lib/Driver/SanitizerArgs.cpp

   1 //===--- SanitizerArgs.cpp - Arguments for sanitizer tools  ---------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 #include "clang/Driver/SanitizerArgs.h"
  10 #include "ToolChains/CommonArgs.h"
  11 #include "clang/Basic/Sanitizers.h"
  12 #include "clang/Driver/Driver.h"
  13 #include "clang/Driver/DriverDiagnostic.h"
  14 #include "clang/Driver/Options.h"
  15 #include "clang/Driver/ToolChain.h"
  16 #include "llvm/ADT/StringExtras.h"
  17 #include "llvm/ADT/StringSwitch.h"
  18 #include "llvm/Support/FileSystem.h"
  19 #include "llvm/Support/Path.h"
  20 #include "llvm/Support/SpecialCaseList.h"
  21 #include "llvm/Support/TargetParser.h"
  22 #include <memory>
  23
  24 using namespace clang;
  25 using namespace clang::SanitizerKind;
  26 using namespace clang::driver;
  27 using namespace llvm::opt;
  28
  29 enum : SanitizerMask {
  30   NeedsUbsanRt = Undefined | Integer | Nullability | CFI,
  31   NeedsUbsanCxxRt = Vptr | CFI,
  32   NotAllowedWithTrap = Vptr,
  33   NotAllowedWithMinimalRuntime = Vptr,
  34   RequiresPIE = DataFlow | HWAddress | Scudo,
  35   NeedsUnwindTables = Address | HWAddress | Thread | Memory | DataFlow,
  36   SupportsCoverage = Address | HWAddress | KernelAddress | KernelHWAddress |
  37                      Memory | Leak | Undefined | Integer | Nullability |
  38                      DataFlow | Fuzzer | FuzzerNoLink,
  39   RecoverableByDefault = Undefined | Integer | Nullability,
  40   Unrecoverable = Unreachable | Return,
  41   AlwaysRecoverable = KernelAddress | KernelHWAddress,
  42   LegacyFsanitizeRecoverMask = Undefined | Integer,
  43   NeedsLTO = CFI,
  44   TrappingSupported = (Undefined & ~Vptr) | UnsignedIntegerOverflow |
  45                       Nullability | LocalBounds | CFI,
  46   TrappingDefault = CFI,
  47   CFIClasses =
  48       CFIVCall | CFINVCall | CFIMFCall | CFIDerivedCast | CFIUnrelatedCast,
  49   CompatibleWithMinimalRuntime = TrappingSupported | Scudo,
  50 };
  51
  52 enum CoverageFeature {
  53   CoverageFunc = 1 << 0,
  54   CoverageBB = 1 << 1,
  55   CoverageEdge = 1 << 2,
  56   CoverageIndirCall = 1 << 3,
  57   CoverageTraceBB = 1 << 4,  // Deprecated.
  58   CoverageTraceCmp = 1 << 5,
  59   CoverageTraceDiv = 1 << 6,
  60   CoverageTraceGep = 1 << 7,
  61   Coverage8bitCounters = 1 << 8,  // Deprecated.
  62   CoverageTracePC = 1 << 9,
  63   CoverageTracePCGuard = 1 << 10,
  64   CoverageNoPrune = 1 << 11,
  65   CoverageInline8bitCounters = 1 << 12,
  66   CoveragePCTable = 1 << 13,
  67   CoverageStackDepth = 1 << 14,
  68 };
  69
  70 /// Parse a -fsanitize= or -fno-sanitize= argument's values, diagnosing any
  71 /// invalid components. Returns a SanitizerMask.
  72 static SanitizerMask parseArgValues(const Driver &D, const llvm::opt::Arg *A,
  73                                     bool DiagnoseErrors);
  74
  75 /// Parse -f(no-)?sanitize-coverage= flag values, diagnosing any invalid
  76 /// components. Returns OR of members of \c CoverageFeature enumeration.
  77 static int parseCoverageFeatures(const Driver &D, const llvm::opt::Arg *A);
  78
  79 /// Produce an argument string from ArgList \p Args, which shows how it
  80 /// provides some sanitizer kind from \p Mask. For example, the argument list
  81 /// "-fsanitize=thread,vptr -fsanitize=address" with mask \c NeedsUbsanRt
  82 /// would produce "-fsanitize=vptr".
  83 static std::string lastArgumentForMask(const Driver &D,
  84                                        const llvm::opt::ArgList &Args,
  85                                        SanitizerMask Mask);
  86
  87 /// Produce an argument string from argument \p A, which shows how it provides
  88 /// a value in \p Mask. For instance, the argument
  89 /// "-fsanitize=address,alignment" with mask \c NeedsUbsanRt would produce
  90 /// "-fsanitize=alignment".
  91 static std::string describeSanitizeArg(const llvm::opt::Arg *A,
  92                                        SanitizerMask Mask);
  93
  94 /// Produce a string containing comma-separated names of sanitizers in \p
  95 /// Sanitizers set.
  96 static std::string toString(const clang::SanitizerSet &Sanitizers);
  97
  98 static void addDefaultBlacklists(const Driver &D, SanitizerMask Kinds,
  99                                  std::vector<std::string> &BlacklistFiles) {
 100   struct Blacklist {
 101     const char *File;
 102     SanitizerMask Mask;
 103   } Blacklists[] = {{"asan_blacklist.txt", Address},
 104                     {"hwasan_blacklist.txt", HWAddress},
 105                     {"msan_blacklist.txt", Memory},
 106                     {"tsan_blacklist.txt", Thread},
 107                     {"dfsan_abilist.txt", DataFlow},
 108                     {"cfi_blacklist.txt", CFI},
 109                     {"ubsan_blacklist.txt", Undefined | Integer | Nullability}};
 110
 111   for (auto BL : Blacklists) {
 112     if (!(Kinds & BL.Mask))
 113       continue;
 114
 115     clang::SmallString<64> Path(D.ResourceDir);
 116     llvm::sys::path::append(Path, "share", BL.File);
 117     if (llvm::sys::fs::exists(Path))
 118       BlacklistFiles.push_back(Path.str());
 119     else if (BL.Mask == CFI)
 120       // If cfi_blacklist.txt cannot be found in the resource dir, driver
 121       // should fail.
 122       D.Diag(clang::diag::err_drv_no_such_file) << Path;
 123   }
 124 }
 125
 126 /// Sets group bits for every group that has at least one representative already
 127 /// enabled in \p Kinds.
