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| 1 // Copyright 2011 the V8 project authors. All rights reserved. | |
| 2 // Redistribution and use in source and binary forms, with or without | |
| 3 // modification, are permitted provided that the following conditions are | |
| 4 // met: | |
| 5 // | |
| 6 // * Redistributions of source code must retain the above copyright | |
| 7 // notice, this list of conditions and the following disclaimer. | |
| 8 // * Redistributions in binary form must reproduce the above | |
| 9 // copyright notice, this list of conditions and the following | |
| 10 // disclaimer in the documentation and/or other materials provided | |
| 11 // with the distribution. | |
| 12 // * Neither the name of Google Inc. nor the names of its | |
| 13 // contributors may be used to endorse or promote products derived | |
| 14 // from this software without specific prior written permission. | |
| 15 // | |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 | |
| 28 #ifndef V8_LIVEOBJECTLIST_H_ | |
| 29 #define V8_LIVEOBJECTLIST_H_ | |
| 30 | |
| 31 #include "v8.h" | |
| 32 | |
| 33 #include "checks.h" | |
| 34 #include "heap.h" | |
| 35 #include "objects.h" | |
| 36 #include "globals.h" | |
| 37 | |
| 38 namespace v8 { | |
| 39 namespace internal { | |
| 40 | |
| 41 #ifdef LIVE_OBJECT_LIST | |
| 42 | |
| 43 #ifdef DEBUG | |
| 44 // The following symbol when defined enables thorough verification of lol data. | |
| 45 // FLAG_verify_lol will also need to set to true to enable the verification. | |
| 46 #define VERIFY_LOL | |
| 47 #endif | |
| 48 | |
| 49 | |
| 50 typedef int LiveObjectType; | |
| 51 class LolFilter; | |
| 52 class LiveObjectSummary; | |
| 53 class DumpWriter; | |
| 54 class SummaryWriter; | |
| 55 | |
| 56 | |
| 57 // The LiveObjectList is both a mechanism for tracking a live capture of | |
| 58 // objects in the JS heap, as well as is the data structure which represents | |
| 59 // each of those captures. Unlike a snapshot, the lol is live. For example, | |
| 60 // if an object in a captured lol dies and is collected by the GC, the lol | |
| 61 // will reflect that the object is no longer available. The term | |
| 62 // LiveObjectList (and lol) is used to describe both the mechanism and the | |
| 63 // data structure depending on context of use. | |
| 64 // | |
| 65 // In captured lols, objects are tracked using their address and an object id. | |
| 66 // The object id is unique. Once assigned to an object, the object id can never | |
| 67 // be assigned to another object. That is unless all captured lols are deleted | |
| 68 // which allows the user to start over with a fresh set of lols and object ids. | |
| 69 // The uniqueness of the object ids allows the user to track specific objects | |
| 70 // and inspect its longevity while debugging JS code in execution. | |
| 71 // | |
| 72 // The lol comes with utility functions to capture, dump, summarize, and diff | |
| 73 // captured lols amongst other functionality. These functionality are | |
| 74 // accessible via the v8 debugger interface. | |
| 75 class LiveObjectList { | |
| 76 public: | |
| 77 inline static void GCEpilogue(); | |
| 78 inline static void GCPrologue(); | |
| 79 inline static void IterateElements(ObjectVisitor* v); | |
| 80 inline static void ProcessNonLive(HeapObject* obj); | |
| 81 inline static void UpdateReferencesForScavengeGC(); | |
| 82 | |
| 83 // Note: LOLs can be listed by calling Dump(0, <lol id>), and 2 LOLs can be | |
