[Driver] Allow enum SanitizerOrdinal to represent more than 64 different sanitizer checks, NFC.

enum SanitizerOrdinal has reached maximum capacity, this change extends the capacity to 128 sanitizer checks.
This can eventually allow us to add gcc 8's options "-fsanitize=pointer-substract" and "-fsanitize=pointer-compare".

Fixes: https://llvm.org/PR39425

Differential Revision: https://reviews.llvm.org/D57914


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@354873 91177308-0d34-0410-b5e6-96231b3b80d8

11 files changed, 325 insertions, 145 deletions

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index faad45db35..bf226c824d 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -2366,7 +2366,7 @@ def NoSanitize : InheritableAttr {
   let Documentation = [NoSanitizeDocs];
   let AdditionalMembers = [{
     SanitizerMask getMask() const {
-      SanitizerMask Mask = 0;
+      SanitizerMask Mask;
       for (auto SanitizerName : sanitizers()) {
         SanitizerMask ParsedMask =
             parseSanitizerValue(SanitizerName, /*AllowGroups=*/true);
diff --git a/include/clang/Basic/Sanitizers.def b/include/clang/Basic/Sanitizers.def
index 34bd6fc5f0..98e9aaa5b8 100644
--- a/include/clang/Basic/Sanitizers.def
+++ b/include/clang/Basic/Sanitizers.def
@@ -177,7 +177,7 @@ SANITIZER("scudo", Scudo)
 
 // Magic group, containing all sanitizers. For example, "-fno-sanitize=all"
 // can be used to disable all the sanitizers.
-SANITIZER_GROUP("all", All, ~0ULL)
+SANITIZER_GROUP("all", All, ~SanitizerMask())
 
 #undef SANITIZER
 #undef SANITIZER_GROUP
diff --git a/include/clang/Basic/Sanitizers.h b/include/clang/Basic/Sanitizers.h
index f2cfadbee0..afbdf63840 100644
--- a/include/clang/Basic/Sanitizers.h
+++ b/include/clang/Basic/Sanitizers.h
@@ -21,44 +21,167 @@
 #include <cstdint>
 
 namespace clang {
+class SanitizerMask;
+}
 
-using SanitizerMask = uint64_t;
+namespace llvm {
+class hashcode;
+hash_code hash_value(const clang::SanitizerMask &Arg);
+} // namespace llvm
 
-namespace SanitizerKind {
+namespace clang {
 
-// Assign ordinals to possible values of -fsanitize= flag, which we will use as
-// bit positions.
-enum SanitizerOrdinal : uint64_t {
-#define SANITIZER(NAME, ID) SO_##ID,
-#define SANITIZER_GROUP(NAME, ID, ALIAS) SO_##ID##Group,
-#include "clang/Basic/Sanitizers.def"
-  SO_Count
+class SanitizerMask {
+  /// Number of array elements.
+  static constexpr unsigned kNumElem = 2;
+  /// Mask value initialized to 0.
+  uint64_t maskLoToHigh[kNumElem]{};
+  /// Number of bits in a mask.
+  static constexpr unsigned kNumBits = sizeof(decltype(maskLoToHigh)) * 8;
+  /// Number of bits in a mask element.
+  static constexpr unsigned kNumBitElem = sizeof(decltype(maskLoToHigh[0])) * 8;
+
+public:
+  static constexpr bool checkBitPos(const unsigned Pos) {
+    return Pos < kNumBits;
+  }
+
+  /// Create a mask with a bit enabled at position Pos.
+  static SanitizerMask bitPosToMask(const unsigned Pos) {
+    assert(Pos < kNumBits && "Bit position too big.");
+    SanitizerMask mask;
+    mask.maskLoToHigh[Pos / kNumBitElem] = 1ULL << Pos % kNumBitElem;
+    return mask;
+  }
+
+  unsigned countPopulation() const {
+    unsigned total = 0;
+    for (const auto &Val : maskLoToHigh)
+      total += llvm::countPopulation(Val);
+    return total;
+  }
+
+  void flipAllBits() {
+    for (auto &Val : maskLoToHigh)
+      Val = ~Val;
+  }
+
+  bool isPowerOf2() const {
+    return countPopulation() == 1;
+  }
+
+  llvm::hash_code hash_value() const;
+
+  explicit operator bool() const {
+    for (const auto &Val : maskLoToHigh)
+      if (Val)
+        return true;
+    return false;
+  };
+
+  bool operator==(const SanitizerMask &V) const {
+    for (unsigned k = 0; k < kNumElem; k++) {
+      if (maskLoToHigh[k] != V.maskLoToHigh[k])
+        return false;
+    }
+    return true;
+  }
+
+  SanitizerMask &operator&=(const SanitizerMask &RHS) {
+    for (unsigned k = 0; k < kNumElem; k++)
+      maskLoToHigh[k] &= RHS.maskLoToHigh[k];
+    return *this;
+  }
+
+  SanitizerMask &operator|=(const SanitizerMask &RHS) {
+    for (unsigned k = 0; k < kNumElem; k++)
+      maskLoToHigh[k] |= RHS.maskLoToHigh[k];
+    return *this;
+  }
+
+  bool operator!() const {
+    for (const auto &Val : maskLoToHigh)
+      if (Val)
+        return false;
+    return true;
+  }
+
+  bool operator!=(const SanitizerMask &RHS) const { return !((*this) == RHS); }
 };
 
