| //===- InterpolatingCompilationDatabase.cpp ---------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // InterpolatingCompilationDatabase wraps another CompilationDatabase and |
| // attempts to heuristically determine appropriate compile commands for files |
| // that are not included, such as headers or newly created files. |
| // |
| // Motivating cases include: |
| // Header files that live next to their implementation files. These typically |
| // share a base filename. (libclang/CXString.h, libclang/CXString.cpp). |
| // Some projects separate headers from includes. Filenames still typically |
| // match, maybe other path segments too. (include/llvm/IR/Use.h, lib/IR/Use.cc). |
| // Matches are sometimes only approximate (Sema.h, SemaDecl.cpp). This goes |
| // for directories too (Support/Unix/Process.inc, lib/Support/Process.cpp). |
| // Even if we can't find a "right" compile command, even a random one from |
| // the project will tend to get important flags like -I and -x right. |
| // |
| // We "borrow" the compile command for the closest available file: |
| // - points are awarded if the filename matches (ignoring extension) |
| // - points are awarded if the directory structure matches |
| // - ties are broken by length of path prefix match |
| // |
| // The compile command is adjusted, replacing the filename and removing output |
| // file arguments. The -x and -std flags may be affected too. |
| // |
| // Source language is a tricky issue: is it OK to use a .c file's command |
| // for building a .cc file? What language is a .h file in? |
| // - We only consider compile commands for c-family languages as candidates. |
| // - For files whose language is implied by the filename (e.g. .m, .hpp) |
| // we prefer candidates from the same language. |
| // If we must cross languages, we drop any -x and -std flags. |
| // - For .h files, candidates from any c-family language are acceptable. |
| // We use the candidate's language, inserting e.g. -x c++-header. |
| // |
| // This class is only useful when wrapping databases that can enumerate all |
| // their compile commands. If getAllFilenames() is empty, no inference occurs. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Basic/LangStandard.h" |
| #include "clang/Driver/Options.h" |
| #include "clang/Driver/Types.h" |
| #include "clang/Tooling/CompilationDatabase.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/StringSwitch.h" |
| #include "llvm/Option/ArgList.h" |
| #include "llvm/Option/OptTable.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/StringSaver.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <memory> |
| |
| namespace clang { |
| namespace tooling { |
| namespace { |
| using namespace llvm; |
| namespace types = clang::driver::types; |
| namespace path = llvm::sys::path; |
| |
| // The length of the prefix these two strings have in common. |
| size_t matchingPrefix(StringRef L, StringRef R) { |
| size_t Limit = std::min(L.size(), R.size()); |
| for (size_t I = 0; I < Limit; ++I) |
| if (L[I] != R[I]) |
| return I; |
| return Limit; |
| } |
| |
| // A comparator for searching SubstringWithIndexes with std::equal_range etc. |
| // Optionaly prefix semantics: compares equal if the key is a prefix. |
| template <bool Prefix> struct Less { |
| bool operator()(StringRef Key, std::pair<StringRef, size_t> Value) const { |
| StringRef V = Prefix ? Value.first.substr(0, Key.size()) : Value.first; |
| return Key < V; |
| } |