 128 static SanitizerMask setGroupBits(SanitizerMask Kinds) {
 129 #define SANITIZER(NAME, ID)
 130 #define SANITIZER_GROUP(NAME, ID, ALIAS)                                       \
 131   if (Kinds & SanitizerKind::ID)                                               \
 132     Kinds |= SanitizerKind::ID##Group;
 133 #include "clang/Basic/Sanitizers.def"
 134   return Kinds;
 135 }
 136
 137 static SanitizerMask parseSanitizeTrapArgs(const Driver &D,
 138                                            const llvm::opt::ArgList &Args) {
 139   SanitizerMask TrapRemove = 0; // During the loop below, the accumulated set of
 140                                 // sanitizers disabled by the current sanitizer
 141                                 // argument or any argument after it.
 142   SanitizerMask TrappingKinds = 0;
 143   SanitizerMask TrappingSupportedWithGroups = setGroupBits(TrappingSupported);
 144
 145   for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
 146        I != E; ++I) {
 147     const auto *Arg = *I;
 148     if (Arg->getOption().matches(options::OPT_fsanitize_trap_EQ)) {
 149       Arg->claim();
 150       SanitizerMask Add = parseArgValues(D, Arg, true);
 151       Add &= ~TrapRemove;
 152       if (SanitizerMask InvalidValues = Add & ~TrappingSupportedWithGroups) {
 153         SanitizerSet S;
 154         S.Mask = InvalidValues;
 155         D.Diag(diag::err_drv_unsupported_option_argument) << "-fsanitize-trap"
 156                                                           << toString(S);
 157       }
 158       TrappingKinds |= expandSanitizerGroups(Add) & ~TrapRemove;
 159     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_trap_EQ)) {
 160       Arg->claim();
 161       TrapRemove |= expandSanitizerGroups(parseArgValues(D, Arg, true));
 162     } else if (Arg->getOption().matches(
 163                    options::OPT_fsanitize_undefined_trap_on_error)) {
 164       Arg->claim();
 165       TrappingKinds |=
 166           expandSanitizerGroups(UndefinedGroup & ~TrapRemove) & ~TrapRemove;
 167     } else if (Arg->getOption().matches(
 168                    options::OPT_fno_sanitize_undefined_trap_on_error)) {
 169       Arg->claim();
 170       TrapRemove |= expandSanitizerGroups(UndefinedGroup);
 171     }
 172   }
 173
 174   // Apply default trapping behavior.
 175   TrappingKinds |= TrappingDefault & ~TrapRemove;
 176
 177   return TrappingKinds;
 178 }
 179
 180 bool SanitizerArgs::needsUbsanRt() const {
 181   // All of these include ubsan.
 182   if (needsAsanRt() || needsMsanRt() || needsHwasanRt() || needsTsanRt() ||
 183       needsDfsanRt() || needsLsanRt() || needsCfiDiagRt() ||
 184       (needsScudoRt() && !requiresMinimalRuntime()))
 185     return false;
 186
 187   return (Sanitizers.Mask & NeedsUbsanRt & ~TrapSanitizers.Mask) ||
 188          CoverageFeatures;
 189 }
 190
 191 bool SanitizerArgs::needsCfiRt() const {
 192   return !(Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso &&
 193          !ImplicitCfiRuntime;
 194 }
 195
 196 bool SanitizerArgs::needsCfiDiagRt() const {
 197   return (Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso &&
 198          !ImplicitCfiRuntime;
 199 }
 200
 201 bool SanitizerArgs::requiresPIE() const {
 202   return NeedPIE || (Sanitizers.Mask & RequiresPIE);
 203 }
 204
 205 bool SanitizerArgs::needsUnwindTables() const {
 206   return Sanitizers.Mask & NeedsUnwindTables;
 207 }
 208
 209 SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 210                              const llvm::opt::ArgList &Args) {
 211   SanitizerMask AllRemove = 0;  // During the loop below, the accumulated set of
 212                                 // sanitizers disabled by the current sanitizer
 213                                 // argument or any argument after it.
 214   SanitizerMask AllAddedKinds = 0;  // Mask of all sanitizers ever enabled by
 215                                     // -fsanitize= flags (directly or via group
 216                                     // expansion), some of which may be disabled
 217                                     // later. Used to carefully prune
 218                                     // unused-argument diagnostics.
 219   SanitizerMask DiagnosedKinds = 0;  // All Kinds we have diagnosed up to now.
 220                                      // Used to deduplicate diagnostics.
 221   SanitizerMask Kinds = 0;
 222   const SanitizerMask Supported = setGroupBits(TC.getSupportedSanitizers());
 223
 224   CfiCrossDso = Args.hasFlag(options::OPT_fsanitize_cfi_cross_dso,
 225                              options::OPT_fno_sanitize_cfi_cross_dso, false);
 226
 227   ToolChain::RTTIMode RTTIMode = TC.getRTTIMode();
 228
 229   const Driver &D = TC.getDriver();
 230   SanitizerMask TrappingKinds = parseSanitizeTrapArgs(D, Args);
 231   SanitizerMask InvalidTrappingKinds = TrappingKinds & NotAllowedWithTrap;
 232
 233   MinimalRuntime =
 234       Args.hasFlag(options::OPT_fsanitize_minimal_runtime,
 235                    options::OPT_fno_sanitize_minimal_runtime, MinimalRuntime);
 236
 237   // The object size sanitizer should not be enabled at -O0.
 238   Arg *OptLevel = Args.getLastArg(options::OPT_O_Group);
 239   bool RemoveObjectSizeAtO0 =
 240       !OptLevel || OptLevel->getOption().matches(options::OPT_O0);
 241
 242   for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
 243        I != E; ++I) {
 244     const auto *Arg = *I;
 245     if (Arg->getOption().matches(options::OPT_fsanitize_EQ)) {
 246       Arg->claim();
 247       SanitizerMask Add = parseArgValues(D, Arg, /*AllowGroups=*/true);
 248
 249       if (RemoveObjectSizeAtO0) {
 250         AllRemove |= SanitizerKind::ObjectSize;
 251
 252         // The user explicitly enabled the object size sanitizer. Warn that
 253         // that this does nothing at -O0.
 254         if (Add & SanitizerKind::ObjectSize)
 255           D.Diag(diag::warn_drv_object_size_disabled_O0)
 256               << Arg->getAsString(Args);
 257       }
 258
 259       AllAddedKinds |= expandSanitizerGroups(Add);
 260
 261       // Avoid diagnosing any sanitizer which is disabled later.
 262       Add &= ~AllRemove;
 263       // At this point we have not expanded groups, so any unsupported
 264       // sanitizers in Add are those which have been explicitly enabled.
