Merge pull request #7074 from apple/dl/lldb-add-foundation._nsswifttimezone-support

[lldb] Add Foundation._NSSwiftTimeZone support

Author: adrian-prantl

lldb/include/lldb/Target/LanguageRuntime.h

@@ -67,6 +67,12 @@ class LanguageRuntime : public Runtime, public PluginInterface {
 
   virtual lldb::LanguageType GetLanguageType() const = 0;
 
+  /// Return the preferred language runtime instance, which in most cases will
+  /// be the current instance.
+  virtual LanguageRuntime *GetPreferredLanguageRuntime(ValueObject &in_value) {
+    return nullptr;
+  }
+
   virtual bool GetObjectDescription(Stream &str, ValueObject &object) = 0;
 
   virtual bool GetObjectDescription(Stream &str, Value &value,

lldb/source/Core/ValueObjectDynamicValue.cpp

@@ -181,7 +181,18 @@ bool ValueObjectDynamicValue::UpdateValue() {
       known_type != lldb::eLanguageTypeUnknown &&
       known_type != lldb::eLanguageTypeC) {
     runtime = process->GetLanguageRuntime(known_type);
-    if (runtime)
+    if (auto *preferred_runtime =
+            runtime->GetPreferredLanguageRuntime(*m_parent)) {
+      // Try the preferred runtime first.
+      found_dynamic_type = preferred_runtime->GetDynamicTypeAndAddress(
+          *m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
+          value_type);
+      if (found_dynamic_type)
+        // Set the operative `runtime` for later use in this function.
+        runtime = preferred_runtime;
+    }
+    if (!found_dynamic_type)
+      // Fallback to the runtime for `known_type`.
       found_dynamic_type = runtime->GetDynamicTypeAndAddress(
           *m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
           value_type);

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

@@ -132,6 +132,20 @@ bool lldb_private::formatters::NSTimeZoneSummaryProvider(
       stream.Printf("%s", summary_stream.GetData());
       return true;
     }
+  } else if (class_name == "_NSSwiftTimeZone") {
+    llvm::ArrayRef<ConstString> identifier_path = {
+        ConstString("timeZone"),
+        ConstString("_timeZone"),
+        ConstString("some"),
+        ConstString("identifier"),
+    };
+    if (auto identifier_sp = valobj.GetChildAtNamePath(identifier_path)) {
+      std::string desc;
+      if (identifier_sp->GetSummaryAsCString(desc, options)) {
+        stream.PutCString(desc);
+        return true;
+      }
+    }
   }
 
   return false;

lldb/source/Plugins/Language/Swift/SwiftLanguage.cpp

@@ -636,6 +636,11 @@ LoadFoundationValueTypesFormatters(lldb::TypeCategoryImplSP swift_category_sp) {
       "Decimal summary provider", ConstString("Foundation.Decimal"),
       TypeSummaryImpl::Flags(summary_flags).SetDontShowChildren(true));
 
+  lldb_private::formatters::AddCXXSummary(
+      swift_category_sp, lldb_private::formatters::NSTimeZoneSummaryProvider,
+      "NSTimeZone summary provider", ConstString("Foundation._NSSwiftTimeZone"),
+      TypeSummaryImpl::Flags(summary_flags).SetDontShowChildren(true));
+
   lldb_private::formatters::AddCXXSynthetic(
       swift_category_sp,
       lldb_private::formatters::swift::URLComponentsSyntheticFrontEndCreator,

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp

@@ -10,8 +10,10 @@
 
 #include "lldb/Expression/FunctionCaller.h"
 #include "lldb/Target/ABI.h"
+#include "lldb/Target/Language.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
+#include "lldb/lldb-enumerations.h"
 
 using namespace lldb;
 using namespace lldb_private;
@@ -668,6 +670,19 @@ uint64_t ClassDescriptorV2::GetInstanceSize() {
   return 0;
 }
 
+// From the ObjC runtime.
+static uint8_t IS_SWIFT_STABLE = 1U << 1;
+
+LanguageType ClassDescriptorV2::GetImplementationLanguage() const {
+  std::unique_ptr<objc_class_t> objc_class;
+  if (auto *process = m_runtime.GetProcess())
+    if (Read_objc_class(process, objc_class))
+      if (objc_class->m_flags & IS_SWIFT_STABLE)
+        return lldb::eLanguageTypeSwift;
+
+  return lldb::eLanguageTypeObjC;
+}
+
 ClassDescriptorV2::iVarsStorage::iVarsStorage() : m_ivars(), m_mutex() {}
 
 size_t ClassDescriptorV2::iVarsStorage::size() { return m_ivars.size(); }

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.h

@@ -12,6 +12,7 @@
 #include <mutex>
 
 #include "AppleObjCRuntimeV2.h"
+#include "lldb/lldb-enumerations.h"
 #include "lldb/lldb-private.h"
 
