Megamorphic code cleanup.

runtime/vm/flow_graph_compiler_arm64.cc

 // Copyright (c) 2014, 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"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/compiler.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/deopt_instructions.h"
 #include "vm/il_printer.h"
 #include "vm/instructions.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, trap_on_deoptimization, false, "Trap on deoptimization.");
 DECLARE_FLAG(bool, enable_simd_inline);
-DECLARE_FLAG(bool, use_megamorphic_stub);
 
 
 void MegamorphicSlowPath::EmitNativeCode(FlowGraphCompiler* compiler) {
   Assembler* assembler = compiler->assembler();
 #define __ assembler->
   __ Bind(entry_label());
   __ Comment("MegamorphicSlowPath");
   compiler->EmitMegamorphicInstanceCall(ic_data_, argument_count_, deopt_id_,
                                         token_pos_, locs_, try_index_);
   __ b(exit_label());
@@ skipping 1278 matching lines @@
     __ ldr(R0, FieldAddress(R0, String::hash_offset()));
     __ CompareRegisters(R0, ZR);
     __ b(&done, NE);
     __ mov(R0, R5);  // Restore receiver in R0,
 
     __ Bind(&megamorphic_call);
     __ Comment("Slow case: megamorphic call");
   }
 
   __ LoadObject(R5, cache);
-  if (FLAG_use_megamorphic_stub) {
-    __ ldr(LR, Address(THR, Thread::megamorphic_lookup_entry_point_offset()));
-    __ blr(LR);
-  } else  {
-    StubCode::EmitMegamorphicLookup(assembler());
-  }
+  __ ldr(LR, Address(THR, Thread::megamorphic_lookup_entry_point_offset()));
+  __ blr(LR);
   __ blr(R1);
 
   __ Bind(&done);
   RecordSafepoint(locs, slow_path_argument_count);
   const intptr_t deopt_id_after = Thread::ToDeoptAfter(deopt_id);
   if (FLAG_precompiled_mode) {
     // Megamorphic calls may occur in slow path stubs.
     // If valid use try_index argument.
     if (try_index == CatchClauseNode::kInvalidTryIndex) {
       try_index = CurrentTryIndex();
@@ skipping 594 matching lines @@
 void ParallelMoveResolver::RestoreFpuScratch(FpuRegister reg) {
   __ PopDouble(reg);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64