 265       // Diagnose them.
 266       if (SanitizerMask KindsToDiagnose =
 267               Add & InvalidTrappingKinds & ~DiagnosedKinds) {
 268         std::string Desc = describeSanitizeArg(*I, KindsToDiagnose);
 269         D.Diag(diag::err_drv_argument_not_allowed_with)
 270             << Desc << "-fsanitize-trap=undefined";
 271         DiagnosedKinds |= KindsToDiagnose;
 272       }
 273       Add &= ~InvalidTrappingKinds;
 274
 275       if (MinimalRuntime) {
 276         if (SanitizerMask KindsToDiagnose =
 277                 Add & NotAllowedWithMinimalRuntime & ~DiagnosedKinds) {
 278           std::string Desc = describeSanitizeArg(*I, KindsToDiagnose);
 279           D.Diag(diag::err_drv_argument_not_allowed_with)
 280               << Desc << "-fsanitize-minimal-runtime";
 281           DiagnosedKinds |= KindsToDiagnose;
 282         }
 283         Add &= ~NotAllowedWithMinimalRuntime;
 284       }
 285
 286       // FIXME: Make CFI on member function calls compatible with cross-DSO CFI.
 287       // There are currently two problems:
 288       // - Virtual function call checks need to pass a pointer to the function
 289       //   address to llvm.type.test and a pointer to the address point to the
 290       //   diagnostic function. Currently we pass the same pointer to both
 291       //   places.
 292       // - Non-virtual function call checks may need to check multiple type
 293       //   identifiers.
 294       // Fixing both of those may require changes to the cross-DSO CFI
 295       // interface.
 296       if (CfiCrossDso && (Add & CFIMFCall & ~DiagnosedKinds)) {
 297         D.Diag(diag::err_drv_argument_not_allowed_with)
 298             << "-fsanitize=cfi-mfcall"
 299             << "-fsanitize-cfi-cross-dso";
 300         Add &= ~CFIMFCall;
 301         DiagnosedKinds |= CFIMFCall;
 302       }
 303
 304       if (SanitizerMask KindsToDiagnose = Add & ~Supported & ~DiagnosedKinds) {
 305         std::string Desc = describeSanitizeArg(*I, KindsToDiagnose);
 306         D.Diag(diag::err_drv_unsupported_opt_for_target)
 307             << Desc << TC.getTriple().str();
 308         DiagnosedKinds |= KindsToDiagnose;
 309       }
 310       Add &= Supported;
 311
 312       // Test for -fno-rtti + explicit -fsanitizer=vptr before expanding groups
 313       // so we don't error out if -fno-rtti and -fsanitize=undefined were
 314       // passed.
 315       if ((Add & Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
 316         if (const llvm::opt::Arg *NoRTTIArg = TC.getRTTIArg()) {
 317           assert(NoRTTIArg->getOption().matches(options::OPT_fno_rtti) &&
 318                   "RTTI disabled without -fno-rtti option?");
 319           // The user explicitly passed -fno-rtti with -fsanitize=vptr, but
 320           // the vptr sanitizer requires RTTI, so this is a user error.
 321           D.Diag(diag::err_drv_argument_not_allowed_with)
 322               << "-fsanitize=vptr" << NoRTTIArg->getAsString(Args);
 323         } else {
 324           // The vptr sanitizer requires RTTI, but RTTI is disabled (by
 325           // default). Warn that the vptr sanitizer is being disabled.
 326           D.Diag(diag::warn_drv_disabling_vptr_no_rtti_default);
 327         }
 328
 329         // Take out the Vptr sanitizer from the enabled sanitizers
 330         AllRemove |= Vptr;
 331       }
 332
 333       Add = expandSanitizerGroups(Add);
 334       // Group expansion may have enabled a sanitizer which is disabled later.
 335       Add &= ~AllRemove;
 336       // Silently discard any unsupported sanitizers implicitly enabled through
 337       // group expansion.
 338       Add &= ~InvalidTrappingKinds;
 339       if (MinimalRuntime) {
 340         Add &= ~NotAllowedWithMinimalRuntime;
 341       }
 342       if (CfiCrossDso)
 343         Add &= ~CFIMFCall;
 344       Add &= Supported;
 345
 346       if (Add & Fuzzer)
 347         Add |= FuzzerNoLink;
 348
 349       // Enable coverage if the fuzzing flag is set.
 350       if (Add & FuzzerNoLink) {
 351         CoverageFeatures |= CoverageInline8bitCounters | CoverageIndirCall |
 352                             CoverageTraceCmp | CoveragePCTable;
 353         // Due to TLS differences, stack depth tracking is only enabled on Linux
 354         if (TC.getTriple().isOSLinux())
 355           CoverageFeatures |= CoverageStackDepth;
 356       }
 357
 358       Kinds |= Add;
 359     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_EQ)) {
 360       Arg->claim();
 361       SanitizerMask Remove = parseArgValues(D, Arg, true);
 362       AllRemove |= expandSanitizerGroups(Remove);
 363     }
 364   }
 365
 366   std::pair<SanitizerMask, SanitizerMask> IncompatibleGroups[] = {
 367       std::make_pair(Address, Thread | Memory),
 368       std::make_pair(Thread, Memory),
 369       std::make_pair(Leak, Thread | Memory),
 370       std::make_pair(KernelAddress, Address | Leak | Thread | Memory),
 371       std::make_pair(HWAddress, Address | Thread | Memory | KernelAddress),
 372       std::make_pair(Efficiency, Address | HWAddress | Leak | Thread | Memory |
 373                                      KernelAddress),
 374       std::make_pair(Scudo, Address | HWAddress | Leak | Thread | Memory |
 375                                 KernelAddress | Efficiency),
 376       std::make_pair(SafeStack, Address | HWAddress | Leak | Thread | Memory |
 377                                     KernelAddress | Efficiency),
 378       std::make_pair(ShadowCallStack, Address | HWAddress | Leak | Thread |
 379                                           Memory | KernelAddress | Efficiency |
 380                                           SafeStack),
 381       std::make_pair(KernelHWAddress, Address | HWAddress | Leak | Thread |
 382                                           Memory | KernelAddress | Efficiency |
 383                                           SafeStack | ShadowCallStack)};
 384
 385   // Enable toolchain specific default sanitizers if not explicitly disabled.
 386   SanitizerMask Default = TC.getDefaultSanitizers() & ~AllRemove;
 387
 388   // Disable default sanitizers that are incompatible with explicitly requested
 389   // ones.
