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Export of internal Abseil changes

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--
d35c72d705155dcd89a92835103540f14c643d10 by Gennadiy Rozental <rogeeff@google.com>:

helpxml changed to report types of flags with built-in value type.

PiperOrigin-RevId: 275131440

--
f3478792943d7dd40a6ef6083a8e5d374f43a65e by Abseil Team <absl-team@google.com>:

Add space padding tests for hex conversions.

PiperOrigin-RevId: 275120155

--
7c2e4725403e173660f33f94af686a75d3722936 by Andy Soffer <asoffer@google.com>:

Fix https://github.com/abseil/abseil-cpp/issues/379
by renaming `roundup` to `round_up`

PiperOrigin-RevId: 275106110

--
84cb30d6ee509961ac4359cfdda1360973b9527d by Laramie Leavitt <lar@google.com>:

Move random_internal::wide_multiply into a file by the same name.

PiperOrigin-RevId: 275059359

--
06d691a8c187b5d899e7863784b23bdcfd580cb2 by Abseil Team <absl-team@google.com>:

Add missing "return" keyword.

PiperOrigin-RevId: 275036408
GitOrigin-RevId: d35c72d705155dcd89a92835103540f14c643d10
Change-Id: Id837b4de6c9cfe18f0a088363754bfe389df985b
This commit is contained in:
Abseil Team 2019-10-16 15:51:11 -07:00 • committed by Andy Soffer
parent ab3552a189
commit a15364ce4d
12 changed files with 275 additions and 118 deletions
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1
absl/random/BUILD.bazel
View file

@ -76,6 +76,7 @@ cc_library(
"//absl/random/internal:iostream_state_saver",
"//absl/random/internal:traits",
"//absl/random/internal:uniform_helper",
"//absl/random/internal:wide_multiply",
"//absl/strings",
"//absl/types:span",
],

34
absl/random/CMakeLists.txt
View file

@ -65,6 +65,7 @@ absl_cc_library(
absl::random_internal_iostream_state_saver
absl::random_internal_traits
absl::random_internal_uniform_helper
absl::random_internal_wide_multiply
absl::strings
absl::span
absl::type_traits
@ -557,6 +558,22 @@ absl_cc_library(
absl::random_internal_traits
)
# Internal-only target, do not depend on directly.
absl_cc_library(
NAME
random_internal_wide_multiply
HDRS
"internal/wide_multiply.h"
COPTS
${ABSL_DEFAULT_COPTS}
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::bits
absl::config
absl::int128
)
# Internal-only target, do not depend on directly.
absl_cc_library(
NAME
@ -1033,3 +1050,20 @@ absl_cc_test(
absl::random_internal_iostream_state_saver
gtest_main
)
# Internal-only target, do not depend on directly.
absl_cc_test(
NAME
random_internal_wide_multiply_test
SRCS
internal/wide_multiply_test.cc
COPTS
${ABSL_TEST_COPTS}
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::random_internal_wide_multiply
absl::bits
absl::int128
gtest_main
)

27
absl/random/internal/BUILD.bazel
View file

@ -200,6 +200,19 @@ cc_library(
deps = ["//absl/base:bits"],
)
cc_library(
name = "wide_multiply",
hdrs = ["wide_multiply.h"],
copts = ABSL_DEFAULT_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
":traits",
"//absl/base:bits",
"//absl/base:config",
"//absl/numeric:int128",
],
)
cc_library(
name = "nonsecure_base",
hdrs = ["nonsecure_base.h"],
@ -598,6 +611,20 @@ cc_test(
],
)
cc_test(
name = "wide_multiply_test",
size = "small",
srcs = ["wide_multiply_test.cc"],
copts = ABSL_TEST_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
":wide_multiply",
"//absl/base:bits",
"//absl/numeric:int128",
"@com_google_googletest//:gtest_main",
],
)
cc_library(
name = "nanobenchmark",
srcs = ["nanobenchmark.cc"],

