Array constructor can be simplified by loading context from JSFunction.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3856 matching lines @@
   ASSERT(ToRegister(instr->constructor()).is(rdi));
   ASSERT(ToRegister(instr->result()).is(rax));
 
   __ Set(rax, instr->arity());
   __ Move(rbx, instr->hydrogen()->property_cell());
   ElementsKind kind = instr->hydrogen()->elements_kind();
   AllocationSiteOverrideMode override_mode =
       (AllocationSite::GetMode(kind) == TRACK_ALLOCATION_SITE)
           ? DISABLE_ALLOCATION_SITES
           : DONT_OVERRIDE;
-  ContextCheckMode context_mode = CONTEXT_CHECK_NOT_REQUIRED;
 
   if (instr->arity() == 0) {
-    ArrayNoArgumentConstructorStub stub(kind, context_mode, override_mode);
+    ArrayNoArgumentConstructorStub stub(kind, override_mode);
     CallCode(stub.GetCode(isolate()), RelocInfo::CONSTRUCT_CALL, instr);
   } else if (instr->arity() == 1) {
     Label done;
     if (IsFastPackedElementsKind(kind)) {
       Label packed_case;
       // We might need a change here
       // look at the first argument
       __ movq(rcx, Operand(rsp, 0));
       __ testq(rcx, rcx);
       __ j(zero, &packed_case, Label::kNear);
 
       ElementsKind holey_kind = GetHoleyElementsKind(kind);
-      ArraySingleArgumentConstructorStub stub(holey_kind, context_mode,
-                                              override_mode);
+      ArraySingleArgumentConstructorStub stub(holey_kind, override_mode);
       CallCode(stub.GetCode(isolate()), RelocInfo::CONSTRUCT_CALL, instr);
       __ jmp(&done, Label::kNear);
       __ bind(&packed_case);
     }
 
-    ArraySingleArgumentConstructorStub stub(kind, context_mode, override_mode);
+    ArraySingleArgumentConstructorStub stub(kind, override_mode);
     CallCode(stub.GetCode(isolate()), RelocInfo::CONSTRUCT_CALL, instr);
     __ bind(&done);
   } else {
-    ArrayNArgumentsConstructorStub stub(kind, context_mode, override_mode);
+    ArrayNArgumentsConstructorStub stub(kind, override_mode);
     CallCode(stub.GetCode(isolate()), RelocInfo::CONSTRUCT_CALL, instr);
   }
 }
 
 
 void LCodeGen::DoCallRuntime(LCallRuntime* instr) {
   ASSERT(ToRegister(instr->context()).is(rsi));
   CallRuntime(instr->function(), instr->arity(), instr, instr->save_doubles());
 }
 
@@ skipping 1716 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64