| 84 // compared/diff'ed using Dump(<lol id1>, <lol id2>, ...). This will yield | |
| 85 // a verbose dump of all the objects in the resultant lists. | |
| 86 // Similarly, a summarized result of a LOL listing or a diff can be | |
| 87 // attained using the Summarize(0, <lol id>) and Summarize(<lol id1, | |
| 88 // <lol id2>, ...) respectively. | |
| 89 | |
| 90 static MaybeObject* Capture(); | |
| 91 static bool Delete(int id); | |
| 92 static MaybeObject* Dump(int id1, | |
| 93 int id2, | |
| 94 int start_idx, | |
| 95 int dump_limit, | |
| 96 Handle<JSObject> filter_obj); | |
| 97 static MaybeObject* Info(int start_idx, int dump_limit); | |
| 98 static MaybeObject* Summarize(int id1, int id2, Handle<JSObject> filter_obj); | |
| 99 | |
| 100 static void Reset(); | |
| 101 static Object* GetObj(int obj_id); | |
| 102 static int GetObjId(Object* obj); | |
| 103 static Object* GetObjId(Handle<String> address); | |
| 104 static MaybeObject* GetObjRetainers(int obj_id, | |
| 105 Handle<JSObject> instance_filter, | |
| 106 bool verbose, | |
| 107 int start, | |
| 108 int count, | |
| 109 Handle<JSObject> filter_obj); | |
| 110 | |
| 111 static Object* GetPath(int obj_id1, | |
| 112 int obj_id2, | |
| 113 Handle<JSObject> instance_filter); | |
| 114 static Object* PrintObj(int obj_id); | |
| 115 | |
| 116 private: | |
| 117 struct Element { | |
| 118 int id_; | |
| 119 HeapObject* obj_; | |
| 120 }; | |
| 121 | |
| 122 explicit LiveObjectList(LiveObjectList* prev, int capacity); | |
| 123 ~LiveObjectList(); | |
| 124 | |
| 125 static void GCEpiloguePrivate(); | |
| 126 static void IterateElementsPrivate(ObjectVisitor* v); | |
| 127 | |
| 128 static void DoProcessNonLive(HeapObject* obj); | |
| 129 | |
| 130 static int CompareElement(const Element* a, const Element* b); | |
| 131 | |
| 132 static Object* GetPathPrivate(HeapObject* obj1, HeapObject* obj2); | |
| 133 | |
| 134 static int GetRetainers(Handle<HeapObject> target, | |
| 135 Handle<JSObject> instance_filter, | |
| 136 Handle<FixedArray> retainers_arr, | |
| 137 int start, | |
| 138 int dump_limit, | |
| 139 int* total_count, | |
| 140 LolFilter* filter, | |
| 141 LiveObjectSummary* summary, | |
| 142 JSFunction* arguments_function, | |
| 143 Handle<Object> error); | |
| 144 | |
| 145 static MaybeObject* DumpPrivate(DumpWriter* writer, | |
| 146 int start, | |
| 147 int dump_limit, | |
| 148 LolFilter* filter); | |
| 149 static MaybeObject* SummarizePrivate(SummaryWriter* writer, | |
| 150 LolFilter* filter, | |
| 151 bool is_tracking_roots); | |
| 152 | |
| 153 static bool NeedLOLProcessing() { return (last() != NULL); } | |
| 154 static void NullifyNonLivePointer(HeapObject** p) { | |
| 155 // Mask out the low bit that marks this as a heap object. We'll use this | |
| 156 // cleared bit as an indicator that this pointer needs to be collected. | |
| 157 // | |
| 158 // Meanwhile, we still preserve its approximate value so that we don't | |
| 159 // have to resort the elements list all the time. | |
| 160 // | |
| 161 // Note: Doing so also makes this HeapObject* look like an SMI. Hence, | |
| 162 // GC pointer updater will ignore it when it gets scanned. | |
| 163 *p = reinterpret_cast<HeapObject*>((*p)->address()); | |
| 164 } | |
| 165 | |
| 166 LiveObjectList* prev() { return prev_; } | |
| 167 LiveObjectList* next() { return next_; } | |
| 168 int id() { return id_; } | |
| 169 | |
| 170 static int list_count() { return list_count_; } | |
