {
     case Node::Kind::Enum:
     case Node::Kind::Protocol:
     case Node::Kind::ProtocolSymbolicReference:
+    case Node::Kind::ObjectiveCProtocolSymbolicReference:
     case Node::Kind::OtherNominalType:
     case Node::Kind::TypeAlias:
     case Node::Kind::TypeSymbolicReference:
@@ -278,6 +280,7 @@ static bool isProtocolNode(Demangle::NodePointer Node) {
     return isProtocolNode(Node->getChild(0));
   case Demangle::Node::Kind::Protocol:
   case Demangle::Node::Kind::ProtocolSymbolicReference:
+  case Demangle::Node::Kind::ObjectiveCProtocolSymbolicReference:
     return true;
   default:
     return false;
@@ -870,6 +873,10 @@ NodePointer Demangler::demangleSymbolicReference(unsigned char rawKind) {
     kind = SymbolicReferenceKind::NonUniqueExtendedExistentialTypeShape;
     direct = Directness::Direct;
     break;
+  case 0x0c:
+    kind = SymbolicReferenceKind::ObjectiveCProtocol;
+    direct = Directness::Direct;
+    break;
   // These are all currently reserved but unused.
   case 0x03: // direct to protocol conformance descriptor
   case 0x04: // indirect to protocol conformance descriptor
@@ -893,8 +900,10 @@ NodePointer Demangler::demangleSymbolicReference(unsigned char rawKind) {
   
   // Types register as substitutions even when symbolically referenced.
   // OOPS: Except for opaque type references!
-  if (kind == SymbolicReferenceKind::Context &&
-      resolved->getKind() != Node::Kind::OpaqueTypeDescriptorSymbolicReference &&
+  if ((kind == SymbolicReferenceKind::Context ||
+       kind == SymbolicReferenceKind::ObjectiveCProtocol) &&
+      resolved->getKind() !=
+          Node::Kind::OpaqueTypeDescriptorSymbolicReference &&
       resolved->getKind() != Node::Kind::OpaqueReturnTypeOf)
     addSubstitution(resolved);
   return resolved;
@@ -1753,6 +1762,9 @@ NodePointer Demangler::popProtocol() {
   
   if (NodePointer SymbolicRef = popNode(Node::Kind::ProtocolSymbolicReference)){
     return SymbolicRef;
+  } else if (NodePointer SymbolicRef =
+                 popNode(Node::Kind::ObjectiveCProtocolSymbolicReference)) {
+    return SymbolicRef;
   }
 
   NodePointer Name = popNode(isDeclName);
@@ -2584,6 +2596,8 @@ NodePointer Demangler::popAssocTypeName() {
   // If we haven't seen a protocol, check for a symbolic reference.
   if (!Proto)
     Proto = popNode(Node::Kind::ProtocolSymbolicReference);
+  if (!Proto)
+    Proto = popNode(Node::Kind::ObjectiveCProtocolSymbolicReference);
 
   NodePointer Id = popNode(Node::Kind::Identifier);
   NodePointer AssocTy = createWithChild(Node::Kind::DependentAssociatedTypeRef, Id);
diff --git a/lib/Demangling/NodePrinter.cpp b/lib/Demangling/NodePrinter.cpp
@@ -626,6 +626,7 @@ class NodePrinter {
     case Node::Kind::NonUniqueExtendedExistentialTypeShapeSymbolicReference:
     case Node::Kind::SymbolicExtendedExistentialType:
     case Node::Kind::HasSymbolQuery:
+    case Node::Kind::ObjectiveCProtocolSymbolicReference:
       return false;
     }
     printer_unreachable("bad node kind");
@@ -3193,6 +3194,10 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     Printer << "non-unique existential shape symbolic reference 0x";
     Printer.writeHex(Node->getIndex());
     return nullptr;
+  case Node::Kind::ObjectiveCProtocolSymbolicReference:
+    Printer << "objective-c protocol symbolic reference 0x";
+    Printer.writeHex(Node->getIndex());
+    return nullptr;
   case Node::Kind::SymbolicExtendedExistentialType: {
     auto shape = Node->getChild(0);
     bool isUnique =
diff --git a/lib/Demangling/OldRemangler.cpp b/lib/Demangling/OldRemangler.cpp
@@ -2876,6 +2876,12 @@ mangleNonUniqueExtendedExistentialTypeShapeSymbolicReference(Node *node,
                                                      unsigned int depth) {
   return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
 }
+ManglingError
+Remangler::mangleObjectiveCProtocolSymbolicReference(Node *node,
+                                                     unsigned int depth) {
+  return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
+}
+
 ManglingError
 Remangler::mangleCanonicalSpecializedGenericMetaclass(Node *node,
                                                       unsigned depth) {
diff --git a/lib/Demangling/Remangler.cpp b/lib/Demangling/Remangler.cpp
@@ -3474,6 +3474,14 @@ ManglingError Remangler::mangleTypeSymbolicReference(Node *node,
       depth + 1);
 }
 
