libyuv/source/cpu_id.cc
Frank Barchard fae1a10545 Work around bug in xgetbv for Visual Studio.
xgetbv is generating bad code, falsely disabling AVX2 and AVX512.
disable optimization for the function affected on older versions of Visual C 32 bit.

R=brucedawson@chromium.org, dhrosa@google.com, harryjin@google.com
BUG=libyuv:529

Review URL: https://codereview.chromium.org/1503393004 .
2015-12-08 18:13:32 -08:00

305 lines
9.1 KiB
C++

/*
* Copyright 2011 The LibYuv 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 in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "libyuv/cpu_id.h"
#if (defined(_MSC_VER) && !defined(__clang__)) && !defined(__clang__)
#include <intrin.h> // For __cpuidex()
#endif
#if !defined(__pnacl__) && !defined(__CLR_VER) && \
!defined(__native_client__) && (defined(_M_IX86) || defined(_M_X64)) && \
defined(_MSC_VER) && !defined(__clang__) && (_MSC_FULL_VER >= 160040219)
#include <immintrin.h> // For _xgetbv()
#endif
#if !defined(__native_client__)
#include <stdlib.h> // For getenv()
#endif
// For ArmCpuCaps() but unittested on all platforms
#include <stdio.h>
#include <string.h>
#include "libyuv/basic_types.h" // For CPU_X86
#ifdef __cplusplus
namespace libyuv {
extern "C" {
#endif
// For functions that use the stack and have runtime checks for overflow,
// use SAFEBUFFERS to avoid additional check.
#if (defined(_MSC_VER) && !defined(__clang__)) && (_MSC_FULL_VER >= 160040219)
#define SAFEBUFFERS __declspec(safebuffers)
#else
#define SAFEBUFFERS
#endif
// Low level cpuid for X86.
#if (defined(_M_IX86) || defined(_M_X64) || \
defined(__i386__) || defined(__x86_64__)) && \
!defined(__pnacl__) && !defined(__CLR_VER)
LIBYUV_API
void CpuId(uint32 info_eax, uint32 info_ecx, uint32* cpu_info) {
#if defined(_MSC_VER) && !defined(__clang__)
// Visual C version uses intrinsic or inline x86 assembly.
#if (_MSC_FULL_VER >= 160040219)
__cpuidex((int*)(cpu_info), info_eax, info_ecx);
#elif defined(_M_IX86)
__asm {
mov eax, info_eax
mov ecx, info_ecx
mov edi, cpu_info
cpuid
mov [edi], eax
mov [edi + 4], ebx
mov [edi + 8], ecx
mov [edi + 12], edx
}
#else // Visual C but not x86
if (info_ecx == 0) {
__cpuid((int*)(cpu_info), info_eax);
} else {
cpu_info[3] = cpu_info[2] = cpu_info[1] = cpu_info[0] = 0;
}
#endif
// GCC version uses inline x86 assembly.
#else // defined(_MSC_VER) && !defined(__clang__)
uint32 info_ebx, info_edx;
asm volatile (
#if defined( __i386__) && defined(__PIC__)
// Preserve ebx for fpic 32 bit.
"mov %%ebx, %%edi \n"
"cpuid \n"
"xchg %%edi, %%ebx \n"
: "=D" (info_ebx),
#else
"cpuid \n"
: "=b" (info_ebx),
#endif // defined( __i386__) && defined(__PIC__)
"+a" (info_eax), "+c" (info_ecx), "=d" (info_edx));
cpu_info[0] = info_eax;
cpu_info[1] = info_ebx;
cpu_info[2] = info_ecx;
cpu_info[3] = info_edx;
#endif // defined(_MSC_VER) && !defined(__clang__)
}
#else // (defined(_M_IX86) || defined(_M_X64) ...
LIBYUV_API
void CpuId(uint32 eax, uint32 ecx, uint32* cpu_info) {
cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
}
#endif
// For VS2010 and earlier emit can be used:
// _asm _emit 0x0f _asm _emit 0x01 _asm _emit 0xd0 // For VS2010 and earlier.
// __asm {
// xor ecx, ecx // xcr 0
// xgetbv
// mov xcr0, eax
// }
// For VS2013 and earlier 32 bit, the _xgetbv(0) optimizer produces bad code.
