Use the pnacl-clang toolchain for (P)NaCL builds

src/base/cpu.cc

 // Copyright 2013 the V8 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.
 
 #include "src/base/cpu.h"
 
 #if V8_LIBC_MSVCRT
 #include <intrin.h>  // __cpuid()
 #endif
 #if V8_OS_POSIX
@@ skipping 11 matching lines @@
 #include <algorithm>
 
 #include "src/base/logging.h"
 #if V8_OS_WIN
 #include "src/base/win32-headers.h"  // NOLINT
 #endif
 
 namespace v8 {
 namespace base {
 
-#if V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
+#if defined(__pnacl__)
+// Portable host shouldn't do feature detection.
+#elif V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
 
 // Define __cpuid() for non-MSVC libraries.
 #if !V8_LIBC_MSVCRT
 
 static V8_INLINE void __cpuid(int cpu_info[4], int info_type) {
 #if defined(__i386__) && defined(__pic__)
   // Make sure to preserve ebx, which contains the pointer
   // to the GOT in case we're generating PIC.
   __asm__ volatile (
     "mov %%ebx, %%edi\n\t"
@@ skipping 240 matching lines @@
              has_sse41_(false),
              has_sse42_(false),
              has_idiva_(false),
              has_neon_(false),
              has_thumb2_(false),
              has_vfp_(false),
              has_vfp3_(false),
              has_vfp3_d32_(false),
              is_fp64_mode_(false) {
   memcpy(vendor_, "Unknown", 8);
-#if V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
+#if defined(__pnacl__)
+// Portable host shouldn't do feature detection.
+// TODO(jfb): Remove the hardcoded ARM simulator flags in the build, and
+// hardcode them here instead.
+#elif V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
   int cpu_info[4];
 
   // __cpuid with an InfoType argument of 0 returns the number of
   // valid Ids in CPUInfo[0] and the CPU identification string in
   // the other three array elements. The CPU identification string is
   // not in linear order. The code below arranges the information
   // in a human readable form. The human readable order is CPUInfo[1] |
   // CPUInfo[3] | CPUInfo[2]. CPUInfo[2] and CPUInfo[3] are swapped
   // before using memcpy to copy these three array elements to cpu_string.
   __cpuid(cpu_info, 0);
@@ skipping 215 matching lines @@
     if (end == part) {
       part_ = 0;
     }
     delete[] part;
   }
 
 #endif
 }
 
 } }  // namespace v8::base