v8  3.28.71(node0.12.18)
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 "v8.h"
9 
10 /**
11  * Profiler support for the V8 JavaScript engine.
12  */
13 namespace v8 {
14 
15 class HeapGraphNode;
17 
18 typedef uint32_t SnapshotObjectId;
19 
20 /**
21  * CpuProfileNode represents a node in a call graph.
22  */
24  public:
25  /** Returns function name (empty string for anonymous functions.) */
26  Handle<String> GetFunctionName() const;
27 
28  /** Returns id of the script where function is located. */
29  int GetScriptId() const;
30 
31  /** Returns resource name for script from where the function originates. */
32  Handle<String> GetScriptResourceName() const;
33 
34  /**
35  * Returns the number, 1-based, of the line where the function originates.
36  * kNoLineNumberInfo if no line number information is available.
37  */
38  int GetLineNumber() const;
39 
40  /**
41  * Returns 1-based number of the column where the function originates.
42  * kNoColumnNumberInfo if no column number information is available.
43  */
44  int GetColumnNumber() const;
45 
46  /** Returns bailout reason for the function
47  * if the optimization was disabled for it.
48  */
49  const char* GetBailoutReason() const;
50 
51  /**
52  * Returns the count of samples where the function was currently executing.
53  */
54  unsigned GetHitCount() const;
55 
56  /** Returns function entry UID. */
57  unsigned GetCallUid() const;
58 
59  /** Returns id of the node. The id is unique within the tree */
60  unsigned GetNodeId() const;
61 
62  /** Returns child nodes count of the node. */
63  int GetChildrenCount() const;
64 
65  /** Retrieves a child node by index. */
66  const CpuProfileNode* GetChild(int index) const;
67 
70 };
71 
72 
73 /**
74  * CpuProfile contains a CPU profile in a form of top-down call tree
75  * (from main() down to functions that do all the work).
76  */
78  public:
79  /** Returns CPU profile title. */
80  Handle<String> GetTitle() const;
81 
82  /** Returns the root node of the top down call tree. */
83  const CpuProfileNode* GetTopDownRoot() const;
84 
85  /**
86  * Returns number of samples recorded. The samples are not recorded unless
87  * |record_samples| parameter of CpuProfiler::StartCpuProfiling is true.
88  */
89  int GetSamplesCount() const;
90 
91  /**
92  * Returns profile node corresponding to the top frame the sample at
93  * the given index.
94  */
95  const CpuProfileNode* GetSample(int index) const;
96 
97  /**
98  * Returns the timestamp of the sample. The timestamp is the number of
99  * microseconds since some unspecified starting point.
100  * The point is equal to the starting point used by GetStartTime.
101  */
102  int64_t GetSampleTimestamp(int index) const;
103 
104  /**
105  * Returns time when the profile recording was started (in microseconds)
106  * since some unspecified starting point.
107  */
108  int64_t GetStartTime() const;
109 
110  /**
111  * Returns time when the profile recording was stopped (in microseconds)
112  * since some unspecified starting point.
113  * The point is equal to the starting point used by GetStartTime.
114  */
115  int64_t GetEndTime() const;
116 
117  /**
118  * Deletes the profile and removes it from CpuProfiler's list.
119  * All pointers to nodes previously returned become invalid.
120  */
121  void Delete();
122 };
123 
124 
125 /**
126  * Interface for controlling CPU profiling. Instance of the
127  * profiler can be retrieved using v8::Isolate::GetCpuProfiler.
128  */
130  public:
131  /**
132  * Changes default CPU profiler sampling interval to the specified number
133  * of microseconds. Default interval is 1000us. This method must be called
134  * when there are no profiles being recorded.
135  */
136  void SetSamplingInterval(int us);
137 
138  /**
139  * Starts collecting CPU profile. Title may be an empty string. It
140  * is allowed to have several profiles being collected at
141  * once. Attempts to start collecting several profiles with the same
142  * title are silently ignored. While collecting a profile, functions
143  * from all security contexts are included in it. The token-based
144  * filtering is only performed when querying for a profile.
