vendor/lldb/lldb-trunk-r338150

49 files changed, 858 insertions, 1444 deletions

diff --git a/source/Host/CMakeLists.txt b/source/Host/CMakeLists.txt
index 2b6f0e48a3f20..5a92447edf308 100644
--- a/source/Host/CMakeLists.txt
+++ b/source/Host/CMakeLists.txt
@@ -3,6 +3,18 @@ macro(add_host_subdirectory group)
   source_group(${group} FILES ${ARGN})
 endmacro()
 
+# Removes all module flags from the current CMAKE_CXX_FLAGS. Used for
+# the Objective-C++ code in lldb which we don't want to build with modules.
+# Reasons for this are that modules with Objective-C++ would require that
+# all LLVM/Clang modules are Objective-C++ compatible (which they are likely
+# not) and we would have rebuild a second set of modules just for the few
+# Objective-C++ files in lldb (which slows down the build process).
+macro(remove_module_flags)
+  string(REGEX REPLACE "-fmodules-cache-path=[^ ]+" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  string(REGEX REPLACE "-fmodules" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  string(REGEX REPLACE "-fcxx-modules" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+endmacro()
+
 add_host_subdirectory(common
   common/File.cpp
   common/FileCache.cpp
@@ -39,11 +51,6 @@ add_host_subdirectory(common
   common/UDPSocket.cpp
   )
 
-# Keep track of whether we want to provide a define for the
-# Python's architecture-specific lib path (i.e. where a
-# Python lldb module would go).
-set (get_python_libdir 0)
-
 if (NOT LLDB_DISABLE_LIBEDIT)
   add_host_subdirectory(common
     common/Editline.cpp
@@ -54,10 +61,6 @@ add_host_subdirectory(posix
   posix/ConnectionFileDescriptorPosix.cpp
   )
 
-if(NOT LLDB_DISABLE_PYTHON)
-  list(APPEND LLDB_PLUGINS lldbPluginScriptInterpreterPython)
-endif()
-
 if (CMAKE_SYSTEM_NAME MATCHES "Windows")
   add_host_subdirectory(windows
     windows/ConnectionGenericFileWindows.cpp
@@ -74,11 +77,6 @@ if (CMAKE_SYSTEM_NAME MATCHES "Windows")
     windows/Windows.cpp
     )
 else()
-  if (NOT LLDB_DISABLE_PYTHON)
-    # We'll grab the arch-specific python libdir on POSIX systems.
-    set (get_python_libdir 1)
-  endif()
-
   add_host_subdirectory(posix
     posix/DomainSocket.cpp
     posix/FileSystem.cpp
@@ -92,10 +90,9 @@ else()
 
   if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
     include_directories(SYSTEM ${LIBXML2_INCLUDE_DIR})
-    add_host_subdirectory(macosx
-      macosx/Host.mm
-      macosx/HostInfoMacOSX.mm
-      macosx/HostThreadMacOSX.mm
+    add_subdirectory(macosx/objcxx)
+    set(LLDBObjCLibs lldbHostMacOSXObjCXX)
+    add_host_subdirectory(maqcosx
       macosx/Symbols.cpp
       macosx/cfcpp/CFCBundle.cpp
       macosx/cfcpp/CFCData.cpp
@@ -144,19 +141,6 @@ else()
   endif()
 endif()
 
-if (${get_python_libdir})
-  # Call a python script to gather the arch-specific libdir for
-  # modules like the lldb module.
-  execute_process(
-    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/../../scripts/get_relative_lib_dir.py
-    RESULT_VARIABLE get_libdir_status
-    OUTPUT_VARIABLE relative_libdir
-    )
-  if (get_libdir_status EQUAL 0)
-    add_definitions(-DLLDB_PYTHON_RELATIVE_LIBDIR="${relative_libdir}")
-  endif()
-endif()
-
 set(EXTRA_LIBS)
 if (CMAKE_SYSTEM_NAME MATCHES "NetBSD")
   list(APPEND EXTRA_LIBS kvm)
@@ -177,16 +161,16 @@ endif()
 
 add_lldb_library(lldbHost
   ${HOST_SOURCES}
-  
+
   LINK_LIBS
     lldbCore
-    lldbInterpreter
     lldbSymbol
     lldbTarget
     lldbUtility
-    ${LLDB_PLUGINS}
     ${EXTRA_LIBS}
-  
+    ${LLDBObjCLibs}
+
   LINK_COMPONENTS
+    Object
     Support
   )
diff --git a/source/Host/android/HostInfoAndroid.cpp b/source/Host/android/HostInfoAndroid.cpp
index 27ce17a76d70c..a960332832126 100644
--- a/source/Host/android/HostInfoAndroid.cpp
+++ b/source/Host/android/HostInfoAndroid.cpp
@@ -79,13 +79,10 @@ bool HostInfoAndroid::ComputeTempFileBaseDirectory(FileSpec &file_spec) {
   bool success = HostInfoLinux::ComputeTempFileBaseDirectory(file_spec);
 
   // On Android, there is no path which is guaranteed to be writable. If the
-  // user has not
-  // provided a path via an environment variable, the generic algorithm will
-  // deduce /tmp, which
-  // is plain wrong. In that case we have an invalid directory, we substitute
-  // the path with
-  // /data/local/tmp, which is correct at least in some cases (i.e., when
-  // running as shell user).
+  // user has not provided a path via an environment variable, the generic
+  // algorithm will deduce /tmp, which is plain wrong. In that case we have an
+  // invalid directory, we substitute the path with /data/local/tmp, which is
+  // correct at least in some cases (i.e., when running as shell user).
   if (!success || !file_spec.Exists())
     file_spec = FileSpec("/data/local/tmp", false);
 
diff --git a/source/Host/common/Editline.cpp b/source/Host/common/Editline.cpp
index 7b580dde656ac..329c0c1f3b707 100644
--- a/source/Host/common/Editline.cpp
+++ b/source/Host/common/Editline.cpp
@@ -33,8 +33,8 @@ using namespace lldb_private::line_editor;
 // doesn't explicitly initialize the curses termcap library, which it gets away
 // with until TERM is set to VT100 where it stumbles over an implementation
 // assumption that may not exist on other platforms.  The setupterm() function
-// would normally require headers that don't work gracefully in this context, so
-// the function declaraction has been hoisted here.
+// would normally require headers that don't work gracefully in this context,
+// so the function declaraction has been hoisted here.
 #if defined(__APPLE__)
 extern "C" {
 int setupterm(char *term, int fildes, int *errret);
@@ -43,12 +43,10 @@ int setupterm(char *term, int fildes, int *errret);
 #endif
 
 // Editline uses careful cursor management to achieve the illusion of editing a
-// multi-line block of text
-// with a single line editor.  Preserving this illusion requires fairly careful
-// management of cursor
-// state.  Read and understand the relationship between DisplayInput(),
-// MoveCursor(), SetCurrentLine(),
-// and SaveEditedLine() before making changes.
+// multi-line block of text with a single line editor.  Preserving this
+// illusion requires fairly careful management of cursor state.  Read and
+// understand the relationship between DisplayInput(), MoveCursor(),
+// SetCurrentLine(), and SaveEditedLine() before making changes.
 
 #define ESCAPE "\x1b"
 #define ANSI_FAINT ESCAPE "[2m"
@@ -70,8 +68,7 @@ int setupterm(char *term, int fildes, int *errret);
 #define EditLineStringFormatSpec "%s"
 
 // use #defines so wide version functions and structs will resolve to old
-// versions
-// for case of libedit not built with wide char support
+// versions for case of libedit not built with wide char support
 #define history_w history
 #define history_winit history_init
 #define history_wend history_end
@@ -145,10 +142,8 @@ bool IsInputPending(FILE *file) {
   // FIXME: This will be broken on Windows if we ever re-enable Editline.  You
   // can't use select
   // on something that isn't a socket.  This will have to be re-written to not
-  // use a FILE*, but
-  // instead use some kind of yet-to-be-created abstraction that select-like
-  // functionality on
-  // non-socket objects.
+  // use a FILE*, but instead use some kind of yet-to-be-created abstraction
+  // that select-like functionality on non-socket objects.
   const int fd = fileno(file);
   SelectHelper select_helper;
   select_helper.SetTimeout(std::chrono::microseconds(0));
@@ -160,13 +155,13 @@ namespace lldb_private {
 namespace line_editor {
 typedef std::weak_ptr<EditlineHistory> EditlineHistoryWP;
 
-// EditlineHistory objects are sometimes shared between multiple
-// Editline instances with the same program name.
+// EditlineHistory objects are sometimes shared between multiple Editline
+// instances with the same program name.
 
 class EditlineHistory {
 private:
-  // Use static GetHistory() function to get a EditlineHistorySP to one of these
-  // objects
+  // Use static GetHistory() function to get a EditlineHistorySP to one of
+  // these objects
   EditlineHistory(const std::string &prefix, uint32_t size, bool unique_entries)
       : m_history(NULL), m_event(), m_prefix(prefix), m_path() {
     m_history = history_winit();
@@ -436,11 +431,10 @@ unsigned char Editline::RecallHistory(bool earlier) {
     if (history_w(pHistory, &history_event, H_FIRST) == -1)
       return CC_ERROR;
 
-    // Save any edits to the "live" entry in case we return by moving forward in
-    // history
-    // (it would be more bash-like to save over any current entry, but libedit
-    // doesn't
-    // offer the ability to add entries anywhere except the end.)
+    // Save any edits to the "live" entry in case we return by moving forward
+    // in history (it would be more bash-like to save over any current entry,
+    // but libedit doesn't offer the ability to add entries anywhere except the
+    // end.)
     SaveEditedLine();
     m_live_history_lines = m_input_lines;
     m_in_history = true;
@@ -466,8 +460,7 @@ unsigned char Editline::RecallHistory(bool earlier) {
   DisplayInput();
 
   // Prepare to edit the last line when moving to previous entry, or the first
-  // line
-  // when moving to next entry
+  // line when moving to next entry
   SetCurrentLine(m_current_line_index =
                      earlier ? (int)m_input_lines.size() - 1 : 0);
   MoveCursor(CursorLocation::BlockEnd, CursorLocation::EditingPrompt);
@@ -490,8 +483,8 @@ int Editline::GetCharacter(EditLineGetCharType *c) {
   }
 
   if (m_multiline_enabled) {
-    // Detect when the number of rows used for this input line changes due to an
-    // edit
+    // Detect when the number of rows used for this input line changes due to
+    // an edit
     int lineLength = (int)((info->lastchar - info->buffer) + GetPromptWidth());
     int new_line_rows = (lineLength / m_terminal_width) + 1;
     if (m_current_line_rows != -1 && new_line_rows != m_current_line_rows) {
@@ -510,12 +503,10 @@ int Editline::GetCharacter(EditLineGetCharType *c) {
     char ch = 0;
 
     // This mutex is locked by our caller (GetLine). Unlock it while we read a
-    // character
-    // (blocking operation), so we do not hold the mutex indefinitely. This
-    // gives a chance
-    // for someone to interrupt us. After Read returns, immediately lock the
-    // mutex again and
-    // check if we were interrupted.
+    // character (blocking operation), so we do not hold the mutex
+    // indefinitely. This gives a chance for someone to interrupt us. After
+    // Read returns, immediately lock the mutex again and check if we were
+    // interrupted.
     m_output_mutex.unlock();
     int read_count = m_input_connection.Read(&ch, 1, llvm::None, status, NULL);
     m_output_mutex.lock();
@@ -614,7 +605,8 @@ unsigned char Editline::EndOrAddLineCommand(int ch) {
   // Save any edits to this line
   SaveEditedLine();
 
-  // If this is the end of the last line, consider whether to add a line instead
+  // If this is the end of the last line, consider whether to add a line
+  // instead
   const LineInfoW *info = el_wline(m_editline);
   if (m_current_line_index == m_input_lines.size() - 1 &&
       info->cursor == info->lastchar) {
@@ -653,8 +645,8 @@ unsigned char Editline::DeleteNextCharCommand(int ch) {
     return CC_REFRESH;
   }
 
-  // Fail when at the end of the last line, except when ^D is pressed on
-  // the line is empty, in which case it is treated as EOF
+  // Fail when at the end of the last line, except when ^D is pressed on the
+  // line is empty, in which case it is treated as EOF
   if (m_current_line_index == m_input_lines.size() - 1) {
     if (ch == 4 && info->buffer == info->lastchar) {
       fprintf(m_output_file, "^D\n");
@@ -685,7 +677,8 @@ unsigned char Editline::DeleteNextCharCommand(int ch) {
 unsigned char Editline::DeletePreviousCharCommand(int ch) {
   LineInfoW *info = const_cast<LineInfoW *>(el_wline(m_editline));
 
-  // Just delete the previous character normally when not at the start of a line
+  // Just delete the previous character normally when not at the start of a
+  // line
   if (info->cursor > info->buffer) {
     el_deletestr(m_editline, 1);
     return CC_REFRESH;
@@ -709,8 +702,7 @@ unsigned char Editline::DeletePreviousCharCommand(int ch) {
   DisplayInput(m_current_line_index);
 
   // Put the cursor back where libedit expects it to be before returning to
-  // editing
-  // by telling libedit about the newly inserted text
+  // editing by telling libedit about the newly inserted text
   MoveCursor(CursorLocation::BlockEnd, CursorLocation::EditingPrompt);
   el_winsertstr(m_editline, priorLine.c_str());
   return CC_REDISPLAY;
@@ -762,7 +754,8 @@ unsigned char Editline::NextLineCommand(int ch) {
         EditLineStringType(indentation, EditLineCharType(' ')));
   }
 
-  // Move down past the current line using newlines to force scrolling if needed
+  // Move down past the current line using newlines to force scrolling if
+  // needed
   SetCurrentLine(m_current_line_index + 1);
   const LineInfoW *info = el_wline(m_editline);
   int cursor_position = (int)((info->cursor - info->buffer) + GetPromptWidth());
@@ -824,8 +817,7 @@ unsigned char Editline::FixIndentationCommand(int ch) {
   DisplayInput(m_current_line_index);
 
   // Reposition the cursor back on the original line and prepare to restart
-  // editing
-  // with a new cursor position
+  // editing with a new cursor position
   SetCurrentLine(m_current_line_index);
   MoveCursor(CursorLocation::BlockEnd, CursorLocation::EditingPrompt);
   m_revert_cursor_index = cursor_position + indent_correction;
@@ -945,9 +937,9 @@ void Editline::ConfigureEditor(bool multiline) {
   m_multiline_enabled = multiline;
 
   if (m_editline) {
-    // Disable edit mode to stop the terminal from flushing all input
-    // during the call to el_end() since we expect to have multiple editline
-    // instances in this program.
+    // Disable edit mode to stop the terminal from flushing all input during
+    // the call to el_end() since we expect to have multiple editline instances
+    // in this program.
     el_set(m_editline, EL_EDITMODE, 0);
     el_end(m_editline);
   }
@@ -973,7 +965,8 @@ void Editline::ConfigureEditor(bool multiline) {
             return Editline::InstanceFor(editline)->GetCharacter(c);
           }));
 
-  // Commands used for multiline support, registered whether or not they're used
+  // Commands used for multiline support, registered whether or not they're
+  // used
   el_wset(m_editline, EL_ADDFN, EditLineConstString("lldb-break-line"),
           EditLineConstString("Insert a line break"),
           (EditlineCommandCallbackType)([](EditLine *editline, int ch) {
@@ -1031,13 +1024,11 @@ void Editline::ConfigureEditor(bool multiline) {
             return Editline::InstanceFor(editline)->FixIndentationCommand(ch);
           }));
 
-  // Register the complete callback under two names for compatibility with older
-  // clients using
-  // custom .editrc files (largely because libedit has a bad bug where if you
-  // have a bind command
-  // that tries to bind to a function name that doesn't exist, it can corrupt
-  // the heap and
-  // crash your process later.)
+  // Register the complete callback under two names for compatibility with
+  // older clients using custom .editrc files (largely because libedit has a
+  // bad bug where if you have a bind command that tries to bind to a function
+  // name that doesn't exist, it can corrupt the heap and crash your process
+  // later.)
   EditlineCommandCallbackType complete_callback = [](EditLine *editline,
                                                      int ch) {
     return Editline::InstanceFor(editline)->TabCommand(ch);
@@ -1118,8 +1109,7 @@ void Editline::ConfigureEditor(bool multiline) {
              NULL);
 
       // Escape is absorbed exiting edit mode, so re-register important
-      // sequences
-      // without the prefix
+      // sequences without the prefix
       el_set(m_editline, EL_BIND, "-a", "[A", "lldb-previous-line", NULL);
       el_set(m_editline, EL_BIND, "-a", "[B", "lldb-next-line", NULL);
       el_set(m_editline, EL_BIND, "-a", "[\\^", "lldb-revert-line", NULL);
@@ -1176,18 +1166,18 @@ Editline::Editline(const char *editline_name, FILE *input_file,
 
 Editline::~Editline() {
   if (m_editline) {
-    // Disable edit mode to stop the terminal from flushing all input
-    // during the call to el_end() since we expect to have multiple editline
-    // instances in this program.
+    // Disable edit mode to stop the terminal from flushing all input during
+    // the call to el_end() since we expect to have multiple editline instances
+    // in this program.
     el_set(m_editline, EL_EDITMODE, 0);
     el_end(m_editline);
     m_editline = nullptr;
   }
 
-  // EditlineHistory objects are sometimes shared between multiple
-  // Editline instances with the same program name. So just release
-  // our shared pointer and if we are the last owner, it will save the
-  // history to the history save file automatically.
+  // EditlineHistory objects are sometimes shared between multiple Editline
+  // instances with the same program name. So just release our shared pointer
+  // and if we are the last owner, it will save the history to the history save
+  // file automatically.
   m_history_sp.reset();
 }
 
@@ -1313,8 +1303,8 @@ bool Editline::GetLines(int first_line_number, StringList &lines,
                         bool &interrupted) {
   ConfigureEditor(true);
 
-  // Print the initial input lines, then move the cursor back up to the start of
-  // input
+  // Print the initial input lines, then move the cursor back up to the start
+  // of input
   SetBaseLineNumber(first_line_number);
   m_input_lines = std::vector<EditLineStringType>();
   m_input_lines.insert(m_input_lines.begin(), EditLineConstString(""));
diff --git a/source/Host/common/File.cpp b/source/Host/common/File.cpp
index 6ee4e894756b7..3c3d55df22079 100644
--- a/source/Host/common/File.cpp
+++ b/source/Host/common/File.cpp
@@ -100,7 +100,7 @@ int File::GetDescriptor() const {
   // Don't open the file descriptor if we don't need to, just get it from the
   // stream if we have one.
   if (StreamIsValid()) {
-#if defined(LLVM_ON_WIN32)
+#if defined(_WIN32)
     return _fileno(m_stream);
 #else
     return fileno(m_stream);
@@ -126,8 +126,8 @@ FILE *File::GetStream() {
       const char *mode = GetStreamOpenModeFromOptions(m_options);
       if (mode) {
         if (!m_should_close_fd) {
-// We must duplicate the file descriptor if we don't own it because
-// when you call fdopen, the stream will own the fd
+// We must duplicate the file descriptor if we don't own it because when you
+// call fdopen, the stream will own the fd
 #ifdef _WIN32
           m_descriptor = ::_dup(GetDescriptor());
 #else
@@ -139,8 +139,8 @@ FILE *File::GetStream() {
         m_stream =
             llvm::sys::RetryAfterSignal(nullptr, ::fdopen, m_descriptor, mode);
 
-        // If we got a stream, then we own the stream and should no
-        // longer own the descriptor because fclose() will close it for us
+        // If we got a stream, then we own the stream and should no longer own
+        // the descriptor because fclose() will close it for us
 
         if (m_stream) {
           m_own_stream = true;
@@ -315,7 +315,7 @@ Status File::GetFileSpec(FileSpec &file_spec) const {
     if (::fcntl(GetDescriptor(), F_GETPATH, path) == -1)
       error.SetErrorToErrno();
     else
-      file_spec.SetFile(path, false);
+      file_spec.SetFile(path, false, FileSpec::Style::native);
   } else {
     error.SetErrorString("invalid file handle");
   }
@@ -330,7 +330,7 @@ Status File::GetFileSpec(FileSpec &file_spec) const {
       error.SetErrorToErrno();
     else {
       path[len] = '\0';
-      file_spec.SetFile(path, false);
+      file_spec.SetFile(path, false, FileSpec::Style::native);
     }
   }
 #else
diff --git a/source/Host/common/Host.cpp b/source/Host/common/Host.cpp
index 97581185ad9e6..d2848254779e8 100644
--- a/source/Host/common/Host.cpp
+++ b/source/Host/common/Host.cpp
@@ -59,7 +59,6 @@
 #include "lldb/Target/FileAction.h"
 #include "lldb/Target/ProcessLaunchInfo.h"
 #include "lldb/Target/UnixSignals.h"
-#include "lldb/Utility/CleanUp.h"
 #include "lldb/Utility/DataBufferLLVM.h"
 #include "lldb/Utility/FileSpec.h"
 #include "lldb/Utility/Log.h"
@@ -120,9 +119,8 @@ HostThread Host::StartMonitoringChildProcess(
 
 #ifndef __linux__
 //------------------------------------------------------------------
-// Scoped class that will disable thread canceling when it is
-// constructed, and exception safely restore the previous value it
-// when it goes out of scope.
+// Scoped class that will disable thread canceling when it is constructed, and
+// exception safely restore the previous value it when it goes out of scope.
 //------------------------------------------------------------------
 class ScopedPThreadCancelDisabler {
 public:
@@ -271,8 +269,7 @@ static thread_result_t MonitorChildProcessThreadFunction(void *arg) {
                           __FUNCTION__, arg);
             break;
           }
-          // If the callback returns true, it means this process should
-          // exit
+          // If the callback returns true, it means this process should exit
           if (callback_return) {
             if (log)
               log->Printf("%s (arg = %p) thread exiting because callback "
@@ -423,7 +420,7 @@ FileSpec Host::GetModuleFileSpecForHostAddress(const void *host_addr) {
   Dl_info info;
   if (::dladdr(host_addr, &info)) {
     if (info.dli_fname)
-      module_filespec.SetFile(info.dli_fname, true);
+      module_filespec.SetFile(info.dli_fname, true, FileSpec::Style::native);
   }
 #endif
   return module_filespec;
@@ -466,15 +463,17 @@ MonitorShellCommand(std::shared_ptr<ShellInfo> shell_info, lldb::pid_t pid,
 Status Host::RunShellCommand(const char *command, const FileSpec &working_dir,
                              int *status_ptr, int *signo_ptr,
                              std::string *command_output_ptr,
-                             uint32_t timeout_sec, bool run_in_default_shell) {
+                             const Timeout<std::micro> &timeout,
+                             bool run_in_default_shell) {
   return RunShellCommand(Args(command), working_dir, status_ptr, signo_ptr,
-                         command_output_ptr, timeout_sec, run_in_default_shell);
+                         command_output_ptr, timeout, run_in_default_shell);
 }
 
 Status Host::RunShellCommand(const Args &args, const FileSpec &working_dir,
                              int *status_ptr, int *signo_ptr,
                              std::string *command_output_ptr,
-                             uint32_t timeout_sec, bool run_in_default_shell) {
+                             const Timeout<std::micro> &timeout,
+                             bool run_in_default_shell) {
   Status error;
   ProcessLaunchInfo launch_info;
   launch_info.SetArchitecture(HostInfo::GetArchitecture());
@@ -498,11 +497,10 @@ Status Host::RunShellCommand(const Args &args, const FileSpec &working_dir,
   llvm::SmallString<PATH_MAX> output_file_path;
 
   if (command_output_ptr) {
-    // Create a temporary file to get the stdout/stderr and redirect the
-    // output of the command into this file. We will later read this file
-    // if all goes well and fill the data into "command_output_ptr"
-    FileSpec tmpdir_file_spec;
-    if (HostInfo::GetLLDBPath(ePathTypeLLDBTempSystemDir, tmpdir_file_spec)) {
+    // Create a temporary file to get the stdout/stderr and redirect the output
+    // of the command into this file. We will later read this file if all goes
+    // well and fill the data into "command_output_ptr"
+    if (FileSpec tmpdir_file_spec = HostInfo::GetProcessTempDir()) {
       tmpdir_file_spec.AppendPathComponent("lldb-shell-output.%%%%%%");
       llvm::sys::fs::createUniqueFile(tmpdir_file_spec.GetPath(),
                                       output_file_path);
@@ -539,18 +537,14 @@ Status Host::RunShellCommand(const Args &args, const FileSpec &working_dir,
     error.SetErrorString("failed to get process ID");
 
   if (error.Success()) {
-    bool timed_out = false;
-    shell_info_sp->process_reaped.WaitForValueEqualTo(
-        true, std::chrono::seconds(timeout_sec), &timed_out);
-    if (timed_out) {
+    if (!shell_info_sp->process_reaped.WaitForValueEqualTo(true, timeout)) {
       error.SetErrorString("timed out waiting for shell command to complete");
 