+inline SanitizerMask operator~(SanitizerMask v) {
+  v.flipAllBits();
+  return v;
+}
+
+inline SanitizerMask operator&(SanitizerMask a, const SanitizerMask &b) {
+  a &= b;
+  return a;
+}
+
+inline SanitizerMask operator|(SanitizerMask a, const SanitizerMask &b) {
+  a |= b;
+  return a;
+}
+
 // Define the set of sanitizer kinds, as well as the set of sanitizers each
 // sanitizer group expands into.
-#define SANITIZER(NAME, ID) \
-  const SanitizerMask ID = 1ULL << SO_##ID;
-#define SANITIZER_GROUP(NAME, ID, ALIAS) \
-  const SanitizerMask ID = ALIAS; \
-  const SanitizerMask ID##Group = 1ULL << SO_##ID##Group;
+// Uses static data member of a class template as recommended in second
+// workaround from n4424 to avoid odr issues.
+// FIXME: Can be marked as constexpr once c++14 can be used in llvm.
+// FIXME: n4424 workaround can be replaced by c++17 inline variable.
+template <typename T = void> struct SanitizerMasks {
+
+  // Assign ordinals to possible values of -fsanitize= flag, which we will use
+  // as bit positions.
+  enum SanitizerOrdinal : uint64_t {
+#define SANITIZER(NAME, ID) SO_##ID,
+#define SANITIZER_GROUP(NAME, ID, ALIAS) SO_##ID##Group,
+#include "clang/Basic/Sanitizers.def"
+    SO_Count
+  };
+
+#define SANITIZER(NAME, ID)                                                    \
+  static const SanitizerMask ID;                                               \
+  static_assert(SanitizerMask::checkBitPos(SO_##ID), "Bit position too big.");
+#define SANITIZER_GROUP(NAME, ID, ALIAS)                                       \
+  static const SanitizerMask ID;                                               \
+  static const SanitizerMask ID##Group;                                        \
+  static_assert(SanitizerMask::checkBitPos(SO_##ID##Group),                    \
+                "Bit position too big.");
 #include "clang/Basic/Sanitizers.def"
+}; // SanitizerMasks
+
+#define SANITIZER(NAME, ID)                                                    \
+  template <typename T>                                                        \
+  const SanitizerMask SanitizerMasks<T>::ID =                                  \
+      SanitizerMask::bitPosToMask(SO_##ID);
+#define SANITIZER_GROUP(NAME, ID, ALIAS)                                       \
+  template <typename T>                                                        \
+  const SanitizerMask SanitizerMasks<T>::ID = SanitizerMask(ALIAS);            \
+  template <typename T>                                                        \
+  const SanitizerMask SanitizerMasks<T>::ID##Group =                           \
+      SanitizerMask::bitPosToMask(SO_##ID##Group);
+#include "clang/Basic/Sanitizers.def"
+
+// Explicit instantiation here to ensure correct initialization order.
+template struct SanitizerMasks<>;
 
-} // namespace SanitizerKind
+using SanitizerKind = SanitizerMasks<>;
 
 struct SanitizerSet {
   /// Check if a certain (single) sanitizer is enabled.
   bool has(SanitizerMask K) const {
-    assert(llvm::isPowerOf2_64(K));
-    return Mask & K;
+    assert(K.isPowerOf2() && "Has to be a single sanitizer.");
+    return static_cast<bool>(Mask & K);
   }
 
   /// Check if one or more sanitizers are enabled.
-  bool hasOneOf(SanitizerMask K) const { return Mask & K; }
+  bool hasOneOf(SanitizerMask K) const { return static_cast<bool>(Mask & K); }
 
   /// Enable or disable a certain (single) sanitizer.
   void set(SanitizerMask K, bool Value) {
-    assert(llvm::isPowerOf2_64(K));
+    assert(K.isPowerOf2() && "Has to be a single sanitizer.");
     Mask = Value ? (Mask | K) : (Mask & ~K);
   }
 
@@ -66,10 +189,10 @@ struct SanitizerSet {
   void clear(SanitizerMask K = SanitizerKind::All) { Mask &= ~K; }
 
   /// Returns true if no sanitizers are enabled.
-  bool empty() const { return Mask == 0; }
+  bool empty() const { return !Mask; }
 
   /// Bitmask of enabled sanitizers.
-  SanitizerMask Mask = 0;
+  SanitizerMask Mask;
 };
 
 /// Parse a single value from a -fsanitize= or -fno-sanitize= value list.
diff --git a/include/clang/Driver/ToolChain.h b/include/clang/Driver/ToolChain.h
index e82675d334..014b23843a 100644
--- a/include/clang/Driver/ToolChain.h
+++ b/include/clang/Driver/ToolChain.h
@@ -565,7 +565,9 @@ public:
   virtual SanitizerMask getSupportedSanitizers() const;
 
   /// Return sanitizers which are enabled by default.
-  virtual SanitizerMask getDefaultSanitizers() const { return 0; }
+  virtual SanitizerMask getDefaultSanitizers() const {
+    return SanitizerMask();
+  }
 };
 
 /// Set a ToolChain's effective triple. Reset it when the registration object
diff --git a/lib/Basic/SanitizerSpecialCaseList.cpp b/lib/Basic/SanitizerSpecialCaseList.cpp
index e042db92b4..5fb0f9660b 100644
--- a/lib/Basic/SanitizerSpecialCaseList.cpp
+++ b/lib/Basic/SanitizerSpecialCaseList.cpp
@@ -36,7 +36,7 @@ SanitizerSpecialCaseList::createOrDie(const std::vector<std::string> &Paths) {
 
 void SanitizerSpecialCaseList::createSanitizerSections() {
   for (auto &S : Sections) {
-    SanitizerMask Mask = 0;
+    SanitizerMask Mask;
 
