Handle user files as volatile in tooling on windows

Prevent locking user files when running clang tools by marking them as
volatile. Non volatile files will be mapped into memory and a handle is
kept to track file changes. This handle can prevent other processes to
access or remove the file.

Fixes: QTCREATORBUG-24911
Change-Id: I517e9982972a9e5e20df60c603675a9d370004c6
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

3 files changed, 10 insertions, 4 deletions

diff --git a/clang/include/clang/Frontend/CompilerInstance.h b/clang/include/clang/Frontend/CompilerInstance.h
index f132c961c8a2..f9a5d6ce02f3 100644
--- a/clang/include/clang/Frontend/CompilerInstance.h
+++ b/clang/include/clang/Frontend/CompilerInstance.h
@@ -640,7 +640,7 @@ public:
   createFileManager(IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
 
   /// Create the source manager and replace any existing one with it.
-  void createSourceManager(FileManager &FileMgr);
+  void createSourceManager(FileManager &FileMgr, bool UserFilesAreVolatile = false);
 
   /// Create the preprocessor, using the invocation, file, and source managers,
   /// and replace any existing one with it.
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index ac9f8f8ed51c..0cf4de8f23f8 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -389,8 +389,8 @@ FileManager *CompilerInstance::createFileManager(
 
 // Source Manager
 
-void CompilerInstance::createSourceManager(FileManager &FileMgr) {
-  SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
+void CompilerInstance::createSourceManager(FileManager &FileMgr, bool UserFilesAreVolatile) {
+  SourceMgr = new SourceManager(getDiagnostics(), FileMgr, UserFilesAreVolatile);
 }
 
 // Initialize the remapping of files to alternative contents, e.g.,
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index 8966c12ef7c1..4a65a6f410a2 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -429,7 +429,13 @@ bool FrontendActionFactory::runInvocation(
   if (!Compiler.hasDiagnostics())
     return false;
 
-  Compiler.createSourceManager(*Files);
+#ifdef _WIN32
+  constexpr static bool UserFilesAreVolatile = true;
+#else
+  constexpr static bool UserFilesAreVolatile = false;
+#endif
+
+  Compiler.createSourceManager(*Files, UserFilesAreVolatile);
 
   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);