145  *
146  * |record_samples| parameter controls whether individual samples should
147  * be recorded in addition to the aggregated tree.
148  */
149  void StartProfiling(Handle<String> title, bool record_samples = false);
150 
151  /** Deprecated. Use StartProfiling instead. */
152  V8_DEPRECATED("Use StartProfiling",
153  void StartCpuProfiling(Handle<String> title,
154  bool record_samples = false));
155 
156  /**
157  * Stops collecting CPU profile with a given title and returns it.
158  * If the title given is empty, finishes the last profile started.
159  */
160  CpuProfile* StopProfiling(Handle<String> title);
161 
162  /** Deprecated. Use StopProfiling instead. */
163  V8_DEPRECATED("Use StopProfiling",
164  const CpuProfile* StopCpuProfiling(Handle<String> title));
165 
166  /**
167  * Tells the profiler whether the embedder is idle.
168  */
169  void SetIdle(bool is_idle);
170 
171  private:
172  CpuProfiler();
173  ~CpuProfiler();
174  CpuProfiler(const CpuProfiler&);
175  CpuProfiler& operator=(const CpuProfiler&);
176 };
177 
178 
179 /**
180  * HeapSnapshotEdge represents a directed connection between heap
181  * graph nodes: from retainers to retained nodes.
182  */
184  public:
185  enum Type {
186  kContextVariable = 0, // A variable from a function context.
187  kElement = 1, // An element of an array.
188  kProperty = 2, // A named object property.
189  kInternal = 3, // A link that can't be accessed from JS,
190  // thus, its name isn't a real property name
191  // (e.g. parts of a ConsString).
192  kHidden = 4, // A link that is needed for proper sizes
193  // calculation, but may be hidden from user.
194  kShortcut = 5, // A link that must not be followed during
195  // sizes calculation.
196  kWeak = 6 // A weak reference (ignored by the GC).
197  };
198 
199  /** Returns edge type (see HeapGraphEdge::Type). */
200  Type GetType() const;
201 
202  /**
203  * Returns edge name. This can be a variable name, an element index, or
204  * a property name.
205  */
206  Handle<Value> GetName() const;
207 
208  /** Returns origin node. */
209  const HeapGraphNode* GetFromNode() const;
210 
211  /** Returns destination node. */
212  const HeapGraphNode* GetToNode() const;
213 };
214 
215 
216 /**
217  * HeapGraphNode represents a node in a heap graph.
218  */
220  public:
221  enum Type {
222  kHidden = 0, // Hidden node, may be filtered when shown to user.
223  kArray = 1, // An array of elements.
224  kString = 2, // A string.
225  kObject = 3, // A JS object (except for arrays and strings).
226  kCode = 4, // Compiled code.
227  kClosure = 5, // Function closure.
228  kRegExp = 6, // RegExp.
229  kHeapNumber = 7, // Number stored in the heap.
230  kNative = 8, // Native object (not from V8 heap).
231  kSynthetic = 9, // Synthetic object, usualy used for grouping
232  // snapshot items together.
233  kConsString = 10, // Concatenated string. A pair of pointers to strings.
234  kSlicedString = 11, // Sliced string. A fragment of another string.
235  kSymbol = 12 // A Symbol (ES6).
236  };
237 
238  /** Returns node type (see HeapGraphNode::Type). */
239  Type GetType() const;
240 
241  /**
242  * Returns node name. Depending on node's type this can be the name
243  * of the constructor (for objects), the name of the function (for
244  * closures), string value, or an empty string (for compiled code).
245  */
246  Handle<String> GetName() const;
247 
248  /**
249  * Returns node id. For the same heap object, the id remains the same
250  * across all snapshots.
