Add ARMv8 detection in CpuFeatures.

R=rodolph.perfetta@arm.com, ulan@chromium.org

Review URL: https://codereview.chromium.org/678313002

Cr-Commit-Position: refs/heads/master@{#24949}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24949 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm.cc

@@ -109,6 +109,9 @@ void CpuFeatures::ProbeImpl(bool cross_compile) {
 
   if (cpu.architecture() >= 7) {
     if (FLAG_enable_armv7) supported_ |= 1u << ARMv7;
+    if (FLAG_enable_armv8 && cpu.architecture() >= 8) {
+      supported_ |= 1u << ARMv8;
+    }
     if (FLAG_enable_unaligned_accesses) supported_ |= 1u << UNALIGNED_ACCESSES;
     // Use movw/movt for QUALCOMM ARMv7 cores.
     if (FLAG_enable_movw_movt && cpu.implementer() == base::CPU::QUALCOMM) {

src/flag-definitions.h

@@ -114,6 +114,11 @@ struct MaybeBoolFlag {
 #else
 #define ENABLE_ARMV7_DEFAULT false
 #endif
+#if (defined CAN_USE_ARMV8_INSTRUCTIONS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
+#define ENABLE_ARMV8_DEFAULT true
+#else
+#define ENABLE_ARMV8_DEFAULT false
+#endif
 #if (defined CAN_USE_VFP32DREGS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
 #define ENABLE_32DREGS_DEFAULT true
 #else
@@ -402,6 +407,8 @@ DEFINE_BOOL(enable_vfp3, ENABLE_VFP3_DEFAULT,
             "enable use of VFP3 instructions if available")
 DEFINE_BOOL(enable_armv7, ENABLE_ARMV7_DEFAULT,
             "enable use of ARMv7 instructions if available (ARM only)")
+DEFINE_BOOL(enable_armv8, ENABLE_ARMV8_DEFAULT,
+            "enable use of ARMv8 instructions if available (ARM 32-bit only)")
 DEFINE_BOOL(enable_neon, ENABLE_NEON_DEFAULT,
             "enable use of NEON instructions if available (ARM only)")
 DEFINE_BOOL(enable_sudiv, true,

src/globals.h

@@ -616,6 +616,7 @@ enum CpuFeature {
   // ARM
   VFP3,
   ARMv7,
+  ARMv8,
   SUDIV,
   MLS,
   UNALIGNED_ACCESSES,