Use makeAbsolute()

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@98472 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CacheTokens.cpp b/lib/Frontend/CacheTokens.cpp
index 21db55b..b845178 100644
--- a/lib/Frontend/CacheTokens.cpp
+++ b/lib/Frontend/CacheTokens.cpp
@@ -534,13 +534,8 @@
   llvm::sys::Path MainFilePath(MainFile->getName());
   std::string MainFileName;
 
-  if (!MainFilePath.isAbsolute()) {
-    llvm::sys::Path P = llvm::sys::Path::GetCurrentDirectory();
-    P.appendComponent(MainFilePath.str());
-    MainFileName = P.str();
-  } else {
-    MainFileName = MainFilePath.str();
-  }
+  MainFilePath.makeAbsolute();
+  MainFileName = MainFilePath.str();
 
   // Create the PTHWriter.
   PTHWriter PW(*OS, PP);