251  */
252  SnapshotObjectId GetId() const;
253 
254  /** Returns node's own size, in bytes. */
255  V8_DEPRECATED("Use GetShallowSize instead",
256  int GetSelfSize() const);
257 
258  /** Returns node's own size, in bytes. */
259  size_t GetShallowSize() const;
260 
261  /** Returns child nodes count of the node. */
262  int GetChildrenCount() const;
263 
264  /** Retrieves a child by index. */
265  const HeapGraphEdge* GetChild(int index) const;
266 };
267 
268 
269 /**
270  * An interface for exporting data from V8, using "push" model.
271  */
272 class V8_EXPORT OutputStream { // NOLINT
273  public:
274  enum WriteResult {
276  kAbort = 1
277  };
278  virtual ~OutputStream() {}
279  /** Notify about the end of stream. */
280  virtual void EndOfStream() = 0;
281  /** Get preferred output chunk size. Called only once. */
282  virtual int GetChunkSize() { return 1024; }
283  /**
284  * Writes the next chunk of snapshot data into the stream. Writing
285  * can be stopped by returning kAbort as function result. EndOfStream
286  * will not be called in case writing was aborted.
287  */
288  virtual WriteResult WriteAsciiChunk(char* data, int size) = 0;
289  /**
290  * Writes the next chunk of heap stats data into the stream. Writing
291  * can be stopped by returning kAbort as function result. EndOfStream
292  * will not be called in case writing was aborted.
293  */
294  virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate* data, int count) {
295  return kAbort;
296  }
297 };
298 
299 
300 /**
301  * HeapSnapshots record the state of the JS heap at some moment.
302  */
304  public:
306  kJSON = 0 // See format description near 'Serialize' method.
307  };
308 
309  /** Returns heap snapshot UID (assigned by the profiler.) */
310  unsigned GetUid() const;
311 
312  /** Returns heap snapshot title. */
313  Handle<String> GetTitle() const;
314 
315  /** Returns the root node of the heap graph. */
316  const HeapGraphNode* GetRoot() const;
317 
318  /** Returns a node by its id. */
319  const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
320 
321  /** Returns total nodes count in the snapshot. */
322  int GetNodesCount() const;
323 
324  /** Returns a node by index. */
325  const HeapGraphNode* GetNode(int index) const;
326 
327  /** Returns a max seen JS object Id. */
329 
330  /**
331  * Deletes the snapshot and removes it from HeapProfiler's list.
332  * All pointers to nodes, edges and paths previously returned become
333  * invalid.
334  */
335  void Delete();
336 
337  /**
338  * Prepare a serialized representation of the snapshot. The result
339  * is written into the stream provided in chunks of specified size.
340  * The total length of the serialized snapshot is unknown in
341  * advance, it can be roughly equal to JS heap size (that means,
342  * it can be really big - tens of megabytes).
343  *
344  * For the JSON format, heap contents are represented as an object
345  * with the following structure:
346  *
347  * {
348  * snapshot: {
349  * title: "...",
350  * uid: nnn,
351  * meta: { meta-info },
352  * node_count: nnn,
353  * edge_count: nnn
354  * },
355  * nodes: [nodes array],
356  * edges: [edges array],
357  * strings: [strings array]
358  * }
359  *
360  * Nodes reference strings, other nodes, and edges by their indexes
361  * in corresponding arrays.
362  */
363  void Serialize(OutputStream* stream, SerializationFormat format) const;
364 };
365 
366 
367 /**
368  * An interface for reporting progress and controlling long-running
369  * activities.
370  */
371 class V8_EXPORT ActivityControl { // NOLINT
372  public:
375  kAbort = 1
376  };
377  virtual ~ActivityControl() {}
378  /**
379  * Notify about current progress. The activity can be stopped by
380  * returning kAbort as the callback result.
381  */
382  virtual ControlOption ReportProgressValue(int done, int total) = 0;
383 };
384 
385 
386 /**
387  * Interface for controlling heap profiling. Instance of the
388  * profiler can be retrieved using v8::Isolate::GetHeapProfiler.
