LCOV - code coverage report
Current view: top level - include - v8-profiler.h (source / functions) Hit Total Coverage
Test: app.info Lines: 21 23 91.3 %
Date: 2019-03-21 Functions: 7 8 87.5 %

          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          24 : 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     2223307 :         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             :    * Return true if the script from where the function originates is flagged as
     157             :    * being shared cross-origin.
     158             :    */
     159             :   bool IsScriptSharedCrossOrigin() const;
     160             : 
     161             :   /**
     162             :    * Returns the number, 1-based, of the line where the function originates.
     163             :    * kNoLineNumberInfo if no line number information is available.
     164             :    */
     165             :   int GetLineNumber() const;
     166             : 
     167             :   /**
     168             :    * Returns 1-based number of the column where the function originates.
     169             :    * kNoColumnNumberInfo if no column number information is available.
     170             :    */
     171             :   int GetColumnNumber() const;
     172             : 
     173             :   /**
     174             :    * Returns the number of the function's source lines that collect the samples.
     175             :    */
     176             :   unsigned int GetHitLineCount() const;
     177             : 
     178             :   /** Returns the set of source lines that collect the samples.
     179             :    *  The caller allocates buffer and responsible for releasing it.
     180             :    *  True if all available entries are copied, otherwise false.
     181             :    *  The function copies nothing if buffer is not large enough.
     182             :    */
     183             :   bool GetLineTicks(LineTick* entries, unsigned int length) const;
     184             : 
     185             :   /** Returns bailout reason for the function
     186             :     * if the optimization was disabled for it.
     187             :     */
     188             :   const char* GetBailoutReason() const;
     189             : 
     190             :   /**
     191             :     * Returns the count of samples where the function was currently executing.
     192             :     */
     193             :   unsigned GetHitCount() const;
     194             : 
     195             :   /** Returns function entry UID. */
     196             :   V8_DEPRECATE_SOON(
     197             :       "Use GetScriptId, GetLineNumber, and GetColumnNumber instead.",
     198             :       unsigned GetCallUid() const);
     199             : 
     200             :   /** Returns id of the node. The id is unique within the tree */
     201             :   unsigned GetNodeId() const;
     202             : 
     203             :   /** Returns child nodes count of the node. */
     204             :   int GetChildrenCount() const;
     205             : 
     206             :   /** Retrieves a child node by index. */
     207             :   const CpuProfileNode* GetChild(int index) const;
     208             : 
     209             :   /** Retrieves the ancestor node, or null if the root. */
     210             :   const CpuProfileNode* GetParent() const;
     211             : 
     212             :   /** Retrieves deopt infos for the node. */
     213             :   const std::vector<CpuProfileDeoptInfo>& GetDeoptInfos() const;
     214             : 
     215             :   static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
     216             :   static const int kNoColumnNumberInfo = Message::kNoColumnInfo;
     217             : };
     218             : 
     219             : 
     220             : /**
     221             :  * CpuProfile contains a CPU profile in a form of top-down call tree
     222             :  * (from main() down to functions that do all the work).
     223             :  */
     224             : class V8_EXPORT CpuProfile {
     225             :  public:
     226             :   /** Returns CPU profile title. */
     227             :   Local<String> GetTitle() const;
     228             : 
     229             :   /** Returns the root node of the top down call tree. */
     230             :   const CpuProfileNode* GetTopDownRoot() const;
     231             : 
     232             :   /**
     233             :    * Returns number of samples recorded. The samples are not recorded unless
     234             :    * |record_samples| parameter of CpuProfiler::StartCpuProfiling is true.
     235             :    */
     236             :   int GetSamplesCount() const;
     237             : 
     238             :   /**
     239             :    * Returns profile node corresponding to the top frame the sample at
     240             :    * the given index.
     241             :    */
     242             :   const CpuProfileNode* GetSample(int index) const;
     243             : 
     244             :   /**
     245             :    * Returns the timestamp of the sample. The timestamp is the number of
     246             :    * microseconds since some unspecified starting point.
     247             :    * The point is equal to the starting point used by GetStartTime.
     248             :    */
     249             :   int64_t GetSampleTimestamp(int index) const;
     250             : 
     251             :   /**
     252             :    * Returns time when the profile recording was started (in microseconds)
     253             :    * since some unspecified starting point.
     254             :    */
     255             :   int64_t GetStartTime() const;
     256             : 
     257             :   /**
     258             :    * Returns time when the profile recording was stopped (in microseconds)
     259             :    * since some unspecified starting point.
