Driver: Fix a possible use after free.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108659 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index f423d4e..6e6dab1 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1489,7 +1489,7 @@
 
   Args.AddAllArgs(CmdArgs, options::OPT_undef);
 
-  std::string Exec = getToolChain().getDriver().getClangProgramPath();
+  const char *Exec = getToolChain().getDriver().getClangProgramPath();
 
   // Optionally embed the -cc1 level arguments into the debug info, for build
   // analysis.
@@ -1509,7 +1509,7 @@
     CmdArgs.push_back(Args.MakeArgString(Flags.str()));
   }
 
-  Dest.addCommand(new Command(JA, *this, Exec.c_str(), CmdArgs));
+  Dest.addCommand(new Command(JA, *this, Exec, CmdArgs));
 
   // Explicitly warn that these options are unsupported, even though
   // we are allowing compilation to continue.
@@ -1588,8 +1588,8 @@
     CmdArgs.push_back(Input.getFilename());
   }
 
-  std::string Exec = getToolChain().getDriver().getClangProgramPath();
-  Dest.addCommand(new Command(JA, *this, Exec.c_str(), CmdArgs));
+  const char *Exec = getToolChain().getDriver().getClangProgramPath();
+  Dest.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
 void gcc::Common::ConstructJob(Compilation &C, const JobAction &JA,