66
absl/random/internal/distribution_impl.h
View file

@ -188,72 +188,6 @@ struct RandU64ToReal<float> {
}
};
inline uint128 MultiplyU64ToU128(uint64_t a, uint64_t b) {
#if defined(ABSL_HAVE_INTRINSIC_INT128)
return uint128(static_cast<__uint128_t>(a) * b);
#elif defined(ABSL_INTERNAL_USE_UMUL128)
// uint64_t * uint64_t => uint128 multiply using imul intrinsic on MSVC.
uint64_t high = 0;
const uint64_t low = _umul128(a, b, &high);
return absl::MakeUint128(high, low);
#else
// uint128(a) * uint128(b) in emulated mode computes a full 128-bit x 128-bit
// multiply. However there are many cases where that is not necessary, and it
// is only necessary to support a 64-bit x 64-bit = 128-bit multiply. This is
// for those cases.
const uint64_t a00 = static_cast<uint32_t>(a);
const uint64_t a32 = a >> 32;
const uint64_t b00 = static_cast<uint32_t>(b);
const uint64_t b32 = b >> 32;
const uint64_t c00 = a00 * b00;
const uint64_t c32a = a00 * b32;
const uint64_t c32b = a32 * b00;
const uint64_t c64 = a32 * b32;
const uint32_t carry =
static_cast<uint32_t>(((c00 >> 32) + static_cast<uint32_t>(c32a) +
static_cast<uint32_t>(c32b)) >>
32);
return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry,
c00 + (c32a << 32) + (c32b << 32));
#endif
}
// wide_multiply<T> multiplies two N-bit values to a 2N-bit result.
template <typename UIntType>
struct wide_multiply {
static constexpr size_t kN = std::numeric_limits<UIntType>::digits;
using input_type = UIntType;
using result_type = typename random_internal::unsigned_bits<kN * 2>::type;
static result_type multiply(input_type a, input_type b) {
return static_cast<result_type>(a) * b;
}
static input_type hi(result_type r) { return r >> kN; }
static input_type lo(result_type r) { return r; }
static_assert(std::is_unsigned<UIntType>::value,
"Class-template wide_multiply<> argument must be unsigned.");
};
#ifndef ABSL_HAVE_INTRINSIC_INT128
template <>
struct wide_multiply<uint64_t> {
using input_type = uint64_t;
using result_type = uint128;
static result_type multiply(uint64_t a, uint64_t b) {
return MultiplyU64ToU128(a, b);
}
static uint64_t hi(result_type r) { return Uint128High64(r); }
static uint64_t lo(result_type r) { return Uint128Low64(r); }
};
#endif
} // namespace random_internal
} // namespace absl

42
absl/random/internal/distribution_impl_test.cc
View file

@ -461,46 +461,4 @@ TEST(DistributionImplTest, ExhaustiveFloat) {
}
}
TEST(DistributionImplTest, MultiplyU64ToU128Test) {
using absl::random_internal::MultiplyU64ToU128;
constexpr uint64_t k1 = 1;
constexpr uint64_t kMax = ~static_cast<uint64_t>(0);
EXPECT_EQ(absl::uint128(0), MultiplyU64ToU128(0, 0));
// Max uint64
EXPECT_EQ(MultiplyU64ToU128(kMax, kMax),
absl::MakeUint128(0xfffffffffffffffe, 0x0000000000000001));
EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(kMax, 1));
EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(1, kMax));
for (int i = 0; i < 64; ++i) {
EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
MultiplyU64ToU128(kMax, k1 << i));
EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
MultiplyU64ToU128(k1 << i, kMax));
}
// 1-bit x 1-bit.
for (int i = 0; i < 64; ++i) {
for (int j = 0; j < 64; ++j) {
EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
MultiplyU64ToU128(k1 << i, k1 << j));
EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
MultiplyU64ToU128(k1 << i, k1 << j));
}
}
// Verified multiplies
EXPECT_EQ(MultiplyU64ToU128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888),
absl::MakeUint128(0xbbbb9e2692c5dddc, 0xc28f7531048d2c60));
EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfedcba9876543210),
absl::MakeUint128(0x0121fa00ad77d742, 0x2236d88fe5618cf0));
EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfdb97531eca86420),
absl::MakeUint128(0x0120ae99d26725fc, 0xce197f0ecac319e0));
EXPECT_EQ(MultiplyU64ToU128(0x97a87f4f261ba3f2, 0xfedcba9876543210),
absl::MakeUint128(0x96fbf1a8ae78d0ba, 0x5a6dd4b71f278320));
EXPECT_EQ(MultiplyU64ToU128(0xfedcba9876543210, 0xfdb97531eca86420),
absl::MakeUint128(0xfc98c6981a413e22, 0x342d0bbf48948200));
}
} // namespace