 #define SANITIZER(NAME, ID)                                                    \
   if (S.SectionMatcher->match(NAME))                                           \
diff --git a/lib/Basic/Sanitizers.cpp b/lib/Basic/Sanitizers.cpp
index dd0fddbdc7..6203c1ac77 100644
--- a/lib/Basic/Sanitizers.cpp
+++ b/lib/Basic/Sanitizers.cpp
@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/Sanitizers.h"
+#include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringSwitch.h"
 
 using namespace clang;
@@ -19,9 +20,9 @@ SanitizerMask clang::parseSanitizerValue(StringRef Value, bool AllowGroups) {
   SanitizerMask ParsedKind = llvm::StringSwitch<SanitizerMask>(Value)
 #define SANITIZER(NAME, ID) .Case(NAME, SanitizerKind::ID)
 #define SANITIZER_GROUP(NAME, ID, ALIAS)                                       \
-  .Case(NAME, AllowGroups ? SanitizerKind::ID##Group : 0)
+  .Case(NAME, AllowGroups ? SanitizerKind::ID##Group : SanitizerMask())
 #include "clang/Basic/Sanitizers.def"
-    .Default(0);
+    .Default(SanitizerMask());
   return ParsedKind;
 }
 
@@ -33,3 +34,13 @@ SanitizerMask clang::expandSanitizerGroups(SanitizerMask Kinds) {
 #include "clang/Basic/Sanitizers.def"
   return Kinds;
 }
+
+llvm::hash_code SanitizerMask::hash_value() const {
+  return llvm::hash_combine_range(&maskLoToHigh[0], &maskLoToHigh[kNumElem]);
+}
+
+namespace llvm {
+hash_code hash_value(const clang::SanitizerMask &Arg) {
+  return Arg.hash_value();
+}
+} // namespace llvm
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 5ee0378efe..09ba2a0eb7 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -2855,16 +2855,13 @@ enum class CheckRecoverableKind {
 }
 
 static CheckRecoverableKind getRecoverableKind(SanitizerMask Kind) {
-  assert(llvm::countPopulation(Kind) == 1);
-  switch (Kind) {
-  case SanitizerKind::Vptr:
+  assert(Kind.countPopulation() == 1);
+  if (Kind == SanitizerKind::Vptr)
     return CheckRecoverableKind::AlwaysRecoverable;
-  case SanitizerKind::Return:
-  case SanitizerKind::Unreachable:
+  else if (Kind == SanitizerKind::Return || Kind == SanitizerKind::Unreachable)
     return CheckRecoverableKind::Unrecoverable;
-  default:
+  else
     return CheckRecoverableKind::Recoverable;
-  }
 }
 
 namespace {
diff --git a/lib/Driver/SanitizerArgs.cpp b/lib/Driver/SanitizerArgs.cpp
index 0112416a88..e84933bea0 100644
--- a/lib/Driver/SanitizerArgs.cpp
+++ b/lib/Driver/SanitizerArgs.cpp
@@ -21,33 +21,52 @@
 #include <memory>
 
 using namespace clang;
-using namespace clang::SanitizerKind;
 using namespace clang::driver;
 using namespace llvm::opt;
 
