[heap] Introduce enum of garbage collection reasons.

src/heap/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 330 matching lines @@
 
 enum ArrayStorageAllocationMode {
   DONT_INITIALIZE_ARRAY_ELEMENTS,
   INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
 };
 
 enum class ClearRecordedSlots { kYes, kNo };
 
 enum class ClearBlackArea { kYes, kNo };
 
+enum class GarbageCollectionReason {
+  kUnknown,
+  kAllocationFailure,
+  kAllocationLimit,
+  kContextDisposal,
+  kCountersExtension,
+  kDebugger,
+  kDeserializer,
+  kExternalMemoryPressure,
+  kFinalizeMarkingViaStackGuard,
+  kFinalizeMarkingViaTask,
+  kFullHashtable,
+  kHeapProfiler,
+  kIdleTask,
+  kLastResort,
+  kLowMemoryNotification,
+  kMakeHeapIterable,
+  kMemoryPressure,
+  kMemoryReducer,
+  kRuntime,
+  kSamplingProfiler,
+  kSnapshotCreator,
+  kTesting
+};
+
 // A queue of objects promoted during scavenge. Each object is accompanied by
 // its size to avoid dereferencing a map pointer for scanning. The last page in
 // to-space is used for the promotion queue. On conflict during scavenge, the
 // promotion queue is allocated externally and all entries are copied to the
 // external queue.
 class PromotionQueue {
  public:
   explicit PromotionQueue(Heap* heap)
       : front_(nullptr),
         rear_(nullptr),
@@ skipping 711 matching lines @@
   void DisableInlineAllocation();
 
   // ===========================================================================
   // Methods triggering GCs. ===================================================
   // ===========================================================================
 
   // Performs garbage collection operation.
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   inline bool CollectGarbage(
-      AllocationSpace space, const char* gc_reason = NULL,
+      AllocationSpace space, GarbageCollectionReason gc_reason,
       const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
 
   // Performs a full garbage collection.  If (flags & kMakeHeapIterableMask) is
   // non-zero, then the slower precise sweeper is used, which leaves the heap
   // in a state where we can iterate over the heap visiting all objects.
   void CollectAllGarbage(
-      int flags = kFinalizeIncrementalMarkingMask, const char* gc_reason = NULL,
+      int flags, GarbageCollectionReason gc_reason,
       const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
 
   // Last hope GC, should try to squeeze as much as possible.
-  void CollectAllAvailableGarbage(const char* gc_reason = NULL);
+  void CollectAllAvailableGarbage(GarbageCollectionReason gc_reason);
 
   // Reports and external memory pressure event, either performs a major GC or
   // completes incremental marking in order to free external resources.
-  void ReportExternalMemoryPressure(const char* gc_reason = NULL);
+  void ReportExternalMemoryPressure();
 
   // Invoked when GC was requested via the stack guard.
   void HandleGCRequest();
 
   // ===========================================================================
   // Iterators. ================================================================
   // ===========================================================================
 
   // Iterates over all roots in the heap.
   void IterateRoots(ObjectVisitor* v, VisitMode mode);
@@ skipping 30 matching lines @@
 
   void ClearRecordedSlot(HeapObject* object, Object** slot);
   void ClearRecordedSlotRange(Address start, Address end);
 
   // ===========================================================================
   // Incremental marking API. ==================================================
   // ===========================================================================
 
   // Start incremental marking and ensure that idle time handler can perform
   // incremental steps.
-  void StartIdleIncrementalMarking();
+  void StartIdleIncrementalMarking(GarbageCollectionReason gc_reason);
 
   // Starts incremental marking assuming incremental marking is currently
   // stopped.
-  void StartIncrementalMarking(int gc_flags = kNoGCFlags,
-                               const GCCallbackFlags gc_callback_flags =
-                                   GCCallbackFlags::kNoGCCallbackFlags,
-                               const char* reason = nullptr);
+  void StartIncrementalMarking(
+      int gc_flags, GarbageCollectionReason gc_reason,
+      GCCallbackFlags gc_callback_flags = GCCallbackFlags::kNoGCCallbackFlags);
 
-  void StartIncrementalMarkingIfNeeded(int gc_flags = kNoGCFlags,
-                                       const GCCallbackFlags gc_callback_flags =
-                                           GCCallbackFlags::kNoGCCallbackFlags,
-                                       const char* reason = nullptr);
+  void StartIncrementalMarkingIfAllocationLimitIsReached(
+      int gc_flags,
+      GCCallbackFlags gc_callback_flags = GCCallbackFlags::kNoGCCallbackFlags);
 
