Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/ADT/SmallBitVector.h b/linux-x64/clang/include/llvm/ADT/SmallBitVector.h
new file mode 100644
index 0000000..b639174
--- /dev/null
+++ b/linux-x64/clang/include/llvm/ADT/SmallBitVector.h
@@ -0,0 +1,702 @@
+//===- llvm/ADT/SmallBitVector.h - 'Normally small' bit vectors -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the SmallBitVector class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_SMALLBITVECTOR_H
+#define LLVM_ADT_SMALLBITVECTOR_H
+
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Support/MathExtras.h"
+#include <algorithm>
+#include <cassert>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+#include <utility>
+
+namespace llvm {
+
+/// This is a 'bitvector' (really, a variable-sized bit array), optimized for
+/// the case when the array is small. It contains one pointer-sized field, which
+/// is directly used as a plain collection of bits when possible, or as a
+/// pointer to a larger heap-allocated array when necessary. This allows normal
+/// "small" cases to be fast without losing generality for large inputs.
+class SmallBitVector {
+  // TODO: In "large" mode, a pointer to a BitVector is used, leading to an
+  // unnecessary level of indirection. It would be more efficient to use a
+  // pointer to memory containing size, allocation size, and the array of bits.
+  uintptr_t X = 1;
+
+  enum {
+    // The number of bits in this class.
+    NumBaseBits = sizeof(uintptr_t) * CHAR_BIT,
+
+    // One bit is used to discriminate between small and large mode. The
+    // remaining bits are used for the small-mode representation.
+    SmallNumRawBits = NumBaseBits - 1,
+
+    // A few more bits are used to store the size of the bit set in small mode.
+    // Theoretically this is a ceil-log2. These bits are encoded in the most
+    // significant bits of the raw bits.
+    SmallNumSizeBits = (NumBaseBits == 32 ? 5 :
+                        NumBaseBits == 64 ? 6 :
+                        SmallNumRawBits),
+
+    // The remaining bits are used to store the actual set in small mode.
+    SmallNumDataBits = SmallNumRawBits - SmallNumSizeBits
+  };
+
+  static_assert(NumBaseBits == 64 || NumBaseBits == 32,
+                "Unsupported word size");
+
+public:
+  using size_type = unsigned;
+
+  // Encapsulation of a single bit.
+  class reference {
+    SmallBitVector &TheVector;
+    unsigned BitPos;
+
+  public:
+    reference(SmallBitVector &b, unsigned Idx) : TheVector(b), BitPos(Idx) {}
+
+    reference(const reference&) = default;
+
+    reference& operator=(reference t) {
+      *this = bool(t);
+      return *this;
+    }
+
+    reference& operator=(bool t) {
+      if (t)
+        TheVector.set(BitPos);
+      else
+        TheVector.reset(BitPos);
+      return *this;
+    }
+
+    operator bool() const {
+      return const_cast<const SmallBitVector &>(TheVector).operator[](BitPos);
+    }
+  };
+
+private:
+  bool isSmall() const {
+    return X & uintptr_t(1);
+  }
+
+  BitVector *getPointer() const {
+    assert(!isSmall());
+    return reinterpret_cast<BitVector *>(X);
+  }
+
+  void switchToSmall(uintptr_t NewSmallBits, size_t NewSize) {
+    X = 1;
+    setSmallSize(NewSize);
+    setSmallBits(NewSmallBits);
+  }
+
+  void switchToLarge(BitVector *BV) {
+    X = reinterpret_cast<uintptr_t>(BV);
+    assert(!isSmall() && "Tried to use an unaligned pointer");
+  }
+
+  // Return all the bits used for the "small" representation; this includes
+  // bits for the size as well as the element bits.
+  uintptr_t getSmallRawBits() const {
+    assert(isSmall());
+    return X >> 1;
+  }
+
+  void setSmallRawBits(uintptr_t NewRawBits) {
+    assert(isSmall());
+    X = (NewRawBits << 1) | uintptr_t(1);
+  }
+
+  // Return the size.
+  size_t getSmallSize() const { return getSmallRawBits() >> SmallNumDataBits; }
+
+  void setSmallSize(size_t Size) {
+    setSmallRawBits(getSmallBits() | (Size << SmallNumDataBits));
+  }
+
+  // Return the element bits.
+  uintptr_t getSmallBits() const {
+    return getSmallRawBits() & ~(~uintptr_t(0) << getSmallSize());
+  }
+
+  void setSmallBits(uintptr_t NewBits) {
+    setSmallRawBits((NewBits & ~(~uintptr_t(0) << getSmallSize())) |
+                    (getSmallSize() << SmallNumDataBits));
+  }
+
+public:
+  /// Creates an empty bitvector.
