src/v8/test/unittests/base/bits-unittest.cc

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <limits>

#include "src/base/bits.h"
#include "src/base/macros.h"
#include "testing/gtest-support.h"

#ifdef DEBUG
#define DISABLE_IN_RELEASE(Name) Name
#else
#define DISABLE_IN_RELEASE(Name) DISABLED_##Name
#endif

namespace v8 {
namespace base {
namespace bits {

TEST(Bits, CountPopulation16) {
  EXPECT_EQ(0u, CountPopulation(uint16_t{0}));
  EXPECT_EQ(1u, CountPopulation(uint16_t{1}));
  EXPECT_EQ(4u, CountPopulation(uint16_t{0x1111}));
  EXPECT_EQ(8u, CountPopulation(uint16_t{0xF0F0}));
  EXPECT_EQ(12u, CountPopulation(uint16_t{0xF0FF}));
  EXPECT_EQ(16u, CountPopulation(uint16_t{0xFFFF}));
}

TEST(Bits, CountPopulation32) {
  EXPECT_EQ(0u, CountPopulation(uint32_t{0}));
  EXPECT_EQ(1u, CountPopulation(uint32_t{1}));
  EXPECT_EQ(8u, CountPopulation(uint32_t{0x11111111}));
  EXPECT_EQ(16u, CountPopulation(uint32_t{0xF0F0F0F0}));
  EXPECT_EQ(24u, CountPopulation(uint32_t{0xFFF0F0FF}));
  EXPECT_EQ(32u, CountPopulation(uint32_t{0xFFFFFFFF}));
}

TEST(Bits, CountPopulation64) {
  EXPECT_EQ(0u, CountPopulation(uint64_t{0}));
  EXPECT_EQ(1u, CountPopulation(uint64_t{1}));
  EXPECT_EQ(2u, CountPopulation(uint64_t{0x8000000000000001}));
  EXPECT_EQ(8u, CountPopulation(uint64_t{0x11111111}));
  EXPECT_EQ(16u, CountPopulation(uint64_t{0xF0F0F0F0}));
  EXPECT_EQ(24u, CountPopulation(uint64_t{0xFFF0F0FF}));
  EXPECT_EQ(32u, CountPopulation(uint64_t{0xFFFFFFFF}));
  EXPECT_EQ(16u, CountPopulation(uint64_t{0x1111111111111111}));
  EXPECT_EQ(32u, CountPopulation(uint64_t{0xF0F0F0F0F0F0F0F0}));
  EXPECT_EQ(48u, CountPopulation(uint64_t{0xFFF0F0FFFFF0F0FF}));
  EXPECT_EQ(64u, CountPopulation(uint64_t{0xFFFFFFFFFFFFFFFF}));
}

TEST(Bits, CountLeadingZeros16) {
  EXPECT_EQ(16u, CountLeadingZeros(uint16_t{0}));
  EXPECT_EQ(15u, CountLeadingZeros(uint16_t{1}));
  TRACED_FORRANGE(uint16_t, shift, 0, 15) {
    EXPECT_EQ(15u - shift,
              CountLeadingZeros(static_cast<uint16_t>(1 << shift)));
  }
  EXPECT_EQ(4u, CountLeadingZeros(uint16_t{0x0F0F}));
}

TEST(Bits, CountLeadingZeros32) {
  EXPECT_EQ(32u, CountLeadingZeros(uint32_t{0}));
  EXPECT_EQ(31u, CountLeadingZeros(uint32_t{1}));
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(31u - shift, CountLeadingZeros(uint32_t{1} << shift));
  }
  EXPECT_EQ(4u, CountLeadingZeros(uint32_t{0x0F0F0F0F}));
}

TEST(Bits, CountLeadingZeros64) {
  EXPECT_EQ(64u, CountLeadingZeros(uint64_t{0}));
  EXPECT_EQ(63u, CountLeadingZeros(uint64_t{1}));
  TRACED_FORRANGE(uint32_t, shift, 0, 63) {
    EXPECT_EQ(63u - shift, CountLeadingZeros(uint64_t{1} << shift));
  }
  EXPECT_EQ(36u, CountLeadingZeros(uint64_t{0x0F0F0F0F}));
  EXPECT_EQ(4u, CountLeadingZeros(uint64_t{0x0F0F0F0F00000000}));
}

