Revert "Disable bytecode flushing once we toggle coverage mode."

This reverts commit 8aa6b15f.

Reason for revert: broke TSAN https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20stress-incremental-marking/1497/overview

Original change's description:
> Disable bytecode flushing once we toggle coverage mode.
>
> Changing coverage mode generated different bytecode in some cases.
> Hence it is not safe to flush bytecode once we toggle coverage mode.
>
> Bug: chromium:1147917
> Change-Id: I9e640aeaec664d3d4a4aaedf809c568e9ad924fc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2615020
> Commit-Queue: Mythri Alle <mythria@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#71985}

TBR=rmcilroy@chromium.org,mythria@chromium.org

Change-Id: Id4c95da337e291437b7856e2fe7004e1e6405515
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1147917
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2619402Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71989}

src/debug/debug-coverage.cc

@@ -747,10 +747,6 @@ void Coverage::SelectMode(Isolate* isolate, debug::CoverageMode mode) {
     // generated for a function, which can interfere with lazy source positions,
     // so just force source position collection whenever there's such a change.
     isolate->CollectSourcePositionsForAllBytecodeArrays();
-    // Changing the coverage mode changes the generated bytecode and hence it is
-    // not safe to flush bytecode. Set a flag here, so we can disable bytecode
-    // flushing.
-    isolate->set_disable_bytecode_flushing(true);
   }
 
   switch (mode) {

src/execution/isolate.h

@@ -458,7 +458,6 @@ using DebugObjectCache = std::vector<Handle<HeapObject>>;
   /* Current code coverage mode */                                             \
   V(debug::CoverageMode, code_coverage_mode, debug::CoverageMode::kBestEffort) \
   V(debug::TypeProfileMode, type_profile_mode, debug::TypeProfileMode::kNone)  \
-  V(bool, disable_bytecode_flushing, false)                                    \
   V(int, last_console_context_id, 0)                                           \
   V(v8_inspector::V8Inspector*, inspector, nullptr)                            \
   V(bool, next_v8_call_is_safe_for_termination, false)                         \

src/heap/concurrent-marking.cc

@@ -409,7 +409,7 @@ void ConcurrentMarking::Run(JobDelegate* delegate, unsigned mark_compact_epoch,
   MarkingWorklists::Local local_marking_worklists(marking_worklists_);
   ConcurrentMarkingVisitor visitor(
       task_id, &local_marking_worklists, weak_objects_, heap_,
-      mark_compact_epoch, Heap::GetBytecodeFlushMode(heap_->isolate()),
+      mark_compact_epoch, Heap::GetBytecodeFlushMode(),
       heap_->local_embedder_heap_tracer()->InUse(), is_forced_gc,
       &task_state->memory_chunk_data);
   NativeContextInferrer& native_context_inferrer =

src/heap/heap-inl.h

@@ -72,19 +72,6 @@ Address AllocationResult::ToAddress() {
   return HeapObject::cast(object_).address();
 }
 
-// static
-BytecodeFlushMode Heap::GetBytecodeFlushMode(Isolate* isolate) {
-  if (isolate->disable_bytecode_flushing()) {
-    return BytecodeFlushMode::kDoNotFlushBytecode;
-  }
-  if (FLAG_stress_flush_bytecode) {
-    return BytecodeFlushMode::kStressFlushBytecode;
-  } else if (FLAG_flush_bytecode) {
-    return BytecodeFlushMode::kFlushBytecode;
-  }
-  return BytecodeFlushMode::kDoNotFlushBytecode;
-}
-
 Isolate* Heap::isolate() {
   return reinterpret_cast<Isolate*>(
       reinterpret_cast<intptr_t>(this) -

src/heap/heap.h

@@ -445,7 +445,14 @@ class Heap {
 
   // Helper function to get the bytecode flushing mode based on the flags. This
   // is required because it is not safe to acess flags in concurrent marker.
-  static inline BytecodeFlushMode GetBytecodeFlushMode(Isolate* isolate);
+  static inline BytecodeFlushMode GetBytecodeFlushMode() {
+    if (FLAG_stress_flush_bytecode) {
+      return BytecodeFlushMode::kStressFlushBytecode;
+    } else if (FLAG_flush_bytecode) {
+      return BytecodeFlushMode::kFlushBytecode;
+    }
+    return BytecodeFlushMode::kDoNotFlushBytecode;
+  }
 
   static uintptr_t ZapValue() {
     return FLAG_clear_free_memory ? kClearedFreeMemoryValue : kZapValue;

src/heap/mark-compact.cc

@@ -499,7 +499,7 @@ void MarkCompactCollector::StartMarking() {
       std::make_unique<MarkingWorklists::Local>(marking_worklists());
   marking_visitor_ = std::make_unique<MarkingVisitor>(
       marking_state(), local_marking_worklists(), weak_objects(), heap_,
-      epoch(), Heap::GetBytecodeFlushMode(heap()->isolate()),
+      epoch(), Heap::GetBytecodeFlushMode(),
       heap_->local_embedder_heap_tracer()->InUse(),
       heap_->is_current_gc_forced());
 // Marking bits are cleared by the sweeper.