tvl-depot/absl/random/internal/randen_detect.cc
Abseil Team e9324d926a Export of internal Abseil changes.
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7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 254454546

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ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254451562

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deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson <johnsoncj@google.com>:

Account for subtracting unsigned values from the size of InlinedVector

PiperOrigin-RevId: 254450625

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3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer <asoffer@google.com>:

Add C++17's std::make_from_tuple to absl/utility/utility.h

PiperOrigin-RevId: 254411573

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4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for the rest of the InlinedVector public API

PiperOrigin-RevId: 254408378

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e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson <johnsoncj@google.com>:

Updates the definition of InlinedVector::shrink_to_fit() to be exception safe and adds exception safety tests for it.

PiperOrigin-RevId: 254401387

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2ea82e72b86d82d78b4e4712a63a55981b53c64b by Laramie Leavitt <lar@google.com>:

Use absl::InsecureBitGen in place of std::mt19937
in tests absl/random/...distribution_test.cc

PiperOrigin-RevId: 254289444

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fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254286334

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ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254273059

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6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown <jorg@google.com>:

Change absl::container_internal::CompressedTuple to instantiate its
internal Storage class with the name of the type it's holding, rather
than the name of the Tuple.  This is not an externally-visible change,
other than less compiler memory is used and less debug information is
generated.

PiperOrigin-RevId: 254269285

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8bd3c186bf2fc0c55d8a2dd6f28a5327502c9fba by Andy Soffer <asoffer@google.com>:

Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for
IntervalOpenOpen.

PiperOrigin-RevId: 254252419

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ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team <absl-team@google.com>:

Do not directly use __SIZEOF_INT128__.

In order to avoid linker errors when building with clang-cl (__fixunsdfti, __udivti3 and __fixunssfti are undefined), this CL uses ABSL_HAVE_INTRINSIC_INT128 which is not defined for clang-cl.

PiperOrigin-RevId: 254250739

--
89ab385cd26b34d64130bce856253aaba96d2345 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254242321

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cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for InlinedVector::reserve(size_type)

PiperOrigin-RevId: 254199226

--
c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental <rogeeff@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 254072387

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c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt <lar@google.com>:

Internal cleanup.

PiperOrigin-RevId: 254062381

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d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck <shreck@google.com>:

Update distributions.h to Abseil standards

PiperOrigin-RevId: 254054946

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d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson <johnsoncj@google.com>:

Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions

PiperOrigin-RevId: 254005427

--
2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253999861

--
24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson <johnsoncj@google.com>:

Updates the definition of InlinedVector::assign(...)/InlinedVector::operator=(...) to new, exception-safe implementations with exception safety tests to boot

PiperOrigin-RevId: 253993691

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5613d95f5a7e34a535cfaeadce801441e990843e by CJ Johnson <johnsoncj@google.com>:

Adds benchmarks for InlinedVector::shrink_to_fit()

PiperOrigin-RevId: 253989647

--
2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team <absl-team@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253927497

--
bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253920512

--
bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 253886486

--
05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier <ericwf@google.com>:

Don't include `winsock2.h` because it drags in `windows.h` and friends,
and they define awful macros like OPAQUE, ERROR, and more. This has the
potential to break abseil users.

Instead we only forward declare `timeval` and require Windows users
include `winsock2.h` themselves. This is both inconsistent and poor QoI, but so
including 'windows.h' is bad too.

PiperOrigin-RevId: 253852615
GitOrigin-RevId: 7a6ff16a85beb730c172d5d25cf1b5e1be885c56
Change-Id: Icd6aff87da26f29ec8915da856f051129987cef6
2019-06-21 16:18:10 -04:00

