[Tooling] Clear the PreambleSrcLocCache when preamble is discarded during reparsing

This ensures that diagnostics are not remapped to incorrect preamble locations after
the second reparse with a remapped header file occurs.

rdar://37502480

llvm-svn: 327322

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 473da22e9b4..d73bc284acb 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1259,6 +1259,7 @@ ASTUnit::getMainBufferWithPrecompiledPreamble(
       Preamble.reset();
       PreambleDiagnostics.clear();
       TopLevelDeclsInPreamble.clear();
+      PreambleSrcLocCache.clear();
       PreambleRebuildCounter = 1;
     }
   }