     260             :    * The point is equal to the starting point used by GetStartTime.
     261             :    */
     262             :   int64_t GetEndTime() const;
     263             : 
     264             :   /**
     265             :    * Deletes the profile and removes it from CpuProfiler's list.
     266             :    * All pointers to nodes previously returned become invalid.
     267             :    */
     268             :   void Delete();
     269             : };
     270             : 
     271             : enum CpuProfilingMode {
     272             :   // In the resulting CpuProfile tree, intermediate nodes in a stack trace
     273             :   // (from the root to a leaf) will have line numbers that point to the start
     274             :   // line of the function, rather than the line of the callsite of the child.
     275             :   kLeafNodeLineNumbers,
     276             :   // In the resulting CpuProfile tree, nodes are separated based on the line
     277             :   // number of their callsite in their parent.
     278             :   kCallerLineNumbers,
     279             : };
     280             : 
     281             : /**
     282             :  * Interface for controlling CPU profiling. Instance of the
     283             :  * profiler can be created using v8::CpuProfiler::New method.
     284             :  */
     285             : class V8_EXPORT CpuProfiler {
     286             :  public:
     287             :   /**
     288             :    * Creates a new CPU profiler for the |isolate|. The isolate must be
     289             :    * initialized. The profiler object must be disposed after use by calling
     290             :    * |Dispose| method.
     291             :    */
     292             :   static CpuProfiler* New(Isolate* isolate);
     293             : 
     294             :   /**
     295             :    * Synchronously collect current stack sample in all profilers attached to
     296             :    * the |isolate|. The call does not affect number of ticks recorded for
     297             :    * the current top node.
     298             :    */
     299             :   static void CollectSample(Isolate* isolate);
     300             : 
     301             :   /**
     302             :    * Disposes the CPU profiler object.
     303             :    */
     304             :   void Dispose();
     305             : 
     306             :   /**
     307             :    * Changes default CPU profiler sampling interval to the specified number
     308             :    * of microseconds. Default interval is 1000us. This method must be called
     309             :    * when there are no profiles being recorded.
     310             :    */
     311             :   void SetSamplingInterval(int us);
     312             : 
     313             :   /**
     314             :    * Starts collecting CPU profile. Title may be an empty string. It
     315             :    * is allowed to have several profiles being collected at
     316             :    * once. Attempts to start collecting several profiles with the same
     317             :    * title are silently ignored. While collecting a profile, functions
     318             :    * from all security contexts are included in it. The token-based
     319             :    * filtering is only performed when querying for a profile.
     320             :    *
     321             :    * |record_samples| parameter controls whether individual samples should
     322             :    * be recorded in addition to the aggregated tree.
     323             :    */
     324             :   void StartProfiling(Local<String> title, CpuProfilingMode mode,
     325             :                       bool record_samples = false);
     326             :   /**
     327             :    * The same as StartProfiling above, but the CpuProfilingMode defaults to
     328             :    * kLeafNodeLineNumbers mode, which was the previous default behavior of the
     329             :    * profiler.
     330             :    */
     331             :   void StartProfiling(Local<String> title, bool record_samples = false);
     332             : 
     333             :   /**
     334             :    * Stops collecting CPU profile with a given title and returns it.
     335             :    * If the title given is empty, finishes the last profile started.
     336             :    */
     337             :   CpuProfile* StopProfiling(Local<String> title);
     338             : 
     339             :   /**
     340             :    * Force collection of a sample. Must be called on the VM thread.
     341             :    * Recording the forced sample does not contribute to the aggregated
     342             :    * profile statistics.
     343             :    */
     344             :   V8_DEPRECATED("Use static CollectSample(Isolate*) instead.",
     345             :                 void CollectSample());
     346             : 
     347             :   /**
     348             :    * Tells the profiler whether the embedder is idle.
     349             :    */
     350             :   V8_DEPRECATED("Use Isolate::SetIdle(bool) instead.",
     351             :                 void SetIdle(bool is_idle));
     352             : 
     353             :   /**
     354             :    * Generate more detailed source positions to code objects. This results in
     355             :    * better results when mapping profiling samples to script source.
