[lldb/Platform] Return a std::string from GetSDKPath

Nothing guarantees that the objects in the StringMap remains at the same
address when the StringMap grows. Therefore we shouldn't return a
reference into the StringMap but return a copy of the string instead.

Author: JDevlieghere

lldb/include/lldb/Target/Platform.h

@@ -435,7 +435,7 @@ class Platform : public PluginInterface {
     return lldb_private::ConstString();
   }
 
-  virtual llvm::StringRef GetSDKPath(lldb_private::XcodeSDK sdk) {
+  virtual std::string GetSDKPath(lldb_private::XcodeSDK sdk) {
     return {};
   }
 

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

@@ -1761,11 +1761,11 @@ PlatformDarwin::FindXcodeContentsDirectoryInPath(llvm::StringRef path) {
   return {};
 }
 
-llvm::StringRef PlatformDarwin::GetSDKPath(XcodeSDK sdk) {
+std::string PlatformDarwin::GetSDKPath(XcodeSDK sdk) {
   std::string &path = m_sdk_path[sdk.GetString()];
-  if (path.empty())
-    path = HostInfo::GetXcodeSDK(sdk);
-  return path;
+  if (!path.empty())
+    return path;
+  return HostInfo::GetXcodeSDK(sdk);
 }
 
 FileSpec PlatformDarwin::GetXcodeContentsDirectory() {

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

@@ -89,7 +89,7 @@ class PlatformDarwin : public PlatformPOSIX {
   llvm::Expected<lldb_private::StructuredData::DictionarySP>
   FetchExtendedCrashInformation(lldb_private::Process &process) override;
 
-  llvm::StringRef GetSDKPath(lldb_private::XcodeSDK sdk) override;
+  std::string GetSDKPath(lldb_private::XcodeSDK sdk) override;
 
   static lldb_private::FileSpec GetXcodeContentsDirectory();
   static lldb_private::FileSpec GetXcodeDeveloperDirectory();