[lldb][NFCI] Change return type of GetProcessPluginName

[bulbazord]

Summary

Instead of just returning a raw const char *, I think llvm::StringRef
would make more sense. Most of the time that we use the return value of
GetProcessPluginName we're passing it to CreateProcess which takes a
StringRef anyway.

[JDevlieghere]

LGTM

lldb/include/lldb/Host/ProcessLaunchInfo.h

public:
   Flags &GetFlags() { return m_flags; }
 
   const Flags &GetFlags() const { return m_flags; }
 
   const FileSpec &GetWorkingDirectory() const;
 
   void SetWorkingDirectory(const FileSpec &working_dir);
 
-  const char *GetProcessPluginName() const;
+  llvm::StringRef GetProcessPluginName() const;
 
   void SetProcessPluginName(llvm::StringRef plugin);
 
   const FileSpec &GetShell() const;
 
   void SetShell(const FileSpec &shell);
 
   uint32_t GetResumeCount() const { return m_resume_count; }

lldb/include/lldb/Target/Process.h

public:
   bool GetContinueOnceAttached() const { return m_continue_once_attached; }
 
   void SetContinueOnceAttached(bool b) { m_continue_once_attached = b; }
 
   uint32_t GetResumeCount() const { return m_resume_count; }
 
   void SetResumeCount(uint32_t c) { m_resume_count = c; }
 
-  const char *GetProcessPluginName() const {
-    return (m_plugin_name.empty() ? nullptr : m_plugin_name.c_str());
+  llvm::StringRef GetProcessPluginName() const {
+    return llvm::StringRef(m_plugin_name);
   }
 
   void SetProcessPluginName(llvm::StringRef plugin) {
     m_plugin_name = std::string(plugin);
   }
 
   void Clear() {
     ProcessInstanceInfo::Clear();

lldb/source/Host/common/ProcessLaunchInfo.cpp

 const FileSpec &ProcessLaunchInfo::GetWorkingDirectory() const {
   return m_working_dir;
 }
 
 void ProcessLaunchInfo::SetWorkingDirectory(const FileSpec &working_dir) {
   m_working_dir = working_dir;
 }
 
-const char *ProcessLaunchInfo::GetProcessPluginName() const {
-  return (m_plugin_name.empty() ? nullptr : m_plugin_name.c_str());
+llvm::StringRef ProcessLaunchInfo::GetProcessPluginName() const {
+  return llvm::StringRef(m_plugin_name);
 }
 
 void ProcessLaunchInfo::SetProcessPluginName(llvm::StringRef plugin) {
   m_plugin_name = std::string(plugin);
 }
 
 const FileSpec &ProcessLaunchInfo::GetShell() const { return m_shell; }
 

lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp

if (target == nullptr) {
     error = debugger.GetTargetList().CreateTarget(
         debugger, "", "", eLoadDependentsNo, nullptr, new_target_sp);
     target = new_target_sp.get();
   }
 
   if (!target || error.Fail())
     return process_sp;
 
-  const char *plugin_name = attach_info.GetProcessPluginName();
-  process_sp = target->CreateProcess(
-      attach_info.GetListenerForProcess(debugger), plugin_name, nullptr, false);
+  process_sp =
+      target->CreateProcess(attach_info.GetListenerForProcess(debugger),
+                            attach_info.GetProcessPluginName(), nullptr, false);
 
   process_sp->HijackProcessEvents(attach_info.GetHijackListener());
   if (process_sp)
     error = process_sp->Attach(attach_info);
 
   return process_sp;
 }
 

lldb/source/Target/Target.cpp

LLDB_LOGF(log,
               "Target::%s the platform doesn't know how to debug a "
               "process, getting a process plugin to do this for us.",
               __FUNCTION__);
 
     if (state == eStateConnected) {
       assert(m_process_sp);
     } else {
       // Use a Process plugin to construct the process.
-      const char *plugin_name = launch_info.GetProcessPluginName();
-      CreateProcess(launch_info.GetListener(), plugin_name, nullptr, false);
+      CreateProcess(launch_info.GetListener(),
+                    launch_info.GetProcessPluginName(), nullptr, false);
     }
 
     // Since we didn't have a platform launch the process, launch it here.
     if (m_process_sp) {
       m_process_sp->HijackProcessEvents(launch_info.GetHijackListener());
       m_process_sp->SetShadowListener(launch_info.GetShadowListener());
       error = m_process_sp->Launch(launch_info);
     }
Status Target::Attach(ProcessAttachInfo &attach_info, Stream *stream) {
   Status error;
   if (state != eStateConnected && platform_sp != nullptr &&
       platform_sp->CanDebugProcess() && !attach_info.IsScriptedProcess()) {
     SetPlatform(platform_sp);
     process_sp = platform_sp->Attach(attach_info, GetDebugger(), this, error);
   } else {
     if (state != eStateConnected) {
       SaveScriptedLaunchInfo(attach_info);
-      const char *plugin_name = attach_info.GetProcessPluginName();
+      llvm::StringRef plugin_name = attach_info.GetProcessPluginName();
       process_sp =
           CreateProcess(attach_info.GetListenerForProcess(GetDebugger()),
                         plugin_name, nullptr, false);
-      if (process_sp == nullptr) {
-        error.SetErrorStringWithFormat(
-            "failed to create process using plugin %s",
-            (plugin_name) ? plugin_name : "null");
+      if (!process_sp) {
+        error.SetErrorStringWithFormatv(
+            "failed to create process using plugin '{0}'",
+            plugin_name.empty() ? "<empty>" : plugin_name);
         return error;
       }
     }
     if (hijack_listener_sp)
       process_sp->HijackProcessEvents(hijack_listener_sp);
     error = process_sp->Attach(attach_info);
   }