     356             :    */
     357             :   static void UseDetailedSourcePositionsForProfiling(Isolate* isolate);
     358             : 
     359             :  private:
     360             :   CpuProfiler();
     361             :   ~CpuProfiler();
     362             :   CpuProfiler(const CpuProfiler&);
     363             :   CpuProfiler& operator=(const CpuProfiler&);
     364             : };
     365             : 
     366             : 
     367             : /**
     368             :  * HeapSnapshotEdge represents a directed connection between heap
     369             :  * graph nodes: from retainers to retained nodes.
     370             :  */
     371             : class V8_EXPORT HeapGraphEdge {
     372             :  public:
     373             :   enum Type {
     374             :     kContextVariable = 0,  // A variable from a function context.
     375             :     kElement = 1,          // An element of an array.
     376             :     kProperty = 2,         // A named object property.
     377             :     kInternal = 3,         // A link that can't be accessed from JS,
     378             :                            // thus, its name isn't a real property name
     379             :                            // (e.g. parts of a ConsString).
     380             :     kHidden = 4,           // A link that is needed for proper sizes
     381             :                            // calculation, but may be hidden from user.
     382             :     kShortcut = 5,         // A link that must not be followed during
     383             :                            // sizes calculation.
     384             :     kWeak = 6              // A weak reference (ignored by the GC).
     385             :   };
     386             : 
     387             :   /** Returns edge type (see HeapGraphEdge::Type). */
     388             :   Type GetType() const;
     389             : 
     390             :   /**
     391             :    * Returns edge name. This can be a variable name, an element index, or
     392             :    * a property name.
     393             :    */
     394             :   Local<Value> GetName() const;
     395             : 
     396             :   /** Returns origin node. */
     397             :   const HeapGraphNode* GetFromNode() const;
     398             : 
     399             :   /** Returns destination node. */
     400             :   const HeapGraphNode* GetToNode() const;
     401             : };
     402             : 
     403             : 
     404             : /**
     405             :  * HeapGraphNode represents a node in a heap graph.
     406             :  */
     407             : class V8_EXPORT HeapGraphNode {
     408             :  public:
     409             :   enum Type {
     410             :     kHidden = 0,         // Hidden node, may be filtered when shown to user.
     411             :     kArray = 1,          // An array of elements.
     412             :     kString = 2,         // A string.
     413             :     kObject = 3,         // A JS object (except for arrays and strings).
     414             :     kCode = 4,           // Compiled code.
     415             :     kClosure = 5,        // Function closure.
     416             :     kRegExp = 6,         // RegExp.
     417             :     kHeapNumber = 7,     // Number stored in the heap.
     418             :     kNative = 8,         // Native object (not from V8 heap).
     419             :     kSynthetic = 9,      // Synthetic object, usually used for grouping
     420             :                          // snapshot items together.
     421             :     kConsString = 10,    // Concatenated string. A pair of pointers to strings.
     422             :     kSlicedString = 11,  // Sliced string. A fragment of another string.
     423             :     kSymbol = 12,        // A Symbol (ES6).
     424             :     kBigInt = 13         // BigInt.
     425             :   };
     426             : 
     427             :   /** Returns node type (see HeapGraphNode::Type). */
     428             :   Type GetType() const;
     429             : 
     430             :   /**
     431             :    * Returns node name. Depending on node's type this can be the name
     432             :    * of the constructor (for objects), the name of the function (for
     433             :    * closures), string value, or an empty string (for compiled code).
     434             :    */
     435             :   Local<String> GetName() const;
     436             : 
     437             :   /**
     438             :    * Returns node id. For the same heap object, the id remains the same
     439             :    * across all snapshots.
     440             :    */
     441             :   SnapshotObjectId GetId() const;
     442             : 
     443             :   /** Returns node's own size, in bytes. */
     444             :   size_t GetShallowSize() const;
     445             : 
     446             :   /** Returns child nodes count of the node. */
     447             :   int GetChildrenCount() const;
     448             : 
     449             :   /** Retrieves a child by index. */
     450             :   const HeapGraphEdge* GetChild(int index) const;
     451             : };
     452             : 
     453             : 
     454             : /**
     455             :  * An interface for exporting data from V8, using "push" model.
     456             :  */
     457          90 : class V8_EXPORT OutputStream {  // NOLINT
     458             :  public:
     459             :   enum WriteResult {
     460             :     kContinue = 0,
     461             :     kAbort = 1
     462             :   };
     463          90 :   virtual ~OutputStream() = default;
     464             :   /** Notify about the end of stream. */
     465             :   virtual void EndOfStream() = 0;
     466             :   /** Get preferred output chunk size. Called only once. */
     467          75 :   virtual int GetChunkSize() { return 1024; }
     468             :   /**
     469             :    * Writes the next chunk of snapshot data into the stream. Writing
     470             :    * can be stopped by returning kAbort as function result. EndOfStream
     471             :    * will not be called in case writing was aborted.
