[Interpreter] Add dispatch counters for each bytecode.

src/interpreter/interpreter-assembler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/interpreter-assembler.h"
 
+#include <limits>
 #include <ostream>
 
 #include "src/code-factory.h"
 #include "src/frames.h"
 #include "src/interface-descriptors.h"
 #include "src/interpreter/bytecodes.h"
 #include "src/interpreter/interpreter.h"
 #include "src/machine-type.h"
 #include "src/macro-assembler.h"
 #include "src/zone.h"
@@ skipping 19 matching lines @@
       disable_stack_check_across_call_(false),
       stack_pointer_before_call_(nullptr) {
   accumulator_.Bind(
       Parameter(InterpreterDispatchDescriptor::kAccumulatorParameter));
   context_.Bind(Parameter(InterpreterDispatchDescriptor::kContextParameter));
   bytecode_array_.Bind(
       Parameter(InterpreterDispatchDescriptor::kBytecodeArrayParameter));
   if (FLAG_trace_ignition) {
     TraceBytecode(Runtime::kInterpreterTraceBytecodeEntry);
   }
+  if (FLAG_ignition_count_handler_dispatches) {
+    IncrementDispatchCounter();
+  }
 }
 
 InterpreterAssembler::~InterpreterAssembler() {}
 
 Node* InterpreterAssembler::GetAccumulator() { return accumulator_.value(); }
 
 void InterpreterAssembler::SetAccumulator(Node* value) {
   accumulator_.Bind(value);
 }
 
@@ skipping 547 matching lines @@
   Node* profiling_weight =
       Int32Sub(Int32Constant(kHeapObjectTag + BytecodeArray::kHeaderSize),
                BytecodeOffset());
   UpdateInterruptBudget(profiling_weight);
 
   Node* exit_trampoline_code_object =
       HeapConstant(isolate()->builtins()->InterpreterExitTrampoline());
   DispatchToBytecodeHandler(exit_trampoline_code_object);
 }
 
+void InterpreterAssembler::IncrementDispatchCounter() {

[rmcilroy, 2016/04/05 10:00:46]

nit - could you move this to be near TraceBytecode

[Stefano Sanfilippo, 2016/04/05 14:01:46]

Done.

+  Node* counters = ExternalConstant(
+      ExternalReference::interpreter_handlers_dispatch_counters(isolate()));
+  Node* counter_offset =
+      IntPtrConstant(static_cast<int>(bytecode_) * sizeof(uint32_t));
+  Node* old_counter = Load(MachineType::Uint32(), counters, counter_offset);
+
+  CodeStubAssembler::Label counter_ok(this);
+  CodeStubAssembler::Label counter_saturated(this);
+  CodeStubAssembler::Label end(this);
+
+  Node* counter_reached_max = Word32Equal(
+      old_counter, Int32Constant(std::numeric_limits<uint32_t>::max()));
+  Branch(counter_reached_max, &counter_saturated, &counter_ok);
+  Bind(&counter_ok);
+  Node* new_counter = Int32Add(old_counter, Int32Constant(1));
+  StoreNoWriteBarrier(MachineRepresentation::kWord32, counters, counter_offset,
+                      new_counter);
+  Goto(&end);
+  Bind(&counter_saturated);
+  Goto(&end);
+  Bind(&end);
+}
+
 void InterpreterAssembler::StackCheck() {
   CodeStubAssembler::Label end(this);
   CodeStubAssembler::Label ok(this);
   CodeStubAssembler::Label stack_guard(this);
 
   Node* sp = LoadStackPointer();
   Node* stack_limit = Load(
       MachineType::Pointer(),
       ExternalConstant(ExternalReference::address_of_stack_limit(isolate())));
   Node* condition = UintPtrGreaterThanOrEqual(sp, stack_limit);
@@ skipping 44 matching lines @@
     V8_TARGET_ARCH_S390
   return true;
 #else
 #error "Unknown Architecture"
 #endif
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8