clang-tools-extra/clangd/SystemIncludeExtractor.cpp

   1 //===--- SystemIncludeExtractor.cpp ------------------------------*- C++-*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 // Some compiler drivers have implicit search mechanism for system headers.
   9 // This compilation database implementation tries to extract that information by
  10 // executing the driver in verbose mode. gcc-compatible drivers print something
  11 // like:
  12 // ....
  13 // ....
  14 // #include <...> search starts here:
  15 //  /usr/lib/gcc/x86_64-linux-gnu/7/include
  16 //  /usr/local/include
  17 //  /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed
  18 //  /usr/include/x86_64-linux-gnu
  19 //  /usr/include
  20 // End of search list.
  21 // ....
  22 // ....
  23 // This component parses that output and adds each path to command line args
  24 // provided by Base, after prepending them with -isystem. Therefore current
  25 // implementation would not work with a driver that is not gcc-compatible.
  26 //
  27 // First argument of the command line received from underlying compilation
  28 // database is used as compiler driver path. Due to this arbitrary binary
  29 // execution, this mechanism is not used by default and only executes binaries
  30 // in the paths that are explicitly included by the user.
  31
  32 #include "CompileCommands.h"
  33 #include "GlobalCompilationDatabase.h"
  34 #include "support/Logger.h"
  35 #include "support/Threading.h"
  36 #include "support/Trace.h"
  37 #include "clang/Basic/Diagnostic.h"
  38 #include "clang/Basic/DiagnosticIDs.h"
  39 #include "clang/Basic/DiagnosticOptions.h"
  40 #include "clang/Basic/TargetInfo.h"
  41 #include "clang/Basic/TargetOptions.h"
  42 #include "clang/Driver/Types.h"
  43 #include "clang/Tooling/CompilationDatabase.h"
  44 #include "llvm/ADT/ArrayRef.h"
  45 #include "llvm/ADT/DenseMap.h"
  46 #include "llvm/ADT/Hashing.h"
  47 #include "llvm/ADT/IntrusiveRefCntPtr.h"
  48 #include "llvm/ADT/STLExtras.h"
  49 #include "llvm/ADT/ScopeExit.h"
  50 #include "llvm/ADT/SmallString.h"
  51 #include "llvm/ADT/SmallVector.h"
  52 #include "llvm/ADT/StringExtras.h"
  53 #include "llvm/ADT/StringRef.h"
  54 #include "llvm/Support/ErrorHandling.h"
  55 #include "llvm/Support/FileSystem.h"
  56 #include "llvm/Support/MemoryBuffer.h"
  57 #include "llvm/Support/Path.h"
  58 #include "llvm/Support/Program.h"
  59 #include "llvm/Support/Regex.h"
  60 #include "llvm/Support/ScopedPrinter.h"
  61 #include "llvm/Support/raw_ostream.h"
  62 #include <cassert>
  63 #include <cstddef>
  64 #include <iterator>
  65 #include <memory>
  66 #include <optional>
  67 #include <string>
  68 #include <tuple>
  69 #include <utility>
  70 #include <vector>
  71
  72 namespace clang::clangd {
  73 namespace {
  74
  75 struct DriverInfo {
  76   std::vector<std::string> SystemIncludes;
  77   std::string Target;
  78 };
  79
  80 struct DriverArgs {
  81   // Name of the driver program to execute or absolute path to it.
  82   std::string Driver;
  83   // Whether certain includes should be part of query.
  84   bool StandardIncludes = true;
  85   bool StandardCXXIncludes = true;
  86   // Language to use while querying.
