774 lines
23 KiB
C++
774 lines
23 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Copyright (C) 2019 Intel Corporation.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 3 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL3 included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 3 requirements
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** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 2.0 or (at your option) the GNU General
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** Public license version 3 or any later version approved by the KDE Free
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** Qt Foundation. The licenses are as published by the Free Software
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** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-2.0.html and
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** https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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// we need ICC to define the prototype for _rdseed64_step
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#define __INTEL_COMPILER_USE_INTRINSIC_PROTOTYPES
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#include "qsimd_p.h"
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#include "qalgorithms.h"
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#include <QByteArray>
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#include <stdio.h>
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#ifdef Q_OS_LINUX
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# include "../testlib/3rdparty/valgrind_p.h"
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#endif
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#if defined(Q_OS_WIN)
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# if !defined(Q_CC_GNU)
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# include <intrin.h>
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# endif
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#elif defined(Q_OS_LINUX) && (defined(Q_PROCESSOR_ARM) || defined(Q_PROCESSOR_MIPS_32))
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#include "private/qcore_unix_p.h"
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// the kernel header definitions for HWCAP_*
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// (the ones we need/may need anyway)
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// copied from <asm/hwcap.h> (ARM)
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#define HWCAP_CRUNCH 1024
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#define HWCAP_THUMBEE 2048
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#define HWCAP_NEON 4096
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#define HWCAP_VFPv3 8192
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#define HWCAP_VFPv3D16 16384
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// copied from <asm/hwcap.h> (ARM):
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#define HWCAP2_CRC32 (1 << 4)
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// copied from <asm/hwcap.h> (Aarch64)
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#define HWCAP_CRC32 (1 << 7)
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// copied from <linux/auxvec.h>
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#define AT_HWCAP 16 /* arch dependent hints at CPU capabilities */
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#define AT_HWCAP2 26 /* extension of AT_HWCAP */
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#elif defined(Q_CC_GHS)
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#include <INTEGRITY_types.h>
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#endif
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QT_BEGIN_NAMESPACE
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/*
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* Use kdesdk/scripts/generate_string_table.pl to update the table below. Note
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* we remove the terminating -1 that the script adds.
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*/
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// begin generated
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#if defined(Q_PROCESSOR_ARM)
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/* Data:
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neon
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crc32
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*/
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static const char features_string[] =
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" neon\0"
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" crc32\0"
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"\0";
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static const int features_indices[] = { 0, 6 };
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#elif defined(Q_PROCESSOR_MIPS)
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/* Data:
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dsp
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dspr2
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*/
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static const char features_string[] =
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" dsp\0"
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" dspr2\0"
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"\0";
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static const int features_indices[] = {
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0, 5
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};
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#elif defined(Q_PROCESSOR_X86)
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# include "qsimd_x86.cpp" // generated by util/x86simdgen
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#else
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static const char features_string[] = "";
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static const int features_indices[] = { };
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#endif
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// end generated
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#if defined (Q_OS_NACL)
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static inline uint detectProcessorFeatures()
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{
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return 0;
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}
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#elif defined(Q_PROCESSOR_ARM)
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static inline quint64 detectProcessorFeatures()
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{
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quint64 features = 0;
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#if defined(Q_OS_LINUX)
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# if defined(Q_PROCESSOR_ARM_V8) && defined(Q_PROCESSOR_ARM_64)
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features |= CpuFeatureNEON; // NEON is always available on ARMv8 64bit.
