Minidump plugin: Adding ProcessMinidump, ThreadMinidump and register the plugin in SystemInitializerFull

Summary:
This plugin resembles the already existing Windows-only Minidump plugin.
The WinMinidumpPlugin uses the Windows API for parsing Minidumps
while this plugin is cross-platform because it includes a Minidump
parser (which is already commited)

It is able to produce a backtrace, to read the general puprose regiters,
inspect local variables, show image list, do memory reads, etc.

For now the only arches that this supports are x86_32 and x86_64.
This is because I have only written register contexts for those.
Others will come in next CLs.

I copied the WinMinidump tests and adapted them a little bit for them to
work with the new plugin (and they pass)
I will add more tests, aiming for better code coverage.

There is still functionality to be added, see TODOs in code.

Reviewers: labath, zturner

Subscribers: beanz, mgorny, modocache, lldb-commits, amccarth

Differential Revision: https://reviews.llvm.org/D25905

llvm-svn: 285587
diff --git a/lldb/source/Plugins/Process/minidump/CMakeLists.txt b/lldb/source/Plugins/Process/minidump/CMakeLists.txt
index 92d831a..ddc89cb 100644
--- a/lldb/source/Plugins/Process/minidump/CMakeLists.txt
+++ b/lldb/source/Plugins/Process/minidump/CMakeLists.txt
@@ -5,4 +5,6 @@
   MinidumpParser.cpp
   RegisterContextMinidump_x86_32.cpp
   RegisterContextMinidump_x86_64.cpp
+  ProcessMinidump.cpp
+  ThreadMinidump.cpp
   )
diff --git a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
index abb0810..37b3709 100644
--- a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
+++ b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
@@ -9,6 +9,8 @@
 
 // Project includes
 #include "MinidumpParser.h"
+#include "NtStructures.h"
+#include "RegisterContextMinidump_x86_32.h"
 
 // Other libraries and framework includes
 #include "lldb/Target/MemoryRegionInfo.h"
@@ -106,11 +108,42 @@
 llvm::ArrayRef<uint8_t>
 MinidumpParser::GetThreadContext(const MinidumpThread &td) {
   if (td.thread_context.rva + td.thread_context.data_size > GetData().size())
-    return llvm::None;
+    return {};
 
   return GetData().slice(td.thread_context.rva, td.thread_context.data_size);
 }
 
+llvm::ArrayRef<uint8_t>
+MinidumpParser::GetThreadContextWow64(const MinidumpThread &td) {
+  // On Windows, a 32-bit process can run on a 64-bit machine under
+  // WOW64. If the minidump was captured with a 64-bit debugger, then
+  // the CONTEXT we just grabbed from the mini_dump_thread is the one
+  // for the 64-bit "native" process rather than the 32-bit "guest"
+  // process we care about.  In this case, we can get the 32-bit CONTEXT
+  // from the TEB (Thread Environment Block) of the 64-bit process.
+  auto teb_mem = GetMemory(td.teb, sizeof(TEB64));
+  if (teb_mem.empty())
+    return {};
+
+  const TEB64 *wow64teb;
+  Error error = consumeObject(teb_mem, wow64teb);
+  if (error.Fail())
+    return {};
+
+  // Slot 1 of the thread-local storage in the 64-bit TEB points to a
+  // structure that includes the 32-bit CONTEXT (after a ULONG).
+  // See:  https://msdn.microsoft.com/en-us/library/ms681670.aspx
+  auto context =
+      GetMemory(wow64teb->tls_slots[1] + 4, sizeof(MinidumpContext_x86_32));
+  if (context.size() < sizeof(MinidumpContext_x86_32))
+    return {};
+
+  return context;
+  // NOTE:  We don't currently use the TEB for anything else.  If we
+  // need it in the future, the 32-bit TEB is located according to the address
+  // stored in the first slot of the 64-bit TEB (wow64teb.Reserved1[0]).
+}
+
 const MinidumpSystemInfo *MinidumpParser::GetSystemInfo() {
   llvm::ArrayRef<uint8_t> data = GetStream(MinidumpStreamType::SystemInfo);
 
@@ -229,8 +262,7 @@
 
 std::vector<const MinidumpModule *> MinidumpParser::GetFilteredModuleList() {
   llvm::ArrayRef<MinidumpModule> modules = GetModuleList();
-  // mapping module_name to pair(load_address, pointer to module struct in
-  // memory)
+  // map module_name -> pair(load_address, pointer to module struct in memory)
   llvm::StringMap<std::pair<uint64_t, const MinidumpModule *>> lowest_addr;
 
   std::vector<const MinidumpModule *> filtered_modules;
diff --git a/lldb/source/Plugins/Process/minidump/MinidumpParser.h b/lldb/source/Plugins/Process/minidump/MinidumpParser.h
index 202ef37..67523a7 100644
--- a/lldb/source/Plugins/Process/minidump/MinidumpParser.h
+++ b/lldb/source/Plugins/Process/minidump/MinidumpParser.h
@@ -59,6 +59,8 @@
 
   llvm::ArrayRef<uint8_t> GetThreadContext(const MinidumpThread &td);
 
+  llvm::ArrayRef<uint8_t> GetThreadContextWow64(const MinidumpThread &td);
+
   const MinidumpSystemInfo *GetSystemInfo();
 
   ArchSpec GetArchitecture();
diff --git a/lldb/source/Plugins/Process/minidump/MinidumpTypes.h b/lldb/source/Plugins/Process/minidump/MinidumpTypes.h
index 1b90307..8c996d0 100644
--- a/lldb/source/Plugins/Process/minidump/MinidumpTypes.h
+++ b/lldb/source/Plugins/Process/minidump/MinidumpTypes.h
@@ -439,7 +439,8 @@
 // Exception stuff
 struct MinidumpException {
   enum {
-    MaxParams = 15,
+    ExceptonInfoMaxParams = 15,
+    DumpRequested = 0xFFFFFFFF,
   };
 