     472             :    */
     473             :   virtual WriteResult WriteAsciiChunk(char* data, int size) = 0;
     474             :   /**
     475             :    * Writes the next chunk of heap stats data into the stream. Writing
     476             :    * can be stopped by returning kAbort as function result. EndOfStream
     477             :    * will not be called in case writing was aborted.
     478             :    */
     479           0 :   virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate* data, int count) {
     480           0 :     return kAbort;
     481             :   }
     482             : };
     483             : 
     484             : 
     485             : /**
     486             :  * HeapSnapshots record the state of the JS heap at some moment.
     487             :  */
     488             : class V8_EXPORT HeapSnapshot {
     489             :  public:
     490             :   enum SerializationFormat {
     491             :     kJSON = 0  // See format description near 'Serialize' method.
     492             :   };
     493             : 
     494             :   /** Returns the root node of the heap graph. */
     495             :   const HeapGraphNode* GetRoot() const;
     496             : 
     497             :   /** Returns a node by its id. */
     498             :   const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
     499             : 
     500             :   /** Returns total nodes count in the snapshot. */
     501             :   int GetNodesCount() const;
     502             : 
     503             :   /** Returns a node by index. */
     504             :   const HeapGraphNode* GetNode(int index) const;
     505             : 
     506             :   /** Returns a max seen JS object Id. */
     507             :   SnapshotObjectId GetMaxSnapshotJSObjectId() const;
     508             : 
     509             :   /**
     510             :    * Deletes the snapshot and removes it from HeapProfiler's list.
     511             :    * All pointers to nodes, edges and paths previously returned become
     512             :    * invalid.
     513             :    */
     514             :   void Delete();
     515             : 
     516             :   /**
     517             :    * Prepare a serialized representation of the snapshot. The result
     518             :    * is written into the stream provided in chunks of specified size.
     519             :    * The total length of the serialized snapshot is unknown in
     520             :    * advance, it can be roughly equal to JS heap size (that means,
     521             :    * it can be really big - tens of megabytes).
     522             :    *
     523             :    * For the JSON format, heap contents are represented as an object
     524             :    * with the following structure:
     525             :    *
     526             :    *  {
     527             :    *    snapshot: {
     528             :    *      title: "...",
     529             :    *      uid: nnn,
     530             :    *      meta: { meta-info },
     531             :    *      node_count: nnn,
     532             :    *      edge_count: nnn
     533             :    *    },
     534             :    *    nodes: [nodes array],
     535             :    *    edges: [edges array],
     536             :    *    strings: [strings array]
     537             :    *  }
     538             :    *
     539             :    * Nodes reference strings, other nodes, and edges by their indexes
     540             :    * in corresponding arrays.
     541             :    */
     542             :   void Serialize(OutputStream* stream,
     543             :                  SerializationFormat format = kJSON) const;
     544             : };
     545             : 
     546             : 
     547             : /**
     548             :  * An interface for reporting progress and controlling long-running
     549             :  * activities.
     550             :  */
     551          15 : class V8_EXPORT ActivityControl {  // NOLINT
     552             :  public:
     553             :   enum ControlOption {
     554             :     kContinue = 0,
     555             :     kAbort = 1
     556             :   };
     557          15 :   virtual ~ActivityControl() = default;
     558             :   /**
     559             :    * Notify about current progress. The activity can be stopped by
     560             :    * returning kAbort as the callback result.
     561             :    */
     562             :   virtual ControlOption ReportProgressValue(int done, int total) = 0;
     563             : };
     564             : 
     565             : 
     566             : /**
     567             :  * AllocationProfile is a sampled profile of allocations done by the program.
     568             :  * This is structured as a call-graph.
     569             :  */
     570          64 : class V8_EXPORT AllocationProfile {
     571             :  public:
     572             :   struct Allocation {
     573             :     /**
     574             :      * Size of the sampled allocation object.
     575             :      */
     576             :     size_t size;
     577             : 
     578             :     /**
     579             :      * The number of objects of such size that were sampled.
     580             :      */
     581             :     unsigned int count;
     582             :   };
     583             : 
     584             :   /**
     585             :    * Represents a node in the call-graph.