// https://code.google.com/p/libyuv/issues/detail?id=529
#if defined(_M_IX86) && (_MSC_VER < 1900)
#pragma optimize("g", off)
#endif
#if (defined(_M_IX86) || defined(_M_X64) || \
defined(__i386__) || defined(__x86_64__)) && \
!defined(__pnacl__) && !defined(__CLR_VER) && !defined(__native_client__)
#define HAS_XGETBV
// X86 CPUs have xgetbv to detect OS saves high parts of ymm registers.
int GetXCR0() {
uint32 xcr0 = 0u;
#if (_MSC_FULL_VER >= 160040219)
xcr0 = (uint32)(_xgetbv(0)); // VS2010 SP1 required.
#elif defined(__i386__) || defined(__x86_64__)
uint32 xcr0 = 0u;
asm(".byte 0x0f, 0x01, 0xd0" : "=a" (xcr0) : "c" (0) : "%edx");
#endif // defined(__i386__) || defined(__x86_64__)
return xcr0;
}
#endif // defined(_M_IX86) || defined(_M_X64) ..
// Return optimization to previous setting.
#if defined(_M_IX86) && (_MSC_VER < 1900)
#pragma optimize("g", on)
#endif
// based on libvpx arm_cpudetect.c
// For Arm, but public to allow testing on any CPU
LIBYUV_API SAFEBUFFERS
int ArmCpuCaps(const char* cpuinfo_name) {
char cpuinfo_line[512];
FILE* f = fopen(cpuinfo_name, "r");
if (!f) {
// Assume Neon if /proc/cpuinfo is unavailable.
// This will occur for Chrome sandbox for Pepper or Render process.
return kCpuHasNEON;
}
while (fgets(cpuinfo_line, sizeof(cpuinfo_line) - 1, f)) {
if (memcmp(cpuinfo_line, "Features", 8) == 0) {
char* p = strstr(cpuinfo_line, " neon");
if (p && (p[5] == ' ' || p[5] == '\n')) {
fclose(f);
return kCpuHasNEON;
}
// aarch64 uses asimd for Neon.
p = strstr(cpuinfo_line, " asimd");
if (p && (p[6] == ' ' || p[6] == '\n')) {
fclose(f);
return kCpuHasNEON;
}
}
}
fclose(f);
return 0;
}
// CPU detect function for SIMD instruction sets.
LIBYUV_API
int cpu_info_ = 0; // cpu_info is not initialized yet.
// Test environment variable for disabling CPU features. Any non-zero value
// to disable. Zero ignored to make it easy to set the variable on/off.
#if !defined(__native_client__) && !defined(_M_ARM)
static LIBYUV_BOOL TestEnv(const char* name) {
const char* var = getenv(name);
if (var) {
if (var[0] != '0') {
return LIBYUV_TRUE;
}
}
return LIBYUV_FALSE;
}
#else // nacl does not support getenv().
static LIBYUV_BOOL TestEnv(const char*) {
return LIBYUV_FALSE;
}
#endif
LIBYUV_API SAFEBUFFERS
int InitCpuFlags(void) {
// TODO(fbarchard): swap kCpuInit logic so 0 means uninitialized.
