Add llvm-style RTTI to ObjectFile hierarchy

[labath]

Summary

On the heels of D62934, this patch uses the same approach to introduce
llvm RTTI support to the ObjectFile hierarchy. It also replaces the
existing uses of GetPluginName doing run-time type checks with
llvm::dyn_cast and friends.

This formally introduces new dependencies from some other plugins to
ObjectFile plugins. However, I believe this is fine because:

• these dependencies were already kind of there, and the only reason we could get away with not modeling them explicitly was because the code was relying on magically knowing what will GetPluginName() return for a particular kind of object files.
• the dependencies themselves are logical (it makes sense for SymbolVendorELF to depend on ObjectFileELF), or at least don't actively get in the way (the JitLoaderGDB->MachO thing).
• they don't introduce any new dependency loops as ObjectFile plugins don't depend on any other plugins

[xiaobai]

LGTM

include/lldb/Symbol/ObjectFile.h

public:
   ///     \b true if the path matches the pattern of archive + object
   ///     and \a archive_file and \a archive_object are modified,
   ///     \b false otherwise and \a archive_file and \a archive_object
   ///     are guaranteed to be remain unchanged.
   static bool SplitArchivePathWithObject(
       const char *path_with_object, lldb_private::FileSpec &archive_file,
       lldb_private::ConstString &archive_object, bool must_exist);
 
+
+  // LLVM RTTI support
+  static char ID;
+  virtual bool isA(const void *ClassID) const { return ClassID == &ID; }
+
   /// Gets the address size in bytes for the current object file.
   ///
   /// \return
   ///     The size of an address in bytes for the currently selected
   ///     architecture (and object for archives). Returns zero if no
   ///     architecture or object has been selected.
   virtual uint32_t GetAddressByteSize() const = 0;
 

source/Plugins/JITLoader/GDB/CMakeLists.txt

add_lldb_library(lldbPluginJITLoaderGDB PLUGIN
 
   LINK_LIBS
     lldbBreakpoint
     lldbCore
     lldbInterpreter
     lldbSymbol
     lldbTarget
     lldbUtility
+    lldbPluginObjectFileMachO
   LINK_COMPONENTS
     Support
   )
 
 add_dependencies(lldbPluginJITLoaderGDB
   LLDBPluginJITLoaderGDBPropertiesGen
   LLDBPluginJITLoaderGDBPropertiesEnumGen)

source/Plugins/JITLoader/GDB/JITLoaderGDB.cpp

 //===-- JITLoaderGDB.cpp ----------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-
-#include "llvm/Support/MathExtras.h"
-
+#include "JITLoaderGDB.h"
+#include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
 #include "lldb/Breakpoint/Breakpoint.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Interpreter/OptionValueProperties.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Symbol/Symbol.h"
 #include "lldb/Symbol/SymbolContext.h"
 #include "lldb/Symbol/SymbolVendor.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/SectionLoadList.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/LLDBAssert.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/StreamString.h"
-
-#include "JITLoaderGDB.h"
+#include "llvm/Support/MathExtras.h"
 
 #include <memory>
 
 using namespace lldb;
 using namespace lldb_private;
 
 // Debug Interface Structures
 enum jit_actions_t { JIT_NOACTION = 0, JIT_REGISTER_FN, JIT_UNREGISTER_FN };
if (jit_action == JIT_REGISTER_FN) {
         // Object formats (like ELF) have no representation for a JIT type.
         // We will get it wrong, if we deduce it from the header.
         module_sp->GetObjectFile()->SetType(ObjectFile::eTypeJIT);
 