-enum : SanitizerMask {
-  NeedsUbsanRt = Undefined | Integer | ImplicitConversion | Nullability | CFI,
-  NeedsUbsanCxxRt = Vptr | CFI,
-  NotAllowedWithTrap = Vptr,
-  NotAllowedWithMinimalRuntime = Vptr,
-  RequiresPIE = DataFlow | HWAddress | Scudo,
-  NeedsUnwindTables = Address | HWAddress | Thread | Memory | DataFlow,
-  SupportsCoverage = Address | HWAddress | KernelAddress | KernelHWAddress |
-                     Memory | KernelMemory | Leak | Undefined | Integer |
-                     ImplicitConversion | Nullability | DataFlow | Fuzzer |
-                     FuzzerNoLink,
-  RecoverableByDefault = Undefined | Integer | ImplicitConversion | Nullability,
-  Unrecoverable = Unreachable | Return,
-  AlwaysRecoverable = KernelAddress | KernelHWAddress,
-  LegacyFsanitizeRecoverMask = Undefined | Integer,
-  NeedsLTO = CFI,
-  TrappingSupported = (Undefined & ~Vptr) | UnsignedIntegerOverflow |
-                      ImplicitConversion | Nullability | LocalBounds | CFI,
-  TrappingDefault = CFI,
-  CFIClasses =
-      CFIVCall | CFINVCall | CFIMFCall | CFIDerivedCast | CFIUnrelatedCast,
-  CompatibleWithMinimalRuntime = TrappingSupported | Scudo | ShadowCallStack,
-};
+static const SanitizerMask NeedsUbsanRt =
+    SanitizerKind::Undefined | SanitizerKind::Integer |
+    SanitizerKind::ImplicitConversion | SanitizerKind::Nullability |
+    SanitizerKind::CFI;
+static const SanitizerMask NeedsUbsanCxxRt =
+    SanitizerKind::Vptr | SanitizerKind::CFI;
+static const SanitizerMask NotAllowedWithTrap = SanitizerKind::Vptr;
+static const SanitizerMask NotAllowedWithMinimalRuntime = SanitizerKind::Vptr;
+static const SanitizerMask RequiresPIE =
+    SanitizerKind::DataFlow | SanitizerKind::HWAddress | SanitizerKind::Scudo;
+static const SanitizerMask NeedsUnwindTables =
+    SanitizerKind::Address | SanitizerKind::HWAddress | SanitizerKind::Thread |
+    SanitizerKind::Memory | SanitizerKind::DataFlow;
+static const SanitizerMask SupportsCoverage =
+    SanitizerKind::Address | SanitizerKind::HWAddress |
+    SanitizerKind::KernelAddress | SanitizerKind::KernelHWAddress |
+    SanitizerKind::Memory | SanitizerKind::KernelMemory | SanitizerKind::Leak |
+    SanitizerKind::Undefined | SanitizerKind::Integer |
+    SanitizerKind::ImplicitConversion | SanitizerKind::Nullability |
+    SanitizerKind::DataFlow | SanitizerKind::Fuzzer |
+    SanitizerKind::FuzzerNoLink;
+static const SanitizerMask RecoverableByDefault =
+    SanitizerKind::Undefined | SanitizerKind::Integer |
+    SanitizerKind::ImplicitConversion | SanitizerKind::Nullability;
+static const SanitizerMask Unrecoverable =
+    SanitizerKind::Unreachable | SanitizerKind::Return;
+static const SanitizerMask AlwaysRecoverable =
+    SanitizerKind::KernelAddress | SanitizerKind::KernelHWAddress;
+static const SanitizerMask LegacyFsanitizeRecoverMask =
+    SanitizerKind::Undefined | SanitizerKind::Integer;
+static const SanitizerMask NeedsLTO = SanitizerKind::CFI;
+static const SanitizerMask TrappingSupported =
+    (SanitizerKind::Undefined & ~SanitizerKind::Vptr) |
+    SanitizerKind::UnsignedIntegerOverflow | SanitizerKind::ImplicitConversion |
+    SanitizerKind::Nullability | SanitizerKind::LocalBounds |
+    SanitizerKind::CFI;
+static const SanitizerMask TrappingDefault = SanitizerKind::CFI;
+static const SanitizerMask CFIClasses =
+    SanitizerKind::CFIVCall | SanitizerKind::CFINVCall |
+    SanitizerKind::CFIMFCall | SanitizerKind::CFIDerivedCast |
+    SanitizerKind::CFIUnrelatedCast;
+static const SanitizerMask CompatibleWithMinimalRuntime =
+    TrappingSupported | SanitizerKind::Scudo | SanitizerKind::ShadowCallStack;
 
 enum CoverageFeature {
   CoverageFunc = 1 << 0,
@@ -100,13 +119,15 @@ static void addDefaultBlacklists(const Driver &D, SanitizerMask Kinds,
   struct Blacklist {
     const char *File;
     SanitizerMask Mask;
-  } Blacklists[] = {{"asan_blacklist.txt", Address},
-                    {"hwasan_blacklist.txt", HWAddress},
-                    {"msan_blacklist.txt", Memory},
-                    {"tsan_blacklist.txt", Thread},
-                    {"dfsan_abilist.txt", DataFlow},
-                    {"cfi_blacklist.txt", CFI},
-                    {"ubsan_blacklist.txt", Undefined | Integer | Nullability}};
+  } Blacklists[] = {{"asan_blacklist.txt", SanitizerKind::Address},
+                    {"hwasan_blacklist.txt", SanitizerKind::HWAddress},
+                    {"msan_blacklist.txt", SanitizerKind::Memory},
+                    {"tsan_blacklist.txt", SanitizerKind::Thread},
+                    {"dfsan_abilist.txt", SanitizerKind::DataFlow},
+                    {"cfi_blacklist.txt", SanitizerKind::CFI},
+                    {"ubsan_blacklist.txt", SanitizerKind::Undefined |
+                                                SanitizerKind::Integer |
+                                                SanitizerKind::Nullability}};
 
   for (auto BL : Blacklists) {
     if (!(Kinds & BL.Mask))
@@ -116,7 +137,7 @@ static void addDefaultBlacklists(const Driver &D, SanitizerMask Kinds,
     llvm::sys::path::append(Path, "share", BL.File);
     if (llvm::sys::fs::exists(Path))
       BlacklistFiles.push_back(Path.str());
-    else if (BL.Mask == CFI)
+    else if (BL.Mask == SanitizerKind::CFI)
       // If cfi_blacklist.txt cannot be found in the resource dir, driver
       // should fail.
       D.Diag(clang::diag::err_drv_no_such_file) << Path;
@@ -136,10 +157,10 @@ static SanitizerMask setGroupBits(SanitizerMask Kinds) {
 
 static SanitizerMask parseSanitizeTrapArgs(const Driver &D,
                                            const llvm::opt::ArgList &Args) {
-  SanitizerMask TrapRemove = 0; // During the loop below, the accumulated set of
+  SanitizerMask TrapRemove;     // During the loop below, the accumulated set of
                                 // sanitizers disabled by the current sanitizer
                                 // argument or any argument after it.
-  SanitizerMask TrappingKinds = 0;
+  SanitizerMask TrappingKinds;
   SanitizerMask TrappingSupportedWithGroups = setGroupBits(TrappingSupported);
 
   for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
@@ -163,11 +184,12 @@ static SanitizerMask parseSanitizeTrapArgs(const Driver &D,
                    options::OPT_fsanitize_undefined_trap_on_error)) {
       Arg->claim();
       TrappingKinds |=
-          expandSanitizerGroups(UndefinedGroup & ~TrapRemove) & ~TrapRemove;
+          expandSanitizerGroups(SanitizerKind::UndefinedGroup & ~TrapRemove) &
+          ~TrapRemove;
     } else if (Arg->getOption().matches(
                    options::OPT_fno_sanitize_undefined_trap_on_error)) {
       Arg->claim();
-      TrapRemove |= expandSanitizerGroups(UndefinedGroup);
+      TrapRemove |= expandSanitizerGroups(SanitizerKind::UndefinedGroup);
     }
   }
 
@@ -189,13 +211,13 @@ bool SanitizerArgs::needsUbsanRt() const {
 }
 
 bool SanitizerArgs::needsCfiRt() const {
-  return !(Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso &&
-         !ImplicitCfiRuntime;
+  return !(Sanitizers.Mask & SanitizerKind::CFI & ~TrapSanitizers.Mask) &&
+         CfiCrossDso && !ImplicitCfiRuntime;
 }
 
 bool SanitizerArgs::needsCfiDiagRt() const {
-  return (Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso &&
-         !ImplicitCfiRuntime;
+  return (Sanitizers.Mask & SanitizerKind::CFI & ~TrapSanitizers.Mask) &&
+         CfiCrossDso && !ImplicitCfiRuntime;
 }
 
 bool SanitizerArgs::requiresPIE() const {
@@ -203,24 +225,26 @@ bool SanitizerArgs::requiresPIE() const {
 }
 
 bool SanitizerArgs::needsUnwindTables() const {
-  return Sanitizers.Mask & NeedsUnwindTables;
+  return static_cast<bool>(Sanitizers.Mask & NeedsUnwindTables);
 }
 
-bool SanitizerArgs::needsLTO() const { return Sanitizers.Mask & NeedsLTO; }
+bool SanitizerArgs::needsLTO() const {
+  return static_cast<bool>(Sanitizers.Mask & NeedsLTO);
+}
 
 SanitizerArgs::SanitizerArgs(const ToolChain &TC,
                              const llvm::opt::ArgList &Args) {
-  SanitizerMask AllRemove = 0;  // During the loop below, the accumulated set of
+  SanitizerMask AllRemove;      // During the loop below, the accumulated set of
                                 // sanitizers disabled by the current sanitizer
                                 // argument or any argument after it.
-  SanitizerMask AllAddedKinds = 0;  // Mask of all sanitizers ever enabled by
+  SanitizerMask AllAddedKinds;      // Mask of all sanitizers ever enabled by
                                     // -fsanitize= flags (directly or via group
                                     // expansion), some of which may be disabled
                                     // later. Used to carefully prune
                                     // unused-argument diagnostics.
-  SanitizerMask DiagnosedKinds = 0;  // All Kinds we have diagnosed up to now.
+  SanitizerMask DiagnosedKinds;      // All Kinds we have diagnosed up to now.
                                      // Used to deduplicate diagnostics.
-  SanitizerMask Kinds = 0;
+  SanitizerMask Kinds;
   const SanitizerMask Supported = setGroupBits(TC.getSupportedSanitizers());
 
   CfiCrossDso = Args.hasFlag(options::OPT_fsanitize_cfi_cross_dso,
@@ -295,12 +319,12 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       //   identifiers.
       // Fixing both of those may require changes to the cross-DSO CFI
       // interface.
-      if (CfiCrossDso && (Add & CFIMFCall & ~DiagnosedKinds)) {
+      if (CfiCrossDso && (Add & SanitizerKind::CFIMFCall & ~DiagnosedKinds)) {
         D.Diag(diag::err_drv_argument_not_allowed_with)
             << "-fsanitize=cfi-mfcall"
             << "-fsanitize-cfi-cross-dso";
-        Add &= ~CFIMFCall;
-        DiagnosedKinds |= CFIMFCall;
+        Add &= ~SanitizerKind::CFIMFCall;
+        DiagnosedKinds |= SanitizerKind::CFIMFCall;
       }
 
       if (SanitizerMask KindsToDiagnose = Add & ~Supported & ~DiagnosedKinds) {
@@ -314,7 +338,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       // Test for -fno-rtti + explicit -fsanitizer=vptr before expanding groups
       // so we don't error out if -fno-rtti and -fsanitize=undefined were
       // passed.
-      if ((Add & Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
+      if ((Add & SanitizerKind::Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
         if (const llvm::opt::Arg *NoRTTIArg = TC.getRTTIArg()) {
           assert(NoRTTIArg->getOption().matches(options::OPT_fno_rtti) &&
                   "RTTI disabled without -fno-rtti option?");
@@ -329,7 +353,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
         }
 
         // Take out the Vptr sanitizer from the enabled sanitizers
-        AllRemove |= Vptr;
+        AllRemove |= SanitizerKind::Vptr;
       }
 
       Add = expandSanitizerGroups(Add);
@@ -342,14 +366,14 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
         Add &= ~NotAllowedWithMinimalRuntime;
       }
       if (CfiCrossDso)
-        Add &= ~CFIMFCall;
+        Add &= ~SanitizerKind::CFIMFCall;
       Add &= Supported;
 