  87   std::string Lang;
  88   std::string Sysroot;
  89   std::string ISysroot;
  90   std::string Target;
  91   std::string Stdlib;
  92   llvm::SmallVector<std::string> Specs;
  93
  94   bool operator==(const DriverArgs &RHS) const {
  95     return std::tie(Driver, StandardIncludes, StandardCXXIncludes, Lang,
  96                     Sysroot, ISysroot, Target, Stdlib, Specs) ==
  97            std::tie(RHS.Driver, RHS.StandardIncludes, RHS.StandardCXXIncludes,
  98                     RHS.Lang, RHS.Sysroot, RHS.ISysroot, RHS.Target, RHS.Stdlib,
  99                     RHS.Specs);
 100   }
 101
 102   DriverArgs(const tooling::CompileCommand &Cmd, llvm::StringRef File) {
 103     llvm::SmallString<128> Driver(Cmd.CommandLine.front());
 104     // Driver is a not a single executable name but instead a path (either
 105     // relative or absolute).
 106     if (llvm::any_of(Driver,
 107                      [](char C) { return llvm::sys::path::is_separator(C); })) {
 108       llvm::sys::fs::make_absolute(Cmd.Directory, Driver);
 109     }
 110     this->Driver = Driver.str().str();
 111     for (size_t I = 0, E = Cmd.CommandLine.size(); I < E; ++I) {
 112       llvm::StringRef Arg = Cmd.CommandLine[I];
 113
 114       // Look for Language related flags.
 115       if (Arg.consume_front("-x")) {
 116         if (Arg.empty() && I + 1 < E)
 117           Lang = Cmd.CommandLine[I + 1];
 118         else
 119           Lang = Arg.str();
 120       }
 121       // Look for standard/builtin includes.
 122       else if (Arg == "-nostdinc" || Arg == "--no-standard-includes")
 123         StandardIncludes = false;
 124       else if (Arg == "-nostdinc++")
 125         StandardCXXIncludes = false;
 126       // Figure out sysroot
 127       else if (Arg.consume_front("--sysroot")) {
 128         if (Arg.consume_front("="))
 129           Sysroot = Arg.str();
 130         else if (Arg.empty() && I + 1 < E)
 131           Sysroot = Cmd.CommandLine[I + 1];
 132       } else if (Arg.consume_front("-isysroot")) {
 133         if (Arg.empty() && I + 1 < E)
 134           ISysroot = Cmd.CommandLine[I + 1];
 135         else
 136           ISysroot = Arg.str();
 137       } else if (Arg.consume_front("--target=")) {
 138         Target = Arg.str();
 139       } else if (Arg.consume_front("-target")) {
 140         if (Arg.empty() && I + 1 < E)
 141           Target = Cmd.CommandLine[I + 1];
 142       } else if (Arg.consume_front("--stdlib")) {
 143         if (Arg.consume_front("="))
 144           Stdlib = Arg.str();
 145         else if (Arg.empty() && I + 1 < E)
 146           Stdlib = Cmd.CommandLine[I + 1];
 147       } else if (Arg.consume_front("-stdlib=")) {
 148         Stdlib = Arg.str();
 149       } else if (Arg.starts_with("-specs=")) {
 150         // clang requires a single token like `-specs=file` or `--specs=file`,
 151         // but gcc will accept two tokens like `--specs file`. Since the
 152         // compilation database is presumably correct, we just forward the flags
 153         // as-is.
 154         Specs.push_back(Arg.str());
 155       } else if (Arg.starts_with("--specs=")) {
 156         Specs.push_back(Arg.str());
 157       } else if (Arg == "--specs" && I + 1 < E) {
 158         Specs.push_back(Arg.str());
 159         Specs.push_back(Cmd.CommandLine[I + 1]);
 160       }
 161     }
 162
 163     // Downgrade objective-c++-header (used in clangd's fallback flags for .h
 164     // files) to c++-header, as some drivers may fail to run the extraction
 165     // command if it contains `-xobjective-c++-header` and objective-c++ support
 166     // is not installed.
 167     // In practice, we don't see different include paths for the two on
 168     // clang+mac, which is the most common objectve-c compiler.
 169     if (Lang == "objective-c++-header") {
 170       Lang = "c++-header";
 171     }
 172
 173     // If language is not explicit in the flags, infer from the file.
 174     // This is important as we want to cache each language separately.