   llvm::support::ulittle32_t exception_code;
@@ -448,7 +449,7 @@
   llvm::support::ulittle64_t exception_address;
   llvm::support::ulittle32_t number_parameters;
   llvm::support::ulittle32_t unused_alignment;
-  llvm::support::ulittle64_t exception_information[MaxParams];
+  llvm::support::ulittle64_t exception_information[ExceptonInfoMaxParams];
 };
 static_assert(sizeof(MinidumpException) == 152,
               "sizeof MinidumpException is not correct!");
diff --git a/lldb/source/Plugins/Process/minidump/NtStructures.h b/lldb/source/Plugins/Process/minidump/NtStructures.h
new file mode 100644
index 0000000..c0afd77
--- /dev/null
+++ b/lldb/source/Plugins/Process/minidump/NtStructures.h
@@ -0,0 +1,37 @@
+//===-- NtStructures.h ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_Plugins_Process_Minidump_NtStructures_h_
+#define liblldb_Plugins_Process_Minidump_NtStructures_h_
+
+#include "llvm/Support/Endian.h"
+
+namespace lldb_private {
+
+namespace minidump {
+
+// This describes the layout of a TEB (Thread Environment Block) for a 64-bit
+// process.  It's adapted from the 32-bit TEB in winternl.h.  Currently, we care
+// only about the position of the tls_slots.
+struct TEB64 {
+  llvm::support::ulittle64_t reserved1[12];
+  llvm::support::ulittle64_t process_environment_block;
+  llvm::support::ulittle64_t reserved2[399];
+  uint8_t reserved3[1952];
+  llvm::support::ulittle64_t tls_slots[64];
+  uint8_t reserved4[8];
+  llvm::support::ulittle64_t reserved5[26];
+  llvm::support::ulittle64_t reserved_for_ole; // Windows 2000 only
+  llvm::support::ulittle64_t reserved6[4];
+  llvm::support::ulittle64_t tls_expansion_slots;
+};
+
+#endif // liblldb_Plugins_Process_Minidump_NtStructures_h_
+} // namespace minidump
+} // namespace lldb_private
diff --git a/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp b/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp
new file mode 100644
index 0000000..fe437ce
--- /dev/null
+++ b/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp
@@ -0,0 +1,293 @@
+//===-- ProcessMinidump.cpp -------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// Project includes
+#include "ProcessMinidump.h"
+#include "ThreadMinidump.h"
+
+// Other libraries and framework includes
+#include "lldb/Core/DataBufferHeap.h"
+#include "lldb/Core/Log.h"
+#include "lldb/Core/Module.h"
+#include "lldb/Core/ModuleSpec.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Core/State.h"
+#include "lldb/Target/DynamicLoader.h"
+#include "lldb/Target/MemoryRegionInfo.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Target/UnixSignals.h"
+#include "lldb/Utility/LLDBAssert.h"
+
+// C includes
+// C++ includes
+
+using namespace lldb_private;
+using namespace minidump;
+
+ConstString ProcessMinidump::GetPluginNameStatic() {
+  static ConstString g_name("minidump");
+  return g_name;
+}
+
+const char *ProcessMinidump::GetPluginDescriptionStatic() {
+  return "Minidump plug-in.";
+}
+
+lldb::ProcessSP ProcessMinidump::CreateInstance(lldb::TargetSP target_sp,
+                                                lldb::ListenerSP listener_sp,
+                                                const FileSpec *crash_file) {
+  if (!crash_file)
+    return nullptr;
+
+  lldb::ProcessSP process_sp;
+  // Read enough data for the Minidump header
+  const size_t header_size = sizeof(MinidumpHeader);
+  lldb::DataBufferSP data_sp(crash_file->MemoryMapFileContents(0, header_size));
+  if (!data_sp)
+    return nullptr;
+
+  // first, only try to parse the header, beacuse we need to be fast
+  llvm::ArrayRef<uint8_t> header_data(data_sp->GetBytes(), header_size);
+  const MinidumpHeader *header = MinidumpHeader::Parse(header_data);
+
+  if (data_sp->GetByteSize() != header_size || header == nullptr)
+    return nullptr;
+
+  lldb::DataBufferSP all_data_sp(crash_file->MemoryMapFileContents());
