[PCH] When writing out the list of input files, avoid emitting duplicate

entries of the same file.

This can happen because the file was "included" multiple times and is
referenced by multiple SLocEntries.

llvm-svn: 169829

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index ff98d9beb05..ed0a272faa0 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1235,9 +1235,14 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
     if (!Cache->OrigEntry)
       continue;
 
+    uint32_t &InputFileID = InputFileIDs[Cache->OrigEntry];
+    if (InputFileID != 0)
+      continue; // already recorded this file.
+
     // Record this entry's offset.
     InputFileOffsets.push_back(Stream.GetCurrentBitNo());
-    InputFileIDs[Cache->OrigEntry] = InputFileOffsets.size();
+
+    InputFileID = InputFileOffsets.size();
 
     Record.clear();
     Record.push_back(INPUT_FILE);