| bool operator()(std::pair<StringRef, size_t> Value, StringRef Key) const { |
| StringRef V = Prefix ? Value.first.substr(0, Key.size()) : Value.first; |
| return V < Key; |
| } |
| }; |
| |
| // Infer type from filename. If we might have gotten it wrong, set *Certain. |
| // *.h will be inferred as a C header, but not certain. |
| types::ID guessType(StringRef Filename, bool *Certain = nullptr) { |
| // path::extension is ".cpp", lookupTypeForExtension wants "cpp". |
| auto Lang = |
| types::lookupTypeForExtension(path::extension(Filename).substr(1)); |
| if (Certain) |
| *Certain = Lang != types::TY_CHeader && Lang != types::TY_INVALID; |
| return Lang; |
| } |
| |
| // Return Lang as one of the canonical supported types. |
| // e.g. c-header --> c; fortran --> TY_INVALID |
| static types::ID foldType(types::ID Lang) { |
| switch (Lang) { |
| case types::TY_C: |
| case types::TY_CHeader: |
| return types::TY_C; |
| case types::TY_ObjC: |
| case types::TY_ObjCHeader: |
| return types::TY_ObjC; |
| case types::TY_CXX: |
| case types::TY_CXXHeader: |
| return types::TY_CXX; |
| case types::TY_ObjCXX: |
| case types::TY_ObjCXXHeader: |
| return types::TY_ObjCXX; |
| default: |
| return types::TY_INVALID; |
| } |
| } |
| |
| // A CompileCommand that can be applied to another file. |
| struct TransferableCommand { |
| // Flags that should not apply to all files are stripped from CommandLine. |
| CompileCommand Cmd; |
| // Language detected from -x or the filename. Never TY_INVALID. |
| Optional<types::ID> Type; |
| // Standard specified by -std. |
| LangStandard::Kind Std = LangStandard::lang_unspecified; |
| // Whether the command line is for the cl-compatible driver. |
| bool ClangCLMode; |
| |
| TransferableCommand(CompileCommand C) |
| : Cmd(std::move(C)), Type(guessType(Cmd.Filename)), |
| ClangCLMode(checkIsCLMode(Cmd.CommandLine)) { |
| std::vector<std::string> OldArgs = std::move(Cmd.CommandLine); |
| Cmd.CommandLine.clear(); |
| |
| // Wrap the old arguments in an InputArgList. |
| llvm::opt::InputArgList ArgList; |
| { |
| SmallVector<const char *, 16> TmpArgv; |
| for (const std::string &S : OldArgs) |
| TmpArgv.push_back(S.c_str()); |
| ArgList = {TmpArgv.begin(), TmpArgv.end()}; |
| } |
| |
| // Parse the old args in order to strip out and record unwanted flags. |
| // We parse each argument individually so that we can retain the exact |
| // spelling of each argument; re-rendering is lossy for aliased flags. |
| // E.g. in CL mode, /W4 maps to -Wall. |
| auto &OptTable = clang::driver::getDriverOptTable(); |
| if (!OldArgs.empty()) |
| Cmd.CommandLine.emplace_back(OldArgs.front()); |
| for (unsigned Pos = 1; Pos < OldArgs.size();) { |
| using namespace driver::options; |
| |
| const unsigned OldPos = Pos; |
| std::unique_ptr<llvm::opt::Arg> Arg(OptTable.ParseOneArg( |
| ArgList, Pos, |
| /* Include */ ClangCLMode ? CoreOption | CLOption : 0, |
| /* Exclude */ ClangCLMode ? 0 : CLOption)); |
| |
| if (!Arg) |
| continue; |
| |
| const llvm::opt::Option &Opt = Arg->getOption(); |
| |
| // Strip input and output files. |
| if (Opt.matches(OPT_INPUT) || Opt.matches(OPT_o) || |
| (ClangCLMode && (Opt.matches(OPT__SLASH_Fa) || |
| Opt.matches(OPT__SLASH_Fe) || |
| Opt.matches(OPT__SLASH_Fi) || |
| Opt.matches(OPT__SLASH_Fo)))) |
| continue; |
| |
| // Strip -x, but record the overridden language. |
| if (const auto GivenType = tryParseTypeArg(*Arg)) { |
| Type = *GivenType; |
| continue; |
| } |
| |
| // Strip -std, but record the value. |
| if (const auto GivenStd = tryParseStdArg(*Arg)) { |
