[turbofan] Making OSR concurrent

... to reduce compilation overhead on the main thread for OSR

Bug: v8:12161
Change-Id: I54ca5fa6201405daf92dac9cf51d5de4b46577b3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3369361Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Fanchen Kong <fanchen.kong@intel.com>
Cr-Commit-Position: refs/heads/main@{#79188}

src/codegen/compiler.cc

@@ -163,11 +163,21 @@ class CompilerTracer : public AllStatic {
     PrintF(scope.file(), "]\n");
   }
 
+  static void TraceStartConcurrentOSRJob(Isolate* isolate,
+                                         Handle<JSFunction> function,
+                                         OptimizedCompilationInfo* info) {
+    if (!FLAG_trace_osr) return;
+    CodeTracer::Scope scope(isolate->GetCodeTracer());
+    PrintTracePrefix(scope, "OSR - Concurrent compiling: ", info);
+    PrintTraceSuffix(scope);
+  }
+
  private:
   static void PrintTracePrefix(const CodeTracer::Scope& scope,
                                const char* header,
                                OptimizedCompilationInfo* info) {
     PrintTracePrefix(scope, header, info->closure(), info->code_kind());
+    PrintF(scope.file(), " osr target offset %d", info->osr_offset().ToInt());
   }
 
   static void PrintTracePrefix(const CodeTracer::Scope& scope,
@@ -990,7 +1000,12 @@ bool GetOptimizedCodeLater(std::unique_ptr<OptimizedCompilationJob> job,
   }
 
   if (CodeKindIsStoredInOptimizedCodeCache(code_kind)) {
-    function->SetOptimizationMarker(OptimizationMarker::kInOptimizationQueue);
+    if (compilation_info->is_osr()) {
+      DCHECK(function->has_feedback_vector());
+      function->shared().set_osr_is_in_optimization_queue(true);
+    } else {
+      function->SetOptimizationMarker(OptimizationMarker::kInOptimizationQueue);
+    }
   }
 
   // Note: Usually the active tier is expected to be Ignition at this point (in
@@ -1026,14 +1041,18 @@ MaybeHandle<CodeT> GetOptimizedCode(
     CodeKind code_kind, BytecodeOffset osr_offset = BytecodeOffset::None(),
     JavaScriptFrame* osr_frame = nullptr,
     GetOptimizedCodeResultHandling result_handling =
-        GetOptimizedCodeResultHandling::kDefault) {
+        GetOptimizedCodeResultHandling::kDefault,
+    int osr_depth = AbstractCode::kNoLoopNestingLevelValue) {
   DCHECK(CodeKindIsOptimizedJSFunction(code_kind));
 
   Handle<SharedFunctionInfo> shared(function->shared(), isolate);
 
   // Make sure we clear the optimization marker on the function so that we
   // don't try to re-optimize.
-  if (function->HasOptimizationMarker()) function->ClearOptimizationMarker();
+  if (function->HasOptimizationMarker() &&
+      osr_offset == BytecodeOffset::None()) {
+    function->ClearOptimizationMarker();
+  }
 
   if (shared->optimization_disabled() &&
       shared->disabled_optimization_reason() == BailoutReason::kNeverOptimize) {
@@ -1057,7 +1076,9 @@ MaybeHandle<CodeT> GetOptimizedCode(
   }
 
   // Check the optimized code cache (stored on the SharedFunctionInfo).
-  if (CodeKindIsStoredInOptimizedCodeCache(code_kind)) {
+  // For OSR, this is handled at GetOptimizedCodeForOSR.
+  if (CodeKindIsStoredInOptimizedCodeCache(code_kind) &&
+      osr_offset == BytecodeOffset::None()) {
     Handle<CodeT> cached_code;
     if (GetCodeFromOptimizedCodeCache(function, osr_offset, code_kind)
             .ToHandle(&cached_code)) {
@@ -1069,7 +1090,9 @@ MaybeHandle<CodeT> GetOptimizedCode(
 
   // Reset profiler ticks, function is no longer considered hot.
   DCHECK(shared->is_compiled());
-  function->feedback_vector().set_profiler_ticks(0);
+  if (osr_offset == BytecodeOffset::None()) {
+    function->feedback_vector().set_profiler_ticks(0);
+  }
 
   VMState<COMPILER> state(isolate);
   TimerEventScope<TimerEventOptimizeCode> optimize_code_timer(isolate);
@@ -1095,6 +1118,16 @@ MaybeHandle<CodeT> GetOptimizedCode(
   if (mode == ConcurrencyMode::kConcurrent) {
     if (GetOptimizedCodeLater(std::move(job), isolate, compilation_info,
                               code_kind, function)) {
+      if (osr_offset != BytecodeOffset::None()) {
+        DCHECK(isolate->concurrent_osr_enabled());
+        compilation_info->set_osr_depth(osr_depth);
+        DCHECK(shared->osr_is_in_optimization_queue());
+        CompilerTracer::TraceStartConcurrentOSRJob(isolate, function,
+                                                   compilation_info);
+        // Return empty handle when execution continues and concurrent
+        // optimization job for OSR has been started (but not finished).
+        return Handle<CodeT>();
+      }
       return ContinuationForConcurrentOptimization(isolate, function);
     }
   } else {
@@ -3204,13 +3237,40 @@ template Handle<SharedFunctionInfo> Compiler::GetSharedFunctionInfo(
     FunctionLiteral* literal, Handle<Script> script, LocalIsolate* isolate);
 
 // static
-MaybeHandle<CodeT> Compiler::GetOptimizedCodeForOSR(
-    Isolate* isolate, Handle<JSFunction> function, BytecodeOffset osr_offset,
-    JavaScriptFrame* osr_frame) {
+MaybeHandle<CodeT> Compiler::GetOptimizedCodeForOSR(Isolate* isolate,
+                                                    Handle<JSFunction> function,
+                                                    BytecodeOffset osr_offset,
+                                                    JavaScriptFrame* osr_frame,
+                                                    int osr_depth) {
   DCHECK(!osr_offset.IsNone());
   DCHECK_NOT_NULL(osr_frame);
-  return GetOptimizedCode(isolate, function, ConcurrencyMode::kNotConcurrent,
-                          CodeKindForOSR(), osr_offset, osr_frame);
+  DCHECK(0 <= osr_depth && osr_depth <= AbstractCode::kMaxLoopNestingMarker);
+
+  CodeKind code_kind = CodeKindForOSR();
+
+  // Check the optimized code cache.
+  if (CodeKindIsStoredInOptimizedCodeCache(code_kind)) {
+    Handle<CodeT> cached_code;
+    if (GetCodeFromOptimizedCodeCache(function, osr_offset, code_kind)
+            .ToHandle(&cached_code)) {
+      CompilerTracer::TraceOptimizedCodeCacheHit(isolate, function, osr_offset,
+                                                 code_kind);
+      return cached_code;
+    }
+  }
+
+  if (isolate->concurrent_osr_enabled() &&
+      function->shared().osr_is_in_optimization_queue()) {
+    return {};
+  }
+
+  return GetOptimizedCode(
+      isolate, function,
+      isolate->concurrent_osr_enabled() && !isolate->bootstrapper()->IsActive()
+          ? ConcurrencyMode::kConcurrent
+          : ConcurrencyMode::kNotConcurrent,
+      code_kind, osr_offset, osr_frame,
+      GetOptimizedCodeResultHandling::kDefault, osr_depth);
 }
 
 // static
@@ -3229,7 +3289,7 @@ bool Compiler::FinalizeOptimizedCompilationJob(OptimizedCompilationJob* job,
   Handle<SharedFunctionInfo> shared = compilation_info->shared_info();
 
   const bool use_result = !compilation_info->discard_result_for_testing();
-  if (V8_LIKELY(use_result)) {
+  if (V8_LIKELY(use_result) && !compilation_info->is_osr()) {
     // Reset profiler ticks, function is no longer considered hot.
     compilation_info->closure()->feedback_vector().set_profiler_ticks(0);
   }
@@ -3252,9 +3312,21 @@ bool Compiler::FinalizeOptimizedCompilationJob(OptimizedCompilationJob* job,
       if (V8_LIKELY(use_result)) {
         InsertCodeIntoOptimizedCodeCache(compilation_info);
         CompilerTracer::TraceCompletedJob(isolate, compilation_info);
-        compilation_info->closure()->set_code(*compilation_info->code(),
-                                              kReleaseStore);
+        if (!compilation_info->is_osr()) {
+          compilation_info->closure()->set_code(*compilation_info->code(),
+                                                kReleaseStore);
+        } else {
+          DCHECK(shared->osr_is_in_optimization_queue());
+          shared->set_osr_is_in_optimization_queue(false);
+          // Store new loop nesting level to trigger OSR and use the optimized
+          // code from OSROptimizedCodeCache during the later execution if
+          // bytecode offsets match.
+          int osr_depth = compilation_info->osr_depth();
+          shared->GetBytecodeArray(isolate).set_osr_loop_nesting_level(
+              std::min({osr_depth + 1, AbstractCode::kMaxLoopNestingMarker}));
+        }
       }
+
       return CompilationJob::SUCCEEDED;
     }
   }
@@ -3268,6 +3340,9 @@ bool Compiler::FinalizeOptimizedCompilationJob(OptimizedCompilationJob* job,
       compilation_info->closure()->ClearOptimizationMarker();
     }
   }
+  if (compilation_info->is_osr() && shared->osr_is_in_optimization_queue()) {
+    shared->set_osr_is_in_optimization_queue(false);
+  }
   return CompilationJob::FAILED;
 }
 

src/codegen/compiler.h

@@ -236,7 +236,7 @@ class V8_EXPORT_PRIVATE Compiler : public AllStatic {
   // Generate and return optimized code for OSR, or empty handle on failure.
   V8_WARN_UNUSED_RESULT static MaybeHandle<CodeT> GetOptimizedCodeForOSR(
       Isolate* isolate, Handle<JSFunction> function, BytecodeOffset osr_offset,
-      JavaScriptFrame* osr_frame);
+      JavaScriptFrame* osr_frame, int osr_depth);
 };
 
 // A base class for compilation jobs intended to run concurrent to the main

src/codegen/optimized-compilation-info.h

@@ -241,6 +241,10 @@ class V8_EXPORT_PRIVATE OptimizedCompilationInfo final {
     return std::move(canonical_handles_);
   }
 
+  void set_osr_depth(int n) { osr_depth_ = n; }
+
+  int osr_depth() const { return osr_depth_; }
+
  private:
   void ConfigureFlags();
 
@@ -312,6 +316,8 @@ class V8_EXPORT_PRIVATE OptimizedCompilationInfo final {
   // handles above. The only difference is that is created in the
   // CanonicalHandleScope(i.e step 1) is different).
   std::unique_ptr<CanonicalHandlesMap> canonical_handles_;
+
+  int osr_depth_ = AbstractCode::kNoLoopNestingLevelValue;
 };
 