+  auto minidump_parser = MinidumpParser::Create(all_data_sp);
+  // check if the parser object is valid
+  // skip if the Minidump file is Windows generated, because we are still
+  // work-in-progress
+  if (!minidump_parser ||
+      minidump_parser->GetArchitecture().GetTriple().getOS() ==
+          llvm::Triple::OSType::Win32)
+    return nullptr;
+
+  return std::make_shared<ProcessMinidump>(target_sp, listener_sp, *crash_file,
+                                           minidump_parser.getValue());
+}
+
+bool ProcessMinidump::CanDebug(lldb::TargetSP target_sp,
+                               bool plugin_specified_by_name) {
+  return true;
+}
+
+ProcessMinidump::ProcessMinidump(lldb::TargetSP target_sp,
+                                 lldb::ListenerSP listener_sp,
+                                 const FileSpec &core_file,
+                                 MinidumpParser minidump_parser)
+    : Process(target_sp, listener_sp), m_minidump_parser(minidump_parser),
+      m_core_file(core_file), m_is_wow64(false) {}
+
+ProcessMinidump::~ProcessMinidump() {
+  Clear();
+  // We need to call finalize on the process before destroying ourselves
+  // to make sure all of the broadcaster cleanup goes as planned. If we
+  // destruct this class, then Process::~Process() might have problems
+  // trying to fully destroy the broadcaster.
+  Finalize();
+}
+
+void ProcessMinidump::Initialize() {
+  static std::once_flag g_once_flag;
+
+  std::call_once(g_once_flag, []() {
+    PluginManager::RegisterPlugin(GetPluginNameStatic(),
+                                  GetPluginDescriptionStatic(),
+                                  ProcessMinidump::CreateInstance);
+  });
+}
+
+void ProcessMinidump::Terminate() {
+  PluginManager::UnregisterPlugin(ProcessMinidump::CreateInstance);
+}
+
+Error ProcessMinidump::DoLoadCore() {
+  Error error;
+
+  m_thread_list = m_minidump_parser.GetThreads();
+  m_active_exception = m_minidump_parser.GetExceptionStream();
+  ReadModuleList();
+  GetTarget().SetArchitecture(GetArchitecture());
+
+  llvm::Optional<lldb::pid_t> pid = m_minidump_parser.GetPid();
+  if (!pid) {
+    error.SetErrorString("failed to parse PID");
+    return error;
+  }
+  SetID(pid.getValue());
+
+  return error;
+}
+
+DynamicLoader *ProcessMinidump::GetDynamicLoader() {
+  if (m_dyld_ap.get() == nullptr)
+    m_dyld_ap.reset(DynamicLoader::FindPlugin(this, nullptr));
+  return m_dyld_ap.get();
+}
+
+ConstString ProcessMinidump::GetPluginName() { return GetPluginNameStatic(); }
+
+uint32_t ProcessMinidump::GetPluginVersion() { return 1; }
+
+Error ProcessMinidump::DoDestroy() { return Error(); }
+
+void ProcessMinidump::RefreshStateAfterStop() {
+  if (!m_active_exception)
+    return;
+
+  if (m_active_exception->exception_record.exception_code ==
+      MinidumpException::DumpRequested) {
+    return;
+  }
+
+  lldb::StopInfoSP stop_info;
+  lldb::ThreadSP stop_thread;
+
+  Process::m_thread_list.SetSelectedThreadByID(m_active_exception->thread_id);
+  stop_thread = Process::m_thread_list.GetSelectedThread();
+  ArchSpec arch = GetArchitecture();
+
+  if (arch.GetTriple().getOS() == llvm::Triple::Linux) {
+    stop_info = StopInfo::CreateStopReasonWithSignal(
+        *stop_thread, m_active_exception->exception_record.exception_code);
+  } else {
+    std::string desc;
+    llvm::raw_string_ostream desc_stream(desc);
+    desc_stream << "Exception "
+                << llvm::format_hex(
+                       m_active_exception->exception_record.exception_code, 8)
+                << " encountered at address "
+                << llvm::format_hex(
+                       m_active_exception->exception_record.exception_address,
+                       8);
+    stop_info = StopInfo::CreateStopReasonWithException(
+        *stop_thread, desc_stream.str().c_str());
+  }
+
+  stop_thread->SetStopInfo(stop_info);
