Line data Source code
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;
18 : struct HeapStatsUpdate;
19 :
20 : typedef uint32_t SnapshotObjectId;
21 :
22 :
23 : struct CpuProfileDeoptFrame {
24 : int script_id;
25 : size_t position;
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 :
36 0 : struct V8_EXPORT CpuProfileDeoptInfo {
37 : /** A pointer to a static string owned by v8. */
38 : const char* deopt_reason;
39 : std::vector<CpuProfileDeoptFrame> stack;
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 : // TickSample captures the information collected for each sample.
51 : struct TickSample {
52 : // Internal profiling (with --prof + tools/$OS-tick-processor) wants to
53 : // include the runtime function we're calling. Externally exposed tick
54 : // samples don't care.
55 : enum RecordCEntryFrame { kIncludeCEntryFrame, kSkipCEntryFrame };
56 :
57 : TickSample()
58 : : state(OTHER),
59 : pc(nullptr),
60 : external_callback_entry(nullptr),
61 : frames_count(0),
62 : has_external_callback(false),
63 2018921 : update_stats(true) {}
64 :
65 : /**
66 : * Initialize a tick sample from the isolate.
67 : * \param isolate The isolate.
68 : * \param state Execution state.
69 : * \param record_c_entry_frame Include or skip the runtime function.
70 : * \param update_stats Whether update the sample to the aggregated stats.
71 : * \param use_simulator_reg_state When set to true and V8 is running under a
72 : * simulator, the method will use the simulator
73 : * register state rather than the one provided
74 : * with |state| argument. Otherwise the method
75 : * will use provided register |state| as is.
76 : */
77 : void Init(Isolate* isolate, const v8::RegisterState& state,
78 : RecordCEntryFrame record_c_entry_frame, bool update_stats,
79 : bool use_simulator_reg_state = true);
80 : /**
81 : * Get a call stack sample from the isolate.
82 : * \param isolate The isolate.
83 : * \param state Register state.
84 : * \param record_c_entry_frame Include or skip the runtime function.
85 : * \param frames Caller allocated buffer to store stack frames.
86 : * \param frames_limit Maximum number of frames to capture. The buffer must
87 : * be large enough to hold the number of frames.
88 : * \param sample_info The sample info is filled up by the function
89 : * provides number of actual captured stack frames and
90 : * the current VM state.
91 : * \param use_simulator_reg_state When set to true and V8 is running under a
92 : * simulator, the method will use the simulator
93 : * register state rather than the one provided
94 : * with |state| argument. Otherwise the method
95 : * will use provided register |state| as is.
96 : * \note GetStackSample is thread and signal safe and should only be called
97 : * when the JS thread is paused or interrupted.
98 : * Otherwise the behavior is undefined.
99 : */
100 : static bool GetStackSample(Isolate* isolate, v8::RegisterState* state,
101 : RecordCEntryFrame record_c_entry_frame,
102 : void** frames, size_t frames_limit,
103 : v8::SampleInfo* sample_info,
104 : bool use_simulator_reg_state = true);
105 : StateTag state; // The state of the VM.
106 : void* pc; // Instruction pointer.
107 : union {
108 : void* tos; // Top stack value (*sp).
109 : void* external_callback_entry;
110 : };
111 : static const unsigned kMaxFramesCountLog2 = 8;
112 : static const unsigned kMaxFramesCount = (1 << kMaxFramesCountLog2) - 1;
113 : void* stack[kMaxFramesCount]; // Call stack.
114 : unsigned frames_count : kMaxFramesCountLog2; // Number of captured frames.
115 : bool has_external_callback : 1;
116 : bool update_stats : 1; // Whether the sample should update aggregated stats.
117 : };
118 :
119 : /**
120 : * CpuProfileNode represents a node in a call graph.
121 : */
122 : class V8_EXPORT CpuProfileNode {
123 : public:
124 : struct LineTick {
125 : /** The 1-based number of the source line where the function originates. */
126 : int line;
127 :
128 : /** The count of samples associated with the source line. */
129 : unsigned int hit_count;
130 : };
131 :
132 : /** Returns function name (empty string for anonymous functions.) */
133 : Local<String> GetFunctionName() const;
134 :
135 : /**
136 : * Returns function name (empty string for anonymous functions.)
137 : * The string ownership is *not* passed to the caller. It stays valid until
138 : * profile is deleted. The function is thread safe.