       // Kill the process since it didn't complete within the timeout specified
       Kill(pid, SIGKILL);
       // Wait for the monitor callback to get the message
-      timed_out = false;
       shell_info_sp->process_reaped.WaitForValueEqualTo(
-          true, std::chrono::seconds(1), &timed_out);
+          true, std::chrono::seconds(1));
     } else {
       if (status_ptr)
         *status_ptr = shell_info_sp->status;
@@ -581,7 +575,8 @@ Status Host::RunShellCommand(const Args &args, const FileSpec &working_dir,
   return error;
 }
 
-// The functions below implement process launching for non-Apple-based platforms
+// The functions below implement process launching for non-Apple-based
+// platforms
 #if !defined(__APPLE__)
 Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
   std::unique_ptr<ProcessLauncher> delegate_launcher;
@@ -596,8 +591,7 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
   HostProcess process = launcher.LaunchProcess(launch_info, error);
 
   // TODO(zturner): It would be better if the entire HostProcess were returned
-  // instead of writing
-  // it into this structure.
+  // instead of writing it into this structure.
   launch_info.SetProcessID(process.GetProcessId());
 
   return error;
diff --git a/source/Host/common/HostInfoBase.cpp b/source/Host/common/HostInfoBase.cpp
index aff887f9f1d2e..4de6953a91e35 100644
--- a/source/Host/common/HostInfoBase.cpp
+++ b/source/Host/common/HostInfoBase.cpp
@@ -33,19 +33,19 @@ using namespace lldb_private;
 
 namespace {
 //----------------------------------------------------------------------
-// The HostInfoBaseFields is a work around for windows not supporting
-// static variables correctly in a thread safe way. Really each of the
-// variables in HostInfoBaseFields should live in the functions in which
-// they are used and each one should be static, but the work around is
-// in place to avoid this restriction. Ick.
+// The HostInfoBaseFields is a work around for windows not supporting static
+// variables correctly in a thread safe way. Really each of the variables in
+// HostInfoBaseFields should live in the functions in which they are used and
+// each one should be static, but the work around is in place to avoid this
+// restriction. Ick.
 //----------------------------------------------------------------------
 
 struct HostInfoBaseFields {
   ~HostInfoBaseFields() {
     if (m_lldb_process_tmp_dir.Exists()) {
       // Remove the LLDB temporary directory if we have one. Set "recurse" to
-      // true to all files that were created for the LLDB process can be cleaned
-      // up.
+      // true to all files that were created for the LLDB process can be
+      // cleaned up.
       llvm::sys::fs::remove_directories(m_lldb_process_tmp_dir.GetPath());
     }
   }
@@ -58,7 +58,6 @@ struct HostInfoBaseFields {
   FileSpec m_lldb_so_dir;
   FileSpec m_lldb_support_exe_dir;
   FileSpec m_lldb_headers_dir;
-  FileSpec m_lldb_python_dir;
   FileSpec m_lldb_clang_resource_dir;
   FileSpec m_lldb_system_plugin_dir;
   FileSpec m_lldb_user_plugin_dir;
@@ -111,152 +110,88 @@ llvm::Optional<HostInfoBase::ArchitectureKind> HostInfoBase::ParseArchitectureKi
       .Default(llvm::None);
 }
 
-bool HostInfoBase::GetLLDBPath(lldb::PathType type, FileSpec &file_spec) {
-  file_spec.Clear();
+FileSpec HostInfoBase::GetShlibDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success = HostInfo::ComputeSharedLibraryDirectory(g_fields->m_lldb_so_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "shlib dir -> `{0}`", g_fields->m_lldb_so_dir);
+  });
+  return success ? g_fields->m_lldb_so_dir : FileSpec();
+}
 
-#if defined(LLDB_DISABLE_PYTHON)
-  if (type == lldb::ePathTypePythonDir)
-    return false;
-#endif
+FileSpec HostInfoBase::GetSupportExeDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success =
+        HostInfo::ComputeSupportExeDirectory(g_fields->m_lldb_support_exe_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "support exe dir -> `{0}`", g_fields->m_lldb_support_exe_dir);
+  });
+  return success ? g_fields->m_lldb_support_exe_dir : FileSpec();
+}
 
-  FileSpec *result = nullptr;
-  switch (type) {
-  case lldb::ePathTypeLLDBShlibDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success =
-          HostInfo::ComputeSharedLibraryDirectory(g_fields->m_lldb_so_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf("HostInfoBase::GetLLDBPath(ePathTypeLLDBShlibDir) => '%s'",
-                    g_fields->m_lldb_so_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_so_dir;
-  } break;
-  case lldb::ePathTypeSupportExecutableDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeSupportExeDirectory(
-          g_fields->m_lldb_support_exe_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf(
-            "HostInfoBase::GetLLDBPath(ePathTypeSupportExecutableDir) => '%s'",
-            g_fields->m_lldb_support_exe_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_support_exe_dir;
-  } break;
-  case lldb::ePathTypeHeaderDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeHeaderDirectory(g_fields->m_lldb_headers_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf("HostInfoBase::GetLLDBPath(ePathTypeHeaderDir) => '%s'",
-                    g_fields->m_lldb_headers_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_headers_dir;
-  } break;
-  case lldb::ePathTypePythonDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputePythonDirectory(g_fields->m_lldb_python_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf("HostInfoBase::GetLLDBPath(ePathTypePythonDir) => '%s'",
-                    g_fields->m_lldb_python_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_python_dir;
-  } break;
-  case lldb::ePathTypeClangDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success =
-          HostInfo::ComputeClangDirectory(g_fields->m_lldb_clang_resource_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf(
-            "HostInfoBase::GetLLDBPath(ePathTypeClangResourceDir) => '%s'",
-            g_fields->m_lldb_clang_resource_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_clang_resource_dir;
-  } break;
-  case lldb::ePathTypeLLDBSystemPlugins: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeSystemPluginsDirectory(
-          g_fields->m_lldb_system_plugin_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf(
-            "HostInfoBase::GetLLDBPath(ePathTypeLLDBSystemPlugins) => '%s'",
-            g_fields->m_lldb_system_plugin_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_system_plugin_dir;
-  } break;
-  case lldb::ePathTypeLLDBUserPlugins: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeUserPluginsDirectory(
-          g_fields->m_lldb_user_plugin_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf(
-            "HostInfoBase::GetLLDBPath(ePathTypeLLDBUserPlugins) => '%s'",
-            g_fields->m_lldb_user_plugin_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_user_plugin_dir;
-  } break;
-  case lldb::ePathTypeLLDBTempSystemDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeProcessTempFileDirectory(
-          g_fields->m_lldb_process_tmp_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf(
-            "HostInfoBase::GetLLDBPath(ePathTypeLLDBTempSystemDir) => '%s'",
-            g_fields->m_lldb_process_tmp_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_process_tmp_dir;
-  } break;
-  case lldb::ePathTypeGlobalLLDBTempSystemDir: {
-    static llvm::once_flag g_once_flag;
-    static bool success = false;
-    llvm::call_once(g_once_flag, []() {
-      success = HostInfo::ComputeGlobalTempFileDirectory(
-          g_fields->m_lldb_global_tmp_dir);
-      Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
-      if (log)
-        log->Printf("HostInfoBase::GetLLDBPath("
-                    "ePathTypeGlobalLLDBTempSystemDir) => '%s'",
-                    g_fields->m_lldb_global_tmp_dir.GetPath().c_str());
-    });
-    if (success)
-      result = &g_fields->m_lldb_global_tmp_dir;
-  } break;
-  }
+FileSpec HostInfoBase::GetHeaderDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success = HostInfo::ComputeHeaderDirectory(g_fields->m_lldb_headers_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "header dir -> `{0}`", g_fields->m_lldb_headers_dir);
+  });
+  return success ? g_fields->m_lldb_headers_dir : FileSpec();
+}
 
-  if (!result)
-    return false;
-  file_spec = *result;
-  return true;
+FileSpec HostInfoBase::GetSystemPluginDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success = HostInfo::ComputeSystemPluginsDirectory(
+        g_fields->m_lldb_system_plugin_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "system plugin dir -> `{0}`",
+             g_fields->m_lldb_system_plugin_dir);
+  });
+  return success ? g_fields->m_lldb_system_plugin_dir : FileSpec();
+}
+
+FileSpec HostInfoBase::GetUserPluginDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success =
+        HostInfo::ComputeUserPluginsDirectory(g_fields->m_lldb_user_plugin_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "user plugin dir -> `{0}`", g_fields->m_lldb_user_plugin_dir);
+  });
+  return success ? g_fields->m_lldb_user_plugin_dir : FileSpec();
+}
+
+FileSpec HostInfoBase::GetProcessTempDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success = HostInfo::ComputeProcessTempFileDirectory(
+        g_fields->m_lldb_process_tmp_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "process temp dir -> `{0}`",
+             g_fields->m_lldb_process_tmp_dir);
+  });
+  return success ? g_fields->m_lldb_process_tmp_dir : FileSpec();
+}
+
+FileSpec HostInfoBase::GetGlobalTempDir() {
+  static llvm::once_flag g_once_flag;
+  static bool success = false;
+  llvm::call_once(g_once_flag, []() {
+    success = HostInfo::ComputeGlobalTempFileDirectory(
+        g_fields->m_lldb_global_tmp_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    LLDB_LOG(log, "global temp dir -> `{0}`", g_fields->m_lldb_global_tmp_dir);
+  });
+  return success ? g_fields->m_lldb_global_tmp_dir : FileSpec();
 }
 
 ArchSpec HostInfoBase::GetAugmentedArchSpec(llvm::StringRef triple) {
@@ -282,14 +217,12 @@ ArchSpec HostInfoBase::GetAugmentedArchSpec(llvm::StringRef triple) {
 
 bool HostInfoBase::ComputeSharedLibraryDirectory(FileSpec &file_spec) {
   // To get paths related to LLDB we get the path to the executable that
-  // contains this function. On MacOSX this will be "LLDB.framework/.../LLDB",
-  // on linux this is assumed to be the "lldb" main executable. If LLDB on
-  // linux is actually in a shared library (liblldb.so) then this function will
-  // need to be modified to "do the right thing".
+  // contains this function. On MacOSX this will be "LLDB.framework/.../LLDB".
+  // On other posix systems, we will get .../lib(64|32)?/liblldb.so.
 
-  FileSpec lldb_file_spec(
-      Host::GetModuleFileSpecForHostAddress(reinterpret_cast<void *>(
-          reinterpret_cast<intptr_t>(HostInfoBase::GetLLDBPath))));
+  FileSpec lldb_file_spec(Host::GetModuleFileSpecForHostAddress(
+      reinterpret_cast<void *>(reinterpret_cast<intptr_t>(
+          HostInfoBase::ComputeSharedLibraryDirectory))));
 
   // This is necessary because when running the testsuite the shlib might be a
   // symbolic link inside the Python resource dir.
@@ -302,7 +235,8 @@ bool HostInfoBase::ComputeSharedLibraryDirectory(FileSpec &file_spec) {
 }
 
 bool HostInfoBase::ComputeSupportExeDirectory(FileSpec &file_spec) {
-  return GetLLDBPath(lldb::ePathTypeLLDBShlibDir, file_spec);
+  file_spec = GetShlibDir();
+  return bool(file_spec);
 }
 
 bool HostInfoBase::ComputeProcessTempFileDirectory(FileSpec &file_spec) {
@@ -353,11 +287,9 @@ bool HostInfoBase::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
   return false;
 }
 
-bool HostInfoBase::ComputeClangDirectory(FileSpec &file_spec) { return false; }
-
 bool HostInfoBase::ComputeUserPluginsDirectory(FileSpec &file_spec) {
-  // TODO(zturner): Figure out how to compute the user plugins directory for all
-  // platforms.
+  // TODO(zturner): Figure out how to compute the user plugins directory for
+  // all platforms.
   return false;
 }
 
@@ -375,6 +307,7 @@ void HostInfoBase::ComputeHostArchitectureSupport(ArchSpec &arch_32,
 
   case llvm::Triple::aarch64:
   case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
   case llvm::Triple::x86_64:
     arch_64.SetTriple(triple);
     arch_32.SetTriple(triple.get32BitArchVariant());
diff --git a/source/Host/common/MainLoop.cpp b/source/Host/common/MainLoop.cpp
index 6cbb5a8425623..65158c942934f 100644
--- a/source/Host/common/MainLoop.cpp
+++ b/source/Host/common/MainLoop.cpp
@@ -26,7 +26,7 @@
 
 #if HAVE_SYS_EVENT_H
 #include <sys/event.h>
-#elif defined(LLVM_ON_WIN32)
+#elif defined(_WIN32)
 #include <winsock2.h>
 #elif defined(__ANDROID__)
 #include <sys/syscall.h>
@@ -34,14 +34,14 @@
 #include <poll.h>
 #endif
 
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 #define POLL WSAPoll
 #else
 #define POLL poll
 #endif
 
 #if SIGNAL_POLLING_UNSUPPORTED
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 typedef int sigset_t;
 typedef int siginfo_t;
 #endif
@@ -209,8 +209,8 @@ Status MainLoop::RunImpl::Poll() {
 
 void MainLoop::RunImpl::ProcessEvents() {
 #ifdef __ANDROID__
-  // Collect first all readable file descriptors into a separate vector and then
-  // iterate over it to invoke callbacks. Iterating directly over
+  // Collect first all readable file descriptors into a separate vector and
+  // then iterate over it to invoke callbacks. Iterating directly over
   // loop.m_read_fds is not possible because the callbacks can modify the
   // container which could invalidate the iterator.
   std::vector<IOObject::WaitableHandle> fds;
@@ -262,7 +262,7 @@ MainLoop::~MainLoop() {
 MainLoop::ReadHandleUP MainLoop::RegisterReadObject(const IOObjectSP &object_sp,
                                                     const Callback &callback,
                                                     Status &error) {
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   if (object_sp->GetFdType() != IOObject:: eFDTypeSocket) {
     error.SetErrorString("MainLoop: non-socket types unsupported on Windows");
     return nullptr;
@@ -285,8 +285,7 @@ MainLoop::ReadHandleUP MainLoop::RegisterReadObject(const IOObjectSP &object_sp,
 }
 
 // We shall block the signal, then install the signal handler. The signal will
-// be unblocked in
-// the Run() function to check for signal delivery.
+// be unblocked in the Run() function to check for signal delivery.
 MainLoop::SignalHandleUP
 MainLoop::RegisterSignal(int signo, const Callback &callback, Status &error) {
 #ifdef SIGNAL_POLLING_UNSUPPORTED
@@ -321,9 +320,9 @@ MainLoop::RegisterSignal(int signo, const Callback &callback, Status &error) {
   assert(ret == 0);
 #endif
 
-  // If we're using kqueue, the signal needs to be unblocked in order to recieve
-  // it. If using pselect/ppoll, we need to block it, and later unblock it as a
-  // part of the system call.
+  // If we're using kqueue, the signal needs to be unblocked in order to
+  // recieve it. If using pselect/ppoll, we need to block it, and later unblock
+  // it as a part of the system call.
   ret = pthread_sigmask(HAVE_SYS_EVENT_H ? SIG_UNBLOCK : SIG_BLOCK,
                         &new_action.sa_mask, &old_set);
   assert(ret == 0 && "pthread_sigmask failed");
diff --git a/source/Host/common/MonitoringProcessLauncher.cpp b/source/Host/common/MonitoringProcessLauncher.cpp
index f1fcd0b44c150..76c11454f573c 100644
--- a/source/Host/common/MonitoringProcessLauncher.cpp
+++ b/source/Host/common/MonitoringProcessLauncher.cpp
@@ -8,11 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/MonitoringProcessLauncher.h"
-#include "lldb/Core/Module.h"
-#include "lldb/Core/ModuleSpec.h"
 #include "lldb/Host/HostProcess.h"
-#include "lldb/Target/Platform.h"
-#include "lldb/Target/Process.h"
 #include "lldb/Target/ProcessLaunchInfo.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/Status.h"
@@ -32,36 +28,23 @@ MonitoringProcessLauncher::LaunchProcess(const ProcessLaunchInfo &launch_info,
   ProcessLaunchInfo resolved_info(launch_info);
 
   error.Clear();
-  char exe_path[PATH_MAX];
-
-  PlatformSP host_platform_sp(Platform::GetHostPlatform());
-
-  const ArchSpec &arch_spec = resolved_info.GetArchitecture();
 
   FileSpec exe_spec(resolved_info.GetExecutableFile());
 
   llvm::sys::fs::file_status stats;
   status(exe_spec.GetPath(), stats);
-  if (!is_regular_file(stats)) {
-    ModuleSpec module_spec(exe_spec, arch_spec);
-    lldb::ModuleSP exe_module_sp;
-    error =
-        host_platform_sp->ResolveExecutable(module_spec, exe_module_sp, NULL);
-
-    if (error.Fail())
-      return HostProcess();
-
-    if (exe_module_sp) {
-      exe_spec = exe_module_sp->GetFileSpec();
-      status(exe_spec.GetPath(), stats);
-    }
+  if (!exists(stats)) {
+    exe_spec.ResolvePath();
+    status(exe_spec.GetPath(), stats);
+  }
+  if (!exists(stats)) {
+    exe_spec.ResolveExecutableLocation();
+    status(exe_spec.GetPath(), stats);
   }
 
-  if (exists(stats)) {
-    exe_spec.GetPath(exe_path, sizeof(exe_path));
-  } else {
-    resolved_info.GetExecutableFile().GetPath(exe_path, sizeof(exe_path));
-    error.SetErrorStringWithFormat("executable doesn't exist: '%s'", exe_path);
+  if (!exists(stats)) {
+    error.SetErrorStringWithFormatv("executable doesn't exist: '{0}'",
+                                    exe_spec);
     return HostProcess();
   }
 
@@ -74,18 +57,9 @@ MonitoringProcessLauncher::LaunchProcess(const ProcessLaunchInfo &launch_info,
   if (process.GetProcessId() != LLDB_INVALID_PROCESS_ID) {
     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 
-    Host::MonitorChildProcessCallback callback =
-        launch_info.GetMonitorProcessCallback();
-
-    bool monitor_signals = false;
-    if (callback) {
-      // If the ProcessLaunchInfo specified a callback, use that.
-      monitor_signals = launch_info.GetMonitorSignals();
-    } else {
-      callback = Process::SetProcessExitStatus;
-    }
-
-    process.StartMonitoring(callback, monitor_signals);
+    assert(launch_info.GetMonitorProcessCallback());
+    process.StartMonitoring(launch_info.GetMonitorProcessCallback(),
+                            launch_info.GetMonitorSignals());
     if (log)
       log->PutCString("started monitoring child process.");
   } else {
diff --git a/source/Host/common/NativeBreakpointList.cpp b/source/Host/common/NativeBreakpointList.cpp
index ce5eb94a8d1fb..cfcbe0831064b 100644
--- a/source/Host/common/NativeBreakpointList.cpp
+++ b/source/Host/common/NativeBreakpointList.cpp
@@ -104,8 +104,8 @@ Status NativeBreakpointList::DecRef(lldb::addr_t addr) {
     return error;
   }
 
-  // Breakpoint has no more references.  Disable it if it's not
-  // already disabled.
+  // Breakpoint has no more references.  Disable it if it's not already
+  // disabled.
   if (log)
     log->Printf("NativeBreakpointList::%s addr = 0x%" PRIx64
                 " -- removing due to no remaining references",
diff --git a/source/Host/common/NativeProcessProtocol.cpp b/source/Host/common/NativeProcessProtocol.cpp
index 1fcb11b8b6f5d..3e8648f814739 100644
--- a/source/Host/common/NativeProcessProtocol.cpp
+++ b/source/Host/common/NativeProcessProtocol.cpp
@@ -8,14 +8,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/common/NativeProcessProtocol.h"
-#include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/State.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/common/NativeRegisterContext.h"
 #include "lldb/Host/common/NativeThreadProtocol.h"
 #include "lldb/Host/common/SoftwareBreakpoint.h"
-#include "lldb/Symbol/ObjectFile.h"
-#include "lldb/Target/Process.h"
 #include "lldb/Utility/LLDBAssert.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/lldb-enumerations.h"
@@ -139,29 +136,28 @@ NativeProcessProtocol::GetHardwareDebugSupportInfo() const {
 Status NativeProcessProtocol::SetWatchpoint(lldb::addr_t addr, size_t size,
                                             uint32_t watch_flags,
                                             bool hardware) {
-  // This default implementation assumes setting the watchpoint for
-  // the process will require setting the watchpoint for each of the
-  // threads.  Furthermore, it will track watchpoints set for the
-  // process and will add them to each thread that is attached to
-  // via the (FIXME implement) OnThreadAttached () method.
+  // This default implementation assumes setting the watchpoint for the process
+  // will require setting the watchpoint for each of the threads.  Furthermore,
+  // it will track watchpoints set for the process and will add them to each
+  // thread that is attached to via the (FIXME implement) OnThreadAttached ()
+  // method.
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 
   // Update the thread list
   UpdateThreads();
 
-  // Keep track of the threads we successfully set the watchpoint
-  // for.  If one of the thread watchpoint setting operations fails,
-  // back off and remove the watchpoint for all the threads that
-  // were successfully set so we get back to a consistent state.
+  // Keep track of the threads we successfully set the watchpoint for.  If one
+  // of the thread watchpoint setting operations fails, back off and remove the
+  // watchpoint for all the threads that were successfully set so we get back
+  // to a consistent state.
   std::vector<NativeThreadProtocol *> watchpoint_established_threads;
 
-  // Tell each thread to set a watchpoint.  In the event that
-  // hardware watchpoints are requested but the SetWatchpoint fails,
-  // try to set a software watchpoint as a fallback.  It's
-  // conceivable that if there are more threads than hardware
-  // watchpoints available, some of the threads will fail to set
-  // hardware watchpoints while software ones may be available.
+  // Tell each thread to set a watchpoint.  In the event that hardware
+  // watchpoints are requested but the SetWatchpoint fails, try to set a
+  // software watchpoint as a fallback.  It's conceivable that if there are
+  // more threads than hardware watchpoints available, some of the threads will
+  // fail to set hardware watchpoints while software ones may be available.
   std::lock_guard<std::recursive_mutex> guard(m_threads_mutex);
   for (const auto &thread : m_threads) {
     assert(thread && "thread list should not have a NULL thread!");
@@ -169,8 +165,8 @@ Status NativeProcessProtocol::SetWatchpoint(lldb::addr_t addr, size_t size,
     Status thread_error =
         thread->SetWatchpoint(addr, size, watch_flags, hardware);
     if (thread_error.Fail() && hardware) {
-      // Try software watchpoints since we failed on hardware watchpoint setting
-      // and we may have just run out of hardware watchpoints.
+      // Try software watchpoints since we failed on hardware watchpoint
+      // setting and we may have just run out of hardware watchpoints.
       thread_error = thread->SetWatchpoint(addr, size, watch_flags, false);
       if (thread_error.Success())
         LLDB_LOG(log,
@@ -178,13 +174,12 @@ Status NativeProcessProtocol::SetWatchpoint(lldb::addr_t addr, size_t size,
     }
 
     if (thread_error.Success()) {
-      // Remember that we set this watchpoint successfully in
-      // case we need to clear it later.
+      // Remember that we set this watchpoint successfully in case we need to
+      // clear it later.
       watchpoint_established_threads.push_back(thread.get());
     } else {
-      // Unset the watchpoint for each thread we successfully
-      // set so that we get back to a consistent state of "not
-      // set" for the watchpoint.
+      // Unset the watchpoint for each thread we successfully set so that we
+      // get back to a consistent state of "not set" for the watchpoint.
       for (auto unwatch_thread_sp : watchpoint_established_threads) {
         Status remove_error = unwatch_thread_sp->RemoveWatchpoint(addr);
         if (remove_error.Fail())
@@ -210,9 +205,9 @@ Status NativeProcessProtocol::RemoveWatchpoint(lldb::addr_t addr) {
 
     const Status thread_error = thread->RemoveWatchpoint(addr);
     if (thread_error.Fail()) {
-      // Keep track of the first thread error if any threads
-      // fail. We want to try to remove the watchpoint from
-      // every thread, though, even if one or more have errors.
+      // Keep track of the first thread error if any threads fail. We want to
+      // try to remove the watchpoint from every thread, though, even if one or
+      // more have errors.
       if (!overall_error.Fail())
         overall_error = thread_error;
     }
@@ -228,9 +223,9 @@ NativeProcessProtocol::GetHardwareBreakpointMap() const {
 