int cpu_info = 0;
#if !defined(__pnacl__) && !defined(__CLR_VER) && defined(CPU_X86)
uint32 cpu_info0[4] = { 0, 0, 0, 0 };
uint32 cpu_info1[4] = { 0, 0, 0, 0 };
uint32 cpu_info7[4] = { 0, 0, 0, 0 };
CpuId(0, 0, cpu_info0);
CpuId(1, 0, cpu_info1);
if (cpu_info0[0] >= 7) {
CpuId(7, 0, cpu_info7);
}
cpu_info = ((cpu_info1[3] & 0x04000000) ? kCpuHasSSE2 : 0) |
((cpu_info1[2] & 0x00000200) ? kCpuHasSSSE3 : 0) |
((cpu_info1[2] & 0x00080000) ? kCpuHasSSE41 : 0) |
((cpu_info1[2] & 0x00100000) ? kCpuHasSSE42 : 0) |
((cpu_info7[1] & 0x00000200) ? kCpuHasERMS : 0) |
((cpu_info1[2] & 0x00001000) ? kCpuHasFMA3 : 0) |
kCpuHasX86;
#ifdef HAS_XGETBV
// AVX requires CPU has AVX, XSAVE and OSXSave for xgetbv
if ((cpu_info1[2] & 0x1c000000) == 0x1c000000 && // AVX and OSXSave
(GetXCR0() & 6) == 6) { // Test OD saves YMM registers
cpu_info |= ((cpu_info7[1] & 0x00000020) ? kCpuHasAVX2 : 0) | kCpuHasAVX;
// Detect AVX512bw
if ((GetXCR0() & 0xe0) == 0xe0) {
cpu_info |= (cpu_info7[1] & 0x40000000) ? kCpuHasAVX3 : 0;
}
}
#endif
// Environment variable overrides for testing.
if (TestEnv("LIBYUV_DISABLE_X86")) {
cpu_info &= ~kCpuHasX86;
}
if (TestEnv("LIBYUV_DISABLE_SSE2")) {
cpu_info &= ~kCpuHasSSE2;
}
if (TestEnv("LIBYUV_DISABLE_SSSE3")) {
cpu_info &= ~kCpuHasSSSE3;
}
if (TestEnv("LIBYUV_DISABLE_SSE41")) {
cpu_info &= ~kCpuHasSSE41;
}
if (TestEnv("LIBYUV_DISABLE_SSE42")) {
cpu_info &= ~kCpuHasSSE42;
}
if (TestEnv("LIBYUV_DISABLE_AVX")) {
cpu_info &= ~kCpuHasAVX;
}
if (TestEnv("LIBYUV_DISABLE_AVX2")) {
cpu_info &= ~kCpuHasAVX2;
}
if (TestEnv("LIBYUV_DISABLE_ERMS")) {
cpu_info &= ~kCpuHasERMS;
}
if (TestEnv("LIBYUV_DISABLE_FMA3")) {
cpu_info &= ~kCpuHasFMA3;
}
if (TestEnv("LIBYUV_DISABLE_AVX3")) {
cpu_info &= ~kCpuHasAVX3;
}
#endif
#if defined(__mips__) && defined(__linux__)
#if defined(__mips_dspr2)
cpu_info |= kCpuHasMIPS_DSPR2;
#endif
cpu_info |= kCpuHasMIPS;
if (getenv("LIBYUV_DISABLE_MIPS")) {
cpu_info &= ~kCpuHasMIPS;
}
if (getenv("LIBYUV_DISABLE_MIPS_DSPR2")) {
cpu_info &= ~kCpuHasMIPS_DSPR2;
}
#endif
#if defined(__arm__) || defined(__aarch64__)
// gcc -mfpu=neon defines __ARM_NEON__
// __ARM_NEON__ generates code that requires Neon. NaCL also requires Neon.
// For Linux, /proc/cpuinfo can be tested but without that assume Neon.
#if defined(__ARM_NEON__) || defined(__native_client__) || !defined(__linux__)
cpu_info = kCpuHasNEON;
// For aarch64(arm64), /proc/cpuinfo's feature is not complete, e.g. no neon
// flag in it.
// So for aarch64, neon enabling is hard coded here.
#endif
#if defined(__aarch64__)
cpu_info = kCpuHasNEON;
#else
// Linux arm parse text file for neon detect.
cpu_info = ArmCpuCaps("/proc/cpuinfo");
#endif
cpu_info |= kCpuHasARM;
if (TestEnv("LIBYUV_DISABLE_NEON")) {
cpu_info &= ~kCpuHasNEON;
}
#endif // __arm__
if (TestEnv("LIBYUV_DISABLE_ASM")) {
cpu_info = 0;
}
cpu_info |= kCpuInitialized;
cpu_info_ = cpu_info;
return cpu_info;
}
// Note that use of this function is not thread safe.
LIBYUV_API
void MaskCpuFlags(int enable_flags) {
cpu_info_ = InitCpuFlags() & enable_flags;
}
#ifdef __cplusplus
} // extern "C"
} // namespace libyuv
#endif