v8/include/v8-profiler.h
mikhail.naganov@gmail.com dee9c00267 Add an interface for an embedder to provide information about native
objects retained by object groups and global handles.

This information is then used during heap snapshot generation
to provide a more complete memory picture.

This patch will be needed to fix https://bugs.webkit.org/show_bug.cgi?id=53659.

Review URL: http://codereview.chromium.org/6626043

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7125 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2011-03-10 12:05:31 +00:00

514 lines
16 KiB
C++

// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// 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.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#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 {
/**
* 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;
};
/**
* 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>());
};
class HeapGraphNode;
/**
* HeapSnapshotEdge represents a directed connection between heap
* graph nodes: from retaners 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.
};
/** 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;
};
class V8EXPORT HeapGraphPath {
public:
/** Returns the number of edges in the path. */
int GetEdgesCount() const;
/** Returns an edge from the path. */
const HeapGraphEdge* GetEdge(int index) 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).
};
/** 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. Not applicable to aggregated heap snapshots
* as they only contain aggregated instances.
*/
uint64_t GetId() const;
/**
* Returns the number of instances. Only applicable to aggregated
* heap snapshots.
*/
int GetInstancesCount() 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.
*
* Exact retained size calculation has O(N) (number of nodes)
* computational complexity, while approximate has O(1). It is
* assumed that initially heap profiling tools provide approximate
* sizes for all nodes, and then exact sizes are calculated for the
* most 'interesting' nodes.
*/
int GetRetainedSize(bool exact) 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 the number of simple retaining paths from the root to the node. */
int GetRetainingPathsCount() const;
/** Returns a retaining path by index. */
const HeapGraphPath* GetRetainingPath(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;
};
class V8EXPORT HeapSnapshotsDiff {
public:
/** Returns the root node for added nodes. */
const HeapGraphNode* GetAdditionsRoot() const;
/** Returns the root node for deleted nodes. */
const HeapGraphNode* GetDeletionsRoot() 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.
kAggregated = 1 // Snapshot doesn't contain individual heap entries,
// instead they are grouped by constructor name.
};
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(uint64_t id) const;
/**
* Returns a diff between this snapshot and another one. Only snapshots
* of the same type can be compared.
*/
const HeapSnapshotsDiff* CompareWith(const HeapSnapshot* snapshot) const;
/**
* 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 is 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},
* nodes: [
* meta-info (JSON string),
* nodes themselves
* ],
* strings: [strings]
* }
*
* Outgoing node links are stored after each node. Nodes reference strings
* and other nodes 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);
/**
* 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);
/** 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;
};
/**
* 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 NUL-terminated UTF-8
* encoded string. V8 copies its contents during a call to GetLabel.
*/
virtual const char* GetLabel() = 0;
/**
* 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&);
};
} // namespace v8
#undef V8EXPORT
#endif // V8_V8_PROFILER_H_