139 : */
140 : const char* GetFunctionNameStr() const;
141 :
142 : /** Returns id of the script where function is located. */
143 : int GetScriptId() const;
144 :
145 : /** Returns resource name for script from where the function originates. */
146 : Local<String> GetScriptResourceName() const;
147 :
148 : /**
149 : * Returns resource name for script from where the function originates.
150 : * The string ownership is *not* passed to the caller. It stays valid until
151 : * profile is deleted. The function is thread safe.
152 : */
153 : const char* GetScriptResourceNameStr() const;
154 :
155 : /**
156 : * Returns the number, 1-based, of the line where the function originates.
157 : * kNoLineNumberInfo if no line number information is available.
158 : */
159 : int GetLineNumber() const;
160 :
161 : /**
162 : * Returns 1-based number of the column where the function originates.
163 : * kNoColumnNumberInfo if no column number information is available.
164 : */
165 : int GetColumnNumber() const;
166 :
167 : /**
168 : * Returns the number of the function's source lines that collect the samples.
169 : */
170 : unsigned int GetHitLineCount() const;
171 :
172 : /** Returns the set of source lines that collect the samples.
173 : * The caller allocates buffer and responsible for releasing it.
174 : * True if all available entries are copied, otherwise false.
175 : * The function copies nothing if buffer is not large enough.
176 : */
177 : bool GetLineTicks(LineTick* entries, unsigned int length) const;
178 :
179 : /** Returns bailout reason for the function
180 : * if the optimization was disabled for it.
181 : */
182 : const char* GetBailoutReason() const;
183 :
184 : /**
185 : * Returns the count of samples where the function was currently executing.
186 : */
187 : unsigned GetHitCount() const;
188 :
189 : /** Returns function entry UID. */
190 : V8_DEPRECATE_SOON(
191 : "Use GetScriptId, GetLineNumber, and GetColumnNumber instead.",
192 : unsigned GetCallUid() const);
193 :
194 : /** Returns id of the node. The id is unique within the tree */
195 : unsigned GetNodeId() const;
196 :
197 : /** Returns child nodes count of the node. */
198 : int GetChildrenCount() const;
199 :
200 : /** Retrieves a child node by index. */
201 : const CpuProfileNode* GetChild(int index) const;
202 :
203 : /** Retrieves deopt infos for the node. */
204 : const std::vector<CpuProfileDeoptInfo>& GetDeoptInfos() const;
205 :
206 : static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
207 : static const int kNoColumnNumberInfo = Message::kNoColumnInfo;
208 : };
209 :
210 :
211 : /**
212 : * CpuProfile contains a CPU profile in a form of top-down call tree
213 : * (from main() down to functions that do all the work).
214 : */
215 : class V8_EXPORT CpuProfile {
216 : public:
217 : /** Returns CPU profile title. */
218 : Local<String> GetTitle() const;
219 :
220 : /** Returns the root node of the top down call tree. */
221 : const CpuProfileNode* GetTopDownRoot() const;
222 :
223 : /**
224 : * Returns number of samples recorded. The samples are not recorded unless
225 : * |record_samples| parameter of CpuProfiler::StartCpuProfiling is true.
226 : */
227 : int GetSamplesCount() const;
228 :
229 : /**
230 : * Returns profile node corresponding to the top frame the sample at
231 : * the given index.
232 : */
233 : const CpuProfileNode* GetSample(int index) const;
234 :
235 : /**
236 : * Returns the timestamp of the sample. The timestamp is the number of
237 : * microseconds since some unspecified starting point.
238 : * The point is equal to the starting point used by GetStartTime.
239 : */
240 : int64_t GetSampleTimestamp(int index) const;
241 :
242 : /**
243 : * Returns time when the profile recording was started (in microseconds)
244 : * since some unspecified starting point.
245 : */
246 : int64_t GetStartTime() const;
247 :
248 : /**
249 : * Returns time when the profile recording was stopped (in microseconds)
250 : * since some unspecified starting point.
251 : * The point is equal to the starting point used by GetStartTime.
252 : */
253 : int64_t GetEndTime() const;
254 :
255 : /**
256 : * Deletes the profile and removes it from CpuProfiler's list.
257 : * All pointers to nodes previously returned become invalid.
258 : */
259 : void Delete();
260 : };
261 :
262 : enum CpuProfilingMode {
263 : // In the resulting CpuProfile tree, intermediate nodes in a stack trace
264 : // (from the root to a leaf) will have line numbers that point to the start
265 : // line of the function, rather than the line of the callsite of the child.