 175     if (Lang.empty()) {
 176       llvm::StringRef Ext = llvm::sys::path::extension(File).trim('.');
 177       auto Type = driver::types::lookupTypeForExtension(Ext);
 178       if (Type == driver::types::TY_INVALID) {
 179         elog("System include extraction: invalid file type for {0}", Ext);
 180       } else {
 181         Lang = driver::types::getTypeName(Type);
 182       }
 183     }
 184   }
 185   llvm::SmallVector<llvm::StringRef> render() const {
 186     // FIXME: Don't treat lang specially?
 187     assert(!Lang.empty());
 188     llvm::SmallVector<llvm::StringRef> Args = {"-x", Lang};
 189     if (!StandardIncludes)
 190       Args.push_back("-nostdinc");
 191     if (!StandardCXXIncludes)
 192       Args.push_back("-nostdinc++");
 193     if (!Sysroot.empty())
 194       Args.append({"--sysroot", Sysroot});
 195     if (!ISysroot.empty())
 196       Args.append({"-isysroot", ISysroot});
 197     if (!Target.empty())
 198       Args.append({"-target", Target});
 199     if (!Stdlib.empty())
 200       Args.append({"--stdlib", Stdlib});
 201
 202     for (llvm::StringRef Spec : Specs) {
 203       Args.push_back(Spec);
 204     }
 205
 206     return Args;
 207   }
 208
 209   static DriverArgs getEmpty() { return {}; }
 210
 211 private:
 212   DriverArgs() = default;
 213 };
 214 } // namespace
 215 } // namespace clang::clangd
 216 namespace llvm {
 217 using DriverArgs = clang::clangd::DriverArgs;
 218 template <> struct DenseMapInfo<DriverArgs> {
 219   static DriverArgs getEmptyKey() {
 220     auto Driver = DriverArgs::getEmpty();
 221     Driver.Driver = "EMPTY_KEY";
 222     return Driver;
 223   }
 224   static DriverArgs getTombstoneKey() {
 225     auto Driver = DriverArgs::getEmpty();
 226     Driver.Driver = "TOMBSTONE_KEY";
 227     return Driver;
 228   }
 229   static unsigned getHashValue(const DriverArgs &Val) {
 230     unsigned FixedFieldsHash = llvm::hash_value(std::tuple{
 231         Val.Driver,
 232         Val.StandardIncludes,
 233         Val.StandardCXXIncludes,
 234         Val.Lang,
 235         Val.Sysroot,
 236         Val.ISysroot,
 237         Val.Target,
 238         Val.Stdlib,
 239     });
 240
 241     unsigned SpecsHash =
 242         llvm::hash_combine_range(Val.Specs.begin(), Val.Specs.end());
 243
 244     return llvm::hash_combine(FixedFieldsHash, SpecsHash);
 245   }
 246   static bool isEqual(const DriverArgs &LHS, const DriverArgs &RHS) {
 247     return LHS == RHS;
 248   }
 249 };
 250 } // namespace llvm
 251 namespace clang::clangd {
 252 namespace {
 253 bool isValidTarget(llvm::StringRef Triple) {
 254   std::shared_ptr<TargetOptions> TargetOpts(new TargetOptions);
 255   TargetOpts->Triple = Triple.str();
 256   DiagnosticsEngine Diags(new DiagnosticIDs, new DiagnosticOptions,
 257                           new IgnoringDiagConsumer);
 258   llvm::IntrusiveRefCntPtr<TargetInfo> Target =
 259       TargetInfo::CreateTargetInfo(Diags, TargetOpts);
 260   return bool(Target);
 261 }
 262
 263 std::optional<DriverInfo> parseDriverOutput(llvm::StringRef Output) {
 264   DriverInfo Info;
 265   const char SIS[] = "#include <...> search starts here:";
 266   const char SIE[] = "End of search list.";
 267   const char TS[] = "Target: ";
 268   llvm::SmallVector<llvm::StringRef> Lines;