 390   for (auto G : IncompatibleGroups) {
 391     SanitizerMask Group = G.first;
 392     if ((Default & Group) && (Kinds & G.second))
 393       Default &= ~Group;
 394   }
 395
 396   Kinds |= Default;
 397
 398   // We disable the vptr sanitizer if it was enabled by group expansion but RTTI
 399   // is disabled.
 400   if ((Kinds & Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
 401     Kinds &= ~Vptr;
 402   }
 403
 404   // Check that LTO is enabled if we need it.
 405   if ((Kinds & NeedsLTO) && !D.isUsingLTO()) {
 406     D.Diag(diag::err_drv_argument_only_allowed_with)
 407         << lastArgumentForMask(D, Args, Kinds & NeedsLTO) << "-flto";
 408   }
 409
 410   if ((Kinds & ShadowCallStack) &&
 411       TC.getTriple().getArch() == llvm::Triple::aarch64 &&
 412       !llvm::AArch64::isX18ReservedByDefault(TC.getTriple()) &&
 413       !Args.hasArg(options::OPT_ffixed_x18)) {
 414     D.Diag(diag::err_drv_argument_only_allowed_with)
 415         << lastArgumentForMask(D, Args, Kinds & ShadowCallStack)
 416         << "-ffixed-x18";
 417   }
 418
 419   // Report error if there are non-trapping sanitizers that require
 420   // c++abi-specific  parts of UBSan runtime, and they are not provided by the
 421   // toolchain. We don't have a good way to check the latter, so we just
 422   // check if the toolchan supports vptr.
 423   if (~Supported & Vptr) {
 424     SanitizerMask KindsToDiagnose = Kinds & ~TrappingKinds & NeedsUbsanCxxRt;
 425     // The runtime library supports the Microsoft C++ ABI, but only well enough
 426     // for CFI. FIXME: Remove this once we support vptr on Windows.
 427     if (TC.getTriple().isOSWindows())
 428       KindsToDiagnose &= ~CFI;
 429     if (KindsToDiagnose) {
 430       SanitizerSet S;
 431       S.Mask = KindsToDiagnose;
 432       D.Diag(diag::err_drv_unsupported_opt_for_target)
 433           << ("-fno-sanitize-trap=" + toString(S)) << TC.getTriple().str();
 434       Kinds &= ~KindsToDiagnose;
 435     }
 436   }
 437
 438   // Warn about incompatible groups of sanitizers.
 439   for (auto G : IncompatibleGroups) {
 440     SanitizerMask Group = G.first;
 441     if (Kinds & Group) {
 442       if (SanitizerMask Incompatible = Kinds & G.second) {
 443         D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 444             << lastArgumentForMask(D, Args, Group)
 445             << lastArgumentForMask(D, Args, Incompatible);
 446         Kinds &= ~Incompatible;
 447       }
 448     }
 449   }
 450   // FIXME: Currently -fsanitize=leak is silently ignored in the presence of
 451   // -fsanitize=address. Perhaps it should print an error, or perhaps
 452   // -f(-no)sanitize=leak should change whether leak detection is enabled by
 453   // default in ASan?
 454
 455   // Parse -f(no-)?sanitize-recover flags.
 456   SanitizerMask RecoverableKinds = RecoverableByDefault | AlwaysRecoverable;
 457   SanitizerMask DiagnosedUnrecoverableKinds = 0;
 458   SanitizerMask DiagnosedAlwaysRecoverableKinds = 0;
 459   for (const auto *Arg : Args) {
 460     const char *DeprecatedReplacement = nullptr;
 461     if (Arg->getOption().matches(options::OPT_fsanitize_recover)) {
 462       DeprecatedReplacement =
 463           "-fsanitize-recover=undefined,integer' or '-fsanitize-recover=all";
 464       RecoverableKinds |= expandSanitizerGroups(LegacyFsanitizeRecoverMask);
 465       Arg->claim();
 466     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_recover)) {
 467       DeprecatedReplacement = "-fno-sanitize-recover=undefined,integer' or "
 468                               "'-fno-sanitize-recover=all";
 469       RecoverableKinds &= ~expandSanitizerGroups(LegacyFsanitizeRecoverMask);
 470       Arg->claim();
 471     } else if (Arg->getOption().matches(options::OPT_fsanitize_recover_EQ)) {
 472       SanitizerMask Add = parseArgValues(D, Arg, true);
 473       // Report error if user explicitly tries to recover from unrecoverable
 474       // sanitizer.
 475       if (SanitizerMask KindsToDiagnose =
 476               Add & Unrecoverable & ~DiagnosedUnrecoverableKinds) {
 477         SanitizerSet SetToDiagnose;
 478         SetToDiagnose.Mask |= KindsToDiagnose;
 479         D.Diag(diag::err_drv_unsupported_option_argument)
 480             << Arg->getOption().getName() << toString(SetToDiagnose);
 481         DiagnosedUnrecoverableKinds |= KindsToDiagnose;
 482       }
 483       RecoverableKinds |= expandSanitizerGroups(Add);
 484       Arg->claim();
 485     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_recover_EQ)) {
 486       SanitizerMask Remove = parseArgValues(D, Arg, true);
 487       // Report error if user explicitly tries to disable recovery from
 488       // always recoverable sanitizer.
 489       if (SanitizerMask KindsToDiagnose =
 490               Remove & AlwaysRecoverable & ~DiagnosedAlwaysRecoverableKinds) {
 491         SanitizerSet SetToDiagnose;
 492         SetToDiagnose.Mask |= KindsToDiagnose;
 493         D.Diag(diag::err_drv_unsupported_option_argument)
 494             << Arg->getOption().getName() << toString(SetToDiagnose);
 495         DiagnosedAlwaysRecoverableKinds |= KindsToDiagnose;
 496       }
 497       RecoverableKinds &= ~expandSanitizerGroups(Remove);
 498       Arg->claim();
 499     }
 500     if (DeprecatedReplacement) {
 501       D.Diag(diag::warn_drv_deprecated_arg) << Arg->getAsString(Args)
 502                                             << DeprecatedReplacement;
 503     }
 504   }
 505   RecoverableKinds &= Kinds;
 506   RecoverableKinds &= ~Unrecoverable;
 507
 508   TrappingKinds &= Kinds;
 509   RecoverableKinds &= ~TrappingKinds;
 510
 511   // Setup blacklist files.
 512   // Add default blacklist from resource directory.
 513   addDefaultBlacklists(D, Kinds, BlacklistFiles);
 514   // Parse -f(no-)sanitize-blacklist options.