 }  // namespace internal

src/compiler-dispatcher/optimizing-compile-dispatcher.cc

@@ -32,6 +32,9 @@ void DisposeCompilationJob(OptimizedCompilationJob* job,
     if (function->IsInOptimizationQueue()) {
       function->ClearOptimizationMarker();
     }
+    if (job->compilation_info()->is_osr()) {
+      function->shared().set_osr_is_in_optimization_queue(false);
+    }
   }
   delete job;
 }
@@ -205,7 +208,7 @@ void OptimizingCompileDispatcher::InstallOptimizedFunctions() {
     }
     OptimizedCompilationInfo* info = job->compilation_info();
     Handle<JSFunction> function(*info->closure(), isolate_);
-    if (function->HasAvailableCodeKind(info->code_kind())) {
+    if (function->HasAvailableCodeKind(info->code_kind()) && !info->is_osr()) {
       if (FLAG_trace_concurrent_recompilation) {
         PrintF("  ** Aborting compilation for ");
         function->ShortPrint();

src/deoptimizer/deoptimizer.cc

@@ -453,6 +453,11 @@ void Deoptimizer::DeoptimizeFunction(JSFunction function, Code code) {
     // this call from here.
     OSROptimizedCodeCache::Compact(
         Handle<NativeContext>(function.context().native_context(), isolate));
+    // Background compilation for OSR arm back edges at compilation finalization
+    // stage regardless of the active execution state (unoptimized/optimized).
+    // Reset osr_loop_nesting_level to avoid unwanted OSR from unoptimized frame
+    // after deoptimization.
+    function.shared().GetBytecodeArray(isolate).set_osr_loop_nesting_level(0);
   }
 }
 

src/execution/isolate.h

@@ -1468,13 +1468,17 @@ class V8_EXPORT_PRIVATE Isolate final : private HiddenFactory {
     return baseline_batch_compiler_;
   }
 
-  bool concurrent_recompilation_enabled() {
+  bool concurrent_recompilation_enabled() const {
     // Thread is only available with flag enabled.
     DCHECK(optimizing_compile_dispatcher_ == nullptr ||
            FLAG_concurrent_recompilation);
     return optimizing_compile_dispatcher_ != nullptr;
   }
 
+  bool concurrent_osr_enabled() const {
+    return concurrent_recompilation_enabled() && FLAG_concurrent_osr;
+  }
+
   OptimizingCompileDispatcher* optimizing_compile_dispatcher() {
     DCHECK_NOT_NULL(optimizing_compile_dispatcher_);
     return optimizing_compile_dispatcher_;

src/execution/tiering-manager.cc

@@ -123,7 +123,6 @@ void TieringManager::MaybeOptimizeFrame(JSFunction function,
                                         CodeKind code_kind) {
   if (function.IsInOptimizationQueue()) {
     TraceInOptimizationQueue(function);
-    return;
   }
 
   if (FLAG_testing_d8_test_runner &&
@@ -155,6 +154,7 @@ void TieringManager::MaybeOptimizeFrame(JSFunction function,
 }
 
 bool TieringManager::MaybeOSR(JSFunction function, UnoptimizedFrame* frame) {
+  if (function.shared().osr_is_in_optimization_queue()) return false;
   int ticks = function.feedback_vector().profiler_ticks();
   if (function.IsMarkedForOptimization() ||
       function.IsMarkedForConcurrentOptimization() ||
@@ -181,9 +181,6 @@ bool ShouldOptimizeAsSmallFunction(int bytecode_size, bool any_ic_changed) {
 OptimizationReason TieringManager::ShouldOptimize(JSFunction function,
                                                   BytecodeArray bytecode,
                                                   JavaScriptFrame* frame) {
-  if (function.ActiveTierIsTurbofan()) {
-    return OptimizationReason::kDoNotOptimize;
-  }
   // If function's SFI has OSR cache, once enter loop range of OSR cache, set
   // OSR loop nesting level for matching condition of OSR (loop_depth <
   // osr_level), soon later OSR will be triggered when executing bytecode
@@ -205,10 +202,18 @@ OptimizationReason TieringManager::ShouldOptimize(JSFunction function,
           current_offset >= jump_target_offset) {
         bytecode.set_osr_loop_nesting_level(iterator.GetImmediateOperand(1) +
                                             1);
-        return OptimizationReason::kHotAndStable;
+        return function.ActiveTierIsTurbofan() ||
+                       function.IsInOptimizationQueue()
+                   ? OptimizationReason::kDoNotOptimize
+                   : OptimizationReason::kHotAndStable;
       }
     }
   }
+
+  if (function.ActiveTierIsTurbofan() || function.HasOptimizationMarker()) {
+    return OptimizationReason::kDoNotOptimize;
+  }
+
   const int ticks = function.feedback_vector().profiler_ticks();
   const int ticks_for_optimization =
       FLAG_ticks_before_optimization +

src/flags/flag-definitions.h

@@ -553,6 +553,7 @@ DEFINE_BOOL(assert_types, false,
             "generate runtime type assertions to test the typer")
 // TODO(tebbi): Support allocating types from background thread.
 DEFINE_NEG_IMPLICATION(assert_types, concurrent_recompilation)
+DEFINE_NEG_IMPLICATION(assert_types, concurrent_osr)
 
 DEFINE_BOOL(trace_compilation_dependencies, false, "trace code dependencies")
 // Depend on --trace-deopt-verbose for reporting dependency invalidations.
@@ -1544,6 +1545,8 @@ DEFINE_BOOL(always_opt, false, "always try to optimize functions")
 DEFINE_IMPLICATION(always_opt, opt)
 DEFINE_BOOL(always_osr, false, "always try to OSR functions")
 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
+DEFINE_BOOL(concurrent_osr, true,
+            "compile turbofan optimized code for osr on background thread")
 
 DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
 #ifdef DEBUG

src/objects/code.h

@@ -814,6 +814,8 @@ class AbstractCode : public HeapObject {
   // nesting that is deeper than 5 levels into account.
   static const int kMaxLoopNestingMarker = 6;
 
+  static const int kNoLoopNestingLevelValue = -1;
+
   OBJECT_CONSTRUCTORS(AbstractCode, HeapObject);
 
  private:

src/objects/shared-function-info-inl.h

@@ -261,6 +261,9 @@ BIT_FIELD_ACCESSORS(SharedFunctionInfo, flags2,
                     has_static_private_methods_or_accessors,
                     SharedFunctionInfo::HasStaticPrivateMethodsOrAccessorsBit)
 
+BIT_FIELD_ACCESSORS(SharedFunctionInfo, flags2, osr_is_in_optimization_queue,
+                    SharedFunctionInfo::OsrIsInOptimizationQueueBit)
+
 BIT_FIELD_ACCESSORS(SharedFunctionInfo, relaxed_flags, syntax_kind,
                     SharedFunctionInfo::FunctionSyntaxKindBits)
 

src/objects/shared-function-info.h

@@ -492,6 +492,8 @@ class SharedFunctionInfo
   // closest outer class scope.
   DECL_BOOLEAN_ACCESSORS(private_name_lookup_skips_outer_class)
 
+  DECL_BOOLEAN_ACCESSORS(osr_is_in_optimization_queue)
+
   inline FunctionKind kind() const;
 
   // Defines the index in a native context of closure's map instantiated using

src/objects/shared-function-info.tq

@@ -44,6 +44,7 @@ bitfield struct SharedFunctionInfoFlags extends uint32 {
 bitfield struct SharedFunctionInfoFlags2 extends uint8 {
   class_scope_has_private_brand: bool: 1 bit;
   has_static_private_methods_or_accessors: bool: 1 bit;
+  osr_is_in_optimization_queue: bool: 1 bit;
 }
 
 @generateBodyDescriptor

src/runtime/runtime-compiler.cc

@@ -19,6 +19,9 @@
 #include "src/execution/v8threads.h"
 #include "src/execution/vm-state-inl.h"
 #include "src/heap/parked-scope.h"
+#include "src/interpreter/bytecode-array-iterator.h"
+#include "src/interpreter/bytecodes.h"
+#include "src/interpreter/interpreter.h"
 #include "src/objects/js-array-buffer-inl.h"
 #include "src/objects/js-array-inl.h"
 #include "src/objects/shared-function-info.h"
@@ -236,7 +239,7 @@ static bool IsSuitableForOnStackReplacement(Isolate* isolate,
 
 namespace {
 
-BytecodeOffset DetermineEntryAndDisarmOSRForUnoptimized(
+std::tuple<BytecodeOffset, int> DetermineEntryAndDisarmOSRForUnoptimized(
     JavaScriptFrame* js_frame) {
   UnoptimizedFrame* frame = reinterpret_cast<UnoptimizedFrame*>(js_frame);
 
@@ -257,9 +260,15 @@ BytecodeOffset DetermineEntryAndDisarmOSRForUnoptimized(
   // Reset the OSR loop nesting depth to disarm back edges.
   bytecode->set_osr_loop_nesting_level(0);
 
+  // Read depth of loop from bytecode array
+  interpreter::BytecodeArrayIterator bytecode_iterator(
+      bytecode, frame->GetBytecodeOffset());
+  int osr_depth = bytecode_iterator.GetImmediateOperand(1);
+
   // Return a BytecodeOffset representing the bytecode offset of the back
-  // branch.
-  return BytecodeOffset(frame->GetBytecodeOffset());
+  // branch and an int which is the loop depth of the corresponding bytecode
+  // offset.
+  return {BytecodeOffset(frame->GetBytecodeOffset()), osr_depth};
 }
 
 }  // namespace
@@ -278,7 +287,10 @@ RUNTIME_FUNCTION(Runtime_CompileForOnStackReplacement) {
 
   // Determine the entry point for which this OSR request has been fired and
   // also disarm all back edges in the calling code to stop new requests.
-  BytecodeOffset osr_offset = DetermineEntryAndDisarmOSRForUnoptimized(frame);
+  BytecodeOffset osr_offset = BytecodeOffset::None();
+  int osr_depth = AbstractCode::kNoLoopNestingLevelValue;
+  std::tie(osr_offset, osr_depth) =
+      DetermineEntryAndDisarmOSRForUnoptimized(frame);
   DCHECK(!osr_offset.IsNone());
 
   MaybeHandle<CodeT> maybe_result;
@@ -290,8 +302,11 @@ RUNTIME_FUNCTION(Runtime_CompileForOnStackReplacement) {
       function->PrintName(scope.file());
       PrintF(scope.file(), " at OSR bytecode offset %d]\n", osr_offset.ToInt());
     }
-    maybe_result =
-        Compiler::GetOptimizedCodeForOSR(isolate, function, osr_offset, frame);
+
+    // With concurrent osr enabled, GetOptimizedCodeForOSR only returns valid
+    // code at OSROptimizeCodeCache hit.
+    maybe_result = Compiler::GetOptimizedCodeForOSR(
+        isolate, function, osr_offset, frame, osr_depth);
   }
 