-      if (Add & Fuzzer)
-        Add |= FuzzerNoLink;
+      if (Add & SanitizerKind::Fuzzer)
+        Add |= SanitizerKind::FuzzerNoLink;
 
       // Enable coverage if the fuzzing flag is set.
-      if (Add & FuzzerNoLink) {
+      if (Add & SanitizerKind::FuzzerNoLink) {
         CoverageFeatures |= CoverageInline8bitCounters | CoverageIndirCall |
                             CoverageTraceCmp | CoveragePCTable;
         // Due to TLS differences, stack depth tracking is only enabled on Linux
@@ -366,23 +390,42 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   }
 
   std::pair<SanitizerMask, SanitizerMask> IncompatibleGroups[] = {
-      std::make_pair(Address, Thread | Memory),
-      std::make_pair(Thread, Memory),
-      std::make_pair(Leak, Thread | Memory),
-      std::make_pair(KernelAddress, Address | Leak | Thread | Memory),
-      std::make_pair(HWAddress, Address | Thread | Memory | KernelAddress),
-      std::make_pair(Efficiency, Address | HWAddress | Leak | Thread | Memory |
-                                     KernelAddress),
-      std::make_pair(Scudo, Address | HWAddress | Leak | Thread | Memory |
-                                KernelAddress | Efficiency),
-      std::make_pair(SafeStack, Address | HWAddress | Leak | Thread | Memory |
-                                    KernelAddress | Efficiency),
-      std::make_pair(KernelHWAddress, Address | HWAddress | Leak | Thread |
-                                          Memory | KernelAddress | Efficiency |
-                                          SafeStack),
-      std::make_pair(KernelMemory, Address | HWAddress | Leak | Thread |
-                                       Memory | KernelAddress | Efficiency |
-                                       Scudo | SafeStack)};
+      std::make_pair(SanitizerKind::Address,
+                     SanitizerKind::Thread | SanitizerKind::Memory),
+      std::make_pair(SanitizerKind::Thread, SanitizerKind::Memory),
+      std::make_pair(SanitizerKind::Leak,
+                     SanitizerKind::Thread | SanitizerKind::Memory),
+      std::make_pair(SanitizerKind::KernelAddress,
+                     SanitizerKind::Address | SanitizerKind::Leak |
+                         SanitizerKind::Thread | SanitizerKind::Memory),
+      std::make_pair(SanitizerKind::HWAddress,
+                     SanitizerKind::Address | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress),
+      std::make_pair(SanitizerKind::Efficiency,
+                     SanitizerKind::Address | SanitizerKind::HWAddress |
+                         SanitizerKind::Leak | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress),
+      std::make_pair(SanitizerKind::Scudo,
+                     SanitizerKind::Address | SanitizerKind::HWAddress |
+                         SanitizerKind::Leak | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress |
+                         SanitizerKind::Efficiency),
+      std::make_pair(SanitizerKind::SafeStack,
+                     SanitizerKind::Address | SanitizerKind::HWAddress |
+                         SanitizerKind::Leak | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress |
+                         SanitizerKind::Efficiency),
+      std::make_pair(SanitizerKind::KernelHWAddress,
+                     SanitizerKind::Address | SanitizerKind::HWAddress |
+                         SanitizerKind::Leak | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress |
+                         SanitizerKind::Efficiency | SanitizerKind::SafeStack),
+      std::make_pair(SanitizerKind::KernelMemory,
+                     SanitizerKind::Address | SanitizerKind::HWAddress |
+                         SanitizerKind::Leak | SanitizerKind::Thread |
+                         SanitizerKind::Memory | SanitizerKind::KernelAddress |
+                         SanitizerKind::Efficiency | SanitizerKind::Scudo |
+                         SanitizerKind::SafeStack)};
   // Enable toolchain specific default sanitizers if not explicitly disabled.
   SanitizerMask Default = TC.getDefaultSanitizers() & ~AllRemove;
 
@@ -398,8 +441,8 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 
   // We disable the vptr sanitizer if it was enabled by group expansion but RTTI
   // is disabled.
-  if ((Kinds & Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
-    Kinds &= ~Vptr;
+  if ((Kinds & SanitizerKind::Vptr) && (RTTIMode == ToolChain::RM_Disabled)) {
+    Kinds &= ~SanitizerKind::Vptr;
   }
 
   // Check that LTO is enabled if we need it.
@@ -408,12 +451,12 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
         << lastArgumentForMask(D, Args, Kinds & NeedsLTO) << "-flto";
   }
 
-  if ((Kinds & ShadowCallStack) &&
+  if ((Kinds & SanitizerKind::ShadowCallStack) &&
       TC.getTriple().getArch() == llvm::Triple::aarch64 &&
       !llvm::AArch64::isX18ReservedByDefault(TC.getTriple()) &&
       !Args.hasArg(options::OPT_ffixed_x18)) {
     D.Diag(diag::err_drv_argument_only_allowed_with)
-        << lastArgumentForMask(D, Args, Kinds & ShadowCallStack)
+        << lastArgumentForMask(D, Args, Kinds & SanitizerKind::ShadowCallStack)
         << "-ffixed-x18";
   }
 
