[Atomics] code stubs for atomic operations

src/crankshaft/arm/lithium-codegen-arm.cc

Index: src/crankshaft/arm/lithium-codegen-arm.cc
diff --git a/src/crankshaft/arm/lithium-codegen-arm.cc b/src/crankshaft/arm/lithium-codegen-arm.cc
index c3b208989d2529b7c0d1b81b8ba515de6e5e6d39..25ea4157465c3bbdc2124b6f4f27bef43d5c3894 100644
--- a/src/crankshaft/arm/lithium-codegen-arm.cc
+++ b/src/crankshaft/arm/lithium-codegen-arm.cc
@@ -993,6 +993,16 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
       break;
     }
+    case CodeStub::AtomicsLoad: {

[Jarin, 2016/01/28 08:11:12]

I think you should use the HCallWithDescriptor hydrogen instruction, then you
would not have to do this.

[binji, 2016/01/28 16:20:01]

Thanks!

+      // TODO(binji): better way to do this?
+      AtomicsLoadDescriptor descriptor(isolate());
+      DCHECK(descriptor.GetRegisterParameterCount() == 2);
+      __ Pop(descriptor.GetRegisterParameter(1));
+      __ Pop(descriptor.GetRegisterParameter(0));
+      AtomicsLoadStub stub(isolate());
+      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
+      break;
+    }
     default:
       UNREACHABLE();
   }