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# endif
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int auxv = qt_safe_open("/proc/self/auxv", O_RDONLY);
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if (auxv != -1) {
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unsigned long vector[64];
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int nread;
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while (features == 0) {
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nread = qt_safe_read(auxv, (char *)vector, sizeof vector);
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if (nread <= 0) {
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// EOF or error
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break;
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}
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int max = nread / (sizeof vector[0]);
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for (int i = 0; i < max; i += 2) {
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if (vector[i] == AT_HWCAP) {
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# if defined(Q_PROCESSOR_ARM_V8) && defined(Q_PROCESSOR_ARM_64)
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// For Aarch64:
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if (vector[i+1] & HWCAP_CRC32)
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features |= CpuFeatureCRC32;
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# endif
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// Aarch32, or ARMv7 or before:
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if (vector[i+1] & HWCAP_NEON)
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features |= CpuFeatureNEON;
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}
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# if defined(Q_PROCESSOR_ARM_32)
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// For Aarch32:
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if (vector[i] == AT_HWCAP2) {
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if (vector[i+1] & HWCAP2_CRC32)
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features |= CpuFeatureCRC32;
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}
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# endif
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}
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}
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qt_safe_close(auxv);
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return features;
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}
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// fall back if /proc/self/auxv wasn't found
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#endif
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#if defined(__ARM_NEON__)
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features |= CpuFeatureNEON;
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#endif
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#if defined(__ARM_FEATURE_CRC32)
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features |= CpuFeatureCRC32;
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#endif
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return features;
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}
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#elif defined(Q_PROCESSOR_X86)
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#ifdef Q_PROCESSOR_X86_32
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# define PICreg "%%ebx"
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#else
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# define PICreg "%%rbx"
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#endif
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static bool checkRdrndWorks() noexcept;
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static int maxBasicCpuidSupported()
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{
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#if defined(Q_CC_EMSCRIPTEN)
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return 6; // All features supported by Emscripten
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#elif defined(Q_CC_GNU)
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qregisterint tmp1;
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# if Q_PROCESSOR_X86 < 5
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// check if the CPUID instruction is supported
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long cpuid_supported;
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asm ("pushf\n"
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"pop %0\n"
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"mov %0, %1\n"
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"xor $0x00200000, %0\n"
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"push %0\n"
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"popf\n"
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"pushf\n"
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"pop %0\n"
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"xor %1, %0\n" // %eax is now 0 if CPUID is not supported
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: "=a" (cpuid_supported), "=r" (tmp1)
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);
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if (!cpuid_supported)
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return 0;
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# endif
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int result;
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asm ("xchg " PICreg", %1\n"
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"cpuid\n"
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"xchg " PICreg", %1\n"
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: "=&a" (result), "=&r" (tmp1)
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: "0" (0)
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: "ecx", "edx");
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return result;
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#elif defined(Q_OS_WIN)
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// Use the __cpuid function; if the CPUID instruction isn't supported, it will return 0
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int info[4];
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__cpuid(info, 0);
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return info[0];
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#elif defined(Q_CC_GHS)
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unsigned int info[4];
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__CPUID(0, info);
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return info[0];
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#else
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return 0;
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#endif
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}
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static void cpuidFeatures01(uint &ecx, uint &edx)
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{
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#if defined(Q_CC_GNU) && !defined(Q_CC_EMSCRIPTEN)
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qregisterint tmp1;
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asm ("xchg " PICreg", %2\n"
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"cpuid\n"
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"xchg " PICreg", %2\n"
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: "=&c" (ecx), "=&d" (edx), "=&r" (tmp1)
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: "a" (1));
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#elif defined(Q_OS_WIN)
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int info[4];
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__cpuid(info, 1);
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ecx = info[2];
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edx = info[3];
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#elif defined(Q_CC_GHS)
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unsigned int info[4];
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__CPUID(1, info);
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ecx = info[2];
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edx = info[3];
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#else
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Q_UNUSED(ecx);
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Q_UNUSED(edx);
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#endif
