Remove --experimental-classes flag and related dead code.

src/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 404 matching lines @@
 #endif
     CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
     __ RecordJSReturn();
     // Do not use the leave instruction here because it is too short to
     // patch with the code required by the debugger.
     __ movp(rsp, rbp);
     __ popq(rbp);
     int no_frame_start = masm_->pc_offset();
 
     int arg_count = info_->scope()->num_parameters() + 1;
-    if (FLAG_experimental_classes &&
-        IsSubclassConstructor(info_->function()->kind())) {
+    if (IsSubclassConstructor(info_->function()->kind())) {
       arg_count++;
     }
     int arguments_bytes = arg_count * kPointerSize;
     __ Ret(arguments_bytes, rcx);
 
     // Add padding that will be overwritten by a debugger breakpoint.  We
     // have just generated at least 7 bytes: "movp rsp, rbp; pop rbp; ret k"
     // (3 + 1 + 3) for x64 and at least 6 (2 + 1 + 3) bytes for x32.
     const int kPadding = Assembler::kJSReturnSequenceLength -
                          kPointerSize == kInt64Size ? 7 : 6;
@@ skipping 2632 matching lines @@
         PreservePositionScope scope(masm()->positions_recorder());
         VisitForStackValue(property->obj());
       }
       if (is_named_call) {
         EmitCallWithLoadIC(expr);
       } else {
         EmitKeyedCallWithLoadIC(expr, property->key());
       }
     }
   } else if (call_type == Call::SUPER_CALL) {
-    if (FLAG_experimental_classes) {
-      EmitSuperConstructorCall(expr);
-    } else {
-      EmitLoadSuperConstructor();
-      __ Push(result_register());
-      SuperReference* super_ref = callee->AsSuperReference();
-      VisitForStackValue(super_ref->this_var());
-      EmitCall(expr, CallICState::METHOD);
-    }
+    EmitSuperConstructorCall(expr);
   } else {
     DCHECK(call_type == Call::OTHER_CALL);
     // Call to an arbitrary expression not handled specially above.
     { PreservePositionScope scope(masm()->positions_recorder());
       VisitForStackValue(callee);
     }
     __ PushRoot(Heap::kUndefinedValueRootIndex);
     // Emit function call.
     EmitCall(expr);
   }
@@ skipping 2277 matching lines @@
   DCHECK_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64