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// Copyright 2010 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
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#ifndef V8_V8_PROFILER_H_
#define V8_V8_PROFILER_H_
#include "v8.h"
#ifdef _WIN32
// Setup for Windows DLL export/import. See v8.h in this directory for
// information on how to build/use V8 as a DLL.
#if defined(BUILDING_V8_SHARED) && defined(USING_V8_SHARED)
#error both BUILDING_V8_SHARED and USING_V8_SHARED are set - please check the\
build configuration to ensure that at most one of these is set
#endif
#ifdef BUILDING_V8_SHARED
#define V8EXPORT __declspec(dllexport)
#elif USING_V8_SHARED
#define V8EXPORT __declspec(dllimport)
#else
#define V8EXPORT
#endif
#else // _WIN32
// Setup for Linux shared library export. See v8.h in this directory for
// information on how to build/use V8 as shared library.
#if defined(__GNUC__) && (__GNUC__ >= 4) && defined(V8_SHARED)
#define V8EXPORT __attribute__ ((visibility("default")))
#else // defined(__GNUC__) && (__GNUC__ >= 4)
#define V8EXPORT
#endif // defined(__GNUC__) && (__GNUC__ >= 4)
#endif // _WIN32
/**
* Profiler support for the V8 JavaScript engine.
*/
namespace v8 {
typedef uint32_t SnapshotObjectId;
/**
* CpuProfileNode represents a node in a call graph.
*/
class V8EXPORT CpuProfileNode {
public:
/** Returns function name (empty string for anonymous functions.) */
Handle<String> GetFunctionName() const;
/** Returns resource name for script from where the function originates. */
Handle<String> GetScriptResourceName() const;
/**
* Returns the number, 1-based, of the line where the function originates.
* kNoLineNumberInfo if no line number information is available.
*/
int GetLineNumber() const;
/**
* Returns total (self + children) execution time of the function,
* in milliseconds, estimated by samples count.
*/
double GetTotalTime() const;
/**
* Returns self execution time of the function, in milliseconds,
* estimated by samples count.
*/
double GetSelfTime() const;
/** Returns the count of samples where function exists. */
double GetTotalSamplesCount() const;
/** Returns the count of samples where function was currently executing. */
double GetSelfSamplesCount() const;
/** Returns function entry UID. */
unsigned GetCallUid() const;
/** Returns child nodes count of the node. */
int GetChildrenCount() const;
/** Retrieves a child node by index. */
const CpuProfileNode* GetChild(int index) const;
static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
};
/**
* CpuProfile contains a CPU profile in a form of two call trees:
* - top-down (from main() down to functions that do all the work);
* - bottom-up call graph (in backward direction).
*/
class V8EXPORT CpuProfile {
public:
/** Returns CPU profile UID (assigned by the profiler.) */
unsigned GetUid() const;
/** Returns CPU profile title. */
Handle<String> GetTitle() const;
/** Returns the root node of the bottom up call tree. */
const CpuProfileNode* GetBottomUpRoot() const;
/** Returns the root node of the top down call tree. */
const CpuProfileNode* GetTopDownRoot() const;
/**
* Deletes the profile and removes it from CpuProfiler's list.
* All pointers to nodes previously returned become invalid.
* Profiles with the same uid but obtained using different
* security token are not deleted, but become inaccessible
* using FindProfile method. It is embedder's responsibility
* to call Delete on these profiles.
*/
void Delete();
};
/**
* Interface for controlling CPU profiling.
*/
class V8EXPORT CpuProfiler {
public:
/**
* A note on security tokens usage. As scripts from different
* origins can run inside a single V8 instance, it is possible to
* have functions from different security contexts intermixed in a
* single CPU profile. To avoid exposing function names belonging to
* other contexts, filtering by security token is performed while
* obtaining profiling results.
*/
/**
* Returns the number of profiles collected (doesn't include
* profiles that are being collected at the moment of call.)