266 : kLeafNodeLineNumbers,
267 : // In the resulting CpuProfile tree, nodes are separated based on the line
268 : // number of their callsite in their parent.
269 : kCallerLineNumbers,
270 : };
271 :
272 : /**
273 : * Interface for controlling CPU profiling. Instance of the
274 : * profiler can be created using v8::CpuProfiler::New method.
275 : */
276 : class V8_EXPORT CpuProfiler {
277 : public:
278 : /**
279 : * Creates a new CPU profiler for the |isolate|. The isolate must be
280 : * initialized. The profiler object must be disposed after use by calling
281 : * |Dispose| method.
282 : */
283 : static CpuProfiler* New(Isolate* isolate);
284 :
285 : /**
286 : * Synchronously collect current stack sample in all profilers attached to
287 : * the |isolate|. The call does not affect number of ticks recorded for
288 : * the current top node.
289 : */
290 : static void CollectSample(Isolate* isolate);
291 :
292 : /**
293 : * Disposes the CPU profiler object.
294 : */
295 : void Dispose();
296 :
297 : /**
298 : * Changes default CPU profiler sampling interval to the specified number
299 : * of microseconds. Default interval is 1000us. This method must be called
300 : * when there are no profiles being recorded.
301 : */
302 : void SetSamplingInterval(int us);
303 :
304 : /**
305 : * Starts collecting CPU profile. Title may be an empty string. It
306 : * is allowed to have several profiles being collected at
307 : * once. Attempts to start collecting several profiles with the same
308 : * title are silently ignored. While collecting a profile, functions
309 : * from all security contexts are included in it. The token-based
310 : * filtering is only performed when querying for a profile.
311 : *
312 : * |record_samples| parameter controls whether individual samples should
313 : * be recorded in addition to the aggregated tree.
314 : */
315 : void StartProfiling(Local<String> title, CpuProfilingMode mode,
316 : bool record_samples = false);
317 : /**
318 : * The same as StartProfiling above, but the CpuProfilingMode defaults to
319 : * kLeafNodeLineNumbers mode, which was the previous default behavior of the
320 : * profiler.
321 : */
322 : void StartProfiling(Local<String> title, bool record_samples = false);
323 :
324 : /**
325 : * Stops collecting CPU profile with a given title and returns it.
326 : * If the title given is empty, finishes the last profile started.
327 : */
328 : CpuProfile* StopProfiling(Local<String> title);
329 :
330 : /**
331 : * Force collection of a sample. Must be called on the VM thread.
332 : * Recording the forced sample does not contribute to the aggregated
333 : * profile statistics.
334 : */
335 : V8_DEPRECATED("Use static CollectSample(Isolate*) instead.",
336 : void CollectSample());
337 :
338 : /**
339 : * Tells the profiler whether the embedder is idle.
340 : */
341 : V8_DEPRECATED("Use Isolate::SetIdle(bool) instead.",
342 : void SetIdle(bool is_idle));
343 :
344 : /**
345 : * Generate more detailed source positions to code objects. This results in
346 : * better results when mapping profiling samples to script source.
347 : */
348 : static void UseDetailedSourcePositionsForProfiling(Isolate* isolate);
349 :
350 : private:
351 : CpuProfiler();
352 : ~CpuProfiler();
353 : CpuProfiler(const CpuProfiler&);
354 : CpuProfiler& operator=(const CpuProfiler&);
355 : };
356 :
357 :
358 : /**
359 : * HeapSnapshotEdge represents a directed connection between heap
360 : * graph nodes: from retainers to retained nodes.
361 : */
362 : class V8_EXPORT HeapGraphEdge {
363 : public:
364 : enum Type {
365 : kContextVariable = 0, // A variable from a function context.
366 : kElement = 1, // An element of an array.
367 : kProperty = 2, // A named object property.
368 : kInternal = 3, // A link that can't be accessed from JS,
369 : // thus, its name isn't a real property name
370 : // (e.g. parts of a ConsString).
371 : kHidden = 4, // A link that is needed for proper sizes
372 : // calculation, but may be hidden from user.
373 : kShortcut = 5, // A link that must not be followed during
374 : // sizes calculation.
375 : kWeak = 6 // A weak reference (ignored by the GC).
376 : };
377 :
378 : /** Returns edge type (see HeapGraphEdge::Type). */
379 : Type GetType() const;
380 :
381 : /**
382 : * Returns edge name. This can be a variable name, an element index, or
383 : * a property name.