 Status NativeProcessProtocol::SetHardwareBreakpoint(lldb::addr_t addr,
                                                     size_t size) {
-  // This default implementation assumes setting a hardware breakpoint for
-  // this process will require setting same hardware breakpoint for each
-  // of its existing threads. New thread will do the same once created.
+  // This default implementation assumes setting a hardware breakpoint for this
+  // process will require setting same hardware breakpoint for each of its
+  // existing threads. New thread will do the same once created.
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 
   // Update the thread list
@@ -256,13 +251,13 @@ Status NativeProcessProtocol::SetHardwareBreakpoint(lldb::addr_t addr,
 
     Status thread_error = thread->SetHardwareBreakpoint(addr, size);
     if (thread_error.Success()) {
-      // Remember that we set this breakpoint successfully in
-      // case we need to clear it later.
+      // Remember that we set this breakpoint successfully in case we need to
+      // clear it later.
       breakpoint_established_threads.push_back(thread.get());
     } else {
-      // Unset the breakpoint for each thread we successfully
-      // set so that we get back to a consistent state of "not
-      // set" for this hardware breakpoint.
+      // Unset the breakpoint for each thread we successfully set so that we
+      // get back to a consistent state of "not set" for this hardware
+      // breakpoint.
       for (auto rollback_thread_sp : breakpoint_established_threads) {
         Status remove_error =
             rollback_thread_sp->RemoveHardwareBreakpoint(addr);
@@ -322,8 +317,8 @@ bool NativeProcessProtocol::UnregisterNativeDelegate(
       remove(m_delegates.begin(), m_delegates.end(), &native_delegate),
       m_delegates.end());
 
-  // We removed the delegate if the count of delegates shrank after
-  // removing all copies of the given native_delegate from the vector.
+  // We removed the delegate if the count of delegates shrank after removing
+  // all copies of the given native_delegate from the vector.
   return m_delegates.size() < initial_size;
 }
 
@@ -412,8 +407,8 @@ void NativeProcessProtocol::SetState(lldb::StateType state,
 
     // Give process a chance to do any stop id bump processing, such as
     // clearing cached data that is invalidated each time the process runs.
-    // Note if/when we support some threads running, we'll end up needing
-    // to manage this per thread and per process.
+    // Note if/when we support some threads running, we'll end up needing to
+    // manage this per thread and per process.
     DoStopIDBumped(m_stop_id);
   }
 
@@ -431,26 +426,4 @@ void NativeProcessProtocol::DoStopIDBumped(uint32_t /* newBumpId */) {
   // Default implementation does nothing.
 }
 
-Status NativeProcessProtocol::ResolveProcessArchitecture(lldb::pid_t pid,
-                                                         ArchSpec &arch) {
-  // Grab process info for the running process.
-  ProcessInstanceInfo process_info;
-  if (!Host::GetProcessInfo(pid, process_info))
-    return Status("failed to get process info");
-
-  // Resolve the executable module.
-  ModuleSpecList module_specs;
-  if (!ObjectFile::GetModuleSpecifications(process_info.GetExecutableFile(), 0,
-                                           0, module_specs))
-    return Status("failed to get module specifications");
-  lldbassert(module_specs.GetSize() == 1);
-
-  arch = module_specs.GetModuleSpecRefAtIndex(0).GetArchitecture();
-  if (arch.IsValid())
-    return Status();
-  else
-    return Status(
-        "failed to retrieve a valid architecture from the exe module");
-}
-
 NativeProcessProtocol::Factory::~Factory() = default;
diff --git a/source/Host/common/NativeRegisterContext.cpp b/source/Host/common/NativeRegisterContext.cpp
index 60eaebdc94cd2..49b8284da9703 100644
--- a/source/Host/common/NativeRegisterContext.cpp
+++ b/source/Host/common/NativeRegisterContext.cpp
@@ -28,13 +28,12 @@ NativeRegisterContext::NativeRegisterContext(NativeThreadProtocol &thread)
 NativeRegisterContext::~NativeRegisterContext() {}
 
 // FIXME revisit invalidation, process stop ids, etc.  Right now we don't
-// support caching in NativeRegisterContext.  We can do this later by
-// utilizing NativeProcessProtocol::GetStopID () and adding a stop id to
+// support caching in NativeRegisterContext.  We can do this later by utilizing
+// NativeProcessProtocol::GetStopID () and adding a stop id to
 // NativeRegisterContext.
 
 // void
-// NativeRegisterContext::InvalidateIfNeeded (bool force)
-// {
+// NativeRegisterContext::InvalidateIfNeeded (bool force) {
 //     ProcessSP process_sp (m_thread.GetProcess());
 //     bool invalidate = force;
 //     uint32_t process_stop_id = UINT32_MAX;
@@ -365,8 +364,8 @@ Status NativeRegisterContext::ReadRegisterValueFromMemory(
   // We now have a memory buffer that contains the part or all of the register
   // value. Set the register value using this memory data.
   // TODO: we might need to add a parameter to this function in case the byte
-  // order of the memory data doesn't match the process. For now we are assuming
-  // they are the same.
+  // order of the memory data doesn't match the process. For now we are
+  // assuming they are the same.
   reg_value.SetFromMemoryData(reg_info, src, src_len, process.GetByteOrder(),
                               error);
 
@@ -385,8 +384,7 @@ Status NativeRegisterContext::WriteRegisterValueToMemory(
 
   // TODO: we might need to add a parameter to this function in case the byte
   // order of the memory data doesn't match the process. For now we are
-  // assuming
-  // they are the same.
+  // assuming they are the same.
   const size_t bytes_copied = reg_value.GetAsMemoryData(
       reg_info, dst, dst_len, process.GetByteOrder(), error);
 
diff --git a/source/Host/common/NativeThreadProtocol.cpp b/source/Host/common/NativeThreadProtocol.cpp
index 3f3915e006da6..0c648e40eb5c6 100644
--- a/source/Host/common/NativeThreadProtocol.cpp
+++ b/source/Host/common/NativeThreadProtocol.cpp
@@ -19,36 +19,3 @@ using namespace lldb_private;
 NativeThreadProtocol::NativeThreadProtocol(NativeProcessProtocol &process,
                                            lldb::tid_t tid)
     : m_process(process), m_tid(tid) {}
-
-Status NativeThreadProtocol::ReadRegister(uint32_t reg,
-                                          RegisterValue &reg_value) {
-  NativeRegisterContext &register_context = GetRegisterContext();
-
-  const RegisterInfo *const reg_info =
-      register_context.GetRegisterInfoAtIndex(reg);
-  if (!reg_info)
-    return Status("no register info for reg num %" PRIu32, reg);
-
-  return register_context.ReadRegister(reg_info, reg_value);
-  ;
-}
-
-Status NativeThreadProtocol::WriteRegister(uint32_t reg,
-                                           const RegisterValue &reg_value) {
-  NativeRegisterContext& register_context = GetRegisterContext();
-
-  const RegisterInfo *const reg_info =
-      register_context.GetRegisterInfoAtIndex(reg);
-  if (!reg_info)
-    return Status("no register info for reg num %" PRIu32, reg);
-
-  return register_context.WriteRegister(reg_info, reg_value);
-}
-
-Status NativeThreadProtocol::SaveAllRegisters(lldb::DataBufferSP &data_sp) {
-  return GetRegisterContext().WriteAllRegisterValues(data_sp);
-}
-
-Status NativeThreadProtocol::RestoreAllRegisters(lldb::DataBufferSP &data_sp) {
-  return GetRegisterContext().ReadAllRegisterValues(data_sp);
-}
diff --git a/source/Host/common/PseudoTerminal.cpp b/source/Host/common/PseudoTerminal.cpp
index 9657cb6523dce..c9b290078e182 100644
--- a/source/Host/common/PseudoTerminal.cpp
+++ b/source/Host/common/PseudoTerminal.cpp
@@ -35,10 +35,10 @@ PseudoTerminal::PseudoTerminal()
 //----------------------------------------------------------------------
 // Destructor
 //
-// The destructor will close the master and slave file descriptors
-// if they are valid and ownership has not been released using the
-// ReleaseMasterFileDescriptor() or the ReleaseSaveFileDescriptor()
-// member functions.
+// The destructor will close the master and slave file descriptors if they are
+// valid and ownership has not been released using the
+// ReleaseMasterFileDescriptor() or the ReleaseSaveFileDescriptor() member
+// functions.
 //----------------------------------------------------------------------
 PseudoTerminal::~PseudoTerminal() {
   CloseMasterFileDescriptor();
@@ -66,15 +66,14 @@ void PseudoTerminal::CloseSlaveFileDescriptor() {
 }
 
 //----------------------------------------------------------------------
-// Open the first available pseudo terminal with OFLAG as the
-// permissions. The file descriptor is stored in this object and can
-// be accessed with the MasterFileDescriptor() accessor. The
-// ownership of the master file descriptor can be released using
-// the ReleaseMasterFileDescriptor() accessor. If this object has
-// a valid master files descriptor when its destructor is called, it
-// will close the master file descriptor, therefore clients must
-// call ReleaseMasterFileDescriptor() if they wish to use the master
-// file descriptor after this object is out of scope or destroyed.
+// Open the first available pseudo terminal with OFLAG as the permissions. The
+// file descriptor is stored in this object and can be accessed with the
+// MasterFileDescriptor() accessor. The ownership of the master file descriptor
+// can be released using the ReleaseMasterFileDescriptor() accessor. If this
+// object has a valid master files descriptor when its destructor is called, it
+// will close the master file descriptor, therefore clients must call
+// ReleaseMasterFileDescriptor() if they wish to use the master file descriptor
+// after this object is out of scope or destroyed.
 //
 // RETURNS:
 //  True when successful, false indicating an error occurred.
@@ -118,12 +117,12 @@ bool PseudoTerminal::OpenFirstAvailableMaster(int oflag, char *error_str,
 }
 
 //----------------------------------------------------------------------
-// Open the slave pseudo terminal for the current master pseudo
-// terminal. A master pseudo terminal should already be valid prior to
-// calling this function (see OpenFirstAvailableMaster()).
-// The file descriptor is stored this object's member variables and can
-// be accessed via the GetSlaveFileDescriptor(), or released using the
-// ReleaseSlaveFileDescriptor() member function.
+// Open the slave pseudo terminal for the current master pseudo terminal. A
+// master pseudo terminal should already be valid prior to calling this
+// function (see OpenFirstAvailableMaster()). The file descriptor is stored
+// this object's member variables and can be accessed via the
+// GetSlaveFileDescriptor(), or released using the ReleaseSlaveFileDescriptor()
+// member function.
 //
 // RETURNS:
 //  True when successful, false indicating an error occurred.
@@ -152,8 +151,8 @@ bool PseudoTerminal::OpenSlave(int oflag, char *error_str, size_t error_len) {
 }
 
 //----------------------------------------------------------------------
-// Get the name of the slave pseudo terminal. A master pseudo terminal
-// should already be valid prior to calling this function (see
+// Get the name of the slave pseudo terminal. A master pseudo terminal should
+// already be valid prior to calling this function (see
 // OpenFirstAvailableMaster()).
 //
 // RETURNS:
@@ -185,18 +184,16 @@ const char *PseudoTerminal::GetSlaveName(char *error_str,
 // Fork a child process and have its stdio routed to a pseudo terminal.
 //
 // In the parent process when a valid pid is returned, the master file
-// descriptor can be used as a read/write access to stdio of the
-// child process.
+// descriptor can be used as a read/write access to stdio of the child process.
 //
-// In the child process the stdin/stdout/stderr will already be routed
-// to the slave pseudo terminal and the master file descriptor will be
-// closed as it is no longer needed by the child process.
+// In the child process the stdin/stdout/stderr will already be routed to the
+// slave pseudo terminal and the master file descriptor will be closed as it is
+// no longer needed by the child process.
 //
-// This class will close the file descriptors for the master/slave
-// when the destructor is called, so be sure to call
-// ReleaseMasterFileDescriptor() or ReleaseSlaveFileDescriptor() if any
-// file descriptors are going to be used past the lifespan of this
-// object.
+// This class will close the file descriptors for the master/slave when the
+// destructor is called, so be sure to call ReleaseMasterFileDescriptor() or
+// ReleaseSlaveFileDescriptor() if any file descriptors are going to be used
+// past the lifespan of this object.
 //
 // RETURNS:
 //  in the parent process: the pid of the child, or -1 if fork fails
@@ -261,49 +258,47 @@ lldb::pid_t PseudoTerminal::Fork(char *error_str, size_t error_len) {
 }
 
 //----------------------------------------------------------------------
-// The master file descriptor accessor. This object retains ownership
-// of the master file descriptor when this accessor is used. Use
-// ReleaseMasterFileDescriptor() if you wish this object to release
-// ownership of the master file descriptor.
+// The master file descriptor accessor. This object retains ownership of the
+// master file descriptor when this accessor is used. Use
+// ReleaseMasterFileDescriptor() if you wish this object to release ownership
+// of the master file descriptor.
 //
-// Returns the master file descriptor, or -1 if the master file
-// descriptor is not currently valid.
+// Returns the master file descriptor, or -1 if the master file descriptor is
+// not currently valid.
 //----------------------------------------------------------------------
 int PseudoTerminal::GetMasterFileDescriptor() const { return m_master_fd; }
 
 //----------------------------------------------------------------------
 // The slave file descriptor accessor.
 //
-// Returns the slave file descriptor, or -1 if the slave file
-// descriptor is not currently valid.
+// Returns the slave file descriptor, or -1 if the slave file descriptor is not
+// currently valid.
 //----------------------------------------------------------------------
 int PseudoTerminal::GetSlaveFileDescriptor() const { return m_slave_fd; }
 
 //----------------------------------------------------------------------
-// Release ownership of the master pseudo terminal file descriptor
-// without closing it. The destructor for this class will close the
-// master file descriptor if the ownership isn't released using this
-// call and the master file descriptor has been opened.
+// Release ownership of the master pseudo terminal file descriptor without
+// closing it. The destructor for this class will close the master file
+// descriptor if the ownership isn't released using this call and the master
+// file descriptor has been opened.
 //----------------------------------------------------------------------
 int PseudoTerminal::ReleaseMasterFileDescriptor() {
-  // Release ownership of the master pseudo terminal file
-  // descriptor without closing it. (the destructor for this
-  // class will close it otherwise!)
+  // Release ownership of the master pseudo terminal file descriptor without
+  // closing it. (the destructor for this class will close it otherwise!)
   int fd = m_master_fd;
   m_master_fd = invalid_fd;
   return fd;
 }
 
 //----------------------------------------------------------------------
-// Release ownership of the slave pseudo terminal file descriptor
-// without closing it. The destructor for this class will close the
-// slave file descriptor if the ownership isn't released using this
-// call and the slave file descriptor has been opened.
+// Release ownership of the slave pseudo terminal file descriptor without
+// closing it. The destructor for this class will close the slave file
+// descriptor if the ownership isn't released using this call and the slave
+// file descriptor has been opened.
 //----------------------------------------------------------------------
 int PseudoTerminal::ReleaseSlaveFileDescriptor() {
-  // Release ownership of the slave pseudo terminal file
-  // descriptor without closing it (the destructor for this
-  // class will close it otherwise!)
+  // Release ownership of the slave pseudo terminal file descriptor without
+  // closing it (the destructor for this class will close it otherwise!)
   int fd = m_slave_fd;
   m_slave_fd = invalid_fd;
   return fd;
diff --git a/source/Host/common/Socket.cpp b/source/Host/common/Socket.cpp
index 4c23e4eb560c4..875291bc115f8 100644
--- a/source/Host/common/Socket.cpp
+++ b/source/Host/common/Socket.cpp
@@ -160,18 +160,17 @@ Status Socket::TcpListen(llvm::StringRef host_and_port,
 
   error = listen_socket->Listen(host_and_port, backlog);
   if (error.Success()) {
-    // We were asked to listen on port zero which means we
-    // must now read the actual port that was given to us
-    // as port zero is a special code for "find an open port
-    // for me".
+    // We were asked to listen on port zero which means we must now read the
+    // actual port that was given to us as port zero is a special code for
+    // "find an open port for me".
     if (port == 0)
       port = listen_socket->GetLocalPortNumber();
 
-    // Set the port predicate since when doing a listen://<host>:<port>
-    // it often needs to accept the incoming connection which is a blocking
-    // system call. Allowing access to the bound port using a predicate allows
-    // us to wait for the port predicate to be set to a non-zero value from
-    // another thread in an efficient manor.
+    // Set the port predicate since when doing a listen://<host>:<port> it
+    // often needs to accept the incoming connection which is a blocking system
+    // call. Allowing access to the bound port using a predicate allows us to
+    // wait for the port predicate to be set to a non-zero value from another
+    // thread in an efficient manor.
     if (predicate)
       predicate->SetValue(port, eBroadcastAlways);
     socket = listen_socket.release();
@@ -282,8 +281,7 @@ bool Socket::DecodeHostAndPort(llvm::StringRef host_and_port,
   }
 
   // If this was unsuccessful, then check if it's simply a signed 32-bit
-  // integer, representing
-  // a port with an empty host.
+  // integer, representing a port with an empty host.
   host_str.clear();
   port_str.clear();
   bool ok = false;
@@ -436,8 +434,8 @@ NativeSocket Socket::AcceptSocket(NativeSocket sockfd, struct sockaddr *addr,
   error.Clear();
 #if defined(ANDROID_USE_ACCEPT_WORKAROUND)
   // Hack:
-  // This enables static linking lldb-server to an API 21 libc, but still having
-  // it run on older devices. It is necessary because API 21 libc's
+  // This enables static linking lldb-server to an API 21 libc, but still
+  // having it run on older devices. It is necessary because API 21 libc's
   // implementation of accept() uses the accept4 syscall(), which is not
   // available in older kernels. Using an older libc would fix this issue, but
   // introduce other ones, as the old libraries were quite buggy.
diff --git a/source/Host/common/SoftwareBreakpoint.cpp b/source/Host/common/SoftwareBreakpoint.cpp
index 14dbafd94c039..353dadf6ce6d6 100644
--- a/source/Host/common/SoftwareBreakpoint.cpp
+++ b/source/Host/common/SoftwareBreakpoint.cpp
@@ -17,9 +17,8 @@
 
 using namespace lldb_private;
 
-// -------------------------------------------------------------------
-// static members
-// -------------------------------------------------------------------
+// ------------------------------------------------------------------- static
+// members -------------------------------------------------------------------
 
 Status SoftwareBreakpoint::CreateSoftwareBreakpoint(
     NativeProcessProtocol &process, lldb::addr_t addr, size_t size_hint,
@@ -34,8 +33,7 @@ Status SoftwareBreakpoint::CreateSoftwareBreakpoint(
                   __FUNCTION__);
 
   // Ask the NativeProcessProtocol subclass to fill in the correct software
-  // breakpoint
-  // trap for the breakpoint site.
+  // breakpoint trap for the breakpoint site.
   size_t bp_opcode_size = 0;
   const uint8_t *bp_opcode_bytes = NULL;
   Status error = process.GetSoftwareBreakpointTrapOpcode(
@@ -98,9 +96,8 @@ Status SoftwareBreakpoint::CreateSoftwareBreakpoint(
     log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64 " -- SUCCESS",
                 __FUNCTION__, addr);
 
-  // Set the breakpoint and verified it was written properly.  Now
-  // create a breakpoint remover that understands how to undo this
-  // breakpoint.
+  // Set the breakpoint and verified it was written properly.  Now create a
+  // breakpoint remover that understands how to undo this breakpoint.
   breakpoint_sp.reset(new SoftwareBreakpoint(process, addr, saved_opcode_bytes,
                                              bp_opcode_bytes, bp_opcode_size));
   return Status();
@@ -280,8 +277,8 @@ Status SoftwareBreakpoint::DoDisable() {
       // Make sure the breakpoint opcode exists at this address
       if (::memcmp(curr_break_op, m_trap_opcodes, m_opcode_size) == 0) {
         break_op_found = true;
-        // We found a valid breakpoint opcode at this address, now restore
-        // the saved opcode.
+        // We found a valid breakpoint opcode at this address, now restore the
+        // saved opcode.
         size_t bytes_written = 0;
         error = m_process.WriteMemory(m_addr, m_saved_opcodes, m_opcode_size,
                                       bytes_written);
diff --git a/source/Host/common/Symbols.cpp b/source/Host/common/Symbols.cpp
index 3f70fdc4bf951..d7e0c13112aaf 100644
--- a/source/Host/common/Symbols.cpp
+++ b/source/Host/common/Symbols.cpp
@@ -8,8 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/Symbols.h"
-#include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
+#include "lldb/Host/FileSystem.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/ArchSpec.h"
@@ -91,7 +91,7 @@ static bool LocateDSYMInVincinityOfExecutable(const ModuleSpec &module_spec,
         ::strncat(path, exec_fspec->GetFilename().AsCString(),
                   sizeof(path) - strlen(path) - 1);
 
-        dsym_fspec.SetFile(path, false);
+        dsym_fspec.SetFile(path, false, FileSpec::Style::native);
 
         ModuleSpecList module_specs;
         ModuleSpec matched_module_spec;
@@ -111,15 +111,15 @@ static bool LocateDSYMInVincinityOfExecutable(const ModuleSpec &module_spec,
 
           // Add a ".dSYM" name to each directory component of the path,
           // stripping off components.  e.g. we may have a binary like
-          // /S/L/F/Foundation.framework/Versions/A/Foundation
-          // and
+          // /S/L/F/Foundation.framework/Versions/A/Foundation and
           // /S/L/F/Foundation.framework.dSYM
           //
-          // so we'll need to start with /S/L/F/Foundation.framework/Versions/A,
-          // add the .dSYM part to the "A", and if that doesn't exist, strip off
-          // the "A" and try it again with "Versions", etc., until we find a
-          // dSYM bundle or we've stripped off enough path components that
-          // there's no need to continue.
+          // so we'll need to start with
+          // /S/L/F/Foundation.framework/Versions/A, add the .dSYM part to the
+          // "A", and if that doesn't exist, strip off the "A" and try it again
+          // with "Versions", etc., until we find a dSYM bundle or we've
+          // stripped off enough path components that there's no need to
+          // continue.
 
           for (int i = 0; i < 4; i++) {
             // Does this part of the path have a "." character - could it be a
@@ -131,7 +131,8 @@ static bool LocateDSYMInVincinityOfExecutable(const ModuleSpec &module_spec,
               dsym_fspec = parent_dirs;
               dsym_fspec.RemoveLastPathComponent();
 
-              // If the current directory name is "Foundation.framework", see if
+              // If the current directory name is "Foundation.framework", see
+              // if
               // "Foundation.framework.dSYM/Contents/Resources/DWARF/Foundation"
               // exists & has the right uuid.
               std::string dsym_fn = fn;
@@ -222,14 +223,18 @@ FileSpec Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec) {
         Target::GetDefaultDebugFileSearchPaths());
 
     // Add module directory.
-    const ConstString &file_dir = module_spec.GetFileSpec().GetDirectory();
+    FileSpec module_file_spec = module_spec.GetFileSpec();
+    // We keep the unresolved pathname if it fails.
+    FileSystem::ResolveSymbolicLink(module_file_spec, module_file_spec);
+
+    const ConstString &file_dir = module_file_spec.GetDirectory();
     debug_file_search_paths.AppendIfUnique(
         FileSpec(file_dir.AsCString("."), true));
 
     // Add current working directory.
     debug_file_search_paths.AppendIfUnique(FileSpec(".", true));
 