   // Check whether we ended up with usable optimized code.
@@ -323,15 +338,18 @@ RUNTIME_FUNCTION(Runtime_CompileForOnStackReplacement) {
         // feedback. We cannot do this currently since we OSR only after we mark
         // a function for optimization. We should instead change it to be based
         // based on number of ticks.
-        DCHECK(!function->IsInOptimizationQueue());
-        function->ClearOptimizationMarker();
+        if (function->IsMarkedForOptimization() ||
+            function->IsMarkedForConcurrentOptimization()) {
+          function->ClearOptimizationMarker();
+        }
       }
       // TODO(mythria): Once we have OSR code cache we may not need to mark
       // the function for non-concurrent compilation. We could arm the loops
       // early so the second execution uses the already compiled OSR code and
       // the optimization occurs concurrently off main thread.
       if (!function->HasAvailableOptimizedCode() &&
-          function->feedback_vector().invocation_count() > 1) {
+          function->feedback_vector().invocation_count() > 1 &&
+          !function->IsInOptimizationQueue()) {
         // If we're not already optimized, set to optimize non-concurrently on
         // the next call, otherwise we'd run unoptimized once more and
         // potentially compile for OSR again.
@@ -344,6 +362,7 @@ RUNTIME_FUNCTION(Runtime_CompileForOnStackReplacement) {
         function->SetOptimizationMarker(
             OptimizationMarker::kCompileTurbofan_NotConcurrent);
       }
+      function->feedback_vector().set_profiler_ticks(0);
       return *result;
     }
   }

src/runtime/runtime-test.cc

@@ -264,6 +264,17 @@ bool CanOptimizeFunction(Handle<JSFunction> function, Isolate* isolate,
   return true;
 }
 
+ConcurrencyMode ConcurrencyModeFromString(Handle<Object> mode,
+                                          Isolate* isolate) {
+  if (mode->IsString() &&
+      Handle<String>::cast(mode)->IsOneByteEqualTo(
+          base::StaticCharVector("concurrent")) &&
+      isolate->concurrent_recompilation_enabled()) {
+    return ConcurrencyMode::kConcurrent;
+  }
+  return ConcurrencyMode::kNotConcurrent;
+}
+
 Object OptimizeFunctionOnNextCall(RuntimeArguments& args, Isolate* isolate,
                                   TierupKind tierup_kind) {
   if (args.length() != 1 && args.length() != 2) {
@@ -285,11 +296,7 @@ Object OptimizeFunctionOnNextCall(RuntimeArguments& args, Isolate* isolate,
   if (args.length() == 2) {
     CONVERT_ARG_HANDLE_CHECKED(Object, type, 1);
     if (!type->IsString()) return CrashUnlessFuzzing(isolate);
-    if (Handle<String>::cast(type)->IsOneByteEqualTo(
-            base::StaticCharVector("concurrent")) &&
-        isolate->concurrent_recompilation_enabled()) {
-      concurrency_mode = ConcurrencyMode::kConcurrent;
-    }
+    concurrency_mode = ConcurrencyModeFromString(type, isolate);
   }
   if (FLAG_trace_opt) {
     PrintF("[manually marking ");
@@ -343,6 +350,14 @@ bool EnsureFeedbackVector(Isolate* isolate, Handle<JSFunction> function) {
   return true;
 }
 
+void FinalizeOptimization(Isolate* isolate) {
+  if (isolate->concurrent_recompilation_enabled()) {
+    isolate->optimizing_compile_dispatcher()->AwaitCompileTasks();
+    isolate->optimizing_compile_dispatcher()->InstallOptimizedFunctions();
+    isolate->optimizing_compile_dispatcher()->set_finalize(true);
+  }
+}
+
 }  // namespace
 
 RUNTIME_FUNCTION(Runtime_CompileBaseline) {
@@ -459,13 +474,13 @@ RUNTIME_FUNCTION(Runtime_OptimizeFunctionForTopTier) {
 
 RUNTIME_FUNCTION(Runtime_OptimizeOsr) {
   HandleScope handle_scope(isolate);
-  DCHECK(args.length() == 0 || args.length() == 1);
+  DCHECK(args.length() == 0 || args.length() == 1 || args.length() == 2);
 
   Handle<JSFunction> function;
 
-  // The optional parameter determines the frame being targeted.
+  // The first optional parameter determines the frame being targeted.
   int stack_depth = 0;
-  if (args.length() == 1) {
+  if (args.length() >= 1) {
     if (!args[0].IsSmi()) return CrashUnlessFuzzing(isolate);
     stack_depth = args.smi_at(0);
   }
@@ -476,6 +491,21 @@ RUNTIME_FUNCTION(Runtime_OptimizeOsr) {
   if (!it.done()) function = handle(it.frame()->function(), isolate);
   if (function.is_null()) return CrashUnlessFuzzing(isolate);
 
+  if (it.frame()->is_optimized()) {
+    return ReadOnlyRoots(isolate).undefined_value();
+  }
+
+  if (function->shared().osr_is_in_optimization_queue()) {
+    FinalizeOptimization(isolate);
+    return ReadOnlyRoots(isolate).undefined_value();
+  } else if (function->shared().osr_code_cache_state() !=
+             OSRCodeCacheStateOfSFI::kNotCached) {
+    isolate->tiering_manager()->AttemptOnStackReplacement(
+        UnoptimizedFrame::cast(it.frame()),
+        AbstractCode::kMaxLoopNestingMarker);
+    return ReadOnlyRoots(isolate).undefined_value();
+  }
+
   if (!FLAG_opt) return ReadOnlyRoots(isolate).undefined_value();
 
   if (!function->shared().allows_lazy_compilation()) {
@@ -503,18 +533,33 @@ RUNTIME_FUNCTION(Runtime_OptimizeOsr) {
     return ReadOnlyRoots(isolate).undefined_value();
   }
 
-  // Ensure that the function is marked for non-concurrent optimization, so that
-  // subsequent runs don't also optimize.
+  // The second parameter determines the concurrency mode.
+  ConcurrencyMode concurrency_mode = ConcurrencyMode::kNotConcurrent;
+  if (args.length() == 2) {
+    CONVERT_ARG_HANDLE_CHECKED(Object, type, 1);
+    if (!type->IsString()) return CrashUnlessFuzzing(isolate);
+    concurrency_mode = ConcurrencyModeFromString(type, isolate);
+  }
+
+  if (concurrency_mode == ConcurrencyMode::kNotConcurrent) {
+    CHECK(!isolate->concurrent_osr_enabled());
+  } else {
+    CHECK(isolate->concurrent_osr_enabled());
+  }
+
   if (FLAG_trace_osr) {
     CodeTracer::Scope scope(isolate->GetCodeTracer());
     PrintF(scope.file(), "[OSR - OptimizeOsr marking ");
     function->ShortPrint(scope.file());
-    PrintF(scope.file(), " for non-concurrent optimization]\n");
+    PrintF(scope.file(), " for %s optimization]\n",
+           concurrency_mode == ConcurrencyMode::kConcurrent ? "concurrent"
+                                                            : "non-concurrent");
   }
+
   IsCompiledScope is_compiled_scope(
       function->shared().is_compiled_scope(isolate));
   JSFunction::EnsureFeedbackVector(function, &is_compiled_scope);
-  function->MarkForOptimization(ConcurrencyMode::kNotConcurrent);
+  function->MarkForOptimization(concurrency_mode);
 
   // Make the profiler arm all back edges in unoptimized code.
   if (it.frame()->is_unoptimized()) {
@@ -672,11 +717,7 @@ RUNTIME_FUNCTION(Runtime_WaitForBackgroundOptimization) {
 
 RUNTIME_FUNCTION(Runtime_FinalizeOptimization) {
   DCHECK_EQ(0, args.length());
-  if (isolate->concurrent_recompilation_enabled()) {
-    isolate->optimizing_compile_dispatcher()->AwaitCompileTasks();
-    isolate->optimizing_compile_dispatcher()->InstallOptimizedFunctions();
-    isolate->optimizing_compile_dispatcher()->set_finalize(true);
-  }
+  FinalizeOptimization(isolate);
   return ReadOnlyRoots(isolate).undefined_value();
 }
 

test/cctest/test-api.cc

@@ -28615,7 +28615,7 @@ TEST(FastApiStackSlot) {
       " let foo = 128;"
       " for (let i = 0; i < 100; ++i) {"
       "  let bar = true;"
-      "  if (i == 10) %OptimizeOsr();"
+      "  if (i == 10 || i == 11) %OptimizeOsr(0, \"concurrent\");"
       "  try { receiver.api_func(arg) } catch(_) {};"
       "  try { receiver.api_func(arg) } catch(_) {};"
       " };"

test/cctest/test-cpu-profiler.cc

@@ -2376,7 +2376,7 @@ static const char* pre_profiling_osr_script = R"(
       for (let pass = 0; pass <= optDuration + deoptDuration; pass++) {
         const startTime = Date.now();
         // Let a few passes go by to ensure we have enough feeback info
-        if (pass == 3) %OptimizeOsr();
+        if (pass == 3 || pass == 4) %OptimizeOsr(0, "concurrent");
         // Force deoptimization. %DeoptimizeNow and %DeoptimizeFunction don't
         // doptimize OSRs.
         if (pass == optDuration) whenPass = () => {};

test/cctest/test-js-to-wasm.cc

@@ -271,6 +271,9 @@ class FastJSWasmCallTester {
     i::FLAG_allow_natives_syntax = true;
     i::FLAG_turbo_inline_js_wasm_calls = true;
     i::FLAG_stress_background_compile = false;
+    // Disable concurrent osr to avoid background compilation after test has
+    // been finished.
+    i::FLAG_concurrent_osr = false;
   }
 
   void DeclareCallback(const char* name, FunctionSig* signature,

test/debugger/debug/compiler/osr-typing-debug-change.js

@@ -31,7 +31,7 @@ function ChangeSmiConstantAndOsr() {
   var j = 1;
   for (var i = 0; i < 4; i++) {
     if (i == 2) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       g();
     }
   }
@@ -49,7 +49,7 @@ function ChangeFloatConstantAndOsr() {
   var j = 0.1;
   for (var i = 0; i < 4; i++) {
     if (i == 2) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       g();
     }
   }
@@ -68,7 +68,7 @@ function ChangeFloatVarAndOsr() {
   for (var i = 0; i < 4; i++) {
     j = j + 0.1;
     if (i == 2) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       g();
     }
   }
@@ -102,7 +102,7 @@ function ChangeIntVarAndOsr() {
   for (var i = 0; i < 4; i++) {
     j = j + 1|0;
     if (i == 2) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       g();
     }
   }

test/debugger/debug/regress/regress-5279.js

@@ -11,7 +11,7 @@ function f() {
   const myObj = {};
 
   for (let i = 0; i < 10; i++) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     %ScheduleBreak();
     %PrepareFunctionForOptimization(f);
   }

test/debugger/debug/regress/regress-crbug-387599.js

@@ -8,7 +8,7 @@ Debug.setListener(function() {});
 
 function f() {
   for (var i = 0; i < 100; i++) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(f);
   }
 }

test/debugger/regress/regress-7421.js

@@ -17,7 +17,7 @@ function wrapper1() {
   for (var i = 0; i < 4; i++) {
     // Get this function optimized before calling to increment.
     // Check that that call performs the necessary side-effect checks.
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(wrapper1);
   }
   f1();

