v8  5.8.282(node8.0.0)
V8 is Google's open source JavaScript engine
v8-profiler.h
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1 // Copyright 2010 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_V8_PROFILER_H_
6 #define V8_V8_PROFILER_H_
7 
8 #include <unordered_set>
9 #include <vector>
10 #include "v8.h" // NOLINT(build/include)
11 
12 /**
13  * Profiler support for the V8 JavaScript engine.
14  */
15 namespace v8 {
16 
17 class HeapGraphNode;
19 
20 typedef uint32_t SnapshotObjectId;
21 
22 
24  int script_id;
26 };
27 
28 } // namespace v8
29 
30 #ifdef V8_OS_WIN
31 template class V8_EXPORT std::vector<v8::CpuProfileDeoptFrame>;
32 #endif
33 
34 namespace v8 {
35 
37  /** A pointer to a static string owned by v8. */
38  const char* deopt_reason;
40 };
41 
42 } // namespace v8
43 
44 #ifdef V8_OS_WIN
45 template class V8_EXPORT std::vector<v8::CpuProfileDeoptInfo>;
46 #endif
47 
48 namespace v8 {
49 
50 /**
51  * TracingCpuProfiler monitors tracing being enabled/disabled
52  * and emits CpuProfile trace events once v8.cpu_profiler tracing category
53  * is enabled. It has no overhead unless the category is enabled.
54  */
56  public:
58  virtual ~TracingCpuProfiler() = default;
59 
60  protected:
61  TracingCpuProfiler() = default;
62 };
63 
64 // TickSample captures the information collected for each sample.
65 struct TickSample {
66  // Internal profiling (with --prof + tools/$OS-tick-processor) wants to
67  // include the runtime function we're calling. Externally exposed tick
68  // samples don't care.
70 
72  : state(OTHER),
73  pc(nullptr),
75  frames_count(0),
76  has_external_callback(false),
77  update_stats(true) {}
78 
79  /**
80  * Initialize a tick sample from the isolate.
81  * \param isolate The isolate.
82  * \param state Execution state.
83  * \param record_c_entry_frame Include or skip the runtime function.
84  * \param update_stats Whether update the sample to the aggregated stats.
85  * \param use_simulator_reg_state When set to true and V8 is running under a
86  * simulator, the method will use the simulator
87  * register state rather than the one provided
88  * with |state| argument. Otherwise the method
89  * will use provided register |state| as is.
90  */
91  void Init(Isolate* isolate, const v8::RegisterState& state,
92  RecordCEntryFrame record_c_entry_frame, bool update_stats,
93  bool use_simulator_reg_state = true);
94  /**
95  * Get a call stack sample from the isolate.
96  * \param isolate The isolate.
97  * \param state Register state.
98  * \param record_c_entry_frame Include or skip the runtime function.
99  * \param frames Caller allocated buffer to store stack frames.
100  * \param frames_limit Maximum number of frames to capture. The buffer must
101  * be large enough to hold the number of frames.
102  * \param sample_info The sample info is filled up by the function
103  * provides number of actual captured stack frames and
104  * the current VM state.
105  * \param use_simulator_reg_state When set to true and V8 is running under a
106  * simulator, the method will use the simulator
107  * register state rather than the one provided
108  * with |state| argument. Otherwise the method
109  * will use provided register |state| as is.
110  * \note GetStackSample is thread and signal safe and should only be called
111  * when the JS thread is paused or interrupted.
112  * Otherwise the behavior is undefined.
113  */
114  static bool GetStackSample(Isolate* isolate, v8::RegisterState* state,
115  RecordCEntryFrame record_c_entry_frame,
116  void** frames, size_t frames_limit,
117  v8::SampleInfo* sample_info,
118  bool use_simulator_reg_state = true);
119  StateTag state; // The state of the VM.
120  void* pc; // Instruction pointer.
121  union {
122  void* tos; // Top stack value (*sp).
123  void* external_callback_entry;
124  };
125  static const unsigned kMaxFramesCountLog2 = 8;
126  static const unsigned kMaxFramesCount = (1 << kMaxFramesCountLog2) - 1;
127  void* stack[kMaxFramesCount]; // Call stack.
128  unsigned frames_count : kMaxFramesCountLog2; // Number of captured frames.
130  bool update_stats : 1; // Whether the sample should update aggregated stats.
131 };
132 
133 /**
134  * CpuProfileNode represents a node in a call graph.