*/
static int GetProfilesCount();
/** Returns a profile by index. */
static const CpuProfile* GetProfile(
int index,
Handle<Value> security_token = Handle<Value>());
/** Returns a profile by uid. */
static const CpuProfile* FindProfile(
unsigned uid,
Handle<Value> security_token = Handle<Value>());
/**
* Starts collecting CPU profile. Title may be an empty string. It
* is allowed to have several profiles being collected at
* once. Attempts to start collecting several profiles with the same
* title are silently ignored. While collecting a profile, functions
* from all security contexts are included in it. The token-based
* filtering is only performed when querying for a profile.
*/
static void StartProfiling(Handle<String> title);
/**
* Stops collecting CPU profile with a given title and returns it.
* If the title given is empty, finishes the last profile started.
*/
static const CpuProfile* StopProfiling(
Handle<String> title,
Handle<Value> security_token = Handle<Value>());
/**
* Deletes all existing profiles, also cancelling all profiling
* activity. All previously returned pointers to profiles and their
* contents become invalid after this call.
*/
static void DeleteAllProfiles();
};
class HeapGraphNode;
/**
* HeapSnapshotEdge represents a directed connection between heap
* graph nodes: from retainers to retained nodes.
*/
class V8EXPORT HeapGraphEdge {
public:
enum Type {
kContextVariable = 0, // A variable from a function context.
kElement = 1, // An element of an array.
kProperty = 2, // A named object property.
kInternal = 3, // A link that can't be accessed from JS,
// thus, its name isn't a real property name
// (e.g. parts of a ConsString).
kHidden = 4, // A link that is needed for proper sizes
// calculation, but may be hidden from user.
kShortcut = 5, // A link that must not be followed during
// sizes calculation.
kWeak = 6 // A weak reference (ignored by the GC).
};
/** Returns edge type (see HeapGraphEdge::Type). */
Type GetType() const;
/**
* Returns edge name. This can be a variable name, an element index, or
* a property name.
*/
Handle<Value> GetName() const;
/** Returns origin node. */
const HeapGraphNode* GetFromNode() const;
/** Returns destination node. */
const HeapGraphNode* GetToNode() const;
};
/**
* HeapGraphNode represents a node in a heap graph.
*/
class V8EXPORT HeapGraphNode {
public:
enum Type {
kHidden = 0, // Hidden node, may be filtered when shown to user.
kArray = 1, // An array of elements.
kString = 2, // A string.
kObject = 3, // A JS object (except for arrays and strings).
kCode = 4, // Compiled code.
kClosure = 5, // Function closure.
kRegExp = 6, // RegExp.
kHeapNumber = 7, // Number stored in the heap.
kNative = 8, // Native object (not from V8 heap).
kSynthetic = 9 // Synthetic object, usualy used for grouping
// snapshot items together.
};
/** Returns node type (see HeapGraphNode::Type). */
Type GetType() const;
/**
* Returns node name. Depending on node's type this can be the name
* of the constructor (for objects), the name of the function (for
* closures), string value, or an empty string (for compiled code).
*/
Handle<String> GetName() const;
/**
* Returns node id. For the same heap object, the id remains the same
* across all snapshots.
*/
SnapshotObjectId GetId() const;
/** Returns node's own size, in bytes. */
int GetSelfSize() const;
/**
* Returns node's retained size, in bytes. That is, self + sizes of
* the objects that are reachable only from this object. In other
* words, the size of memory that will be reclaimed having this node
* collected.
*/
int GetRetainedSize() const;
/** Returns child nodes count of the node. */
int GetChildrenCount() const;
/** Retrieves a child by index. */
const HeapGraphEdge* GetChild(int index) const;
/** Returns retainer nodes count of the node. */
int GetRetainersCount() const;
/** Returns a retainer by index. */
const HeapGraphEdge* GetRetainer(int index) const;
/**
* Returns a dominator node. This is the node that participates in every
* path from the snapshot root to the current node.
*/
const HeapGraphNode* GetDominatorNode() const;
/**
* Finds and returns a value from the heap corresponding to this node,
* if the value is still reachable.