+  SmallBitVector() = default;
+
+  /// Creates a bitvector of specified number of bits. All bits are initialized
+  /// to the specified value.
+  explicit SmallBitVector(unsigned s, bool t = false) {
+    if (s <= SmallNumDataBits)
+      switchToSmall(t ? ~uintptr_t(0) : 0, s);
+    else
+      switchToLarge(new BitVector(s, t));
+  }
+
+  /// SmallBitVector copy ctor.
+  SmallBitVector(const SmallBitVector &RHS) {
+    if (RHS.isSmall())
+      X = RHS.X;
+    else
+      switchToLarge(new BitVector(*RHS.getPointer()));
+  }
+
+  SmallBitVector(SmallBitVector &&RHS) : X(RHS.X) {
+    RHS.X = 1;
+  }
+
+  ~SmallBitVector() {
+    if (!isSmall())
+      delete getPointer();
+  }
+
+  using const_set_bits_iterator = const_set_bits_iterator_impl<SmallBitVector>;
+  using set_iterator = const_set_bits_iterator;
+
+  const_set_bits_iterator set_bits_begin() const {
+    return const_set_bits_iterator(*this);
+  }
+
+  const_set_bits_iterator set_bits_end() const {
+    return const_set_bits_iterator(*this, -1);
+  }
+
+  iterator_range<const_set_bits_iterator> set_bits() const {
+    return make_range(set_bits_begin(), set_bits_end());
+  }
+
+  /// Tests whether there are no bits in this bitvector.
+  bool empty() const {
+    return isSmall() ? getSmallSize() == 0 : getPointer()->empty();
+  }
+
+  /// Returns the number of bits in this bitvector.
+  size_t size() const {
+    return isSmall() ? getSmallSize() : getPointer()->size();
+  }
+
+  /// Returns the number of bits which are set.
+  size_type count() const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      return countPopulation(Bits);
+    }
+    return getPointer()->count();
+  }
+
+  /// Returns true if any bit is set.
+  bool any() const {
+    if (isSmall())
+      return getSmallBits() != 0;
+    return getPointer()->any();
+  }
+
+  /// Returns true if all bits are set.
+  bool all() const {
+    if (isSmall())
+      return getSmallBits() == (uintptr_t(1) << getSmallSize()) - 1;
+    return getPointer()->all();
+  }
+
+  /// Returns true if none of the bits are set.
+  bool none() const {
+    if (isSmall())
+      return getSmallBits() == 0;
+    return getPointer()->none();
+  }
+
+  /// Returns the index of the first set bit, -1 if none of the bits are set.
+  int find_first() const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      if (Bits == 0)
+        return -1;
+      return countTrailingZeros(Bits);
+    }
+    return getPointer()->find_first();
+  }
+
+  int find_last() const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      if (Bits == 0)
+        return -1;
+      return NumBaseBits - countLeadingZeros(Bits);
+    }
+    return getPointer()->find_last();
+  }
+
+  /// Returns the index of the first unset bit, -1 if all of the bits are set.
+  int find_first_unset() const {
+    if (isSmall()) {
+      if (count() == getSmallSize())
+        return -1;
+
+      uintptr_t Bits = getSmallBits();
+      return countTrailingOnes(Bits);
+    }
+    return getPointer()->find_first_unset();
+  }
+
+  int find_last_unset() const {
+    if (isSmall()) {
+      if (count() == getSmallSize())
+        return -1;
+
+      uintptr_t Bits = getSmallBits();
+      return NumBaseBits - countLeadingOnes(Bits);
+    }
+    return getPointer()->find_last_unset();
+  }
+
+  /// Returns the index of the next set bit following the "Prev" bit.
+  /// Returns -1 if the next set bit is not found.
+  int find_next(unsigned Prev) const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      // Mask off previous bits.
+      Bits &= ~uintptr_t(0) << (Prev + 1);
+      if (Bits == 0 || Prev + 1 >= getSmallSize())
+        return -1;
+      return countTrailingZeros(Bits);
+    }
+    return getPointer()->find_next(Prev);
+  }
+
+  /// Returns the index of the next unset bit following the "Prev" bit.
+  /// Returns -1 if the next unset bit is not found.
+  int find_next_unset(unsigned Prev) const {
+    if (isSmall()) {
+      ++Prev;
+      uintptr_t Bits = getSmallBits();
+      // Mask in previous bits.