384 : */
385 : Local<Value> GetName() const;
386 :
387 : /** Returns origin node. */
388 : const HeapGraphNode* GetFromNode() const;
389 :
390 : /** Returns destination node. */
391 : const HeapGraphNode* GetToNode() const;
392 : };
393 :
394 :
395 : /**
396 : * HeapGraphNode represents a node in a heap graph.
397 : */
398 : class V8_EXPORT HeapGraphNode {
399 : public:
400 : enum Type {
401 : kHidden = 0, // Hidden node, may be filtered when shown to user.
402 : kArray = 1, // An array of elements.
403 : kString = 2, // A string.
404 : kObject = 3, // A JS object (except for arrays and strings).
405 : kCode = 4, // Compiled code.
406 : kClosure = 5, // Function closure.
407 : kRegExp = 6, // RegExp.
408 : kHeapNumber = 7, // Number stored in the heap.
409 : kNative = 8, // Native object (not from V8 heap).
410 : kSynthetic = 9, // Synthetic object, usually used for grouping
411 : // snapshot items together.
412 : kConsString = 10, // Concatenated string. A pair of pointers to strings.
413 : kSlicedString = 11, // Sliced string. A fragment of another string.
414 : kSymbol = 12, // A Symbol (ES6).
415 : kBigInt = 13 // BigInt.
416 : };
417 :
418 : /** Returns node type (see HeapGraphNode::Type). */
419 : Type GetType() const;
420 :
421 : /**
422 : * Returns node name. Depending on node's type this can be the name
423 : * of the constructor (for objects), the name of the function (for
424 : * closures), string value, or an empty string (for compiled code).
425 : */
426 : Local<String> GetName() const;
427 :
428 : /**
429 : * Returns node id. For the same heap object, the id remains the same
430 : * across all snapshots.
431 : */
432 : SnapshotObjectId GetId() const;
433 :
434 : /** Returns node's own size, in bytes. */
435 : size_t GetShallowSize() const;
436 :
437 : /** Returns child nodes count of the node. */
438 : int GetChildrenCount() const;
439 :
440 : /** Retrieves a child by index. */
441 : const HeapGraphEdge* GetChild(int index) const;
442 : };
443 :
444 :
445 : /**
446 : * An interface for exporting data from V8, using "push" model.
447 : */
448 90 : class V8_EXPORT OutputStream { // NOLINT
449 : public:
450 : enum WriteResult {
451 : kContinue = 0,
452 : kAbort = 1
453 : };
454 90 : virtual ~OutputStream() = default;
455 : /** Notify about the end of stream. */
456 : virtual void EndOfStream() = 0;
457 : /** Get preferred output chunk size. Called only once. */
458 75 : virtual int GetChunkSize() { return 1024; }
459 : /**
460 : * Writes the next chunk of snapshot data into the stream. Writing
461 : * can be stopped by returning kAbort as function result. EndOfStream
462 : * will not be called in case writing was aborted.
463 : */
464 : virtual WriteResult WriteAsciiChunk(char* data, int size) = 0;
465 : /**
466 : * Writes the next chunk of heap stats data into the stream. Writing
467 : * can be stopped by returning kAbort as function result. EndOfStream
468 : * will not be called in case writing was aborted.
469 : */
470 0 : virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate* data, int count) {
471 0 : return kAbort;
472 : }
473 : };
474 :
475 :
476 : /**
477 : * HeapSnapshots record the state of the JS heap at some moment.
478 : */
479 : class V8_EXPORT HeapSnapshot {
480 : public:
481 : enum SerializationFormat {
482 : kJSON = 0 // See format description near 'Serialize' method.
483 : };
484 :
485 : /** Returns the root node of the heap graph. */
486 : const HeapGraphNode* GetRoot() const;
487 :
488 : /** Returns a node by its id. */
489 : const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
490 :
491 : /** Returns total nodes count in the snapshot. */
492 : int GetNodesCount() const;
493 :
494 : /** Returns a node by index. */
495 : const HeapGraphNode* GetNode(int index) const;
496 :
497 : /** Returns a max seen JS object Id. */
498 : SnapshotObjectId GetMaxSnapshotJSObjectId() const;
499 :
500 : /**
501 : * Deletes the snapshot and removes it from HeapProfiler's list.
502 : * All pointers to nodes, edges and paths previously returned become
503 : * invalid.
504 : */
505 : void Delete();
506 :
507 : /**
508 : * Prepare a serialized representation of the snapshot. The result
509 : * is written into the stream provided in chunks of specified size.