135  */
137  public:
138  struct LineTick {
139  /** The 1-based number of the source line where the function originates. */
140  int line;
141 
142  /** The count of samples associated with the source line. */
143  unsigned int hit_count;
144  };
145 
146  /** Returns function name (empty string for anonymous functions.) */
147  Local<String> GetFunctionName() const;
148 
149  /**
150  * Returns function name (empty string for anonymous functions.)
151  * The string ownership is *not* passed to the caller. It stays valid until
152  * profile is deleted. The function is thread safe.
153  */
154  const char* GetFunctionNameStr() const;
155 
156  /** Returns id of the script where function is located. */
157  int GetScriptId() const;
158 
159  /** Returns resource name for script from where the function originates. */
160  Local<String> GetScriptResourceName() const;
161 
162  /**
163  * Returns resource name for script from where the function originates.
164  * The string ownership is *not* passed to the caller. It stays valid until
165  * profile is deleted. The function is thread safe.
166  */
167  const char* GetScriptResourceNameStr() const;
168 
169  /**
170  * Returns the number, 1-based, of the line where the function originates.
171  * kNoLineNumberInfo if no line number information is available.
172  */
173  int GetLineNumber() const;
174 
175  /**
176  * Returns 1-based number of the column where the function originates.
177  * kNoColumnNumberInfo if no column number information is available.
178  */
179  int GetColumnNumber() const;
180 
181  /**
182  * Returns the number of the function's source lines that collect the samples.
183  */
184  unsigned int GetHitLineCount() const;
185 
186  /** Returns the set of source lines that collect the samples.
187  * The caller allocates buffer and responsible for releasing it.
188  * True if all available entries are copied, otherwise false.
189  * The function copies nothing if buffer is not large enough.
190  */
191  bool GetLineTicks(LineTick* entries, unsigned int length) const;
192 
193  /** Returns bailout reason for the function
194  * if the optimization was disabled for it.
195  */
196  const char* GetBailoutReason() const;
197 
198  /**
199  * Returns the count of samples where the function was currently executing.
200  */
201  unsigned GetHitCount() const;
202 
203  /** Returns function entry UID. */
205  "Use GetScriptId, GetLineNumber, and GetColumnNumber instead.",
206  unsigned GetCallUid() const);
207 
208  /** Returns id of the node. The id is unique within the tree */
209  unsigned GetNodeId() const;
210 
211  /** Returns child nodes count of the node. */
212  int GetChildrenCount() const;
213 
214  /** Retrieves a child node by index. */
215  const CpuProfileNode* GetChild(int index) const;
216 
217  /** Retrieves deopt infos for the node. */
218  const std::vector<CpuProfileDeoptInfo>& GetDeoptInfos() const;
219 
222 };
223 
224 
225 /**
226  * CpuProfile contains a CPU profile in a form of top-down call tree
227  * (from main() down to functions that do all the work).
228  */
230  public:
231  /** Returns CPU profile title. */
232  Local<String> GetTitle() const;
233 
234  /** Returns the root node of the top down call tree. */
235  const CpuProfileNode* GetTopDownRoot() const;
236 
237  /**
238  * Returns number of samples recorded. The samples are not recorded unless
239  * |record_samples| parameter of CpuProfiler::StartCpuProfiling is true.
240  */
241  int GetSamplesCount() const;
242 
243  /**
244  * Returns profile node corresponding to the top frame the sample at
245  * the given index.
246  */
247  const CpuProfileNode* GetSample(int index) const;
248 
249  /**
250  * Returns the timestamp of the sample. The timestamp is the number of
251  * microseconds since some unspecified starting point.
252  * The point is equal to the starting point used by GetStartTime.
253  */
254  int64_t GetSampleTimestamp(int index) const;
255 
256  /**
257  * Returns time when the profile recording was started (in microseconds)
258  * since some unspecified starting point.
259  */
260  int64_t GetStartTime() const;
261 
262  /**
263  * Returns time when the profile recording was stopped (in microseconds)
264  * since some unspecified starting point.
265  * The point is equal to the starting point used by GetStartTime.
266  */
267  int64_t GetEndTime() const;
268 
269  /**
270  * Deletes the profile and removes it from CpuProfiler's list.
271  * All pointers to nodes previously returned become invalid.
272  */
273  void Delete();
274 };
275 
276 /**
277  * Interface for controlling CPU profiling. Instance of the
278  * profiler can be created using v8::CpuProfiler::New method.