389  */
391  public:
392  /**
393  * Callback function invoked for obtaining RetainedObjectInfo for
394  * the given JavaScript wrapper object. It is prohibited to enter V8
395  * while the callback is running: only getters on the handle and
396  * GetPointerFromInternalField on the objects are allowed.
397  */
398  typedef RetainedObjectInfo* (*WrapperInfoCallback)
399  (uint16_t class_id, Handle<Value> wrapper);
400 
401  /** Returns the number of snapshots taken. */
402  int GetSnapshotCount();
403 
404  /** Returns a snapshot by index. */
405  const HeapSnapshot* GetHeapSnapshot(int index);
406 
407  /**
408  * Returns SnapshotObjectId for a heap object referenced by |value| if
409  * it has been seen by the heap profiler, kUnknownObjectId otherwise.
410  */
411  SnapshotObjectId GetObjectId(Handle<Value> value);
412 
413  /**
414  * Returns heap object with given SnapshotObjectId if the object is alive,
415  * otherwise empty handle is returned.
416  */
418 
419  /**
420  * Clears internal map from SnapshotObjectId to heap object. The new objects
421  * will not be added into it unless a heap snapshot is taken or heap object
422  * tracking is kicked off.
423  */
424  void ClearObjectIds();
425 
426  /**
427  * A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
428  * it in case heap profiler cannot find id for the object passed as
429  * parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
430  */
432 
433  /**
434  * Callback interface for retrieving user friendly names of global objects.
435  */
437  public:
438  /**
439  * Returns name to be used in the heap snapshot for given node. Returned
440  * string must stay alive until snapshot collection is completed.
441  */
442  virtual const char* GetName(Handle<Object> object) = 0;
443  protected:
444  virtual ~ObjectNameResolver() {}
445  };
446 
447  /**
448  * Takes a heap snapshot and returns it. Title may be an empty string.
449  */
451  Handle<String> title,
452  ActivityControl* control = NULL,
453  ObjectNameResolver* global_object_name_resolver = NULL);
454 
455  /**
456  * Starts tracking of heap objects population statistics. After calling
457  * this method, all heap objects relocations done by the garbage collector
458  * are being registered.
459  *
460  * |track_allocations| parameter controls whether stack trace of each
461  * allocation in the heap will be recorded and reported as part of
462  * HeapSnapshot.
463  */
464  void StartTrackingHeapObjects(bool track_allocations = false);
465 
466  /**
467  * Adds a new time interval entry to the aggregated statistics array. The
468  * time interval entry contains information on the current heap objects
469  * population size. The method also updates aggregated statistics and
470  * reports updates for all previous time intervals via the OutputStream
471  * object. Updates on each time interval are provided as a stream of the
472  * HeapStatsUpdate structure instances.
473  * The return value of the function is the last seen heap object Id.
474  *
475  * StartTrackingHeapObjects must be called before the first call to this
476  * method.
477  */
479 
480  /**
481  * Stops tracking of heap objects population statistics, cleans up all
482  * collected data. StartHeapObjectsTracking must be called again prior to
483  * calling PushHeapObjectsStats next time.
484  */
486 
487  /**
488  * Deletes all snapshots taken. All previously returned pointers to
489  * snapshots and their contents become invalid after this call.
490  */
491  void DeleteAllHeapSnapshots();
492 
493  /** Binds a callback to embedder's class ID. */
495  uint16_t class_id,
496  WrapperInfoCallback callback);
497 
498  /**
499  * Default value of persistent handle class ID. Must not be used to
500  * define a class. Can be used to reset a class of a persistent
501  * handle.
502  */
503  static const uint16_t kPersistentHandleNoClassId = 0;
504 
505  /** Returns memory used for profiler internal data and snapshots. */
507 
508  /**
509  * Sets a RetainedObjectInfo for an object group (see V8::SetObjectGroupId).
