[modules] When emitting line tables, only emit filenames that are actually referenced by the entries that we emit.

llvm-svn: 246534

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 1d692c8d7f4..f4044624d07 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -1058,11 +1058,12 @@ bool ASTReader::ParseLineTable(ModuleFile &F,
 
   // Parse the file names
   std::map<int, int> FileIDs;
-  for (int I = 0, N = Record[Idx++]; I != N; ++I) {
+  for (unsigned I = 0; Record[Idx]; ++I) {
     // Extract the file name
     auto Filename = ReadPath(F, Record, Idx);
     FileIDs[I] = LineTable.getLineTableFilenameID(Filename);
   }
+  ++Idx;
 
   // Parse the line entries
   std::vector<LineEntry> Entries;
@@ -1074,7 +1075,7 @@ bool ASTReader::ParseLineTable(ModuleFile &F,
 
     // Extract the line entries
     unsigned NumEntries = Record[Idx++];
-    assert(NumEntries && "Numentries is 00000");
+    assert(NumEntries && "no line entries for file ID");
     Entries.clear();
     Entries.reserve(NumEntries);
     for (unsigned I = 0; I != NumEntries; ++I) {