 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
@@ -34,6 +35,8 @@ class ClassDescriptorV2 : public ObjCLanguageRuntime::ClassDescriptor {
     return true; // any Objective-C v2 runtime class descriptor we vend is valid
   }
 
+  lldb::LanguageType GetImplementationLanguage() const override;
+
   // a custom descriptor is used for tagged pointers
   bool GetTaggedPointerInfo(uint64_t *info_bits = nullptr,
                             uint64_t *value_bits = nullptr,

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

@@ -33,6 +33,7 @@
 #include "lldb/Target/ABI.h"
 #include "lldb/Target/DynamicLoader.h"
 #include "lldb/Target/ExecutionContext.h"
+#include "lldb/Target/LanguageRuntime.h"
 #include "lldb/Target/Platform.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/RegisterContext.h"
@@ -758,6 +759,19 @@ AppleObjCRuntimeV2::AppleObjCRuntimeV2(Process *process,
   RegisterObjCExceptionRecognizer(process);
 }
 
+LanguageRuntime *
+AppleObjCRuntimeV2::GetPreferredLanguageRuntime(ValueObject &in_value) {
+  if (auto process_sp = in_value.GetProcessSP()) {
+    assert(process_sp.get() == m_process);
+    if (auto descriptor_sp = GetNonKVOClassDescriptor(in_value)) {
+      LanguageType impl_lang = descriptor_sp->GetImplementationLanguage();
+      if (impl_lang != eLanguageTypeUnknown)
+        return process_sp->GetLanguageRuntime(impl_lang);
+    }
+  }
+  return nullptr;
+}
+
 bool AppleObjCRuntimeV2::GetDynamicTypeAndAddress(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h

@@ -37,6 +37,8 @@ class AppleObjCRuntimeV2 : public AppleObjCRuntime {
 
   static llvm::StringRef GetPluginNameStatic() { return "apple-objc-v2"; }
 
+  LanguageRuntime *GetPreferredLanguageRuntime(ValueObject &in_value) override;
+
   static char ID;
 
   bool isA(const void *ClassID) const override {

lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h

@@ -23,6 +23,7 @@
 #include "lldb/Symbol/Type.h"
 #include "lldb/Target/LanguageRuntime.h"
 #include "lldb/Utility/ConstString.h"
+#include "lldb/lldb-enumerations.h"
 #include "lldb/lldb-private.h"
 
 class CommandObjectObjC_ClassTable_Dump;
@@ -84,6 +85,11 @@ class ObjCLanguageRuntime : public LanguageRuntime {
       return (m_is_cf == eLazyBoolYes);
     }
 
+    /// Determine whether this class is implemented in Swift.
+    virtual lldb::LanguageType GetImplementationLanguage() const {
+      return lldb::eLanguageTypeObjC;
+    }
+
     virtual bool IsValid() = 0;
 
     /// There are two routines in the ObjC runtime that tagged pointer clients

lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntimeDynamicTypeResolution.cpp

@@ -22,6 +22,7 @@
 #include "lldb/Symbol/Variable.h"
 #include "lldb/Symbol/VariableList.h"
 #include "lldb/Target/ProcessStructReader.h"
+#include "lldb/Target/SectionLoadList.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
@@ -39,6 +40,7 @@
 #include "swift/Remote/MemoryReader.h"
 #include "swift/RemoteAST/RemoteAST.h"
 #include "swift/Runtime/Metadata.h"
+#include "swift/Strings.h"
 
 #include <sstream>
 
@@ -2941,6 +2943,80 @@ SwiftLanguageRuntimeImpl::GetValueType(ValueObject &in_value,
   return Value::ValueType::Scalar;
 }
 