279  */
281  public:
282  /**
283  * Creates a new CPU profiler for the |isolate|. The isolate must be
284  * initialized. The profiler object must be disposed after use by calling
285  * |Dispose| method.
286  */
287  static CpuProfiler* New(Isolate* isolate);
288 
289  /**
290  * Disposes the CPU profiler object.
291  */
292  void Dispose();
293 
294  /**
295  * Changes default CPU profiler sampling interval to the specified number
296  * of microseconds. Default interval is 1000us. This method must be called
297  * when there are no profiles being recorded.
298  */
299  void SetSamplingInterval(int us);
300 
301  /**
302  * Starts collecting CPU profile. Title may be an empty string. It
303  * is allowed to have several profiles being collected at
304  * once. Attempts to start collecting several profiles with the same
305  * title are silently ignored. While collecting a profile, functions
306  * from all security contexts are included in it. The token-based
307  * filtering is only performed when querying for a profile.
308  *
309  * |record_samples| parameter controls whether individual samples should
310  * be recorded in addition to the aggregated tree.
311  */
312  void StartProfiling(Local<String> title, bool record_samples = false);
313 
314  /**
315  * Stops collecting CPU profile with a given title and returns it.
316  * If the title given is empty, finishes the last profile started.
317  */
318  CpuProfile* StopProfiling(Local<String> title);
319 
320  /**
321  * Force collection of a sample. Must be called on the VM thread.
322  * Recording the forced sample does not contribute to the aggregated
323  * profile statistics.
324  */
325  void CollectSample();
326 
327  /**
328  * Tells the profiler whether the embedder is idle.
329  */
330  void SetIdle(bool is_idle);
331 
332  private:
333  CpuProfiler();
334  ~CpuProfiler();
335  CpuProfiler(const CpuProfiler&);
336  CpuProfiler& operator=(const CpuProfiler&);
337 };
338 
339 
340 /**
341  * HeapSnapshotEdge represents a directed connection between heap
342  * graph nodes: from retainers to retained nodes.
343  */
345  public:
346  enum Type {
347  kContextVariable = 0, // A variable from a function context.
348  kElement = 1, // An element of an array.
349  kProperty = 2, // A named object property.
350  kInternal = 3, // A link that can't be accessed from JS,
351  // thus, its name isn't a real property name
352  // (e.g. parts of a ConsString).
353  kHidden = 4, // A link that is needed for proper sizes
354  // calculation, but may be hidden from user.
355  kShortcut = 5, // A link that must not be followed during
356  // sizes calculation.
357  kWeak = 6 // A weak reference (ignored by the GC).
358  };
359 
360  /** Returns edge type (see HeapGraphEdge::Type). */
361  Type GetType() const;
362 
363  /**
364  * Returns edge name. This can be a variable name, an element index, or
365  * a property name.
366  */
367  Local<Value> GetName() const;
368 
369  /** Returns origin node. */
370  const HeapGraphNode* GetFromNode() const;
371 
372  /** Returns destination node. */
373  const HeapGraphNode* GetToNode() const;
374 };
375 
376 
377 /**
378  * HeapGraphNode represents a node in a heap graph.
379  */
381  public:
382  enum Type {
383  kHidden = 0, // Hidden node, may be filtered when shown to user.
384  kArray = 1, // An array of elements.
385  kString = 2, // A string.
386  kObject = 3, // A JS object (except for arrays and strings).
387  kCode = 4, // Compiled code.
388  kClosure = 5, // Function closure.
389  kRegExp = 6, // RegExp.
390  kHeapNumber = 7, // Number stored in the heap.
391  kNative = 8, // Native object (not from V8 heap).
392  kSynthetic = 9, // Synthetic object, usualy used for grouping
393  // snapshot items together.
394  kConsString = 10, // Concatenated string. A pair of pointers to strings.
395  kSlicedString = 11, // Sliced string. A fragment of another string.
396  kSymbol = 12 // A Symbol (ES6).
397  };
398 
399  /** Returns node type (see HeapGraphNode::Type). */
400  Type GetType() const;
401 
402  /**
403  * Returns node name. Depending on node's type this can be the name
404  * of the constructor (for objects), the name of the function (for
405  * closures), string value, or an empty string (for compiled code).
406  */
407  Local<String> GetName() const;
408 
409  /**
410  * Returns node id. For the same heap object, the id remains the same
411  * across all snapshots.
