[libclang] When getting a source location from a file:line:col triplet
check whether the requested location points inside the precompiled preamble,
in which case the returned source location will be a "loaded" one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140060 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 92798c8..924864c 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -539,11 +539,8 @@
                                                FileManager &FileMgr,
                                                SourceManager &SourceMgr,
                                                const FrontendOptions &Opts) {
-  // Figure out where to get and map in the main file, unless it's already
-  // been created (e.g., by a precompiled preamble).
-  if (!SourceMgr.getMainFileID().isInvalid()) {
-    // Do nothing: the main file has already been set.
-  } else if (InputFile != "-") {
+  // Figure out where to get and map in the main file.
+  if (InputFile != "-") {
     const FileEntry *File = FileMgr.getFile(InputFile);
     if (!File) {
       Diags.Report(diag::err_fe_error_reading) << InputFile;