Megamorphic code cleanup.

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2013, 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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/compiler.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.");
 DEFINE_FLAG(bool, unbox_mints, true, "Optimize 64-bit integer arithmetic.");
 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_);
   __ jmp(exit_label());
 #undef __
@@ skipping 1302 matching lines @@
     __ CompareClassId(RDI, kOneByteStringCid);
     __ j(NOT_EQUAL, &megamorphic_call, Assembler::kNearJump);
     __ movq(RAX, FieldAddress(RDI, String::hash_offset()));
     __ cmpq(RAX, Immediate(0));
     __ j(NOT_EQUAL, &done, Assembler::kNearJump);
 
     __ Bind(&megamorphic_call);
     __ Comment("Slow case: megamorphic call");
   }
   __ LoadObject(RBX, cache);
-  if (FLAG_use_megamorphic_stub) {
-    __ call(Address(THR, Thread::megamorphic_lookup_entry_point_offset()));
-  } else  {
-    StubCode::EmitMegamorphicLookup(assembler());
-  }
+  __ call(Address(THR, Thread::megamorphic_lookup_entry_point_offset()));
   __ call(RCX);
 
   __ 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 501 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64