 515   for (const auto *Arg : Args) {
 516     if (Arg->getOption().matches(options::OPT_fsanitize_blacklist)) {
 517       Arg->claim();
 518       std::string BLPath = Arg->getValue();
 519       if (llvm::sys::fs::exists(BLPath)) {
 520         BlacklistFiles.push_back(BLPath);
 521         ExtraDeps.push_back(BLPath);
 522       } else {
 523         D.Diag(clang::diag::err_drv_no_such_file) << BLPath;
 524       }
 525     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_blacklist)) {
 526       Arg->claim();
 527       BlacklistFiles.clear();
 528       ExtraDeps.clear();
 529     }
 530   }
 531   // Validate blacklists format.
 532   {
 533     std::string BLError;
 534     std::unique_ptr<llvm::SpecialCaseList> SCL(
 535         llvm::SpecialCaseList::create(BlacklistFiles, BLError));
 536     if (!SCL.get())
 537       D.Diag(clang::diag::err_drv_malformed_sanitizer_blacklist) << BLError;
 538   }
 539
 540   // Parse -f[no-]sanitize-memory-track-origins[=level] options.
 541   if (AllAddedKinds & Memory) {
 542     if (Arg *A =
 543             Args.getLastArg(options::OPT_fsanitize_memory_track_origins_EQ,
 544                             options::OPT_fsanitize_memory_track_origins,
 545                             options::OPT_fno_sanitize_memory_track_origins)) {
 546       if (A->getOption().matches(options::OPT_fsanitize_memory_track_origins)) {
 547         MsanTrackOrigins = 2;
 548       } else if (A->getOption().matches(
 549                      options::OPT_fno_sanitize_memory_track_origins)) {
 550         MsanTrackOrigins = 0;
 551       } else {
 552         StringRef S = A->getValue();
 553         if (S.getAsInteger(0, MsanTrackOrigins) || MsanTrackOrigins < 0 ||
 554             MsanTrackOrigins > 2) {
 555           D.Diag(clang::diag::err_drv_invalid_value) << A->getAsString(Args) << S;
 556         }
 557       }
 558     }
 559     MsanUseAfterDtor =
 560         Args.hasFlag(options::OPT_fsanitize_memory_use_after_dtor,
 561                      options::OPT_fno_sanitize_memory_use_after_dtor,
 562                      MsanUseAfterDtor);
 563     NeedPIE |= !(TC.getTriple().isOSLinux() &&
 564                  TC.getTriple().getArch() == llvm::Triple::x86_64);
 565   } else {
 566     MsanUseAfterDtor = false;
 567   }
 568
 569   if (AllAddedKinds & Thread) {
 570     TsanMemoryAccess = Args.hasFlag(options::OPT_fsanitize_thread_memory_access,
 571                                     options::OPT_fno_sanitize_thread_memory_access,
 572                                     TsanMemoryAccess);
 573     TsanFuncEntryExit = Args.hasFlag(options::OPT_fsanitize_thread_func_entry_exit,
 574                                      options::OPT_fno_sanitize_thread_func_entry_exit,
 575                                      TsanFuncEntryExit);
 576     TsanAtomics = Args.hasFlag(options::OPT_fsanitize_thread_atomics,
 577                                options::OPT_fno_sanitize_thread_atomics,
 578                                TsanAtomics);
 579   }
 580
 581   if (AllAddedKinds & CFI) {
 582     // Without PIE, external function address may resolve to a PLT record, which
 583     // can not be verified by the target module.
 584     NeedPIE |= CfiCrossDso;
 585     CfiICallGeneralizePointers =
 586         Args.hasArg(options::OPT_fsanitize_cfi_icall_generalize_pointers);
 587
 588     if (CfiCrossDso && CfiICallGeneralizePointers)
 589       D.Diag(diag::err_drv_argument_not_allowed_with)
 590           << "-fsanitize-cfi-cross-dso"
 591           << "-fsanitize-cfi-icall-generalize-pointers";
 592   }
 593
 594   Stats = Args.hasFlag(options::OPT_fsanitize_stats,
 595                        options::OPT_fno_sanitize_stats, false);
 596
 597   if (MinimalRuntime) {
 598     SanitizerMask IncompatibleMask =
 599         Kinds & ~setGroupBits(CompatibleWithMinimalRuntime);
 600     if (IncompatibleMask)
 601       D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 602           << "-fsanitize-minimal-runtime"
 603           << lastArgumentForMask(D, Args, IncompatibleMask);
 604
 605     SanitizerMask NonTrappingCfi = Kinds & CFI & ~TrappingKinds;
 606     if (NonTrappingCfi)
 607       D.Diag(clang::diag::err_drv_argument_only_allowed_with)
 608           << "fsanitize-minimal-runtime"
 609           << "fsanitize-trap=cfi";
 610   }
 611
 612   // Parse -f(no-)?sanitize-coverage flags if coverage is supported by the
 613   // enabled sanitizers.
 614   for (const auto *Arg : Args) {
 615     if (Arg->getOption().matches(options::OPT_fsanitize_coverage)) {
 616       int LegacySanitizeCoverage;
 617       if (Arg->getNumValues() == 1 &&
 618           !StringRef(Arg->getValue(0))
 619                .getAsInteger(0, LegacySanitizeCoverage)) {
 620         CoverageFeatures = 0;
 621         Arg->claim();
 622         if (LegacySanitizeCoverage != 0) {
 623           D.Diag(diag::warn_drv_deprecated_arg)
 624               << Arg->getAsString(Args) << "-fsanitize-coverage=trace-pc-guard";
 625         }
 626         continue;
 627       }
 628       CoverageFeatures |= parseCoverageFeatures(D, Arg);
 629
 630       // Disable coverage and not claim the flags if there is at least one
 631       // non-supporting sanitizer.
 632       if (!(AllAddedKinds & ~AllRemove & ~setGroupBits(SupportsCoverage))) {
 633         Arg->claim();
 634       } else {
 635         CoverageFeatures = 0;
 636       }
 637     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_coverage)) {
 638       Arg->claim();
 639       CoverageFeatures &= ~parseCoverageFeatures(D, Arg);
 640     }
 641   }
 642   // Choose at most one coverage type: function, bb, or edge.
 643   if ((CoverageFeatures & CoverageFunc) && (CoverageFeatures & CoverageBB))
 644     D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 645         << "-fsanitize-coverage=func"
 646         << "-fsanitize-coverage=bb";
 647   if ((CoverageFeatures & CoverageFunc) && (CoverageFeatures & CoverageEdge))
 648     D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 649         << "-fsanitize-coverage=func"
 650         << "-fsanitize-coverage=edge";
 651   if ((CoverageFeatures & CoverageBB) && (CoverageFeatures & CoverageEdge))
 652     D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 653         << "-fsanitize-coverage=bb"
 654         << "-fsanitize-coverage=edge";
 655   // Basic block tracing and 8-bit counters require some type of coverage
 656   // enabled.