         // load the symbol table right away
         module_sp->GetObjectFile()->GetSymtab();
 
         m_jit_objects.insert(std::make_pair(symbolfile_addr, module_sp));
-        if (module_sp->GetObjectFile()->GetPluginName() ==
-            ConstString("mach-o")) {
-          ObjectFile *image_object_file = module_sp->GetObjectFile();
-          if (image_object_file) {
-            const SectionList *section_list =
-                image_object_file->GetSectionList();
-            if (section_list) {
-              uint64_t vmaddrheuristic = 0;
-              uint64_t lower = (uint64_t)-1;
-              uint64_t upper = 0;
-              updateSectionLoadAddress(*section_list, target, symbolfile_addr,
-                                       symbolfile_size, vmaddrheuristic, lower,
-                                       upper);
-            }
-          }
+        if (auto image_object_file =
+                llvm::dyn_cast<ObjectFileMachO>(module_sp->GetObjectFile())) {
+          const SectionList *section_list = image_object_file->GetSectionList();
         } else {
           bool changed = false;
           module_sp->SetLoadAddress(target, 0, true, changed);
         }
 
         module_list.AppendIfNeeded(module_sp);
 
         ModuleList module_list;

source/Plugins/ObjectFile/Breakpad/ObjectFileBreakpad.h

static size_t GetModuleSpecifications(const FileSpec &file,
                                         lldb::offset_t length,
                                         ModuleSpecList &specs);
 
   // PluginInterface protocol
   ConstString GetPluginName() override { return GetPluginNameStatic(); }
 
   uint32_t GetPluginVersion() override { return 1; }
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   // ObjectFile Protocol.
 
   bool ParseHeader() override;
 
   lldb::ByteOrder GetByteOrder() const override {
     return m_arch.GetByteOrder();
   }
 

source/Plugins/ObjectFile/Breakpad/ObjectFileBreakpad.cpp

llvm::Optional<Header> Header::parse(llvm::StringRef text) {
 
   std::tie(line, text) = text.split('\n');
 
   auto Info = InfoRecord::parse(line);
   UUID uuid = Info && Info->ID ? Info->ID : Module->ID;
   return Header{ArchSpec(triple), std::move(uuid)};
 }
 
+char ObjectFileBreakpad::ID;
+
 void ObjectFileBreakpad::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance,
                                 CreateMemoryInstance, GetModuleSpecifications);
 }
 
 void ObjectFileBreakpad::Terminate() {
   PluginManager::UnregisterPlugin(CreateInstance);

source/Plugins/ObjectFile/ELF/ObjectFileELF.h

public:
   static bool MagicBytesMatch(lldb::DataBufferSP &data_sp, lldb::addr_t offset,
                               lldb::addr_t length);
 
   // PluginInterface protocol
   lldb_private::ConstString GetPluginName() override;
 
   uint32_t GetPluginVersion() override;
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   // ObjectFile Protocol.
   bool ParseHeader() override;
 
   bool SetLoadAddress(lldb_private::Target &target, lldb::addr_t value,
                       bool value_is_offset) override;
 
   lldb::ByteOrder GetByteOrder() const override;
 

source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

 
 static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
   if (header.e_machine == llvm::ELF::EM_MIPS)
     return mipsVariantFromElfFlags(header);
 
   return LLDB_INVALID_CPUTYPE;
 }
 
+char ObjectFileELF::ID;
+
 // Arbitrary constant used as UUID prefix for core files.
 const uint32_t ObjectFileELF::g_core_uuid_magic(0xE210C);
 
 // Static methods.
 void ObjectFileELF::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance,
                                 CreateMemoryInstance, GetModuleSpecifications);

source/Plugins/ObjectFile/JIT/ObjectFileJIT.h

public:
 
   static size_t GetModuleSpecifications(const lldb_private::FileSpec &file,
                                         lldb::DataBufferSP &data_sp,
                                         lldb::offset_t data_offset,
                                         lldb::offset_t file_offset,
                                         lldb::offset_t length,
                                         lldb_private::ModuleSpecList &specs);
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   // Member Functions
   bool ParseHeader() override;
 
   bool SetLoadAddress(lldb_private::Target &target, lldb::addr_t value,
                       bool value_is_offset) override;
 
   lldb::ByteOrder GetByteOrder() const override;
 

source/Plugins/ObjectFile/JIT/ObjectFileJIT.cpp

 
 #ifndef __APPLE__
 #include "Utility/UuidCompatibility.h"
 #endif
 
 using namespace lldb;
 using namespace lldb_private;
 