     586             :    */
     587        1842 :   struct Node {
     588             :     /**
     589             :      * Name of the function. May be empty for anonymous functions or if the
     590             :      * script corresponding to this function has been unloaded.
     591             :      */
     592             :     Local<String> name;
     593             : 
     594             :     /**
     595             :      * Name of the script containing the function. May be empty if the script
     596             :      * name is not available, or if the script has been unloaded.
     597             :      */
     598             :     Local<String> script_name;
     599             : 
     600             :     /**
     601             :      * id of the script where the function is located. May be equal to
     602             :      * v8::UnboundScript::kNoScriptId in cases where the script doesn't exist.
     603             :      */
     604             :     int script_id;
     605             : 
     606             :     /**
     607             :      * Start position of the function in the script.
     608             :      */
     609             :     int start_position;
     610             : 
     611             :     /**
     612             :      * 1-indexed line number where the function starts. May be
     613             :      * kNoLineNumberInfo if no line number information is available.
     614             :      */
     615             :     int line_number;
     616             : 
     617             :     /**
     618             :      * 1-indexed column number where the function starts. May be
     619             :      * kNoColumnNumberInfo if no line number information is available.
     620             :      */
     621             :     int column_number;
     622             : 
     623             :     /**
     624             :      * Unique id of the node.
     625             :      */
     626             :     uint32_t node_id;
     627             : 
     628             :     /**
     629             :      * List of callees called from this node for which we have sampled
     630             :      * allocations. The lifetime of the children is scoped to the containing
     631             :      * AllocationProfile.
     632             :      */
     633             :     std::vector<Node*> children;
     634             : 
     635             :     /**
     636             :      * List of self allocations done by this node in the call-graph.
     637             :      */
     638             :     std::vector<Allocation> allocations;
     639             :   };
     640             : 
     641             :   /**
     642             :    * Represent a single sample recorded for an allocation.
     643             :    */
     644             :   struct Sample {
     645             :     /**
     646             :      * id of the node in the profile tree.
     647             :      */
     648             :     uint32_t node_id;
     649             : 
     650             :     /**
     651             :      * Size of the sampled allocation object.
     652             :      */
     653             :     size_t size;
     654             : 
     655             :     /**
     656             :      * The number of objects of such size that were sampled.
     657             :      */
     658             :     unsigned int count;
     659             : 
     660             :     /**
     661             :      * Unique time-ordered id of the allocation sample. Can be used to track
     662             :      * what samples were added or removed between two snapshots.
     663             :      */
     664             :     uint64_t sample_id;
     665             :   };
     666             : 
     667             :   /**
     668             :    * Returns the root node of the call-graph. The root node corresponds to an
     669             :    * empty JS call-stack. The lifetime of the returned Node* is scoped to the
     670             :    * containing AllocationProfile.
     671             :    */
     672             :   virtual Node* GetRootNode() = 0;
     673             :   virtual const std::vector<Sample>& GetSamples() = 0;
     674             : 
     675          64 :   virtual ~AllocationProfile() = default;
     676             : 
     677             :   static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
     678             :   static const int kNoColumnNumberInfo = Message::kNoColumnInfo;
     679             : };
     680             : 
     681             : /**
     682             :  * An object graph consisting of embedder objects and V8 objects.
     683             :  * Edges of the graph are strong references between the objects.
     684             :  * The embedder can build this graph during heap snapshot generation
     685             :  * to include the embedder objects in the heap snapshot.
     686             :  * Usage:
     687             :  * 1) Define derived class of EmbedderGraph::Node for embedder objects.
     688             :  * 2) Set the build embedder graph callback on the heap profiler using
     689             :  *    HeapProfiler::AddBuildEmbedderGraphCallback.
     690             :  * 3) In the callback use graph->AddEdge(node1, node2) to add an edge from
     691             :  *    node1 to node2.
     692             :  * 4) To represent references from/to V8 object, construct V8 nodes using
     693             :  *    graph->V8Node(value).
     694             :  */
     695          35 : class V8_EXPORT EmbedderGraph {
     696             :  public:
     697             :   class Node {
     698             :    public:
     699         140 :     Node() = default;
     700         140 :     virtual ~Node() = default;
     701             :     virtual const char* Name() = 0;
     702             :     virtual size_t SizeInBytes() = 0;
     703             :     /**
     704             :      * The corresponding V8 wrapper node if not null.