 657   if (CoverageFeatures & CoverageTraceBB)
 658     D.Diag(clang::diag::warn_drv_deprecated_arg)
 659         << "-fsanitize-coverage=trace-bb"
 660         << "-fsanitize-coverage=trace-pc-guard";
 661   if (CoverageFeatures & Coverage8bitCounters)
 662     D.Diag(clang::diag::warn_drv_deprecated_arg)
 663         << "-fsanitize-coverage=8bit-counters"
 664         << "-fsanitize-coverage=trace-pc-guard";
 665
 666   int InsertionPointTypes = CoverageFunc | CoverageBB | CoverageEdge;
 667   int InstrumentationTypes =
 668       CoverageTracePC | CoverageTracePCGuard | CoverageInline8bitCounters;
 669   if ((CoverageFeatures & InsertionPointTypes) &&
 670       !(CoverageFeatures & InstrumentationTypes)) {
 671     D.Diag(clang::diag::warn_drv_deprecated_arg)
 672         << "-fsanitize-coverage=[func|bb|edge]"
 673         << "-fsanitize-coverage=[func|bb|edge],[trace-pc-guard|trace-pc]";
 674   }
 675
 676   // trace-pc w/o func/bb/edge implies edge.
 677   if (!(CoverageFeatures & InsertionPointTypes)) {
 678     if (CoverageFeatures &
 679         (CoverageTracePC | CoverageTracePCGuard | CoverageInline8bitCounters))
 680       CoverageFeatures |= CoverageEdge;
 681
 682     if (CoverageFeatures & CoverageStackDepth)
 683       CoverageFeatures |= CoverageFunc;
 684   }
 685
 686   SharedRuntime =
 687       Args.hasFlag(options::OPT_shared_libsan, options::OPT_static_libsan,
 688                    TC.getTriple().isAndroid() || TC.getTriple().isOSFuchsia() ||
 689                        TC.getTriple().isOSDarwin());
 690
 691   ImplicitCfiRuntime = TC.getTriple().isAndroid();
 692
 693   if (AllAddedKinds & Address) {
 694     NeedPIE |= TC.getTriple().isOSFuchsia();
 695     if (Arg *A =
 696             Args.getLastArg(options::OPT_fsanitize_address_field_padding)) {
 697         StringRef S = A->getValue();
 698         // Legal values are 0 and 1, 2, but in future we may add more levels.
 699         if (S.getAsInteger(0, AsanFieldPadding) || AsanFieldPadding < 0 ||
 700             AsanFieldPadding > 2) {
 701           D.Diag(clang::diag::err_drv_invalid_value) << A->getAsString(Args) << S;
 702         }
 703     }
 704
 705     if (Arg *WindowsDebugRTArg =
 706             Args.getLastArg(options::OPT__SLASH_MTd, options::OPT__SLASH_MT,
 707                             options::OPT__SLASH_MDd, options::OPT__SLASH_MD,
 708                             options::OPT__SLASH_LDd, options::OPT__SLASH_LD)) {
 709       switch (WindowsDebugRTArg->getOption().getID()) {
 710       case options::OPT__SLASH_MTd:
 711       case options::OPT__SLASH_MDd:
 712       case options::OPT__SLASH_LDd:
 713         D.Diag(clang::diag::err_drv_argument_not_allowed_with)
 714             << WindowsDebugRTArg->getAsString(Args)
 715             << lastArgumentForMask(D, Args, Address);
 716         D.Diag(clang::diag::note_drv_address_sanitizer_debug_runtime);
 717       }
 718     }
 719
 720     AsanUseAfterScope = Args.hasFlag(
 721         options::OPT_fsanitize_address_use_after_scope,
 722         options::OPT_fno_sanitize_address_use_after_scope, AsanUseAfterScope);
 723
 724     // As a workaround for a bug in gold 2.26 and earlier, dead stripping of
 725     // globals in ASan is disabled by default on ELF targets.
 726     // See https://sourceware.org/bugzilla/show_bug.cgi?id=19002
 727     AsanGlobalsDeadStripping =
 728         !TC.getTriple().isOSBinFormatELF() || TC.getTriple().isOSFuchsia() ||
 729         Args.hasArg(options::OPT_fsanitize_address_globals_dead_stripping);
 730   } else {
 731     AsanUseAfterScope = false;
 732   }
 733
 734   if (AllAddedKinds & SafeStack) {
 735     // SafeStack runtime is built into the system on Fuchsia.
 736     SafeStackRuntime = !TC.getTriple().isOSFuchsia();
 737   }
 738
 739   // Parse -link-cxx-sanitizer flag.
 740   LinkCXXRuntimes =
 741       Args.hasArg(options::OPT_fsanitize_link_cxx_runtime) || D.CCCIsCXX();
 742
 743   // Finally, initialize the set of available and recoverable sanitizers.
 744   Sanitizers.Mask |= Kinds;
 745   RecoverableSanitizers.Mask |= RecoverableKinds;
 746   TrapSanitizers.Mask |= TrappingKinds;
 747   assert(!(RecoverableKinds & TrappingKinds) &&
 748          "Overlap between recoverable and trapping sanitizers");
 749 }
 750
 751 static std::string toString(const clang::SanitizerSet &Sanitizers) {
 752   std::string Res;
 753 #define SANITIZER(NAME, ID)                                                    \
 754   if (Sanitizers.has(ID)) {                                                    \
 755     if (!Res.empty())                                                          \
 756       Res += ",";                                                              \
 757     Res += NAME;                                                               \
 758   }
 759 #include "clang/Basic/Sanitizers.def"
 760   return Res;
 761 }
 762
 763 static void addIncludeLinkerOption(const ToolChain &TC,
 764                                    const llvm::opt::ArgList &Args,
 765                                    llvm::opt::ArgStringList &CmdArgs,
 766                                    StringRef SymbolName) {
 767   SmallString<64> LinkerOptionFlag;
 768   LinkerOptionFlag = "--linker-option=/include:";
 769   if (TC.getTriple().getArch() == llvm::Triple::x86) {
 770     // Win32 mangles C function names with a '_' prefix.