| if (*GivenStd != LangStandard::lang_unspecified) |
| Std = *GivenStd; |
| continue; |
| } |
| |
| Cmd.CommandLine.insert(Cmd.CommandLine.end(), |
| OldArgs.data() + OldPos, OldArgs.data() + Pos); |
| } |
| |
| if (Std != LangStandard::lang_unspecified) // -std take precedence over -x |
| Type = toType(LangStandard::getLangStandardForKind(Std).getLanguage()); |
| Type = foldType(*Type); |
| // The contract is to store None instead of TY_INVALID. |
| if (Type == types::TY_INVALID) |
| Type = llvm::None; |
| } |
| |
| // Produce a CompileCommand for \p filename, based on this one. |
| CompileCommand transferTo(StringRef Filename) const { |
| CompileCommand Result = Cmd; |
| Result.Filename = Filename; |
| bool TypeCertain; |
| auto TargetType = guessType(Filename, &TypeCertain); |
| // If the filename doesn't determine the language (.h), transfer with -x. |
| if ((!TargetType || !TypeCertain) && Type) { |
| // Use *Type, or its header variant if the file is a header. |
| // Treat no/invalid extension as header (e.g. C++ standard library). |
| TargetType = |
| (!TargetType || types::onlyPrecompileType(TargetType)) // header? |
| ? types::lookupHeaderTypeForSourceType(*Type) |
| : *Type; |
| if (ClangCLMode) { |
| const StringRef Flag = toCLFlag(TargetType); |
| if (!Flag.empty()) |
| Result.CommandLine.push_back(Flag); |
| } else { |
| Result.CommandLine.push_back("-x"); |
| Result.CommandLine.push_back(types::getTypeName(TargetType)); |
| } |
| } |
| // --std flag may only be transferred if the language is the same. |
| // We may consider "translating" these, e.g. c++11 -> c11. |
| if (Std != LangStandard::lang_unspecified && foldType(TargetType) == Type) { |
| Result.CommandLine.emplace_back(( |
| llvm::Twine(ClangCLMode ? "/std:" : "-std=") + |
| LangStandard::getLangStandardForKind(Std).getName()).str()); |
| } |
| Result.CommandLine.push_back(Filename); |
| Result.Heuristic = "inferred from " + Cmd.Filename; |
| return Result; |
| } |
| |
| private: |
| // Determine whether the given command line is intended for the CL driver. |
| static bool checkIsCLMode(ArrayRef<std::string> CmdLine) { |
| // First look for --driver-mode. |
| for (StringRef S : llvm::reverse(CmdLine)) { |
| if (S.consume_front("--driver-mode=")) |
| return S == "cl"; |
| } |
| |
| // Otherwise just check the clang executable file name. |
| return !CmdLine.empty() && |
| llvm::sys::path::stem(CmdLine.front()).endswith_lower("cl"); |
| } |
| |
| // Map the language from the --std flag to that of the -x flag. |
| static types::ID toType(Language Lang) { |
| switch (Lang) { |
| case Language::C: |
| return types::TY_C; |
| case Language::CXX: |
| return types::TY_CXX; |
| case Language::ObjC: |
| return types::TY_ObjC; |
| case Language::ObjCXX: |
| return types::TY_ObjCXX; |
| default: |
| return types::TY_INVALID; |
| } |
| } |
| |
| // Convert a file type to the matching CL-style type flag. |
| static StringRef toCLFlag(types::ID Type) { |
| switch (Type) { |
| case types::TY_C: |
| case types::TY_CHeader: |
| return "/TC"; |
| case types::TY_CXX: |
| case types::TY_CXXHeader: |
| return "/TP"; |
| default: |
| return StringRef(); |
| } |
| } |
| |
| // Try to interpret the argument as a type specifier, e.g. '-x'. |
| Optional<types::ID> tryParseTypeArg(const llvm::opt::Arg &Arg) { |
| const llvm::opt::Option &Opt = Arg.getOption(); |
| using namespace driver::options; |
| if (ClangCLMode) { |
| if (Opt.matches(OPT__SLASH_TC) || Opt.matches(OPT__SLASH_Tc)) |
