Do not count invocations but usage of a function, i.e., increment a function's counter at IC calls …

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2012, 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"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/object_store.h"
@@ skipping 255 matching lines @@
   // Remove the stub frame as we are about to jump to the dart function.
   __ LeaveFrame();
   __ movq(RAX, FieldAddress(RBX, Function::code_offset()));
 
   __ movq(RBX, FieldAddress(RAX, Code::instructions_offset()));
   __ addq(RBX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(RBX);
 }
 
 
-// Called when number of invocations exceeds
-// --optimization_invocation_threshold.
-// RAX: target function.
-// R10: arguments descriptor array (num_args is first Smi element).
-void StubCode::GenerateOptimizeInvokedFunctionStub(Assembler* assembler) {
-  __ Untested("OptimizeInvokedFunction stub");
-  __ EnterFrame(0);
-  __ pushq(R10);  // Preserve arguments descriptor array.
-  __ pushq(RAX);  // Preserve target function.
-  __ pushq(RAX);  // Target function.
-  __ CallRuntimeFromStub(kOptimizeInvokedFunctionRuntimeEntry);
-  __ popq(RAX);  // discard argument.
-  __ popq(RAX);  // Restore function.
-  __ popq(R10);  // Restore arguments descriptor array.
-  __ movq(RAX, FieldAddress(RAX, Function::code_offset()));
-  __ movq(RAX, FieldAddress(RAX, Code::instructions_offset()));
-  __ addq(RAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
-  __ LeaveFrame();
-  __ jmp(RAX);
-  __ int3();
-}
-
-
 // Called from a static call only when an invalid code has been entered
 // (invalid because its function was optimized or deoptimized).
 // RBX: function object.
 // R10: arguments descriptor array (num_args is first Smi element).
 void StubCode::GenerateFixCallersTargetStub(Assembler* assembler) {
   __ Untested("FixCallersTarget stub");
   __ EnterFrame(0);
   __ pushq(R10);  // Preserve arguments descriptor array.
   __ pushq(RBX);  // Preserve target function.
   __ pushq(RBX);  // Target function.
@@ skipping 1230 matching lines @@
 //  R10: Arguments array.
 //  TOS(0): return address
 // Control flow:
 // - If receiver is null -> jump to IC miss.
 // - If receiver is Smi -> load Smi class.
 // - If receiver is not-Smi -> load receiver's class.
 // - Check if 'num_args' (including receiver) match any IC data group.
 // - Match found -> jump to target.
 // - Match not found -> jump to IC miss.
 void StubCode::GenerateNArgsCheckInlineCacheStub(Assembler* assembler,
                                                  intptr_t num_args) {

[regis, 2012/02/24 23:56:25]

How about adding a TODO to check the usage counter and optimize the function as
in the 32-bit version?

[srdjan, 2012/02/25 00:22:10]

Done.

   ASSERT(num_args > 0);
   // Get receiver.
   __ movq(RAX, FieldAddress(R10, Array::data_offset()));
   __ movq(RAX, Address(RSP, RAX, TIMES_4, 0));  // RAX (argument count) is Smi.
 
   Label get_class, ic_miss;
   __ call(&get_class);
   // RAX: receiver's class
   // RBX: IC data array.
 
@@ skipping 167 matching lines @@
   __ popq(R10);
   __ popq(RBX);
   __ LeaveFrame();
   // Now call the dynamic function.
   __ jmp(&StubCode::OneArgCheckInlineCacheLabel());
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64