-#ifndef LLVM_ON_WIN32
+#ifndef _WIN32
 #if defined(__NetBSD__)
     // Add /usr/libdata/debug directory.
     debug_file_search_paths.AppendIfUnique(
@@ -238,7 +243,7 @@ FileSpec Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec) {
     // Add /usr/lib/debug directory.
     debug_file_search_paths.AppendIfUnique(FileSpec("/usr/lib/debug", true));
 #endif
-#endif // LLVM_ON_WIN32
+#endif // _WIN32
 
     std::string uuid_str;
     const UUID &module_uuid = module_spec.GetUUID();
@@ -246,6 +251,8 @@ FileSpec Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec) {
       // Some debug files are stored in the .build-id directory like this:
       //   /usr/lib/debug/.build-id/ff/e7fe727889ad82bb153de2ad065b2189693315.debug
       uuid_str = module_uuid.GetAsString("");
+      std::transform(uuid_str.begin(), uuid_str.end(), uuid_str.begin(),
+          ::tolower);
       uuid_str.insert(2, 1, '/');
       uuid_str = uuid_str + ".debug";
     }
@@ -275,7 +282,7 @@ FileSpec Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec) {
         FileSpec file_spec(filename, true);
 
         if (llvm::sys::fs::equivalent(file_spec.GetPath(),
-                                      module_spec.GetFileSpec().GetPath()))
+                                      module_file_spec.GetPath()))
           continue;
 
         if (file_spec.Exists()) {
@@ -287,10 +294,9 @@ FileSpec Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec) {
           if (num_specs == 1) {
             ModuleSpec mspec;
             if (specs.GetModuleSpecAtIndex(0, mspec)) {
-              // Skip the uuids check if module_uuid is invalid.
-              // For example, this happens for *.dwp files since
-              // at the moment llvm-dwp doesn't output build ids,
-              // nor does binutils dwp.
+              // Skip the uuids check if module_uuid is invalid. For example,
+              // this happens for *.dwp files since at the moment llvm-dwp
+              // doesn't output build ids, nor does binutils dwp.
               if (!module_uuid.IsValid() || module_uuid == mspec.GetUUID())
                 return file_spec;
             }
diff --git a/source/Host/common/TCPSocket.cpp b/source/Host/common/TCPSocket.cpp
index f896944bb1b36..1a10336f1dfc5 100644
--- a/source/Host/common/TCPSocket.cpp
+++ b/source/Host/common/TCPSocket.cpp
@@ -26,11 +26,11 @@
 #include <sys/socket.h>
 #endif
 
-#if defined(LLVM_ON_WIN32)
+#if defined(_WIN32)
 #include <winsock2.h>
 #endif
 
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 #define CLOSE_SOCKET closesocket
 typedef const char *set_socket_option_arg_type;
 #else
diff --git a/source/Host/common/TaskPool.cpp b/source/Host/common/TaskPool.cpp
index 156a079429985..c54b9a8ae56b1 100644
--- a/source/Host/common/TaskPool.cpp
+++ b/source/Host/common/TaskPool.cpp
@@ -49,8 +49,8 @@ void TaskPool::AddTaskImpl(std::function<void()> &&task_fn) {
 TaskPoolImpl::TaskPoolImpl() : m_thread_count(0) {}
 
 unsigned GetHardwareConcurrencyHint() {
-  // std::thread::hardware_concurrency may return 0
-  // if the value is not well defined or not computable.
+  // std::thread::hardware_concurrency may return 0 if the value is not well
+  // defined or not computable.
   static const unsigned g_hardware_concurrency = 
     std::max(1u, std::thread::hardware_concurrency());
   return g_hardware_concurrency;
@@ -64,9 +64,8 @@ void TaskPoolImpl::AddTask(std::function<void()> &&task_fn) {
   if (m_thread_count < GetHardwareConcurrencyHint()) {
     m_thread_count++;
     // Note that this detach call needs to happen with the m_tasks_mutex held.
-    // This prevents the thread
-    // from exiting prematurely and triggering a linux libc bug
-    // (https://sourceware.org/bugzilla/show_bug.cgi?id=19951).
+    // This prevents the thread from exiting prematurely and triggering a linux
+    // libc bug (https://sourceware.org/bugzilla/show_bug.cgi?id=19951).
     lldb_private::ThreadLauncher::LaunchThread("task-pool.worker", WorkerPtr,
                                                this, nullptr, min_stack_size)
         .Release();
diff --git a/source/Host/common/Terminal.cpp b/source/Host/common/Terminal.cpp
index 022b3fa50a8fe..be912fbe61554 100644
--- a/source/Host/common/Terminal.cpp
+++ b/source/Host/common/Terminal.cpp
@@ -9,6 +9,7 @@
 
 #include "lldb/Host/Terminal.h"
 
+#include "lldb/Host/Config.h"
 #include "lldb/Host/PosixApi.h"
 #include "llvm/ADT/STLExtras.h"
 
@@ -107,9 +108,9 @@ void TerminalState::Clear() {
 }
 
 //----------------------------------------------------------------------
-// Save the current state of the TTY for the file descriptor "fd"
-// and if "save_process_group" is true, attempt to save the process
-// group info for the TTY.
+// Save the current state of the TTY for the file descriptor "fd" and if
+// "save_process_group" is true, attempt to save the process group info for the
+// TTY.
 //----------------------------------------------------------------------
 bool TerminalState::Save(int fd, bool save_process_group) {
   m_tty.SetFileDescriptor(fd);
@@ -142,8 +143,8 @@ bool TerminalState::Save(int fd, bool save_process_group) {
 }
 
 //----------------------------------------------------------------------
-// Restore the state of the TTY using the cached values from a
-// previous call to Save().
+// Restore the state of the TTY using the cached values from a previous call to
+// Save().
 //----------------------------------------------------------------------
 bool TerminalState::Restore() const {
 #ifndef LLDB_DISABLE_POSIX
@@ -173,8 +174,8 @@ bool TerminalState::Restore() const {
 }
 
 //----------------------------------------------------------------------
-// Returns true if this object has valid saved TTY state settings
-// that can be used to restore a previous state.
+// Returns true if this object has valid saved TTY state settings that can be
+// used to restore a previous state.
 //----------------------------------------------------------------------
 bool TerminalState::IsValid() const {
   return m_tty.FileDescriptorIsValid() &&
@@ -236,21 +237,20 @@ bool TerminalStateSwitcher::Restore(uint32_t idx) const {
       m_ttystates[idx].IsValid())
     return true;
 
-  // Set the state to match the index passed in and only update the
-  // current state if there are no errors.
+  // Set the state to match the index passed in and only update the current
+  // state if there are no errors.
   if (m_ttystates[idx].Restore()) {
     m_currentState = idx;
     return true;
   }
 
-  // We failed to set the state. The tty state was invalid or not
-  // initialized.
+  // We failed to set the state. The tty state was invalid or not initialized.
   return false;
 }
 
 //------------------------------------------------------------------
-// Save the state at index "idx" for file descriptor "fd" and
-// save the process group if requested.
+// Save the state at index "idx" for file descriptor "fd" and save the process
+// group if requested.
 //
 // Returns true if the restore was successful, false otherwise.
 //------------------------------------------------------------------
diff --git a/source/Host/common/UDPSocket.cpp b/source/Host/common/UDPSocket.cpp
index 21dacbc626eee..96bcc6a150a9e 100644
--- a/source/Host/common/UDPSocket.cpp
+++ b/source/Host/common/UDPSocket.cpp
@@ -69,8 +69,8 @@ Status UDPSocket::Connect(llvm::StringRef name, bool child_processes_inherit,
   if (!DecodeHostAndPort(name, host_str, port_str, port, &error))
     return error;
 
-  // At this point we have setup the receive port, now we need to
-  // setup the UDP send socket
+  // At this point we have setup the receive port, now we need to setup the UDP
+  // send socket
 
   struct addrinfo hints;
   struct addrinfo *service_info_list = nullptr;
diff --git a/source/Host/common/XML.cpp b/source/Host/common/XML.cpp
index c3169bd6e08d1..7468a3d7ac65e 100644
--- a/source/Host/common/XML.cpp
+++ b/source/Host/common/XML.cpp
@@ -151,6 +151,18 @@ llvm::StringRef XMLNode::GetAttributeValue(const char *name,
     return llvm::StringRef();
 }
 
+bool XMLNode::GetAttributeValueAsUnsigned(const char *name, uint64_t &value,
+                                          uint64_t fail_value, int base) const {
+#if defined(LIBXML2_DEFINED)
+  llvm::StringRef str_value = GetAttributeValue(name, "");
+#else
+  llvm::StringRef str_value;
+#endif
+  bool success = false;
+  value = StringConvert::ToUInt64(str_value.data(), fail_value, base, &success);
+  return success;
+}
+
 void XMLNode::ForEachChildNode(NodeCallback const &callback) const {
 #if defined(LIBXML2_DEFINED)
   if (IsValid())
@@ -240,8 +252,8 @@ void XMLNode::ForEachSiblingElementWithName(
       if (node->type != XML_ELEMENT_NODE)
         continue;
 
-      // If name is nullptr, we take all nodes of type "t", else
-      // just the ones whose name matches
+      // If name is nullptr, we take all nodes of type "t", else just the ones
+      // whose name matches
       if (name) {
         if (strcmp((const char *)node->name, name) != 0)
           continue; // Name mismatch, ignore this one
diff --git a/source/Host/freebsd/Host.cpp b/source/Host/freebsd/Host.cpp
index 124a8a760133a..87552bc2a27ed 100644
--- a/source/Host/freebsd/Host.cpp
+++ b/source/Host/freebsd/Host.cpp
@@ -26,12 +26,9 @@
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
-#include "lldb/Core/Module.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
-#include "lldb/Target/Platform.h"
 #include "lldb/Target/Process.h"
-#include "lldb/Utility/CleanUp.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
 #include "lldb/Utility/Endian.h"
@@ -78,9 +75,11 @@ GetFreeBSDProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
   size_t pathname_len = sizeof(pathname);
   mib[2] = KERN_PROC_PATHNAME;
   if (::sysctl(mib, 4, pathname, &pathname_len, NULL, 0) == 0)
-    process_info.GetExecutableFile().SetFile(pathname, false);
+    process_info.GetExecutableFile().SetFile(pathname, false,
+                                             FileSpec::Style::native);
   else
-    process_info.GetExecutableFile().SetFile(cstr, false);
+    process_info.GetExecutableFile().SetFile(cstr, false,
+                                             FileSpec::Style::native);
 
   if (!(match_info_ptr == NULL ||
         NameMatches(process_info.GetExecutableFile().GetFilename().GetCString(),
@@ -195,9 +194,8 @@ uint32_t Host::FindProcesses(const ProcessInstanceInfoMatch &match_info,
       continue;
 
     // Every thread is a process in FreeBSD, but all the threads of a single
-    // process have the same pid. Do not store the process info in the
-    // result list if a process with given identifier is already registered
-    // there.
+    // process have the same pid. Do not store the process info in the result
+    // list if a process with given identifier is already registered there.
     bool already_registered = false;
     for (uint32_t pi = 0;
          !already_registered && (const int)kinfo.ki_numthreads > 1 &&
@@ -243,14 +241,7 @@ bool Host::GetProcessInfo(lldb::pid_t pid, ProcessInstanceInfo &process_info) {
   return false;
 }
 
-size_t Host::GetEnvironment(StringList &env) {
-  char **host_env = environ;
-  char *env_entry;
-  size_t i;
-  for (i = 0; (env_entry = host_env[i]) != NULL; ++i)
-    env.AppendString(env_entry);
-  return i;
-}
+Environment Host::GetEnvironment() { return Environment(environ); }
 
 Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
   return Status("unimplemented");
diff --git a/source/Host/freebsd/HostInfoFreeBSD.cpp b/source/Host/freebsd/HostInfoFreeBSD.cpp
index 9c82fcca75637..18eae3eb76060 100644
--- a/source/Host/freebsd/HostInfoFreeBSD.cpp
+++ b/source/Host/freebsd/HostInfoFreeBSD.cpp
@@ -18,16 +18,17 @@
 
 using namespace lldb_private;
 
-bool HostInfoFreeBSD::GetOSVersion(uint32_t &major, uint32_t &minor,
-                                   uint32_t &update) {
+llvm::VersionTuple HostInfoFreeBSD::GetOSVersion() {
   struct utsname un;
 
   ::memset(&un, 0, sizeof(utsname));
   if (uname(&un) < 0)
-    return false;
+    return llvm::VersionTuple();
 
-  int status = sscanf(un.release, "%u.%u", &major, &minor);
-  return status == 2;
+  unsigned major, minor;
+  if (2 == sscanf(un.release, "%u.%u", &major, &minor))
+    return llvm::VersionTuple(major, minor);
+  return llvm::VersionTuple();
 }
 
 bool HostInfoFreeBSD::GetOSBuildString(std::string &s) {
@@ -68,9 +69,9 @@ FileSpec HostInfoFreeBSD::GetProgramFileSpec() {
     if (sysctl(exe_path_mib, 4, NULL, &exe_path_size, NULL, 0) == 0) {
       char *exe_path = new char[exe_path_size];
       if (sysctl(exe_path_mib, 4, exe_path, &exe_path_size, NULL, 0) == 0)
-        g_program_filespec.SetFile(exe_path, false);
+        g_program_filespec.SetFile(exe_path, false, FileSpec::Style::native);
       delete[] exe_path;
     }
   }
   return g_program_filespec;
-}
\ No newline at end of file
+}
diff --git a/source/Host/linux/Host.cpp b/source/Host/linux/Host.cpp
index f43090eadf812..1a0eb767eb34b 100644
--- a/source/Host/linux/Host.cpp
+++ b/source/Host/linux/Host.cpp
@@ -20,7 +20,9 @@
 
 // C++ Includes
 // Other libraries and framework includes
+#include "llvm/Object/ELF.h"
 #include "llvm/Support/ScopedPrinter.h"
+
 // Project includes
 #include "lldb/Target/Process.h"
 #include "lldb/Utility/Log.h"
@@ -29,12 +31,9 @@
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/linux/Support.h"
-#include "lldb/Utility/DataBufferHeap.h"
+#include "lldb/Utility/DataBufferLLVM.h"
 #include "lldb/Utility/DataExtractor.h"
 
-#include "lldb/Core/ModuleSpec.h"
-#include "lldb/Symbol/ObjectFile.h"
-
 using namespace lldb;
 using namespace lldb_private;
 
@@ -123,28 +122,27 @@ static bool IsDirNumeric(const char *dname) {
   return true;
 }
 
-static bool GetELFProcessCPUType(llvm::StringRef exe_path,
-                                 ProcessInstanceInfo &process_info) {
-  // Clear the architecture.
-  process_info.GetArchitecture().Clear();
+static ArchSpec GetELFProcessCPUType(llvm::StringRef exe_path) {
+  Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
 
-  ModuleSpecList specs;
-  FileSpec filespec(exe_path, false);
-  const size_t num_specs =
-      ObjectFile::GetModuleSpecifications(filespec, 0, 0, specs);
-  // GetModuleSpecifications() could fail if the executable has been deleted or
-  // is locked.
-  // But it shouldn't return more than 1 architecture.
-  assert(num_specs <= 1 && "Linux plugin supports only a single architecture");
-  if (num_specs == 1) {
-    ModuleSpec module_spec;
-    if (specs.GetModuleSpecAtIndex(0, module_spec) &&
-        module_spec.GetArchitecture().IsValid()) {
-      process_info.GetArchitecture() = module_spec.GetArchitecture();
-      return true;
-    }
+  auto buffer_sp = DataBufferLLVM::CreateSliceFromPath(exe_path, 0x20, 0);
+  if (!buffer_sp)
+    return ArchSpec();
+
+  uint8_t exe_class =
+      llvm::object::getElfArchType(
+          {buffer_sp->GetChars(), size_t(buffer_sp->GetByteSize())})
+          .first;
+
+  switch (exe_class) {
+  case llvm::ELF::ELFCLASS32:
+    return HostInfo::GetArchitecture(HostInfo::eArchKind32);
+  case llvm::ELF::ELFCLASS64:
+    return HostInfo::GetArchitecture(HostInfo::eArchKind64);
+  default:
+    LLDB_LOG(log, "Unknown elf class ({0}) in file {1}", exe_class, exe_path);
+    return ArchSpec();
   }
-  return false;
 }
 
 static bool GetProcessAndStatInfo(::pid_t pid,
@@ -173,7 +171,7 @@ static bool GetProcessAndStatInfo(::pid_t pid,
   llvm::StringRef PathRef = ExePath;
   PathRef.consume_back(" (deleted)");
 
-  GetELFProcessCPUType(PathRef, process_info);
+  process_info.SetArchitecture(GetELFProcessCPUType(PathRef));
 
   // Get the process environment.
   auto BufferOrError = getProcFile(pid, "environ");
@@ -192,14 +190,14 @@ static bool GetProcessAndStatInfo(::pid_t pid,
     return false;
 
   process_info.SetProcessID(pid);
-  process_info.GetExecutableFile().SetFile(PathRef, false);
-  process_info.GetArchitecture().MergeFrom(HostInfo::GetArchitecture());
+  process_info.GetExecutableFile().SetFile(PathRef, false,
+                                           FileSpec::Style::native);
 
   llvm::StringRef Rest = Environ->getBuffer();
   while (!Rest.empty()) {
     llvm::StringRef Var;
     std::tie(Var, Rest) = Rest.split('\0');
-    process_info.GetEnvironmentEntries().AppendArgument(Var);
+    process_info.GetEnvironment().insert(Var);
   }
 
   llvm::StringRef Arg0;
@@ -249,8 +247,8 @@ uint32_t Host::FindProcesses(const ProcessInstanceInfoMatch &match_info,
       if (State == ProcessState::Zombie)
         continue;
 
-      // Check for user match if we're not matching all users and not running as
-      // root.
+      // Check for user match if we're not matching all users and not running
+      // as root.
       if (!all_users && (our_uid != 0) && (process_info.GetUserID() != our_uid))
         continue;
 
@@ -297,14 +295,7 @@ bool Host::GetProcessInfo(lldb::pid_t pid, ProcessInstanceInfo &process_info) {
   return GetProcessAndStatInfo(pid, process_info, State, tracerpid);
 }
 
-size_t Host::GetEnvironment(StringList &env) {
-  char **host_env = environ;
-  char *env_entry;
-  size_t i;
-  for (i = 0; (env_entry = host_env[i]) != NULL; ++i)
-    env.AppendString(env_entry);
-  return i;
-}
+Environment Host::GetEnvironment() { return Environment(environ); }
 
 Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
   return Status("unimplemented");
diff --git a/source/Host/linux/HostInfoLinux.cpp b/source/Host/linux/HostInfoLinux.cpp
index 8d59cda249e83..1d95010e2f736 100644
--- a/source/Host/linux/HostInfoLinux.cpp
+++ b/source/Host/linux/HostInfoLinux.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "lldb/Host/Config.h"
 #include "lldb/Host/linux/HostInfoLinux.h"
 #include "lldb/Utility/Log.h"
 
@@ -25,12 +26,8 @@ using namespace lldb_private;
 
 namespace {
 struct HostInfoLinuxFields {
-  HostInfoLinuxFields() : m_os_major(0), m_os_minor(0), m_os_update(0) {}
-
   std::string m_distribution_id;
-  uint32_t m_os_major;
-  uint32_t m_os_minor;
-  uint32_t m_os_update;
+  llvm::VersionTuple m_os_version;
 };
 
 HostInfoLinuxFields *g_fields = nullptr;
@@ -42,35 +39,21 @@ void HostInfoLinux::Initialize() {
   g_fields = new HostInfoLinuxFields();
 }
 
-bool HostInfoLinux::GetOSVersion(uint32_t &major, uint32_t &minor,
-                                 uint32_t &update) {
-  static bool success = false;
+llvm::VersionTuple HostInfoLinux::GetOSVersion() {
   static llvm::once_flag g_once_flag;
   llvm::call_once(g_once_flag, []() {
-
     struct utsname un;
-    if (uname(&un) == 0) {
-      int status = sscanf(un.release, "%u.%u.%u", &g_fields->m_os_major,
-                          &g_fields->m_os_minor, &g_fields->m_os_update);
-      if (status == 3)
-        success = true;
-      else {
-        // Some kernels omit the update version, so try looking for just "X.Y"
-        // and
-        // set update to 0.
-        g_fields->m_os_update = 0;
-        status = sscanf(un.release, "%u.%u", &g_fields->m_os_major,
-                        &g_fields->m_os_minor);
-        if (status == 2)
-          success = true;
-      }
-    }
+    if (uname(&un) != 0)
+      return;
+
+    llvm::StringRef release = un.release;
+    // The kernel release string can include a lot of stuff (e.g.
+    // 4.9.0-6-amd64). We're only interested in the numbered prefix.
+    release = release.substr(0, release.find_first_not_of("0123456789."));
+    g_fields->m_os_version.tryParse(release);
   });
 
-  major = g_fields->m_os_major;
-  minor = g_fields->m_os_minor;
-  update = g_fields->m_os_update;
-  return success;
+  return g_fields->m_os_version;
 }
 
 bool HostInfoLinux::GetOSBuildString(std::string &s) {
@@ -99,8 +82,8 @@ bool HostInfoLinux::GetOSKernelDescription(std::string &s) {
 }
 
 llvm::StringRef HostInfoLinux::GetDistributionId() {
-  // Try to run 'lbs_release -i', and use that response
-  // for the distribution id.
+  // Try to run 'lbs_release -i', and use that response for the distribution
+  // id.
   static llvm::once_flag g_once_flag;
   llvm::call_once(g_once_flag, []() {
 
@@ -108,8 +91,7 @@ llvm::StringRef HostInfoLinux::GetDistributionId() {
     if (log)
       log->Printf("attempting to determine Linux distribution...");
 
-    // check if the lsb_release command exists at one of the
-    // following paths
+    // check if the lsb_release command exists at one of the following paths
     const char *const exe_paths[] = {"/bin/lsb_release",
                                      "/usr/bin/lsb_release"};
 
@@ -188,7 +170,7 @@ FileSpec HostInfoLinux::GetProgramFileSpec() {
     ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1);
     if (len > 0) {
       exe_path[len] = 0;
-      g_program_filespec.SetFile(exe_path, false);
+      g_program_filespec.SetFile(exe_path, false, FileSpec::Style::native);
     }
   }
 
@@ -204,15 +186,15 @@ bool HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec) {
 }
 
 bool HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
-  FileSpec temp_file("/usr/lib/lldb/plugins", true);
+  FileSpec temp_file("/usr/lib" LLDB_LIBDIR_SUFFIX "/lldb/plugins", true);
   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
   return true;
 }
 
 bool HostInfoLinux::ComputeUserPluginsDirectory(FileSpec &file_spec) {
   // XDG Base Directory Specification
-  // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
-  // If XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
+  // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html If
+  // XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
   const char *xdg_data_home = getenv("XDG_DATA_HOME");
   if (xdg_data_home && xdg_data_home[0]) {
     std::string user_plugin_dir(xdg_data_home);
diff --git a/source/Host/macosx/Symbols.cpp b/source/Host/macosx/Symbols.cpp
index 98c110b1bed67..b01c48e51d900 100644
--- a/source/Host/macosx/Symbols.cpp
+++ b/source/Host/macosx/Symbols.cpp
@@ -23,7 +23,7 @@
 #include "Host/macosx/cfcpp/CFCData.h"
 #include "Host/macosx/cfcpp/CFCReleaser.h"
 #include "Host/macosx/cfcpp/CFCString.h"
-#include "lldb/Core/Module.h"
+#include "lldb/Core/ModuleList.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Symbol/ObjectFile.h"
@@ -55,6 +55,13 @@ CFDictionaryRef DBGCopyDSYMPropertyLists(CFURLRef dsym_url);
 
 int LocateMacOSXFilesUsingDebugSymbols(const ModuleSpec &module_spec,
                                        ModuleSpec &return_module_spec) {
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+  if (!ModuleList::GetGlobalModuleListProperties().GetEnableExternalLookup()) {
+    if (log)
+      log->Printf("Spotlight lookup for .dSYM bundles is disabled.");
+    return 0;
+  }
+  
   return_module_spec = module_spec;
   return_module_spec.GetFileSpec().Clear();
   return_module_spec.GetSymbolFileSpec().Clear();
@@ -69,8 +76,8 @@ int LocateMacOSXFilesUsingDebugSymbols(const ModuleSpec &module_spec,
 
   if (uuid && uuid->IsValid()) {
     // Try and locate the dSYM file using DebugSymbols first
-    const UInt8 *module_uuid = (const UInt8 *)uuid->GetBytes();
-    if (module_uuid != NULL) {
+    llvm::ArrayRef<uint8_t> module_uuid = uuid->GetBytes();
+    if (module_uuid.size() == 16) {
       CFCReleaser<CFUUIDRef> module_uuid_ref(::CFUUIDCreateWithBytes(
           NULL, module_uuid[0], module_uuid[1], module_uuid[2], module_uuid[3],
           module_uuid[4], module_uuid[5], module_uuid[6], module_uuid[7],
@@ -80,7 +87,6 @@ int LocateMacOSXFilesUsingDebugSymbols(const ModuleSpec &module_spec,
       if (module_uuid_ref.get()) {
         CFCReleaser<CFURLRef> exec_url;
         const FileSpec *exec_fspec = module_spec.GetFileSpecPtr();
-        Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
         if (exec_fspec) {
           char exec_cf_path[PATH_MAX];
           if (exec_fspec->GetPath(exec_cf_path, sizeof(exec_cf_path)))
@@ -241,52 +247,53 @@ FileSpec Symbols::FindSymbolFileInBundle(const FileSpec &dsym_bundle_fspec,
                                          const lldb_private::UUID *uuid,
                                          const ArchSpec *arch) {
   char path[PATH_MAX];
+  if (dsym_bundle_fspec.GetPath(path, sizeof(path)) == 0)
+    return {};
 