+}
+
+bool ProcessMinidump::IsAlive() { return true; }
+
+bool ProcessMinidump::WarnBeforeDetach() const { return false; }
+
+size_t ProcessMinidump::ReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                                   lldb_private::Error &error) {
+  // Don't allow the caching that lldb_private::Process::ReadMemory does
+  // since we have it all cached in our dump file anyway.
+  return DoReadMemory(addr, buf, size, error);
+}
+
+size_t ProcessMinidump::DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                                     lldb_private::Error &error) {
+
+  llvm::ArrayRef<uint8_t> mem = m_minidump_parser.GetMemory(addr, size);
+  if (mem.empty()) {
+    error.SetErrorString("could not parse memory info");
+    return 0;
+  }
+
+  std::memcpy(buf, mem.data(), mem.size());
+  return mem.size();
+}
+
+ArchSpec ProcessMinidump::GetArchitecture() {
+  if (!m_is_wow64) {
+    return m_minidump_parser.GetArchitecture();
+  }
+
+  llvm::Triple triple;
+  triple.setVendor(llvm::Triple::VendorType::UnknownVendor);
+  triple.setArch(llvm::Triple::ArchType::x86);
+  triple.setOS(llvm::Triple::OSType::Win32);
+  return ArchSpec(triple);
+}
+
+Error ProcessMinidump::GetMemoryRegionInfo(
+    lldb::addr_t load_addr, lldb_private::MemoryRegionInfo &range_info) {
+  Error error;
+  auto info = m_minidump_parser.GetMemoryRegionInfo(load_addr);
+  if (!info) {
+    error.SetErrorString("No valid MemoryRegionInfo found!");
+    return error;
+  }
+  range_info = info.getValue();
+  return error;
+}
+
+void ProcessMinidump::Clear() { Process::m_thread_list.Clear(); }
+
+bool ProcessMinidump::UpdateThreadList(
+    lldb_private::ThreadList &old_thread_list,
+    lldb_private::ThreadList &new_thread_list) {
+  uint32_t num_threads = 0;
+  if (m_thread_list.size() > 0)
+    num_threads = m_thread_list.size();
+
+  for (lldb::tid_t tid = 0; tid < num_threads; ++tid) {
+    llvm::ArrayRef<uint8_t> context;
+    if (!m_is_wow64)
+      context = m_minidump_parser.GetThreadContext(m_thread_list[tid]);
+    else
+      context = m_minidump_parser.GetThreadContextWow64(m_thread_list[tid]);
+
+    lldb::ThreadSP thread_sp(
+        new ThreadMinidump(*this, m_thread_list[tid], context));
+    new_thread_list.AddThread(thread_sp);
+  }
+  return new_thread_list.GetSize(false) > 0;
+}
+
+void ProcessMinidump::ReadModuleList() {
+  std::vector<const MinidumpModule *> filtered_modules =
+      m_minidump_parser.GetFilteredModuleList();
+
+  for (auto module : filtered_modules) {
+    llvm::Optional<std::string> name =
+        m_minidump_parser.GetMinidumpString(module->module_name_rva);
+
+    if (!name)
+      continue;
+
+    Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES));
+    if (log) {
+      log->Printf(
+          "ProcessMinidump::%s found module: name: %s %#010lx-%#010lx size: %u",
+          __FUNCTION__, name.getValue().c_str(),
+          uint64_t(module->base_of_image),
+          module->base_of_image + module->size_of_image,
+          uint32_t(module->size_of_image));
+    }
+
+    // check if the process is wow64 - a 32 bit windows process running on a
+    // 64 bit windows
+    if (llvm::StringRef(name.getValue()).endswith_lower("wow64.dll")) {
+      m_is_wow64 = true;
+    }
+
+    const auto file_spec = FileSpec(name.getValue(), true);
+    ModuleSpec module_spec = file_spec;
+    Error error;
+    lldb::ModuleSP module_sp = GetTarget().GetSharedModule(module_spec, &error);
+    if (!module_sp || error.Fail()) {
+      continue;
+    }
+
+    if (log) {
+      log->Printf("ProcessMinidump::%s load module: name: %s", __FUNCTION__,
+                  name.getValue().c_str());
+    }
+
+    bool load_addr_changed = false;
+    module_sp->SetLoadAddress(GetTarget(), module->base_of_image, false,
+                              load_addr_changed);
+  }
+}