510  */
512 
513  private:
514  HeapProfiler();
515  ~HeapProfiler();
516  HeapProfiler(const HeapProfiler&);
517  HeapProfiler& operator=(const HeapProfiler&);
518 };
519 
520 
521 /**
522  * Interface for providing information about embedder's objects
523  * held by global handles. This information is reported in two ways:
524  *
525  * 1. When calling AddObjectGroup, an embedder may pass
526  * RetainedObjectInfo instance describing the group. To collect
527  * this information while taking a heap snapshot, V8 calls GC
528  * prologue and epilogue callbacks.
529  *
530  * 2. When a heap snapshot is collected, V8 additionally
531  * requests RetainedObjectInfos for persistent handles that
532  * were not previously reported via AddObjectGroup.
533  *
534  * Thus, if an embedder wants to provide information about native
535  * objects for heap snapshots, he can do it in a GC prologue
536  * handler, and / or by assigning wrapper class ids in the following way:
537  *
538  * 1. Bind a callback to class id by calling SetWrapperClassInfoProvider.
539  * 2. Call SetWrapperClassId on certain persistent handles.
540  *
541  * V8 takes ownership of RetainedObjectInfo instances passed to it and
542  * keeps them alive only during snapshot collection. Afterwards, they
543  * are freed by calling the Dispose class function.
544  */
545 class V8_EXPORT RetainedObjectInfo { // NOLINT
546  public:
547  /** Called by V8 when it no longer needs an instance. */
548  virtual void Dispose() = 0;
549 
550  /** Returns whether two instances are equivalent. */
551  virtual bool IsEquivalent(RetainedObjectInfo* other) = 0;
552 
553  /**
554  * Returns hash value for the instance. Equivalent instances
555  * must have the same hash value.
556  */
557  virtual intptr_t GetHash() = 0;
558 
559  /**
560  * Returns human-readable label. It must be a null-terminated UTF-8
561  * encoded string. V8 copies its contents during a call to GetLabel.
562  */
563  virtual const char* GetLabel() = 0;
564 
565  /**
566  * Returns human-readable group label. It must be a null-terminated UTF-8
567  * encoded string. V8 copies its contents during a call to GetGroupLabel.
568  * Heap snapshot generator will collect all the group names, create
569  * top level entries with these names and attach the objects to the
570  * corresponding top level group objects. There is a default
571  * implementation which is required because embedders don't have their
572  * own implementation yet.
573  */
574  virtual const char* GetGroupLabel() { return GetLabel(); }
575 
576  /**
577  * Returns element count in case if a global handle retains
578  * a subgraph by holding one of its nodes.
579  */
580  virtual intptr_t GetElementCount() { return -1; }
581 
582  /** Returns embedder's object size in bytes. */
583  virtual intptr_t GetSizeInBytes() { return -1; }
584 
585  protected:
587  virtual ~RetainedObjectInfo() {}
588 
589  private:
590  RetainedObjectInfo(const RetainedObjectInfo&);
591  RetainedObjectInfo& operator=(const RetainedObjectInfo&);
592 };
593 
594 
595 /**
596  * A struct for exporting HeapStats data from V8, using "push" model.
597  * See HeapProfiler::GetHeapStats.
598  */
600  HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
601  : index(index), count(count), size(size) { }
602  uint32_t index; // Index of the time interval that was changed.
603  uint32_t count; // New value of count field for the interval with this index.
604  uint32_t size; // New value of size field for the interval with this index.
