1 files changed, 22 insertions, 0 deletions
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 7ce1aad36d12a..3efe914daaeef 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -47,6 +47,7 @@ class ExternalPreprocessorSource;
 class FileManager;
 class FileEntry;
 class HeaderSearch;
+class MemoryBufferCache;
 class PragmaNamespace;
 class PragmaHandler;
 class CommentHandler;
@@ -102,6 +103,7 @@ class Preprocessor {
   const TargetInfo  *AuxTarget;
   FileManager       &FileMgr;
   SourceManager     &SourceMgr;
+  MemoryBufferCache &PCMCache;
   std::unique_ptr<ScratchBuffer> ScratchBuf;
   HeaderSearch      &HeaderInfo;
   ModuleLoader      &TheModuleLoader;
@@ -652,6 +654,7 @@ class Preprocessor {
 public:
   Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
                DiagnosticsEngine &diags, LangOptions &opts, SourceManager &SM,
+               MemoryBufferCache &PCMCache,
                HeaderSearch &Headers, ModuleLoader &TheModuleLoader,
                IdentifierInfoLookup *IILookup = nullptr,
                bool OwnsHeaderSearch = false,
@@ -691,6 +694,7 @@ public:
   const TargetInfo *getAuxTargetInfo() const { return AuxTarget; }
   FileManager &getFileManager() const { return FileMgr; }
   SourceManager &getSourceManager() const { return SourceMgr; }
+  MemoryBufferCache &getPCMCache() const { return PCMCache; }
   HeaderSearch &getHeaderSearchInfo() const { return HeaderInfo; }
 
   IdentifierTable &getIdentifierTable() { return Identifiers; }
@@ -1077,6 +1081,24 @@ public:
   /// \brief Disable the last EnableBacktrackAtThisPos call.
   void CommitBacktrackedTokens();
 
+  struct CachedTokensRange {
+    CachedTokensTy::size_type Begin, End;
+  };
+
+private:
+  /// \brief A range of cached tokens that should be erased after lexing
+  /// when backtracking requires the erasure of such cached tokens.
+  Optional<CachedTokensRange> CachedTokenRangeToErase;
+
+public:
+  /// \brief Returns the range of cached tokens that were lexed since
+  /// EnableBacktrackAtThisPos() was previously called.
+  CachedTokensRange LastCachedTokenRange();
+
+  /// \brief Erase the range of cached tokens that were lexed since
+  /// EnableBacktrackAtThisPos() was previously called.
+  void EraseCachedTokens(CachedTokensRange TokenRange);
+
   /// \brief Make Preprocessor re-lex the tokens that were lexed since
   /// EnableBacktrackAtThisPos() was previously called.
   void Backtrack();