Reduce size of monomorphic checked entry.

runtime/vm/assembler_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"  // NOLINT
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/heap.h"
@@ skipping 3317 matching lines @@
     int3();
   }
   ASSERT(CodeSize() == Instructions::kCheckedEntryOffset);
 }
 
 
 // RDI receiver, RBX guarded cid as Smi
 void Assembler::MonomorphicCheckedEntry() {
   Label immediate, have_cid, miss;
   Bind(&miss);
-  movq(CODE_REG, Address(THR, Thread::monomorphic_miss_stub_offset()));
-  movq(RCX, FieldAddress(CODE_REG, Code::entry_point_offset()));
-  jmp(RCX);
+  jmp(Address(THR, Thread::monomorphic_miss_entry_offset()));
 
   Bind(&immediate);
   movq(R10, Immediate(kSmiCid));
   jmp(&have_cid, kNearJump);
 
   Comment("MonomorphicCheckedEntry");
   ASSERT(CodeSize() == Instructions::kCheckedEntryOffset);
   SmiUntag(RBX);
   testq(RDI, Immediate(kSmiTagMask));
   j(ZERO, &immediate, kNearJump);
 
   LoadClassId(R10, RDI);
 
   Bind(&have_cid);
   cmpq(R10, RBX);
   j(NOT_EQUAL, &miss, Assembler::kNearJump);
+  nop();

[Florian Schneider, 2016/10/10 21:10:39]

Why is this nop needed?

[rmacnak, 2016/10/11 20:31:04]

IC calls in AOT store the entry as a Smi.

 
   // Fall through to unchecked entry.
   ASSERT(CodeSize() == Instructions::kUncheckedEntryOffset);
   ASSERT((CodeSize() & kSmiTagMask) == kSmiTag);
 }
 
 
 #ifndef PRODUCT
 void Assembler::MaybeTraceAllocation(intptr_t cid,
                                      Label* trace,
@@ skipping 417 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64