test/mjsunit/baseline/test-concurrent-osr.js

+// Copyright 2021 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.
+
+// Flags: --allow-natives-syntax --sparkplug --no-always-sparkplug --use-osr
+// Flags: --opt --no-always-opt --deopt-every-n-times=0
+
+function isExecutingBaseline(func) {
+  let opt_status = %GetOptimizationStatus(func);
+  return (opt_status & V8OptimizationStatus.kTopmostFrameIsBaseline) !== 0;
+}
+
+function f() {
+  for (var i = 0; i <= 20; i++) {
+    if (i == 5) {
+      %BaselineOsr();
+    }
+    if (i > 5) {
+      assertTrue(isBaseline(f));
+      assertTrue(isExecutingBaseline(f));
+    }
+  }
+}
+
+%NeverOptimizeFunction(f);
+f();
+
+var expectedStatus = V8OptimizationStatus.kTopmostFrameIsInterpreted;
+
+function checkTopmostFrame(func) {
+  let opt_status = %GetOptimizationStatus(func);
+  assertTrue ((opt_status & expectedStatus) !== 0, "Expected flag " +
+      expectedStatus + " to be set in optimization status");
+}
+
+function g() {
+  for (var i = 0; i <= 20; i++) {
+    if (i == 6) {
+      let opt_status = %GetOptimizationStatus(g);
+
+      if ((V8OptimizationStatus.kTopmostFrameIsTurboFanned & opt_status) !== 0) {
+        console.log("quit for concurrent osr not enabled.");
+        testRunner.quit(0);
+      }
+    }
+    checkTopmostFrame(g)
+    if (i == 2) {
+      %BaselineOsr();
+      expectedStatus = V8OptimizationStatus.kTopmostFrameIsBaseline;
+    }
+    if (i == 5) {
+      %OptimizeOsr(0, "concurrent");
+    }
+    if (i == 6) {
+      %FinalizeOptimization();
+      expectedStatus = V8OptimizationStatus.kTopmostFrameIsTurboFanned;
+    }
+  }
+}
+
+%PrepareFunctionForOptimization(g);
+g();

test/mjsunit/baseline/test-osr.js

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --sparkplug --no-always-sparkplug --use-osr
-// Flags: --opt --no-always-opt --deopt-every-n-times=0
+// Flags: --opt --no-always-opt --deopt-every-n-times=0 --no-concurrent-osr
 
 function isExecutingBaseline(func) {
   let opt_status = %GetOptimizationStatus(func);

test/mjsunit/compiler/deopt-pretenure.js

@@ -53,7 +53,7 @@ function createSource(name, fillCnt) {
   }
   src +=
   `    if (i == 5) {
-         %OptimizeOsr();
+         %OptimizeOsr(0, "concurrent");
          %PretenureAllocationSite(local_arr);
        }
      }

test/mjsunit/compiler/optimized-for-in.js

@@ -262,7 +262,8 @@ function osr_inner(t, limit) {
     if (t.hasOwnProperty(x)) {
       for (var i = 0; i < t[x].length; i++) {
         r += t[x][i];
-        if (i === limit) %OptimizeOsr();
+        if (i === limit) %OptimizeOsr(0, "concurrent");
+        %FinalizeOptimization();
       }
       r += x;
     }
@@ -278,7 +279,8 @@ function osr_outer(t, osr_after) {
     for (var i = 0; i < t[x].length; i++) {
       r += t[x][i];
     }
-    if (x === osr_after) %OptimizeOsr();
+    if (x === osr_after) %OptimizeOsr(0, "concurrent");
+    %FinalizeOptimization();
     r += x;
   }
   return r;
@@ -289,7 +291,8 @@ function osr_outer_and_deopt(t, osr_after) {
   var r = 1;
   for (var x in t) {
     r += x;
-    if (x == osr_after) %OptimizeOsr();
+    if (x == osr_after) %OptimizeOsr(0, "concurrent");
+    %FinalizeOptimization();
   }
   return r;
 }

test/mjsunit/compiler/osr-alignment.js

@@ -34,7 +34,7 @@ function f1() {
     var y = x + 5;
     var z = y + 3;
     sum += z;
-    if (i == 18) %OptimizeOsr();
+    if (i >= 18) %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }
@@ -46,7 +46,7 @@ function f2() {
     var y = x + 5;
     var z = y + 3;
     sum += z;
-    if (i == 19) %OptimizeOsr();
+    if (i >= 19) %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }
@@ -58,7 +58,7 @@ function f3() {
     var y = x + 5;
     var z = y + 3;
     sum += z;
-    if (i == 20) %OptimizeOsr();
+    if (i >= 20) %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }

test/mjsunit/compiler/osr-arguments.js

@@ -8,7 +8,7 @@ function f1() {
   var sum = 0;
   for (var i = 0; i < 1000; i++) {
     sum += arguments[0] + arguments[1] + arguments[2] + arguments[3];
-    if (i == 18) %OptimizeOsr();
+    if (i == 18 || i == 19) %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }

test/mjsunit/compiler/osr-array-len.js

@@ -9,7 +9,7 @@ function fastaRandom(n, table) {
   var line = new Array(5);
   while (n > 0) {
     if (n < line.length) line = new Array(n);
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     line[0] = n;
     n--;
     %PrepareFunctionForOptimization(fastaRandom);

test/mjsunit/compiler/osr-assert.js

@@ -34,8 +34,8 @@ function f(x, b, c) {
     a = a + 5;
     assertEquals(b + 1, c);
     outer--;
-    if (outer === 5) {
-      %OptimizeOsr();
+    if (outer === 5 || outer === 4) {
+      %OptimizeOsr(0, "concurrent");
     }
   }
   return a + 4;

test/mjsunit/compiler/osr-backedges1.js

@@ -15,7 +15,7 @@ function foo(a) {
     if (i == 5) { i = 6; continue; }
     if (i == 6) { i = 7; continue; }
     if (i == 7) { i = 8; continue; }
-    for (var j = 0; j < 10; j++) { if (i == 5) %OptimizeOsr(); }
+    for (var j = 0; j < 10; j++) { if (i == 5) %OptimizeOsr(0, "concurrent"); }
     break;
   }
   return j;

test/mjsunit/compiler/osr-block-scope-func.js

@@ -11,7 +11,7 @@ function foo() {
   {
     let sum = 0;
     for (var i = 0; i < 100; i++) {
-      if (i == 50) %OptimizeOsr();
+      if (i == 50 || i == 51) %OptimizeOsr(0, "concurrent");
       sum += i;
     }
     result = ret;

test/mjsunit/compiler/osr-block-scope-id.js

@@ -14,7 +14,7 @@ function foo() {
     for (var i = 0; i < 10; i++) {
       {
         let x = i;
-        if (i == 5) %OptimizeOsr();
+        if (i == 5 || i == 6) %OptimizeOsr(0, "concurrent");
         sum += i;
         result.push(function() { return x; });
       }

test/mjsunit/compiler/osr-block-scope.js

@@ -51,7 +51,7 @@ function foo() {
   {
     let sum = 0;
     for (var i = 0; i < 10; i++) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       sum += i;
       %PrepareFunctionForOptimization(foo);
     }
@@ -66,7 +66,7 @@ test(45, foo);
 function bar() {
   let sum = 0;
   for (var i = 0; i < 10; i++) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     sum += i;
     %PrepareFunctionForOptimization(bar);
   }
@@ -80,7 +80,7 @@ function bon() {
   {
     let sum = 0;
     for (var i = 0; i < 10; i++) {
-      if (i == 5) %OptimizeOsr();
+      if (i == 5) %OptimizeOsr(0, "concurrent");
       sum += i;
     }
     return sum;
@@ -96,7 +96,7 @@ function row() {
     let sum = 0;
     while (true) {
       if (i == 8) return sum;
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       sum = i;
       i = i + 1 | 0;
       %PrepareFunctionForOptimization(row);
@@ -111,7 +111,7 @@ test(7, row);
 function nub() {
   let i = 0;
   while (i < 2) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     i++;
     %PrepareFunctionForOptimization(nub);
   }
@@ -126,7 +126,7 @@ function kub() {
   let i = 0;
   while (i < 2) {
     let x = i;
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     i++;
     result = x;
     %PrepareFunctionForOptimization(kub);

test/mjsunit/compiler/osr-for-let.js

@@ -21,7 +21,7 @@ function bar() {
     let sum = 0;
     for (let i = 0; i < 90; i++) {
       sum += i;
-      if (i == 45) %OptimizeOsr();
+      if (i == 45 || i == 46) %OptimizeOsr(0, "concurrent");
     }
     result = sum;
   }
@@ -33,10 +33,10 @@ test(4005, bar);
 
 function baz() {
   let sum = 0;
-  for (let i = 0; i < 2; i++) {
+  for (let i = 0; i < 3; i++) {
     %PrepareFunctionForOptimization(baz);
     sum = 2;
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }
@@ -45,30 +45,30 @@ test(2, baz);
 
 function qux() {
   var result = 0;
-  for (let i = 0; i < 2; i++) {
+  for (let i = 0; i < 3; i++) {
     %PrepareFunctionForOptimization(qux);
     result = i;
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
   }
   return result;
 }
 
-test(1, qux);
+test(2, qux);
 
 function nux() {
   var result = 0;
-  for (let i = 0; i < 2; i++) {
+  for (let i = 0; i < 3; i++) {
     {
       %PrepareFunctionForOptimization(nux);
       let sum = i;
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       result = sum;
     }
   }
   return result;
 }
 
-test(1, nux);
+test(2, nux);
 
 function blo() {
   var result;
@@ -76,7 +76,7 @@ function blo() {
     let sum = 0;
     for (let i = 0; i < 90; i++) {
       sum += i;
-      if (i == 45) %OptimizeOsr();
+      if (i == 45 || i == 46) %OptimizeOsr(0, "concurrent");
     }
     result = ret;
     function ret() {

test/mjsunit/compiler/osr-forin-nested.js

@@ -12,8 +12,8 @@ function test(e, f, v) {
 
 function foo(t) {
   for (var x in t) {
-    for (var i = 0; i < 2; i++) {
-      %OptimizeOsr();
+    for (var i = 0; i < 3; i++) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(foo);
     }
   }
@@ -26,8 +26,8 @@ test(5, foo, {x:20});
 function bar(t) {
   var sum = 0;
   for (var x in t) {
-    for (var i = 0; i < 2; i++) {
-      %OptimizeOsr();
+    for (var i = 0; i < 3; i++) {
+      %OptimizeOsr(0, "concurrent");
       sum += t[x];
       %PrepareFunctionForOptimization(bar);
     }
@@ -36,4 +36,4 @@ function bar(t) {
 }
 %PrepareFunctionForOptimization(bar);
 
