[lldb/Commands] Fix heap-use-after-free error in CommandObjectProcess

This patch should fix the use-after-free error that was brought up by
the LLDB ASAN Green Dragon bot.

This is caused because the `StringRef` object was acquired too early
before being use and by the underlying memory was modified which caused
it to point to null memory.

Fetching back the string reference close to its usage location should
fix the issue.

Signed-off-by: Med Ismail Bennani <[email protected]>

Author: medismailben

lldb/source/Commands/CommandObjectProcess.cpp

@@ -170,8 +170,6 @@ class CommandObjectProcessLaunch : public CommandObjectProcessLaunchOrAttach {
     if (!StopProcessIfNecessary(m_exe_ctx.GetProcessPtr(), state, result))
       return false;
 
-    llvm::StringRef target_settings_argv0 = target->GetArg0();
-
     // Determine whether we will disable ASLR or leave it in the default state
     // (i.e. enabled if the platform supports it). First check if the process
     // launch options explicitly turn on/off
@@ -216,6 +214,8 @@ class CommandObjectProcessLaunch : public CommandObjectProcessLaunchOrAttach {
     m_options.launch_info.GetEnvironment().insert(target_env.begin(),
                                                   target_env.end());
 
+    llvm::StringRef target_settings_argv0 = target->GetArg0();
+
     if (!target_settings_argv0.empty()) {
       m_options.launch_info.GetArguments().AppendArgument(
           target_settings_argv0);