+      uintptr_t Mask = (1 << Prev) - 1;
+      Bits |= Mask;
+
+      if (Bits == ~uintptr_t(0) || Prev + 1 >= getSmallSize())
+        return -1;
+      return countTrailingOnes(Bits);
+    }
+    return getPointer()->find_next_unset(Prev);
+  }
+
+  /// find_prev - Returns the index of the first set bit that precedes the
+  /// the bit at \p PriorTo.  Returns -1 if all previous bits are unset.
+  int find_prev(unsigned PriorTo) const {
+    if (isSmall()) {
+      if (PriorTo == 0)
+        return -1;
+
+      --PriorTo;
+      uintptr_t Bits = getSmallBits();
+      Bits &= maskTrailingOnes<uintptr_t>(PriorTo + 1);
+      if (Bits == 0)
+        return -1;
+
+      return NumBaseBits - countLeadingZeros(Bits) - 1;
+    }
+    return getPointer()->find_prev(PriorTo);
+  }
+
+  /// Clear all bits.
+  void clear() {
+    if (!isSmall())
+      delete getPointer();
+    switchToSmall(0, 0);
+  }
+
+  /// Grow or shrink the bitvector.
+  void resize(unsigned N, bool t = false) {
+    if (!isSmall()) {
+      getPointer()->resize(N, t);
+    } else if (SmallNumDataBits >= N) {
+      uintptr_t NewBits = t ? ~uintptr_t(0) << getSmallSize() : 0;
+      setSmallSize(N);
+      setSmallBits(NewBits | getSmallBits());
+    } else {
+      BitVector *BV = new BitVector(N, t);
+      uintptr_t OldBits = getSmallBits();
+      for (size_t i = 0, e = getSmallSize(); i != e; ++i)
+        (*BV)[i] = (OldBits >> i) & 1;
+      switchToLarge(BV);
+    }
+  }
+
+  void reserve(unsigned N) {
+    if (isSmall()) {
+      if (N > SmallNumDataBits) {
+        uintptr_t OldBits = getSmallRawBits();
+        size_t SmallSize = getSmallSize();
+        BitVector *BV = new BitVector(SmallSize);
+        for (size_t i = 0; i < SmallSize; ++i)
+          if ((OldBits >> i) & 1)
+            BV->set(i);
+        BV->reserve(N);
+        switchToLarge(BV);
+      }
+    } else {
+      getPointer()->reserve(N);
+    }
+  }
+
+  // Set, reset, flip
+  SmallBitVector &set() {
+    if (isSmall())
+      setSmallBits(~uintptr_t(0));
+    else
+      getPointer()->set();
+    return *this;
+  }
+
+  SmallBitVector &set(unsigned Idx) {
+    if (isSmall()) {
+      assert(Idx <= static_cast<unsigned>(
+                        std::numeric_limits<uintptr_t>::digits) &&
+             "undefined behavior");
+      setSmallBits(getSmallBits() | (uintptr_t(1) << Idx));
+    }
+    else
+      getPointer()->set(Idx);
+    return *this;
+  }
+
+  /// Efficiently set a range of bits in [I, E)
+  SmallBitVector &set(unsigned I, unsigned E) {
+    assert(I <= E && "Attempted to set backwards range!");
+    assert(E <= size() && "Attempted to set out-of-bounds range!");
+    if (I == E) return *this;
+    if (isSmall()) {
+      uintptr_t EMask = ((uintptr_t)1) << E;
+      uintptr_t IMask = ((uintptr_t)1) << I;
+      uintptr_t Mask = EMask - IMask;
+      setSmallBits(getSmallBits() | Mask);
+    } else
+      getPointer()->set(I, E);
+    return *this;
+  }
+
+  SmallBitVector &reset() {
+    if (isSmall())
+      setSmallBits(0);
+    else
+      getPointer()->reset();
+    return *this;
+  }
+
+  SmallBitVector &reset(unsigned Idx) {
+    if (isSmall())
+      setSmallBits(getSmallBits() & ~(uintptr_t(1) << Idx));
+    else
+      getPointer()->reset(Idx);
+    return *this;
+  }
+
+  /// Efficiently reset a range of bits in [I, E)
+  SmallBitVector &reset(unsigned I, unsigned E) {
+    assert(I <= E && "Attempted to reset backwards range!");
+    assert(E <= size() && "Attempted to reset out-of-bounds range!");
+    if (I == E) return *this;
+    if (isSmall()) {
+      uintptr_t EMask = ((uintptr_t)1) << E;
+      uintptr_t IMask = ((uintptr_t)1) << I;
+      uintptr_t Mask = EMask - IMask;
+      setSmallBits(getSmallBits() & ~Mask);
+    } else
+      getPointer()->reset(I, E);
+    return *this;
+  }
+
+  SmallBitVector &flip() {
+    if (isSmall())
+      setSmallBits(~getSmallBits());
+    else
+      getPointer()->flip();
+    return *this;
+  }
+
+  SmallBitVector &flip(unsigned Idx) {
+    if (isSmall())
+      setSmallBits(getSmallBits() ^ (uintptr_t(1) << Idx));
+    else
+      getPointer()->flip(Idx);
+    return *this;
+  }
+
+  // No argument flip.