| return types::TY_C; |
| if (Opt.matches(OPT__SLASH_TP) || Opt.matches(OPT__SLASH_Tp)) |
| return types::TY_CXX; |
| } else { |
| if (Opt.matches(driver::options::OPT_x)) |
| return types::lookupTypeForTypeSpecifier(Arg.getValue()); |
| } |
| return None; |
| } |
| |
| // Try to interpret the argument as '-std='. |
| Optional<LangStandard::Kind> tryParseStdArg(const llvm::opt::Arg &Arg) { |
| using namespace driver::options; |
| if (Arg.getOption().matches(ClangCLMode ? OPT__SLASH_std : OPT_std_EQ)) |
| return LangStandard::getLangKind(Arg.getValue()); |
| return None; |
| } |
| }; |
| |
| // Given a filename, FileIndex picks the best matching file from the underlying |
| // DB. This is the proxy file whose CompileCommand will be reused. The |
| // heuristics incorporate file name, extension, and directory structure. |
| // Strategy: |
| // - Build indexes of each of the substrings we want to look up by. |
| // These indexes are just sorted lists of the substrings. |
| // - Each criterion corresponds to a range lookup into the index, so we only |
| // need O(log N) string comparisons to determine scores. |
| // |
| // Apart from path proximity signals, also takes file extensions into account |
| // when scoring the candidates. |
| class FileIndex { |
| public: |
| FileIndex(std::vector<std::string> Files) |
| : OriginalPaths(std::move(Files)), Strings(Arena) { |
| // Sort commands by filename for determinism (index is a tiebreaker later). |
| llvm::sort(OriginalPaths); |
| Paths.reserve(OriginalPaths.size()); |
| Types.reserve(OriginalPaths.size()); |
| Stems.reserve(OriginalPaths.size()); |
| for (size_t I = 0; I < OriginalPaths.size(); ++I) { |
| StringRef Path = Strings.save(StringRef(OriginalPaths[I]).lower()); |
| |
| Paths.emplace_back(Path, I); |
| Types.push_back(foldType(guessType(Path))); |
| Stems.emplace_back(sys::path::stem(Path), I); |
| auto Dir = ++sys::path::rbegin(Path), DirEnd = sys::path::rend(Path); |
| for (int J = 0; J < DirectorySegmentsIndexed && Dir != DirEnd; ++J, ++Dir) |
| if (Dir->size() > ShortDirectorySegment) // not trivial ones |
| Components.emplace_back(*Dir, I); |
| } |
| llvm::sort(Paths); |
| llvm::sort(Stems); |
| llvm::sort(Components); |
| } |
| |
| bool empty() const { return Paths.empty(); } |
| |
| // Returns the path for the file that best fits OriginalFilename. |
| // Candidates with extensions matching PreferLanguage will be chosen over |
| // others (unless it's TY_INVALID, or all candidates are bad). |
| StringRef chooseProxy(StringRef OriginalFilename, |
| types::ID PreferLanguage) const { |
| assert(!empty() && "need at least one candidate!"); |
| std::string Filename = OriginalFilename.lower(); |
| auto Candidates = scoreCandidates(Filename); |
| std::pair<size_t, int> Best = |
| pickWinner(Candidates, Filename, PreferLanguage); |
| |
| DEBUG_WITH_TYPE( |
| "interpolate", |
| llvm::dbgs() << "interpolate: chose " << OriginalPaths[Best.first] |
| << " as proxy for " << OriginalFilename << " preferring " |
| << (PreferLanguage == types::TY_INVALID |
| ? "none" |
| : types::getTypeName(PreferLanguage)) |
| << " score=" << Best.second << "\n"); |
| return OriginalPaths[Best.first]; |
| } |
| |
| private: |
| using SubstringAndIndex = std::pair<StringRef, size_t>; |
| // Directory matching parameters: we look at the last two segments of the |
| // parent directory (usually the semantically significant ones in practice). |
| // We search only the last four of each candidate (for efficiency). |