 269   Output.split(Lines, '\n', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
 270
 271   enum {
 272     Initial,            // Initial state: searching for target or includes list.
 273     IncludesExtracting, // Includes extracting.
 274     Done                // Includes and target extraction done.
 275   } State = Initial;
 276   bool SeenIncludes = false;
 277   bool SeenTarget = false;
 278   for (auto *It = Lines.begin(); State != Done && It != Lines.end(); ++It) {
 279     auto Line = *It;
 280     switch (State) {
 281     case Initial:
 282       if (!SeenIncludes && Line.trim() == SIS) {
 283         SeenIncludes = true;
 284         State = IncludesExtracting;
 285       } else if (!SeenTarget && Line.trim().starts_with(TS)) {
 286         SeenTarget = true;
 287         llvm::StringRef TargetLine = Line.trim();
 288         TargetLine.consume_front(TS);
 289         // Only detect targets that clang understands
 290         if (!isValidTarget(TargetLine)) {
 291           elog("System include extraction: invalid target \"{0}\", ignoring",
 292                TargetLine);
 293         } else {
 294           Info.Target = TargetLine.str();
 295           vlog("System include extraction: target extracted: \"{0}\"",
 296                TargetLine);
 297         }
 298       }
 299       break;
 300     case IncludesExtracting:
 301       if (Line.trim() == SIE) {
 302         State = SeenTarget ? Done : Initial;
 303       } else {
 304         Info.SystemIncludes.push_back(Line.trim().str());
 305         vlog("System include extraction: adding {0}", Line);
 306       }
 307       break;
 308     default:
 309       llvm_unreachable("Impossible state of the driver output parser");
 310       break;
 311     }
 312   }
 313   if (!SeenIncludes) {
 314     elog("System include extraction: start marker not found: {0}", Output);
 315     return std::nullopt;
 316   }
 317   if (State == IncludesExtracting) {
 318     elog("System include extraction: end marker missing: {0}", Output);
 319     return std::nullopt;
 320   }
 321   return std::move(Info);
 322 }
 323
 324 std::optional<std::string> run(llvm::ArrayRef<llvm::StringRef> Argv,
 325                                bool OutputIsStderr) {
 326   llvm::SmallString<128> OutputPath;
 327   if (auto EC = llvm::sys::fs::createTemporaryFile("system-includes", "clangd",
 328                                                    OutputPath)) {
 329     elog("System include extraction: failed to create temporary file with "
 330          "error {0}",
 331          EC.message());
 332     return std::nullopt;
 333   }
 334   auto CleanUp = llvm::make_scope_exit(
 335       [&OutputPath]() { llvm::sys::fs::remove(OutputPath); });
 336
 337   std::optional<llvm::StringRef> Redirects[] = {{""}, {""}, {""}};
 338   Redirects[OutputIsStderr ? 2 : 1] = OutputPath.str();
 339
 340   std::string ErrMsg;
 341   if (int RC =
 342           llvm::sys::ExecuteAndWait(Argv.front(), Argv, /*Env=*/std::nullopt,
 343                                     Redirects, /*SecondsToWait=*/0,
 344                                     /*MemoryLimit=*/0, &ErrMsg)) {
 345     elog("System include extraction: driver execution failed with return code: "
 346          "{0} - '{1}'. Args: [{2}]",
 347          llvm::to_string(RC), ErrMsg, printArgv(Argv));
 348     return std::nullopt;
 349   }
 350
 351   auto BufOrError = llvm::MemoryBuffer::getFile(OutputPath);
 352   if (!BufOrError) {
 353     elog("System include extraction: failed to read {0} with error {1}",
 354          OutputPath, BufOrError.getError().message());
 355     return std::nullopt;
 356   }
 357   return BufOrError.get().get()->getBuffer().str();
 358 }
 359
 360 std::optional<DriverInfo>
 361 extractSystemIncludesAndTarget(const DriverArgs &InputArgs,
 362                                const llvm::Regex &QueryDriverRegex) {
 363   trace::Span Tracer("Extract system includes and target");
 364
 365   std::string Driver = InputArgs.Driver;
 366   if (!llvm::sys::path::is_absolute(Driver)) {
 367     auto DriverProgram = llvm::sys::findProgramByName(Driver);
 368     if (DriverProgram) {
 369       vlog("System include extraction: driver {0} expanded to {1}", Driver,
 370            *DriverProgram);
 371       Driver = *DriverProgram;
 372     } else {
 373       elog("System include extraction: driver {0} not found in PATH", Driver);
 374       return std::nullopt;
 375     }
 376   }
 377
 378   SPAN_ATTACH(Tracer, "driver", Driver);
 379   SPAN_ATTACH(Tracer, "lang", InputArgs.Lang);
 380
 381   // If driver was "../foo" then having to allowlist "/path/a/../foo" rather
 382   // than "/path/foo" is absurd.