+  SmallBitVector operator~() const {
+    return SmallBitVector(*this).flip();
+  }
+
+  // Indexing.
+  reference operator[](unsigned Idx) {
+    assert(Idx < size() && "Out-of-bounds Bit access.");
+    return reference(*this, Idx);
+  }
+
+  bool operator[](unsigned Idx) const {
+    assert(Idx < size() && "Out-of-bounds Bit access.");
+    if (isSmall())
+      return ((getSmallBits() >> Idx) & 1) != 0;
+    return getPointer()->operator[](Idx);
+  }
+
+  bool test(unsigned Idx) const {
+    return (*this)[Idx];
+  }
+
+  /// Test if any common bits are set.
+  bool anyCommon(const SmallBitVector &RHS) const {
+    if (isSmall() && RHS.isSmall())
+      return (getSmallBits() & RHS.getSmallBits()) != 0;
+    if (!isSmall() && !RHS.isSmall())
+      return getPointer()->anyCommon(*RHS.getPointer());
+
+    for (unsigned i = 0, e = std::min(size(), RHS.size()); i != e; ++i)
+      if (test(i) && RHS.test(i))
+        return true;
+    return false;
+  }
+
+  // Comparison operators.
+  bool operator==(const SmallBitVector &RHS) const {
+    if (size() != RHS.size())
+      return false;
+    if (isSmall())
+      return getSmallBits() == RHS.getSmallBits();
+    else
+      return *getPointer() == *RHS.getPointer();
+  }
+
+  bool operator!=(const SmallBitVector &RHS) const {
+    return !(*this == RHS);
+  }
+
+  // Intersection, union, disjoint union.
+  SmallBitVector &operator&=(const SmallBitVector &RHS) {
+    resize(std::max(size(), RHS.size()));
+    if (isSmall())
+      setSmallBits(getSmallBits() & RHS.getSmallBits());
+    else if (!RHS.isSmall())
+      getPointer()->operator&=(*RHS.getPointer());
+    else {
+      SmallBitVector Copy = RHS;
+      Copy.resize(size());
+      getPointer()->operator&=(*Copy.getPointer());
+    }
+    return *this;
+  }
+
+  /// Reset bits that are set in RHS. Same as *this &= ~RHS.
+  SmallBitVector &reset(const SmallBitVector &RHS) {
+    if (isSmall() && RHS.isSmall())
+      setSmallBits(getSmallBits() & ~RHS.getSmallBits());
+    else if (!isSmall() && !RHS.isSmall())
+      getPointer()->reset(*RHS.getPointer());
+    else
+      for (unsigned i = 0, e = std::min(size(), RHS.size()); i != e; ++i)
+        if (RHS.test(i))
+          reset(i);
+
+    return *this;
+  }
+
+  /// Check if (This - RHS) is zero. This is the same as reset(RHS) and any().