-  void FinalizeIncrementalMarkingIfComplete(const char* comment);
+  void FinalizeIncrementalMarkingIfComplete(GarbageCollectionReason gc_reason);
 
-  bool TryFinalizeIdleIncrementalMarking(double idle_time_in_ms);
+  bool TryFinalizeIdleIncrementalMarking(double idle_time_in_ms,
+                                         GarbageCollectionReason gc_reason);
 
   void RegisterReservationsForBlackAllocation(Reservation* reservations);
 
   IncrementalMarking* incremental_marking() { return incremental_marking_; }
 
   // ===========================================================================
   // Embedder heap tracer support. =============================================
   // ===========================================================================
 
   void SetEmbedderHeapTracer(EmbedderHeapTracer* tracer);
@@ skipping 276 matching lines @@
   void TracePathToGlobal();
 
   void Print();
   void PrintHandles();
 
   // Report heap statistics.
   void ReportHeapStatistics(const char* title);
   void ReportCodeStatistics(const char* title);
 #endif
 
+  static const char* GarbageCollectionReasonToString(
+      GarbageCollectionReason gc_reason);
+
  private:
   class PretenuringScope;
 
   // External strings table is a place where all external strings are
   // registered.  We need to keep track of such strings to properly
   // finalize them.
   class ExternalStringTable {
    public:
     // Registers an external string.
     inline void AddString(String* string);
@@ skipping 135 matching lines @@
   void EnsureFillerObjectAtTop();
 
   // Ensure that we have swept all spaces in such a way that we can iterate
   // over all objects.  May cause a GC.
   void MakeHeapIterable();
 
   // Performs garbage collection operation.
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   bool CollectGarbage(
-      GarbageCollector collector, const char* gc_reason,
+      GarbageCollector collector, GarbageCollectionReason gc_reason,
       const char* collector_reason,
       const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
 
   // Performs garbage collection
   // Returns whether there is a chance another major GC could
   // collect more garbage.
   bool PerformGarbageCollection(
       GarbageCollector collector,
       const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
 
@@ skipping 54 matching lines @@
 
   void ConfigureInitialOldGenerationSize();
 
   bool HasLowYoungGenerationAllocationRate();
   bool HasLowOldGenerationAllocationRate();
   double YoungGenerationMutatorUtilization();
   double OldGenerationMutatorUtilization();
 
   void ReduceNewSpaceSize();
 
-  bool TryFinalizeIdleIncrementalMarking(
-      double idle_time_in_ms, size_t size_of_objects,
-      size_t mark_compact_speed_in_bytes_per_ms);
-
   GCIdleTimeHeapState ComputeHeapState();
 
   bool PerformIdleTimeAction(GCIdleTimeAction action,
                              GCIdleTimeHeapState heap_state,
                              double deadline_in_ms);
 
   void IdleNotificationEpilogue(GCIdleTimeAction action,
                                 GCIdleTimeHeapState heap_state, double start_ms,
                                 double deadline_in_ms);
 
   inline void UpdateAllocationsHash(HeapObject* object);
   inline void UpdateAllocationsHash(uint32_t value);
   void PrintAlloctionsHash();
 
   void AddToRingBuffer(const char* string);
   void GetFromRingBuffer(char* buffer);
 
   void CompactRetainedMaps(ArrayList* retained_maps);
 
-  void CollectGarbageOnMemoryPressure(const char* source);
+  void CollectGarbageOnMemoryPressure();
 
   // Attempt to over-approximate the weak closure by marking object groups and
   // implicit references from global handles, but don't atomically complete
   // marking. If we continue to mark incrementally, we might have marked
   // objects that die later.
-  void FinalizeIncrementalMarking(const char* gc_reason);
+  void FinalizeIncrementalMarking(GarbageCollectionReason gc_reason);
 
   // Returns the timer used for a given GC type.
   // - GCScavenger: young generation GC
   // - GCCompactor: full GC
   // - GCFinalzeMC: finalization of incremental full GC
   // - GCFinalizeMCReduceMemory: finalization of incremental full GC with
   // memory reduction
   HistogramTimer* GCTypeTimer(GarbageCollector collector);
 
   // ===========================================================================
@@ skipping 881 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_