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}
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#ifdef Q_OS_WIN
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inline void __cpuidex(int info[4], int, __int64) { memset(info, 0, 4*sizeof(int));}
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#endif
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static void cpuidFeatures07_00(uint &ebx, uint &ecx, uint &edx)
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{
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#if defined(Q_CC_GNU) && !defined(Q_CC_EMSCRIPTEN)
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qregisteruint rbx; // in case it's 64-bit
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qregisteruint rcx = 0;
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qregisteruint rdx = 0;
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asm ("xchg " PICreg", %0\n"
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"cpuid\n"
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"xchg " PICreg", %0\n"
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: "=&r" (rbx), "+&c" (rcx), "+&d" (rdx)
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: "a" (7));
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ebx = rbx;
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ecx = rcx;
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edx = rdx;
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#elif defined(Q_OS_WIN)
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int info[4];
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__cpuidex(info, 7, 0);
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ebx = info[1];
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ecx = info[2];
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edx = info[3];
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#elif defined(Q_CC_GHS)
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unsigned int info[4];
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__CPUIDEX(7, 0, info);
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ebx = info[1];
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ecx = info[2];
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edx = info[3];
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#else
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Q_UNUSED(ebx);
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Q_UNUSED(ecx);
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Q_UNUSED(edx);
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#endif
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}
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#if defined(Q_OS_WIN) && !(defined(Q_CC_GNU) || defined(Q_CC_GHS))
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// fallback overload in case this intrinsic does not exist: unsigned __int64 _xgetbv(unsigned int);
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inline quint64 _xgetbv(__int64) { return 0; }
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#endif
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static void xgetbv(uint in, uint &eax, uint &edx)
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{
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#if (defined(Q_CC_GNU) && !defined(Q_CC_EMSCRIPTEN)) || defined(Q_CC_GHS)
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asm (".byte 0x0F, 0x01, 0xD0" // xgetbv instruction
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: "=a" (eax), "=d" (edx)
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: "c" (in));
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#elif defined(Q_OS_WIN)
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quint64 result = _xgetbv(in);
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eax = result;
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edx = result >> 32;
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#else
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Q_UNUSED(in);
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Q_UNUSED(eax);
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Q_UNUSED(edx);
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#endif
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}
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// Flags from the XCR0 state register
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enum XCR0Flags {
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X87 = 1 << 0,
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XMM0_15 = 1 << 1,
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YMM0_15Hi128 = 1 << 2,
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BNDRegs = 1 << 3,
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BNDCSR = 1 << 4,
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OpMask = 1 << 5,
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ZMM0_15Hi256 = 1 << 6,
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ZMM16_31 = 1 << 7,
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SSEState = XMM0_15,
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AVXState = XMM0_15 | YMM0_15Hi128,
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AVX512State = AVXState | OpMask | ZMM0_15Hi256 | ZMM16_31
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};
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static quint64 adjustedXcr0(quint64 xcr0)
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{
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/*
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* Some OSes hide their capability of context-switching the AVX512 state in
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* the XCR0 register. They do that so the first time we execute an
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* instruction that may access the AVX512 state (requiring the EVEX prefix)
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* they allocate the necessary context switch space.
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*
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* This behavior is deprecated with the XFD (Extended Feature Disable)
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* register, but we can't change existing OSes.
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*/
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#ifdef Q_OS_DARWIN
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// from <machine/cpu_capabilities.h> in xnu
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// <https://github.com/apple/darwin-xnu/blob/xnu-4903.221.2/osfmk/i386/cpu_capabilities.h>
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constexpr quint64 kHasAVX512F = Q_UINT64_C(0x0000004000000000);
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constexpr quintptr commpage = sizeof(void *) > 4 ? Q_UINT64_C(0x00007fffffe00000) : 0xffff0000;
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constexpr quintptr cpu_capabilities64 = commpage + 0x10;
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quint64 capab = *reinterpret_cast<quint64 *>(cpu_capabilities64);
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if (capab & kHasAVX512F)
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xcr0 |= AVX512State;
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#endif
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return xcr0;
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}
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static quint64 detectProcessorFeatures()
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{
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static const quint64 AllAVX2 = CpuFeatureAVX2 | AllAVX512;
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static const quint64 AllAVX = CpuFeatureAVX | AllAVX2;
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quint64 features = 0;
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int cpuidLevel = maxBasicCpuidSupported();
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#if Q_PROCESSOR_X86 < 5
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if (cpuidLevel < 1)
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return 0;
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#else
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Q_ASSERT(cpuidLevel >= 1);
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#endif
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uint results[X86CpuidMaxLeaf] = {};
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cpuidFeatures01(results[Leaf1ECX], results[Leaf1EDX]);
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if (cpuidLevel >= 7)
