v8/include/v8-profiler.h
yurys@chromium.org cec0745aa2 Introduce callback for resolving global object name while taking heap snapshot
Heap profiler currently gets "document" of global objects while taking snapshot (to later retrieve its "URL"). This is unsafe as there may be no current v8 context when the property is requested while corresponding property accessor may make some assumptions about the context stack during its invokation. Several crashes were reported due to this problem:
https://bugs.webkit.org/show_bug.cgi?id=103076
https://crbug.com/162121
https://crbug.com/132727

This patch adds a callback for resolving global object names and avoid the crashes.
Review URL: https://codereview.chromium.org/11415203

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13137 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-04 17:17:55 +00:00

581 lines
19 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) || \
(__GNUC__ == 3 && __GNUC_MINOR__ >= 3)) && defined(V8_SHARED)
#define V8EXPORT __attribute__ ((visibility("default")))
#else
#define V8EXPORT
#endif
#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 child nodes count of the node. */
int GetChildrenCount() const;
/** Retrieves a child by index. */
const HeapGraphEdge* GetChild(int index) 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;
/**
* Callback interface for retrieving user friendly names of global objects.
*/
class ObjectNameResolver {
public:
/**
* Returns name to be used in the heap snapshot for given node. Returned
* string must stay alive until snapshot collection is completed.
*/
virtual const char* GetName(Handle<Object> object) = 0;
protected:
virtual ~ObjectNameResolver() {}
};
/**
* 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,
ObjectNameResolver* global_object_name_resolver = 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_