412  */
413  SnapshotObjectId GetId() const;
414 
415  /** Returns node's own size, in bytes. */
416  size_t GetShallowSize() const;
417 
418  /** Returns child nodes count of the node. */
419  int GetChildrenCount() const;
420 
421  /** Retrieves a child by index. */
422  const HeapGraphEdge* GetChild(int index) const;
423 };
424 
425 
426 /**
427  * An interface for exporting data from V8, using "push" model.
428  */
429 class V8_EXPORT OutputStream { // NOLINT
430  public:
431  enum WriteResult {
433  kAbort = 1
434  };
435  virtual ~OutputStream() {}
436  /** Notify about the end of stream. */
437  virtual void EndOfStream() = 0;
438  /** Get preferred output chunk size. Called only once. */
439  virtual int GetChunkSize() { return 1024; }
440  /**
441  * Writes the next chunk of snapshot data into the stream. Writing
442  * can be stopped by returning kAbort as function result. EndOfStream
443  * will not be called in case writing was aborted.
444  */
445  virtual WriteResult WriteAsciiChunk(char* data, int size) = 0;
446  /**
447  * Writes the next chunk of heap stats data into the stream. Writing
448  * can be stopped by returning kAbort as function result. EndOfStream
449  * will not be called in case writing was aborted.
450  */
451  virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate* data, int count) {
452  return kAbort;
453  }
454 };
455 
456 
457 /**
458  * HeapSnapshots record the state of the JS heap at some moment.
459  */
461  public:
463  kJSON = 0 // See format description near 'Serialize' method.
464  };
465 
466  /** Returns the root node of the heap graph. */
467  const HeapGraphNode* GetRoot() const;
468 
469  /** Returns a node by its id. */
470  const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
471 
472  /** Returns total nodes count in the snapshot. */
473  int GetNodesCount() const;
474 
475  /** Returns a node by index. */
476  const HeapGraphNode* GetNode(int index) const;
477 
478  /** Returns a max seen JS object Id. */
480 
481  /**
482  * Deletes the snapshot and removes it from HeapProfiler's list.
483  * All pointers to nodes, edges and paths previously returned become
484  * invalid.
485  */
486  void Delete();
487 
488  /**
489  * Prepare a serialized representation of the snapshot. The result
490  * is written into the stream provided in chunks of specified size.
491  * The total length of the serialized snapshot is unknown in
492  * advance, it can be roughly equal to JS heap size (that means,
493  * it can be really big - tens of megabytes).
494  *
495  * For the JSON format, heap contents are represented as an object
496  * with the following structure:
497  *
498  * {
499  * snapshot: {
500  * title: "...",
501  * uid: nnn,
502  * meta: { meta-info },
503  * node_count: nnn,
504  * edge_count: nnn
505  * },
506  * nodes: [nodes array],
507  * edges: [edges array],
508  * strings: [strings array]
509  * }
510  *
511  * Nodes reference strings, other nodes, and edges by their indexes
512  * in corresponding arrays.
513  */
514  void Serialize(OutputStream* stream,
515  SerializationFormat format = kJSON) const;
516 };
517 
518 
519 /**
520  * An interface for reporting progress and controlling long-running
521  * activities.
522  */
523 class V8_EXPORT ActivityControl { // NOLINT
524  public:
527  kAbort = 1
528  };
529  virtual ~ActivityControl() {}
530  /**
531  * Notify about current progress. The activity can be stopped by
532  * returning kAbort as the callback result.
533  */
534  virtual ControlOption ReportProgressValue(int done, int total) = 0;
535 };
536 
537 
538 /**
539  * AllocationProfile is a sampled profile of allocations done by the program.
540  * This is structured as a call-graph.
541  */
543  public:
544  struct Allocation {
545  /**
546  * Size of the sampled allocation object.
547  */
549 
550  /**
551  * The number of objects of such size that were sampled.
552  */
553  unsigned int count;
554  };
555 
556  /**
557  * Represents a node in the call-graph.
558  */
559  struct Node {
560  /**
561  * Name of the function. May be empty for anonymous functions or if the
562  * script corresponding to this function has been unloaded.
563  */
564  Local<String> name;
565 
566  /**
567  * Name of the script containing the function. May be empty if the script
568  * name is not available, or if the script has been unloaded.
569  */
571 
572  /**
573  * id of the script where the function is located. May be equal to
574  * v8::UnboundScript::kNoScriptId in cases where the script doesn't exist.
575  */
577 
578  /**
579  * Start position of the function in the script.
