cppgc: Revert diagnosing CHECKs for Persistent

This CL reverts two diagnosing CLs that introduced same-thread CHECKS,
recovering all introduced performance regressions.

We will try to add less performance-sensitive checks again in a follow
up.

This reverts commit 0c2bbfd5.
This reverts commit 6643c059.

Bug: chromium:1253650, chromium:1243257, chromium:1274201
Change-Id: I96c41c39c4f58b062574fa11c4a2d76ad030bcf7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3315437
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78245}

include/cppgc/internal/persistent-node.h

@@ -141,18 +141,18 @@ class V8_EXPORT PersistentRegion final : public PersistentRegionBase {
   PersistentRegion& operator=(const PersistentRegion&) = delete;
 
   V8_INLINE PersistentNode* AllocateNode(void* owner, TraceCallback trace) {
-    CPPGC_CHECK(IsCreationThread());
+    CPPGC_DCHECK(IsCreationThread());
     return PersistentRegionBase::AllocateNode(owner, trace);
   }
 
   V8_INLINE void FreeNode(PersistentNode* node) {
-    CPPGC_CHECK(IsCreationThread());
+    CPPGC_DCHECK(IsCreationThread());
     PersistentRegionBase::FreeNode(node);
   }
 
+ private:
   bool IsCreationThread();
 
- private:
   int creation_thread_id_;
 };
 

include/cppgc/persistent.h

@@ -189,15 +189,6 @@ class BasicPersistent final : public PersistentBase,
   // heterogeneous assignments between different Member and Persistent handles
   // based on their actual types.
   V8_CLANG_NO_SANITIZE("cfi-unrelated-cast") T* Get() const {
-    // TODO(chromium:1253650): Temporary CHECK to diagnose issues.
-    if (IsValid()) {
-      CPPGC_CHECK(
-          WeaknessPolicy::GetPersistentRegion(GetValue()).IsCreationThread());
-      CPPGC_CHECK(GetNode() != nullptr);
-    } else {
-      CPPGC_CHECK(GetNode() == nullptr);
-    }
-
     // The const_cast below removes the constness from PersistentBase storage.
     // The following static_cast re-adds any constness if specified through the
     // user-visible template parameter T.
@@ -205,14 +196,6 @@ class BasicPersistent final : public PersistentBase,
   }
 
   void Clear() {
-    // TODO(chromium:1253650): Temporary CHECK to diagnose issues.
-    if (IsValid()) {
-      CPPGC_CHECK(
-          WeaknessPolicy::GetPersistentRegion(GetValue()).IsCreationThread());
-      CPPGC_CHECK(GetNode() != nullptr);
-    } else {
-      CPPGC_CHECK(GetNode() == nullptr);
-    }
     // Simplified version of `Assign()` to allow calling without a complete type
     // `T`.
     if (IsValid()) {

src/heap/cppgc/persistent-node.cc

@@ -103,19 +103,6 @@ void PersistentRegionBase::Trace(Visitor* visitor) {
                nodes_.end());
 }
 
-namespace {
-
-thread_local int thread_id = 0;
-
-int GetCurrentThreadId() {
-  if (thread_id == 0) {
-    thread_id = v8::base::OS::GetCurrentThreadId();
-  }
-  return thread_id;
-}
-
-}  // namespace
-
 PersistentRegion::PersistentRegion(const FatalOutOfMemoryHandler& oom_handler)
     : PersistentRegionBase(oom_handler),
       creation_thread_id_(v8::base::OS::GetCurrentThreadId()) {
@@ -123,10 +110,7 @@ PersistentRegion::PersistentRegion(const FatalOutOfMemoryHandler& oom_handler)
 }
 
 bool PersistentRegion::IsCreationThread() {
-  // Short circuit using TLS cache. If that doesn't work (e.g. in TLS teardown)
-  // fall back to the more expensive call in base.
-  return creation_thread_id_ == GetCurrentThreadId() ||
-         creation_thread_id_ == v8::base::OS::GetCurrentThreadId();
+  return creation_thread_id_ == v8::base::OS::GetCurrentThreadId();
 }
 
 PersistentRegionLock::PersistentRegionLock() {