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diff --git a/deps/v8/src/execution/runtime-profiler.cc b/deps/v8/src/execution/runtime-profiler.cc
new file mode 100644
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+++ b/deps/v8/src/execution/runtime-profiler.cc
@@ -0,0 +1,227 @@
+// Copyright 2012 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/execution/runtime-profiler.h"
+
+#include "src/base/platform/platform.h"
+#include "src/codegen/assembler.h"
+#include "src/codegen/compilation-cache.h"
+#include "src/codegen/compiler.h"
+#include "src/execution/execution.h"
+#include "src/execution/frames-inl.h"
+#include "src/handles/global-handles.h"
+#include "src/init/bootstrapper.h"
+#include "src/interpreter/interpreter.h"
+#include "src/tracing/trace-event.h"
+
+namespace v8 {
+namespace internal {
+
+// Number of times a function has to be seen on the stack before it is
+// optimized.
+static const int kProfilerTicksBeforeOptimization = 2;
+
+// The number of ticks required for optimizing a function increases with
+// the size of the bytecode. This is in addition to the
+// kProfilerTicksBeforeOptimization required for any function.
+static const int kBytecodeSizeAllowancePerTick = 1200;
+
+// Maximum size in bytes of generate code for a function to allow OSR.
+static const int kOSRBytecodeSizeAllowanceBase = 180;
+
+static const int kOSRBytecodeSizeAllowancePerTick = 48;
+
+// Maximum size in bytes of generated code for a function to be optimized
+// the very first time it is seen on the stack.
+static const int kMaxBytecodeSizeForEarlyOpt = 90;
+
+#define OPTIMIZATION_REASON_LIST(V)   \
+  V(DoNotOptimize, "do not optimize") \
+  V(HotAndStable, "hot and stable")   \
+  V(SmallFunction, "small function")
+
+enum class OptimizationReason : uint8_t {
+#define OPTIMIZATION_REASON_CONSTANTS(Constant, message) k##Constant,
+  OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_CONSTANTS)
+#undef OPTIMIZATION_REASON_CONSTANTS
+};
+
+char const* OptimizationReasonToString(OptimizationReason reason) {
+  static char const* reasons[] = {
+#define OPTIMIZATION_REASON_TEXTS(Constant, message) message,
+      OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_TEXTS)
+#undef OPTIMIZATION_REASON_TEXTS
+  };
+  size_t const index = static_cast<size_t>(reason);
+  DCHECK_LT(index, arraysize(reasons));
+  return reasons[index];
+}
+
+#undef OPTIMIZATION_REASON_LIST
+
+std::ostream& operator<<(std::ostream& os, OptimizationReason reason) {
+  return os << OptimizationReasonToString(reason);
+}
+
+RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
+    : isolate_(isolate), any_ic_changed_(false) {}
+
+static void TraceRecompile(JSFunction function, const char* reason,
+                           const char* type) {
+  if (FLAG_trace_opt) {
+    PrintF("[marking ");
+    function.ShortPrint();
+    PrintF(" for %s recompilation, reason: %s", type, reason);
+    PrintF("]\n");
+  }
+}
+
+void RuntimeProfiler::Optimize(JSFunction function, OptimizationReason reason) {
+  DCHECK_NE(reason, OptimizationReason::kDoNotOptimize);
+  TraceRecompile(function, OptimizationReasonToString(reason), "optimized");
+  function.MarkForOptimization(ConcurrencyMode::kConcurrent);
+}
+
+void RuntimeProfiler::AttemptOnStackReplacement(InterpretedFrame* frame,
+                                                int loop_nesting_levels) {
+  JSFunction function = frame->function();
+  SharedFunctionInfo shared = function.shared();
+  if (!FLAG_use_osr || !shared.IsUserJavaScript()) {
+    return;
+  }
+
+  // If the code is not optimizable, don't try OSR.
+  if (shared.optimization_disabled()) return;
+
+  // We're using on-stack replacement: Store new loop nesting level in
+  // BytecodeArray header so that certain back edges in any interpreter frame
+  // for this bytecode will trigger on-stack replacement for that frame.
+  if (FLAG_trace_osr) {
+    PrintF("[OSR - arming back edges in ");
+    function.PrintName();
+    PrintF("]\n");
+  }
+
+  DCHECK_EQ(StackFrame::INTERPRETED, frame->type());
+  int level = frame->GetBytecodeArray().osr_loop_nesting_level();
+  frame->GetBytecodeArray().set_osr_loop_nesting_level(
+      Min(level + loop_nesting_levels, AbstractCode::kMaxLoopNestingMarker));
+}
+
+void RuntimeProfiler::MaybeOptimize(JSFunction function,
+                                    InterpretedFrame* frame) {
+  if (function.IsInOptimizationQueue()) {
+    if (FLAG_trace_opt_verbose) {
+      PrintF("[function ");
+      function.PrintName();
+      PrintF(" is already in optimization queue]\n");
+    }
+    return;
+  }
+
+  if (FLAG_always_osr) {
+    AttemptOnStackReplacement(frame, AbstractCode::kMaxLoopNestingMarker);
+    // Fall through and do a normal optimized compile as well.