510 : * The total length of the serialized snapshot is unknown in
511 : * advance, it can be roughly equal to JS heap size (that means,
512 : * it can be really big - tens of megabytes).
513 : *
514 : * For the JSON format, heap contents are represented as an object
515 : * with the following structure:
516 : *
517 : * {
518 : * snapshot: {
519 : * title: "...",
520 : * uid: nnn,
521 : * meta: { meta-info },
522 : * node_count: nnn,
523 : * edge_count: nnn
524 : * },
525 : * nodes: [nodes array],
526 : * edges: [edges array],
527 : * strings: [strings array]
528 : * }
529 : *
530 : * Nodes reference strings, other nodes, and edges by their indexes
531 : * in corresponding arrays.
532 : */
533 : void Serialize(OutputStream* stream,
534 : SerializationFormat format = kJSON) const;
535 : };
536 :
537 :
538 : /**
539 : * An interface for reporting progress and controlling long-running
540 : * activities.
541 : */
542 15 : class V8_EXPORT ActivityControl { // NOLINT
543 : public:
544 : enum ControlOption {
545 : kContinue = 0,
546 : kAbort = 1
547 : };
548 15 : virtual ~ActivityControl() = default;
549 : /**
550 : * Notify about current progress. The activity can be stopped by
551 : * returning kAbort as the callback result.
552 : */
553 : virtual ControlOption ReportProgressValue(int done, int total) = 0;
554 : };
555 :
556 :
557 : /**
558 : * AllocationProfile is a sampled profile of allocations done by the program.
559 : * This is structured as a call-graph.
560 : */
561 64 : class V8_EXPORT AllocationProfile {
562 : public:
563 : struct Allocation {
564 : /**
565 : * Size of the sampled allocation object.
566 : */
567 : size_t size;
568 :
569 : /**
570 : * The number of objects of such size that were sampled.
571 : */
572 : unsigned int count;
573 : };
574 :
575 : /**
576 : * Represents a node in the call-graph.
577 : */
578 1896 : struct Node {
579 : /**
580 : * Name of the function. May be empty for anonymous functions or if the
581 : * script corresponding to this function has been unloaded.
582 : */
583 : Local<String> name;
584 :
585 : /**
586 : * Name of the script containing the function. May be empty if the script
587 : * name is not available, or if the script has been unloaded.
588 : */
589 : Local<String> script_name;
590 :
591 : /**
592 : * id of the script where the function is located. May be equal to
593 : * v8::UnboundScript::kNoScriptId in cases where the script doesn't exist.
594 : */
595 : int script_id;
596 :
597 : /**
598 : * Start position of the function in the script.
599 : */
600 : int start_position;
601 :
602 : /**
603 : * 1-indexed line number where the function starts. May be
604 : * kNoLineNumberInfo if no line number information is available.
605 : */
606 : int line_number;
607 :
608 : /**
609 : * 1-indexed column number where the function starts. May be
610 : * kNoColumnNumberInfo if no line number information is available.
611 : */
612 : int column_number;
613 :
614 : /**
615 : * Unique id of the node.
616 : */
617 : uint32_t node_id;
618 :
619 : /**
620 : * List of callees called from this node for which we have sampled
621 : * allocations. The lifetime of the children is scoped to the containing
622 : * AllocationProfile.
623 : */
624 : std::vector<Node*> children;
625 :
626 : /**
627 : * List of self allocations done by this node in the call-graph.
628 : */
629 : std::vector<Allocation> allocations;
630 : };
631 :
632 : /**
633 : * Represent a single sample recorded for an allocation.
634 : */
635 : struct Sample {
636 : /**
637 : * id of the node in the profile tree.
638 : */
639 : uint32_t node_id;
640 :
641 : /**
642 : * Size of the sampled allocation object.
643 : */
644 : size_t size;
645 :
646 : /**
647 : * The number of objects of such size that were sampled.
648 : */
649 : unsigned int count;
650 :
651 : /**
652 : * Unique time-ordered id of the allocation sample. Can be used to track
653 : * what samples were added or removed between two snapshots.
654 : */
655 : uint64_t sample_id;
656 : };
657 :
658 : /**
659 : * Returns the root node of the call-graph. The root node corresponds to an
660 : * empty JS call-stack. The lifetime of the returned Node* is scoped to the
661 : * containing AllocationProfile.