580  */
582 
583  /**
584  * 1-indexed line number where the function starts. May be
585  * kNoLineNumberInfo if no line number information is available.
586  */
588 
589  /**
590  * 1-indexed column number where the function starts. May be
591  * kNoColumnNumberInfo if no line number information is available.
592  */
594 
595  /**
596  * List of callees called from this node for which we have sampled
597  * allocations. The lifetime of the children is scoped to the containing
598  * AllocationProfile.
599  */
600  std::vector<Node*> children;
601 
602  /**
603  * List of self allocations done by this node in the call-graph.
604  */
605  std::vector<Allocation> allocations;
606  };
607 
608  /**
609  * Returns the root node of the call-graph. The root node corresponds to an
610  * empty JS call-stack. The lifetime of the returned Node* is scoped to the
611  * containing AllocationProfile.
612  */
613  virtual Node* GetRootNode() = 0;
614 
615  virtual ~AllocationProfile() {}
616 
619 };
620 
621 
622 /**
623  * Interface for controlling heap profiling. Instance of the
624  * profiler can be retrieved using v8::Isolate::GetHeapProfiler.
625  */
627  public:
631  };
632 
633  typedef std::unordered_set<const v8::PersistentBase<v8::Value>*>
637  typedef std::vector<std::pair<const v8::PersistentBase<v8::Value>*,
638  const v8::PersistentBase<v8::Value>*>>
640 
641  struct RetainerInfos {
644  };
645 
646  /**
647  * Callback function invoked to retrieve all RetainerInfos from the embedder.
648  */
649  typedef RetainerInfos (*GetRetainerInfosCallback)(v8::Isolate* isolate);
650 
651  /**
652  * Callback function invoked for obtaining RetainedObjectInfo for
653  * the given JavaScript wrapper object. It is prohibited to enter V8
654  * while the callback is running: only getters on the handle and
655  * GetPointerFromInternalField on the objects are allowed.
656  */
657  typedef RetainedObjectInfo* (*WrapperInfoCallback)(uint16_t class_id,
658  Local<Value> wrapper);
659 
660  /** Returns the number of snapshots taken. */
661  int GetSnapshotCount();
662 
663  /** Returns a snapshot by index. */
664  const HeapSnapshot* GetHeapSnapshot(int index);
665 
666  /**
667  * Returns SnapshotObjectId for a heap object referenced by |value| if
668  * it has been seen by the heap profiler, kUnknownObjectId otherwise.
669  */
670  SnapshotObjectId GetObjectId(Local<Value> value);
671 
672  /**
673  * Returns heap object with given SnapshotObjectId if the object is alive,
674  * otherwise empty handle is returned.
675  */
677 
678  /**
679  * Clears internal map from SnapshotObjectId to heap object. The new objects
680  * will not be added into it unless a heap snapshot is taken or heap object
681  * tracking is kicked off.
682  */
683  void ClearObjectIds();
684 
685  /**
686  * A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
687  * it in case heap profiler cannot find id for the object passed as
688  * parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
689  */
691 
692  /**
693  * Callback interface for retrieving user friendly names of global objects.
694  */
696  public:
697  /**
698  * Returns name to be used in the heap snapshot for given node. Returned
699  * string must stay alive until snapshot collection is completed.
700  */
701  virtual const char* GetName(Local<Object> object) = 0;
702 
703  protected:
704  virtual ~ObjectNameResolver() {}
705  };
706 
707  /**
708  * Takes a heap snapshot and returns it.
709  */
711  ActivityControl* control = NULL,
712  ObjectNameResolver* global_object_name_resolver = NULL);
713 
714  /**
715  * Starts tracking of heap objects population statistics. After calling
716  * this method, all heap objects relocations done by the garbage collector
717  * are being registered.
718  *
719  * |track_allocations| parameter controls whether stack trace of each
720  * allocation in the heap will be recorded and reported as part of
721  * HeapSnapshot.
722  */
723  void StartTrackingHeapObjects(bool track_allocations = false);
724 
725  /**
726  * Adds a new time interval entry to the aggregated statistics array. The
727  * time interval entry contains information on the current heap objects
728  * population size. The method also updates aggregated statistics and
729  * reports updates for all previous time intervals via the OutputStream
730  * object. Updates on each time interval are provided as a stream of the
731  * HeapStatsUpdate structure instances.
732  * If |timestamp_us| is supplied, timestamp of the new entry will be written
733  * into it. The return value of the function is the last seen heap object Id.