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cpuidFeatures07_00(results[Leaf7_0EBX], results[Leaf7_0ECX], results[Leaf7_0EDX]);
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// populate our feature list
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for (uint i = 0; i < sizeof(x86_locators) / sizeof(x86_locators[0]); ++i) {
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uint word = x86_locators[i] / 32;
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uint bit = 1U << (x86_locators[i] % 32);
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quint64 feature = Q_UINT64_C(1) << (i + 1);
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if (results[word] & bit)
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features |= feature;
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}
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// now check the AVX state
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quint64 xcr0 = 0;
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if (results[Leaf1ECX] & (1u << 27)) {
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// XGETBV enabled
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uint xgetbvA = 0, xgetbvD = 0;
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xgetbv(0, xgetbvA, xgetbvD);
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xcr0 = xgetbvA;
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if (sizeof(XCR0Flags) > sizeof(xgetbvA))
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xcr0 |= quint64(xgetbvD) << 32;
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xcr0 = adjustedXcr0(xcr0);
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}
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if ((xcr0 & AVXState) != AVXState) {
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// support for YMM registers is disabled, disable all AVX
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features &= ~AllAVX;
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} else if ((xcr0 & AVX512State) != AVX512State) {
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// support for ZMM registers or mask registers is disabled, disable all AVX512
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features &= ~AllAVX512;
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}
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if (features & CpuFeatureRDRND && !checkRdrndWorks())
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features &= ~(CpuFeatureRDRND | CpuFeatureRDSEED);
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return features;
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}
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#elif defined(Q_PROCESSOR_MIPS_32)
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#if defined(Q_OS_LINUX)
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//
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// Do not use QByteArray: it could use SIMD instructions itself at
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// some point, thus creating a recursive dependency. Instead, use a
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// QSimpleBuffer, which has the bare minimum needed to use memory
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// dynamically and read lines from /proc/cpuinfo of arbitrary sizes.
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//
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struct QSimpleBuffer
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{
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static const int chunk_size = 256;
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char *data;
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unsigned alloc;
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unsigned size;
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QSimpleBuffer() : data(nullptr), alloc(0), size(0) { }
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~QSimpleBuffer() { ::free(data); }
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void resize(unsigned newsize)
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{
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if (newsize > alloc) {
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unsigned newalloc = chunk_size * ((newsize / chunk_size) + 1);
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if (newalloc < newsize)
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newalloc = newsize;
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if (newalloc != alloc) {
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data = static_cast<char *>(::realloc(data, newalloc));
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alloc = newalloc;
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}
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}
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size = newsize;
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}
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void append(const QSimpleBuffer &other, unsigned appendsize)
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{
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unsigned oldsize = size;
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resize(oldsize + appendsize);
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::memcpy(data + oldsize, other.data, appendsize);
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}
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void popleft(unsigned amount)
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{
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if (amount >= size)
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return resize(0);
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size -= amount;
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::memmove(data, data + amount, size);
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}
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char *cString()
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{
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if (!alloc)
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resize(1);
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return (data[size] = '\0', data);
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}
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};
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//
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// Uses a scratch "buffer" (which must be used for all reads done in the
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// same file descriptor) to read chunks of data from a file, to read
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// one line at a time. Lines include the trailing newline character ('\n').
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// On EOF, line.size is zero.
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//
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static void bufReadLine(int fd, QSimpleBuffer &line, QSimpleBuffer &buffer)
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{
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for (;;) {
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char *newline = static_cast<char *>(::memchr(buffer.data, '\n', buffer.size));
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if (newline) {
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unsigned piece_size = newline - buffer.data + 1;
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line.append(buffer, piece_size);
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buffer.popleft(piece_size);
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line.resize(line.size - 1);
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return;
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}
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if (buffer.size + QSimpleBuffer::chunk_size > buffer.alloc) {
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int oldsize = buffer.size;
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buffer.resize(buffer.size + QSimpleBuffer::chunk_size);
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buffer.size = oldsize;
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}
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ssize_t read_bytes =
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::qt_safe_read(fd, buffer.data + buffer.size, QSimpleBuffer::chunk_size);
|
|
if (read_bytes > 0)
|
|
buffer.size += read_bytes;
|
|
else
|
|
return;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Checks if any line with a given prefix from /proc/cpuinfo contains
|
|
// a certain string, surrounded by spaces.