219 lines
7.5 KiB
C++

// 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.
// HERMETIC NOTE: The randen_hwaes target must not introduce duplicate
// symbols from arbitrary system and other headers, since it may be built
// with different flags from other targets, using different levels of
// optimization, potentially introducing ODR violations.
#include "absl/random/internal/randen_detect.h"
#include <cstdint>
#include <cstring>
#include "absl/random/internal/platform.h"
#if defined(ABSL_ARCH_X86_64)
#define ABSL_INTERNAL_USE_X86_CPUID
#elif defined(ABSL_ARCH_PPC) || defined(ABSL_ARCH_ARM) || \
defined(ABSL_ARCH_AARCH64)
#if defined(__ANDROID__)
#define ABSL_INTERNAL_USE_ANDROID_GETAUXVAL
#define ABSL_INTERNAL_USE_GETAUXVAL
#elif defined(__linux__)
#define ABSL_INTERNAL_USE_LINUX_GETAUXVAL
#define ABSL_INTERNAL_USE_GETAUXVAL
#endif
#endif
#if defined(ABSL_INTERNAL_USE_X86_CPUID)
#if defined(_WIN32) || defined(_WIN64)
#include <intrin.h> // NOLINT(build/include_order)
#pragma intrinsic(__cpuid)
#else
// MSVC-equivalent __cpuid intrinsic function.
static void __cpuid(int cpu_info[4], int info_type) {
__asm__ volatile("cpuid \n\t"
: "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
"=d"(cpu_info[3])
: "a"(info_type), "c"(0));
}
#endif
#endif // ABSL_INTERNAL_USE_X86_CPUID
// On linux, just use the c-library getauxval call.
#if defined(ABSL_INTERNAL_USE_LINUX_GETAUXVAL)
extern "C" unsigned long getauxval(unsigned long type); // NOLINT(runtime/int)
static uint32_t GetAuxval(uint32_t hwcap_type) {
return static_cast<uint32_t>(getauxval(hwcap_type));
}
#endif
// On android, probe the system's C library for getauxval().
// This is the same technique used by the android NDK cpu features library
// as well as the google open-source cpu_features library.
//
// TODO(absl-team): Consider implementing a fallback of directly reading
// /proc/self/auxval.
#if defined(ABSL_INTERNAL_USE_ANDROID_GETAUXVAL)
#include <dlfcn.h>
static uint32_t GetAuxval(uint32_t hwcap_type) {
// NOLINTNEXTLINE(runtime/int)
typedef unsigned long (*getauxval_func_t)(unsigned long);
dlerror(); // Cleaning error state before calling dlopen.
void* libc_handle = dlopen("libc.so", RTLD_NOW);
if (!libc_handle) {
return 0;
}
uint32_t result = 0;
void* sym = dlsym(libc_handle, "getauxval");
if (sym) {
getauxval_func_t func;
memcpy(&func, &sym, sizeof(func));
result = static_cast<uint32_t>((*func)(hwcap_type));
}
dlclose(libc_handle);
return result;
}
#endif
namespace absl {
namespace random_internal {
// The default return at the end of the function might be unreachable depending
// on the configuration. Ignore that warning.
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code-return"
#endif
// CPUSupportsRandenHwAes returns whether the CPU is a microarchitecture
// which supports the crpyto/aes instructions or extensions necessary to use the
// accelerated RandenHwAes implementation.
//
// 1. For x86 it is sufficient to use the CPUID instruction to detect whether
// the cpu supports AES instructions. Done.
//
// Fon non-x86 it is much more complicated.
//
// 2. When ABSL_INTERNAL_USE_GETAUXVAL is defined, use getauxval() (either
// the direct c-library version, or the android probing version which loads
// libc), and read the hardware capability bits.
// This is based on the technique used by boringssl uses to detect
// cpu capabilities, and should allow us to enable crypto in the android
// builds where it is supported.
//
// 3. Use the default for the compiler architecture.
//
bool CPUSupportsRandenHwAes() {
#if defined(ABSL_INTERNAL_USE_X86_CPUID)
// 1. For x86: Use CPUID to detect the required AES instruction set.
int regs[4];
__cpuid(reinterpret_cast<int*>(regs), 1);
return regs[2] & (1 << 25); // AES
#elif defined(ABSL_INTERNAL_USE_GETAUXVAL)
// 2. Use getauxval() to read the hardware bits and determine
// cpu capabilities.
#define AT_HWCAP 16
#define AT_HWCAP2 26
#if defined(ABSL_ARCH_PPC)
// For Power / PPC: Expect that the cpu supports VCRYPTO
// See https://members.openpowerfoundation.org/document/dl/576
// VCRYPTO should be present in POWER8 >= 2.07.
// Uses Linux kernel constants from arch/powerpc/include/uapi/asm/cputable.h
static const uint32_t kVCRYPTO = 0x02000000;
const uint32_t hwcap = GetAuxval(AT_HWCAP2);
return (hwcap & kVCRYPTO) != 0;
#elif defined(ABSL_ARCH_ARM)
// For ARM: Require crypto+neon
// http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0500f/CIHBIBBA.html
// Uses Linux kernel constants from arch/arm64/include/asm/hwcap.h
static const uint32_t kNEON = 1 << 12;
uint32_t hwcap = GetAuxval(AT_HWCAP);
if ((hwcap & kNEON) == 0) {
return false;
}
// And use it again to detect AES.
static const uint32_t kAES = 1 << 0;
const uint32_t hwcap2 = GetAuxval(AT_HWCAP2);
return (hwcap2 & kAES) != 0;
#elif defined(ABSL_ARCH_AARCH64)
// For AARCH64: Require crypto+neon
// http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0500f/CIHBIBBA.html
static const uint32_t kNEON = 1 << 1;
static const uint32_t kAES = 1 << 3;
const uint32_t hwcap = GetAuxval(AT_HWCAP);
return ((hwcap & kNEON) != 0) && ((hwcap & kAES) != 0);
#endif
#else // ABSL_INTERNAL_USE_GETAUXVAL
// 3. By default, assume that the compiler default.
return ABSL_HAVE_ACCELERATED_AES ? true : false;
#endif
// NOTE: There are some other techniques that may be worth trying:
//
// * Use an environment variable: ABSL_RANDOM_USE_HWAES
//
// * Rely on compiler-generated target-based dispatch.
// Using x86/gcc it might look something like this:
//
// int __attribute__((target("aes"))) HasAes() { return 1; }
// int __attribute__((target("default"))) HasAes() { return 0; }
//
// This does not work on all architecture/compiler combinations.
//
// * On Linux consider reading /proc/cpuinfo and/or /proc/self/auxv.
// These files have lines which are easy to parse; for ARM/AARCH64 it is quite
// easy to find the Features: line and extract aes / neon. Likewise for
// PPC.
//
// * Fork a process and test for SIGILL:
//
// * Many architectures have instructions to read the ISA. Unfortunately
// most of those require that the code is running in ring 0 /
// protected-mode.
//
// There are several examples. e.g. Valgrind detects PPC ISA 2.07:
// https://github.com/lu-zero/valgrind/blob/master/none/tests/ppc64/test_isa_2_07_part1.c
//
// MRS <Xt>, ID_AA64ISAR0_EL1 ; Read ID_AA64ISAR0_EL1 into Xt
//
// uint64_t val;
// __asm __volatile("mrs %0, id_aa64isar0_el1" :"=&r" (val));
//
// * Use a CPUID-style heuristic database.
//
// * On Apple (__APPLE__), AES is available on Arm v8.
// https://stackoverflow.com/questions/45637888/how-to-determine-armv8-features-at-runtime-on-ios
}
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
} // namespace random_internal
} // namespace absl