-test(62, bar, {x:20,y:11});
+test(93, bar, {x:20,y:11});

test/mjsunit/compiler/osr-infinite.js

@@ -8,7 +8,7 @@ var global_counter = 0;
 
 function thrower() {
   var x = global_counter++;
-  if (x == 5)  %OptimizeOsr(1);
+  if (x == 5 || x == 6)  %OptimizeOsr(1, "concurrent");
   if (x == 10) throw "terminate";
 }
 

test/mjsunit/compiler/osr-labeled.js

@@ -10,7 +10,7 @@ function foo() {
     B: for (var j = 0; j < 5; j++) {
          %PrepareFunctionForOptimization(foo);
       C: for (var k = 0; k < 10; k++) {
-        if (k === 5) %OptimizeOsr();
+        if (k === 4 || k === 5) %OptimizeOsr(0, "concurrent");
         if (k === 6) break B;
         sum++;
       }
@@ -30,7 +30,7 @@ function bar(a) {
          %PrepareFunctionForOptimization(bar);
       C: for (var k = 0; k < 10; k++) {
         sum++;
-        %OptimizeOsr();
+        %OptimizeOsr(0, "concurrent");
         if (a === 1) break A;
         if (a === 2) break B;
         if (a === 3) break C;

test/mjsunit/compiler/osr-literals-adapted.js

@@ -7,7 +7,7 @@
 function mod() {
   function f0() {
     for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f0);
     }
     return {blah: i};
@@ -16,7 +16,7 @@ function mod() {
 
   function f1(a) {
     for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f1);
     }
     return {blah: i};
@@ -25,7 +25,7 @@ function mod() {
 
   function f2(a,b) {
     for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f2);
     }
     return {blah: i};
@@ -34,7 +34,7 @@ function mod() {
 
   function f3(a,b,c) {
     for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f3);
     }
     return {blah: i};
@@ -43,7 +43,7 @@ function mod() {
 
   function f4(a,b,c,d) {
     for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f4);
     }
     return {blah: i};

test/mjsunit/compiler/osr-literals.js

@@ -6,8 +6,8 @@
 
 function mod() {
   function f0() {
-    for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+    for (var i = 0; i < 4; i = i + 1 | 0) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f0);
     }
     return {blah: i};
@@ -15,8 +15,8 @@ function mod() {
   %PrepareFunctionForOptimization(f0);
 
   function f1(a) {
-    for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+    for (var i = 0; i < 4; i = i + 1 | 0) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f1);
     }
     return {blah: i};
@@ -24,8 +24,8 @@ function mod() {
   %PrepareFunctionForOptimization(f1);
 
   function f2(a,b) {
-    for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+    for (var i = 0; i < 4; i = i + 1 | 0) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f2);
     }
     return {blah: i};
@@ -33,8 +33,8 @@ function mod() {
   %PrepareFunctionForOptimization(f2);
 
   function f3(a,b,c) {
-    for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+    for (var i = 0; i < 4; i = i + 1 | 0) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f3);
     }
     return {blah: i};
@@ -42,8 +42,8 @@ function mod() {
   %PrepareFunctionForOptimization(f3);
 
   function f4(a,b,c,d) {
-    for (var i = 0; i < 3; i = i + 1 | 0) {
-      %OptimizeOsr();
+    for (var i = 0; i < 4; i = i + 1 | 0) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(f4);
     }
     return {blah: i};
@@ -51,11 +51,11 @@ function mod() {
   %PrepareFunctionForOptimization(f4);
 
   function bar() {
-    assertEquals(3, f0().blah);
-    assertEquals(3, f1(1).blah);
-    assertEquals(3, f2(1,2).blah);
-    assertEquals(3, f3(1,2,3).blah);
-    assertEquals(3, f4(1,2,3,4).blah);
+    assertEquals(4, f0().blah);
+    assertEquals(4, f1(1).blah);
+    assertEquals(4, f2(1,2).blah);
+    assertEquals(4, f3(1,2,3).blah);
+    assertEquals(4, f4(1,2,3,4).blah);
   }
   bar();
 }

test/mjsunit/compiler/osr-manual1.js

@@ -9,7 +9,7 @@ var counter = 111;
 function gen(w) {  // defeat compiler cache.
  var num = counter++;
   var Z = [ "", "", "", ];
-  Z[w] = "%OptimizeOsr(); %PrepareFunctionForOptimization(f" + num + ")";
+  Z[w] = "%OptimizeOsr(0, \"concurrent\"); %PrepareFunctionForOptimization(f" + num + ")";
   var src =
     "function f" + num + "(a,b,c) {" +
     "  var x = 0;" +

test/mjsunit/compiler/osr-manual2.js

@@ -9,7 +9,7 @@ var counter = 188;
 function gen(w) {  // defeat compiler cache.
  var num = counter++;
   var Z = [ "", "", "", ];
-  Z[w] = "%OptimizeOsr(); %PrepareFunctionForOptimization(f" + num + ")";
+  Z[w] = "%OptimizeOsr(0, \"concurrent\"); %PrepareFunctionForOptimization(f" + num + ")";
   var src =
     "function f" + num + "(a,b,c) {" +
     "  var x = 0;" +

test/mjsunit/compiler/osr-maze1.js

@@ -10,43 +10,43 @@ function bar(goal) {
   var i = 35;
   %PrepareFunctionForOptimization(bar);
   while (i-- > 33) {
-    if (count++ == goal) %OptimizeOsr();
+    if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
     sum = sum + i;
   }
   %PrepareFunctionForOptimization(bar);
   while (i-- > 31) {
-    if (count++ == goal) %OptimizeOsr();
+    if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
     j = 9;
     %PrepareFunctionForOptimization(bar);
     while (j-- > 7) {
-      if (count++ == goal) %OptimizeOsr();
+      if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
       sum = sum + j * 3;
     }
     %PrepareFunctionForOptimization(bar);
     while (j-- > 5) {
-      if (count++ == goal) %OptimizeOsr();
+      if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
       sum = sum + j * 5;
     }
   }
   while (i-- > 29) {
     %PrepareFunctionForOptimization(bar);
-    if (count++ == goal) %OptimizeOsr();
+    if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
     while (j-- > 3) {
       var k = 10;
       %PrepareFunctionForOptimization(bar);
-      if (count++ == goal) %OptimizeOsr();
+      if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
       while (k-- > 8) {
         %PrepareFunctionForOptimization(bar);
-        if (count++ == goal) %OptimizeOsr();
+        if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
         sum = sum + k * 11;
       }
     }
     while (j-- > 1) {
       %PrepareFunctionForOptimization(bar);
-      if (count++ == goal) %OptimizeOsr();
+      if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
       while (k-- > 6) {
         %PrepareFunctionForOptimization(bar);
-        if (count++ == goal) %OptimizeOsr();
+        if (count++ == goal || count == goal + 1) %OptimizeOsr(0, "concurrent");
         sum = sum + j * 13;
       }
     }

test/mjsunit/compiler/osr-maze2.js

@@ -51,7 +51,7 @@ function gen(i) {
   body = body.replace(new RegExp("bar"), "bar" + i);
   for (var j = 1; j < 10; j++) {
     var r = new RegExp("LOOP" + j + "\\(\\);");
-    if (i == j) body = body.replace(r, "%OptimizeOsr(); %PrepareFunctionForOptimization(bar" + i +");");
+    if (i == j || i == j + 1) body = body.replace(r, "%OptimizeOsr(0, \"concurrent\"); %PrepareFunctionForOptimization(bar" + i +");");
     else body = body.replace(r, "");
   }
   return eval("(" + body + ")");

test/mjsunit/compiler/osr-nested.js

@@ -36,7 +36,7 @@ function f() {
       var y = x + 5;
       var z = y + 3;
       sum += z;
-      if (j == 5) %OptimizeOsr();
+      if (j == 5 || j == 6) %OptimizeOsr(0, "concurrent");
     }
   }
   return sum;

test/mjsunit/compiler/osr-nested2.js

@@ -12,7 +12,7 @@ function f() {
       var y = x + 5;
       var z = y + 3;
       sum += z;
-      if (i == 21) %OptimizeOsr();
+      if (i == 21) %OptimizeOsr(0, "concurrent");
     }
   }
   return sum;

test/mjsunit/compiler/osr-nested2b.js

@@ -12,7 +12,7 @@ function f() {
       var y = x + 5;
       var z = y + 3;
       sum += z;
-      if (i == 25) %OptimizeOsr();
+      if (i == 25) %OptimizeOsr(0, "concurrent");
     }
     if (true) break;
   }

test/mjsunit/compiler/osr-nested3.js

@@ -13,7 +13,7 @@ function f() {
         var y = x + 5;
         var z = y + 3;
         sum += z;
-        if (i == 19) %OptimizeOsr();
+        if (i == 19) %OptimizeOsr(0, "concurrent");
       }
     }
   }

test/mjsunit/compiler/osr-nested3b.js

@@ -13,7 +13,7 @@ function f() {
         var y = x + 5;
         var z = y + 3;
         sum += z;
-        if (i == 25) %OptimizeOsr();
+        if (i == 25) %OptimizeOsr(0, "concurrent");
       }
       if (true) break;
     }

test/mjsunit/compiler/osr-one.js

@@ -10,8 +10,8 @@ function f(x) {
   while (count > 0) {
     sum += x;
     count--;
-    if (count == 5) {
-      %OptimizeOsr();
+    if (count == 5 || count == 4) {
+      %OptimizeOsr(0, "concurrent");
     }
   }
   return sum;

test/mjsunit/compiler/osr-regex-id.js

@@ -9,7 +9,7 @@ function id(f) { return f; }
 function foo(a) {
   var r = /\0/;
   for (var i = 0; i < 10; i++) {
-    if (a) %OptimizeOsr();
+    if (a) %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(foo);
   }
   return r;
@@ -18,7 +18,7 @@ function foo(a) {
 
 function bar(a) {
   for (var i = 0; i < 10; i++) {
-    if (a) %OptimizeOsr();
+    if (a) %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(bar);
     var r = /\0/;
   }
@@ -28,7 +28,7 @@ function bar(a) {
 
 function baz(a) {
   for (var i = 0; i < 10; i++) {
-    if (a) %OptimizeOsr();
+    if (a) %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(baz);
   }
   return /\0/;
@@ -38,7 +38,7 @@ function baz(a) {
 function qux(a) {
   for (var i = 0; i < 10; i++) {
     if (i > 5 && a) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(qux);
     } else {
       var r = /\0/;

test/mjsunit/compiler/osr-simple.js

@@ -11,7 +11,7 @@ function f() {
     var y = x + 5;
     var z = y + 3;
     sum += z;
-    if (i == 11) %OptimizeOsr();
+    if (i == 11 || i == 12) %OptimizeOsr(0, "concurrent");
   }
   return sum;
 }

test/mjsunit/compiler/osr-top1.js

@@ -7,7 +7,7 @@
 function f() {
   var sum = 0;
   for (var i = 0; i < 10000; i++) {
-    if (i == 100) %OptimizeOsr();
+    if (i == 100 || i == 101) %OptimizeOsr(0, "concurrent");
     var x = i + 2;
     var y = x + 5;
     var z = y + 3;

test/mjsunit/compiler/osr-top2.js

@@ -8,7 +8,7 @@ function f() {
   for (var j = 0; j < 3; j++) {
     var sum = 0;
     for (var i = 0; i < 1000; i++) {
-      if (i == 100) %OptimizeOsr();
+      if (i == 100 || i == 101) %OptimizeOsr(0, "concurrent");
       var x = i + 2;
       var y = x + 5;
       var z = y + 3;

test/mjsunit/compiler/osr-top3.js

@@ -9,7 +9,7 @@ function f() {
     for (var j = 0; j < 3; j++) {
       var sum = 0;
       for (var i = 0; i < 1000; i++) {
-        if (i == 100) %OptimizeOsr();
+        if (i == 100 || i == 101) %OptimizeOsr(0, "concurrent");
         var x = i + 2;
         var y = x + 5;
         var z = y + 3;

test/mjsunit/compiler/osr-try-catch.js

@@ -14,8 +14,8 @@ function SingleLoop() {
   for (var a = 0; a < 2; a++) {
     try { throw 'The exception should have been caught.'; }
     catch(e) {}
-    for (var b = 0; b < 1; b++) {
-      %OptimizeOsr();
+    for (var b = 0; b < 2; b++) {
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(SingleLoop);
     }
   }
@@ -33,10 +33,10 @@ function EmptyBody() {
   try {; } catch(e) {; }
   var a = 0;
   while (1) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     print("foo");
 