 383   // Allow either to match the allowlist, then proceed with "/path/a/../foo".
 384   // This was our historical behavior, and it *could* resolve to something else.
 385   llvm::SmallString<256> NoDots(Driver);
 386   llvm::sys::path::remove_dots(NoDots, /*remove_dot_dot=*/true);
 387   if (!QueryDriverRegex.match(Driver) && !QueryDriverRegex.match(NoDots)) {
 388     vlog("System include extraction: not allowed driver {0}", Driver);
 389     return std::nullopt;
 390   }
 391
 392   llvm::SmallVector<llvm::StringRef> Args = {Driver, "-E", "-v"};
 393   Args.append(InputArgs.render());
 394   // Input needs to go after Lang flags.
 395   Args.push_back("-");
 396   auto Output = run(Args, /*OutputIsStderr=*/true);
 397   if (!Output)
 398     return std::nullopt;
 399
 400   std::optional<DriverInfo> Info = parseDriverOutput(*Output);
 401   if (!Info)
 402     return std::nullopt;
 403
 404   // The built-in headers are tightly coupled to parser builtins.
 405   // (These are clang's "resource dir", GCC's GCC_INCLUDE_DIR.)
 406   // We should keep using clangd's versions, so exclude the queried builtins.
 407   // They're not specially marked in the -v output, but we can get the path
 408   // with `$DRIVER -print-file-name=include`.
 409   if (auto BuiltinHeaders =
 410           run({Driver, "-print-file-name=include"}, /*OutputIsStderr=*/false)) {
 411     auto Path = llvm::StringRef(*BuiltinHeaders).trim();
 412     if (!Path.empty() && llvm::sys::path::is_absolute(Path)) {
 413       auto Size = Info->SystemIncludes.size();
 414       llvm::erase(Info->SystemIncludes, Path);
 415       vlog("System includes extractor: builtin headers {0} {1}", Path,
 416            (Info->SystemIncludes.size() != Size)
 417                ? "excluded"
 418                : "not found in driver's response");
 419     }
 420   }
 421
 422   log("System includes extractor: successfully executed {0}\n\tgot includes: "
 423       "\"{1}\"\n\tgot target: \"{2}\"",
 424       Driver, llvm::join(Info->SystemIncludes, ", "), Info->Target);
 425   return Info;
 426 }
 427
 428 tooling::CompileCommand &
 429 addSystemIncludes(tooling::CompileCommand &Cmd,
 430                   llvm::ArrayRef<std::string> SystemIncludes) {
 431   std::vector<std::string> ToAppend;
 432   for (llvm::StringRef Include : SystemIncludes) {
 433     // FIXME(kadircet): This doesn't work when we have "--driver-mode=cl"
 434     ToAppend.push_back("-isystem");
 435     ToAppend.push_back(Include.str());
 436   }
 437   if (!ToAppend.empty()) {
 438     // Just append when `--` isn't present.
 439     auto InsertAt = llvm::find(Cmd.CommandLine, "--");
 440     Cmd.CommandLine.insert(InsertAt, std::make_move_iterator(ToAppend.begin()),
 441                            std::make_move_iterator(ToAppend.end()));
 442   }
 443   return Cmd;
 444 }
 445
 446 tooling::CompileCommand &setTarget(tooling::CompileCommand &Cmd,
 447                                    const std::string &Target) {
 448   if (!Target.empty()) {
 449     // We do not want to override existing target with extracted one.