+  bool test(const SmallBitVector &RHS) const {
+    if (isSmall() && RHS.isSmall())
+      return (getSmallBits() & ~RHS.getSmallBits()) != 0;
+    if (!isSmall() && !RHS.isSmall())
+      return getPointer()->test(*RHS.getPointer());
+
+    unsigned i, e;
+    for (i = 0, e = std::min(size(), RHS.size()); i != e; ++i)
+      if (test(i) && !RHS.test(i))
+        return true;
+
+    for (e = size(); i != e; ++i)
+      if (test(i))
+        return true;
+
+    return false;
+  }
+
+  SmallBitVector &operator|=(const SmallBitVector &RHS) {
+    resize(std::max(size(), RHS.size()));
+    if (isSmall())
+      setSmallBits(getSmallBits() | RHS.getSmallBits());
+    else if (!RHS.isSmall())
+      getPointer()->operator|=(*RHS.getPointer());
+    else {
+      SmallBitVector Copy = RHS;
+      Copy.resize(size());
+      getPointer()->operator|=(*Copy.getPointer());
+    }
+    return *this;
+  }
+
+  SmallBitVector &operator^=(const SmallBitVector &RHS) {
+    resize(std::max(size(), RHS.size()));
+    if (isSmall())
+      setSmallBits(getSmallBits() ^ RHS.getSmallBits());
+    else if (!RHS.isSmall())
+      getPointer()->operator^=(*RHS.getPointer());
+    else {
+      SmallBitVector Copy = RHS;
+      Copy.resize(size());
+      getPointer()->operator^=(*Copy.getPointer());
+    }
+    return *this;
+  }
+
+  SmallBitVector &operator<<=(unsigned N) {
+    if (isSmall())
+      setSmallBits(getSmallBits() << N);
+    else
+      getPointer()->operator<<=(N);
+    return *this;
+  }
+
+  SmallBitVector &operator>>=(unsigned N) {
+    if (isSmall())
+      setSmallBits(getSmallBits() >> N);
+    else
+      getPointer()->operator>>=(N);
+    return *this;
+  }
+
+  // Assignment operator.
+  const SmallBitVector &operator=(const SmallBitVector &RHS) {
+    if (isSmall()) {
+      if (RHS.isSmall())
+        X = RHS.X;
+      else
+        switchToLarge(new BitVector(*RHS.getPointer()));
+    } else {
+      if (!RHS.isSmall())
+        *getPointer() = *RHS.getPointer();
+      else {
+        delete getPointer();
+        X = RHS.X;
+      }
+    }
+    return *this;
+  }
+
+  const SmallBitVector &operator=(SmallBitVector &&RHS) {
+    if (this != &RHS) {
+      clear();
+      swap(RHS);
+    }
+    return *this;
+  }
+
+  void swap(SmallBitVector &RHS) {
+    std::swap(X, RHS.X);
+  }
+
+  /// Add '1' bits from Mask to this vector. Don't resize.
+  /// This computes "*this |= Mask".
+  void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+    if (isSmall())
+      applyMask<true, false>(Mask, MaskWords);
+    else
+      getPointer()->setBitsInMask(Mask, MaskWords);
+  }
+
+  /// Clear any bits in this vector that are set in Mask. Don't resize.
+  /// This computes "*this &= ~Mask".
+  void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+    if (isSmall())
+      applyMask<false, false>(Mask, MaskWords);
+    else
+      getPointer()->clearBitsInMask(Mask, MaskWords);
+  }
+
+  /// Add a bit to this vector for every '0' bit in Mask. Don't resize.
+  /// This computes "*this |= ~Mask".
+  void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+    if (isSmall())
+      applyMask<true, true>(Mask, MaskWords);
+    else
+      getPointer()->setBitsNotInMask(Mask, MaskWords);
+  }
+
+  /// Clear a bit in this vector for every '0' bit in Mask. Don't resize.
+  /// This computes "*this &= Mask".
+  void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+    if (isSmall())
+      applyMask<false, true>(Mask, MaskWords);
+    else
+      getPointer()->clearBitsNotInMask(Mask, MaskWords);
+  }
+
+private:
+  template <bool AddBits, bool InvertMask>
+  void applyMask(const uint32_t *Mask, unsigned MaskWords) {
+    assert(MaskWords <= sizeof(uintptr_t) && "Mask is larger than base!");
+    uintptr_t M = Mask[0];
+    if (NumBaseBits == 64)
+      M |= uint64_t(Mask[1]) << 32;
+    if (InvertMask)
+      M = ~M;
+    if (AddBits)
+      setSmallBits(getSmallBits() | M);
+    else
+      setSmallBits(getSmallBits() & ~M);
+  }
+};
+
+inline SmallBitVector
+operator&(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result &= RHS;
+  return Result;
+}
+
+inline SmallBitVector
+operator|(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result |= RHS;
+  return Result;
+}
+
+inline SmallBitVector
+operator^(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result ^= RHS;
+  return Result;
+}
+
+} // end namespace llvm
+
+namespace std {
+
+/// Implement std::swap in terms of BitVector swap.
+inline void
+swap(llvm::SmallBitVector &LHS, llvm::SmallBitVector &RHS) {
+  LHS.swap(RHS);
+}
+
+} // end namespace std
+
+#endif // LLVM_ADT_SMALLBITVECTOR_H