Add SourceManagerForFile helper which sets up SourceManager and dependencies for a single file with code snippet

Summary: This can be used to create a virtual environment (incl. VFS, source manager) for code snippets.

Reviewers: sammccall, klimek

Reviewed By: sammccall

Subscribers: klimek, mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D46176

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@331923 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 1 deletions

diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index 25acdd2600..33e63d9d40 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -35,6 +35,7 @@
 #ifndef LLVM_CLANG_BASIC_SOURCEMANAGER_H
 #define LLVM_CLANG_BASIC_SOURCEMANAGER_H
 
+#include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -60,7 +61,6 @@ namespace clang {
 
 class ASTReader;
 class ASTWriter;
-class DiagnosticsEngine;
 class LineTableInfo;
 class SourceManager;
 
@@ -1815,6 +1815,28 @@ public:
   }
 };
 
+/// SourceManager and necessary depdencies (e.g. VFS, FileManager) for a single
+/// in-memorty file.
+class SourceManagerForFile {
+public:
+  /// Creates SourceManager and necessary depdencies (e.g. VFS, FileManager).
+  /// The main file in the SourceManager will be \p FileName with \p Content.
+  SourceManagerForFile(StringRef FileName, StringRef Content);
+
+  SourceManager &get() {
+    assert(SourceMgr);
+    return *SourceMgr;
+  }
+
+private:
+  // The order of these fields are important - they should be in the same order
+  // as they are created in `createSourceManagerForFile` so that they can be
+  // deleted in the reverse order as they are created.
+  std::unique_ptr<FileManager> FileMgr;
+  std::unique_ptr<DiagnosticsEngine> Diagnostics;
+  std::unique_ptr<SourceManager> SourceMgr;
+};
+
 } // namespace clang
 
 #endif // LLVM_CLANG_BASIC_SOURCEMANAGER_H