 450     for (llvm::StringRef Arg : Cmd.CommandLine) {
 451       if (Arg == "-target" || Arg.starts_with("--target="))
 452         return Cmd;
 453     }
 454     // Just append when `--` isn't present.
 455     auto InsertAt = llvm::find(Cmd.CommandLine, "--");
 456     Cmd.CommandLine.insert(InsertAt, "--target=" + Target);
 457   }
 458   return Cmd;
 459 }
 460
 461 /// Converts a glob containing only ** or * into a regex.
 462 std::string convertGlobToRegex(llvm::StringRef Glob) {
 463   std::string RegText;
 464   llvm::raw_string_ostream RegStream(RegText);
 465   RegStream << '^';
 466   for (size_t I = 0, E = Glob.size(); I < E; ++I) {
 467     if (Glob[I] == '*') {
 468       if (I + 1 < E && Glob[I + 1] == '*') {
 469         // Double star, accept any sequence.
 470         RegStream << ".*";
 471         // Also skip the second star.
 472         ++I;
 473       } else {
 474         // Single star, accept any sequence without a slash.
 475         RegStream << "[^/]*";
 476       }
 477     } else if (llvm::sys::path::is_separator(Glob[I]) &&
 478                llvm::sys::path::is_separator('/') &&
 479                llvm::sys::path::is_separator('\\')) {
 480       RegStream << R"([/\\])"; // Accept either slash on windows.
 481     } else {
 482       RegStream << llvm::Regex::escape(Glob.substr(I, 1));
 483     }
 484   }
 485   RegStream << '$';
 486   RegStream.flush();
 487   return RegText;
 488 }
 489
 490 /// Converts a glob containing only ** or * into a regex.
 491 llvm::Regex convertGlobsToRegex(llvm::ArrayRef<std::string> Globs) {
 492   assert(!Globs.empty() && "Globs cannot be empty!");
 493   std::vector<std::string> RegTexts;
 494   RegTexts.reserve(Globs.size());
 495   for (llvm::StringRef Glob : Globs)
 496     RegTexts.push_back(convertGlobToRegex(Glob));
 497
 498   // Tempting to pass IgnoreCase, but we don't know the FS sensitivity.
 499   llvm::Regex Reg(llvm::join(RegTexts, "|"));
 500   assert(Reg.isValid(RegTexts.front()) &&
 501          "Created an invalid regex from globs");
 502   return Reg;
 503 }
 504
 505 /// Extracts system includes from a trusted driver by parsing the output of
 506 /// include search path and appends them to the commands coming from underlying
 507 /// compilation database.
 508 class SystemIncludeExtractor {
 509 public:
 510   SystemIncludeExtractor(llvm::ArrayRef<std::string> QueryDriverGlobs)
 511       : QueryDriverRegex(convertGlobsToRegex(QueryDriverGlobs)) {}
 512
 513   void operator()(tooling::CompileCommand &Cmd, llvm::StringRef File) const {
 514     if (Cmd.CommandLine.empty())
 515       return;
 516
 517     DriverArgs Args(Cmd, File);
 518     if (Args.Lang.empty())
 519       return;
 520     if (auto Info = QueriedDrivers.get(Args, [&] {
 521           return extractSystemIncludesAndTarget(Args, QueryDriverRegex);
 522         })) {
 523       setTarget(addSystemIncludes(Cmd, Info->SystemIncludes), Info->Target);
 524     }
 525   }
 526
 527 private:
 528   // Caches includes extracted from a driver. Key is driver:lang.
 529   Memoize<llvm::DenseMap<DriverArgs, std::optional<DriverInfo>>> QueriedDrivers;
 530   llvm::Regex QueryDriverRegex;
 531 };
 532 } // namespace
 533
 534 SystemIncludeExtractorFn
 535 getSystemIncludeExtractor(llvm::ArrayRef<std::string> QueryDriverGlobs) {
 536   if (QueryDriverGlobs.empty())
 537     return nullptr;
 538   return SystemIncludeExtractor(QueryDriverGlobs);
 539 }
 540
 541 } // namespace clang::clangd