@@ -421,12 +464,12 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   // c++abi-specific  parts of UBSan runtime, and they are not provided by the
   // toolchain. We don't have a good way to check the latter, so we just
   // check if the toolchan supports vptr.
-  if (~Supported & Vptr) {
+  if (~Supported & SanitizerKind::Vptr) {
     SanitizerMask KindsToDiagnose = Kinds & ~TrappingKinds & NeedsUbsanCxxRt;
     // The runtime library supports the Microsoft C++ ABI, but only well enough
     // for CFI. FIXME: Remove this once we support vptr on Windows.
     if (TC.getTriple().isOSWindows())
-      KindsToDiagnose &= ~CFI;
+      KindsToDiagnose &= ~SanitizerKind::CFI;
     if (KindsToDiagnose) {
       SanitizerSet S;
       S.Mask = KindsToDiagnose;
@@ -455,8 +498,8 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 
   // Parse -f(no-)?sanitize-recover flags.
   SanitizerMask RecoverableKinds = RecoverableByDefault | AlwaysRecoverable;
-  SanitizerMask DiagnosedUnrecoverableKinds = 0;
-  SanitizerMask DiagnosedAlwaysRecoverableKinds = 0;
+  SanitizerMask DiagnosedUnrecoverableKinds;
+  SanitizerMask DiagnosedAlwaysRecoverableKinds;
   for (const auto *Arg : Args) {
     const char *DeprecatedReplacement = nullptr;
     if (Arg->getOption().matches(options::OPT_fsanitize_recover)) {
@@ -539,7 +582,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   }
 
   // Parse -f[no-]sanitize-memory-track-origins[=level] options.
-  if (AllAddedKinds & Memory) {
+  if (AllAddedKinds & SanitizerKind::Memory) {
     if (Arg *A =
             Args.getLastArg(options::OPT_fsanitize_memory_track_origins_EQ,
                             options::OPT_fsanitize_memory_track_origins,
@@ -567,19 +610,19 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     MsanUseAfterDtor = false;
   }
 
-  if (AllAddedKinds & Thread) {
-    TsanMemoryAccess = Args.hasFlag(options::OPT_fsanitize_thread_memory_access,
-                                    options::OPT_fno_sanitize_thread_memory_access,
-                                    TsanMemoryAccess);
-    TsanFuncEntryExit = Args.hasFlag(options::OPT_fsanitize_thread_func_entry_exit,
-                                     options::OPT_fno_sanitize_thread_func_entry_exit,
-                                     TsanFuncEntryExit);
-    TsanAtomics = Args.hasFlag(options::OPT_fsanitize_thread_atomics,
-                               options::OPT_fno_sanitize_thread_atomics,
-                               TsanAtomics);
+  if (AllAddedKinds & SanitizerKind::Thread) {
+    TsanMemoryAccess = Args.hasFlag(
+        options::OPT_fsanitize_thread_memory_access,
+        options::OPT_fno_sanitize_thread_memory_access, TsanMemoryAccess);
+    TsanFuncEntryExit = Args.hasFlag(
+        options::OPT_fsanitize_thread_func_entry_exit,
+        options::OPT_fno_sanitize_thread_func_entry_exit, TsanFuncEntryExit);
+    TsanAtomics =
+        Args.hasFlag(options::OPT_fsanitize_thread_atomics,
+                     options::OPT_fno_sanitize_thread_atomics, TsanAtomics);
   }
 
-  if (AllAddedKinds & CFI) {
+  if (AllAddedKinds & SanitizerKind::CFI) {
     // Without PIE, external function address may resolve to a PLT record, which
     // can not be verified by the target module.
     NeedPIE |= CfiCrossDso;
@@ -603,7 +646,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
           << "-fsanitize-minimal-runtime"
           << lastArgumentForMask(D, Args, IncompatibleMask);
 
-    SanitizerMask NonTrappingCfi = Kinds & CFI & ~TrappingKinds;
+    SanitizerMask NonTrappingCfi = Kinds & SanitizerKind::CFI & ~TrappingKinds;
     if (NonTrappingCfi)
       D.Diag(clang::diag::err_drv_argument_only_allowed_with)
           << "fsanitize-minimal-runtime"
@@ -691,7 +734,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 
   ImplicitCfiRuntime = TC.getTriple().isAndroid();
 
-  if (AllAddedKinds & Address) {
+  if (AllAddedKinds & SanitizerKind::Address) {
     NeedPIE |= TC.getTriple().isOSFuchsia();
     if (Arg *A =
             Args.getLastArg(options::OPT_fsanitize_address_field_padding)) {
@@ -713,7 +756,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       case options::OPT__SLASH_LDd:
         D.Diag(clang::diag::err_drv_argument_not_allowed_with)
             << WindowsDebugRTArg->getAsString(Args)
-            << lastArgumentForMask(D, Args, Address);
+            << lastArgumentForMask(D, Args, SanitizerKind::Address);
         D.Diag(clang::diag::note_drv_address_sanitizer_debug_runtime);
       }
     }
@@ -742,7 +785,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     AsanUseAfterScope = false;
   }
 
-  if (AllAddedKinds & HWAddress) {
+  if (AllAddedKinds & SanitizerKind::HWAddress) {
     if (Arg *HwasanAbiArg =
             Args.getLastArg(options::OPT_fsanitize_hwaddress_abi_EQ)) {
       HwasanAbi = HwasanAbiArg->getValue();
@@ -754,7 +797,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     }
   }
 