*/
Handle<Value> GetHeapValue() const;
};
/**
* HeapSnapshots record the state of the JS heap at some moment.
*/
class V8EXPORT HeapSnapshot {
public:
enum Type {
kFull = 0 // Heap snapshot with all instances and references.
};
enum SerializationFormat {
kJSON = 0 // See format description near 'Serialize' method.
};
/** Returns heap snapshot type. */
Type GetType() const;
/** Returns heap snapshot UID (assigned by the profiler.) */
unsigned GetUid() const;
/** Returns heap snapshot title. */
Handle<String> GetTitle() const;
/** Returns the root node of the heap graph. */
const HeapGraphNode* GetRoot() const;
/** Returns a node by its id. */
const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
/** Returns total nodes count in the snapshot. */
int GetNodesCount() const;
/** Returns a node by index. */
const HeapGraphNode* GetNode(int index) const;
/** Returns a max seen JS object Id. */
SnapshotObjectId GetMaxSnapshotJSObjectId() const;
/**
* Deletes the snapshot and removes it from HeapProfiler's list.
* All pointers to nodes, edges and paths previously returned become
* invalid.
*/
void Delete();
/**
* Prepare a serialized representation of the snapshot. The result
* is written into the stream provided in chunks of specified size.
* The total length of the serialized snapshot is unknown in
* advance, it can be roughly equal to JS heap size (that means,
* it can be really big - tens of megabytes).
*
* For the JSON format, heap contents are represented as an object
* with the following structure:
*
* {
* snapshot: {
* title: "...",
* uid: nnn,
* meta: { meta-info },
* node_count: nnn,
* edge_count: nnn
* },
* nodes: [nodes array],
* edges: [edges array],
* strings: [strings array]
* }
*
* Nodes reference strings, other nodes, and edges by their indexes
* in corresponding arrays.
*/
void Serialize(OutputStream* stream, SerializationFormat format) const;
};
class RetainedObjectInfo;
/**
* Interface for controlling heap profiling.
*/
class V8EXPORT HeapProfiler {
public:
/**
* Callback function invoked for obtaining RetainedObjectInfo for
* the given JavaScript wrapper object. It is prohibited to enter V8
* while the callback is running: only getters on the handle and
* GetPointerFromInternalField on the objects are allowed.
*/
typedef RetainedObjectInfo* (*WrapperInfoCallback)
(uint16_t class_id, Handle<Value> wrapper);
/** Returns the number of snapshots taken. */
static int GetSnapshotsCount();
/** Returns a snapshot by index. */
static const HeapSnapshot* GetSnapshot(int index);
/** Returns a profile by uid. */
static const HeapSnapshot* FindSnapshot(unsigned uid);
/**
* Returns SnapshotObjectId for a heap object referenced by |value| if
* it has been seen by the heap profiler, kUnknownObjectId otherwise.
*/
static SnapshotObjectId GetSnapshotObjectId(Handle<Value> value);
/**
* A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
* it in case heap profiler cannot find id for the object passed as
* parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
*/
static const SnapshotObjectId kUnknownObjectId = 0;
/**
* Takes a heap snapshot and returns it. Title may be an empty string.
* See HeapSnapshot::Type for types description.
*/
static const HeapSnapshot* TakeSnapshot(
Handle<String> title,
HeapSnapshot::Type type = HeapSnapshot::kFull,
ActivityControl* control = NULL);
/**
* Starts tracking of heap objects population statistics. After calling
* this method, all heap objects relocations done by the garbage collector
* are being registered.
*/
static void StartHeapObjectsTracking();
/**
* Adds a new time interval entry to the aggregated statistics array. The
* time interval entry contains information on the current heap objects
* population size. The method also updates aggregated statistics and
* reports updates for all previous time intervals via the OutputStream
* object. Updates on each time interval are provided as a stream of the
* HeapStatsUpdate structure instances.
* The return value of the function is the last seen heap object Id.
*
* StartHeapObjectsTracking must be called before the first call to this
* method.