| constexpr static int DirectorySegmentsIndexed = 4; |
| constexpr static int DirectorySegmentsQueried = 2; |
| constexpr static int ShortDirectorySegment = 1; // Only look at longer names. |
| |
| // Award points to candidate entries that should be considered for the file. |
| // Returned keys are indexes into paths, and the values are (nonzero) scores. |
| DenseMap<size_t, int> scoreCandidates(StringRef Filename) const { |
| // Decompose Filename into the parts we care about. |
| // /some/path/complicated/project/Interesting.h |
| // [-prefix--][---dir---] [-dir-] [--stem---] |
| StringRef Stem = sys::path::stem(Filename); |
| llvm::SmallVector<StringRef, DirectorySegmentsQueried> Dirs; |
| llvm::StringRef Prefix; |
| auto Dir = ++sys::path::rbegin(Filename), |
| DirEnd = sys::path::rend(Filename); |
| for (int I = 0; I < DirectorySegmentsQueried && Dir != DirEnd; ++I, ++Dir) { |
| if (Dir->size() > ShortDirectorySegment) |
| Dirs.push_back(*Dir); |
| Prefix = Filename.substr(0, Dir - DirEnd); |
| } |
| |
| // Now award points based on lookups into our various indexes. |
| DenseMap<size_t, int> Candidates; // Index -> score. |
| auto Award = [&](int Points, ArrayRef<SubstringAndIndex> Range) { |
| for (const auto &Entry : Range) |
| Candidates[Entry.second] += Points; |
| }; |
| // Award one point if the file's basename is a prefix of the candidate, |
| // and another if it's an exact match (so exact matches get two points). |
| Award(1, indexLookup</*Prefix=*/true>(Stem, Stems)); |
| Award(1, indexLookup</*Prefix=*/false>(Stem, Stems)); |
| // For each of the last few directories in the Filename, award a point |
| // if it's present in the candidate. |
| for (StringRef Dir : Dirs) |
| Award(1, indexLookup</*Prefix=*/false>(Dir, Components)); |
| // Award one more point if the whole rest of the path matches. |
| if (sys::path::root_directory(Prefix) != Prefix) |
| Award(1, indexLookup</*Prefix=*/true>(Prefix, Paths)); |
| return Candidates; |
| } |
| |
| // Pick a single winner from the set of scored candidates. |
| // Returns (index, score). |
| std::pair<size_t, int> pickWinner(const DenseMap<size_t, int> &Candidates, |
| StringRef Filename, |
| types::ID PreferredLanguage) const { |
| struct ScoredCandidate { |
| size_t Index; |
| bool Preferred; |
| int Points; |
| size_t PrefixLength; |
| }; |
| // Choose the best candidate by (preferred, points, prefix length, alpha). |
| ScoredCandidate Best = {size_t(-1), false, 0, 0}; |
| for (const auto &Candidate : Candidates) { |
| ScoredCandidate S; |
| S.Index = Candidate.first; |
| S.Preferred = PreferredLanguage == types::TY_INVALID || |
| PreferredLanguage == Types[S.Index]; |
| S.Points = Candidate.second; |
| if (!S.Preferred && Best.Preferred) |
| continue; |
| if (S.Preferred == Best.Preferred) { |
| if (S.Points < Best.Points) |
| continue; |
| if (S.Points == Best.Points) { |
| S.PrefixLength = matchingPrefix(Filename, Paths[S.Index].first); |
| if (S.PrefixLength < Best.PrefixLength) |
| continue; |
| // hidden heuristics should at least be deterministic! |
| if (S.PrefixLength == Best.PrefixLength) |
| if (S.Index > Best.Index) |
| continue; |
| } |
| } |
| // PrefixLength was only set above if actually needed for a tiebreak. |
| // But it definitely needs to be set to break ties in the future. |
| S.PrefixLength = matchingPrefix(Filename, Paths[S.Index].first); |
| Best = S; |
| } |
| // Edge case: no candidate got any points. |
| // We ignore PreferredLanguage at this point (not ideal). |