-  if (AllAddedKinds & SafeStack) {
+  if (AllAddedKinds & SanitizerKind::SafeStack) {
     // SafeStack runtime is built into the system on Fuchsia.
     SafeStackRuntime = !TC.getTriple().isOSFuchsia();
   }
@@ -774,7 +817,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 static std::string toString(const clang::SanitizerSet &Sanitizers) {
   std::string Res;
 #define SANITIZER(NAME, ID)                                                    \
-  if (Sanitizers.has(ID)) {                                                    \
+  if (Sanitizers.has(SanitizerKind::ID)) {                                     \
     if (!Res.empty())                                                          \
       Res += ",";                                                              \
     Res += NAME;                                                               \
@@ -936,7 +979,8 @@ void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
   // https://github.com/google/sanitizers/issues/373
   // We can't make this conditional on -fsanitize=leak, as that flag shouldn't
   // affect compilation.
-  if (Sanitizers.has(Memory) || Sanitizers.has(Address))
+  if (Sanitizers.has(SanitizerKind::Memory) ||
+      Sanitizers.has(SanitizerKind::Address))
     CmdArgs.push_back("-fno-assume-sane-operator-new");
 
   // Require -fvisibility= flag on non-Windows when compiling if vptr CFI is
@@ -959,18 +1003,18 @@ SanitizerMask parseArgValues(const Driver &D, const llvm::opt::Arg *A,
           A->getOption().matches(options::OPT_fsanitize_trap_EQ) ||
           A->getOption().matches(options::OPT_fno_sanitize_trap_EQ)) &&
          "Invalid argument in parseArgValues!");
-  SanitizerMask Kinds = 0;
+  SanitizerMask Kinds;
   for (int i = 0, n = A->getNumValues(); i != n; ++i) {
     const char *Value = A->getValue(i);
     SanitizerMask Kind;
     // Special case: don't accept -fsanitize=all.
     if (A->getOption().matches(options::OPT_fsanitize_EQ) &&
         0 == strcmp("all", Value))
-      Kind = 0;
+      Kind = SanitizerMask();
     // Similarly, don't accept -fsanitize=efficiency-all.
     else if (A->getOption().matches(options::OPT_fsanitize_EQ) &&
         0 == strcmp("efficiency-all", Value))
-      Kind = 0;
+      Kind = SanitizerMask();
     else
       Kind = parseSanitizerValue(Value, /*AllowGroups=*/true);
 
diff --git a/lib/Driver/ToolChain.cpp b/lib/Driver/ToolChain.cpp
index fcf373e9f7..289d47d394 100644
--- a/lib/Driver/ToolChain.cpp
+++ b/lib/Driver/ToolChain.cpp
@@ -818,21 +818,23 @@ SanitizerMask ToolChain::getSupportedSanitizers() const {
   // Return sanitizers which don't require runtime support and are not
   // platform dependent.
 
-  using namespace SanitizerKind;
-
-  SanitizerMask Res = (Undefined & ~Vptr & ~Function) | (CFI & ~CFIICall) |
-                      CFICastStrict | UnsignedIntegerOverflow |
-                      ImplicitConversion | Nullability | LocalBounds;
+  SanitizerMask Res = (SanitizerKind::Undefined & ~SanitizerKind::Vptr &
+                       ~SanitizerKind::Function) |
+                      (SanitizerKind::CFI & ~SanitizerKind::CFIICall) |
+                      SanitizerKind::CFICastStrict |
+                      SanitizerKind::UnsignedIntegerOverflow |
+                      SanitizerKind::ImplicitConversion |
+                      SanitizerKind::Nullability | SanitizerKind::LocalBounds;
   if (getTriple().getArch() == llvm::Triple::x86 ||
       getTriple().getArch() == llvm::Triple::x86_64 ||
       getTriple().getArch() == llvm::Triple::arm ||
       getTriple().getArch() == llvm::Triple::aarch64 ||
       getTriple().getArch() == llvm::Triple::wasm32 ||
       getTriple().getArch() == llvm::Triple::wasm64)
-    Res |= CFIICall;
+    Res |= SanitizerKind::CFIICall;
   if (getTriple().getArch() == llvm::Triple::x86_64 ||
       getTriple().getArch() == llvm::Triple::aarch64)
-    Res |= ShadowCallStack;
+    Res |= SanitizerKind::ShadowCallStack;
   return Res;
 }
 
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index b1a886241a..4d061c6b6c 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -551,7 +551,7 @@ static void parseSanitizerKinds(StringRef FlagName,
                                 DiagnosticsEngine &Diags, SanitizerSet &S) {
   for (const auto &Sanitizer : Sanitizers) {
     SanitizerMask K = parseSanitizerValue(Sanitizer, /*AllowGroups=*/false);
-    if (K == 0)
+    if (K == SanitizerMask())
       Diags.Report(diag::err_drv_invalid_value) << FlagName << Sanitizer;
     else
       S.set(K, true);
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index bf11ae98bc..d312936ebc 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -6211,7 +6211,8 @@ static void handleNoSanitizeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     if (!S.checkStringLiteralArgumentAttr(AL, I, SanitizerName, &LiteralLoc))
       return;
 
-    if (parseSanitizerValue(SanitizerName, /*AllowGroups=*/true) == 0)
+    if (parseSanitizerValue(SanitizerName, /*AllowGroups=*/true) ==
+        SanitizerMask())
       S.Diag(LiteralLoc, diag::warn_unknown_sanitizer_ignored) << SanitizerName;
     else if (isGlobalVar(D) && SanitizerName != "address")
       S.Diag(D->getLocation(), diag::err_attribute_wrong_decl_type)