Reverts refactoring of CPU feature detection for

runtime/vm/assembler_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
-#include "vm/cpu.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
+DEFINE_FLAG(bool, use_sse41, true, "Use SSE 4.1 if available");
 DECLARE_FLAG(bool, inline_alloc);
 
 
+bool CPUFeatures::sse4_1_supported_ = false;
+#ifdef DEBUG
+bool CPUFeatures::initialized_ = false;
+#endif
+
+bool CPUFeatures::sse4_1_supported() {
+  DEBUG_ASSERT(initialized_);
+  return sse4_1_supported_ && FLAG_use_sse41;
+}
+
+
+#define __ assembler.
+
+void CPUFeatures::InitOnce() {
+  Assembler assembler;
+  __ pushq(RBP);
+  __ pushq(RBX);
+  __ movq(RBP, RSP);
+  // Get feature information in ECX:EDX and return it in RAX.
+  // Note that cpuid operates the same in 64-bit and 32-bit mode.
+  __ movq(RAX, Immediate(1));
+  __ cpuid();
+  __ movl(RAX, RCX);  // Zero extended.
+  __ shlq(RAX, Immediate(32));
+  __ movl(RCX, RDX);  // Zero extended.
+  __ orq(RAX, RCX);
+  __ movq(RSP, RBP);
+  __ popq(RBX);
+  __ popq(RBP);
+  __ ret();
+
+  const Code& code =
+      Code::Handle(Code::FinalizeCode("DetectCPUFeatures", &assembler));
+  Instructions& instructions = Instructions::Handle(code.instructions());
+  typedef uint64_t (*DetectCPUFeatures)();
+  uint64_t features =
+      reinterpret_cast<DetectCPUFeatures>(instructions.EntryPoint())();
+  sse4_1_supported_ = (features & kSSE4_1BitMask) != 0;
+#ifdef DEBUG
+  initialized_ = true;
+#endif
+}
+
+#undef __
+
+
 Assembler::Assembler(bool use_far_branches)
     : buffer_(),
       object_pool_(GrowableObjectArray::Handle()),
       patchable_pool_entries_(),
       prologue_offset_(-1),
       comments_() {
   // Far branching mode is only needed and implemented for MIPS and ARM.
   ASSERT(!use_far_branches);
   if (Isolate::Current() != Dart::vm_isolate()) {
     object_pool_ = GrowableObjectArray::New(Heap::kOld);
@@ skipping 3220 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64