Optimize AOT's switchable calls for the monomorphic case.

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"
@@ skipping 1321 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);
-  __ call(Address(THR, Thread::megamorphic_lookup_entry_point_offset()));
-  __ call(RCX);
+  __ call(Address(THR, Thread::megamorphic_lookup_checked_entry_offset()));
 
   __ 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 16 matching lines @@
   __ Drop(argument_count, RCX);
 }
 
 
 void FlowGraphCompiler::EmitSwitchableInstanceCall(
     const ICData& ic_data,
     intptr_t argument_count,
     intptr_t deopt_id,
     TokenPosition token_pos,
     LocationSummary* locs) {
+  ASSERT(ic_data.NumArgsTested() == 1);
+  const Code& initial_stub = Code::ZoneHandle(
+      StubCode::ICLookupThroughFunction_entry()->code());
+
   __ Comment("SwitchableCall");
   __ movq(RDI, Address(RSP, (argument_count - 1) * kWordSize));
-  ASSERT(ic_data.NumArgsTested() == 1);
   __ LoadUniqueObject(RBX, ic_data);
-  __ CallPatchable(*StubCode::ICLookupThroughFunction_entry());
+  __ LoadUniqueObject(CODE_REG, initial_stub);
+  __ movq(RCX, FieldAddress(CODE_REG, Code::checked_entry_point_offset()));
   __ call(RCX);
 
   AddCurrentDescriptor(RawPcDescriptors::kOther,
                        Thread::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
   const intptr_t deopt_id_after = Thread::ToDeoptAfter(deopt_id);
   if (is_optimizing()) {
     AddDeoptIndexAtCall(deopt_id_after, token_pos);
   } else {
     // Add deoptimization continuation point after the call and before the
@@ skipping 464 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64