 771     LinkerOptionFlag += '_';
 772   }
 773   LinkerOptionFlag += SymbolName;
 774   CmdArgs.push_back(Args.MakeArgString(LinkerOptionFlag));
 775 }
 776
 777 void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
 778                             llvm::opt::ArgStringList &CmdArgs,
 779                             types::ID InputType) const {
 780   // NVPTX doesn't currently support sanitizers.  Bailing out here means that
 781   // e.g. -fsanitize=address applies only to host code, which is what we want
 782   // for now.
 783   if (TC.getTriple().isNVPTX())
 784     return;
 785
 786   // Translate available CoverageFeatures to corresponding clang-cc1 flags.
 787   // Do it even if Sanitizers.empty() since some forms of coverage don't require
 788   // sanitizers.
 789   std::pair<int, const char *> CoverageFlags[] = {
 790     std::make_pair(CoverageFunc, "-fsanitize-coverage-type=1"),
 791     std::make_pair(CoverageBB, "-fsanitize-coverage-type=2"),
 792     std::make_pair(CoverageEdge, "-fsanitize-coverage-type=3"),
 793     std::make_pair(CoverageIndirCall, "-fsanitize-coverage-indirect-calls"),
 794     std::make_pair(CoverageTraceBB, "-fsanitize-coverage-trace-bb"),
 795     std::make_pair(CoverageTraceCmp, "-fsanitize-coverage-trace-cmp"),
 796     std::make_pair(CoverageTraceDiv, "-fsanitize-coverage-trace-div"),
 797     std::make_pair(CoverageTraceGep, "-fsanitize-coverage-trace-gep"),
 798     std::make_pair(Coverage8bitCounters, "-fsanitize-coverage-8bit-counters"),
 799     std::make_pair(CoverageTracePC, "-fsanitize-coverage-trace-pc"),
 800     std::make_pair(CoverageTracePCGuard, "-fsanitize-coverage-trace-pc-guard"),
 801     std::make_pair(CoverageInline8bitCounters, "-fsanitize-coverage-inline-8bit-counters"),
 802     std::make_pair(CoveragePCTable, "-fsanitize-coverage-pc-table"),
 803     std::make_pair(CoverageNoPrune, "-fsanitize-coverage-no-prune"),
 804     std::make_pair(CoverageStackDepth, "-fsanitize-coverage-stack-depth")};
 805   for (auto F : CoverageFlags) {
 806     if (CoverageFeatures & F.first)
 807       CmdArgs.push_back(F.second);
 808   }
 809
 810   if (TC.getTriple().isOSWindows() && needsUbsanRt()) {
 811     // Instruct the code generator to embed linker directives in the object file
 812     // that cause the required runtime libraries to be linked.
 813     CmdArgs.push_back(Args.MakeArgString(
 814         "--dependent-lib=" + TC.getCompilerRT(Args, "ubsan_standalone")));
 815     if (types::isCXX(InputType))
 816       CmdArgs.push_back(Args.MakeArgString(
 817           "--dependent-lib=" + TC.getCompilerRT(Args, "ubsan_standalone_cxx")));
 818   }
 819   if (TC.getTriple().isOSWindows() && needsStatsRt()) {
 820     CmdArgs.push_back(Args.MakeArgString("--dependent-lib=" +
 821                                          TC.getCompilerRT(Args, "stats_client")));
 822
 823     // The main executable must export the stats runtime.
 824     // FIXME: Only exporting from the main executable (e.g. based on whether the
 825     // translation unit defines main()) would save a little space, but having
 826     // multiple copies of the runtime shouldn't hurt.
 827     CmdArgs.push_back(Args.MakeArgString("--dependent-lib=" +
 828                                          TC.getCompilerRT(Args, "stats")));
 829     addIncludeLinkerOption(TC, Args, CmdArgs, "__sanitizer_stats_register");
 830   }
 831
 832   if (Sanitizers.empty())
 833     return;
 834   CmdArgs.push_back(Args.MakeArgString("-fsanitize=" + toString(Sanitizers)));
 835
 836   if (!RecoverableSanitizers.empty())
 837     CmdArgs.push_back(Args.MakeArgString("-fsanitize-recover=" +
 838                                          toString(RecoverableSanitizers)));
 839
 840   if (!TrapSanitizers.empty())
 841     CmdArgs.push_back(
 842         Args.MakeArgString("-fsanitize-trap=" + toString(TrapSanitizers)));
 843
 844   for (const auto &BLPath : BlacklistFiles) {
 845     SmallString<64> BlacklistOpt("-fsanitize-blacklist=");
 846     BlacklistOpt += BLPath;
 847     CmdArgs.push_back(Args.MakeArgString(BlacklistOpt));
 848   }
 849   for (const auto &Dep : ExtraDeps) {
 850     SmallString<64> ExtraDepOpt("-fdepfile-entry=");
 851     ExtraDepOpt += Dep;
 852     CmdArgs.push_back(Args.MakeArgString(ExtraDepOpt));
 853   }
 854
 855   if (MsanTrackOrigins)
 856     CmdArgs.push_back(Args.MakeArgString("-fsanitize-memory-track-origins=" +
 857                                          Twine(MsanTrackOrigins)));
 858
 859   if (MsanUseAfterDtor)
 860     CmdArgs.push_back("-fsanitize-memory-use-after-dtor");
 861
 862   // FIXME: Pass these parameters as function attributes, not as -llvm flags.
 863   if (!TsanMemoryAccess) {
 864     CmdArgs.push_back("-mllvm");
 865     CmdArgs.push_back("-tsan-instrument-memory-accesses=0");
 866     CmdArgs.push_back("-mllvm");
 867     CmdArgs.push_back("-tsan-instrument-memintrinsics=0");
 868   }
 869   if (!TsanFuncEntryExit) {
 870     CmdArgs.push_back("-mllvm");
 871     CmdArgs.push_back("-tsan-instrument-func-entry-exit=0");
 872   }
 873   if (!TsanAtomics) {
 874     CmdArgs.push_back("-mllvm");
 875     CmdArgs.push_back("-tsan-instrument-atomics=0");
 876   }
 877
 878   if (CfiCrossDso)
 879     CmdArgs.push_back("-fsanitize-cfi-cross-dso");
 880
 881   if (CfiICallGeneralizePointers)
 882     CmdArgs.push_back("-fsanitize-cfi-icall-generalize-pointers");
 883
 884   if (Stats)
 885     CmdArgs.push_back("-fsanitize-stats");
 886
 887   if (MinimalRuntime)
 888     CmdArgs.push_back("-fsanitize-minimal-runtime");
 889
 890   if (AsanFieldPadding)
 891     CmdArgs.push_back(Args.MakeArgString("-fsanitize-address-field-padding=" +
 892                                          Twine(AsanFieldPadding)));
 893
 894   if (AsanUseAfterScope)
 895     CmdArgs.push_back("-fsanitize-address-use-after-scope");
 896
 897   if (AsanGlobalsDeadStripping)
 898     CmdArgs.push_back("-fsanitize-address-globals-dead-stripping");
 899
 900   // MSan: Workaround for PR16386.