-    if (a == 1) break;
+    if (a == 2) break;
     a++;
     %PrepareFunctionForOptimization(EmptyBody);
   }
@@ -46,12 +46,12 @@ function EmptyBody() {
 function NestedLoops() {
   for (var a = 0; a < 2; a++) {
     try {; } catch(e) {; }
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     var b = 0;
     while (1) {
       print("bar");
 
-      if (b == 1) break;
+      if (b == 2) break;
       b++;
     }
     %PrepareFunctionForOptimization(NestedLoops);

test/mjsunit/compiler/osr-two.js

@@ -12,8 +12,8 @@ function f(x) {
     while (inner > 0) {
       sum += x;
       inner--;
-      if (inner == 5) {
-        %OptimizeOsr();
+      if (inner == 5 || inner == 4) {
+        %OptimizeOsr(0, "concurrent");
       }
     }
     outer--;

test/mjsunit/compiler/osr-while-let.js

@@ -25,7 +25,7 @@ function foo() {
       var flag = 1;
       for (; flag == 1; (flag = 0, temp_x = x)) {
         if (x < 2) {
-          result = x; %OptimizeOsr();
+          result = x; %OptimizeOsr(0, "concurrent");
           %PrepareFunctionForOptimization(foo);
         } else {
           break outer;
@@ -48,7 +48,7 @@ function smo() {
     outer: while (true) {
       let y = x;
       for (var i = 0; i < 5; i++) {
-        %OptimizeOsr();
+        %OptimizeOsr(0, "concurrent");
         %PrepareFunctionForOptimization(smo);
         if (i) break outer;
         else result = y;

test/mjsunit/compiler/regress-607493.js

@@ -11,7 +11,7 @@
     for (var x in a) {
       try {
         for (var i = 0; i < 10; i++) {
-          %OptimizeOsr();
+          %OptimizeOsr(0, "concurrent");
           %PrepareFunctionForOptimization(g);
         }
         return;
@@ -32,7 +32,7 @@
     for (var x in a) {
       if (x) {
         for (var i = 0; i < 10; i++) {
-          %OptimizeOsr();
+          %OptimizeOsr(0, "concurrent");
           %PrepareFunctionForOptimization(g);
         }
       }

test/mjsunit/compiler/regress-645851.js

@@ -9,7 +9,7 @@ function f() {
   while (1) {
     for (var j = 0; j < 200; j -=  j) {
       sum = sum + 1;
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       if (sum == 2) return;
       %PrepareFunctionForOptimization(f);
     }

test/mjsunit/compiler/regress-650215.js

@@ -8,7 +8,7 @@ function f() {
   var x = 0;
   for (var i = 0; i < 10; i++) {
     x = (2 % x) | 0;
-    if (i === 5) %OptimizeOsr();
+    if (i === 5 || i === 6) %OptimizeOsr(0, "concurrent");
   }
   return x;
 }

test/mjsunit/compiler/regress-669517.js

@@ -8,8 +8,8 @@
   "use asm";
   var f = function() {
     for (var i = 0; i < 10; i++) {
-      if (i == 5) {
-        %OptimizeOsr();
+      if (i == 5 || i == 6) {
+        %OptimizeOsr(0, "concurrent");
       }
     }
     with (Object());

test/mjsunit/compiler/regress-673244.js

@@ -8,7 +8,7 @@ function f() {
   var accumulator = false;
   for (var i = 0; i < 4; i++) {
     accumulator = accumulator.hasOwnProperty(3);
-    if (i === 1) %OptimizeOsr();
+    if (i === 1 || i === 2) %OptimizeOsr(0, "concurrent");
   }
 }
 

test/mjsunit/compiler/regress-803022.js

@@ -5,8 +5,8 @@
 // Flags: --allow-natives-syntax
 
 function foo() {
-  for (var a = 0; a < 2; a++) {
-    if (a === 1) %OptimizeOsr();
+  for (var a = 0; a < 3; a++) {
+    if (a === 1 || a === 2) %OptimizeOsr(0, "concurrent");
     while (0 && 1) {
       for (var j = 1; j < 2; j++) { }
     }

test/mjsunit/compiler/regress-919754.js

@@ -7,7 +7,7 @@
 
 function f(get, ...a) {
   for (let i = 0; i < 1000; i++) {
-    if (i === 999) %OptimizeOsr();
+    if (i === 998 || i === 999) %OptimizeOsr(0, "concurrent");
     a.map(f);
   }
   return get();

test/mjsunit/compiler/try-osr.js

@@ -6,7 +6,7 @@
 
 function OSRInsideTry(x) {
   try {
-    for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+    for (var i = 0; i < 10; i++) { if (i > 5) %OptimizeOsr(0, "concurrent"); }
     throw x;
   } catch (e) {
     return e + 1;
@@ -21,7 +21,7 @@ function OSRInsideCatch(x) {
   try {
     throw x;
   } catch (e) {
-    for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+    for (var i = 0; i < 10; i++) { if (i > 5) %OptimizeOsr(0, "concurrent"); }
     return e + 1;
   }
   return x + 2;
@@ -34,7 +34,7 @@ function OSRInsideFinally_Return(x) {
   try {
     throw x;
   } finally {
-    for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+    for (var i = 0; i < 10; i++) { if (i > 5) %OptimizeOsr(0, "concurrent"); }
     return x + 1;
   }
   return x + 2;
@@ -47,7 +47,7 @@ function OSRInsideFinally_ReThrow(x) {
   try {
     throw x;
   } finally {
-    for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+    for (var i = 0; i < 10; i++) { if (i > 5) %OptimizeOsr(0, "concurrent"); }
   }
   return x + 2;
 }

test/mjsunit/fixed-context-shapes-when-recompiling.js

@@ -18,9 +18,9 @@ function TestVarInInnerFunction() {
     a; b; c;
   }
   // Force recompilation.
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -42,9 +42,9 @@ function TestLetInInnerFunction() {
     let a;
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -62,9 +62,9 @@ function TestConstInInnerFunction() {
     const a = 0;
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -81,9 +81,9 @@ function TestInnerFunctionParameter() {
   function inner(a) {
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -100,9 +100,9 @@ function TestInnerFunctionRestParameter() {
   function inner(...a) {
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -119,9 +119,9 @@ function TestInnerFunctionDestructuredParameter_1() {
   function inner([d, a]) {
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -138,9 +138,9 @@ function TestInnerFunctionDestructuredParameter_2() {
   function inner({d, a}) {
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -155,9 +155,9 @@ function TestInnerArrowFunctionParameter() {
   var b = 2;
   var c = 3;
   (a) => { a; b; c; }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -172,9 +172,9 @@ function TestInnerArrowFunctionRestParameter() {
   var b = 2;
   var c = 3;
   (...a) => { a; b; c; }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -189,9 +189,9 @@ function TestInnerArrowFunctionDestructuredParameter_1() {
   var b = 2;
   var c = 3;
   ([d, a]) => { a; b; c; }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -206,9 +206,9 @@ function TestInnerArrowFunctionDestructuredParameter_2() {
   var b = 2;
   var c = 3;
   ({d, a}) => { a; b; c;  }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -225,9 +225,9 @@ function TestInnerInnerFunctionParameter() {
   function inner() {
     function innerinner(a) { a; b; c; }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -244,9 +244,9 @@ function TestInnerInnerFunctionRestParameter() {
   function inner() {
     function innerinner(...a) { a; b; c; }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -263,9 +263,9 @@ function TestInnerInnerFunctionDestructuredParameter_1() {
   function inner() {
     function innerinner({d, a}) { a; b; c; }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -282,9 +282,9 @@ function TestInnerInnerFunctionDestructuredParameter_2() {
   function inner() {
     function innerinner([d, a]) { a; b; c; }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -301,9 +301,9 @@ function TestInnerInnerArrowFunctionParameter() {
   function inner() {
     var f = a => a + b + c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -320,9 +320,9 @@ function TestInnerInnerArrowFunctionRestParameter() {
   function inner() {
     var f = (...a) => a + b + c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -339,9 +339,9 @@ function TestInnerInnerArrowFunctionDestructuredParameter_1() {
   function inner() {
     var f = ([d, a]) => a + b + c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -358,9 +358,9 @@ function TestInnerInnerArrowFunctionDestructuredParameter_2() {
   function inner() {
     var f = ({d, a}) => a + b + c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -378,9 +378,9 @@ function TestInnerFunctionInnerFunction() {
     function a() { }
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -398,9 +398,9 @@ function TestInnerFunctionSloppyBlockFunction() {
     if (true) { function a() { } }
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -421,9 +421,9 @@ function TestInnerFunctionCatchVariable() {
       a; b; c;
     }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -442,9 +442,9 @@ function TestInnerFunctionLoopVariable1() {
       a; b; c;
     }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -463,9 +463,9 @@ function TestInnerFunctionLoopVariable2() {
       a; b; c;
     }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -484,9 +484,9 @@ function TestInnerFunctionLoopVariable3() {
       a; b; c;
     }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -505,9 +505,9 @@ function TestInnerFunctionLoopVariable4() {
       a; b; c;
     }
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -525,9 +525,9 @@ function TestInnerFunctionClass() {
     class a {}
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -545,9 +545,9 @@ function TestInnerFunctionDestructuring1() {
     var [a, a2] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -565,9 +565,9 @@ function TestInnerFunctionDestructuring2() {
     let [a, a2] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -585,9 +585,9 @@ function TestInnerFunctionDestructuring3() {
     const [a, a2] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -605,9 +605,9 @@ function TestInnerFunctionDestructuring4() {
     var [a2, ...a] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -625,9 +625,9 @@ function TestInnerFunctionDestructuring5() {
     let [a2, ...a] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -645,9 +645,9 @@ function TestInnerFunctionDestructuring6() {
     const [a2, ...a] = [1, 2];
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -665,9 +665,9 @@ function TestInnerFunctionDestructuring7() {
     var {a, a2} = {a: 1, a2: 2};
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -685,9 +685,9 @@ function TestInnerFunctionDestructuring8() {
     let {a, a2} = {a: 1, a2: 2};
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -705,9 +705,9 @@ function TestInnerFunctionDestructuring9() {
     const {a, a2} = {a: 1, a2: 2};
     a; b; c;
   }
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     assertEquals(1, a);
     assertEquals(2, b);
@@ -720,9 +720,9 @@ TestInnerFunctionDestructuring9();
 // A cluster of similar tests where the inner function only declares a variable
 // whose name clashes with an outer function variable name, but doesn't use it.
 function TestRegress650969_1_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -734,9 +734,9 @@ function TestRegress650969_1_var() {
 TestRegress650969_1_var();
 
