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

runtime/vm/stub_code_ia32.cc

 // Copyright (c) 2011, 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_IA32)
 
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/object_store.h"
 #include "vm/pages.h"
 #include "vm/resolver.h"
 #include "vm/scavenger.h"
 #include "vm/stub_code.h"
 
 
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
 DEFINE_FLAG(bool, use_slow_path, false,
     "Set to true for debugging & verifying the slow paths.");
+DECLARE_FLAG(int, optimization_counter_threshold);
 
 // Input parameters:
 //   ESP : points to return address.
 //   ESP + 4 : address of last argument in argument array.
 //   ESP + 4*EDX : address of first argument in argument array.
 //   ESP + 4*EDX + 4 : address of return value.
 //   ECX : address of the runtime function to call.
 //   EDX : number of arguments to the call.
 // Must preserve callee saved registers EDI and EBX.
 static void GenerateCallRuntimeStub(Assembler* assembler) {
@@ skipping 227 matching lines @@
   // Remove the stub frame as we are about to jump to the dart function.
   __ LeaveFrame();
   __ movl(EAX, FieldAddress(ECX, Function::code_offset()));
 
   __ movl(ECX, FieldAddress(EAX, Code::instructions_offset()));
   __ addl(ECX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(ECX);
 }
 
 
-// Called when number of invocations exceeds
-// --optimization_invocation_threshold.
-// EAX: target function.
-// EDX: arguments descriptor array (num_args is first Smi element).
-void StubCode::GenerateOptimizeInvokedFunctionStub(Assembler* assembler) {
-  __ EnterFrame(0);
-  __ pushl(EDX);  // Preserve arguments descriptor array.
-  __ pushl(EAX);  // Preserve target function.
-  __ pushl(EAX);  // Target function.
-  __ CallRuntimeFromStub(kOptimizeInvokedFunctionRuntimeEntry);
-  __ popl(EAX);  // discard argument.
-  __ popl(EAX);  // Restore function.
-  __ popl(EDX);  // Restore arguments descriptor array.
-  __ movl(EAX, FieldAddress(EAX, Function::code_offset()));
-  __ movl(EAX, FieldAddress(EAX, Code::instructions_offset()));
-  __ addl(EAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
-  __ LeaveFrame();
-  __ jmp(EAX);
-  __ int3();
-}
-
-
 // Called from a static call only when an invalid code has been entered
 // (invalid because its function was optimized or deoptimized).
 // ECX: function object.
 // EDX: arguments descriptor array (num_args is first Smi element).
 void StubCode::GenerateFixCallersTargetStub(Assembler* assembler) {
   __ EnterFrame(0);
   __ pushl(EDX);  // Preserve arguments descriptor array.
   __ pushl(ECX);  // Preserve target function.
   __ pushl(ECX);  // Target function.
   __ CallRuntimeFromStub(kFixCallersTargetRuntimeEntry);
@@ skipping 1236 matching lines @@
 //  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) {
+  __ movl(EBX, FieldAddress(ECX, ICData::function_offset()));
+  __ incl(FieldAddress(EBX, Function::usage_counter_offset()));
+  if (CodeGenerator::CanOptimize()) {
+    __ cmpl(FieldAddress(EBX, Function::usage_counter_offset()),
+        Immediate(FLAG_optimization_counter_threshold));
+    Label not_yet_hot;
+    __ j(LESS_EQUAL, &not_yet_hot);
+    __ EnterFrame(0);
+    __ pushl(ECX);  // Preserve inline cache data object.
+    __ pushl(EDX);  // Preserve arguments array.
+    __ pushl(EBX);  // Argument for runtime: function object.
+    __ CallRuntimeFromStub(kOptimizeInvokedFunctionRuntimeEntry);
+    __ popl(EBX);  // Remove argument.
+    __ popl(EDX);  // Restore arguments array.
+    __ popl(ECX);  // Restore inline cache data object.
+    __ LeaveFrame();
+    __ Bind(&not_yet_hot);
+  }
+
   ASSERT(num_args > 0);
   // Get receiver.
   __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
   __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX (argument_count) is Smi.
 
   Label get_class, ic_miss;
   __ call(&get_class);
   // EAX: receiver's class
   // ECX: IC data array.
 
@@ skipping 170 matching lines @@
   __ popl(EDX);
   __ popl(ECX);
   __ LeaveFrame();
   // Now call the dynamic function.
   __ jmp(&StubCode::OneArgCheckInlineCacheLabel());
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32