109
absl/random/internal/wide_multiply.h Normal file
View file

@ -0,0 +1,109 @@
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_
#define ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_
#include <cstdint>
#include <limits>
#include <type_traits>
#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_IA64)
#include <intrin.h> // NOLINT(build/include_order)
#pragma intrinsic(_umul128)
#define ABSL_INTERNAL_USE_UMUL128 1
#endif
#include "absl/base/config.h"
#include "absl/base/internal/bits.h"
#include "absl/numeric/int128.h"
#include "absl/random/internal/traits.h"
namespace absl {
namespace random_internal {
// Helper object to multiply two 64-bit values to a 128-bit value.
// MultiplyU64ToU128 multiplies two 64-bit values to a 128-bit value.
// If an intrinsic is available, it is used, otherwise use native 32-bit
// multiplies to construct the result.
inline uint128 MultiplyU64ToU128(uint64_t a, uint64_t b) {
#if defined(ABSL_HAVE_INTRINSIC_INT128)
return uint128(static_cast<__uint128_t>(a) * b);
#elif defined(ABSL_INTERNAL_USE_UMUL128)
// uint64_t * uint64_t => uint128 multiply using imul intrinsic on MSVC.
uint64_t high = 0;
const uint64_t low = _umul128(a, b, &high);
return absl::MakeUint128(high, low);
#else
// uint128(a) * uint128(b) in emulated mode computes a full 128-bit x 128-bit
// multiply. However there are many cases where that is not necessary, and it
// is only necessary to support a 64-bit x 64-bit = 128-bit multiply. This is
// for those cases.
const uint64_t a00 = static_cast<uint32_t>(a);
const uint64_t a32 = a >> 32;
const uint64_t b00 = static_cast<uint32_t>(b);
const uint64_t b32 = b >> 32;
const uint64_t c00 = a00 * b00;
const uint64_t c32a = a00 * b32;
const uint64_t c32b = a32 * b00;
const uint64_t c64 = a32 * b32;
const uint32_t carry =
static_cast<uint32_t>(((c00 >> 32) + static_cast<uint32_t>(c32a) +
static_cast<uint32_t>(c32b)) >>
32);
return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry,
c00 + (c32a << 32) + (c32b << 32));
#endif
}
// wide_multiply<T> multiplies two N-bit values to a 2N-bit result.
template <typename UIntType>
struct wide_multiply {
static constexpr size_t kN = std::numeric_limits<UIntType>::digits;
using input_type = UIntType;
using result_type = typename random_internal::unsigned_bits<kN * 2>::type;
static result_type multiply(input_type a, input_type b) {
return static_cast<result_type>(a) * b;
}
static input_type hi(result_type r) { return r >> kN; }
static input_type lo(result_type r) { return r; }
static_assert(std::is_unsigned<UIntType>::value,
"Class-template wide_multiply<> argument must be unsigned.");
};
#ifndef ABSL_HAVE_INTRINSIC_INT128
template <>
struct wide_multiply<uint64_t> {
using input_type = uint64_t;
using result_type = uint128;
static result_type multiply(uint64_t a, uint64_t b) {
return MultiplyU64ToU128(a, b);
}
static uint64_t hi(result_type r) { return Uint128High64(r); }
static uint64_t lo(result_type r) { return Uint128Low64(r); }
};
#endif
} // namespace random_internal
} // namespace absl
#endif // ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_

66
absl/random/internal/wide_multiply_test.cc Normal file
View file

@ -0,0 +1,66 @@
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/random/internal/wide_multiply.h"
#include "gtest/gtest.h"
#include "absl/base/internal/bits.h"
#include "absl/numeric/int128.h"
using absl::random_internal::MultiplyU64ToU128;
namespace {
TEST(WideMultiplyTest, MultiplyU64ToU128Test) {
constexpr uint64_t k1 = 1;
constexpr uint64_t kMax = ~static_cast<uint64_t>(0);
EXPECT_EQ(absl::uint128(0), MultiplyU64ToU128(0, 0));
// Max uint64
EXPECT_EQ(MultiplyU64ToU128(kMax, kMax),
absl::MakeUint128(0xfffffffffffffffe, 0x0000000000000001));
EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(kMax, 1));
EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(1, kMax));
for (int i = 0; i < 64; ++i) {
EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
MultiplyU64ToU128(kMax, k1 << i));
EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
MultiplyU64ToU128(k1 << i, kMax));
}
// 1-bit x 1-bit.
for (int i = 0; i < 64; ++i) {
for (int j = 0; j < 64; ++j) {
EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
MultiplyU64ToU128(k1 << i, k1 << j));
EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
MultiplyU64ToU128(k1 << i, k1 << j));
}
}
// Verified multiplies
EXPECT_EQ(MultiplyU64ToU128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888),
absl::MakeUint128(0xbbbb9e2692c5dddc, 0xc28f7531048d2c60));
EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfedcba9876543210),
absl::MakeUint128(0x0121fa00ad77d742, 0x2236d88fe5618cf0));
EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfdb97531eca86420),
absl::MakeUint128(0x0120ae99d26725fc, 0xce197f0ecac319e0));
EXPECT_EQ(MultiplyU64ToU128(0x97a87f4f261ba3f2, 0xfedcba9876543210),
absl::MakeUint128(0x96fbf1a8ae78d0ba, 0x5a6dd4b71f278320));
EXPECT_EQ(MultiplyU64ToU128(0xfedcba9876543210, 0xfdb97531eca86420),
absl::MakeUint128(0xfc98c6981a413e22, 0x342d0bbf48948200));
}
} // namespace

1
absl/random/uniform_int_distribution.h
View file

@ -38,6 +38,7 @@
#include "absl/random/internal/fast_uniform_bits.h"
#include "absl/random/internal/iostream_state_saver.h"
#include "absl/random/internal/traits.h"
#include "absl/random/internal/wide_multiply.h"
namespace absl {