662 : */
663 : virtual Node* GetRootNode() = 0;
664 : virtual const std::vector<Sample>& GetSamples() = 0;
665 :
666 64 : virtual ~AllocationProfile() = default;
667 :
668 : static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
669 : static const int kNoColumnNumberInfo = Message::kNoColumnInfo;
670 : };
671 :
672 : /**
673 : * An object graph consisting of embedder objects and V8 objects.
674 : * Edges of the graph are strong references between the objects.
675 : * The embedder can build this graph during heap snapshot generation
676 : * to include the embedder objects in the heap snapshot.
677 : * Usage:
678 : * 1) Define derived class of EmbedderGraph::Node for embedder objects.
679 : * 2) Set the build embedder graph callback on the heap profiler using
680 : * HeapProfiler::AddBuildEmbedderGraphCallback.
681 : * 3) In the callback use graph->AddEdge(node1, node2) to add an edge from
682 : * node1 to node2.
683 : * 4) To represent references from/to V8 object, construct V8 nodes using
684 : * graph->V8Node(value).
685 : */
686 35 : class V8_EXPORT EmbedderGraph {
687 : public:
688 : class Node {
689 : public:
690 140 : Node() = default;
691 140 : virtual ~Node() = default;
692 : virtual const char* Name() = 0;
693 : virtual size_t SizeInBytes() = 0;
694 : /**
695 : * The corresponding V8 wrapper node if not null.
696 : * During heap snapshot generation the embedder node and the V8 wrapper
697 : * node will be merged into one node to simplify retaining paths.
698 : */
699 185 : virtual Node* WrapperNode() { return nullptr; }
700 125 : virtual bool IsRootNode() { return false; }
701 : /** Must return true for non-V8 nodes. */
702 170 : virtual bool IsEmbedderNode() { return true; }
703 : /**
704 : * Optional name prefix. It is used in Chrome for tagging detached nodes.
705 : */
706 85 : virtual const char* NamePrefix() { return nullptr; }
707 :
708 : private:
709 : Node(const Node&) = delete;
710 : Node& operator=(const Node&) = delete;
711 : };
712 :
713 : /**
714 : * Returns a node corresponding to the given V8 value. Ownership is not
715 : * transferred. The result pointer is valid while the graph is alive.
716 : */
717 : virtual Node* V8Node(const v8::Local<v8::Value>& value) = 0;
718 :
719 : /**
720 : * Adds the given node to the graph and takes ownership of the node.
721 : * Returns a raw pointer to the node that is valid while the graph is alive.
722 : */
723 : virtual Node* AddNode(std::unique_ptr<Node> node) = 0;
724 :
725 : /**
726 : * Adds an edge that represents a strong reference from the given
727 : * node |from| to the given node |to|. The nodes must be added to the graph
728 : * before calling this function.
729 : *
730 : * If name is nullptr, the edge will have auto-increment indexes, otherwise
731 : * it will be named accordingly.
732 : */
733 : virtual void AddEdge(Node* from, Node* to, const char* name = nullptr) = 0;
734 :
735 35 : virtual ~EmbedderGraph() = default;
736 : };
737 :
738 : /**
739 : * Interface for controlling heap profiling. Instance of the
740 : * profiler can be retrieved using v8::Isolate::GetHeapProfiler.
741 : */
742 : class V8_EXPORT HeapProfiler {
743 : public:
744 : enum SamplingFlags {
745 : kSamplingNoFlags = 0,
746 : kSamplingForceGC = 1 << 0,
747 : };
748 :
749 : /**
750 : * Callback function invoked during heap snapshot generation to retrieve
751 : * the embedder object graph. The callback should use graph->AddEdge(..) to
752 : * add references between the objects.
753 : * The callback must not trigger garbage collection in V8.
754 : */
755 : typedef void (*BuildEmbedderGraphCallback)(v8::Isolate* isolate,
756 : v8::EmbedderGraph* graph,
757 : void* data);
758 :
759 : /** TODO(addaleax): Remove */
760 : typedef void (*LegacyBuildEmbedderGraphCallback)(v8::Isolate* isolate,
761 : v8::EmbedderGraph* graph);
762 :
763 : /** Returns the number of snapshots taken. */
764 : int GetSnapshotCount();
765 :
766 : /** Returns a snapshot by index. */
767 : const HeapSnapshot* GetHeapSnapshot(int index);
768 :
769 : /**
770 : * Returns SnapshotObjectId for a heap object referenced by |value| if
771 : * it has been seen by the heap profiler, kUnknownObjectId otherwise.