-  FileSpec dsym_fspec;
+  ::strncat(path, "/Contents/Resources/DWARF", sizeof(path) - strlen(path) - 1);
 
-  if (dsym_bundle_fspec.GetPath(path, sizeof(path))) {
-    ::strncat(path, "/Contents/Resources/DWARF",
-              sizeof(path) - strlen(path) - 1);
+  DIR *dirp = opendir(path);
+  if (!dirp)
+    return {};
 
-    lldb_utility::CleanUp<DIR *, int> dirp(opendir(path), NULL, closedir);
-    if (dirp.is_valid()) {
-      dsym_fspec.GetDirectory().SetCString(path);
-      struct dirent *dp;
-      while ((dp = readdir(dirp.get())) != NULL) {
-        // Only search directories
-        if (dp->d_type == DT_DIR || dp->d_type == DT_UNKNOWN) {
-          if (dp->d_namlen == 1 && dp->d_name[0] == '.')
-            continue;
+  // Make sure we close the directory before exiting this scope.
+  CleanUp cleanup_dir(closedir, dirp);
 
-          if (dp->d_namlen == 2 && dp->d_name[0] == '.' && dp->d_name[1] == '.')
-            continue;
-        }
+  FileSpec dsym_fspec;
+  dsym_fspec.GetDirectory().SetCString(path);
+  struct dirent *dp;
+  while ((dp = readdir(dirp)) != NULL) {
+    // Only search directories
+    if (dp->d_type == DT_DIR || dp->d_type == DT_UNKNOWN) {
+      if (dp->d_namlen == 1 && dp->d_name[0] == '.')
+        continue;
 
-        if (dp->d_type == DT_REG || dp->d_type == DT_UNKNOWN) {
-          dsym_fspec.GetFilename().SetCString(dp->d_name);
-          ModuleSpecList module_specs;
-          if (ObjectFile::GetModuleSpecifications(dsym_fspec, 0, 0,
-                                                  module_specs)) {
-            ModuleSpec spec;
-            for (size_t i = 0; i < module_specs.GetSize(); ++i) {
-              bool got_spec = module_specs.GetModuleSpecAtIndex(i, spec);
-              UNUSED_IF_ASSERT_DISABLED(got_spec);
-              assert(got_spec);
-              if ((uuid == NULL ||
-                   (spec.GetUUIDPtr() && spec.GetUUID() == *uuid)) &&
-                  (arch == NULL ||
-                   (spec.GetArchitecturePtr() &&
-                    spec.GetArchitecture().IsCompatibleMatch(*arch)))) {
-                return dsym_fspec;
-              }
-            }
+      if (dp->d_namlen == 2 && dp->d_name[0] == '.' && dp->d_name[1] == '.')
+        continue;
+    }
+
+    if (dp->d_type == DT_REG || dp->d_type == DT_UNKNOWN) {
+      dsym_fspec.GetFilename().SetCString(dp->d_name);
+      ModuleSpecList module_specs;
+      if (ObjectFile::GetModuleSpecifications(dsym_fspec, 0, 0, module_specs)) {
+        ModuleSpec spec;
+        for (size_t i = 0; i < module_specs.GetSize(); ++i) {
+          bool got_spec = module_specs.GetModuleSpecAtIndex(i, spec);
+          UNUSED_IF_ASSERT_DISABLED(got_spec);
+          assert(got_spec);
+          if ((uuid == NULL ||
+               (spec.GetUUIDPtr() && spec.GetUUID() == *uuid)) &&
+              (arch == NULL ||
+               (spec.GetArchitecturePtr() &&
+                spec.GetArchitecture().IsCompatibleMatch(*arch)))) {
+            return dsym_fspec;
           }
         }
       }
     }
   }
-  dsym_fspec.Clear();
-  return dsym_fspec;
+
+  return {};
 }
 
 static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
@@ -302,7 +309,8 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
         (CFDictionaryRef)uuid_dict, CFSTR("DBGSymbolRichExecutable"));
     if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
       if (CFCString::FileSystemRepresentation(cf_str, str)) {
-        module_spec.GetFileSpec().SetFile(str.c_str(), true);
+        module_spec.GetFileSpec().SetFile(str.c_str(), true,
+                                          FileSpec::Style::native);
         if (log) {
           log->Printf(
               "From dsymForUUID plist: Symbol rich executable is at '%s'",
@@ -315,7 +323,8 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
                                                CFSTR("DBGDSYMPath"));
     if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
       if (CFCString::FileSystemRepresentation(cf_str, str)) {
-        module_spec.GetSymbolFileSpec().SetFile(str.c_str(), true);
+        module_spec.GetSymbolFileSpec().SetFile(str.c_str(), true,
+                                                FileSpec::Style::native);
         success = true;
         if (log) {
           log->Printf("From dsymForUUID plist: dSYM is at '%s'", str.c_str());
@@ -333,28 +342,13 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
     std::string DBGBuildSourcePath;
     std::string DBGSourcePath;
 
-    cf_str = (CFStringRef)CFDictionaryGetValue((CFDictionaryRef)uuid_dict,
-                                               CFSTR("DBGBuildSourcePath"));
-    if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
-      CFCString::FileSystemRepresentation(cf_str, DBGBuildSourcePath);
-    }
-
-    cf_str = (CFStringRef)CFDictionaryGetValue((CFDictionaryRef)uuid_dict,
-                                               CFSTR("DBGSourcePath"));
-    if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
-      CFCString::FileSystemRepresentation(cf_str, DBGSourcePath);
-    }
-
-    if (!DBGBuildSourcePath.empty() && !DBGSourcePath.empty()) {
-      if (DBGSourcePath[0] == '~') {
-        FileSpec resolved_source_path(DBGSourcePath.c_str(), true);
-        DBGSourcePath = resolved_source_path.GetPath();
-      }
-      module_spec.GetSourceMappingList().Append(
-          ConstString(DBGBuildSourcePath.c_str()),
-          ConstString(DBGSourcePath.c_str()), true);
-    }
-
+    // If DBGVersion 1 or DBGVersion missing, ignore DBGSourcePathRemapping.
+    // If DBGVersion 2, strip last two components of path remappings from
+    //                  entries to fix an issue with a specific set of
+    //                  DBGSourcePathRemapping entries that lldb worked
+    //                  with.
+    // If DBGVersion 3, trust & use the source path remappings as-is.
+    //
     cf_dict = (CFDictionaryRef)CFDictionaryGetValue(
         (CFDictionaryRef)uuid_dict, CFSTR("DBGSourcePathRemapping"));
     if (cf_dict && CFGetTypeID(cf_dict) == CFDictionaryGetTypeID()) {
@@ -401,10 +395,9 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
           }
           if (!DBGBuildSourcePath.empty() && !DBGSourcePath.empty()) {
             // In the "old style" DBGSourcePathRemapping dictionary, the
-            // DBGSourcePath values
-            // (the "values" half of key-value path pairs) were wrong.  Ignore
-            // them and use the
-            // universal DBGSourcePath string from earlier.
+            // DBGSourcePath values (the "values" half of key-value path pairs)
+            // were wrong.  Ignore them and use the universal DBGSourcePath
+            // string from earlier.
             if (new_style_source_remapping_dictionary == true &&
                 !original_DBGSourcePath_value.empty()) {
               DBGSourcePath = original_DBGSourcePath_value;
@@ -414,9 +407,9 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
               DBGSourcePath = resolved_source_path.GetPath();
             }
             // With version 2 of DBGSourcePathRemapping, we can chop off the
-            // last two filename parts from the source remapping and get a
-            // more general source remapping that still works. Add this as
-            // another option in addition to the full source path remap.
+            // last two filename parts from the source remapping and get a more
+            // general source remapping that still works. Add this as another
+            // option in addition to the full source path remap.
             module_spec.GetSourceMappingList().Append(
                 ConstString(DBGBuildSourcePath.c_str()),
                 ConstString(DBGSourcePath.c_str()), true);
@@ -439,6 +432,32 @@ static bool GetModuleSpecInfoFromUUIDDictionary(CFDictionaryRef uuid_dict,
           free(values);
       }
     }
+
+
+    // If we have a DBGBuildSourcePath + DBGSourcePath pair, append them to the
+    // source remappings list.
+
+    cf_str = (CFStringRef)CFDictionaryGetValue((CFDictionaryRef)uuid_dict,
+                                               CFSTR("DBGBuildSourcePath"));
+    if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
+      CFCString::FileSystemRepresentation(cf_str, DBGBuildSourcePath);
+    }
+
+    cf_str = (CFStringRef)CFDictionaryGetValue((CFDictionaryRef)uuid_dict,
+                                               CFSTR("DBGSourcePath"));
+    if (cf_str && CFGetTypeID(cf_str) == CFStringGetTypeID()) {
+      CFCString::FileSystemRepresentation(cf_str, DBGSourcePath);
+    }
+
+    if (!DBGBuildSourcePath.empty() && !DBGSourcePath.empty()) {
+      if (DBGSourcePath[0] == '~') {
+        FileSpec resolved_source_path(DBGSourcePath.c_str(), true);
+        DBGSourcePath = resolved_source_path.GetPath();
+      }
+      module_spec.GetSourceMappingList().Append(
+          ConstString(DBGBuildSourcePath.c_str()),
+          ConstString(DBGSourcePath.c_str()), true);
+    }
   }
   return success;
 }
@@ -450,8 +469,7 @@ bool Symbols::DownloadObjectAndSymbolFile(ModuleSpec &module_spec,
   const FileSpec *file_spec_ptr = module_spec.GetFileSpecPtr();
 
   // It's expensive to check for the DBGShellCommands defaults setting, only do
-  // it once per
-  // lldb run and cache the result.
+  // it once per lldb run and cache the result.
   static bool g_have_checked_for_dbgshell_command = false;
   static const char *g_dbgshell_command = NULL;
   if (g_have_checked_for_dbgshell_command == false) {
@@ -473,8 +491,7 @@ bool Symbols::DownloadObjectAndSymbolFile(ModuleSpec &module_spec,
   }
 
   // When g_dbgshell_command is NULL, the user has not enabled the use of an
-  // external program
-  // to find the symbols, don't run it for them.
+  // external program to find the symbols, don't run it for them.
   if (force_lookup == false && g_dbgshell_command == NULL) {
     return false;
   }
@@ -489,12 +506,14 @@ bool Symbols::DownloadObjectAndSymbolFile(ModuleSpec &module_spec,
           getenv("LLDB_APPLE_DSYMFORUUID_EXECUTABLE");
       FileSpec dsym_for_uuid_exe_spec;
       if (dsym_for_uuid_exe_path_cstr) {
-        dsym_for_uuid_exe_spec.SetFile(dsym_for_uuid_exe_path_cstr, true);
+        dsym_for_uuid_exe_spec.SetFile(dsym_for_uuid_exe_path_cstr, true,
+                                       FileSpec::Style::native);
         g_dsym_for_uuid_exe_exists = dsym_for_uuid_exe_spec.Exists();
       }
 
       if (!g_dsym_for_uuid_exe_exists) {
-        dsym_for_uuid_exe_spec.SetFile("/usr/local/bin/dsymForUUID", false);
+        dsym_for_uuid_exe_spec.SetFile("/usr/local/bin/dsymForUUID", false,
+                                       FileSpec::Style::native);
         g_dsym_for_uuid_exe_exists = dsym_for_uuid_exe_spec.Exists();
         if (!g_dsym_for_uuid_exe_exists) {
           long bufsize;
@@ -508,14 +527,16 @@ bool Symbols::DownloadObjectAndSymbolFile(ModuleSpec &module_spec,
                 tilde_rc && tilde_rc->pw_dir) {
               std::string dsymforuuid_path(tilde_rc->pw_dir);
               dsymforuuid_path += "/bin/dsymForUUID";
-              dsym_for_uuid_exe_spec.SetFile(dsymforuuid_path.c_str(), false);
+              dsym_for_uuid_exe_spec.SetFile(dsymforuuid_path.c_str(), false,
+                                             FileSpec::Style::native);
               g_dsym_for_uuid_exe_exists = dsym_for_uuid_exe_spec.Exists();
             }
           }
         }
       }
       if (!g_dsym_for_uuid_exe_exists && g_dbgshell_command != NULL) {
-        dsym_for_uuid_exe_spec.SetFile(g_dbgshell_command, true);
+        dsym_for_uuid_exe_spec.SetFile(g_dbgshell_command, true,
+                                       FileSpec::Style::native);
         g_dsym_for_uuid_exe_exists = dsym_for_uuid_exe_spec.Exists();
       }
 
@@ -561,8 +582,9 @@ bool Symbols::DownloadObjectAndSymbolFile(ModuleSpec &module_spec,
             &exit_status,    // Exit status
             &signo,          // Signal int *
             &command_output, // Command output
-            30,     // Large timeout to allow for long dsym download times
-            false); // Don't run in a shell (we don't need shell expansion)
+            std::chrono::seconds(
+                30), // Large timeout to allow for long dsym download times
+            false);  // Don't run in a shell (we don't need shell expansion)
         if (error.Success() && exit_status == 0 && !command_output.empty()) {
           CFCData data(CFDataCreateWithBytesNoCopy(
               NULL, (const UInt8 *)command_output.data(), command_output.size(),
diff --git a/source/Host/macosx/cfcpp/CFCMutableDictionary.cpp b/source/Host/macosx/cfcpp/CFCMutableDictionary.cpp
index 201ec9a8f5c24..0c52aa3ed0517 100644
--- a/source/Host/macosx/cfcpp/CFCMutableDictionary.cpp
+++ b/source/Host/macosx/cfcpp/CFCMutableDictionary.cpp
@@ -352,9 +352,8 @@ bool CFCMutableDictionary::AddValueUInt64(CFStringRef key, uint64_t value,
   CFMutableDictionaryRef dict = Dictionary(can_create);
   if (dict != NULL) {
     // The number may appear negative if the MSBit is set in "value". Due to a
-    // limitation of
-    // CFNumber, there isn't a way to have it show up otherwise as of this
-    // writing.
+    // limitation of CFNumber, there isn't a way to have it show up otherwise
+    // as of this writing.
     CFCReleaser<CFNumberRef> cf_number(
         ::CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt64Type, &value));
     if (cf_number.get()) {
@@ -371,9 +370,8 @@ bool CFCMutableDictionary::SetValueUInt64(CFStringRef key, uint64_t value,
   CFMutableDictionaryRef dict = Dictionary(can_create);
   if (dict != NULL) {
     // The number may appear negative if the MSBit is set in "value". Due to a
-    // limitation of
-    // CFNumber, there isn't a way to have it show up otherwise as of this
-    // writing.
+    // limitation of CFNumber, there isn't a way to have it show up otherwise
+    // as of this writing.
     CFCReleaser<CFNumberRef> cf_number(
         ::CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt64Type, &value));
     if (cf_number.get()) {
@@ -390,9 +388,8 @@ bool CFCMutableDictionary::AddValueDouble(CFStringRef key, double value,
   CFMutableDictionaryRef dict = Dictionary(can_create);
   if (dict != NULL) {
     // The number may appear negative if the MSBit is set in "value". Due to a
-    // limitation of
-    // CFNumber, there isn't a way to have it show up otherwise as of this
-    // writing.
+    // limitation of CFNumber, there isn't a way to have it show up otherwise
+    // as of this writing.
     CFCReleaser<CFNumberRef> cf_number(
         ::CFNumberCreate(kCFAllocatorDefault, kCFNumberDoubleType, &value));
     if (cf_number.get()) {
@@ -409,9 +406,8 @@ bool CFCMutableDictionary::SetValueDouble(CFStringRef key, double value,
   CFMutableDictionaryRef dict = Dictionary(can_create);
   if (dict != NULL) {
     // The number may appear negative if the MSBit is set in "value". Due to a
-    // limitation of
-    // CFNumber, there isn't a way to have it show up otherwise as of this
-    // writing.
+    // limitation of CFNumber, there isn't a way to have it show up otherwise
+    // as of this writing.
     CFCReleaser<CFNumberRef> cf_number(
         ::CFNumberCreate(kCFAllocatorDefault, kCFNumberDoubleType, &value));
     if (cf_number.get()) {
diff --git a/source/Host/macosx/cfcpp/CFCString.cpp b/source/Host/macosx/cfcpp/CFCString.cpp
index 0d3853c60a72f..6191f873c98a2 100644
--- a/source/Host/macosx/cfcpp/CFCString.cpp
+++ b/source/Host/macosx/cfcpp/CFCString.cpp
@@ -88,9 +88,8 @@ const char *CFCString::UTF8(std::string &str) {
   return CFCString::UTF8(get(), str);
 }
 
-// Static function that puts a copy of the UTF8 contents of CF_STR into STR
-// and returns the C string pointer that is contained in STR when successful,
-// else
+// Static function that puts a copy of the UTF8 contents of CF_STR into STR and
+// returns the C string pointer that is contained in STR when successful, else
 // NULL is returned. This allows the std::string parameter to own the extracted
 // string,
 // and also allows that string to be returned as a C string pointer that can be
@@ -129,9 +128,9 @@ const char *CFCString::ExpandTildeInPath(const char *path,
 
 // Static function that puts a copy of the file system representation of CF_STR
 // into STR and returns the C string pointer that is contained in STR when
-// successful, else NULL is returned. This allows the std::string parameter
-// to own the extracted string, and also allows that string to be returned as
-// a C string pointer that can be used.
+// successful, else NULL is returned. This allows the std::string parameter to
+// own the extracted string, and also allows that string to be returned as a C
+// string pointer that can be used.
 
 const char *CFCString::FileSystemRepresentation(CFStringRef cf_str,
                                                 std::string &str) {
diff --git a/source/Host/macosx/objcxx/CMakeLists.txt b/source/Host/macosx/objcxx/CMakeLists.txt
new file mode 100644
index 0000000000000..77e3091dc4fed
--- /dev/null
+++ b/source/Host/macosx/objcxx/CMakeLists.txt
@@ -0,0 +1,20 @@
+
+remove_module_flags()
+include_directories(..)
+
+add_lldb_library(lldbHostMacOSXObjCXX
+  Host.mm
+  HostInfoMacOSX.mm
+  HostThreadMacOSX.mm
+
+  LINK_LIBS
+    lldbCore
+    lldbSymbol
+    lldbTarget
+    lldbUtility
+    ${EXTRA_LIBS}
+
+  LINK_COMPONENTS
+    Object
+    Support
+  )
diff --git a/source/Host/macosx/Host.mm b/source/Host/macosx/objcxx/Host.mm
index 7359815fdf704..a70bf0421ec48 100644
--- a/source/Host/macosx/Host.mm
+++ b/source/Host/macosx/objcxx/Host.mm
@@ -54,13 +54,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include "lldb/Core/Communication.h"
-#include "lldb/Core/Module.h"
-#include "lldb/Core/ModuleSpec.h"
 #include "lldb/Host/ConnectionFileDescriptor.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/ThreadLauncher.h"
-#include "lldb/Target/Platform.h"
+#include "lldb/Target/ProcessLaunchInfo.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Utility/ArchSpec.h"
 #include "lldb/Utility/CleanUp.h"
@@ -72,15 +69,16 @@
 #include "lldb/Utility/NameMatches.h"
 #include "lldb/Utility/StreamString.h"
 #include "lldb/Utility/StructuredData.h"
+#include "lldb/lldb-defines.h"
 
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Errno.h"
 
-#include "cfcpp/CFCBundle.h"
-#include "cfcpp/CFCMutableArray.h"
-#include "cfcpp/CFCMutableDictionary.h"
-#include "cfcpp/CFCReleaser.h"
-#include "cfcpp/CFCString.h"
+#include "../cfcpp/CFCBundle.h"
+#include "../cfcpp/CFCMutableArray.h"
+#include "../cfcpp/CFCMutableDictionary.h"
+#include "../cfcpp/CFCReleaser.h"
+#include "../cfcpp/CFCString.h"
 
 #include <objc/objc-auto.h>
 
@@ -107,7 +105,7 @@ bool Host::GetBundleDirectory(const FileSpec &file,
     if (file.GetPath(path, sizeof(path))) {
       CFCBundle bundle(path);
       if (bundle.GetPath(path, sizeof(path))) {
-        bundle_directory.SetFile(path, false);
+        bundle_directory.SetFile(path, false, FileSpec::Style::native);
         return true;
       }
     }
@@ -127,7 +125,7 @@ bool Host::ResolveExecutableInBundle(FileSpec &file) {
       if (url.get()) {
         if (::CFURLGetFileSystemRepresentation(url.get(), YES, (UInt8 *)path,
                                                sizeof(path))) {
-          file.SetFile(path, false);
+          file.SetFile(path, false, FileSpec::Style::native);
           return true;
         }
       }
@@ -184,175 +182,6 @@ static bool WaitForProcessToSIGSTOP(const lldb::pid_t pid,
 }
 #if !defined(__arm__) && !defined(__arm64__) && !defined(__aarch64__)
 