| if (Best.Index == size_t(-1)) |
| return {longestMatch(Filename, Paths).second, 0}; |
| return {Best.Index, Best.Points}; |
| } |
| |
| // Returns the range within a sorted index that compares equal to Key. |
| // If Prefix is true, it's instead the range starting with Key. |
| template <bool Prefix> |
| ArrayRef<SubstringAndIndex> |
| indexLookup(StringRef Key, ArrayRef<SubstringAndIndex> Idx) const { |
| // Use pointers as iteratiors to ease conversion of result to ArrayRef. |
| auto Range = std::equal_range(Idx.data(), Idx.data() + Idx.size(), Key, |
| Less<Prefix>()); |
| return {Range.first, Range.second}; |
| } |
| |
| // Performs a point lookup into a nonempty index, returning a longest match. |
| SubstringAndIndex longestMatch(StringRef Key, |
| ArrayRef<SubstringAndIndex> Idx) const { |
| assert(!Idx.empty()); |
| // Longest substring match will be adjacent to a direct lookup. |
| auto It = llvm::lower_bound(Idx, SubstringAndIndex{Key, 0}); |
| if (It == Idx.begin()) |
| return *It; |
| if (It == Idx.end()) |
| return *--It; |
| // Have to choose between It and It-1 |
| size_t Prefix = matchingPrefix(Key, It->first); |
| size_t PrevPrefix = matchingPrefix(Key, (It - 1)->first); |
| return Prefix > PrevPrefix ? *It : *--It; |
| } |
| |
| // Original paths, everything else is in lowercase. |
| std::vector<std::string> OriginalPaths; |
| BumpPtrAllocator Arena; |
| StringSaver Strings; |
| // Indexes of candidates by certain substrings. |
| // String is lowercase and sorted, index points into OriginalPaths. |
| std::vector<SubstringAndIndex> Paths; // Full path. |
| // Lang types obtained by guessing on the corresponding path. I-th element is |
| // a type for the I-th path. |
| std::vector<types::ID> Types; |
| std::vector<SubstringAndIndex> Stems; // Basename, without extension. |
| std::vector<SubstringAndIndex> Components; // Last path components. |
| }; |
| |
| // The actual CompilationDatabase wrapper delegates to its inner database. |
| // If no match, looks up a proxy file in FileIndex and transfers its |
| // command to the requested file. |
| class InterpolatingCompilationDatabase : public CompilationDatabase { |
| public: |
| InterpolatingCompilationDatabase(std::unique_ptr<CompilationDatabase> Inner) |
| : Inner(std::move(Inner)), Index(this->Inner->getAllFiles()) {} |
| |
| std::vector<CompileCommand> |
| getCompileCommands(StringRef Filename) const override { |
| auto Known = Inner->getCompileCommands(Filename); |
| if (Index.empty() || !Known.empty()) |
| return Known; |
| bool TypeCertain; |
| auto Lang = guessType(Filename, &TypeCertain); |
| if (!TypeCertain) |
| Lang = types::TY_INVALID; |
| auto ProxyCommands = |
| Inner->getCompileCommands(Index.chooseProxy(Filename, foldType(Lang))); |
| if (ProxyCommands.empty()) |
| return {}; |
| return {TransferableCommand(ProxyCommands[0]).transferTo(Filename)}; |
| } |
| |
| std::vector<std::string> getAllFiles() const override { |
| return Inner->getAllFiles(); |
| } |
| |
| std::vector<CompileCommand> getAllCompileCommands() const override { |
| return Inner->getAllCompileCommands(); |
| } |
| |
| private: |
| std::unique_ptr<CompilationDatabase> Inner; |
| FileIndex Index; |
| }; |
| |
| } // namespace |
| |
| std::unique_ptr<CompilationDatabase> |
| inferMissingCompileCommands(std::unique_ptr<CompilationDatabase> Inner) { |
| return std::make_unique<InterpolatingCompilationDatabase>(std::move(Inner)); |
| } |
| |
| } // namespace tooling |
| } // namespace clang |