1 files changed, 12 insertions, 2 deletions
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 9cb26f8..187e2b7 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1022,9 +1022,19 @@ static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
     case llvm::LockFileManager::LFS_Shared:
       // Someone else is responsible for building the module. Wait for them to
       // finish.
-      if (Locked.waitForUnlock() == llvm::LockFileManager::Res_OwnerDied)
+      switch (Locked.waitForUnlock()) {
+      case llvm::LockFileManager::Res_Success:
+        ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
+        break;
+      case llvm::LockFileManager::Res_OwnerDied:
         continue; // try again to get the lock.
-      ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
+      case llvm::LockFileManager::Res_Timeout:
+        Diags.Report(ModuleNameLoc, diag::err_module_lock_timeout)
+            << Module->Name;
+        // Clear the lock file so that future invokations can make progress.
+        Locked.unsafeRemoveLockFile();
+        return false;
+      }
       break;
     }