Index: include/clang/Lex/HeaderSearch.h =================================================================== --- include/clang/Lex/HeaderSearch.h (revision 144239) +++ include/clang/Lex/HeaderSearch.h (working copy) @@ -199,6 +199,15 @@ //LookupFileCache.clear(); } + /// AddSearchPath - Add an additional search path. + void AddSearchPath(const DirectoryLookup &dir, bool isAngled) { + std::vector::iterator it = SearchDirs.begin(); + SearchDirs.insert(isAngled ? it + SystemDirIdx : it + AngledDirIdx, dir); + if (!isAngled) + AngledDirIdx++; + SystemDirIdx++; + } + /// \brief Set the path to the module cache and the name of the module /// we're building void configureModules(StringRef CachePath, StringRef BuildingModule) { @@ -255,7 +264,8 @@ const FileEntry *CurFileEnt, SmallVectorImpl *SearchPath, SmallVectorImpl *RelativePath, - StringRef *SuggestedModule); + StringRef *SuggestedModule, + bool SkipCache = false); /// LookupSubframeworkHeader - Look up a subframework for the specified /// #include file. For example, if #include'ing from Index: include/clang/Lex/PPCallbacks.h =================================================================== --- include/clang/Lex/PPCallbacks.h (revision 144239) +++ include/clang/Lex/PPCallbacks.h (working copy) @@ -91,6 +91,9 @@ /// /// \param RelativePath The path relative to SearchPath, at which the include /// file was found. This is equal to FileName except for framework includes. + /// + /// \param RecoveryPath If File is null the client may recover from the + /// failure by supplying an additional search path in RecoveryPath. virtual void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName, @@ -98,7 +101,8 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath) { + StringRef RelativePath, + SmallVectorImpl &RecoveryPath) { } /// EndOfMainFile - This callback is invoked when the end of the main file is @@ -238,11 +242,12 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath) { + StringRef RelativePath, + SmallVectorImpl &RecoveryPath) { First->InclusionDirective(HashLoc, IncludeTok, FileName, IsAngled, File, - EndLoc, SearchPath, RelativePath); + EndLoc, SearchPath, RelativePath, RecoveryPath); Second->InclusionDirective(HashLoc, IncludeTok, FileName, IsAngled, File, - EndLoc, SearchPath, RelativePath); + EndLoc, SearchPath, RelativePath, RecoveryPath); } virtual void EndOfMainFile() { Index: include/clang/Lex/PreprocessingRecord.h =================================================================== --- include/clang/Lex/PreprocessingRecord.h (revision 144239) +++ include/clang/Lex/PreprocessingRecord.h (working copy) @@ -545,7 +545,8 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath); + StringRef RelativePath, + SmallVectorImpl &RecoveryPath); private: /// \brief Cached result of the last \see getPreprocessedEntitiesInRange Index: include/clang/Lex/Preprocessor.h =================================================================== --- include/clang/Lex/Preprocessor.h (revision 144239) +++ include/clang/Lex/Preprocessor.h (working copy) @@ -1008,7 +1008,8 @@ const DirectoryLookup *&CurDir, SmallVectorImpl *SearchPath, SmallVectorImpl *RelativePath, - StringRef *SuggestedModule); + StringRef *SuggestedModule, + bool SkipCache = false); /// GetCurLookup - The DirectoryLookup structure used to find the current /// FileEntry, if CurLexer is non-null and if applicable. This allows us to Index: tools/libclang/Indexing.cpp =================================================================== --- tools/libclang/Indexing.cpp (revision 144239) +++ tools/libclang/Indexing.cpp (working copy) @@ -52,7 +52,8 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath) { + StringRef RelativePath, + SmallVectorImpl &RecoveryPath) { bool isImport = (IncludeTok.is(tok::identifier) && IncludeTok.getIdentifierInfo()->getPPKeywordID() == tok::pp_import); IndexCtx.ppIncludedFile(HashLoc, FileName, File, isImport, IsAngled); Index: lib/Frontend/DependencyFile.cpp =================================================================== --- lib/Frontend/DependencyFile.cpp (revision 144239) +++ lib/Frontend/DependencyFile.cpp (working copy) @@ -61,7 +61,8 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath); + StringRef RelativePath, + SmallVectorImpl &RecoveryPath); virtual void EndOfMainFile() { OutputDependencyFile(); @@ -144,7 +145,8 @@ const FileEntry *File, SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath) { + StringRef RelativePath, + SmallVectorImpl &) { if (AddMissingHeaderDeps && !File) AddFilename(FileName); } Index: lib/Lex/PPDirectives.cpp =================================================================== --- lib/Lex/PPDirectives.cpp (revision 144239) +++ lib/Lex/PPDirectives.cpp (working copy) @@ -486,7 +486,8 @@ const DirectoryLookup *&CurDir, SmallVectorImpl *SearchPath, SmallVectorImpl *RelativePath, - StringRef *SuggestedModule) { + StringRef *SuggestedModule, + bool SkipCache) { // If the header lookup mechanism may be relative to the current file, pass in // info about where the current file is. const FileEntry *CurFileEnt = 0; @@ -510,7 +511,7 @@ CurDir = CurDirLookup; const FileEntry *FE = HeaderInfo.LookupFile( Filename, isAngled, FromDir, CurDir, CurFileEnt, - SearchPath, RelativePath, SuggestedModule); + SearchPath, RelativePath, SuggestedModule, SkipCache); if (FE) return FE; // Otherwise, see if this is a subframework header. If so, this is relative @@ -1285,10 +1286,25 @@ } // Notify the callback object that we've seen an inclusion directive. - if (Callbacks) + if (Callbacks) { + llvm::SmallString<128> RecoveryPath; Callbacks->InclusionDirective(HashLoc, IncludeTok, Filename, isAngled, File, - End, SearchPath, RelativePath); + End, SearchPath, RelativePath, RecoveryPath); + if (!File && !RecoveryPath.empty()) { + if (const DirectoryEntry *DE = FileMgr.getDirectory(RecoveryPath)) { + // Add the recovery path to the list of search paths. + DirectoryLookup DL(DE, SrcMgr::C_User, true, false); + HeaderInfo.AddSearchPath(DL, isAngled); + + // Try the lookup again skipping the cache. + File = LookupFile(Filename, isAngled, LookupFrom, CurDir, NULL, NULL, + AutoModuleImport? &SuggestedModule : 0, + /*SkipCache*/true); + } + } + } + if (File == 0) { if (!SuppressIncludeNotFoundError) Diag(FilenameTok, diag::err_pp_file_not_found) << Filename; Index: lib/Lex/HeaderSearch.cpp =================================================================== --- lib/Lex/HeaderSearch.cpp (revision 144239) +++ lib/Lex/HeaderSearch.cpp (working copy) @@ -334,7 +334,8 @@ const FileEntry *CurFileEnt, SmallVectorImpl *SearchPath, SmallVectorImpl *RelativePath, - StringRef *SuggestedModule) + StringRef *SuggestedModule, + bool SkipCache) { if (SuggestedModule) *SuggestedModule = StringRef(); @@ -410,7 +411,7 @@ // If the entry has been previously looked up, the first value will be // non-zero. If the value is equal to i (the start point of our search), then // this is a matching hit. - if (CacheLookup.first == i+1) { + if (!SkipCache && CacheLookup.first == i+1) { // Skip querying potentially lots of directories for this lookup. i = CacheLookup.second; } else { Index: lib/Lex/PreprocessingRecord.cpp =================================================================== --- lib/Lex/PreprocessingRecord.cpp (revision 144239) +++ lib/Lex/PreprocessingRecord.cpp (working copy) @@ -368,7 +368,8 @@ const FileEntry *File, clang::SourceLocation EndLoc, StringRef SearchPath, - StringRef RelativePath) { + StringRef RelativePath, + SmallVectorImpl &RecoveryPath) { InclusionDirective::InclusionKind Kind = InclusionDirective::Include; switch (IncludeTok.getIdentifierInfo()->getPPKeywordID()) {