-// static lldb::pid_t
-// LaunchInNewTerminalWithCommandFile
-//(
-//    const char **argv,
-//    const char **envp,
-//    const char *working_dir,
-//    const ArchSpec *arch_spec,
-//    bool stop_at_entry,
-//    bool disable_aslr
-//)
-//{
-//    if (!argv || !argv[0])
-//        return LLDB_INVALID_PROCESS_ID;
-//
-//    OSStatus error = 0;
-//
-//    FileSpec program (argv[0], false);
-//
-//
-//    std::string unix_socket_name;
-//
-//    char temp_file_path[PATH_MAX];
-//    const char *tmpdir = ::getenv ("TMPDIR");
-//    if (tmpdir == NULL)
-//        tmpdir = "/tmp/";
-//    ::snprintf (temp_file_path, sizeof(temp_file_path), "%s%s-XXXXXX", tmpdir,
-//    program.GetFilename().AsCString());
-//
-//    if (::mktemp (temp_file_path) == NULL)
-//        return LLDB_INVALID_PROCESS_ID;
-//
-//    unix_socket_name.assign (temp_file_path);
-//
-//    ::strlcat (temp_file_path, ".command", sizeof (temp_file_path));
-//
-//    StreamFile command_file;
-//    command_file.GetFile().Open (temp_file_path,
-//                                 File::eOpenOptionWrite |
-//                                 File::eOpenOptionCanCreate,
-//                                 lldb::eFilePermissionsDefault);
-//
-//    if (!command_file.GetFile().IsValid())
-//        return LLDB_INVALID_PROCESS_ID;
-//
-//    FileSpec darwin_debug_file_spec;
-//    if (!HostInfo::GetLLDBPath (ePathTypeSupportExecutableDir,
-//    darwin_debug_file_spec))
-//        return LLDB_INVALID_PROCESS_ID;
-//    darwin_debug_file_spec.GetFilename().SetCString("darwin-debug");
-//
-//    if (!darwin_debug_file_spec.Exists())
-//        return LLDB_INVALID_PROCESS_ID;
-//
-//    char launcher_path[PATH_MAX];
-//    darwin_debug_file_spec.GetPath(launcher_path, sizeof(launcher_path));
-//    command_file.Printf("\"%s\" ", launcher_path);
-//
-//    command_file.Printf("--unix-socket=%s ", unix_socket_name.c_str());
-//
-//    if (arch_spec && arch_spec->IsValid())
-//    {
-//        command_file.Printf("--arch=%s ", arch_spec->GetArchitectureName());
-//    }
-//
-//    if (disable_aslr)
-//    {
-//        command_file.PutCString("--disable-aslr ");
-//    }
-//
-//    command_file.PutCString("-- ");
-//
-//    if (argv)
-//    {
-//        for (size_t i=0; argv[i] != NULL; ++i)
-//        {
-//            command_file.Printf("\"%s\" ", argv[i]);
-//        }
-//    }
-//    command_file.PutCString("\necho Process exited with status $?\n");
-//    command_file.GetFile().Close();
-//    if (::chmod (temp_file_path, S_IRWXU | S_IRWXG) != 0)
-//        return LLDB_INVALID_PROCESS_ID;
-//
-//    CFCMutableDictionary cf_env_dict;
-//
-//    const bool can_create = true;
-//    if (envp)
-//    {
-//        for (size_t i=0; envp[i] != NULL; ++i)
-//        {
-//            const char *env_entry = envp[i];
-//            const char *equal_pos = strchr(env_entry, '=');
-//            if (equal_pos)
-//            {
-//                std::string env_key (env_entry, equal_pos);
-//                std::string env_val (equal_pos + 1);
-//                CFCString cf_env_key (env_key.c_str(), kCFStringEncodingUTF8);
-//                CFCString cf_env_val (env_val.c_str(), kCFStringEncodingUTF8);
-//                cf_env_dict.AddValue (cf_env_key.get(), cf_env_val.get(),
-//                can_create);
-//            }
-//        }
-//    }
-//
-//    LSApplicationParameters app_params;
-//    ::memset (&app_params, 0, sizeof (app_params));
-//    app_params.flags = kLSLaunchDontAddToRecents | kLSLaunchAsync;
-//    app_params.argv = NULL;
-//    app_params.environment = (CFDictionaryRef)cf_env_dict.get();
-//
-//    CFCReleaser<CFURLRef> command_file_url
-//    (::CFURLCreateFromFileSystemRepresentation (NULL,
-//                                                                                       (const UInt8 *)temp_file_path,
-//                                                                                       strlen(temp_file_path),
-//                                                                                       false));
-//
-//    CFCMutableArray urls;
-//
-//    // Terminal.app will open the ".command" file we have created
-//    // and run our process inside it which will wait at the entry point
-//    // for us to attach.
-//    urls.AppendValue(command_file_url.get());
-//
-//
-//    lldb::pid_t pid = LLDB_INVALID_PROCESS_ID;
-//
-//    Status lldb_error;
-//    // Sleep and wait a bit for debugserver to start to listen...
-//    char connect_url[128];
-//    ::snprintf (connect_url, sizeof(connect_url), "unix-accept://%s",
-//    unix_socket_name.c_str());
-//
-//    // Spawn a new thread to accept incoming connection on the connect_url
-//    // so we can grab the pid from the inferior
-//    lldb::thread_t accept_thread = Host::ThreadCreate
-//    (unix_socket_name.c_str(),
-//                                                       AcceptPIDFromInferior,
-//                                                       connect_url,
-//                                                       &lldb_error);
-//
-//    ProcessSerialNumber psn;
-//    error = LSOpenURLsWithRole(urls.get(), kLSRolesShell, NULL, &app_params,
-//    &psn, 1);
-//    if (error == noErr)
-//    {
-//        thread_result_t accept_thread_result = NULL;
-//        if (Host::ThreadJoin (accept_thread, &accept_thread_result,
-//        &lldb_error))
-//        {
-//            if (accept_thread_result)
-//            {
-//                pid = (intptr_t)accept_thread_result;
-//
-//                // Wait for process to be stopped the entry point by watching
-//                // for the process status to be set to SSTOP which indicates
-//                it it
-//                // SIGSTOP'ed at the entry point
-//                WaitForProcessToSIGSTOP (pid, 5);
-//            }
-//        }
-//    }
-//    else
-//    {
-//        Host::ThreadCancel (accept_thread, &lldb_error);
-//    }
-//
-//    return pid;
-//}
-
 const char *applscript_in_new_tty = "tell application \"Terminal\"\n"
                                     "   activate\n"
                                     "	do script \"/bin/bash -c '%s';exit\"\n"
@@ -388,9 +217,8 @@ LaunchInNewTerminalWithAppleScript(const char *exe_path,
   }
 
   StreamString command;
-  FileSpec darwin_debug_file_spec;
-  if (!HostInfo::GetLLDBPath(ePathTypeSupportExecutableDir,
-                             darwin_debug_file_spec)) {
+  FileSpec darwin_debug_file_spec = HostInfo::GetSupportExeDir();
+  if (!darwin_debug_file_spec) {
     error.SetErrorString("can't locate the 'darwin-debug' executable");
     return error;
   }
@@ -431,33 +259,16 @@ LaunchInNewTerminalWithAppleScript(const char *exe_path,
     command.PutCString(" --disable-aslr");
 
   // We are launching on this host in a terminal. So compare the environment on
-  // the host
-  // to what is supplied in the launch_info. Any items that aren't in the host
-  // environment
-  // need to be sent to darwin-debug. If we send all environment entries, we
-  // might blow the
-  // max command line length, so we only send user modified entries.
-  const char **envp =
-      launch_info.GetEnvironmentEntries().GetConstArgumentVector();
-
-  StringList host_env;
-  const size_t host_env_count = Host::GetEnvironment(host_env);
+  // the host to what is supplied in the launch_info. Any items that aren't in
+  // the host environment need to be sent to darwin-debug. If we send all
+  // environment entries, we might blow the max command line length, so we only
+  // send user modified entries.
+  Environment host_env = Host::GetEnvironment();
 
-  if (envp && envp[0]) {
-    const char *env_entry;
-    for (size_t env_idx = 0; (env_entry = envp[env_idx]) != NULL; ++env_idx) {
-      bool add_entry = true;
-      for (size_t i = 0; i < host_env_count; ++i) {
-        const char *host_env_entry = host_env.GetStringAtIndex(i);
-        if (strcmp(env_entry, host_env_entry) == 0) {
-          add_entry = false;
-          break;
-        }
-      }
-      if (add_entry) {
-        command.Printf(" --env='%s'", env_entry);
-      }
-    }
+  for (const auto &KV : launch_info.GetEnvironment()) {
+    auto host_entry = host_env.find(KV.first());
+    if (host_entry == host_env.end() || host_entry->second != KV.second)
+      command.Format(" --env='{0}'", Environment::compose(KV));
   }
 
   command.PutCString(" -- ");
@@ -479,19 +290,8 @@ LaunchInNewTerminalWithAppleScript(const char *exe_path,
 
   StreamString applescript_source;
 
-  //    if (tty_name && tty_name[0])
-  //    {
-  //        applescript_source.Printf (applscript_in_existing_tty,
-  //                                   tty_command,
-  //                                   tty_name);
-  //    }
-  //    else
-  //    {
   applescript_source.Printf(applscript_in_new_tty,
                             command.GetString().str().c_str());
-  //    }
-
-  // puts (script_source);
   NSAppleScript *applescript = [[NSAppleScript alloc]
       initWithSource:[NSString stringWithCString:applescript_source.GetString()
                                                      .str()
@@ -641,14 +441,7 @@ bool Host::OpenFileInExternalEditor(const FileSpec &file_spec,
 #endif // #if !defined(__arm__) && !defined(__arm64__) && !defined(__aarch64__)
 }
 
-size_t Host::GetEnvironment(StringList &env) {
-  char **host_env = *_NSGetEnviron();
-  char *env_entry;
-  size_t i;
-  for (i = 0; (env_entry = host_env[i]) != NULL; ++i)
-    env.AppendString(env_entry);
-  return i;
-}
+Environment Host::GetEnvironment() { return Environment(*_NSGetEnviron()); }
 
 static bool GetMacOSXProcessCPUType(ProcessInstanceInfo &process_info) {
   if (process_info.ProcessIDIsValid()) {
@@ -748,7 +541,8 @@ static bool GetMacOSXProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
            triple_arch == llvm::Triple::x86_64);
       const char *cstr = data.GetCStr(&offset);
       if (cstr) {
-        process_info.GetExecutableFile().SetFile(cstr, false);
+        process_info.GetExecutableFile().SetFile(cstr, false,
+                                                 FileSpec::Style::native);
 
         if (match_info_ptr == NULL ||
             NameMatches(
@@ -770,7 +564,7 @@ static bool GetMacOSXProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
               proc_args.AppendArgument(llvm::StringRef(cstr));
           }
 
-          Args &proc_env = process_info.GetEnvironmentEntries();
+          Environment &proc_env = process_info.GetEnvironment();
           while ((cstr = data.GetCStr(&offset))) {
             if (cstr[0] == '\0')
               break;
@@ -785,7 +579,7 @@ static bool GetMacOSXProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
                     llvm::Triple::MacOSX);
             }
 
-            proc_env.AppendArgument(llvm::StringRef(cstr));
+            proc_env.insert(cstr);
           }
           return true;
         }
@@ -939,6 +733,17 @@ static void PackageXPCArguments(xpc_object_t message, const char *prefix,
   }
 }
 
+static void PackageXPCEnvironment(xpc_object_t message, llvm::StringRef prefix,
+                                  const Environment &env) {
+  xpc_dictionary_set_int64(message, (prefix + "Count").str().c_str(),
+                           env.size());
+  size_t i = 0;
+  for (const auto &KV : env) {
+    xpc_dictionary_set_string(message, (prefix + llvm::Twine(i)).str().c_str(),
+                              Environment::compose(KV).c_str());
+  }
+}
+
 /*
  A valid authorizationRef means that
     - there is the LaunchUsingXPCRightName rights in the /etc/authorization
@@ -1045,14 +850,11 @@ static short GetPosixspawnFlags(const ProcessLaunchInfo &launch_info) {
   if (g_use_close_on_exec_flag == eLazyBoolCalculate) {
     g_use_close_on_exec_flag = eLazyBoolNo;
 
-    uint32_t major, minor, update;
-    if (HostInfo::GetOSVersion(major, minor, update)) {
+    llvm::VersionTuple version = HostInfo::GetOSVersion();
+    if (version > llvm::VersionTuple(10, 7)) {
       // Kernel panic if we use the POSIX_SPAWN_CLOEXEC_DEFAULT on 10.7 or
       // earlier
-      if (major > 10 || (major == 10 && minor > 7)) {
-        // Only enable for 10.8 and later OS versions
-        g_use_close_on_exec_flag = eLazyBoolYes;
-      }
+      g_use_close_on_exec_flag = eLazyBoolYes;
     }
   }
 #else
@@ -1141,8 +943,8 @@ static Status LaunchProcessXPC(const char *exe_path,
 
   PackageXPCArguments(message, LauncherXPCServiceArgPrefxKey,
                       launch_info.GetArguments());
-  PackageXPCArguments(message, LauncherXPCServiceEnvPrefxKey,
-                      launch_info.GetEnvironmentEntries());
+  PackageXPCEnvironment(message, LauncherXPCServiceEnvPrefxKey,
+                        launch_info.GetEnvironment());
 
   // Posix spawn stuff.
   xpc_dictionary_set_int64(message, LauncherXPCServiceCPUTypeKey,
@@ -1294,10 +1096,8 @@ static Status LaunchProcessPosixSpawn(const char *exe_path,
     return error;
   }
 
-  // Make a quick class that will cleanup the posix spawn attributes in case
-  // we return in the middle of this function.
-  lldb_utility::CleanUp<posix_spawnattr_t *, int> posix_spawnattr_cleanup(
-      &attr, posix_spawnattr_destroy);
+  // Make sure we clean up the posix spawn attributes before exiting this scope.
+  CleanUp cleanup_attr(posix_spawnattr_destroy, &attr);
 
   sigset_t no_signals;
   sigset_t all_signals;
@@ -1356,8 +1156,7 @@ static Status LaunchProcessPosixSpawn(const char *exe_path,
   const char *tmp_argv[2];
   char *const *argv = const_cast<char *const *>(
       launch_info.GetArguments().GetConstArgumentVector());
-  char *const *envp = const_cast<char *const *>(
-      launch_info.GetEnvironmentEntries().GetConstArgumentVector());
+  Environment::Envp envp = launch_info.GetEnvironment().getEnvp();
   if (argv == NULL) {
     // posix_spawn gets very unhappy if it doesn't have at least the program
     // name in argv[0]. One of the side affects I have noticed is the
@@ -1400,11 +1199,8 @@ static Status LaunchProcessPosixSpawn(const char *exe_path,
       return error;
     }
 
-    // Make a quick class that will cleanup the posix spawn attributes in case
-    // we return in the middle of this function.
-    lldb_utility::CleanUp<posix_spawn_file_actions_t *, int>
-        posix_spawn_file_actions_cleanup(&file_actions,
-                                         posix_spawn_file_actions_destroy);
+    // Make sure we clean up the posix file actions before exiting this scope.
+    CleanUp cleanup_fileact(posix_spawn_file_actions_destroy, &file_actions);
 
     for (size_t i = 0; i < num_file_actions; ++i) {
       const FileAction *launch_file_action =
@@ -1425,7 +1221,8 @@ static Status LaunchProcessPosixSpawn(const char *exe_path,
                "error: {0}, ::posix_spawnp(pid => {1}, path = '{2}', "
                "file_actions = {3}, "
                "attr = {4}, argv = {5}, envp = {6} )",
-               error, result_pid, exe_path, &file_actions, &attr, argv, envp);
+               error, result_pid, exe_path, &file_actions, &attr, argv,
+               envp.get());
       if (log) {
         for (int ii = 0; argv[ii]; ++ii)
           LLDB_LOG(log, "argv[{0}] = '{1}'", ii, argv[ii]);
@@ -1441,7 +1238,7 @@ static Status LaunchProcessPosixSpawn(const char *exe_path,
       LLDB_LOG(log,
                "error: {0}, ::posix_spawnp ( pid => {1}, path = '{2}', "
                "file_actions = NULL, attr = {3}, argv = {4}, envp = {5} )",
-               error, result_pid, exe_path, &attr, argv, envp);
+               error, result_pid, exe_path, &attr, argv, envp.get());
       if (log) {
         for (int ii = 0; argv[ii]; ++ii)
           LLDB_LOG(log, "argv[{0}] = '{1}'", ii, argv[ii]);
@@ -1476,36 +1273,28 @@ static bool ShouldLaunchUsingXPC(ProcessLaunchInfo &launch_info) {
 
 Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
   Status error;
-  char exe_path[PATH_MAX];
-  PlatformSP host_platform_sp(Platform::GetHostPlatform());
-
-  ModuleSpec exe_module_spec(launch_info.GetExecutableFile(),
-                             launch_info.GetArchitecture());
-
-  if (!llvm::sys::fs::is_regular_file(
-          exe_module_spec.GetFileSpec().GetPath())) {
-    lldb::ModuleSP exe_module_sp;
-    error = host_platform_sp->ResolveExecutable(exe_module_spec, exe_module_sp,
-                                                NULL);
-
-    if (error.Fail())
-      return error;
+  FileSpec exe_spec(launch_info.GetExecutableFile());
 
-    if (exe_module_sp)
-      exe_module_spec.GetFileSpec() = exe_module_sp->GetFileSpec();
+  llvm::sys::fs::file_status stats;
+  status(exe_spec.GetPath(), stats);
+  if (!exists(stats)) {
+    exe_spec.ResolvePath();
+    status(exe_spec.GetPath(), stats);
   }
-
-  if (exe_module_spec.GetFileSpec().Exists()) {
-    exe_module_spec.GetFileSpec().GetPath(exe_path, sizeof(exe_path));
-  } else {
-    launch_info.GetExecutableFile().GetPath(exe_path, sizeof(exe_path));
-    error.SetErrorStringWithFormat("executable doesn't exist: '%s'", exe_path);
+  if (!exists(stats)) {
+    exe_spec.ResolveExecutableLocation();
+    status(exe_spec.GetPath(), stats);
+  }
+  if (!exists(stats)) {
+    error.SetErrorStringWithFormatv("executable doesn't exist: '{0}'",
+                                    launch_info.GetExecutableFile());
     return error;
   }
 
   if (launch_info.GetFlags().Test(eLaunchFlagLaunchInTTY)) {
 #if !defined(__arm__) && !defined(__arm64__) && !defined(__aarch64__)
-    return LaunchInNewTerminalWithAppleScript(exe_path, launch_info);
+    return LaunchInNewTerminalWithAppleScript(exe_spec.GetPath().c_str(),
+                                              launch_info);
 #else
     error.SetErrorString("launching a process in a new terminal is not "
                          "supported on iOS devices");
@@ -1516,9 +1305,10 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
   lldb::pid_t pid = LLDB_INVALID_PROCESS_ID;
 
   if (ShouldLaunchUsingXPC(launch_info)) {
-    error = LaunchProcessXPC(exe_path, launch_info, pid);
+    error = LaunchProcessXPC(exe_spec.GetPath().c_str(), launch_info, pid);
   } else {
-    error = LaunchProcessPosixSpawn(exe_path, launch_info, pid);
+    error =
+        LaunchProcessPosixSpawn(exe_spec.GetPath().c_str(), launch_info, pid);
   }
 
   if (pid != LLDB_INVALID_PROCESS_ID) {
@@ -1526,15 +1316,9 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
     launch_info.SetProcessID(pid);
 
     // Make sure we reap any processes we spawn or we will have zombies.
-    if (!launch_info.MonitorProcess()) {
-      const bool monitor_signals = false;
-      Host::MonitorChildProcessCallback callback = nullptr;
-
-      if (!launch_info.GetFlags().Test(lldb::eLaunchFlagDontSetExitStatus))
-        callback = Process::SetProcessExitStatus;
-
-      StartMonitoringChildProcess(callback, pid, monitor_signals);
-    }
+    bool monitoring = launch_info.MonitorProcess();
+    UNUSED_IF_ASSERT_DISABLED(monitoring);
+    assert(monitoring);
   } else {
     // Invalid process ID, something didn't go well
     if (error.Success())
@@ -1546,9 +1330,8 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
 Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
   Status error;
   if (launch_info.GetFlags().Test(eLaunchFlagShellExpandArguments)) {
-    FileSpec expand_tool_spec;
-    if (!HostInfo::GetLLDBPath(lldb::ePathTypeSupportExecutableDir,
-                               expand_tool_spec)) {
+    FileSpec expand_tool_spec = HostInfo::GetSupportExeDir();
+    if (!expand_tool_spec) {
       error.SetErrorString(
           "could not get support executable directory for lldb-argdumper tool");
       return error;
@@ -1583,7 +1366,8 @@ Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
         launch_info.SetWorkingDirectory(working_dir);
       }
     }
-    RunShellCommand(expand_command, cwd, &status, nullptr, &output, 10);
+    RunShellCommand(expand_command, cwd, &status, nullptr, &output,
+                    std::chrono::seconds(10));
 
     if (status != 0) {
       error.SetErrorStringWithFormat("lldb-argdumper exited with error %d",
diff --git a/source/Host/macosx/HostInfoMacOSX.mm b/source/Host/macosx/objcxx/HostInfoMacOSX.mm
index 8774c76ef2dad..a39d26aa31ae4 100644
--- a/source/Host/macosx/HostInfoMacOSX.mm
+++ b/source/Host/macosx/objcxx/HostInfoMacOSX.mm
@@ -7,18 +7,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if !defined(LLDB_DISABLE_PYTHON)
-#include "Plugins/ScriptInterpreter/Python/lldb-python.h"
-#endif
-
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/macosx/HostInfoMacOSX.h"
-#include "lldb/Interpreter/Args.h"
+#include "lldb/Utility/Args.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/SafeMachO.h"
 
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 
 // C++ Includes
@@ -30,7 +27,7 @@
 #include <sys/syslimits.h>
 #include <sys/types.h>
 
-// Objective C/C++ includes
+// Objective-C/C++ includes
 #include <CoreFoundation/CoreFoundation.h>
 #include <Foundation/Foundation.h>
 #include <mach-o/dyld.h>
@@ -75,32 +72,21 @@ bool HostInfoMacOSX::GetOSKernelDescription(std::string &s) {
   return false;
 }
 
-bool HostInfoMacOSX::GetOSVersion(uint32_t &major, uint32_t &minor,
-                                  uint32_t &update) {
-  static uint32_t g_major = 0;
-  static uint32_t g_minor = 0;
-  static uint32_t g_update = 0;
+llvm::VersionTuple HostInfoMacOSX::GetOSVersion() {
+  static llvm::VersionTuple g_version;
 
-  if (g_major == 0) {
+  if (g_version.empty()) {
     @autoreleasepool {
       NSDictionary *version_info = [NSDictionary
           dictionaryWithContentsOfFile:
               @"/System/Library/CoreServices/SystemVersion.plist"];
       NSString *version_value = [version_info objectForKey:@"ProductVersion"];
       const char *version_str = [version_value UTF8String];
-      if (version_str)
-        Args::StringToVersion(llvm::StringRef(version_str), g_major, g_minor,
-                              g_update);
+      g_version.tryParse(version_str);
     }
   }
 
-  if (g_major != 0) {
-    major = g_major;
-    minor = g_minor;
-    update = g_update;
-    return true;
-  }
-  return false;
+  return g_version;
 }
 
 FileSpec HostInfoMacOSX::GetProgramFileSpec() {
@@ -111,13 +97,15 @@ FileSpec HostInfoMacOSX::GetProgramFileSpec() {
     uint32_t len = sizeof(program_fullpath);
     int err = _NSGetExecutablePath(program_fullpath, &len);
     if (err == 0)
-      g_program_filespec.SetFile(program_fullpath, false);
+      g_program_filespec.SetFile(program_fullpath, false,
+                                 FileSpec::Style::native);
     else if (err == -1) {
       char *large_program_fullpath = (char *)::malloc(len + 1);
 
       err = _NSGetExecutablePath(large_program_fullpath, &len);
       if (err == 0)
-        g_program_filespec.SetFile(large_program_fullpath, false);
+        g_program_filespec.SetFile(large_program_fullpath, false,
+                                   FileSpec::Style::native);
 
       ::free(large_program_fullpath);
     }
@@ -126,8 +114,8 @@ FileSpec HostInfoMacOSX::GetProgramFileSpec() {
 }
 
 bool HostInfoMacOSX::ComputeSupportExeDirectory(FileSpec &file_spec) {
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
+  FileSpec lldb_file_spec = GetShlibDir();
+  if (!lldb_file_spec)
     return false;
 
   std::string raw_path = lldb_file_spec.GetPath();
@@ -179,8 +167,8 @@ bool HostInfoMacOSX::ComputeSupportExeDirectory(FileSpec &file_spec) {
 }
 
 bool HostInfoMacOSX::ComputeHeaderDirectory(FileSpec &file_spec) {
-  FileSpec lldb_file_spec;
-  if (!HostInfo::GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
+  FileSpec lldb_file_spec = GetShlibDir();
+  if (!lldb_file_spec)
     return false;
 
   std::string raw_path = lldb_file_spec.GetPath();
@@ -196,58 +184,9 @@ bool HostInfoMacOSX::ComputeHeaderDirectory(FileSpec &file_spec) {
   return true;
 }
 
-bool HostInfoMacOSX::ComputePythonDirectory(FileSpec &file_spec) {
-#ifndef LLDB_DISABLE_PYTHON
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
-    return false;
-
-  std::string raw_path = lldb_file_spec.GetPath();
-
-  size_t framework_pos = raw_path.find("LLDB.framework");
-  if (framework_pos != std::string::npos) {
-    framework_pos += strlen("LLDB.framework");
-    raw_path.resize(framework_pos);
-    raw_path.append("/Resources/Python");
-  } else {
-    llvm::SmallString<256> python_version_dir;
-    llvm::raw_svector_ostream os(python_version_dir);
-    os << "/python" << PY_MAJOR_VERSION << '.' << PY_MINOR_VERSION
-       << "/site-packages";
-
-    // We may get our string truncated. Should we protect this with an assert?
-    raw_path.append(python_version_dir.c_str());
-  }
-  file_spec.GetDirectory().SetString(
-      llvm::StringRef(raw_path.c_str(), raw_path.size()));
-  return true;
-#else
-  return false;
-#endif
-}
-
-bool HostInfoMacOSX::ComputeClangDirectory(FileSpec &file_spec) {
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
-    return false;
-
-  std::string raw_path = lldb_file_spec.GetPath();
-
-  size_t framework_pos = raw_path.find("LLDB.framework");
-  if (framework_pos == std::string::npos)
-    return HostInfoPosix::ComputeClangDirectory(file_spec);
-  
-  framework_pos += strlen("LLDB.framework");
-  raw_path.resize(framework_pos);
-  raw_path.append("/Resources/Clang");
-  
-  file_spec.SetFile(raw_path.c_str(), true);
-  return true;
-}
-
 bool HostInfoMacOSX::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
+  FileSpec lldb_file_spec = GetShlibDir();
+  if (!lldb_file_spec)
     return false;
 
   std::string raw_path = lldb_file_spec.GetPath();
diff --git a/source/Host/macosx/HostThreadMacOSX.mm b/source/Host/macosx/objcxx/HostThreadMacOSX.mm
index c5051cdf30d77..c5051cdf30d77 100644
--- a/source/Host/macosx/HostThreadMacOSX.mm
+++ b/source/Host/macosx/objcxx/HostThreadMacOSX.mm
diff --git a/source/Host/netbsd/Host.cpp b/source/Host/netbsd/Host.cpp
index d927f95f06753..bfd5a74ffcc21 100644
--- a/source/Host/netbsd/Host.cpp
+++ b/source/Host/netbsd/Host.cpp
@@ -25,12 +25,9 @@
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
-#include "lldb/Core/Module.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
-#include "lldb/Target/Platform.h"
 #include "lldb/Target/Process.h"
-#include "lldb/Utility/CleanUp.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
 #include "lldb/Utility/Endian.h"
@@ -48,14 +45,7 @@ extern char **environ;
 using namespace lldb;
 using namespace lldb_private;
 
