[interpreter] Avoid tier-up when there is an OSR activation.

src/compiler.cc

 // 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/compiler.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "src/asmjs/asm-js.h"
@@ skipping 833 matching lines @@
                                      public OptimizedFunctionVisitor {
  public:
   explicit InterpreterActivationsFinder(SharedFunctionInfo* shared)
       : shared_(shared), has_activations_(false) {}
 
   void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
     Address* activation_pc_address = nullptr;
     JavaScriptFrameIterator it(isolate, top);
     for (; !it.done(); it.Advance()) {
       JavaScriptFrame* frame = it.frame();
-      if (!frame->is_interpreted()) continue;
-      if (frame->function()->shared() == shared_) {
+      if (FLAG_turbo_from_bytecode && FLAG_ignition_osr &&
+          frame->is_optimized() && frame->function()->shared() == shared_) {
+        // If we are able to optimize functions directly from bytecode, then
+        // there might be optimized OSR code active on the stack that is not
+        // reachable through a function. We count this as an activation.
+        has_activations_ = true;
+      }
+      if (frame->is_interpreted() && frame->function()->shared() == shared_) {
         has_activations_ = true;
         activation_pc_address = frame->pc_address();
       }
     }
 
     if (activation_pc_address) {
       activation_pc_addresses_.push_back(activation_pc_address);
     }
   }
 
@@ skipping 1060 matching lines @@
     DCHECK(shared->is_compiled());
     function->set_literals(cached.literals);
   } else if (shared->is_compiled()) {
     // TODO(mvstanton): pass pretenure flag to EnsureLiterals.
     JSFunction::EnsureLiterals(function);
   }
 }
 
 }  // namespace internal
 }  // namespace v8