Fixes a segfault in Tooling when using pch's:

Clear the FileManager's stat cache in between running
translation units, as the stat cache loaded from a pch
is only valid for one compiler invocation.

llvm-svn: 161047

clang/include/clang/Basic/FileManager.h

@@ -186,6 +186,9 @@ public:
   /// \brief Removes the specified FileSystemStatCache object from the manager.
   void removeStatCache(FileSystemStatCache *statCache);
 
+  /// \brief Removes all FileSystemStatCache objects from the manager.
+  void clearStatCaches();
+
   /// \brief Lookup, cache, and verify the specified directory (real or
   /// virtual).
   ///

clang/lib/Basic/FileManager.cpp

@@ -223,6 +223,10 @@ void FileManager::removeStatCache(FileSystemStatCache *statCache) {
   PrevCache->setNextStatCache(statCache->getNextStatCache());
 }
 
+void FileManager::clearStatCaches() {
+  StatCache.reset(0);
+}
+
 /// \brief Retrieve the directory that the given file name resides in.
 /// Filename can point to either a real file or a virtual file.
 static const DirectoryEntry *getDirectoryFromFile(FileManager &FileMgr,

clang/lib/Tooling/Tooling.cpp

@@ -212,6 +212,7 @@ bool ToolInvocation::runInvocation(
   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
 
   Compiler.resetAndLeakFileManager();
+  Files->clearStatCaches();
   return Success;
 }
 

clang/test/Tooling/Inputs/lit.local.cfg

@@ -0,0 +1 @@
+config.suffixes = []

clang/test/Tooling/pch.cpp

@@ -0,0 +1,21 @@
+// This is a regression test for handling of stat caches within the tooling
+// infrastructure. This test reproduces the problem under valgrind:
+
+// First, create a pch that we can later load. Loading the pch will insert
+// a stat cache into the FileManager:
+// RUN: %clang -x c++-header %S/Inputs/pch.h -o %t1
+
+// Use the generated pch and enforce a subsequent stat miss by by using
+// the test file with an unrelated include as second translation unit:
+// Do not directly pipe into FileCheck, as that would hide errors from
+// valgrind due to pipefail not being set in lit.
+// RUN: clang-check "%S/Inputs/pch.cpp" "%s" -- -include-pch %t1 -I "%S" -c >%t2 2>&1
+// RUN: FileCheck %s < %t2
+
+#include "Inputs/pch-fail.h"
+
+// CHECK: Processing
+
+// FIXME: This is incompatible to -fms-compatibility.
+// XFAIL: win32
+