+ManglingError
+Remangler::mangleObjectiveCProtocolSymbolicReference(Node *node,
+                                                     unsigned depth) {
+  return mangle(Resolver(SymbolicReferenceKind::ObjectiveCProtocol,
+                         (const void *)node->getIndex()),
+                depth + 1);
+}
+
 ManglingError Remangler::mangleProtocolSymbolicReference(Node *node,
                                                          unsigned depth) {
   return mangle(
@@ -3710,7 +3718,6 @@ mangleNonUniqueExtendedExistentialTypeShapeSymbolicReference(Node *node,
   // We don't support absolute references in the mangling of these
   return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
 }
-
 } // anonymous namespace
 
 /// The top-level interface to the remangler.
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
@@ -2932,6 +2932,11 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     return true;
   }
 
+  Opts.EnableObjectiveCProtocolSymbolicReferences =
+    Args.hasFlag(OPT_enable_objective_c_protocol_symbolic_references,
+                 OPT_disable_objective_c_protocol_symbolic_references,
+                 Opts.EnableObjectiveCProtocolSymbolicReferences);
+
   if (const Arg *A = Args.getLastArg(options::OPT_platform_c_calling_convention)) {
     Opts.PlatformCCallingConvention =
       llvm::StringSwitch<llvm::CallingConv::ID>(A->getValue())
diff --git a/lib/IRGen/GenObjC.cpp b/lib/IRGen/GenObjC.cpp
@@ -397,6 +397,42 @@ IRGenModule::getObjCProtocolGlobalVars(ProtocolDecl *proto) {
   return pair;
 }
 
+llvm::Constant *
+IRGenModule::getObjCProtocolRefSymRefDescriptor(ProtocolDecl *protocol) {
+  // See whether we already emitted this protocol reference.
+  auto found = ObjCProtocolSymRefs.find(protocol);
+  if (found != ObjCProtocolSymRefs.end()) {
+    return found->second;
+  }
+
+  ConstantInitBuilder InitBuilder(*this);
+  ConstantStructBuilder B(InitBuilder.beginStruct());
+  B.setPacked(true);
+  auto protocolRef = getAddrOfObjCProtocolRef(protocol, NotForDefinition);
+  B.addRelativeAddress(cast<llvm::Constant>(protocolRef.getAddress()));
+  auto ty = protocol->getDeclaredType()->getCanonicalType();
+  auto typeRef =
+      getTypeRef(ty, CanGenericSignature(), MangledTypeRefRole::FlatUnique)
+          .first;
+  B.addRelativeAddress(typeRef);
+  auto future = B.finishAndCreateFuture();
+
+  llvm::SmallString<64> nameBuffer;
+  StringRef protocolName = protocol->getObjCRuntimeName(nameBuffer);
+  auto *protocolSymRef = new llvm::GlobalVariable(
+      Module, future.getType(), /*constant*/ true,
+      llvm::GlobalValue::LinkOnceAnyLinkage, nullptr,
+      llvm::Twine("\01l_OBJC_PROTOCOL_SYMREF_$_") + protocolName);
+  future.installInGlobal(protocolSymRef);
+  protocolSymRef->setAlignment(
+      llvm::MaybeAlign(getPointerAlignment().getValue()));
+  protocolSymRef->setVisibility(llvm::GlobalValue::HiddenVisibility);
+
+  ObjCProtocolSymRefs.insert({protocol, protocolSymRef});
+
+  return protocolSymRef;
+}
+
 static std::pair<uint64_t, llvm::ConstantArray *>
 getProtocolRefsList(llvm::Constant *protocol) {
   // We expect to see a structure like this.
diff --git a/lib/IRGen/IRGenMangler.cpp b/lib/IRGen/IRGenMangler.cpp
@@ -110,7 +110,7 @@ IRGenMangler::withSymbolicReferences(IRGenModule &IGM,
       // TODO: We could assign a symbolic reference discriminator to refer
       // to objc protocol refs.
       if (auto proto = dyn_cast<ProtocolDecl>(type)) {
-        if (proto->isObjC()) {
+        if (proto->isObjC() && !IGM.canUseObjCSymbolicReferences()) {
           return false;
         }
       }
diff --git a/lib/IRGen/IRGenModule.cpp b/lib/IRGen/IRGenModule.cpp
@@ -1944,6 +1944,16 @@ bool IRGenModule::shouldPrespecializeGenericMetadata() {
          canPrespecializeTarget;
 }
 