     705             :      * During heap snapshot generation the embedder node and the V8 wrapper
     706             :      * node will be merged into one node to simplify retaining paths.
     707             :      */
     708         185 :     virtual Node* WrapperNode() { return nullptr; }
     709         200 :     virtual bool IsRootNode() { return false; }
     710             :     /** Must return true for non-V8 nodes. */
     711         170 :     virtual bool IsEmbedderNode() { return true; }
     712             :     /**
     713             :      * Optional name prefix. It is used in Chrome for tagging detached nodes.
     714             :      */
     715          85 :     virtual const char* NamePrefix() { return nullptr; }
     716             : 
     717             :    private:
     718             :     Node(const Node&) = delete;
     719             :     Node& operator=(const Node&) = delete;
     720             :   };
     721             : 
     722             :   /**
     723             :    * Returns a node corresponding to the given V8 value. Ownership is not
     724             :    * transferred. The result pointer is valid while the graph is alive.
     725             :    */
     726             :   virtual Node* V8Node(const v8::Local<v8::Value>& value) = 0;
     727             : 
     728             :   /**
     729             :    * Adds the given node to the graph and takes ownership of the node.
     730             :    * Returns a raw pointer to the node that is valid while the graph is alive.
     731             :    */
     732             :   virtual Node* AddNode(std::unique_ptr<Node> node) = 0;
     733             : 
     734             :   /**
     735             :    * Adds an edge that represents a strong reference from the given
     736             :    * node |from| to the given node |to|. The nodes must be added to the graph
     737             :    * before calling this function.
     738             :    *
     739             :    * If name is nullptr, the edge will have auto-increment indexes, otherwise
     740             :    * it will be named accordingly.
     741             :    */
     742             :   virtual void AddEdge(Node* from, Node* to, const char* name = nullptr) = 0;
     743             : 
     744          35 :   virtual ~EmbedderGraph() = default;
     745             : };
     746             : 
     747             : /**
     748             :  * Interface for controlling heap profiling. Instance of the
     749             :  * profiler can be retrieved using v8::Isolate::GetHeapProfiler.
     750             :  */
     751             : class V8_EXPORT HeapProfiler {
     752             :  public:
     753             :   enum SamplingFlags {
     754             :     kSamplingNoFlags = 0,
     755             :     kSamplingForceGC = 1 << 0,
     756             :   };
     757             : 
     758             :   /**
     759             :    * Callback function invoked during heap snapshot generation to retrieve
     760             :    * the embedder object graph. The callback should use graph->AddEdge(..) to
     761             :    * add references between the objects.
     762             :    * The callback must not trigger garbage collection in V8.
     763             :    */
     764             :   typedef void (*BuildEmbedderGraphCallback)(v8::Isolate* isolate,
     765             :                                              v8::EmbedderGraph* graph,
     766             :                                              void* data);
     767             : 
     768             :   /** Returns the number of snapshots taken. */
     769             :   int GetSnapshotCount();
     770             : 
     771             :   /** Returns a snapshot by index. */
     772             :   const HeapSnapshot* GetHeapSnapshot(int index);
     773             : 
     774             :   /**
     775             :    * Returns SnapshotObjectId for a heap object referenced by |value| if
     776             :    * it has been seen by the heap profiler, kUnknownObjectId otherwise.
     777             :    */
     778             :   SnapshotObjectId GetObjectId(Local<Value> value);
     779             : 
     780             :   /**
     781             :    * Returns heap object with given SnapshotObjectId if the object is alive,
     782             :    * otherwise empty handle is returned.
     783             :    */
     784             :   Local<Value> FindObjectById(SnapshotObjectId id);
     785             : 
     786             :   /**
     787             :    * Clears internal map from SnapshotObjectId to heap object. The new objects
     788             :    * will not be added into it unless a heap snapshot is taken or heap object
     789             :    * tracking is kicked off.
     790             :    */
     791             :   void ClearObjectIds();
     792             : 
     793             :   /**
     794             :    * A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
     795             :    * it in case heap profiler cannot find id  for the object passed as
     796             :    * parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
     797             :    */
     798             :   static const SnapshotObjectId kUnknownObjectId = 0;
     799             : 
     800             :   /**
     801             :    * Callback interface for retrieving user friendly names of global objects.
     802             :    */
     803          25 :   class ObjectNameResolver {
     804             :    public:
     805             :     /**
     806             :      * Returns name to be used in the heap snapshot for given node. Returned
     807             :      * string must stay alive until snapshot collection is completed.