*/
static SnapshotObjectId PushHeapObjectsStats(OutputStream* stream);
/**
* Stops tracking of heap objects population statistics, cleans up all
* collected data. StartHeapObjectsTracking must be called again prior to
* calling PushHeapObjectsStats next time.
*/
static void StopHeapObjectsTracking();
/**
* Deletes all snapshots taken. All previously returned pointers to
* snapshots and their contents become invalid after this call.
*/
static void DeleteAllSnapshots();
/** Binds a callback to embedder's class ID. */
static void DefineWrapperClass(
uint16_t class_id,
WrapperInfoCallback callback);
/**
* Default value of persistent handle class ID. Must not be used to
* define a class. Can be used to reset a class of a persistent
* handle.
*/
static const uint16_t kPersistentHandleNoClassId = 0;
/** Returns the number of currently existing persistent handles. */
static int GetPersistentHandleCount();
/** Returns memory used for profiler internal data and snapshots. */
static size_t GetMemorySizeUsedByProfiler();
};
/**
* Interface for providing information about embedder's objects
* held by global handles. This information is reported in two ways:
*
* 1. When calling AddObjectGroup, an embedder may pass
* RetainedObjectInfo instance describing the group. To collect
* this information while taking a heap snapshot, V8 calls GC
* prologue and epilogue callbacks.
*
* 2. When a heap snapshot is collected, V8 additionally
* requests RetainedObjectInfos for persistent handles that
* were not previously reported via AddObjectGroup.
*
* Thus, if an embedder wants to provide information about native
* objects for heap snapshots, he can do it in a GC prologue
* handler, and / or by assigning wrapper class ids in the following way:
*
* 1. Bind a callback to class id by calling DefineWrapperClass.
* 2. Call SetWrapperClassId on certain persistent handles.
*
* V8 takes ownership of RetainedObjectInfo instances passed to it and
* keeps them alive only during snapshot collection. Afterwards, they
* are freed by calling the Dispose class function.
*/
class V8EXPORT RetainedObjectInfo { // NOLINT
public:
/** Called by V8 when it no longer needs an instance. */
virtual void Dispose() = 0;
/** Returns whether two instances are equivalent. */
virtual bool IsEquivalent(RetainedObjectInfo* other) = 0;
/**
* Returns hash value for the instance. Equivalent instances
* must have the same hash value.
*/
virtual intptr_t GetHash() = 0;
/**
* Returns human-readable label. It must be a null-terminated UTF-8
* encoded string. V8 copies its contents during a call to GetLabel.
*/
virtual const char* GetLabel() = 0;
/**
* Returns human-readable group label. It must be a null-terminated UTF-8
* encoded string. V8 copies its contents during a call to GetGroupLabel.
* Heap snapshot generator will collect all the group names, create
* top level entries with these names and attach the objects to the
* corresponding top level group objects. There is a default
* implementation which is required because embedders don't have their
* own implementation yet.
*/
virtual const char* GetGroupLabel() { return GetLabel(); }
/**
* Returns element count in case if a global handle retains
* a subgraph by holding one of its nodes.
*/
virtual intptr_t GetElementCount() { return -1; }
/** Returns embedder's object size in bytes. */
virtual intptr_t GetSizeInBytes() { return -1; }
protected:
RetainedObjectInfo() {}
virtual ~RetainedObjectInfo() {}
private:
RetainedObjectInfo(const RetainedObjectInfo&);
RetainedObjectInfo& operator=(const RetainedObjectInfo&);
};
/**
* A struct for exporting HeapStats data from V8, using "push" model.
* See HeapProfiler::PushHeapObjectsStats.
*/
struct HeapStatsUpdate {
HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
: index(index), count(count), size(size) { }
uint32_t index; // Index of the time interval that was changed.
uint32_t count; // New value of count field for the interval with this index.
uint32_t size; // New value of size field for the interval with this index.
};
} // namespace v8
#undef V8EXPORT
#endif // V8_V8_PROFILER_H_