+bool IRGenModule::canUseObjCSymbolicReferences() {
+  if (!IRGen.Opts.EnableObjectiveCProtocolSymbolicReferences)
+    return false;
+  auto &context = getSwiftModule()->getASTContext();
+  auto deploymentAvailability =
+      AvailabilityContext::forDeploymentTarget(context);
+  return deploymentAvailability.isContainedIn(
+      context.getObjCSymbolicReferencesAvailability());
+}
+
 bool IRGenModule::canMakeStaticObjectsReadOnly() {
   // Unconditionally disable this until we can fix the metadata.
   // The trick of using the Empty array metadata for static arrays
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
@@ -922,7 +922,9 @@ class IRGenModule {
   bool shouldPrespecializeGenericMetadata();
   
   bool canMakeStaticObjectsReadOnly();
-  
+
+  bool canUseObjCSymbolicReferences();
+
   Size getAtomicBoolSize() const { return AtomicBoolSize; }
   Alignment getAtomicBoolAlignment() const { return AtomicBoolAlign; }
 
@@ -1283,6 +1285,7 @@ class IRGenModule {
   };
 
   llvm::DenseMap<ProtocolDecl*, ObjCProtocolPair> ObjCProtocols;
+  llvm::DenseMap<ProtocolDecl *, llvm::Constant *> ObjCProtocolSymRefs;
   llvm::SmallVector<ProtocolDecl*, 4> LazyObjCProtocolDefinitions;
   llvm::DenseMap<KeyPathPattern*, llvm::GlobalVariable*> KeyPathPatterns;
 
@@ -1306,6 +1309,7 @@ class IRGenModule {
   SuccessorMap<unsigned, llvm::Function*> EmittedFunctionsByOrder;
 
   ObjCProtocolPair getObjCProtocolGlobalVars(ProtocolDecl *proto);
+  llvm::Constant *getObjCProtocolRefSymRefDescriptor(ProtocolDecl *protocol);
   void emitLazyObjCProtocolDefinitions();
   void emitLazyObjCProtocolDefinition(ProtocolDecl *proto);
 
diff --git a/lib/IRGen/MetadataRequest.cpp b/lib/IRGen/MetadataRequest.cpp
@@ -404,11 +404,20 @@ llvm::Constant *IRGenModule::getAddrOfStringForTypeRef(
     switch (referent.getKind()) {
     case SymbolicReferent::NominalType: {
       auto type = const_cast<NominalTypeDecl*>(referent.getNominalType());
+      bool isObjCProtocol = false;
       if (auto proto = dyn_cast<ProtocolDecl>(type)) {
-        // The symbolic reference is to the protocol descriptor of the
-        // referenced protocol.
-        ref = getAddrOfLLVMVariableOrGOTEquivalent(
-          LinkEntity::forProtocolDescriptor(proto));
+        if (proto->isObjC()) {
+          assert(canUseObjCSymbolicReferences());
+          ref = ConstantReference(
+              cast<llvm::Constant>(getObjCProtocolRefSymRefDescriptor(proto)),
+              ConstantReference::Direct);
+          isObjCProtocol = true;
+        } else {
+          // The symbolic reference is to the protocol descriptor of the
+          // referenced protocol.
+          ref = getAddrOfLLVMVariableOrGOTEquivalent(
+              LinkEntity::forProtocolDescriptor(proto));
+        }
       } else {
         // The symbolic reference is to the type context descriptor of the
         // referenced type.
@@ -417,7 +426,7 @@ llvm::Constant *IRGenModule::getAddrOfStringForTypeRef(
           LinkEntity::forNominalTypeDescriptor(type));
       }
       // \1 - direct reference, \2 - indirect reference
-      kind = (ref.isIndirect() ? 0x02 : 0x01);
+      kind = (ref.isIndirect() ? 0x02 : (isObjCProtocol ? 0x0c : 0x01));
       break;
     }
     case SymbolicReferent::OpaqueType: {
diff --git a/stdlib/public/runtime/MetadataLookup.cpp b/stdlib/public/runtime/MetadataLookup.cpp
diff --git a/test/IRGen/objc_protocol_symbolic_reference.swift b/test/IRGen/objc_protocol_symbolic_reference.swift
diff --git a/test/Interpreter/objc_protocol_symbolic_reference.swift b/test/Interpreter/objc_protocol_symbolic_reference.swift
diff --git a/test/Reflection/typeref_decoding_objc.swift b/test/Reflection/typeref_decoding_objc.swift

Original file line number	Diff line number	Diff line change
`@@ -585,6 +585,10 @@ ASTContext::getInitRawStructMetadataAvailability() {`
`585`	`585`	`return getSwiftFutureAvailability();`
`586`	`586`	`}`
`587`	`587`
	`588`	`+AvailabilityContext ASTContext::getObjCSymbolicReferencesAvailability() {`
	`589`	`+ return getSwiftFutureAvailability();`
	`590`	`+}`
	`591`	`+`
`588`	`592`	`AvailabilityContext ASTContext::getSwift52Availability() {`
`589`	`593`	`auto target = LangOpts.Target;`
`590`	`594`