+char ObjectFileJIT::ID;
+
 void ObjectFileJIT::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance,
                                 CreateMemoryInstance, GetModuleSpecifications);
 }
 
 void ObjectFileJIT::Terminate() {
   PluginManager::UnregisterPlugin(CreateInstance);

source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h

public:
 
   static bool SaveCore(const lldb::ProcessSP &process_sp,
                        const lldb_private::FileSpec &outfile,
                        lldb_private::Status &error);
 
   static bool MagicBytesMatch(lldb::DataBufferSP &data_sp, lldb::addr_t offset,
                               lldb::addr_t length);
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   // Member Functions
   bool ParseHeader() override;
 
   bool SetLoadAddress(lldb_private::Target &target, lldb::addr_t value,
                       bool value_is_offset) override;
 
   lldb::ByteOrder GetByteOrder() const override;
 

source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

static uint32_t MachHeaderSizeFromMagic(uint32_t magic) {
   default:
     break;
   }
   return 0;
 }
 
 #define MACHO_NLIST_ARM_SYMBOL_IS_THUMB 0x0008
 
+char ObjectFileMachO::ID;
+
 void ObjectFileMachO::Initialize() {
   PluginManager::RegisterPlugin(
       GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance,
       CreateMemoryInstance, GetModuleSpecifications, SaveCore);
 }
 
 void ObjectFileMachO::Terminate() {
   PluginManager::UnregisterPlugin(CreateInstance);

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h

public:
   static bool SaveCore(const lldb::ProcessSP &process_sp,
                        const lldb_private::FileSpec &outfile,
                        lldb_private::Status &error);
 
   static bool MagicBytesMatch(lldb::DataBufferSP &data_sp);
 
   static lldb::SymbolType MapSymbolType(uint16_t coff_symbol_type);
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   bool ParseHeader() override;
 
   bool SetLoadAddress(lldb_private::Target &target, lldb::addr_t value,
                       bool value_is_offset) override;
 
   lldb::ByteOrder GetByteOrder() const override;
 
   bool IsExecutable() const override;

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

if (pdb_info->PDB70.CVSignature == llvm::OMF::Signature::PDB70) {
       // Otherwise return 16-byte GUID
       return UUID::fromOptionalData(&info.Guid, sizeof(info.Guid));
     }
   }
 
   return UUID();
 }
 
+char ObjectFilePECOFF::ID;
+
 void ObjectFilePECOFF::Initialize() {
   PluginManager::RegisterPlugin(
       GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance,
       CreateMemoryInstance, GetModuleSpecifications, SaveCore);
 }
 
 void ObjectFilePECOFF::Terminate() {
   PluginManager::UnregisterPlugin(CreateInstance);

source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp

 }
 
 ConstString SymbolFileBreakpad::GetPluginNameStatic() {
   static ConstString g_name("breakpad");
   return g_name;
 }
 
 uint32_t SymbolFileBreakpad::CalculateAbilities() {
-  if (!m_obj_file)
-    return 0;
-  if (m_obj_file->GetPluginName() != ObjectFileBreakpad::GetPluginNameStatic())
+  if (!m_obj_file || !llvm::isa<ObjectFileBreakpad>(m_obj_file))
     return 0;
 
   return CompileUnits | Functions | LineTables;
 }
 
 uint32_t SymbolFileBreakpad::CalculateNumCompileUnits() {
   ParseCUData();
   return m_cu_data->GetSize();

source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

loadMatchingPDBFile(std::string exe_path, llvm::BumpPtrAllocator &allocator) {
 
   // If the file isn't a PE/COFF executable, fail.
   if (!expected_binary) {
     llvm::consumeError(expected_binary.takeError());
     return nullptr;
   }
   OwningBinary<Binary> binary = std::move(*expected_binary);
 
+  // TODO: Avoid opening the PE/COFF binary twice by reading this information
+  // directly from the lldb_private::ObjectFile.
   auto *obj = llvm::dyn_cast<llvm::object::COFFObjectFile>(binary.getBinary());
   if (!obj)
     return nullptr;
   const llvm::codeview::DebugInfo *pdb_info = nullptr;
 