     808             :      */
     809             :     virtual const char* GetName(Local<Object> object) = 0;
     810             : 
     811             :    protected:
     812          30 :     virtual ~ObjectNameResolver() = default;
     813             :   };
     814             : 
     815             :   /**
     816             :    * Takes a heap snapshot and returns it.
     817             :    */
     818             :   const HeapSnapshot* TakeHeapSnapshot(
     819             :       ActivityControl* control = nullptr,
     820             :       ObjectNameResolver* global_object_name_resolver = nullptr);
     821             : 
     822             :   /**
     823             :    * Starts tracking of heap objects population statistics. After calling
     824             :    * this method, all heap objects relocations done by the garbage collector
     825             :    * are being registered.
     826             :    *
     827             :    * |track_allocations| parameter controls whether stack trace of each
     828             :    * allocation in the heap will be recorded and reported as part of
     829             :    * HeapSnapshot.
     830             :    */
     831             :   void StartTrackingHeapObjects(bool track_allocations = false);
     832             : 
     833             :   /**
     834             :    * Adds a new time interval entry to the aggregated statistics array. The
     835             :    * time interval entry contains information on the current heap objects
     836             :    * population size. The method also updates aggregated statistics and
     837             :    * reports updates for all previous time intervals via the OutputStream
     838             :    * object. Updates on each time interval are provided as a stream of the
     839             :    * HeapStatsUpdate structure instances.
     840             :    * If |timestamp_us| is supplied, timestamp of the new entry will be written
     841             :    * into it. The return value of the function is the last seen heap object Id.
     842             :    *
     843             :    * StartTrackingHeapObjects must be called before the first call to this
     844             :    * method.
     845             :    */
     846             :   SnapshotObjectId GetHeapStats(OutputStream* stream,
     847             :                                 int64_t* timestamp_us = nullptr);
     848             : 
     849             :   /**
     850             :    * Stops tracking of heap objects population statistics, cleans up all
     851             :    * collected data. StartHeapObjectsTracking must be called again prior to
     852             :    * calling GetHeapStats next time.
     853             :    */
     854             :   void StopTrackingHeapObjects();
     855             : 
     856             :   /**
     857             :    * Starts gathering a sampling heap profile. A sampling heap profile is
     858             :    * similar to tcmalloc's heap profiler and Go's mprof. It samples object
     859             :    * allocations and builds an online 'sampling' heap profile. At any point in
     860             :    * time, this profile is expected to be a representative sample of objects
     861             :    * currently live in the system. Each sampled allocation includes the stack
     862             :    * trace at the time of allocation, which makes this really useful for memory
     863             :    * leak detection.
     864             :    *
     865             :    * This mechanism is intended to be cheap enough that it can be used in
     866             :    * production with minimal performance overhead.
     867             :    *
     868             :    * Allocations are sampled using a randomized Poisson process. On average, one
     869             :    * allocation will be sampled every |sample_interval| bytes allocated. The
     870             :    * |stack_depth| parameter controls the maximum number of stack frames to be
     871             :    * captured on each allocation.
     872             :    *
     873             :    * NOTE: This is a proof-of-concept at this point. Right now we only sample
     874             :    * newspace allocations. Support for paged space allocation (e.g. pre-tenured
     875             :    * objects, large objects, code objects, etc.) and native allocations
     876             :    * doesn't exist yet, but is anticipated in the future.
     877             :    *
     878             :    * Objects allocated before the sampling is started will not be included in
     879             :    * the profile.
     880             :    *
     881             :    * Returns false if a sampling heap profiler is already running.
     882             :    */
     883             :   bool StartSamplingHeapProfiler(uint64_t sample_interval = 512 * 1024,
     884             :                                  int stack_depth = 16,
     885             :                                  SamplingFlags flags = kSamplingNoFlags);
     886             : 
     887             :   /**
     888             :    * Stops the sampling heap profile and discards the current profile.
     889             :    */
     890             :   void StopSamplingHeapProfiler();
     891             : 
     892             :   /**
     893             :    * Returns the sampled profile of allocations allocated (and still live) since
     894             :    * StartSamplingHeapProfiler was called. The ownership of the pointer is
     895             :    * transferred to the caller. Returns nullptr if sampling heap profiler is not
     896             :    * active.
     897             :    */
     898             :   AllocationProfile* GetAllocationProfile();
     899             : 
     900             :   /**
     901             :    * Deletes all snapshots taken. All previously returned pointers to
     902             :    * snapshots and their contents become invalid after this call.