+namespace {
+struct SwiftNominalType {
+  std::string module;
+  std::string identifier;
+};
+
+// Find the Swift class that backs an ObjC type.
+//
+// A Swift class that uses the @objc(<ClassName>) attribute will emit ObjC
+// metadata into the binary. Typically, ObjC classes have a symbol in the form
+// of OBJC_CLASS_$_<ClassName>, however for Swift classes, there are two symbols
+// that both point to the ObjC class metadata, where the second symbol is a
+// Swift mangled name.
+std::optional<SwiftNominalType> GetSwiftClass(ValueObject &valobj,
+                                              AppleObjCRuntime &objc_runtime) {
+  // To find the Swift symbol, the following preparation steps are taken:
+  //   1. Get the value's ISA pointer
+  //   2. Resolve the ISA load address into an Address instance
+  //   3. Get the Module that contains the Address
+  auto descriptor_sp = objc_runtime.GetClassDescriptor(valobj);
+  if (!descriptor_sp)
+    return {};
+
+  auto isa_load_addr = descriptor_sp->GetISA();
+  Address isa;
+  const auto &sections = objc_runtime.GetTargetRef().GetSectionLoadList();
+  if (!sections.ResolveLoadAddress(isa_load_addr, isa))
+    return {};
+
+  // Next, iterate over the Module's symbol table, looking for a symbol with
+  // following criteria:
+  //   1. The symbol address is the ISA address
+  //   2. The symbol name is a Swift mangled name
+  std::optional<StringRef> swift_symbol;
+  auto find_swift_symbol_for_isa = [&](Symbol *symbol) {
+    if (symbol->GetAddress() == isa) {
+      StringRef symbol_name =
+          symbol->GetMangled().GetMangledName().GetStringRef();
+      if (SwiftLanguageRuntime::IsSwiftMangledName(symbol_name)) {
+        swift_symbol = symbol_name;
+        return false;
+      }
+    }
+    return true;
+  };
+
+  isa.GetModule()->GetSymtab()->ForEachSymbolContainingFileAddress(
+      isa.GetFileAddress(), find_swift_symbol_for_isa);
+  if (!swift_symbol)
+    return {};
+
+  // Once the Swift symbol is found, demangle it into a node tree. The node tree
+  // provides the final data, the name of the class and the name of its module.
+  swift::Demangle::Context ctx;
+  auto *global = ctx.demangleSymbolAsNode(*swift_symbol);
+  using Kind = Node::Kind;
+  auto *class_node = swift_demangle::nodeAtPath(
+      global, {Kind::TypeMetadata, Kind::Type, Kind::Class});
+  if (class_node && class_node->getNumChildren() == 2) {
+    auto module_node = class_node->getFirstChild();
+    auto ident_node = class_node->getLastChild();
+    if (module_node->getKind() == Kind::Module && module_node->hasText() &&
+        ident_node->getKind() == Kind::Identifier && ident_node->hasText()) {
+      auto module_name = module_node->getText();
+      auto class_name = ident_node->getText();
+      return SwiftNominalType{module_name.str(), class_name.str()};
+    }
+  }
+
+  return {};
+}
+
+} // namespace
+
 bool SwiftLanguageRuntimeImpl::GetDynamicTypeAndAddress_ClangType(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,
@@ -2967,9 +3043,22 @@ bool SwiftLanguageRuntimeImpl::GetDynamicTypeAndAddress_ClangType(
       dyn_name.startswith("__NS"))
     return false;
 
+  SwiftNominalType swift_class;
+
+  if (auto maybe_swift_class = GetSwiftClass(in_value, *objc_runtime)) {
+    swift_class = *maybe_swift_class;
+    std::string type_name =
+        (llvm::Twine(swift_class.module) + "." + swift_class.identifier).str();
+    dyn_class_type_or_name.SetName(type_name.data());
+    address.SetRawAddress(in_value.GetPointerValue());
+  } else {
+    swift_class.module = swift::MANGLING_MODULE_OBJC;
+    swift_class.identifier = dyn_name;
+  }
+
   std::string remangled;
   {
-    // Create a mangle tree for __C.dyn_name?.
+    // Create a mangle tree for Swift.Optional<$module.$class>
     using namespace swift::Demangle;
     NodeFactory factory;
     NodePointer global = factory.createNode(Node::Kind::Global);
@@ -2980,7 +3069,8 @@ bool SwiftLanguageRuntimeImpl::GetDynamicTypeAndAddress_ClangType(
     NodePointer ety = factory.createNode(Node::Kind::Type);
     bge->addChild(ety, factory);
     NodePointer e = factory.createNode(Node::Kind::Enum);
-    e->addChild(factory.createNode(Node::Kind::Module, "Swift"), factory);
+    e->addChild(factory.createNode(Node::Kind::Module, swift::STDLIB_NAME),
+                factory);
     e->addChild(factory.createNode(Node::Kind::Identifier, "Optional"),
                 factory);
     ety->addChild(e, factory);
@@ -2989,8 +3079,11 @@ bool SwiftLanguageRuntimeImpl::GetDynamicTypeAndAddress_ClangType(
     NodePointer cty = factory.createNode(Node::Kind::Type);
     list->addChild(cty, factory);
     NodePointer c = factory.createNode(Node::Kind::Class);
-    c->addChild(factory.createNode(Node::Kind::Module, "__C"), factory);
-    c->addChild(factory.createNode(Node::Kind::Identifier, dyn_name), factory);
+    c->addChild(factory.createNode(Node::Kind::Module, swift_class.module),
+                factory);
+    c->addChild(
+        factory.createNode(Node::Kind::Identifier, swift_class.identifier),
+        factory);
     cty->addChild(c, factory);
 
     auto mangling = mangleNode(global);