-size_t Host::GetEnvironment(StringList &env) {
-  char **host_env = environ;
-  char *env_entry;
-  size_t i;
-  for (i = 0; (env_entry = host_env[i]) != NULL; ++i)
-    env.AppendString(env_entry);
-  return i;
-}
+Environment Host::GetEnvironment() { return Environment(environ); }
 
 static bool GetNetBSDProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
                                  ProcessInstanceInfo &process_info) {
@@ -80,7 +70,8 @@ static bool GetNetBSDProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
   if (!cstr)
     return false;
 
-  process_info.GetExecutableFile().SetFile(cstr, false);
+  process_info.GetExecutableFile().SetFile(cstr, false,
+                                           FileSpec::Style::native);
 
   if (!(match_info_ptr == NULL ||
         NameMatches(process_info.GetExecutableFile().GetFilename().GetCString(),
@@ -202,9 +193,8 @@ uint32_t Host::FindProcesses(const ProcessInstanceInfoMatch &match_info,
       continue;
 
     // Every thread is a process in NetBSD, but all the threads of a single
-    // process have the same pid. Do not store the process info in the
-    // result list if a process with given identifier is already registered
-    // there.
+    // process have the same pid. Do not store the process info in the result
+    // list if a process with given identifier is already registered there.
     if (proc_kinfo[i].p_nlwps > 1) {
       bool already_registered = false;
       for (size_t pi = 0; pi < process_infos.GetSize(); pi++) {
diff --git a/source/Host/netbsd/HostInfoNetBSD.cpp b/source/Host/netbsd/HostInfoNetBSD.cpp
index 428183bbe2c3f..dfbce310509dc 100644
--- a/source/Host/netbsd/HostInfoNetBSD.cpp
+++ b/source/Host/netbsd/HostInfoNetBSD.cpp
@@ -21,30 +21,26 @@
 
 using namespace lldb_private;
 
-bool HostInfoNetBSD::GetOSVersion(uint32_t &major, uint32_t &minor,
-                                  uint32_t &update) {
+llvm::VersionTuple HostInfoNetBSD::GetOSVersion() {
   struct utsname un;
 
   ::memset(&un, 0, sizeof(un));
   if (::uname(&un) < 0)
-    return false;
+    return llvm::VersionTuple();
 
   /* Accept versions like 7.99.21 and 6.1_STABLE */
+  uint32_t major, minor, update;
   int status = ::sscanf(un.release, "%" PRIu32 ".%" PRIu32 ".%" PRIu32, &major,
                         &minor, &update);
   switch (status) {
-  case 0:
-    return false;
   case 1:
-    minor = 0;
-  /* FALLTHROUGH */
+    return llvm::VersionTuple(major);
   case 2:
-    update = 0;
-  /* FALLTHROUGH */
+    return llvm::VersionTuple(major, minor);
   case 3:
-  default:
-    return true;
+    return llvm::VersionTuple(major, minor, update);
   }
+  return llvm::VersionTuple();
 }
 
 bool HostInfoNetBSD::GetOSBuildString(std::string &s) {
@@ -89,7 +85,7 @@ FileSpec HostInfoNetBSD::GetProgramFileSpec() {
 
     len = sizeof(path);
     if (sysctl(name, __arraycount(name), path, &len, NULL, 0) != -1) {
-        g_program_filespec.SetFile(path, false);
+      g_program_filespec.SetFile(path, false, FileSpec::Style::native);
     }
   }
   return g_program_filespec;
diff --git a/source/Host/openbsd/Host.cpp b/source/Host/openbsd/Host.cpp
index 0535256b9aa1f..49e9c290a027e 100644
--- a/source/Host/openbsd/Host.cpp
+++ b/source/Host/openbsd/Host.cpp
@@ -22,12 +22,9 @@
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
-#include "lldb/Core/Module.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
-#include "lldb/Target/Platform.h"
 #include "lldb/Target/Process.h"
-#include "lldb/Utility/CleanUp.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
 #include "lldb/Utility/Endian.h"
@@ -45,16 +42,17 @@ extern char **environ;
 using namespace lldb;
 using namespace lldb_private;
 
-size_t Host::GetEnvironment(StringList &env) {
+Environment Host::GetEnvironment() {
+  Environment env;
   char *v;
   char **var = environ;
   for (; var != NULL && *var != NULL; ++var) {
     v = strchr(*var, (int)'-');
     if (v == NULL)
       continue;
-    env.AppendString(v);
+    env.insert(v);
   }
-  return env.GetSize();
+  return env;
 }
 
 static bool
@@ -74,7 +72,8 @@ GetOpenBSDProcessArgs(const ProcessInstanceInfoMatch *match_info_ptr,
 
       cstr = data.GetCStr(&offset);
       if (cstr) {
-        process_info.GetExecutableFile().SetFile(cstr, false);
+        process_info.GetExecutableFile().SetFile(cstr, false,
+                                                 FileSpec::Style::native);
 
         if (!(match_info_ptr == NULL ||
               NameMatches(
diff --git a/source/Host/posix/ConnectionFileDescriptorPosix.cpp b/source/Host/posix/ConnectionFileDescriptorPosix.cpp
index 3797650105ce3..c21bb786a8962 100644
--- a/source/Host/posix/ConnectionFileDescriptorPosix.cpp
+++ b/source/Host/posix/ConnectionFileDescriptorPosix.cpp
@@ -189,15 +189,14 @@ ConnectionStatus ConnectionFileDescriptor::Connect(llvm::StringRef path,
     }
 #ifndef LLDB_DISABLE_POSIX
     else if ((addr = GetURLAddress(path, FD_SCHEME))) {
-      // Just passing a native file descriptor within this current process
-      // that is already opened (possibly from a service or other source).
+      // Just passing a native file descriptor within this current process that
+      // is already opened (possibly from a service or other source).
       int fd = -1;
 
       if (!addr->getAsInteger(0, fd)) {
-        // We have what looks to be a valid file descriptor, but we
-        // should make sure it is. We currently are doing this by trying to
-        // get the flags from the file descriptor and making sure it
-        // isn't a bad fd.
+        // We have what looks to be a valid file descriptor, but we should make
+        // sure it is. We currently are doing this by trying to get the flags
+        // from the file descriptor and making sure it isn't a bad fd.
         errno = 0;
         int flags = ::fcntl(fd, F_GETFL, 0);
         if (flags == -1 || errno == EBADF) {
@@ -208,20 +207,18 @@ ConnectionStatus ConnectionFileDescriptor::Connect(llvm::StringRef path,
           m_write_sp.reset();
           return eConnectionStatusError;
         } else {
-          // Don't take ownership of a file descriptor that gets passed
-          // to us since someone else opened the file descriptor and
-          // handed it to us.
+          // Don't take ownership of a file descriptor that gets passed to us
+          // since someone else opened the file descriptor and handed it to us.
           // TODO: Since are using a URL to open connection we should
-          // eventually parse options using the web standard where we
-          // have "fd://123?opt1=value;opt2=value" and we can have an
-          // option be "owns=1" or "owns=0" or something like this to
-          // allow us to specify this. For now, we assume we must
-          // assume we don't own it.
+          // eventually parse options using the web standard where we have
+          // "fd://123?opt1=value;opt2=value" and we can have an option be
+          // "owns=1" or "owns=0" or something like this to allow us to specify
+          // this. For now, we assume we must assume we don't own it.
 
           std::unique_ptr<TCPSocket> tcp_socket;
           tcp_socket.reset(new TCPSocket(fd, false, false));
-          // Try and get a socket option from this file descriptor to
-          // see if this is a socket and set m_is_socket accordingly.
+          // Try and get a socket option from this file descriptor to see if
+          // this is a socket and set m_is_socket accordingly.
           int resuse;
           bool is_socket =
               !!tcp_socket->GetOption(SOL_SOCKET, SO_REUSEADDR, resuse);
@@ -320,13 +317,11 @@ ConnectionStatus ConnectionFileDescriptor::Disconnect(Status *error_ptr) {
       m_read_sp->GetFdType() == IOObject::eFDTypeSocket)
     static_cast<Socket &>(*m_read_sp).PreDisconnect();
 
-  // Try to get the ConnectionFileDescriptor's mutex.  If we fail, that is quite
-  // likely
-  // because somebody is doing a blocking read on our file descriptor.  If
-  // that's the case,
-  // then send the "q" char to the command file channel so the read will wake up
-  // and the connection
-  // will then know to shut down.
+  // Try to get the ConnectionFileDescriptor's mutex.  If we fail, that is
+  // quite likely because somebody is doing a blocking read on our file
+  // descriptor.  If that's the case, then send the "q" char to the command
+  // file channel so the read will wake up and the connection will then know to
+  // shut down.
 
   m_shutting_down = true;
 
@@ -430,11 +425,11 @@ size_t ConnectionFileDescriptor::Read(void *dst, size_t dst_len,
     case EINVAL:  // The pointer associated with fildes was negative.
     case EIO:     // An I/O error occurred while reading from the file system.
                   // The process group is orphaned.
-                  // The file is a regular file, nbyte is greater than 0,
-                  // the starting position is before the end-of-file, and
-                  // the starting position is greater than or equal to the
-                  // offset maximum established for the open file
-                  // descriptor associated with fildes.
+                  // The file is a regular file, nbyte is greater than 0, the
+                  // starting position is before the end-of-file, and the
+                  // starting position is greater than or equal to the offset
+                  // maximum established for the open file descriptor
+                  // associated with fildes.
     case EISDIR:  // An attempt is made to read a directory.
     case ENOBUFS: // An attempt to allocate a memory buffer fails.
     case ENOMEM:  // Insufficient memory is available.
@@ -550,15 +545,15 @@ ConnectionStatus
 ConnectionFileDescriptor::BytesAvailable(const Timeout<std::micro> &timeout,
                                          Status *error_ptr) {
   // Don't need to take the mutex here separately since we are only called from
-  // Read.  If we
-  // ever get used more generally we will need to lock here as well.
+  // Read.  If we ever get used more generally we will need to lock here as
+  // well.
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_CONNECTION));
   LLDB_LOG(log, "this = {0}, timeout = {1}", this, timeout);
 
-  // Make a copy of the file descriptors to make sure we don't
-  // have another thread change these values out from under us
-  // and cause problems in the loop below where like in FS_SET()
+  // Make a copy of the file descriptors to make sure we don't have another
+  // thread change these values out from under us and cause problems in the
+  // loop below where like in FS_SET()
   const IOObject::WaitableHandle handle = m_read_sp->GetWaitableHandle();
   const int pipe_fd = m_pipe.GetReadFileDescriptor();
 
@@ -570,10 +565,9 @@ ConnectionFileDescriptor::BytesAvailable(const Timeout<std::micro> &timeout,
     select_helper.FDSetRead(handle);
 #if defined(_MSC_VER)
     // select() won't accept pipes on Windows.  The entire Windows codepath
-    // needs to be
-    // converted over to using WaitForMultipleObjects and event HANDLEs, but for
-    // now at least
-    // this will allow ::select() to not return an error.
+    // needs to be converted over to using WaitForMultipleObjects and event
+    // HANDLEs, but for now at least this will allow ::select() to not return
+    // an error.
     const bool have_pipe_fd = false;
 #else
     const bool have_pipe_fd = pipe_fd >= 0;
@@ -603,11 +597,10 @@ ConnectionFileDescriptor::BytesAvailable(const Timeout<std::micro> &timeout,
           return eConnectionStatusTimedOut;
 
         case EAGAIN: // The kernel was (perhaps temporarily) unable to
-                     // allocate the requested number of file descriptors,
-                     // or we have non-blocking IO
+                     // allocate the requested number of file descriptors, or
+                     // we have non-blocking IO
         case EINTR:  // A signal was delivered before the time limit
-          // expired and before any of the selected events
-          // occurred.
+          // expired and before any of the selected events occurred.
           break; // Lets keep reading to until we timeout
         }
       } else {
@@ -615,8 +608,8 @@ ConnectionFileDescriptor::BytesAvailable(const Timeout<std::micro> &timeout,
           return eConnectionStatusSuccess;
 
         if (select_helper.FDIsSetRead(pipe_fd)) {
-          // There is an interrupt or exit command in the command pipe
-          // Read the data from that pipe:
+          // There is an interrupt or exit command in the command pipe Read the
+          // data from that pipe:
           char c;
 
           ssize_t bytes_read = llvm::sys::RetryAfterSignal(-1, ::read, pipe_fd, &c, 1);
@@ -753,14 +746,10 @@ ConnectionStatus ConnectionFileDescriptor::ConnectUDP(llvm::StringRef s,
   return eConnectionStatusSuccess;
 }
 
-uint16_t ConnectionFileDescriptor::GetListeningPort(uint32_t timeout_sec) {
-  uint16_t bound_port = 0;
-  if (timeout_sec == UINT32_MAX)
-    m_port_predicate.WaitForValueNotEqualTo(0, bound_port);
-  else
-    m_port_predicate.WaitForValueNotEqualTo(0, bound_port,
-                                            std::chrono::seconds(timeout_sec));
-  return bound_port;
+uint16_t
+ConnectionFileDescriptor::GetListeningPort(const Timeout<std::micro> &timeout) {
+  auto Result = m_port_predicate.WaitForValueNotEqualTo(0, timeout);
+  return Result ? *Result : 0;
 }
 
 bool ConnectionFileDescriptor::GetChildProcessesInherit() const {
diff --git a/source/Host/posix/FileSystem.cpp b/source/Host/posix/FileSystem.cpp
index 3ece0677f991d..60be642df6087 100644
--- a/source/Host/posix/FileSystem.cpp
+++ b/source/Host/posix/FileSystem.cpp
@@ -16,11 +16,6 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
-#ifdef __linux__
-#include <linux/magic.h>
-#include <sys/mount.h>
-#include <sys/statfs.h>
-#endif
 #if defined(__NetBSD__)
 #include <sys/statvfs.h>
 #endif
@@ -52,7 +47,7 @@ Status FileSystem::Readlink(const FileSpec &src, FileSpec &dst) {
     error.SetErrorToErrno();
   else {
     buf[count] = '\0'; // Success
-    dst.SetFile(buf, false);
+    dst.SetFile(buf, false, FileSpec::Style::native);
   }
   return error;
 }
diff --git a/source/Host/posix/HostInfoPosix.cpp b/source/Host/posix/HostInfoPosix.cpp
index da9e1fb366cc2..62c70fa3edc12 100644
--- a/source/Host/posix/HostInfoPosix.cpp
+++ b/source/Host/posix/HostInfoPosix.cpp
@@ -7,15 +7,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if !defined(LLDB_DISABLE_PYTHON)
-#include "Plugins/ScriptInterpreter/Python/lldb-python.h"
-#endif
-
 #include "lldb/Host/posix/HostInfoPosix.h"
 #include "lldb/Utility/Log.h"
 
-#include "clang/Basic/Version.h"
-#include "clang/Config/config.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Path.h"
@@ -103,8 +97,7 @@ const char *HostInfoPosix::LookupGroupName(uint32_t gid,
     }
   } else {
     // The threadsafe version isn't currently working for me on darwin, but the
-    // non-threadsafe version
-    // is, so I am calling it below.
+    // non-threadsafe version is, so I am calling it below.
     group_info_ptr = ::getgrgid(gid);
     if (group_info_ptr) {
       group_name.assign(group_info_ptr->gr_name);
@@ -132,8 +125,8 @@ bool HostInfoPosix::ComputePathRelativeToLibrary(FileSpec &file_spec,
                                                  llvm::StringRef dir) {
   Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
 
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
+  FileSpec lldb_file_spec = GetShlibDir();
+  if (!lldb_file_spec)
     return false;
 
   std::string raw_path = lldb_file_spec.GetPath();
@@ -141,8 +134,8 @@ bool HostInfoPosix::ComputePathRelativeToLibrary(FileSpec &file_spec,
   llvm::StringRef parent_path = llvm::sys::path::parent_path(raw_path);
 
   // Most Posix systems (e.g. Linux/*BSD) will attempt to replace a */lib with
-  // */bin as the base directory for helper exe programs.  This will fail if the
-  // /lib and /bin directories are rooted in entirely different trees.
+  // */bin as the base directory for helper exe programs.  This will fail if
+  // the /lib and /bin directories are rooted in entirely different trees.
   if (log)
     log->Printf("HostInfoPosix::ComputePathRelativeToLibrary() attempting to "
                 "derive the %s path from this path: %s",
@@ -169,59 +162,12 @@ bool HostInfoPosix::ComputeSupportExeDirectory(FileSpec &file_spec) {
   return ComputePathRelativeToLibrary(file_spec, "/bin");
 }
 
-bool HostInfoPosix::ComputeClangDirectory(FileSpec &file_spec) {
-  return ComputePathRelativeToLibrary(
-      file_spec, (llvm::Twine("/lib") + CLANG_LIBDIR_SUFFIX + "/clang/" +
-                  CLANG_VERSION_STRING)
-                     .str());
-}
-
 bool HostInfoPosix::ComputeHeaderDirectory(FileSpec &file_spec) {
   FileSpec temp_file("/opt/local/include/lldb", false);
   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
   return true;
 }
 
-bool HostInfoPosix::ComputePythonDirectory(FileSpec &file_spec) {
-#ifndef LLDB_DISABLE_PYTHON
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
-    return false;
-
-  char raw_path[PATH_MAX];
-  lldb_file_spec.GetPath(raw_path, sizeof(raw_path));
-
-#if defined(LLDB_PYTHON_RELATIVE_LIBDIR)
-  // Build the path by backing out of the lib dir, then building
-  // with whatever the real python interpreter uses.  (e.g. lib
-  // for most, lib64 on RHEL x86_64).
-  char python_path[PATH_MAX];
-  ::snprintf(python_path, sizeof(python_path), "%s/../%s", raw_path,
-             LLDB_PYTHON_RELATIVE_LIBDIR);
-
-  char final_path[PATH_MAX];
-  realpath(python_path, final_path);
-  file_spec.GetDirectory().SetCString(final_path);
-
-  return true;
-#else
-  llvm::SmallString<256> python_version_dir;
-  llvm::raw_svector_ostream os(python_version_dir);
-  os << "/python" << PY_MAJOR_VERSION << '.' << PY_MINOR_VERSION
-     << "/site-packages";
-
-  // We may get our string truncated. Should we protect this with an assert?
-  ::strncat(raw_path, python_version_dir.c_str(),
-            sizeof(raw_path) - strlen(raw_path) - 1);
-
-  file_spec.GetDirectory().SetCString(raw_path);
-  return true;
-#endif
-#else
-  return false;
-#endif
-}
-
 bool HostInfoPosix::GetEnvironmentVar(const std::string &var_name,
                                       std::string &var) {
   if (const char *pvar = ::getenv(var_name.c_str())) {
diff --git a/source/Host/posix/HostThreadPosix.cpp b/source/Host/posix/HostThreadPosix.cpp
index 71abb76dc600b..13de42f763ec7 100644
--- a/source/Host/posix/HostThreadPosix.cpp
+++ b/source/Host/posix/HostThreadPosix.cpp
@@ -41,14 +41,11 @@ Status HostThreadPosix::Join(lldb::thread_result_t *result) {
 Status HostThreadPosix::Cancel() {
   Status error;
   if (IsJoinable()) {
-#ifndef __ANDROID__
 #ifndef __FreeBSD__
     llvm_unreachable("someone is calling HostThread::Cancel()");
-#endif
+#else
     int err = ::pthread_cancel(m_thread);
     error.SetError(err, eErrorTypePOSIX);
-#else
-    error.SetErrorString("HostThreadPosix::Cancel() not supported on Android");
 #endif
   }
   return error;
diff --git a/source/Host/posix/PipePosix.cpp b/source/Host/posix/PipePosix.cpp
index da99fd702424e..b321cad642758 100644
--- a/source/Host/posix/PipePosix.cpp
+++ b/source/Host/posix/PipePosix.cpp
@@ -127,18 +127,14 @@ Status PipePosix::CreateWithUniqueName(llvm::StringRef prefix,
                                        llvm::SmallVectorImpl<char> &name) {
   llvm::SmallString<PATH_MAX> named_pipe_path;
   llvm::SmallString<PATH_MAX> pipe_spec((prefix + ".%%%%%%").str());
-  FileSpec tmpdir_file_spec;
-  tmpdir_file_spec.Clear();
-  if (HostInfo::GetLLDBPath(ePathTypeLLDBTempSystemDir, tmpdir_file_spec)) {
-    tmpdir_file_spec.AppendPathComponent(pipe_spec.c_str());
-  } else {
+  FileSpec tmpdir_file_spec = HostInfo::GetProcessTempDir();
+  if (!tmpdir_file_spec)
     tmpdir_file_spec.AppendPathComponent("/tmp");
-    tmpdir_file_spec.AppendPathComponent(pipe_spec.c_str());
-  }
+  tmpdir_file_spec.AppendPathComponent(pipe_spec);
 
   // It's possible that another process creates the target path after we've
-  // verified it's available but before we create it, in which case we
-  // should try again.
+  // verified it's available but before we create it, in which case we should
+  // try again.
   Status error;
   do {
     llvm::sys::fs::createUniqueFile(tmpdir_file_spec.GetPath(),
diff --git a/source/Host/posix/ProcessLauncherPosixFork.cpp b/source/Host/posix/ProcessLauncherPosixFork.cpp
index ac1d9011c2b78..46ce3e3d224f6 100644
--- a/source/Host/posix/ProcessLauncherPosixFork.cpp
+++ b/source/Host/posix/ProcessLauncherPosixFork.cpp
@@ -38,17 +38,12 @@
 using namespace lldb;
 using namespace lldb_private;
 
-static void FixupEnvironment(Args &env) {
+static void FixupEnvironment(Environment &env) {
 #ifdef __ANDROID__
   // If there is no PATH variable specified inside the environment then set the
   // path to /system/bin. It is required because the default path used by
   // execve() is wrong on android.
-  static const char *path = "PATH=";
-  for (auto &entry : env.entries()) {
-    if (entry.ref.startswith(path))
-      return;
-  }
-  env.AppendArgument(llvm::StringRef("PATH=/system/bin"));
+  env.try_emplace("PATH", "/system/bin");
 #endif
 }
 
@@ -95,10 +90,6 @@ static void DupDescriptor(int error_fd, const FileSpec &file_spec, int fd,
 
 static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
                                               const ProcessLaunchInfo &info) {
-  // Do not inherit setgid powers.
-  if (setgid(getgid()) != 0)
-    ExitWithError(error_fd, "setgid");
-
   if (info.GetFlags().Test(eLaunchFlagLaunchInSeparateProcessGroup)) {
     if (setpgid(0, 0) != 0)
       ExitWithError(error_fd, "setpgid");
@@ -132,23 +123,26 @@ static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
     ExitWithError(error_fd, "chdir");
 
   DisableASLRIfRequested(error_fd, info);
-  Args env = info.GetEnvironmentEntries();
+  Environment env = info.GetEnvironment();
   FixupEnvironment(env);
-  const char **envp = env.GetConstArgumentVector();
+  Environment::Envp envp = env.getEnvp();
 
