The Tor Browser: media/libyuv/source/cpu_id.cc@b8a032363ba2 (annotated)

media/libyuv/source/cpu_id.cc@b8a032363ba2 (annotated)

media/libyuv/source/cpu_id.cc

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  *  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"
 #ifdef _MSC_VER
 #include <intrin.h>  // For __cpuidex()
 #endif
 #if !defined(__pnacl__) && !defined(__CLR_VER) && \
     !defined(__native_client__) && defined(_M_X64) && \
     defined(_MSC_VER) && (_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) && (_MSC_FULL_VER >= 160040219)
 #define SAFEBUFFERS __declspec(safebuffers)
 #else
 #define SAFEBUFFERS
 #endif
 // Low level cpuid for X86. Returns zeros on other CPUs.
 #if !defined(__pnacl__) && !defined(__CLR_VER) && \
     (defined(_M_IX86) || defined(_M_X64) || \
     defined(__i386__) || defined(__x86_64__))
 LIBYUV_API
 void CpuId(uint32 info_eax, uint32 info_ecx, uint32* cpu_info) {
 #if defined(_MSC_VER)
 #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
   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
 #else  // defined(_MSC_VER)
   uint32 info_ebx, info_edx;
   asm volatile (  // NOLINT
 #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)
 }
 #if !defined(__native_client__)
 #define HAS_XGETBV
 // X86 CPUs have xgetbv to detect OS saves high parts of ymm registers.
 int TestOsSaveYmm() {
   uint32 xcr0 = 0u;
 #if defined(_MSC_VER) && defined(_XCR_XFEATURE_ENABLED_MASK)
   xcr0 = (uint32)(_xgetbv(_XCR_XFEATURE_ENABLED_MASK));
 #elif defined(_MSC_VER) && defined(_M_IX86)
   __asm {
     xor        ecx, ecx    // xcr 0
     _asm _emit 0x0f _asm _emit 0x01 _asm _emit 0xd0  // For VS2010 and earlier.
     mov        xcr0, eax
   }
 #elif defined(__i386__) || defined(__x86_64__)
   asm(".byte 0x0f, 0x01, 0xd0" : "=a" (xcr0) : "c" (0) : "%edx");
 #endif  // defined(_MSC_VER)
   return((xcr0 & 6) == 6);  // Is ymm saved?
 }
 #endif  // !defined(__native_client__)
 #else
 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
 // 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) {
   FILE* f = fopen(cpuinfo_name, "r");
   if (f) {
     char cpuinfo_line[512];
     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;
         }
       }
     }
     fclose(f);
   }
   return 0;
 }
 #if defined(__mips__) && defined(__linux__)
 static int MipsCpuCaps(const char* search_string) {
   const char* file_name = "/proc/cpuinfo";
   char cpuinfo_line[256];
   FILE* f = NULL;
   if ((f = fopen(file_name, "r")) != NULL) {
     while (fgets(cpuinfo_line, sizeof(cpuinfo_line) - 1, f) != NULL) {
       if (strstr(cpuinfo_line, search_string) != NULL) {
         fclose(f);
         return kCpuHasMIPS_DSP;
       }
     }
     fclose(f);
   }
   /* Did not find string in the proc file, or not Linux ELF. */
   return 0;
 }
 #endif
 // CPU detect function for SIMD instruction sets.
 LIBYUV_API
 int cpu_info_ = kCpuInit;  // 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) {
 #if !defined(__pnacl__) && !defined(__CLR_VER) && defined(CPU_X86)
   uint32 cpu_info1[4] = { 0, 0, 0, 0 };
   uint32 cpu_info7[4] = { 0, 0, 0, 0 };
   CpuId(1, 0, cpu_info1);
   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
   if ((cpu_info1[2] & 0x18000000) == 0x18000000 &&  // AVX and OSSave
       TestOsSaveYmm()) {  // Saves YMM.
     cpu_info_ |= ((cpu_info7[1] & 0x00000020) ? kCpuHasAVX2 : 0) |
                  kCpuHasAVX;
   }
 #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;
   }
 #elif defined(__mips__) && defined(__linux__)
   // Linux mips parse text file for dsp detect.
   cpu_info_ = MipsCpuCaps("dsp");  // set kCpuHasMIPS_DSP.
 #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_DSP")) {
     cpu_info_ &= ~kCpuHasMIPS_DSP;
   }
   if (getenv("LIBYUV_DISABLE_MIPS_DSPR2")) {
     cpu_info_ &= ~kCpuHasMIPS_DSPR2;
   }
 #elif defined(__arm__)
 #if defined(__linux__) && (defined(__ARM_NEON__) || defined(LIBYUV_NEON)) && \
     !defined(__native_client__)
   // Linux arm parse text file for neon detect.
   cpu_info_ = ArmCpuCaps("/proc/cpuinfo");
 #elif defined(__ARM_NEON__) || defined(__native_client__)
   // gcc -mfpu=neon defines __ARM_NEON__
   // Enable Neon if you want support for Neon and Arm, and use MaskCpuFlags
   // to disable Neon on devices that do not have it.
   cpu_info_ = kCpuHasNEON;
 #endif
   cpu_info_ |= kCpuHasARM;
   if (TestEnv("LIBYUV_DISABLE_NEON")) {
     cpu_info_ &= ~kCpuHasNEON;
   }
 #endif  // __arm__
   if (TestEnv("LIBYUV_DISABLE_ASM")) {
     cpu_info_ = 0;
   }
   return cpu_info_;
 }
 LIBYUV_API
 void MaskCpuFlags(int enable_flags) {
   cpu_info_ = InitCpuFlags() & enable_flags;
 }
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif

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media/libyuv/source/cpu_id.cc@b8a032363ba2 (annotated)

media/libyuv/source/cpu_id.cc