 function TestRegress650969_1_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -748,9 +748,9 @@ function TestRegress650969_1_let() {
 TestRegress650969_1_let();
 
 function TestRegress650969_2_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -762,9 +762,9 @@ function TestRegress650969_2_var() {
 TestRegress650969_2_var();
 
 function TestRegress650969_2_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -776,9 +776,9 @@ function TestRegress650969_2_let() {
 TestRegress650969_2_let();
 
 function TestRegress650969_2_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -790,9 +790,9 @@ function TestRegress650969_2_const() {
 TestRegress650969_2_const();
 
 function TestRegress650969_3_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -804,9 +804,9 @@ function TestRegress650969_3_var() {
 TestRegress650969_3_var();
 
 function TestRegress650969_3_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -818,9 +818,9 @@ function TestRegress650969_3_let() {
 TestRegress650969_3_let();
 
 function TestRegress650969_4_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -832,9 +832,9 @@ function TestRegress650969_4_var() {
 TestRegress650969_4_var();
 
 function TestRegress650969_4_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -846,9 +846,9 @@ function TestRegress650969_4_let() {
 TestRegress650969_4_let();
 
 function TestRegress650969_4_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -860,9 +860,9 @@ function TestRegress650969_4_const() {
 TestRegress650969_4_const();
 
 function TestRegress650969_9_parameter() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner(a) {}
@@ -872,9 +872,9 @@ function TestRegress650969_9_parameter() {
 TestRegress650969_9_parameter();
 
 function TestRegress650969_9_restParameter() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner(...a) {}
@@ -884,9 +884,9 @@ function TestRegress650969_9_restParameter() {
 TestRegress650969_9_restParameter();
 
 function TestRegress650969_9_destructuredParameter_1() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner([d, a]) {}
@@ -896,9 +896,9 @@ function TestRegress650969_9_destructuredParameter_1() {
 TestRegress650969_9_destructuredParameter_1();
 
 function TestRegress650969_9_destructuredParameter_2() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner({d, a}) {}
@@ -908,9 +908,9 @@ function TestRegress650969_9_destructuredParameter_2() {
 TestRegress650969_9_destructuredParameter_2();
 
 function TestRegress650969_10_parameter() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -922,9 +922,9 @@ function TestRegress650969_10_parameter() {
 TestRegress650969_10_parameter();
 
 function TestRegress650969_10_restParameter() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -936,9 +936,9 @@ function TestRegress650969_10_restParameter() {
 TestRegress650969_10_restParameter();
 
 function TestRegress650969_10_destructuredParameter_1() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -950,9 +950,9 @@ function TestRegress650969_10_destructuredParameter_1() {
 TestRegress650969_10_destructuredParameter_1();
 
 function TestRegress650969_10_destructuredParameter_2() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -964,9 +964,9 @@ function TestRegress650969_10_destructuredParameter_2() {
 TestRegress650969_10_destructuredParameter_2();
 
 function TestRegress650969_11_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -979,9 +979,9 @@ TestRegress650969_11_var();
 
 
 function TestRegress650969_11_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -993,9 +993,9 @@ function TestRegress650969_11_let() {
 TestRegress650969_11_let();
 
 function TestRegress650969_11_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1007,9 +1007,9 @@ function TestRegress650969_11_const() {
 TestRegress650969_11_const();
 
 function TestRegress650969_12_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1021,9 +1021,9 @@ function TestRegress650969_12_var() {
 TestRegress650969_12_var();
 
 function TestRegress650969_12_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1035,9 +1035,9 @@ function TestRegress650969_12_let() {
 TestRegress650969_12_let();
 
 function TestRegress650969_12_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1049,9 +1049,9 @@ function TestRegress650969_12_const() {
 TestRegress650969_12_const();
 
 function TestRegress650969_13_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1063,9 +1063,9 @@ function TestRegress650969_13_var() {
 TestRegress650969_13_var();
 
 function TestRegress650969_13_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1077,9 +1077,9 @@ function TestRegress650969_13_let() {
 TestRegress650969_13_let();
 
 function TestRegress650969_13_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1091,9 +1091,9 @@ function TestRegress650969_13_const() {
 TestRegress650969_13_const();
 
 function TestRegress650969_14_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1105,9 +1105,9 @@ function TestRegress650969_14_var() {
 TestRegress650969_14_var();
 
 function TestRegress650969_14_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1119,9 +1119,9 @@ function TestRegress650969_14_let() {
 TestRegress650969_14_let();
 
 function TestRegress650969_14_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1133,9 +1133,9 @@ function TestRegress650969_14_const() {
 TestRegress650969_14_const();
 
 function TestRegress650969_15_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1147,9 +1147,9 @@ function TestRegress650969_15_var() {
 TestRegress650969_15_var();
 
 function TestRegress650969_15_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1161,9 +1161,9 @@ function TestRegress650969_15_let() {
 TestRegress650969_15_let();
 
 function TestRegress650969_15_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1175,9 +1175,9 @@ function TestRegress650969_15_const() {
 TestRegress650969_15_const();
 
 function TestRegress650969_16_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1189,9 +1189,9 @@ function TestRegress650969_16_var() {
 TestRegress650969_16_var();
 
 function TestRegress650969_16_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1203,9 +1203,9 @@ function TestRegress650969_16_let() {
 TestRegress650969_16_let();
 
 function TestRegress650969_16_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1217,9 +1217,9 @@ function TestRegress650969_16_const() {
 TestRegress650969_16_const();
 
 function TestRegress650969_17_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1231,9 +1231,9 @@ function TestRegress650969_17_var() {
 TestRegress650969_17_var();
 
 function TestRegress650969_17_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1245,9 +1245,9 @@ function TestRegress650969_17_let() {
 TestRegress650969_17_let();
 
 function TestRegress650969_17_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1259,9 +1259,9 @@ function TestRegress650969_17_const() {
 TestRegress650969_17_const();
 
 function TestRegress650969_18() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1273,9 +1273,9 @@ function TestRegress650969_18() {
 TestRegress650969_18();
 
 function TestRegress650969_18() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a;
     function inner() {
@@ -1289,9 +1289,9 @@ TestRegress650969_18();
 // Regression tests for an intermediate stage where unresolved references were
 // discarded too aggressively.
 function TestRegress650969_sidetrack_var() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a = 0;
     function inner() {
@@ -1304,9 +1304,9 @@ function TestRegress650969_sidetrack_var() {
 TestRegress650969_sidetrack_var();
 
 function TestRegress650969_sidetrack_let() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a = 0;
     function inner() {
@@ -1319,9 +1319,9 @@ function TestRegress650969_sidetrack_let() {
 TestRegress650969_sidetrack_let();
 
 function TestRegress650969_sidetrack_const() {
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) {
-      %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i >= 1) {
+      %OptimizeOsr(0, "concurrent");
     }
     var a = 0;
     function inner() {

test/mjsunit/ignition/osr-from-bytecode.js

@@ -6,7 +6,7 @@
 
 function f() {
   for (var i = 0; i < 10; i++) {
-    if (i == 5) %OptimizeOsr();
+    if (i == 5 || i == 6) %OptimizeOsr(0, "concurrent");
   }
 }
 %PrepareFunctionForOptimization(f);

test/mjsunit/ignition/osr-from-generator.js

@@ -7,7 +7,7 @@
 (function TestGeneratorOSRSimple() {
   function* gen1() {
     for (var i = 0; i < 3; ++i) {
-      if (i == 1) %OptimizeOsr();
+      if (i >= 1) %OptimizeOsr(0, "concurrent");
     }
     return 23;
   }
@@ -19,7 +19,10 @@
 (function TestGeneratorOSRYieldAfterArming() {
   function* gen2() {
     for (var i = 0; i < 3; ++i) {
-      if (i == 1) %OptimizeOsr();
+      if (i == 1 || i == 2) {
+        %PrepareFunctionForOptimization(gen2);
+        %OptimizeOsr(0, "concurrent");
+      }
       yield i;
     }
     return 23;
@@ -36,7 +39,7 @@
   function* gen3() {
     for (var i = 0; i < 3; ++i) {
       yield i;
-      if (i == 1) %OptimizeOsr();
+      if (i >= 1) %OptimizeOsr(0, "concurrent");
     }
     return 23;
   }
@@ -53,7 +56,7 @@
     for (var i = 0; i < 3; ++i) {
       for (var j = 0; j < 3; ++j) {
         for (var k = 0; k < 10; ++k) {
-          if (k == 5) %OptimizeOsr();
+          if (k == 5 || k == 6) %OptimizeOsr(0, "concurrent");
         }
         %PrepareFunctionForOptimization(gen4);
       }

test/mjsunit/osr-elements-kind.js

@@ -92,7 +92,7 @@ function test_osr_elements_kind() {
   %NeverOptimizeFunction(construct_smis);
   %NeverOptimizeFunction(construct_doubles);
   %NeverOptimizeFunction(convert_mixed);
-  for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+  for (var i = 0; i < 10; i++) { if (i == 5 || i == 6) %OptimizeOsr(0, "concurrent"); }
 
   // This code exists to eliminate the learning influence of AllocationSites
   // on the following tests.

test/mjsunit/regress/binop-in-effect-context-deopt.js

@@ -33,7 +33,7 @@
     var dummy = deopt + 0;
     for (var i = 0; osr && i < 2; i++) {
       %PrepareFunctionForOptimization(f);
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
     }
     return result;
   }

test/mjsunit/regress/call-function-in-effect-context-deopt.js

@@ -33,7 +33,7 @@ function f(deopt, osr) {
   var dummy = deopt + 0;
   for (var i = 0; osr && i < 2; i++) {
     %PrepareFunctionForOptimization(f);
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
   }
   return result;
 }

test/mjsunit/regress/regress-1034322.js

@@ -15,7 +15,7 @@ function v0() {
 function v1() {
   while (!v0()) {
     // Trigger OSR early to get a crashing case asap.
-    if (ticks == 5) %OptimizeOsr();
+    if (ticks >= 5 && ticks < 10) %OptimizeOsr(0, "concurrent");
     // With the bug fixed, there's no easy way to trigger termination. Instead,
     // run until we reach a certain number of ticks. The crash triggers locally
     // at tick 7562, thus running until 20k ticks to be somewhat safe.