diff --git a/lldb/source/Plugins/Process/minidump/ProcessMinidump.h b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
new file mode 100644
index 0000000..30637c2
--- /dev/null
+++ b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
@@ -0,0 +1,104 @@
+//===-- ProcessMinidump.h ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_ProcessMinidump_h_
+#define liblldb_ProcessMinidump_h_
+
+// Project includes
+#include "MinidumpParser.h"
+#include "MinidumpTypes.h"
+
+// Other libraries and framework includes
+#include "lldb/Core/ConstString.h"
+#include "lldb/Core/Error.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/StopInfo.h"
+#include "lldb/Target/Target.h"
+
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+
+// C Includes
+// C++ Includes
+
+namespace lldb_private {
+
+namespace minidump {
+
+class ProcessMinidump : public Process {
+public:
+  static lldb::ProcessSP CreateInstance(lldb::TargetSP target_sp,
+                                        lldb::ListenerSP listener_sp,
+                                        const FileSpec *crash_file_path);
+
+  static void Initialize();
+
+  static void Terminate();
+
+  static ConstString GetPluginNameStatic();
+
+  static const char *GetPluginDescriptionStatic();
+
+  ProcessMinidump(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp,
+                  const lldb_private::FileSpec &core_file,
+                  MinidumpParser minidump_parser);
+
+  ~ProcessMinidump() override;
+
+  bool CanDebug(lldb::TargetSP target_sp,
+                bool plugin_specified_by_name) override;
+
+  Error DoLoadCore() override;
+
+  DynamicLoader *GetDynamicLoader() override;
+
+  ConstString GetPluginName() override;
+
+  uint32_t GetPluginVersion() override;
+
+  Error DoDestroy() override;
+
+  void RefreshStateAfterStop() override;
+
+  bool IsAlive() override;
+
+  bool WarnBeforeDetach() const override;
+
+  size_t ReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                    Error &error) override;
+
+  size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                      Error &error) override;
+
+  ArchSpec GetArchitecture();
+
+  Error GetMemoryRegionInfo(lldb::addr_t load_addr,
+                            MemoryRegionInfo &range_info) override;
+
+  MinidumpParser m_minidump_parser;
+
+protected:
+  void Clear();
+
+  bool UpdateThreadList(ThreadList &old_thread_list,
+                        ThreadList &new_thread_list) override;
+
+  void ReadModuleList();
+
+private:
+  FileSpec m_core_file;
+  llvm::ArrayRef<MinidumpThread> m_thread_list;
+  const MinidumpExceptionStream *m_active_exception;
+  bool m_is_wow64;
+};
+
+} // namespace minidump
+} // namespace lldb_private
+
+#endif // liblldb_ProcessMinidump_h_
diff --git a/lldb/source/Plugins/Process/minidump/ThreadMinidump.cpp b/lldb/source/Plugins/Process/minidump/ThreadMinidump.cpp
new file mode 100644
index 0000000..e42108b
--- /dev/null
+++ b/lldb/source/Plugins/Process/minidump/ThreadMinidump.cpp
@@ -0,0 +1,114 @@
+//===-- ThreadMinidump.cpp --------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// Project includes
+#include "ThreadMinidump.h"
+#include "ProcessMinidump.h"
+
+#include "RegisterContextMinidump_x86_32.h"
+#include "RegisterContextMinidump_x86_64.h"
+
+// Other libraries and framework includes
+#include "Plugins/Process/Utility/RegisterContextLinux_i386.h"
+#include "Plugins/Process/Utility/RegisterContextLinux_x86_64.h"
+
+#include "Plugins/Process/elf-core/RegisterContextPOSIXCore_x86_64.h"
+
+#include "lldb/Core/DataExtractor.h"
+#include "lldb/Core/Log.h"
+#include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/StopInfo.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Target/Unwind.h"
+
+// C Includes
+// C++ Includes
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace minidump;
+
+ThreadMinidump::ThreadMinidump(Process &process, const MinidumpThread &td,