TEST(Bits, CountTrailingZeros16) {
  EXPECT_EQ(16u, CountTrailingZeros(uint16_t{0}));
  EXPECT_EQ(15u, CountTrailingZeros(uint16_t{0x8000}));
  TRACED_FORRANGE(uint16_t, shift, 0, 15) {
    EXPECT_EQ(shift, CountTrailingZeros(static_cast<uint16_t>(1 << shift)));
  }
  EXPECT_EQ(4u, CountTrailingZeros(uint16_t{0xF0F0u}));
}

TEST(Bits, CountTrailingZerosu32) {
  EXPECT_EQ(32u, CountTrailingZeros(uint32_t{0}));
  EXPECT_EQ(31u, CountTrailingZeros(uint32_t{0x80000000}));
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(shift, CountTrailingZeros(uint32_t{1} << shift));
  }
  EXPECT_EQ(4u, CountTrailingZeros(uint32_t{0xF0F0F0F0u}));
}

TEST(Bits, CountTrailingZerosi32) {
  EXPECT_EQ(32u, CountTrailingZeros(int32_t{0}));
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(shift, CountTrailingZeros(int32_t{1} << shift));
  }
  EXPECT_EQ(4u, CountTrailingZeros(int32_t{0x70F0F0F0u}));
  EXPECT_EQ(2u, CountTrailingZeros(int32_t{-4}));
  EXPECT_EQ(0u, CountTrailingZeros(int32_t{-1}));
}

TEST(Bits, CountTrailingZeros64) {
  EXPECT_EQ(64u, CountTrailingZeros(uint64_t{0}));
  EXPECT_EQ(63u, CountTrailingZeros(uint64_t{0x8000000000000000}));
  TRACED_FORRANGE(uint32_t, shift, 0, 63) {
    EXPECT_EQ(shift, CountTrailingZeros(uint64_t{1} << shift));
  }
  EXPECT_EQ(4u, CountTrailingZeros(uint64_t{0xF0F0F0F0}));
  EXPECT_EQ(36u, CountTrailingZeros(uint64_t{0xF0F0F0F000000000}));
}


TEST(Bits, IsPowerOfTwo32) {
  EXPECT_FALSE(IsPowerOfTwo(0U));
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_TRUE(IsPowerOfTwo(1U << shift));
    EXPECT_FALSE(IsPowerOfTwo((1U << shift) + 5U));
    EXPECT_FALSE(IsPowerOfTwo(~(1U << shift)));
  }
  TRACED_FORRANGE(uint32_t, shift, 2, 31) {
    EXPECT_FALSE(IsPowerOfTwo((1U << shift) - 1U));
  }
  EXPECT_FALSE(IsPowerOfTwo(0xFFFFFFFF));
}


TEST(Bits, IsPowerOfTwo64) {
  EXPECT_FALSE(IsPowerOfTwo(uint64_t{0}));
  TRACED_FORRANGE(uint32_t, shift, 0, 63) {
    EXPECT_TRUE(IsPowerOfTwo(uint64_t{1} << shift));
    EXPECT_FALSE(IsPowerOfTwo((uint64_t{1} << shift) + 5U));
    EXPECT_FALSE(IsPowerOfTwo(~(uint64_t{1} << shift)));
  }
  TRACED_FORRANGE(uint32_t, shift, 2, 63) {
    EXPECT_FALSE(IsPowerOfTwo((uint64_t{1} << shift) - 1U));
  }
  EXPECT_FALSE(IsPowerOfTwo(uint64_t{0xFFFFFFFFFFFFFFFF}));
}


TEST(Bits, RoundUpToPowerOfTwo32) {
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(1u << shift, RoundUpToPowerOfTwo32(1u << shift));
  }
  EXPECT_EQ(1u, RoundUpToPowerOfTwo32(0));
  EXPECT_EQ(1u, RoundUpToPowerOfTwo32(1));
  EXPECT_EQ(4u, RoundUpToPowerOfTwo32(3));
  EXPECT_EQ(0x80000000u, RoundUpToPowerOfTwo32(0x7FFFFFFFu));
}


TEST(BitsDeathTest, DISABLE_IN_RELEASE(RoundUpToPowerOfTwo32)) {
  ASSERT_DEATH_IF_SUPPORTED({ RoundUpToPowerOfTwo32(0x80000001u); },
                            ".*heck failed:.* << 31");
}

