components/nacl/renderer/platform_info.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/cpu.h"
   6 #include "base/logging.h"
   7 #include "base/strings/string_util.h"
   8 #if defined(OS_WIN)
   9 #include "base/win/windows_version.h"
  10 #endif
  11
  12 namespace nacl {
  13
  14 const char* GetSandboxArch() {
  15 #if defined(ARCH_CPU_ARM_FAMILY)
  16   return "arm";
  17 #elif defined(ARCH_CPU_MIPS_FAMILY)
  18   return "mips32";
  19 #elif defined(ARCH_CPU_X86_FAMILY)
  20
  21 #if defined(OS_WIN)
  22   // We have to check the host architecture on Windows.
  23   // See sandbox_isa.h for an explanation why.
  24   if (base::win::OSInfo::GetInstance()->architecture() ==
  25       base::win::OSInfo::X64_ARCHITECTURE)
  26     return "x86-64";
  27   else
  28     return "x86-32";
  29 #elif ARCH_CPU_64_BITS
  30   return "x86-64";
  31 #else
  32   return "x86-32";
  33 #endif  // defined(OS_WIN)
  34
  35 #else
  36 #error Architecture not supported.
  37 #endif
  38 }
  39
  40 std::string GetCpuFeatures() {
  41   // PNaCl's translator from pexe to nexe can be told exactly what
  42   // capabilities the user's machine has because the pexe to nexe
  43   // translation is specific to the machine, and CPU information goes
  44   // into the translation cache. This allows the translator to generate
  45   // faster code.
  46   //
  47   // Care must be taken to avoid instructions which aren't supported by
  48   // the NaCl sandbox. Ideally the translator would do this, but there's
  49   // no point in not doing the whitelist here.
  50   //
  51   // TODO(jfb) Some features are missing, either because the NaCl
  52   //           sandbox doesn't support them, because base::CPU doesn't
  53   //           detect them, or because they don't help vector shuffles
  54   //           (and we omit them because it simplifies testing). Add the
  55   //           other features.
  56   //
  57   // TODO(jfb) The following is x86-specific. The base::CPU class
  58   //           doesn't handle other architectures very well, and we
  59   //           should at least detect the presence of ARM's integer
  60   //           divide.
  61   std::vector<std::string> features;
  62   base::CPU cpu;
  63
  64   // On x86, SSE features are ordered: the most recent one implies the
  65   // others. Care is taken here to only specify the latest SSE version,
  66   // whereas non-SSE features don't follow this model: POPCNT is
  67   // effectively always implied by SSE4.2 but has to be specified
  68   // separately.
  69   //
  70   // TODO: AVX2, AVX, SSE 4.2.
  71   if (cpu.has_sse41()) features.push_back("+sse4.1");
  72   // TODO: SSE 4A, SSE 4.
  73   else if (cpu.has_ssse3()) features.push_back("+ssse3");
  74   // TODO: SSE 3
  75   else if (cpu.has_sse2()) features.push_back("+sse2");
  76
  77   // TODO: AES, POPCNT, LZCNT, ...
  78   return JoinString(features, ',');
  79 }
  80
  81 }  // namespace nacl