-  // Clear the signal mask to prevent the child from being affected by
-  // any masking done by the parent.
+  // Clear the signal mask to prevent the child from being affected by any
+  // masking done by the parent.
   sigset_t set;
   if (sigemptyset(&set) != 0 ||
       pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
     ExitWithError(error_fd, "pthread_sigmask");
 
   if (info.GetFlags().Test(eLaunchFlagDebug)) {
+    // Do not inherit setgid powers.
+    if (setgid(getgid()) != 0)
+      ExitWithError(error_fd, "setgid");
+
     // HACK:
     // Close everything besides stdin, stdout, and stderr that has no file
     // action to avoid leaking. Only do this when debugging, as elsewhere we
-    // actually rely on
-    // passing open descriptors to child processes.
+    // actually rely on passing open descriptors to child processes.
     for (int fd = 3; fd < sysconf(_SC_OPEN_MAX); ++fd)
       if (!info.GetFileActionForFD(fd) && fd != error_fd)
         close(fd);
@@ -159,26 +153,20 @@ static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
   }
 
   // Execute.  We should never return...
-  execve(argv[0], const_cast<char *const *>(argv),
-         const_cast<char *const *>(envp));
+  execve(argv[0], const_cast<char *const *>(argv), envp);
 
 #if defined(__linux__)
   if (errno == ETXTBSY) {
-    // On android M and earlier we can get this error because the adb deamon can
-    // hold a write
-    // handle on the executable even after it has finished uploading it. This
-    // state lasts
-    // only a short time and happens only when there are many concurrent adb
-    // commands being
-    // issued, such as when running the test suite. (The file remains open when
-    // someone does
-    // an "adb shell" command in the fork() child before it has had a chance to
-    // exec.) Since
-    // this state should clear up quickly, wait a while and then give it one
-    // more go.
+    // On android M and earlier we can get this error because the adb deamon
+    // can hold a write handle on the executable even after it has finished
+    // uploading it. This state lasts only a short time and happens only when
+    // there are many concurrent adb commands being issued, such as when
+    // running the test suite. (The file remains open when someone does an "adb
+    // shell" command in the fork() child before it has had a chance to exec.)
+    // Since this state should clear up quickly, wait a while and then give it
+    // one more go.
     usleep(50000);
-    execve(argv[0], const_cast<char *const *>(argv),
-           const_cast<char *const *>(envp));
+    execve(argv[0], const_cast<char *const *>(argv), envp);
   }
 #endif
 
diff --git a/source/Host/windows/ConnectionGenericFileWindows.cpp b/source/Host/windows/ConnectionGenericFileWindows.cpp
index 41bdb5f41fb6a..e59e190dcb2d5 100644
--- a/source/Host/windows/ConnectionGenericFileWindows.cpp
+++ b/source/Host/windows/ConnectionGenericFileWindows.cpp
@@ -21,12 +21,10 @@ using namespace lldb_private;
 
 namespace {
 // This is a simple helper class to package up the information needed to return
-// from a Read/Write
-// operation function.  Since there is a lot of code to be run before exit
-// regardless of whether the
-// operation succeeded or failed, combined with many possible return paths, this
-// is the cleanest
-// way to represent it.
+// from a Read/Write operation function.  Since there is a lot of code to be
+// run before exit regardless of whether the operation succeeded or failed,
+// combined with many possible return paths, this is the cleanest way to
+// represent it.
 class ReturnInfo {
 public:
   void Set(size_t bytes, ConnectionStatus status, DWORD error_code) {
@@ -78,11 +76,9 @@ void ConnectionGenericFile::InitializeEventHandles() {
   m_event_handles[kInterruptEvent] = CreateEvent(NULL, FALSE, FALSE, NULL);
 
   // Note, we should use a manual reset event for the hEvent argument of the
-  // OVERLAPPED.  This
-  // is because both WaitForMultipleObjects and GetOverlappedResult (if you set
-  // the bWait
-  // argument to TRUE) will wait for the event to be signalled.  If we use an
-  // auto-reset event,
+  // OVERLAPPED.  This is because both WaitForMultipleObjects and
+  // GetOverlappedResult (if you set the bWait argument to TRUE) will wait for
+  // the event to be signalled.  If we use an auto-reset event,
   // WaitForMultipleObjects will reset the event, return successfully, and then
   // GetOverlappedResult will block since the event is no longer signalled.
   m_event_handles[kBytesAvailableEvent] =
@@ -147,8 +143,7 @@ lldb::ConnectionStatus ConnectionGenericFile::Disconnect(Status *error_ptr) {
     return eConnectionStatusSuccess;
 
   // Reset the handle so that after we unblock any pending reads, subsequent
-  // calls to Read() will
-  // see a disconnected state.
+  // calls to Read() will see a disconnected state.
   HANDLE old_file = m_file;
   m_file = INVALID_HANDLE_VALUE;
 
@@ -157,8 +152,7 @@ lldb::ConnectionStatus ConnectionGenericFile::Disconnect(Status *error_ptr) {
   ::CancelIoEx(old_file, &m_overlapped);
 
   // Close the file handle if we owned it, but don't close the event handles.
-  // We could always
-  // reconnect with the same Connection instance.
+  // We could always reconnect with the same Connection instance.
   if (m_owns_file)
     ::CloseHandle(old_file);
 
@@ -190,8 +184,7 @@ size_t ConnectionGenericFile::Read(void *dst, size_t dst_len,
   if (result || ::GetLastError() == ERROR_IO_PENDING) {
     if (!result) {
       // The expected return path.  The operation is pending.  Wait for the
-      // operation to complete
-      // or be interrupted.
+      // operation to complete or be interrupted.
       DWORD milliseconds =
           timeout
               ? std::chrono::duration_cast<std::chrono::milliseconds>(*timeout)
@@ -219,11 +212,9 @@ size_t ConnectionGenericFile::Read(void *dst, size_t dst_len,
     // The data is ready.  Figure out how much was read and return;
     if (!::GetOverlappedResult(m_file, &m_overlapped, &bytes_read, FALSE)) {
       DWORD result_error = ::GetLastError();
-      // ERROR_OPERATION_ABORTED occurs when someone calls Disconnect() during a
-      // blocking read.
-      // This triggers a call to CancelIoEx, which causes the operation to
-      // complete and the
-      // result to be ERROR_OPERATION_ABORTED.
+      // ERROR_OPERATION_ABORTED occurs when someone calls Disconnect() during
+      // a blocking read. This triggers a call to CancelIoEx, which causes the
+      // operation to complete and the result to be ERROR_OPERATION_ABORTED.
       if (result_error == ERROR_HANDLE_EOF ||
           result_error == ERROR_OPERATION_ABORTED ||
           result_error == ERROR_BROKEN_PIPE)
@@ -250,9 +241,9 @@ finish:
   if (error_ptr)
     *error_ptr = return_info.GetError();
 
-  // kBytesAvailableEvent is a manual reset event.  Make sure it gets reset here
-  // so that any
-  // subsequent operations don't immediately see bytes available.
+  // kBytesAvailableEvent is a manual reset event.  Make sure it gets reset
+  // here so that any subsequent operations don't immediately see bytes
+  // available.
   ResetEvent(m_event_handles[kBytesAvailableEvent]);
 
   IncrementFilePointer(return_info.GetBytes());
@@ -284,7 +275,8 @@ size_t ConnectionGenericFile::Write(const void *src, size_t src_len,
 
   m_overlapped.hEvent = NULL;
 
-  // Writes are not interruptible like reads are, so just block until it's done.
+  // Writes are not interruptible like reads are, so just block until it's
+  // done.
   result = ::WriteFile(m_file, src, src_len, NULL, &m_overlapped);
   if (!result && ::GetLastError() != ERROR_IO_PENDING) {
     return_info.Set(0, eConnectionStatusError, ::GetLastError());
diff --git a/source/Host/windows/EditLineWin.cpp b/source/Host/windows/EditLineWin.cpp
index 133cd62254679..3bccc4e1a2c9c 100644
--- a/source/Host/windows/EditLineWin.cpp
+++ b/source/Host/windows/EditLineWin.cpp
@@ -316,8 +316,8 @@ int el_get(EditLine *el, int code, ...) {
 }
 
 int el_source(EditLine *el, const char *file) {
-  // init edit line by reading the contents of 'file'
-  // nothing to do here on windows...
+  // init edit line by reading the contents of 'file' nothing to do here on
+  // windows...
   return 0;
 }
 
@@ -342,8 +342,8 @@ void history_end(History *) {
 }
 
 int history(History *, HistEvent *, int op, ...) {
-  // perform operation 'op' on the history list with
-  // optional arguments as needed by the operation.
+  // perform operation 'op' on the history list with optional arguments as
+  // needed by the operation.
   return 0;
 }
 
diff --git a/source/Host/windows/FileSystem.cpp b/source/Host/windows/FileSystem.cpp
index 02b7e550f86cd..9309b89f2baf8 100644
--- a/source/Host/windows/FileSystem.cpp
+++ b/source/Host/windows/FileSystem.cpp
@@ -75,7 +75,7 @@ Status FileSystem::Readlink(const FileSpec &src, FileSpec &dst) {
   else if (!llvm::convertWideToUTF8(buf.data(), path))
     error.SetErrorString(PATH_CONVERSION_ERROR);
   else
-    dst.SetFile(path, false);
+    dst.SetFile(path, false, FileSpec::Style::native);
 
   ::CloseHandle(h);
   return error;
diff --git a/source/Host/windows/Host.cpp b/source/Host/windows/Host.cpp
index 4458ce25e6079..cc6c454d36b11 100644
--- a/source/Host/windows/Host.cpp
+++ b/source/Host/windows/Host.cpp
@@ -35,8 +35,7 @@ using namespace lldb_private;
 namespace {
 bool GetTripleForProcess(const FileSpec &executable, llvm::Triple &triple) {
   // Open the PE File as a binary file, and parse just enough information to
-  // determine the
-  // machine type.
+  // determine the machine type.
   File imageBinary(executable.GetPath().c_str(), File::eOpenOptionRead,
                    lldb::eFilePermissionsUserRead);
   imageBinary.SeekFromStart(0x3c);
@@ -63,8 +62,8 @@ bool GetTripleForProcess(const FileSpec &executable, llvm::Triple &triple) {
 }
 
 bool GetExecutableForProcess(const AutoHandle &handle, std::string &path) {
-  // Get the process image path.  MAX_PATH isn't long enough, paths can actually
-  // be up to 32KB.
+  // Get the process image path.  MAX_PATH isn't long enough, paths can
+  // actually be up to 32KB.
   std::vector<wchar_t> buffer(PATH_MAX);
   DWORD dwSize = buffer.size();
   if (!::QueryFullProcessImageNameW(handle.get(), 0, &buffer[0], &dwSize))
@@ -75,10 +74,9 @@ bool GetExecutableForProcess(const AutoHandle &handle, std::string &path) {
 void GetProcessExecutableAndTriple(const AutoHandle &handle,
                                    ProcessInstanceInfo &process) {
   // We may not have permissions to read the path from the process.  So start
-  // off by
-  // setting the executable file to whatever Toolhelp32 gives us, and then try
-  // to
-  // enhance this with more detailed information, but fail gracefully.
+  // off by setting the executable file to whatever Toolhelp32 gives us, and
+  // then try to enhance this with more detailed information, but fail
+  // gracefully.
   std::string executable;
   llvm::Triple triple;
   triple.setVendor(llvm::Triple::PC);
@@ -124,7 +122,7 @@ FileSpec Host::GetModuleFileSpecForHostAddress(const void *host_addr) {
   std::string path;
   if (!llvm::convertWideToUTF8(buffer.data(), path))
     return module_filespec;
-  module_filespec.SetFile(path, false);
+  module_filespec.SetFile(path, false, FileSpec::Style::native);
   return module_filespec;
 }
 
@@ -184,9 +182,8 @@ HostThread Host::StartMonitoringChildProcess(
 Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
   Status error;
   if (launch_info.GetFlags().Test(eLaunchFlagShellExpandArguments)) {
-    FileSpec expand_tool_spec;
-    if (!HostInfo::GetLLDBPath(lldb::ePathTypeSupportExecutableDir,
-                               expand_tool_spec)) {
+    FileSpec expand_tool_spec = HostInfo::GetSupportExeDir();
+    if (!expand_tool_spec) {
       error.SetErrorString("could not find support executable directory for "
                            "the lldb-argdumper tool");
       return error;
@@ -209,7 +206,7 @@ Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
     std::string output;
     std::string command = expand_command.GetString();
     RunShellCommand(command.c_str(), launch_info.GetWorkingDirectory(), &status,
-                    nullptr, &output, 10);
+                    nullptr, &output, std::chrono::seconds(10));
 
     if (status != 0) {
       error.SetErrorStringWithFormat("lldb-argdumper exited with error %d",
@@ -258,13 +255,12 @@ Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
   return error;
 }
 
-size_t Host::GetEnvironment(StringList &env) {
+Environment Host::GetEnvironment() {
+  Environment env;
   // The environment block on Windows is a contiguous buffer of NULL terminated
-  // strings,
-  // where the end of the environment block is indicated by two consecutive
-  // NULLs.
+  // strings, where the end of the environment block is indicated by two
+  // consecutive NULLs.
   LPWCH environment_block = ::GetEnvironmentStringsW();
-  env.Clear();
   while (*environment_block != L'\0') {
     std::string current_var;
     auto current_var_size = wcslen(environment_block) + 1;
@@ -273,9 +269,9 @@ size_t Host::GetEnvironment(StringList &env) {
       continue;
     }
     if (current_var[0] != '=')
-      env.AppendString(current_var);
+      env.insert(current_var);
 
     environment_block += current_var_size;
   }
-  return env.GetSize();
+  return env;
 }
diff --git a/source/Host/windows/HostInfoWindows.cpp b/source/Host/windows/HostInfoWindows.cpp
index 53a24ad1893ec..bd3f74f2e2f38 100644
--- a/source/Host/windows/HostInfoWindows.cpp
+++ b/source/Host/windows/HostInfoWindows.cpp
@@ -42,39 +42,33 @@ size_t HostInfoWindows::GetPageSize() {
   return systemInfo.dwPageSize;
 }
 
-bool HostInfoWindows::GetOSVersion(uint32_t &major, uint32_t &minor,
-                                   uint32_t &update) {
+llvm::VersionTuple HostInfoWindows::GetOSVersion() {
   OSVERSIONINFOEX info;
 
   ZeroMemory(&info, sizeof(OSVERSIONINFOEX));
   info.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
 #pragma warning(push)
 #pragma warning(disable : 4996)
-  // Starting with Microsoft SDK for Windows 8.1, this function is deprecated in
-  // favor of the
-  // new Windows Version Helper APIs.  Since we don't specify a minimum SDK
-  // version, it's easier
-  // to simply disable the warning rather than try to support both APIs.
-  if (GetVersionEx((LPOSVERSIONINFO)&info) == 0) {
-    return false;
-  }
+  // Starting with Microsoft SDK for Windows 8.1, this function is deprecated
+  // in favor of the new Windows Version Helper APIs.  Since we don't specify a
+  // minimum SDK version, it's easier to simply disable the warning rather than
+  // try to support both APIs.
+  if (GetVersionEx((LPOSVERSIONINFO)&info) == 0)
+    return llvm::VersionTuple();
 #pragma warning(pop)
 
-  major = info.dwMajorVersion;
-  minor = info.dwMinorVersion;
-  update = info.wServicePackMajor;
-
-  return true;
+  return llvm::VersionTuple(info.dwMajorVersion, info.dwMinorVersion,
+                            info.wServicePackMajor);
 }
 
 bool HostInfoWindows::GetOSBuildString(std::string &s) {
   s.clear();
-  uint32_t major, minor, update;
-  if (!GetOSVersion(major, minor, update))
+  llvm::VersionTuple version = GetOSVersion();
+  if (version.empty())
     return false;
 
   llvm::raw_string_ostream stream(s);
-  stream << "Windows NT " << major << "." << minor << "." << update;
+  stream << "Windows NT " << version.getAsString();
   return true;
 }
 
@@ -98,27 +92,20 @@ FileSpec HostInfoWindows::GetProgramFileSpec() {
     ::GetModuleFileNameW(NULL, buffer.data(), buffer.size());
     std::string path;
     llvm::convertWideToUTF8(buffer.data(), path);
-    m_program_filespec.SetFile(path, false);
+    m_program_filespec.SetFile(path, false, FileSpec::Style::native);
   });
   return m_program_filespec;
 }
 
 FileSpec HostInfoWindows::GetDefaultShell() {
+  // Try to retrieve ComSpec from the environment. On the rare occasion
+  // that it fails, try a well-known path for ComSpec instead.
+
   std::string shell;
-  GetEnvironmentVar("ComSpec", shell);
-  return FileSpec(shell, false);
-}
+  if (GetEnvironmentVar("ComSpec", shell))
+    return FileSpec(shell, false);
 
-bool HostInfoWindows::ComputePythonDirectory(FileSpec &file_spec) {
-  FileSpec lldb_file_spec;
-  if (!GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
-    return false;
-  llvm::SmallString<64> path(lldb_file_spec.GetDirectory().AsCString());
-  llvm::sys::path::remove_filename(path);
-  llvm::sys::path::append(path, "lib", "site-packages");
-  std::replace(path.begin(), path.end(), '\\', '/');
-  file_spec.GetDirectory().SetString(path.c_str());
-  return true;
+  return FileSpec("C:\\Windows\\system32\\cmd.exe", false);
 }
 
 bool HostInfoWindows::GetEnvironmentVar(const std::string &var_name,
diff --git a/source/Host/windows/HostProcessWindows.cpp b/source/Host/windows/HostProcessWindows.cpp
index 49d42ce054223..ce75c14cdcf4e 100644
--- a/source/Host/windows/HostProcessWindows.cpp
+++ b/source/Host/windows/HostProcessWindows.cpp
@@ -57,7 +57,7 @@ Status HostProcessWindows::GetMainModule(FileSpec &file_spec) const {
   if (::GetProcessImageFileNameW(m_process, wpath.data(), wpath.size())) {
     std::string path;
     if (llvm::convertWideToUTF8(wpath.data(), path))
-      file_spec.SetFile(path, false);
+      file_spec.SetFile(path, false, FileSpec::Style::native);
     else
       error.SetErrorString("Error converting path to UTF-8");
   } else
@@ -88,8 +88,8 @@ HostThread HostProcessWindows::StartMonitoring(
   info->callback = callback;
 
   // Since the life of this HostProcessWindows instance and the life of the
-  // process may be different, duplicate the handle so that
-  // the monitor thread can have ownership over its own copy of the handle.
+  // process may be different, duplicate the handle so that the monitor thread
+  // can have ownership over its own copy of the handle.
   HostThread result;
   if (::DuplicateHandle(GetCurrentProcess(), m_process, GetCurrentProcess(),
                         &info->process_handle, 0, FALSE, DUPLICATE_SAME_ACCESS))
diff --git a/source/Host/windows/PipeWindows.cpp b/source/Host/windows/PipeWindows.cpp
index e8f4753d11e2c..1951c9ca193ad 100644
--- a/source/Host/windows/PipeWindows.cpp
+++ b/source/Host/windows/PipeWindows.cpp
@@ -40,11 +40,9 @@ PipeWindows::PipeWindows() {
 PipeWindows::~PipeWindows() { Close(); }
 
 Status PipeWindows::CreateNew(bool child_process_inherit) {
-  // Even for anonymous pipes, we open a named pipe.  This is because you cannot
-  // get
-  // overlapped i/o on Windows without using a named pipe.  So we synthesize a
-  // unique
-  // name.
+  // Even for anonymous pipes, we open a named pipe.  This is because you
+  // cannot get overlapped i/o on Windows without using a named pipe.  So we
+  // synthesize a unique name.
   uint32_t serial = g_pipe_serial.fetch_add(1);
   std::string pipe_name;
   llvm::raw_string_ostream pipe_name_stream(pipe_name);
@@ -65,8 +63,8 @@ Status PipeWindows::CreateNew(llvm::StringRef name,
   std::string pipe_path = "\\\\.\\Pipe\\";
   pipe_path.append(name);
 
-  // Always open for overlapped i/o.  We implement blocking manually in Read and
-  // Write.
+  // Always open for overlapped i/o.  We implement blocking manually in Read
+  // and Write.
   DWORD read_mode = FILE_FLAG_OVERLAPPED;
   m_read = ::CreateNamedPipeA(
       pipe_path.c_str(), PIPE_ACCESS_INBOUND | read_mode,
@@ -250,12 +248,10 @@ Status PipeWindows::ReadWithTimeout(void *buf, size_t size,
   DWORD wait_result = ::WaitForSingleObject(m_read_overlapped.hEvent, timeout);
   if (wait_result != WAIT_OBJECT_0) {
     // The operation probably failed.  However, if it timed out, we need to
-    // cancel the I/O.
-    // Between the time we returned from WaitForSingleObject and the time we
-    // call CancelIoEx,
-    // the operation may complete.  If that hapens, CancelIoEx will fail and
-    // return ERROR_NOT_FOUND.
-    // If that happens, the original operation should be considered to have been
+    // cancel the I/O. Between the time we returned from WaitForSingleObject
+    // and the time we call CancelIoEx, the operation may complete.  If that
+    // hapens, CancelIoEx will fail and return ERROR_NOT_FOUND. If that
+    // happens, the original operation should be considered to have been
     // successful.
     bool failed = true;
     DWORD failure_error = ::GetLastError();
@@ -268,9 +264,8 @@ Status PipeWindows::ReadWithTimeout(void *buf, size_t size,
       return Status(failure_error, eErrorTypeWin32);
   }
 
-  // Now we call GetOverlappedResult setting bWait to false, since we've already
-  // waited
-  // as long as we're willing to.
+  // Now we call GetOverlappedResult setting bWait to false, since we've
+  // already waited as long as we're willing to.
   if (!GetOverlappedResult(m_read, &m_read_overlapped, &sys_bytes_read, FALSE))
     return Status(::GetLastError(), eErrorTypeWin32);
 
diff --git a/source/Host/windows/ProcessLauncherWindows.cpp b/source/Host/windows/ProcessLauncherWindows.cpp
index 56089742f0932..553dd9d286da8 100644
--- a/source/Host/windows/ProcessLauncherWindows.cpp
+++ b/source/Host/windows/ProcessLauncherWindows.cpp
@@ -21,14 +21,15 @@ using namespace lldb;
 using namespace lldb_private;
 
 namespace {
-void CreateEnvironmentBuffer(const Args &env, std::vector<char> &buffer) {
-  if (env.GetArgumentCount() == 0)
+void CreateEnvironmentBuffer(const Environment &env,
+                             std::vector<char> &buffer) {
+  if (env.size() == 0)
     return;
 
   // Environment buffer is a null terminated list of null terminated strings
-  for (auto &entry : env.entries()) {
+  for (const auto &KV : env) {
     std::wstring warg;
-    if (llvm::ConvertUTF8toWide(entry.ref, warg)) {
+    if (llvm::ConvertUTF8toWide(Environment::compose(KV), warg)) {
       buffer.insert(buffer.end(), (char *)warg.c_str(),
                     (char *)(warg.c_str() + warg.size() + 1));
     }
@@ -75,9 +76,8 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
   if (launch_info.GetFlags().Test(eLaunchFlagDebug))
     flags |= DEBUG_ONLY_THIS_PROCESS;
 
-  auto &env = const_cast<Args &>(launch_info.GetEnvironmentEntries());
   LPVOID env_block = nullptr;
-  ::CreateEnvironmentBuffer(env, environment);
+  ::CreateEnvironmentBuffer(launch_info.GetEnvironment(), environment);
   if (!environment.empty())
     env_block = environment.data();
 
@@ -96,6 +96,12 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
       wexecutable.c_str(), &wcommandLine[0], NULL, NULL, TRUE, flags, env_block,
       wworkingDirectory.size() == 0 ? NULL : wworkingDirectory.c_str(),
       &startupinfo, &pi);
+
+  if (!result) {
+    // Call GetLastError before we make any other system calls.
+    error.SetError(::GetLastError(), eErrorTypeWin32);
+  }
+
   if (result) {
     // Do not call CloseHandle on pi.hProcess, since we want to pass that back
     // through the HostProcess.
@@ -110,7 +116,8 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
     ::CloseHandle(stderr_handle);
 
   if (!result)
-    error.SetError(::GetLastError(), eErrorTypeWin32);
+    return HostProcess();
+
   return HostProcess(pi.hProcess);
 }