Refactors CPU feature detection.

runtime/vm/cpu_arm.cc

Index: runtime/vm/cpu_arm.cc
===================================================================
--- runtime/vm/cpu_arm.cc	(revision 31402)
+++ runtime/vm/cpu_arm.cc	(working copy)
@@ -6,13 +6,15 @@
 
 #if defined(TARGET_ARCH_ARM)
 
+#include "vm/cpu.h"
+#include "vm/cpuinfo.h"
+#include "vm/simulator.h"
+
 #if defined(HOST_ARCH_ARM)
 #include <sys/syscall.h>  /* NOLINT */
 #include <unistd.h>  /* NOLINT */
 #endif
 
-#include "vm/cpu.h"
-
 namespace dart {
 
 void CPU::FlushICache(uword start, uword size) {
@@ -48,6 +50,71 @@
   "arm";
 }
 
+
+bool CPUFeatures::integer_division_supported_ = false;
+bool CPUFeatures::neon_supported_ = false;
+char CPUFeatures::hardware_[HARDWARE_LEN] = {0};
+#if defined(DEBUG)
+bool CPUFeatures::initialized_ = false;
+#endif
+
+
+bool CPUFeatures::integer_division_supported() {
+  DEBUG_ASSERT(initialized_);
+  return integer_division_supported_;
+}
+
+
+bool CPUFeatures::neon_supported() {
+  DEBUG_ASSERT(initialized_);
+  return neon_supported_;
+}
+
+
+char* CPUFeatures::hardware() {
+  DEBUG_ASSERT(initialized_);
+  return hardware_;
+}
+
+// If we are using the simulator, allow tests to enable/disable support for
+// integer division.
+#if defined(USING_SIMULATOR)
+void CPUFeatures::set_integer_division_supported(bool supported) {
+  integer_division_supported_ = supported;
+}
+
+
+void CPUFeatures::set_neon_supported(bool supported) {
+  neon_supported_ = supported;
+}
+#endif
+
+
+void CPUFeatures::InitOnce() {
+  CpuInfo::Read();
+  CpuInfo::GetCpuModel(hardware_, HARDWARE_LEN);
+#if defined(USING_SIMULATOR)
+  integer_division_supported_ = true;
+  neon_supported_ = true;
+#else
+  ASSERT(CpuInfo::FieldContains("Processor", "ARMv7"));  // Implements ARMv7.
+  // Has floating point unit.
+  ASSERT(CpuInfo::FieldContains("Features", "vfp"));
+  // Has integer division.
+  if (CpuInfo::FieldContains("Hardware", "QCT APQ8064")) {
+    // Special case for Qualcomm Krait CPUs in Nexus 4 and 7.
+    integer_division_supported_ = true;
+  } else {
+    integer_division_supported_ = CpuInfo::FieldContains("Features", "idiva");
+  }
+  neon_supported_ = CpuInfo::FieldContains("Features", "neon");
+#endif  // defined(USING_SIMULATOR)
+#if defined(DEBUG)
+  initialized_ = true;
+#endif
+}
+
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM