Fix a deadlock issue that would happen when loading an AppleTV or watchOS binary.

This was a regression that was caused by svn revision 269877:

commit 1ded4a2a25d60dd2c81bd432bcf63b6ded58e5d6
Author: Saleem Abdulrasool <compnerd@compnerd.org>
Date:   Wed May 18 01:59:10 2016 +0000

    remove use of Mutex in favour of std::{,recursive_}mutex
    
    This is a pretty straightforward first pass over removing a number of uses of
    Mutex in favor of std::mutex or std::recursive_mutex. The problem is that there
    are interfaces which take Mutex::Locker & to lock internal locks. This patch
    cleans up most of the easy cases. The only non-trivial change is in
    CommandObjectTarget.cpp where a Mutex::Locker was split into two.
    
    git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@269877 91177308-0d34-0410-b5e6-96231b3b80d8

This change actually changed the Platform::m_mutex to be non-recursive which caused the regression.

<rdar://problem/29094384>

llvm-svn: 286908

lldb/source/Plugins/Platform/MacOSX/PlatformAppleWatchSimulator.cpp

@@ -263,7 +263,7 @@ EnumerateDirectoryCallback(void *baton, FileSpec::FileType file_type,
 }
 
 const char *PlatformAppleWatchSimulator::GetSDKDirectoryAsCString() {
-  std::lock_guard<std::mutex> guard(m_mutex);
+  std::lock_guard<std::mutex> guard(m_sdk_dir_mutex);
   if (m_sdk_directory.empty()) {
     const char *developer_dir = GetDeveloperDirectory();
     if (developer_dir) {

lldb/source/Plugins/Platform/MacOSX/PlatformAppleWatchSimulator.h

@@ -86,6 +86,7 @@ public:
   }
 
 protected:
+  std::mutex m_sdk_dir_mutex;
   std::string m_sdk_directory;
   std::string m_build_update;
 

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleTV.cpp

@@ -258,6 +258,7 @@ PlatformRemoteAppleTV::GetContainedFilesIntoVectorOfStringsCallback(
 
 bool PlatformRemoteAppleTV::UpdateSDKDirectoryInfosIfNeeded() {
   Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+  std::lock_guard<std::mutex> guard(m_sdk_dir_mutex);
   if (m_sdk_directory_infos.empty()) {
     const char *device_support_dir = GetDeviceSupportDirectory();
     if (log) {

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleTV.h

@@ -96,6 +96,7 @@ protected:
     bool user_cached;
   };
   typedef std::vector<SDKDirectoryInfo> SDKDirectoryInfoCollection;
+  std::mutex m_sdk_dir_mutex;
   SDKDirectoryInfoCollection m_sdk_directory_infos;
   std::string m_device_support_directory;
   std::string m_device_support_directory_for_os_version;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.cpp

@@ -268,6 +268,7 @@ PlatformRemoteAppleWatch::GetContainedFilesIntoVectorOfStringsCallback(
 
 bool PlatformRemoteAppleWatch::UpdateSDKDirectoryInfosIfNeeded() {
   Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+  std::lock_guard<std::mutex> guard(m_sdk_dir_mutex);
   if (m_sdk_directory_infos.empty()) {
     const char *device_support_dir = GetDeviceSupportDirectory();
     if (log) {

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.h

@@ -98,6 +98,7 @@ protected:
     bool user_cached;
   };
   typedef std::vector<SDKDirectoryInfo> SDKDirectoryInfoCollection;
+  std::mutex m_sdk_dir_mutex;
   SDKDirectoryInfoCollection m_sdk_directory_infos;
   std::string m_device_support_directory;
   std::string m_device_support_directory_for_os_version;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteiOS.cpp

@@ -263,6 +263,7 @@ PlatformRemoteiOS::GetContainedFilesIntoVectorOfStringsCallback(
 
 bool PlatformRemoteiOS::UpdateSDKDirectoryInfosIfNeeded() {
   Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+  std::lock_guard<std::mutex> guard(m_sdk_dir_mutex);
   if (m_sdk_directory_infos.empty()) {
     // A --sysroot option was supplied - add it to our list of SDKs to check
     if (m_sdk_sysroot) {

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteiOS.h

@@ -94,6 +94,7 @@ protected:
 
   typedef std::vector<SDKDirectoryInfo> SDKDirectoryInfoCollection;
 
+  std::mutex m_sdk_dir_mutex;
   SDKDirectoryInfoCollection m_sdk_directory_infos;
   std::string m_device_support_directory;
   std::string m_device_support_directory_for_os_version;