+                               llvm::ArrayRef<uint8_t> gpregset_data)
+    : Thread(process, td.thread_id), m_thread_reg_ctx_sp(),
+      m_gpregset_data(gpregset_data) {}
+
+ThreadMinidump::~ThreadMinidump() {}
+
+void ThreadMinidump::RefreshStateAfterStop() {}
+
+void ThreadMinidump::ClearStackFrames() {}
+
+RegisterContextSP ThreadMinidump::GetRegisterContext() {
+  if (!m_reg_context_sp) {
+    m_reg_context_sp = CreateRegisterContextForFrame(nullptr);
+  }
+  return m_reg_context_sp;
+}
+
+RegisterContextSP
+ThreadMinidump::CreateRegisterContextForFrame(StackFrame *frame) {
+  RegisterContextSP reg_ctx_sp;
+  uint32_t concrete_frame_idx = 0;
+  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
+
+  if (frame)
+    concrete_frame_idx = frame->GetConcreteFrameIndex();
+
+  if (concrete_frame_idx == 0) {
+    if (m_thread_reg_ctx_sp)
+      return m_thread_reg_ctx_sp;
+
+    ProcessMinidump *process =
+        static_cast<ProcessMinidump *>(GetProcess().get());
+    ArchSpec arch = process->GetArchitecture();
+    RegisterInfoInterface *reg_interface = nullptr;
+
+    // TODO write other register contexts and add them here
+    switch (arch.GetMachine()) {
+    case llvm::Triple::x86: {
+      reg_interface = new RegisterContextLinux_i386(arch);
+      lldb::DataBufferSP buf =
+          ConvertMinidumpContext_x86_32(m_gpregset_data, reg_interface);
+      DataExtractor gpregs(buf, lldb::eByteOrderLittle, 4);
+      DataExtractor fpregs;
+      m_thread_reg_ctx_sp.reset(new RegisterContextCorePOSIX_x86_64(
+          *this, reg_interface, gpregs, fpregs));
+      break;
+    }
+    case llvm::Triple::x86_64: {
+      reg_interface = new RegisterContextLinux_x86_64(arch);
+      lldb::DataBufferSP buf =
+          ConvertMinidumpContext_x86_64(m_gpregset_data, reg_interface);
+      DataExtractor gpregs(buf, lldb::eByteOrderLittle, 8);
+      DataExtractor fpregs;
+      m_thread_reg_ctx_sp.reset(new RegisterContextCorePOSIX_x86_64(
+          *this, reg_interface, gpregs, fpregs));
+      break;
+    }
+    default:
+      break;
+    }
+
+    if (!reg_interface) {
+      if (log)
+        log->Printf("elf-core::%s:: Architecture(%d) not supported",
+                    __FUNCTION__, arch.GetMachine());
+      assert(false && "Architecture not supported");
+    }
+
+    reg_ctx_sp = m_thread_reg_ctx_sp;
+  } else if (m_unwinder_ap) {
+    reg_ctx_sp = m_unwinder_ap->CreateRegisterContextForFrame(frame);
+  }
+
+  return reg_ctx_sp;
+}
+
+bool ThreadMinidump::CalculateStopInfo() { return false; }
diff --git a/lldb/source/Plugins/Process/minidump/ThreadMinidump.h b/lldb/source/Plugins/Process/minidump/ThreadMinidump.h
new file mode 100644
index 0000000..97db452
--- /dev/null
+++ b/lldb/source/Plugins/Process/minidump/ThreadMinidump.h
@@ -0,0 +1,52 @@
+//===-- ThreadMinidump.h ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_ThreadMinidump_h_
+#define liblldb_ThreadMinidump_h_
+
+// Project includes
+#include "MinidumpTypes.h"
+
+// Other libraries and framework includes
+#include "lldb/Target/Thread.h"
+
+// C Includes
+// C++ Includes
+
+namespace lldb_private {
+
+namespace minidump {
+
+class ThreadMinidump : public Thread {
+public:
+  ThreadMinidump(Process &process, const MinidumpThread &td,
+                 llvm::ArrayRef<uint8_t> gpregset_data);
+
+  ~ThreadMinidump() override;
+
+  void RefreshStateAfterStop() override;
+
+  lldb::RegisterContextSP GetRegisterContext() override;
+
+  lldb::RegisterContextSP
+  CreateRegisterContextForFrame(StackFrame *frame) override;
+
+  void ClearStackFrames() override;
+
+protected:
+  lldb::RegisterContextSP m_thread_reg_ctx_sp;
+  llvm::ArrayRef<uint8_t> m_gpregset_data;
+
+  bool CalculateStopInfo() override;
+};
+
+} // namespace minidump
+} // namespace lldb_private
+
+#endif // liblldb_ThreadMinidump_h_