772 : */
773 : SnapshotObjectId GetObjectId(Local<Value> value);
774 :
775 : /**
776 : * Returns heap object with given SnapshotObjectId if the object is alive,
777 : * otherwise empty handle is returned.
778 : */
779 : Local<Value> FindObjectById(SnapshotObjectId id);
780 :
781 : /**
782 : * Clears internal map from SnapshotObjectId to heap object. The new objects
783 : * will not be added into it unless a heap snapshot is taken or heap object
784 : * tracking is kicked off.
785 : */
786 : void ClearObjectIds();
787 :
788 : /**
789 : * A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
790 : * it in case heap profiler cannot find id for the object passed as
791 : * parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
792 : */
793 : static const SnapshotObjectId kUnknownObjectId = 0;
794 :
795 : /**
796 : * Callback interface for retrieving user friendly names of global objects.
797 : */
798 25 : class ObjectNameResolver {
799 : public:
800 : /**
801 : * Returns name to be used in the heap snapshot for given node. Returned
802 : * string must stay alive until snapshot collection is completed.
803 : */
804 : virtual const char* GetName(Local<Object> object) = 0;
805 :
806 : protected:
807 30 : virtual ~ObjectNameResolver() = default;
808 : };
809 :
810 : /**
811 : * Takes a heap snapshot and returns it.
812 : */
813 : const HeapSnapshot* TakeHeapSnapshot(
814 : ActivityControl* control = nullptr,
815 : ObjectNameResolver* global_object_name_resolver = nullptr);
816 :
817 : /**
818 : * Starts tracking of heap objects population statistics. After calling
819 : * this method, all heap objects relocations done by the garbage collector
820 : * are being registered.
821 : *
822 : * |track_allocations| parameter controls whether stack trace of each
823 : * allocation in the heap will be recorded and reported as part of
824 : * HeapSnapshot.
825 : */
826 : void StartTrackingHeapObjects(bool track_allocations = false);
827 :
828 : /**
829 : * Adds a new time interval entry to the aggregated statistics array. The
830 : * time interval entry contains information on the current heap objects
831 : * population size. The method also updates aggregated statistics and
832 : * reports updates for all previous time intervals via the OutputStream
833 : * object. Updates on each time interval are provided as a stream of the
834 : * HeapStatsUpdate structure instances.
835 : * If |timestamp_us| is supplied, timestamp of the new entry will be written
836 : * into it. The return value of the function is the last seen heap object Id.
837 : *
838 : * StartTrackingHeapObjects must be called before the first call to this
839 : * method.
840 : */
841 : SnapshotObjectId GetHeapStats(OutputStream* stream,
842 : int64_t* timestamp_us = nullptr);
843 :
844 : /**
845 : * Stops tracking of heap objects population statistics, cleans up all
846 : * collected data. StartHeapObjectsTracking must be called again prior to
847 : * calling GetHeapStats next time.
848 : */
849 : void StopTrackingHeapObjects();
850 :
851 : /**
852 : * Starts gathering a sampling heap profile. A sampling heap profile is
853 : * similar to tcmalloc's heap profiler and Go's mprof. It samples object
854 : * allocations and builds an online 'sampling' heap profile. At any point in
855 : * time, this profile is expected to be a representative sample of objects
856 : * currently live in the system. Each sampled allocation includes the stack
857 : * trace at the time of allocation, which makes this really useful for memory
858 : * leak detection.
859 : *
860 : * This mechanism is intended to be cheap enough that it can be used in
861 : * production with minimal performance overhead.
862 : *
863 : * Allocations are sampled using a randomized Poisson process. On average, one
864 : * allocation will be sampled every |sample_interval| bytes allocated. The
865 : * |stack_depth| parameter controls the maximum number of stack frames to be
866 : * captured on each allocation.
867 : *
868 : * NOTE: This is a proof-of-concept at this point. Right now we only sample
869 : * newspace allocations. Support for paged space allocation (e.g. pre-tenured
870 : * objects, large objects, code objects, etc.) and native allocations
871 : * doesn't exist yet, but is anticipated in the future.
872 : *
873 : * Objects allocated before the sampling is started will not be included in
874 : * the profile.
875 : *
876 : * Returns false if a sampling heap profiler is already running.
877 : */
878 : bool StartSamplingHeapProfiler(uint64_t sample_interval = 512 * 1024,
879 : int stack_depth = 16,
880 : SamplingFlags flags = kSamplingNoFlags);
881 :
882 : /**
883 : * Stops the sampling heap profile and discards the current profile.