|
|
//
|
|
static bool procCpuinfoContains(const char *prefix, const char *string)
|
|
{
|
|
int cpuinfo_fd = ::qt_safe_open("/proc/cpuinfo", O_RDONLY);
|
|
if (cpuinfo_fd == -1)
|
|
return false;
|
|
|
|
unsigned string_len = ::strlen(string);
|
|
unsigned prefix_len = ::strlen(prefix);
|
|
QSimpleBuffer line, buffer;
|
|
bool present = false;
|
|
do {
|
|
line.resize(0);
|
|
bufReadLine(cpuinfo_fd, line, buffer);
|
|
char *colon = static_cast<char *>(::memchr(line.data, ':', line.size));
|
|
if (colon && line.size > prefix_len + string_len) {
|
|
if (!::strncmp(prefix, line.data, prefix_len)) {
|
|
// prefix matches, next character must be ':' or space
|
|
if (line.data[prefix_len] == ':' || ::isspace(line.data[prefix_len])) {
|
|
// Does it contain the string?
|
|
char *found = ::strstr(line.cString(), string);
|
|
if (found && ::isspace(found[-1]) &&
|
|
(::isspace(found[string_len]) || found[string_len] == '\0')) {
|
|
present = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} while (line.size);
|
|
|
|
::qt_safe_close(cpuinfo_fd);
|
|
return present;
|
|
}
|
|
#endif
|
|
|
|
static inline quint64 detectProcessorFeatures()
|
|
{
|
|
// NOTE: MIPS 74K cores are the only ones supporting DSPr2.
|
|
quint64 flags = 0;
|
|
|
|
#if defined __mips_dsp
|
|
flags |= CpuFeatureDSP;
|
|
# if defined __mips_dsp_rev && __mips_dsp_rev >= 2
|
|
flags |= CpuFeatureDSPR2;
|
|
# elif defined(Q_OS_LINUX)
|
|
if (procCpuinfoContains("cpu model", "MIPS 74Kc") || procCpuinfoContains("cpu model", "MIPS 74Kf"))
|
|
flags |= CpuFeatureDSPR2;
|
|
# endif
|
|
#elif defined(Q_OS_LINUX)
|
|
if (procCpuinfoContains("ASEs implemented", "dsp")) {
|
|
flags |= CpuFeatureDSP;
|
|
if (procCpuinfoContains("cpu model", "MIPS 74Kc") || procCpuinfoContains("cpu model", "MIPS 74Kf"))
|
|
flags |= CpuFeatureDSPR2;
|
|
}
|
|
#endif
|
|
|
|
return flags;
|
|
}
|
|
|
|
#else
|
|
static inline uint detectProcessorFeatures()
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static const int features_count = (sizeof features_indices) / (sizeof features_indices[0]);
|
|
|
|
// record what CPU features were enabled by default in this Qt build
|
|
static const quint64 minFeature = qCompilerCpuFeatures;
|
|
|
|
#ifdef Q_ATOMIC_INT64_IS_SUPPORTED
|
|
Q_CORE_EXPORT QBasicAtomicInteger<quint64> qt_cpu_features[1] = { Q_BASIC_ATOMIC_INITIALIZER(0) };
|
|
#else
|
|
Q_CORE_EXPORT QBasicAtomicInteger<unsigned> qt_cpu_features[2] = { Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0) };
|
|
#endif
|
|
|
|
quint64 qDetectCpuFeatures()
|
|
{
|
|
quint64 f = detectProcessorFeatures();
|
|
QByteArray disable = qgetenv("QT_NO_CPU_FEATURE");
|
|
if (!disable.isEmpty()) {
|
|
disable.prepend(' ');
|
|
for (int i = 0; i < features_count; ++i) {
|
|
if (disable.contains(features_string + features_indices[i]))
|
|
f &= ~(Q_UINT64_C(1) << i);
|
|
}
|
|
}
|