734  *
735  * StartTrackingHeapObjects must be called before the first call to this
736  * method.
737  */
739  int64_t* timestamp_us = NULL);
740 
741  /**
742  * Stops tracking of heap objects population statistics, cleans up all
743  * collected data. StartHeapObjectsTracking must be called again prior to
744  * calling GetHeapStats next time.
745  */
747 
748  /**
749  * Starts gathering a sampling heap profile. A sampling heap profile is
750  * similar to tcmalloc's heap profiler and Go's mprof. It samples object
751  * allocations and builds an online 'sampling' heap profile. At any point in
752  * time, this profile is expected to be a representative sample of objects
753  * currently live in the system. Each sampled allocation includes the stack
754  * trace at the time of allocation, which makes this really useful for memory
755  * leak detection.
756  *
757  * This mechanism is intended to be cheap enough that it can be used in
758  * production with minimal performance overhead.
759  *
760  * Allocations are sampled using a randomized Poisson process. On average, one
761  * allocation will be sampled every |sample_interval| bytes allocated. The
762  * |stack_depth| parameter controls the maximum number of stack frames to be
763  * captured on each allocation.
764  *
765  * NOTE: This is a proof-of-concept at this point. Right now we only sample
766  * newspace allocations. Support for paged space allocation (e.g. pre-tenured
767  * objects, large objects, code objects, etc.) and native allocations
768  * doesn't exist yet, but is anticipated in the future.
769  *
770  * Objects allocated before the sampling is started will not be included in
771  * the profile.
772  *
773  * Returns false if a sampling heap profiler is already running.
774  */
775  bool StartSamplingHeapProfiler(uint64_t sample_interval = 512 * 1024,
776  int stack_depth = 16,
778 
779  /**
780  * Stops the sampling heap profile and discards the current profile.
781  */
783 
784  /**
785  * Returns the sampled profile of allocations allocated (and still live) since
786  * StartSamplingHeapProfiler was called. The ownership of the pointer is
787  * transfered to the caller. Returns nullptr if sampling heap profiler is not
788  * active.
789  */
791 
792  /**
793  * Deletes all snapshots taken. All previously returned pointers to
794  * snapshots and their contents become invalid after this call.
795  */
796  void DeleteAllHeapSnapshots();
797 
798  /** Binds a callback to embedder's class ID. */
800  uint16_t class_id,
801  WrapperInfoCallback callback);
802 
803  void SetGetRetainerInfosCallback(GetRetainerInfosCallback callback);
804 
805  /**
806  * Default value of persistent handle class ID. Must not be used to
807  * define a class. Can be used to reset a class of a persistent
808  * handle.
809  */
810  static const uint16_t kPersistentHandleNoClassId = 0;
811 
812  /** Returns memory used for profiler internal data and snapshots. */
814 
815  /**
816  * Sets a RetainedObjectInfo for an object group (see V8::SetObjectGroupId).
817  */
819 
820  private:
821  HeapProfiler();
822  ~HeapProfiler();
823  HeapProfiler(const HeapProfiler&);
824  HeapProfiler& operator=(const HeapProfiler&);
825 };
826 
827 /**
828  * Interface for providing information about embedder's objects
829  * held by global handles. This information is reported in two ways:
830  *
831  * 1. When calling AddObjectGroup, an embedder may pass
832  * RetainedObjectInfo instance describing the group. To collect
833  * this information while taking a heap snapshot, V8 calls GC
834  * prologue and epilogue callbacks.
835  *
836  * 2. When a heap snapshot is collected, V8 additionally
837  * requests RetainedObjectInfos for persistent handles that
838  * were not previously reported via AddObjectGroup.
839  *
840  * Thus, if an embedder wants to provide information about native
841  * objects for heap snapshots, it can do it in a GC prologue
842  * handler, and / or by assigning wrapper class ids in the following way:
843  *
844  * 1. Bind a callback to class id by calling SetWrapperClassInfoProvider.
845  * 2. Call SetWrapperClassId on certain persistent handles.
846  *
847  * V8 takes ownership of RetainedObjectInfo instances passed to it and
848  * keeps them alive only during snapshot collection. Afterwards, they
849  * are freed by calling the Dispose class function.