TEST(Bits, RoundUpToPowerOfTwo64) {
  TRACED_FORRANGE(uint64_t, shift, 0, 63) {
    uint64_t value = uint64_t{1} << shift;
    EXPECT_EQ(value, RoundUpToPowerOfTwo64(value));
  }
  EXPECT_EQ(uint64_t{1}, RoundUpToPowerOfTwo64(0));
  EXPECT_EQ(uint64_t{1}, RoundUpToPowerOfTwo64(1));
  EXPECT_EQ(uint64_t{4}, RoundUpToPowerOfTwo64(3));
  EXPECT_EQ(uint64_t{1} << 63, RoundUpToPowerOfTwo64((uint64_t{1} << 63) - 1));
  EXPECT_EQ(uint64_t{1} << 63, RoundUpToPowerOfTwo64(uint64_t{1} << 63));
}

TEST(BitsDeathTest, DISABLE_IN_RELEASE(RoundUpToPowerOfTwo64)) {
  ASSERT_DEATH_IF_SUPPORTED({ RoundUpToPowerOfTwo64((uint64_t{1} << 63) + 1); },
                            ".*heck failed:.* << 63");
}


TEST(Bits, RoundDownToPowerOfTwo32) {
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(1u << shift, RoundDownToPowerOfTwo32(1u << shift));
  }
  EXPECT_EQ(0u, RoundDownToPowerOfTwo32(0));
  EXPECT_EQ(4u, RoundDownToPowerOfTwo32(5));
  EXPECT_EQ(0x80000000u, RoundDownToPowerOfTwo32(0x80000001u));
}


TEST(Bits, RotateRight32) {
  TRACED_FORRANGE(uint32_t, shift, 0, 31) {
    EXPECT_EQ(0u, RotateRight32(0u, shift));
  }
  EXPECT_EQ(1u, RotateRight32(1, 0));
  EXPECT_EQ(1u, RotateRight32(2, 1));
  EXPECT_EQ(0x80000000u, RotateRight32(1, 1));
}


TEST(Bits, RotateRight64) {
  TRACED_FORRANGE(uint64_t, shift, 0, 63) {
    EXPECT_EQ(0u, RotateRight64(0u, shift));
  }
  EXPECT_EQ(1u, RotateRight64(1, 0));
  EXPECT_EQ(1u, RotateRight64(2, 1));
  EXPECT_EQ(uint64_t{0x8000000000000000}, RotateRight64(1, 1));
}


TEST(Bits, SignedAddOverflow32) {
  int32_t val = 0;
  EXPECT_FALSE(SignedAddOverflow32(0, 0, &val));
  EXPECT_EQ(0, val);
  EXPECT_TRUE(
      SignedAddOverflow32(std::numeric_limits<int32_t>::max(), 1, &val));
  EXPECT_EQ(std::numeric_limits<int32_t>::min(), val);
  EXPECT_TRUE(
      SignedAddOverflow32(std::numeric_limits<int32_t>::min(), -1, &val));
  EXPECT_EQ(std::numeric_limits<int32_t>::max(), val);
  EXPECT_TRUE(SignedAddOverflow32(std::numeric_limits<int32_t>::max(),
                                  std::numeric_limits<int32_t>::max(), &val));
  EXPECT_EQ(-2, val);
  TRACED_FORRANGE(int32_t, i, 1, 50) {
    TRACED_FORRANGE(int32_t, j, 1, i) {
      EXPECT_FALSE(SignedAddOverflow32(i, j, &val));
      EXPECT_EQ(i + j, val);
    }
  }
}


TEST(Bits, SignedSubOverflow32) {
  int32_t val = 0;
  EXPECT_FALSE(SignedSubOverflow32(0, 0, &val));
  EXPECT_EQ(0, val);
  EXPECT_TRUE(
      SignedSubOverflow32(std::numeric_limits<int32_t>::min(), 1, &val));
  EXPECT_EQ(std::numeric_limits<int32_t>::max(), val);
  EXPECT_TRUE(
      SignedSubOverflow32(std::numeric_limits<int32_t>::max(), -1, &val));
  EXPECT_EQ(std::numeric_limits<int32_t>::min(), val);
  TRACED_FORRANGE(int32_t, i, 1, 50) {
    TRACED_FORRANGE(int32_t, j, 1, i) {
      EXPECT_FALSE(SignedSubOverflow32(i, j, &val));
      EXPECT_EQ(i - j, val);
    }
  }
}