|
|
|
#ifdef RUNNING_ON_VALGRIND
|
|
bool runningOnValgrind = RUNNING_ON_VALGRIND;
|
|
#else
|
|
bool runningOnValgrind = false;
|
|
#endif
|
|
if (Q_UNLIKELY(!runningOnValgrind && minFeature != 0 && (f & minFeature) != minFeature)) {
|
|
quint64 missing = minFeature & ~f;
|
|
fprintf(stderr, "Incompatible processor. This Qt build requires the following features:\n ");
|
|
for (int i = 0; i < features_count; ++i) {
|
|
if (missing & (Q_UINT64_C(1) << i))
|
|
fprintf(stderr, "%s", features_string + features_indices[i]);
|
|
}
|
|
fprintf(stderr, "\n");
|
|
fflush(stderr);
|
|
qFatal("Aborted. Incompatible processor: missing feature 0x%llx -%s.", missing,
|
|
features_string + features_indices[qCountTrailingZeroBits(missing)]);
|
|
}
|
|
|
|
qt_cpu_features[0].storeRelaxed(f | quint32(QSimdInitialized));
|
|
#ifndef Q_ATOMIC_INT64_IS_SUPPORTED
|
|
qt_cpu_features[1].storeRelaxed(f >> 32);
|
|
#endif
|
|
return f;
|
|
}
|
|
|
|
void qDumpCPUFeatures()
|
|
{
|
|
quint64 features = qCpuFeatures() & ~quint64(QSimdInitialized);
|
|
printf("Processor features: ");
|
|
for (int i = 0; i < features_count; ++i) {
|
|
if (features & (Q_UINT64_C(1) << i))
|
|
printf("%s%s", features_string + features_indices[i],
|
|
minFeature & (Q_UINT64_C(1) << i) ? "[required]" : "");
|
|
}
|
|
if ((features = (qCompilerCpuFeatures & ~features))) {
|
|
printf("\n!!!!!!!!!!!!!!!!!!!!\n!!! Missing required features:");
|
|
for (int i = 0; i < features_count; ++i) {
|
|
if (features & (Q_UINT64_C(1) << i))
|
|
printf("%s", features_string + features_indices[i]);
|
|
}
|
|
printf("\n!!! Applications will likely crash with \"Invalid Instruction\"\n!!!!!!!!!!!!!!!!!!!!");
|
|
}
|
|
puts("");
|
|
}
|
|
|
|
#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
|
|
|
|
# ifdef Q_PROCESSOR_X86_64
|
|
# define _rdrandXX_step _rdrand64_step
|
|
# define _rdseedXX_step _rdseed64_step
|
|
# else
|
|
# define _rdrandXX_step _rdrand32_step
|
|
# define _rdseedXX_step _rdseed32_step
|
|
# endif
|
|
|
|
// The parameter to _rdrand64_step & _rdseed64_step is unsigned long long for
|
|
// Clang and GCC but unsigned __int64 for MSVC and ICC, which is unsigned long
|
|
// long on Windows, but unsigned long on Linux.
|
|
namespace {
|
|
template <typename F> struct ExtractParameter;
|
|
template <typename T> struct ExtractParameter<int (T *)> { using Type = T; };
|
|
using randuint = ExtractParameter<decltype(_rdrandXX_step)>::Type;
|
|
}
|
|
|
|
# if QT_COMPILER_SUPPORTS_HERE(RDSEED)
|
|
static QT_FUNCTION_TARGET(RDSEED) unsigned *qt_random_rdseed(unsigned *ptr, unsigned *end) noexcept
|
|
{
|
|
// Unlike for the RDRAND code below, the Intel whitepaper describing the
|
|
// use of the RDSEED instruction indicates we should not retry in a loop.
|
|
// If the independent bit generator used by RDSEED is out of entropy, it
|
|
// may take time to replenish.