850  */
851 class V8_EXPORT RetainedObjectInfo { // NOLINT
852  public:
853  /** Called by V8 when it no longer needs an instance. */
854  virtual void Dispose() = 0;
855 
856  /** Returns whether two instances are equivalent. */
857  virtual bool IsEquivalent(RetainedObjectInfo* other) = 0;
858 
859  /**
860  * Returns hash value for the instance. Equivalent instances
861  * must have the same hash value.
862  */
863  virtual intptr_t GetHash() = 0;
864 
865  /**
866  * Returns human-readable label. It must be a null-terminated UTF-8
867  * encoded string. V8 copies its contents during a call to GetLabel.
868  */
869  virtual const char* GetLabel() = 0;
870 
871  /**
872  * Returns human-readable group label. It must be a null-terminated UTF-8
873  * encoded string. V8 copies its contents during a call to GetGroupLabel.
874  * Heap snapshot generator will collect all the group names, create
875  * top level entries with these names and attach the objects to the
876  * corresponding top level group objects. There is a default
877  * implementation which is required because embedders don't have their
878  * own implementation yet.
879  */
880  virtual const char* GetGroupLabel() { return GetLabel(); }
881 
882  /**
883  * Returns element count in case if a global handle retains
884  * a subgraph by holding one of its nodes.
885  */
886  virtual intptr_t GetElementCount() { return -1; }
887 
888  /** Returns embedder's object size in bytes. */
889  virtual intptr_t GetSizeInBytes() { return -1; }
890 
891  protected:
893  virtual ~RetainedObjectInfo() {}
894 
895  private:
896  RetainedObjectInfo(const RetainedObjectInfo&);
897  RetainedObjectInfo& operator=(const RetainedObjectInfo&);
898 };
899 
900 
901 /**
902  * A struct for exporting HeapStats data from V8, using "push" model.
903  * See HeapProfiler::GetHeapStats.
904  */
906  HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
907  : index(index), count(count), size(size) { }
908  uint32_t index; // Index of the time interval that was changed.
909  uint32_t count; // New value of count field for the interval with this index.
910  uint32_t size; // New value of size field for the interval with this index.
911 };
912 
913 
914 } // namespace v8
915 
916 
917 #endif // V8_V8_PROFILER_H_
void DeleteAllHeapSnapshots()
Local< Value > GetName() const
const char * GetFunctionNameStr() const
const HeapGraphNode * GetFromNode() const
static bool GetStackSample(Isolate *isolate, v8::RegisterState *state, RecordCEntryFrame record_c_entry_frame, void **frames, size_t frames_limit, v8::SampleInfo *sample_info, bool use_simulator_reg_state=true)
void StopTrackingHeapObjects()
Local< String > GetScriptResourceName() const
int64_t GetSampleTimestamp(int index) const
void SetWrapperClassInfoProvider(uint16_t class_id, WrapperInfoCallback callback)
virtual intptr_t GetHash()=0
std::vector< std::pair< v8::RetainedObjectInfo *, RetainerChildren > > RetainerGroups
Definition: v8-profiler.h:636
const HeapGraphNode * GetToNode() const
Definition: v8.h:1937
void SetGetRetainerInfosCallback(GetRetainerInfosCallback callback)
Local< String > GetTitle() const
virtual ~OutputStream()
Definition: v8-profiler.h:435
StateTag
Definition: v8.h:1647
Definition: v8.h:1647
SnapshotObjectId GetId() const
int64_t GetStartTime() const
TracingCpuProfiler()=default
std::vector< Node * > children
Definition: v8-profiler.h:600
static const int kNoColumnInfo
Definition: v8.h:1524
static const int kNoColumnNumberInfo
Definition: v8-profiler.h:618
CpuProfile * StopProfiling(Local< String > title)
unsigned GetNodeId() const
static std::unique_ptr< TracingCpuProfiler > Create(Isolate *)
SnapshotObjectId GetObjectId(Local< Value > value)
const HeapSnapshot * TakeHeapSnapshot(ActivityControl *control=NULL, ObjectNameResolver *global_object_name_resolver=NULL)
size_t GetShallowSize() const
static const int kNoLineNumberInfo
Definition: v8.h:1523
void SetSamplingInterval(int us)
const HeapGraphEdge * GetChild(int index) const
virtual ControlOption ReportProgressValue(int done, int total)=0