 901   // ASan: This is mainly to help LSan with cases such as
 902   // https://github.com/google/sanitizers/issues/373
 903   // We can't make this conditional on -fsanitize=leak, as that flag shouldn't
 904   // affect compilation.
 905   if (Sanitizers.has(Memory) || Sanitizers.has(Address))
 906     CmdArgs.push_back("-fno-assume-sane-operator-new");
 907
 908   // Require -fvisibility= flag on non-Windows when compiling if vptr CFI is
 909   // enabled.
 910   if (Sanitizers.hasOneOf(CFIClasses) && !TC.getTriple().isOSWindows() &&
 911       !Args.hasArg(options::OPT_fvisibility_EQ)) {
 912     TC.getDriver().Diag(clang::diag::err_drv_argument_only_allowed_with)
 913         << lastArgumentForMask(TC.getDriver(), Args,
 914                                Sanitizers.Mask & CFIClasses)
 915         << "-fvisibility=";
 916   }
 917 }
 918
 919 SanitizerMask parseArgValues(const Driver &D, const llvm::opt::Arg *A,
 920                              bool DiagnoseErrors) {
 921   assert((A->getOption().matches(options::OPT_fsanitize_EQ) ||
 922           A->getOption().matches(options::OPT_fno_sanitize_EQ) ||
 923           A->getOption().matches(options::OPT_fsanitize_recover_EQ) ||
 924           A->getOption().matches(options::OPT_fno_sanitize_recover_EQ) ||
 925           A->getOption().matches(options::OPT_fsanitize_trap_EQ) ||
 926           A->getOption().matches(options::OPT_fno_sanitize_trap_EQ)) &&
 927          "Invalid argument in parseArgValues!");
 928   SanitizerMask Kinds = 0;
 929   for (int i = 0, n = A->getNumValues(); i != n; ++i) {
 930     const char *Value = A->getValue(i);
 931     SanitizerMask Kind;
 932     // Special case: don't accept -fsanitize=all.
 933     if (A->getOption().matches(options::OPT_fsanitize_EQ) &&
 934         0 == strcmp("all", Value))
 935       Kind = 0;
 936     // Similarly, don't accept -fsanitize=efficiency-all.
 937     else if (A->getOption().matches(options::OPT_fsanitize_EQ) &&
 938         0 == strcmp("efficiency-all", Value))
 939       Kind = 0;
 940     else
 941       Kind = parseSanitizerValue(Value, /*AllowGroups=*/true);
 942
 943     if (Kind)
 944       Kinds |= Kind;
 945     else if (DiagnoseErrors)
 946       D.Diag(clang::diag::err_drv_unsupported_option_argument)
 947           << A->getOption().getName() << Value;
 948   }
 949   return Kinds;
 950 }
 951
 952 int parseCoverageFeatures(const Driver &D, const llvm::opt::Arg *A) {
 953   assert(A->getOption().matches(options::OPT_fsanitize_coverage) ||
 954          A->getOption().matches(options::OPT_fno_sanitize_coverage));
 955   int Features = 0;
 956   for (int i = 0, n = A->getNumValues(); i != n; ++i) {
 957     const char *Value = A->getValue(i);
 958     int F = llvm::StringSwitch<int>(Value)
 959         .Case("func", CoverageFunc)
 960         .Case("bb", CoverageBB)
 961         .Case("edge", CoverageEdge)
 962         .Case("indirect-calls", CoverageIndirCall)
 963         .Case("trace-bb", CoverageTraceBB)
 964         .Case("trace-cmp", CoverageTraceCmp)
 965         .Case("trace-div", CoverageTraceDiv)
 966         .Case("trace-gep", CoverageTraceGep)
 967         .Case("8bit-counters", Coverage8bitCounters)
 968         .Case("trace-pc", CoverageTracePC)
 969         .Case("trace-pc-guard", CoverageTracePCGuard)
 970         .Case("no-prune", CoverageNoPrune)
 971         .Case("inline-8bit-counters", CoverageInline8bitCounters)
 972         .Case("pc-table", CoveragePCTable)
 973         .Case("stack-depth", CoverageStackDepth)
 974         .Default(0);
 975     if (F == 0)
 976       D.Diag(clang::diag::err_drv_unsupported_option_argument)
 977           << A->getOption().getName() << Value;
 978     Features |= F;
 979   }
 980   return Features;
 981 }
 982
 983 std::string lastArgumentForMask(const Driver &D, const llvm::opt::ArgList &Args,
 984                                 SanitizerMask Mask) {
 985   for (llvm::opt::ArgList::const_reverse_iterator I = Args.rbegin(),
 986                                                   E = Args.rend();
 987        I != E; ++I) {
 988     const auto *Arg = *I;
 989     if (Arg->getOption().matches(options::OPT_fsanitize_EQ)) {
 990       SanitizerMask AddKinds =
 991           expandSanitizerGroups(parseArgValues(D, Arg, false));
 992       if (AddKinds & Mask)
 993         return describeSanitizeArg(Arg, Mask);
 994     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_EQ)) {
 995       SanitizerMask RemoveKinds =
 996           expandSanitizerGroups(parseArgValues(D, Arg, false));
 997       Mask &= ~RemoveKinds;
 998     }
 999   }
1000   llvm_unreachable("arg list didn't provide expected value");
1001 }
1002
1003 std::string describeSanitizeArg(const llvm::opt::Arg *A, SanitizerMask Mask) {
1004   assert(A->getOption().matches(options::OPT_fsanitize_EQ)
1005          && "Invalid argument in describeSanitizerArg!");
1006
1007   std::string Sanitizers;
1008   for (int i = 0, n = A->getNumValues(); i != n; ++i) {
1009     if (expandSanitizerGroups(
1010             parseSanitizerValue(A->getValue(i), /*AllowGroups=*/true)) &
1011         Mask) {
1012       if (!Sanitizers.empty())
1013         Sanitizers += ",";
1014       Sanitizers += A->getValue(i);
1015     }
1016   }
1017
1018   assert(!Sanitizers.empty() && "arg didn't provide expected value");
1019   return "-fsanitize=" + Sanitizers;
1020 }