|
|
// https://software.intel.com/en-us/articles/intel-digital-random-number-generator-drng-software-implementation-guide
|
|
while (ptr + sizeof(randuint) / sizeof(*ptr) <= end) {
|
|
if (_rdseedXX_step(reinterpret_cast<randuint *>(ptr)) == 0)
|
|
goto out;
|
|
ptr += sizeof(randuint) / sizeof(*ptr);
|
|
}
|
|
|
|
if (sizeof(*ptr) != sizeof(randuint) && ptr != end) {
|
|
if (_rdseed32_step(ptr) == 0)
|
|
goto out;
|
|
++ptr;
|
|
}
|
|
|
|
out:
|
|
return ptr;
|
|
}
|
|
# else
|
|
static unsigned *qt_random_rdseed(unsigned *ptr, unsigned *)
|
|
{
|
|
return ptr;
|
|
}
|
|
# endif
|
|
|
|
static QT_FUNCTION_TARGET(RDRND) unsigned *qt_random_rdrnd(unsigned *ptr, unsigned *end) noexcept
|
|
{
|
|
int retries = 10;
|
|
while (ptr + sizeof(randuint)/sizeof(*ptr) <= end) {
|
|
if (_rdrandXX_step(reinterpret_cast<randuint *>(ptr)))
|
|
ptr += sizeof(randuint)/sizeof(*ptr);
|
|
else if (--retries == 0)
|
|
goto out;
|
|
}
|
|
|
|
while (sizeof(*ptr) != sizeof(randuint) && ptr != end) {
|
|
bool ok = _rdrand32_step(ptr);
|
|
if (!ok && --retries)
|
|
continue;
|
|
if (ok)
|
|
++ptr;
|
|
break;
|
|
}
|
|
|
|
out:
|
|
return ptr;
|
|
}
|
|
|
|
static QT_FUNCTION_TARGET(RDRND) Q_DECL_COLD_FUNCTION bool checkRdrndWorks() noexcept
|
|
{
|
|
/*
|
|
* Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
|
|
* failing random generation instruction, which always returns
|
|
* 0xffffffff, even when generation was "successful".
|
|
*
|
|
* This code checks if hardware random generator generates four consecutive
|
|
* equal numbers. If it does, then we probably have a failing one and
|
|
* should disable it completely.
|
|
*
|
|
* https://bugreports.qt.io/browse/QTBUG-69423
|
|
*/
|
|
constexpr qsizetype TestBufferSize = 4;
|
|
unsigned testBuffer[TestBufferSize] = {};
|
|
|
|
unsigned *end = qt_random_rdrnd(testBuffer, testBuffer + TestBufferSize);
|
|
if (end < testBuffer + 3) {
|
|
// Random generation didn't produce enough data for us to make a
|
|
// determination whether it's working or not. Assume it isn't, but
|
|
// don't print a warning.
|
|
return false;
|
|
}
|
|
|
|
// Check the results for equality
|
|
if (testBuffer[0] == testBuffer[1]
|
|
&& testBuffer[0] == testBuffer[2]
|
|
&& (end < testBuffer + TestBufferSize || testBuffer[0] == testBuffer[3])) {
|
|
fprintf(stderr, "WARNING: CPU random generator seem to be failing, "
|
|
"disabling hardware random number generation\n"
|
|
"WARNING: RDRND generated:");
|
|
for (unsigned *ptr = testBuffer; ptr < end; ++ptr)
|
|
fprintf(stderr, " 0x%x", *ptr);
|
|
fprintf(stderr, "\n");
|
|
return false;
|
|
}
|
|
|
|
// We're good
|
|
return true;
|
|
}
|
|
|
|
QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) noexcept
|
|
{
|
|
unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
|
|
unsigned *end = ptr + count;
|
|
|
|
if (qCpuHasFeature(RDSEED))
|
|
ptr = qt_random_rdseed(ptr, end);
|
|
|
|
// fill the buffer with RDRND if RDSEED didn't
|
|
ptr = qt_random_rdrnd(ptr, end);
|
|
return ptr - reinterpret_cast<unsigned *>(buffer);
|
|
}
|
|
#elif defined(Q_PROCESSOR_X86) && !defined(Q_OS_NACL) && !defined(Q_PROCESSOR_ARM)
|
|
static bool checkRdrndWorks() noexcept { return false; }
|
|
#endif // Q_PROCESSOR_X86 && RDRND
|
|
|
|
QT_END_NAMESPACE
|