Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 545 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/Tooling/InterpolatingCompilationDatabase.cpp b/gnu/llvm/clang/lib/Tooling/InterpolatingCompilationDatabase.cpp
new file mode 100644
index 00000000000..2cc819a498c
--- /dev/null
+++ b/gnu/llvm/clang/lib/Tooling/InterpolatingCompilationDatabase.cpp
@@ -0,0 +1,545 @@
+//===- 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);
+    }
+
+    // Make use of -std iff -x was missing.
+    if (Type == types::TY_INVALID && Std != LangStandard::lang_unspecified)
+      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