test/mjsunit/regress/regress-1118.js

@@ -47,7 +47,7 @@ function g() { try { return o.f(); } finally { }}
 // This function should be optimized via OSR.
 function h() {
   for (var i = 0; i < 10; i++) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(h);
   }
   g();

test/mjsunit/regress/regress-1257.js

@@ -18,8 +18,8 @@ function foo () {
         l = 0;
         break;
       case 0:
-        if (cnt++ == 5) {
-          %OptimizeOsr();
+        if (cnt++ == 5 || cnt == 6) {
+          %OptimizeOsr(0, "concurrent");
           l = 1;
         }
         break;

test/mjsunit/regress/regress-2618.js

@@ -39,7 +39,7 @@ function f() {
   do {
     do {
       for (var i = 0; i < 10; i++) {
-        %OptimizeOsr();
+        %OptimizeOsr(0, "concurrent");
         %PrepareFunctionForOptimization(f);
       }
       // Note: this check can't be wrapped in a function, because
@@ -74,7 +74,7 @@ function g() {
               do {
                 do {
                   for (var i = 0; i < 10; i++) {
-                    %OptimizeOsr();
+                    %OptimizeOsr(0, "concurrent");
                     %PrepareFunctionForOptimization(g);
                   }
                   var opt_status = %GetOptimizationStatus(g);

test/mjsunit/regress/regress-298269.js

@@ -11,7 +11,7 @@ function Cb(a, trigger) {
     // This will fail after OSR if Runtime_StringCharCodeAt is modified
     // to iterates optimized frames and visit safepoint pointers.
     if (g == "C".charCodeAt(0)) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(Cb);
     }
   }
@@ -24,7 +24,7 @@ var s2 = "long string to make cons string 2";
 Cb(s1 + s2);
 %PrepareFunctionForOptimization(Cb);
 Cb(s1);
-var s3 = "string for triggering osr in Cb";
+var s3 = "string for triggering osr in CCb";
 %PrepareFunctionForOptimization(Cb);
 Cb(s3 + s3);
 %PrepareFunctionForOptimization(Cb);

test/mjsunit/regress/regress-3032.js

@@ -28,7 +28,7 @@
 // Flags: --allow-natives-syntax
 
 function f() {
-  for (var i = 0; i < 10; i++) { if (i == 5) %OptimizeOsr(); }
+  for (var i = 0; i < 10; i++) { if (i == 5 || i == 6) %OptimizeOsr(0, "concurrent"); }
   var xl = 4096;
   var z = i % xl;
 }

test/mjsunit/regress/regress-379770.js

@@ -7,7 +7,7 @@
 function foo(obj) {
   var counter = 1;
   for (var i = 0; i < obj.length; i++) {
-    %OptimizeOsr();
+    %OptimizeOsr(0, "concurrent");
     %PrepareFunctionForOptimization(foo);
   }
   counter += obj;

test/mjsunit/regress/regress-5252.js

@@ -7,7 +7,7 @@
 (function TestNonLoopyLoop() {
   function f() {
     do {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       return 23;
     } while(false)
   }
@@ -20,7 +20,7 @@
 (function TestNonLoopyGenerator() {
   function* g() {
     do {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       yield 23;
       yield 42;
     } while(false)

test/mjsunit/regress/regress-5262.js

@@ -10,7 +10,7 @@ function boom(o) { o.g = h }
 function f(osr_and_recurse) {
   if (osr_and_recurse) {
     for (var i = 0; i < 3; ++i) {
-      if (i == 1) %OptimizeOsr();
+      if (i >= 1) %OptimizeOsr(0, "concurrent");
     }
     %PrepareFunctionForOptimization(f);
     %OptimizeFunctionOnNextCall(f);

test/mjsunit/regress/regress-612412.js

@@ -10,7 +10,7 @@ var f = (function() {
   "use asm";
   return function g(c1, c2) {
     for (var x = 0 ; x < 10; ++x) {
-      if (x == 5) %OptimizeOsr();
+      if (x == 5 || x == 6) %OptimizeOsr(0, "concurrent");
       c1();
     }
   }

test/mjsunit/regress/regress-902552.js

@@ -6,8 +6,8 @@
 
 function f() {
   var C = class {};
-  for (var i = 0; i < 4; ++i) {
-    if (i == 2) %OptimizeOsr();
+  for (var i = 0; i < 5; ++i) {
+    if (i >= 2) %OptimizeOsr(0, "concurrent");
     C.prototype.foo = 42;
   }
 }

test/mjsunit/regress/regress-903697.js

@@ -8,7 +8,10 @@ function f() {
   C = class {};
   for (var i = 0; i < 5; ++i) {
     gc();
-    if (i == 2) %OptimizeOsr();
+    if (i == 2 || i == 3) {
+      %OptimizeOsr(0, "concurrent");
+      %PrepareFunctionForOptimization(f);
+    }
     C.prototype.foo = i + 9000000000000000;
   }
 }

test/mjsunit/regress/regress-crbug-1258603.js

@@ -4,4 +4,4 @@
 //
 // Flags: --allow-natives-syntax --fuzzing --no-testing-d8-test-runner
 
-[1,2,3].reduceRight(() => { %OptimizeOsr(1); });
+[1,2,3].reduceRight(() => { %OptimizeOsr(1, "concurrent"); });

test/mjsunit/regress/regress-crbug-150545.js

@@ -47,7 +47,7 @@
   function outer() {
     inner(1,2,3);
     for (var i = 0; i < 3; i++) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
       %PrepareFunctionForOptimization(outer);
     }
   }

test/mjsunit/regress/regress-crbug-217858.js

@@ -12,7 +12,7 @@ function f() {
 function g() {
   for (var i = 0; i < 300; i++) {
     f();
-    if (i == 150) %OptimizeOsr();
+    if (i == 150 || i == 151) %OptimizeOsr(0, "concurrent");
   }
 }
 %PrepareFunctionForOptimization(g);

test/mjsunit/regress/regress-crbug-480807.js

@@ -10,8 +10,8 @@ function foo() {
     for (var a = 1; a > 0; a--) {
       c += 1;
     }
-    for (var b = 1; b > 0; b--) {
-      %OptimizeOsr();
+    for (var b = 2; b > 0; b--) {
+      %OptimizeOsr(0, "concurrent");
     }
   }
   return c;

test/mjsunit/regress/regress-crbug-513507.js

@@ -10,10 +10,10 @@
 function makeFun() {
   function fun(osr_fuse) {
     for (var i = 0; i < 3; ++i) {
-      if (i == osr_fuse) %OptimizeOsr();
+      if (i >= osr_fuse) %OptimizeOsr(0, "concurrent");
     }
     for (var i = 3; i < 6; ++i) {
-      if (i == osr_fuse) %OptimizeOsr();
+      if (i >= osr_fuse) %OptimizeOsr(0, "concurrent");
     }
   }
   %PrepareFunctionForOptimization(fun);

test/mjsunit/regress/regress-crbug-522895.js

@@ -8,7 +8,7 @@ var body =
   "function bar1(  )  {" +
   "  var i = 35;       " +
   "  while (i-- > 31) {" +
-  "    %OptimizeOsr(); " +
+  "    %OptimizeOsr(0, \"concurrent\"); " +
   "    j = 9;          " +
   "    %PrepareFunctionForOptimization(bar1); " +
   "    while (j-- > 7);" +

test/mjsunit/regress/regress-crbug-638551.js

@@ -5,7 +5,7 @@
 // Flags: --allow-natives-syntax --expose-gc --no-lazy
 
 function f() {
-  for (var i = 0; i < 10; i++) if (i == 5) %OptimizeOsr();
+  for (var i = 0; i < 10; i++) if (i == 5 || i == 6) %OptimizeOsr(0, "concurrent");
   function g() {}
   %PrepareFunctionForOptimization(g);
   %OptimizeFunctionOnNextCall(g);

test/mjsunit/regress/regress-crbug-640369.js

@@ -10,7 +10,7 @@ function A() {
 }
 %EnsureFeedbackVectorForFunction(A);
 function foo() {
-  for (var i = 0; i < 1; i = 2) %OptimizeOsr();
+  for (var i = 0; i < 2; i++) %OptimizeOsr(0, "concurrent");
   return new A();
 }
 %PrepareFunctionForOptimization(foo);

test/mjsunit/regress/regress-crbug-645888.js

@@ -7,7 +7,10 @@
 function f() {
   for (var i = 0; i < 3; ++i) {
     if (i == 1) {
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
+    }
+    if (i == 2) {
+      %OptimizeOsr(0, "concurrent");
       break;  // Trigger next loop.
     }
   }

test/mjsunit/regress/regress-crbug-662830.js

@@ -12,7 +12,7 @@ function f() {
 function g() {
   try { f(); } catch(e) { }
   %PrepareFunctionForOptimization(g);
-  for (var i = 0; i < 3; ++i) if (i === 1) %OptimizeOsr();
+  for (var i = 0; i < 3; ++i) %OptimizeOsr(0, "concurrent");
   %_DeoptimizeNow();
 }
 %PrepareFunctionForOptimization(g);

test/mjsunit/regress/regress-crbug-665587.js

@@ -9,7 +9,7 @@ function f() {
   for (var i = 0; i < 4; ++i) {
     var x = a[0];
     (function() { return x });
-    if (i == 1) %OptimizeOsr();
+    if (i == 1 || i == 2) %OptimizeOsr(0, "concurrent");
     gc();
   }
 }

test/mjsunit/regress/regress-crbug-668795.js

@@ -10,8 +10,8 @@ function g() {
 
 function f() {
   var result = "R:";
-  for (var i = 0; i < 3; ++i) {
-    if (i == 1) %OptimizeOsr();
+  for (var i = 0; i < 4; ++i) {
+    if (i == 1 || i == 2) %OptimizeOsr(0, "concurrent");
     result += g([1])[0];
     result += g([2])[0];
   }
@@ -19,4 +19,4 @@ function f() {
 }
 %PrepareFunctionForOptimization(f);
 
-assertEquals("R:121212", f());
+assertEquals("R:12121212", f());

test/mjsunit/regress/regress-crbug-934166.js

@@ -15,7 +15,7 @@
         // elided.
         with(f&&g&&(s()=N)({...g})){}
       } catch {}
-      %OptimizeOsr();
+      %OptimizeOsr(0, "concurrent");
     }
   }
   %EnsureFeedbackVectorForFunction(f);

test/mjsunit/regress/regress-osr-context.js

@@ -12,7 +12,7 @@
     for (let i = 0; i < 5; ++i) {
       a--;  // Make sure {a} is non-immutable, hence context allocated.
       function g() { return i }  // Make sure block has a context.
-      if (i == 2) %OptimizeOsr();
+      if (i == 2 || i == 3) %OptimizeOsr(0, "concurrent");
     }
     return a;
   }

test/mjsunit/regress/regress-sync-optimized-lists.js

@@ -12,8 +12,11 @@ function get_closure() {
   return function add_field(obj, osr) {
     obj.c = 3;
     var x = 0;
-    if (osr) %OptimizeOsr();
     for (var i = 0; i < 10; i++) {
+      if (osr && %IsBeingInterpreted()) {
+        %OptimizeOsr(0, "concurrent");
+        %PrepareFunctionForOptimization(add_field);
+      }
       x = i + 1;
     }
     return x;