Allows arm cpu feature detection to detect arm64 cpus.

runtime/vm/cpu_arm.cc

 // Copyright (c) 2012, 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_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/cpuinfo.h"
@@ skipping 59 matching lines @@
 const char* HostCPUFeatures::hardware_ = NULL;
 ARMVersion HostCPUFeatures::arm_version_ = ARMvUnknown;
 intptr_t HostCPUFeatures::store_pc_read_offset_ = 8;
 #if defined(DEBUG)
 bool HostCPUFeatures::initialized_ = false;
 #endif
 
 
 #if defined(HOST_ARCH_ARM)
 void HostCPUFeatures::InitOnce() {
+  bool is_arm64 = false;
   CpuInfo::InitOnce();
   hardware_ = CpuInfo::GetCpuModel();
 
-  // Has floating point unit.
-  vfp_supported_ = CpuInfo::FieldContains(kCpuInfoFeatures, "vfp") &&
-                   FLAG_use_vfp;
-
-  // Check for ARMv5TE, ARMv6 or ARMv7. It can be in either the Processor or
-  // Model information fields.
-  if (CpuInfo::FieldContains(kCpuInfoProcessor, "ARM926EJ-S") ||
-      CpuInfo::FieldContains(kCpuInfoModel, "ARM926EJ-S")) {
+  // Check for ARMv5TE, ARMv6, ARMv7, or aarch64.
+  // It can be in either the Processor or Model information fields.
+  if (CpuInfo::FieldContains(kCpuInfoProcessor, "aarch64") ||
+      CpuInfo::FieldContains(kCpuInfoModel, "aarch64")) {
+    // pretend that this arm64 cpu is really an ARMv7
+    arm_version_ = ARMv7;
+    is_arm64 = true;
+  } else if (CpuInfo::FieldContains(kCpuInfoProcessor, "ARM926EJ-S") ||
+             CpuInfo::FieldContains(kCpuInfoModel, "ARM926EJ-S")) {
     // Lego Mindstorm EV3.
     arm_version_ = ARMv5TE;
     // On ARMv5, the PC read offset in an STR or STM instruction is either 8 or
     // 12 bytes depending on the implementation. On the Mindstorm EV3 it is 12
     // bytes.
     store_pc_read_offset_ = 12;
   } else if (CpuInfo::FieldContains(kCpuInfoProcessor, "Feroceon 88FR131") ||
              CpuInfo::FieldContains(kCpuInfoModel, "Feroceon 88FR131")) {
     // This is for the DGBox. For the time-being, assume it is similar to the
     // Lego Mindstorm.
     arm_version_ = ARMv5TE;
     // TODO(zra): Verify with DGLogik that this is correct.
     store_pc_read_offset_ = 12;
   } else if (CpuInfo::FieldContains(kCpuInfoProcessor, "ARMv6") ||
              CpuInfo::FieldContains(kCpuInfoModel, "ARMv6")) {
     // Raspberry Pi, etc.
     arm_version_ = ARMv6;
   } else {
     ASSERT(CpuInfo::FieldContains(kCpuInfoProcessor, "ARMv7") ||
            CpuInfo::FieldContains(kCpuInfoModel, "ARMv7"));
     arm_version_ = ARMv7;
   }
 
+  // Has floating point unit.
+  vfp_supported_ =
+      (CpuInfo::FieldContains(kCpuInfoFeatures, "vfp") || is_arm64) &&
+      FLAG_use_vfp;
+
   // Has integer division.
   bool is_krait = CpuInfo::FieldContains(kCpuInfoHardware, "QCT APQ8064");
   if (is_krait) {
     // Special case for Qualcomm Krait CPUs in Nexus 4 and 7.
     integer_division_supported_ = true;
   } else {
     integer_division_supported_ =
-        CpuInfo::FieldContains(kCpuInfoFeatures, "idiva");
+        CpuInfo::FieldContains(kCpuInfoFeatures, "idiva") || is_arm64;
   }
-  neon_supported_ = CpuInfo::FieldContains(kCpuInfoFeatures, "neon") &&
-                    FLAG_use_vfp && FLAG_use_neon;
+  neon_supported_ =
+      (CpuInfo::FieldContains(kCpuInfoFeatures, "neon") || is_arm64) &&
+      FLAG_use_vfp && FLAG_use_neon;
 
   // Use the cross-compiler's predefined macros to determine whether we should
   // use the hard or soft float ABI.
 #if defined(__ARM_PCS_VFP)
   hardfp_supported_ = true;
 #else
   hardfp_supported_ = false;
 #endif
 
 #if defined(DEBUG)
@@ skipping 45 matching lines @@
   ASSERT(hardware_ != NULL);
   free(const_cast<char*>(hardware_));
   hardware_ = NULL;
   CpuInfo::Cleanup();
 }
 #endif  // defined(HOST_ARCH_ARM)
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM