cppgc: Move interesting checks behind DEBUG

v8_enable_v8_checks has very little coverage outside of V8 itself.
Move pointer verification checks behind DEBUG so that they fire in
regular debug or dcheck_always_on builds.

Change-Id: Ib2803240dd996f4223e403d20e927aff2955afbc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3242006Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77534}

include/cppgc/internal/persistent-node.h

@@ -141,21 +141,17 @@ class V8_EXPORT PersistentRegion final : public PersistentRegionBase {
   PersistentRegion& operator=(const PersistentRegion&) = delete;
 
   V8_INLINE PersistentNode* AllocateNode(void* owner, TraceCallback trace) {
-#if V8_ENABLE_CHECKS
-    CheckIsCreationThread();
-#endif  // V8_ENABLE_CHECKS
+    CPPGC_DCHECK(IsCreationThread());
     return PersistentRegionBase::AllocateNode(owner, trace);
   }
 
   V8_INLINE void FreeNode(PersistentNode* node) {
-#if V8_ENABLE_CHECKS
-    CheckIsCreationThread();
-#endif  // V8_ENABLE_CHECKS
+    CPPGC_DCHECK(IsCreationThread());
     PersistentRegionBase::FreeNode(node);
   }
 
  private:
-  void CheckIsCreationThread();
+  bool IsCreationThread();
 
   int creation_thread_id_;
 };

include/cppgc/internal/pointer-policies.h

@@ -92,19 +92,19 @@ class DisabledCheckingPolicy {
   void CheckPointer(const void*) {}
 };
 
-#if V8_ENABLE_CHECKS
+#ifdef DEBUG
 // Off heap members are not connected to object graph and thus cannot ressurect
 // dead objects.
 using DefaultMemberCheckingPolicy =
     SameThreadEnabledCheckingPolicy<false /* kCheckOffHeapAssignments*/>;
 using DefaultPersistentCheckingPolicy =
     SameThreadEnabledCheckingPolicy<true /* kCheckOffHeapAssignments*/>;
-#else
+#else   // !DEBUG
 using DefaultMemberCheckingPolicy = DisabledCheckingPolicy;
 using DefaultPersistentCheckingPolicy = DisabledCheckingPolicy;
-#endif
+#endif  // !DEBUG
 // For CT(W)P neither marking information (for value), nor objectstart bitmap
-// (for slot) are guaranteed to be present because there's no synchonization
+// (for slot) are guaranteed to be present because there's no synchronization
 // between heaps after marking.
 using DefaultCrossThreadPersistentCheckingPolicy = DisabledCheckingPolicy;
 

src/heap/cppgc/persistent-node.cc

@@ -109,8 +109,8 @@ PersistentRegion::PersistentRegion(const FatalOutOfMemoryHandler& oom_handler)
   USE(creation_thread_id_);
 }
 
-void PersistentRegion::CheckIsCreationThread() {
-  DCHECK_EQ(creation_thread_id_, v8::base::OS::GetCurrentThreadId());
+bool PersistentRegion::IsCreationThread() {
+  return creation_thread_id_ == v8::base::OS::GetCurrentThreadId();
 }
 
 PersistentRegionLock::PersistentRegionLock() {

test/unittests/heap/cppgc/prefinalizer-unittest.cc

@@ -291,7 +291,7 @@ class GCedHolder : public GarbageCollected<GCedHolder> {
 
 }  // namespace
 
-#if V8_ENABLE_CHECKS
+#if DEBUG
 #ifdef CPPGC_VERIFY_HEAP
 
 TEST_F(PrefinalizerDeathTest, PrefinalizerCanRewireGraphWithDeadObjects) {
@@ -328,7 +328,7 @@ TEST_F(PrefinalizerDeathTest, PrefinalizerCantRessurectObjectOnHeap) {
 }
 
 #endif  // CPPGC_VERIFY_HEAP
-#endif  // V8_ENABLE_CHECKS
+#endif  // DEBUG
 
 #ifdef CPPGC_ALLOW_ALLOCATIONS_IN_PREFINALIZERS
 TEST_F(PrefinalizerTest, AllocatingPrefinalizersInMultipleGCCycles) {