SnapshotObjectId GetHeapStats(OutputStream *stream, int64_t *timestamp_us=NULL)
StateTag state
Definition: v8-profiler.h:119
void StartProfiling(Local< String > title, bool record_samples=false)
#define V8_DEPRECATE_SOON(message, declarator)
Definition: v8config.h:351
int GetChildrenCount() const
virtual bool IsEquivalent(RetainedObjectInfo *other)=0
const HeapGraphNode * GetRoot() const
void * stack[kMaxFramesCount]
Definition: v8-profiler.h:127
static const int kNoColumnNumberInfo
Definition: v8-profiler.h:221
SnapshotObjectId GetMaxSnapshotJSObjectId() const
Definition: libplatform.h:12
virtual int GetChunkSize()
Definition: v8-profiler.h:439
static const uint16_t kPersistentHandleNoClassId
Definition: v8-profiler.h:810
virtual const char * GetLabel()=0
int64_t GetEndTime() const
HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
Definition: v8-profiler.h:906
Type GetType() const
std::vector< CpuProfileDeoptFrame > stack
Definition: v8-profiler.h:39
virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate *data, int count)
Definition: v8-profiler.h:451
std::vector< std::pair< const v8::PersistentBase< v8::Value > *, const v8::PersistentBase< v8::Value > * > > RetainerEdges
Definition: v8-profiler.h:639
const CpuProfileNode * GetChild(int index) const
virtual ~RetainedObjectInfo()
Definition: v8-profiler.h:893
void StopSamplingHeapProfiler()
const std::vector< CpuProfileDeoptInfo > & GetDeoptInfos() const
size_t GetProfilerMemorySize()
void CollectSample()
virtual ~ActivityControl()
Definition: v8-profiler.h:529
const CpuProfileNode * GetTopDownRoot() const
bool GetLineTicks(LineTick *entries, unsigned int length) const
static const int kNoLineNumberInfo
Definition: v8-profiler.h:617
const char * GetScriptResourceNameStr() const
void SetRetainedObjectInfo(UniqueId id, RetainedObjectInfo *info)
int GetScriptId() const
std::vector< Allocation > allocations
Definition: v8-profiler.h:605
int GetSamplesCount() const
virtual ~AllocationProfile()
Definition: v8-profiler.h:615
Local< Value > FindObjectById(SnapshotObjectId id)
void Serialize(OutputStream *stream, SerializationFormat format=kJSON) const
virtual WriteResult WriteAsciiChunk(char *data, int size)=0
const HeapGraphNode * GetNode(int index) const
virtual void Dispose()=0
const char * deopt_reason
Definition: v8-profiler.h:38
unsigned int GetHitLineCount() const
bool has_external_callback
Definition: v8-profiler.h:129
uint32_t SnapshotObjectId
Definition: v8-profiler.h:18
int GetNodesCount() const
int GetChildrenCount() const
const CpuProfileNode * GetSample(int index) const
Local< String > GetName() const
AllocationProfile * GetAllocationProfile()
int GetColumnNumber() const
virtual Node * GetRootNode()=0
bool StartSamplingHeapProfiler(uint64_t sample_interval=512 *1024, int stack_depth=16, SamplingFlags flags=kSamplingNoFlags)
unsigned frames_count
Definition: v8-profiler.h:128
virtual intptr_t GetElementCount()
Definition: v8-profiler.h:886
unsigned GetHitCount() const
static const unsigned kMaxFramesCountLog2
Definition: v8-profiler.h:125
void StartTrackingHeapObjects(bool track_allocations=false)
Type GetType() const
void Init(Isolate *isolate, const v8::RegisterState &state, RecordCEntryFrame record_c_entry_frame, bool update_stats, bool use_simulator_reg_state=true)
void SetIdle(bool is_idle)
virtual ~TracingCpuProfiler()=default
virtual void EndOfStream()=0
static const unsigned kMaxFramesCount
Definition: v8-profiler.h:126
static const int kNoLineNumberInfo
Definition: v8-profiler.h:220
virtual intptr_t GetSizeInBytes()
Definition: v8-profiler.h:889
Local< String > script_name
Definition: v8-profiler.h:570
virtual const char * GetName(Local< Object > object)=0
const HeapGraphNode * GetNodeById(SnapshotObjectId id) const
const HeapSnapshot * GetHeapSnapshot(int index)
#define V8_EXPORT
Definition: v8.h:56
const char * GetBailoutReason() const
static CpuProfiler * New(Isolate *isolate)
virtual const char * GetGroupLabel()
Definition: v8-profiler.h:880
Local< String > GetFunctionName() const
int GetLineNumber() const
static const SnapshotObjectId kUnknownObjectId
Definition: v8-profiler.h:690