   // If it doesn't have a debug directory, fail.
   llvm::StringRef pdb_file;
   auto ec = obj->getDebugPDBInfo(pdb_info, pdb_file);

source/Plugins/SymbolVendor/ELF/CMakeLists.txt

 add_lldb_library(lldbPluginSymbolVendorELF PLUGIN
   SymbolVendorELF.cpp
 
   LINK_LIBS
     lldbCore
     lldbHost
     lldbSymbol
+    lldbPluginObjectFileELF
   )

source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp

 //===-- SymbolVendorELF.cpp ----------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "SymbolVendorELF.h"
 
 #include <string.h>
 
+#include "Plugins/ObjectFile/ELF/ObjectFileELF.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Symbol/LocateSymbolFile.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Target/Target.h"

 // allow for complex debug information file setups, and to also allow for
 // finding separate debug information files.
 SymbolVendor *
 SymbolVendorELF::CreateInstance(const lldb::ModuleSP &module_sp,
                                 lldb_private::Stream *feedback_strm) {
   if (!module_sp)
     return nullptr;
 
-  ObjectFile *obj_file = module_sp->GetObjectFile();
+  ObjectFileELF *obj_file =
+      llvm::dyn_cast_or_null<ObjectFileELF>(module_sp->GetObjectFile());
   if (!obj_file)
     return nullptr;
 
-  static ConstString obj_file_elf("elf");
-  ConstString obj_name = obj_file->GetPluginName();
-  if (obj_name != obj_file_elf)
-    return nullptr;
-
   lldb_private::UUID uuid = obj_file->GetUUID();
   if (!uuid)
     return nullptr;
 
   // Get the .gnu_debuglink file (if specified).
   FileSpecList file_spec_list = obj_file->GetDebugSymbolFilePaths();
 
   // If the module specified a filespec, use it first.

source/Plugins/SymbolVendor/MacOSX/CMakeLists.txt

 include_directories(${LIBXML2_INCLUDE_DIR})
 
 add_lldb_library(lldbPluginSymbolVendorMacOSX PLUGIN
   SymbolVendorMacOSX.cpp
 
   LINK_LIBS
     lldbCore
     lldbHost
     lldbSymbol
+    lldbPluginObjectFileMachO
   )

source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp

 //===-- SymbolVendorMacOSX.cpp ----------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "SymbolVendorMacOSX.h"
 
 #include <string.h>
 
+#include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/XML.h"
 #include "lldb/Symbol/LocateSymbolFile.h"
 #include "lldb/Symbol/ObjectFile.h"

 // allow for complex debug information file setups, and to also allow for
 // finding separate debug information files.
 SymbolVendor *
 SymbolVendorMacOSX::CreateInstance(const lldb::ModuleSP &module_sp,
                                    lldb_private::Stream *feedback_strm) {
   if (!module_sp)
     return NULL;
 
-  ObjectFile *obj_file = module_sp->GetObjectFile();
+  ObjectFile *obj_file =
+      llvm::dyn_cast_or_null<ObjectFileMachO>(module_sp->GetObjectFile());
   if (!obj_file)
     return NULL;
 
-  static ConstString obj_file_macho("mach-o");
-  ConstString obj_name = obj_file->GetPluginName();
-  if (obj_name != obj_file_macho)
-    return NULL;
-
   static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
   Timer scoped_timer(func_cat,
                      "SymbolVendorMacOSX::CreateInstance (module = %s)",
                      module_sp->GetFileSpec().GetPath().c_str());
   SymbolVendorMacOSX *symbol_vendor = new SymbolVendorMacOSX(module_sp);
   if (symbol_vendor) {
     char path[PATH_MAX];
     path[0] = '\0';

source/Symbol/ObjectFile.cpp

 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/RegularExpression.h"
 #include "lldb/Utility/Timer.h"
 #include "lldb/lldb-private.h"
 
 using namespace lldb;
 using namespace lldb_private;
 
+char ObjectFile::ID;
+
 ObjectFileSP
 ObjectFile::FindPlugin(const lldb::ModuleSP &module_sp, const FileSpec *file,
                        lldb::offset_t file_offset, lldb::offset_t file_size,
                        DataBufferSP &data_sp, lldb::offset_t &data_offset) {
   ObjectFileSP object_file_sp;
 
   if (module_sp) {
     static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);