TEST(Bits, SignedMulHigh32) {
  EXPECT_EQ(0, SignedMulHigh32(0, 0));
  TRACED_FORRANGE(int32_t, i, 1, 50) {
    TRACED_FORRANGE(int32_t, j, 1, i) { EXPECT_EQ(0, SignedMulHigh32(i, j)); }
  }
  EXPECT_EQ(-1073741824, SignedMulHigh32(std::numeric_limits<int32_t>::max(),
                                         std::numeric_limits<int32_t>::min()));
  EXPECT_EQ(-1073741824, SignedMulHigh32(std::numeric_limits<int32_t>::min(),
                                         std::numeric_limits<int32_t>::max()));
  EXPECT_EQ(1, SignedMulHigh32(1024 * 1024 * 1024, 4));
  EXPECT_EQ(2, SignedMulHigh32(8 * 1024, 1024 * 1024));
}


TEST(Bits, SignedMulHighAndAdd32) {
  TRACED_FORRANGE(int32_t, i, 1, 50) {
    EXPECT_EQ(i, SignedMulHighAndAdd32(0, 0, i));
    TRACED_FORRANGE(int32_t, j, 1, i) {
      EXPECT_EQ(i, SignedMulHighAndAdd32(j, j, i));
    }
    EXPECT_EQ(i + 1, SignedMulHighAndAdd32(1024 * 1024 * 1024, 4, i));
  }
}


TEST(Bits, SignedDiv32) {
  EXPECT_EQ(std::numeric_limits<int32_t>::min(),
            SignedDiv32(std::numeric_limits<int32_t>::min(), -1));
  EXPECT_EQ(std::numeric_limits<int32_t>::max(),
            SignedDiv32(std::numeric_limits<int32_t>::max(), 1));
  TRACED_FORRANGE(int32_t, i, 0, 50) {
    EXPECT_EQ(0, SignedDiv32(i, 0));
    TRACED_FORRANGE(int32_t, j, 1, i) {
      EXPECT_EQ(1, SignedDiv32(j, j));
      EXPECT_EQ(i / j, SignedDiv32(i, j));
      EXPECT_EQ(-i / j, SignedDiv32(i, -j));
    }
  }
}


TEST(Bits, SignedMod32) {
  EXPECT_EQ(0, SignedMod32(std::numeric_limits<int32_t>::min(), -1));
  EXPECT_EQ(0, SignedMod32(std::numeric_limits<int32_t>::max(), 1));
  TRACED_FORRANGE(int32_t, i, 0, 50) {
    EXPECT_EQ(0, SignedMod32(i, 0));
    TRACED_FORRANGE(int32_t, j, 1, i) {
      EXPECT_EQ(0, SignedMod32(j, j));
      EXPECT_EQ(i % j, SignedMod32(i, j));
      EXPECT_EQ(i % j, SignedMod32(i, -j));
    }
  }
}


TEST(Bits, UnsignedAddOverflow32) {
  uint32_t val = 0;
  EXPECT_FALSE(UnsignedAddOverflow32(0, 0, &val));
  EXPECT_EQ(0u, val);
  EXPECT_TRUE(
      UnsignedAddOverflow32(std::numeric_limits<uint32_t>::max(), 1u, &val));
  EXPECT_EQ(std::numeric_limits<uint32_t>::min(), val);
  EXPECT_TRUE(UnsignedAddOverflow32(std::numeric_limits<uint32_t>::max(),
                                    std::numeric_limits<uint32_t>::max(),
                                    &val));
  TRACED_FORRANGE(uint32_t, i, 1, 50) {
    TRACED_FORRANGE(uint32_t, j, 1, i) {
      EXPECT_FALSE(UnsignedAddOverflow32(i, j, &val));
      EXPECT_EQ(i + j, val);
    }
  }
}


TEST(Bits, UnsignedDiv32) {
  TRACED_FORRANGE(uint32_t, i, 0, 50) {
    EXPECT_EQ(0u, UnsignedDiv32(i, 0));
    TRACED_FORRANGE(uint32_t, j, i + 1, 100) {
      EXPECT_EQ(1u, UnsignedDiv32(j, j));
      EXPECT_EQ(i / j, UnsignedDiv32(i, j));
    }
  }
}


TEST(Bits, UnsignedMod32) {
  TRACED_FORRANGE(uint32_t, i, 0, 50) {
    EXPECT_EQ(0u, UnsignedMod32(i, 0));
    TRACED_FORRANGE(uint32_t, j, i + 1, 100) {
      EXPECT_EQ(0u, UnsignedMod32(j, j));
      EXPECT_EQ(i % j, UnsignedMod32(i, j));
    }
  }
}

}  // namespace bits
}  // namespace base
}  // namespace v8