+  } else if (MaybeOSR(function, frame)) {
+    return;
+  }
+
+  if (function.shared().optimization_disabled()) return;
+
+  OptimizationReason reason =
+      ShouldOptimize(function, function.shared().GetBytecodeArray());
+
+  if (reason != OptimizationReason::kDoNotOptimize) {
+    Optimize(function, reason);
+  }
+}
+
+bool RuntimeProfiler::MaybeOSR(JSFunction function, InterpretedFrame* frame) {
+  int ticks = function.feedback_vector().profiler_ticks();
+  // TODO(rmcilroy): Also ensure we only OSR top-level code if it is smaller
+  // than kMaxToplevelSourceSize.
+
+  if (function.IsMarkedForOptimization() ||
+      function.IsMarkedForConcurrentOptimization() ||
+      function.HasOptimizedCode()) {
+    // Attempt OSR if we are still running interpreted code even though the
+    // the function has long been marked or even already been optimized.
+    int64_t allowance =
+        kOSRBytecodeSizeAllowanceBase +
+        static_cast<int64_t>(ticks) * kOSRBytecodeSizeAllowancePerTick;
+    if (function.shared().GetBytecodeArray().length() <= allowance) {
+      AttemptOnStackReplacement(frame);
+    }
+    return true;
+  }
+  return false;
+}
+
+OptimizationReason RuntimeProfiler::ShouldOptimize(JSFunction function,
+                                                   BytecodeArray bytecode) {
+  int ticks = function.feedback_vector().profiler_ticks();
+  int ticks_for_optimization =
+      kProfilerTicksBeforeOptimization +
+      (bytecode.length() / kBytecodeSizeAllowancePerTick);
+  if (ticks >= ticks_for_optimization) {
+    return OptimizationReason::kHotAndStable;
+  } else if (!any_ic_changed_ &&
+             bytecode.length() < kMaxBytecodeSizeForEarlyOpt) {
+    // If no IC was patched since the last tick and this function is very
+    // small, optimistically optimize it now.
+    return OptimizationReason::kSmallFunction;
+  } else if (FLAG_trace_opt_verbose) {
+    PrintF("[not yet optimizing ");
+    function.PrintName();
+    PrintF(", not enough ticks: %d/%d and ", ticks,
+           kProfilerTicksBeforeOptimization);
+    if (any_ic_changed_) {
+      PrintF("ICs changed]\n");
+    } else {
+      PrintF(" too large for small function optimization: %d/%d]\n",
+             bytecode.length(), kMaxBytecodeSizeForEarlyOpt);
+    }
+  }
+  return OptimizationReason::kDoNotOptimize;
+}
+
+void RuntimeProfiler::MarkCandidatesForOptimization() {
+  HandleScope scope(isolate_);
+
+  if (!isolate_->use_optimizer()) return;
+
+  DisallowHeapAllocation no_gc;
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"),
+               "V8.MarkCandidatesForOptimization");
+
+  // Run through the JavaScript frames and collect them. If we already
+  // have a sample of the function, we mark it for optimizations
+  // (eagerly or lazily).
+  int frame_count = 0;
+  int frame_count_limit = FLAG_frame_count;
+  for (JavaScriptFrameIterator it(isolate_);
+       frame_count++ < frame_count_limit && !it.done(); it.Advance()) {
+    JavaScriptFrame* frame = it.frame();
+    if (!frame->is_interpreted()) continue;
+
+    JSFunction function = frame->function();
+    DCHECK(function.shared().is_compiled());
+    if (!function.shared().IsInterpreted()) continue;
+
+    if (!function.has_feedback_vector()) continue;
+
+    MaybeOptimize(function, InterpretedFrame::cast(frame));
+
+    // TODO(leszeks): Move this increment to before the maybe optimize checks,
+    // and update the tests to assume the increment has already happened.
+    int ticks = function.feedback_vector().profiler_ticks();
+    if (ticks < Smi::kMaxValue) {
+      function.feedback_vector().set_profiler_ticks(ticks + 1);
+    }
+  }
+  any_ic_changed_ = false;
+}
+
+}  // namespace internal
+}  // namespace v8