884 : */
885 : void StopSamplingHeapProfiler();
886 :
887 : /**
888 : * Returns the sampled profile of allocations allocated (and still live) since
889 : * StartSamplingHeapProfiler was called. The ownership of the pointer is
890 : * transferred to the caller. Returns nullptr if sampling heap profiler is not
891 : * active.
892 : */
893 : AllocationProfile* GetAllocationProfile();
894 :
895 : /**
896 : * Deletes all snapshots taken. All previously returned pointers to
897 : * snapshots and their contents become invalid after this call.
898 : */
899 : void DeleteAllHeapSnapshots();
900 :
901 : V8_DEPRECATED(
902 : "Use AddBuildEmbedderGraphCallback to provide info about embedder nodes",
903 : void SetBuildEmbedderGraphCallback(
904 : LegacyBuildEmbedderGraphCallback callback));
905 : void AddBuildEmbedderGraphCallback(BuildEmbedderGraphCallback callback,
906 : void* data);
907 : void RemoveBuildEmbedderGraphCallback(BuildEmbedderGraphCallback callback,
908 : void* data);
909 :
910 : /**
911 : * Default value of persistent handle class ID. Must not be used to
912 : * define a class. Can be used to reset a class of a persistent
913 : * handle.
914 : */
915 : static const uint16_t kPersistentHandleNoClassId = 0;
916 :
917 : private:
918 : HeapProfiler();
919 : ~HeapProfiler();
920 : HeapProfiler(const HeapProfiler&);
921 : HeapProfiler& operator=(const HeapProfiler&);
922 : };
923 :
924 : /**
925 : * A struct for exporting HeapStats data from V8, using "push" model.
926 : * See HeapProfiler::GetHeapStats.
927 : */
928 : struct HeapStatsUpdate {
929 : HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
930 50 : : index(index), count(count), size(size) { }
931 : uint32_t index; // Index of the time interval that was changed.
932 : uint32_t count; // New value of count field for the interval with this index.
933 : uint32_t size; // New value of size field for the interval with this index.
934 : };
935 :
936 : #define CODE_EVENTS_LIST(V) \
937 : V(Builtin) \
938 : V(Callback) \
939 : V(Eval) \
940 : V(Function) \
941 : V(InterpretedFunction) \
942 : V(Handler) \
943 : V(BytecodeHandler) \
944 : V(LazyCompile) \
945 : V(RegExp) \
946 : V(Script) \
947 : V(Stub)
948 :
949 : /**
950 : * Note that this enum may be extended in the future. Please include a default
951 : * case if this enum is used in a switch statement.
952 : */
953 : enum CodeEventType {
954 : kUnknownType = 0
955 : #define V(Name) , k##Name##Type
956 : CODE_EVENTS_LIST(V)
957 : #undef V
958 : };
959 :
960 : /**
961 : * Representation of a code creation event
962 : */
963 : class V8_EXPORT CodeEvent {
964 : public:
965 : uintptr_t GetCodeStartAddress();
966 : size_t GetCodeSize();
967 : Local<String> GetFunctionName();
968 : Local<String> GetScriptName();
969 : int GetScriptLine();
970 : int GetScriptColumn();
971 : /**
972 : * NOTE (mmarchini): We can't allocate objects in the heap when we collect
973 : * existing code, and both the code type and the comment are not stored in the
974 : * heap, so we return those as const char*.
975 : */
976 : CodeEventType GetCodeType();
977 : const char* GetComment();
978 :
979 : static const char* GetCodeEventTypeName(CodeEventType code_event_type);
980 : };
981 :
982 : /**
983 : * Interface to listen to code creation events.
984 : */
985 : class V8_EXPORT CodeEventHandler {
986 : public:
987 : /**
988 : * Creates a new listener for the |isolate|. The isolate must be initialized.
989 : * The listener object must be disposed after use by calling |Dispose| method.
990 : * Multiple listeners can be created for the same isolate.
991 : */
992 : explicit CodeEventHandler(Isolate* isolate);
993 : virtual ~CodeEventHandler();
994 :
995 : virtual void Handle(CodeEvent* code_event) = 0;
996 :
997 : void Enable();
998 : void Disable();
999 :
1000 : private:
1001 : CodeEventHandler();
1002 : CodeEventHandler(const CodeEventHandler&);
1003 : CodeEventHandler& operator=(const CodeEventHandler&);
1004 : void* internal_listener_;
1005 : };
1006 :
1007 : } // namespace v8
1008 :
1009 :
1010 : #endif // V8_V8_PROFILER_H_
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