     903             :    */
     904             :   void DeleteAllHeapSnapshots();
     905             : 
     906             :   void AddBuildEmbedderGraphCallback(BuildEmbedderGraphCallback callback,
     907             :                                      void* data);
     908             :   void RemoveBuildEmbedderGraphCallback(BuildEmbedderGraphCallback callback,
     909             :                                         void* data);
     910             : 
     911             :   /**
     912             :    * Default value of persistent handle class ID. Must not be used to
     913             :    * define a class. Can be used to reset a class of a persistent
     914             :    * handle.
     915             :    */
     916             :   static const uint16_t kPersistentHandleNoClassId = 0;
     917             : 
     918             :  private:
     919             :   HeapProfiler();
     920             :   ~HeapProfiler();
     921             :   HeapProfiler(const HeapProfiler&);
     922             :   HeapProfiler& operator=(const HeapProfiler&);
     923             : };
     924             : 
     925             : /**
     926             :  * A struct for exporting HeapStats data from V8, using "push" model.
     927             :  * See HeapProfiler::GetHeapStats.
     928             :  */
     929             : struct HeapStatsUpdate {
     930             :   HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
     931          50 :     : index(index), count(count), size(size) { }
     932             :   uint32_t index;  // Index of the time interval that was changed.
     933             :   uint32_t count;  // New value of count field for the interval with this index.
     934             :   uint32_t size;  // New value of size field for the interval with this index.
     935             : };
     936             : 
     937             : #define CODE_EVENTS_LIST(V) \
     938             :   V(Builtin)                \
     939             :   V(Callback)               \
     940             :   V(Eval)                   \
     941             :   V(Function)               \
     942             :   V(InterpretedFunction)    \
     943             :   V(Handler)                \
     944             :   V(BytecodeHandler)        \
     945             :   V(LazyCompile)            \
     946             :   V(RegExp)                 \
     947             :   V(Script)                 \
     948             :   V(Stub)
     949             : 
     950             : /**
     951             :  * Note that this enum may be extended in the future. Please include a default
     952             :  * case if this enum is used in a switch statement.
     953             :  */
     954             : enum CodeEventType {
     955             :   kUnknownType = 0
     956             : #define V(Name) , k##Name##Type
     957             :   CODE_EVENTS_LIST(V)
     958             : #undef V
     959             : };
     960             : 
     961             : /**
     962             :  * Representation of a code creation event
     963             :  */
     964             : class V8_EXPORT CodeEvent {
     965             :  public:
     966             :   uintptr_t GetCodeStartAddress();
     967             :   size_t GetCodeSize();
     968             :   Local<String> GetFunctionName();
     969             :   Local<String> GetScriptName();
     970             :   int GetScriptLine();
     971             :   int GetScriptColumn();
     972             :   /**
     973             :    * NOTE (mmarchini): We can't allocate objects in the heap when we collect
     974             :    * existing code, and both the code type and the comment are not stored in the
     975             :    * heap, so we return those as const char*.
     976             :    */
     977             :   CodeEventType GetCodeType();
     978             :   const char* GetComment();
     979             : 
     980             :   static const char* GetCodeEventTypeName(CodeEventType code_event_type);
     981             : };
     982             : 
     983             : /**
     984             :  * Interface to listen to code creation events.
     985             :  */
     986             : class V8_EXPORT CodeEventHandler {
     987             :  public:
     988             :   /**
     989             :    * Creates a new listener for the |isolate|. The isolate must be initialized.
     990             :    * The listener object must be disposed after use by calling |Dispose| method.
     991             :    * Multiple listeners can be created for the same isolate.
     992             :    */
     993             :   explicit CodeEventHandler(Isolate* isolate);
     994             :   virtual ~CodeEventHandler();
     995             : 
     996             :   virtual void Handle(CodeEvent* code_event) = 0;
     997             : 
     998             :   void Enable();
     999             :   void Disable();
    1000             : 
    1001             :  private:
    1002             :   CodeEventHandler();
    1003             :   CodeEventHandler(const CodeEventHandler&);
    1004             :   CodeEventHandler& operator=(const CodeEventHandler&);
    1005             :   void* internal_listener_;
    1006             : };
    1007             : 
    1008             : }  // namespace v8
    1009             : 
    1010             : 
    1011             : #endif  // V8_V8_PROFILER_H_

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