605 };
606 
607 
608 } // namespace v8
609 
610 
611 #endif // V8_V8_PROFILER_H_
void DeleteAllHeapSnapshots()
const HeapGraphNode * GetFromNode() const
void StopTrackingHeapObjects()
int64_t GetSampleTimestamp(int index) const
void SetWrapperClassInfoProvider(uint16_t class_id, WrapperInfoCallback callback)
SnapshotObjectId GetObjectId(Handle< Value > value)
virtual intptr_t GetHash()=0
const HeapGraphNode * GetToNode() const
Definition: v8.h:1345
virtual ~OutputStream()
Definition: v8-profiler.h:278
SnapshotObjectId GetId() const
int64_t GetStartTime() const
virtual const char * GetName(Handle< Object > object)=0
static const int kNoColumnInfo
Definition: v8.h:1201
unsigned GetNodeId() const
Handle< String > GetScriptResourceName() const
CpuProfile * StopProfiling(Handle< String > title)
size_t GetShallowSize() const
static const int kNoLineNumberInfo
Definition: v8.h:1200
void SetSamplingInterval(int us)
const HeapGraphEdge * GetChild(int index) const
virtual ControlOption ReportProgressValue(int done, int total)=0
Handle< String > GetName() const
Handle< Value > FindObjectById(SnapshotObjectId id)
Handle< String > GetTitle() const
unsigned GetCallUid() const
int GetChildrenCount() const
virtual bool IsEquivalent(RetainedObjectInfo *other)=0
const HeapGraphNode * GetRoot() const
static const int kNoColumnNumberInfo
Definition: v8-profiler.h:69
SnapshotObjectId GetMaxSnapshotJSObjectId() const
Definition: libplatform.h:10
virtual int GetChunkSize()
Definition: v8-profiler.h:282
static const uint16_t kPersistentHandleNoClassId
Definition: v8-profiler.h:503
virtual const char * GetLabel()=0
int64_t GetEndTime() const
HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
Definition: v8-profiler.h:600
Type GetType() const
virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate *data, int count)
Definition: v8-profiler.h:294
const CpuProfileNode * GetChild(int index) const
virtual ~RetainedObjectInfo()
Definition: v8-profiler.h:587
size_t GetProfilerMemorySize()
Handle< Value > GetName() const
const HeapSnapshot * TakeHeapSnapshot(Handle< String > title, ActivityControl *control=NULL, ObjectNameResolver *global_object_name_resolver=NULL)
virtual ~ActivityControl()
Definition: v8-profiler.h:377
const CpuProfileNode * GetTopDownRoot() const
#define V8_DEPRECATED(message, declarator)
Definition: v8config.h:320
void SetRetainedObjectInfo(UniqueId id, RetainedObjectInfo *info)
int GetScriptId() const
SnapshotObjectId GetHeapStats(OutputStream *stream)
int GetSamplesCount() const
Handle< String > GetFunctionName() const
void StartProfiling(Handle< String > title, bool record_samples=false)
virtual WriteResult WriteAsciiChunk(char *data, int size)=0
const HeapGraphNode * GetNode(int index) const
virtual void Dispose()=0
uint32_t SnapshotObjectId
Definition: v8-profiler.h:16
int GetNodesCount() const
int GetChildrenCount() const
const CpuProfileNode * GetSample(int index) const
int GetColumnNumber() const
virtual intptr_t GetElementCount()
Definition: v8-profiler.h:580
unsigned GetHitCount() const
void StartTrackingHeapObjects(bool track_allocations=false)
Type GetType() const
void SetIdle(bool is_idle)
virtual void EndOfStream()=0
unsigned GetUid() const
static const int kNoLineNumberInfo
Definition: v8-profiler.h:68
virtual intptr_t GetSizeInBytes()
Definition: v8-profiler.h:583
const HeapGraphNode * GetNodeById(SnapshotObjectId id) const
Handle< String > GetTitle() const
const HeapSnapshot * GetHeapSnapshot(int index)
#define V8_EXPORT
Definition: v8.h:53
void Serialize(OutputStream *stream, SerializationFormat format) const
const char * GetBailoutReason() const
virtual const char * GetGroupLabel()
Definition: v8-profiler.h:574
int GetLineNumber() const
static const SnapshotObjectId kUnknownObjectId
Definition: v8-profiler.h:431