| 171 static LiveObjectList* last() { return last_; } | |
| 172 | |
| 173 inline static LiveObjectList* FindLolForId(int id, LiveObjectList* start_lol); | |
| 174 int TotalObjCount() { return GetTotalObjCountAndSize(NULL); } | |
| 175 int GetTotalObjCountAndSize(int* size_p); | |
| 176 | |
| 177 bool Add(HeapObject* obj); | |
| 178 Element* Find(HeapObject* obj); | |
| 179 static void NullifyMostRecent(HeapObject* obj); | |
| 180 void Sort(); | |
| 181 static void SortAll(); | |
| 182 | |
| 183 static void PurgeDuplicates(); // Only to be called by GCEpilogue. | |
| 184 | |
| 185 #ifdef VERIFY_LOL | |
| 186 static void Verify(bool match_heap_exactly = false); | |
| 187 static void VerifyNotInFromSpace(); | |
| 188 #endif | |
| 189 | |
| 190 // Iterates the elements in every lol and returns the one that matches the | |
| 191 // specified key. If no matching element is found, then it returns NULL. | |
| 192 template <typename T> | |
| 193 inline static LiveObjectList::Element* | |
| 194 FindElementFor(T (*GetValue)(LiveObjectList::Element*), T key); | |
| 195 | |
| 196 inline static int GetElementId(Element* element); | |
| 197 inline static HeapObject* GetElementObj(Element* element); | |
| 198 | |
| 199 // Instance fields. | |
| 200 LiveObjectList* prev_; | |
| 201 LiveObjectList* next_; | |
| 202 int id_; | |
| 203 int capacity_; | |
| 204 int obj_count_; | |
| 205 Element* elements_; | |
| 206 | |
| 207 // Statics for managing all the lists. | |
| 208 static uint32_t next_element_id_; | |
| 209 static int list_count_; | |
| 210 static int last_id_; | |
| 211 static LiveObjectList* first_; | |
| 212 static LiveObjectList* last_; | |
| 213 | |
| 214 friend class LolIterator; | |
| 215 friend class LolForwardIterator; | |
| 216 friend class LolDumpWriter; | |
| 217 friend class RetainersDumpWriter; | |
| 218 friend class RetainersSummaryWriter; | |
| 219 friend class UpdateLiveObjectListVisitor; | |
| 220 }; | |
| 221 | |
| 222 | |
| 223 // Helper class for updating the LiveObjectList HeapObject pointers. | |
| 224 class UpdateLiveObjectListVisitor: public ObjectVisitor { | |
| 225 public: | |
| 226 void VisitPointer(Object** p) { UpdatePointer(p); } | |
| 227 | |
| 228 void VisitPointers(Object** start, Object** end) { | |
| 229 // Copy all HeapObject pointers in [start, end). | |
| 230 for (Object** p = start; p < end; p++) UpdatePointer(p); | |
| 231 } | |
| 232 | |
| 233 private: | |
| 234 // Based on Heap::ScavengeObject() but only does forwarding of pointers | |
| 235 // to live new space objects, and not actually keep them alive. | |
| 236 void UpdatePointer(Object** p) { | |
| 237 Object* object = *p; | |
| 238 if (!HEAP->InNewSpace(object)) return; | |
| 239 | |
| 240 HeapObject* heap_obj = HeapObject::cast(object); | |
| 241 ASSERT(HEAP->InFromSpace(heap_obj)); | |
| 242 | |
| 243 // We use the first word (where the map pointer usually is) of a heap | |
| 244 // object to record the forwarding pointer. A forwarding pointer can | |
| 245 // point to an old space, the code space, or the to space of the new | |
| 246 // generation. | |
| 247 MapWord first_word = heap_obj->map_word(); | |
| 248 | |
| 249 // If the first word is a forwarding address, the object has already been | |
| 250 // copied. | |
| 251 if (first_word.IsForwardingAddress()) { | |
| 252 *p = first_word.ToForwardingAddress(); | |
| 253 return; | |
| 254 | |
| 255 // Else, it's a dead object. | |
| 256 } else { | |
| 257 LiveObjectList::NullifyNonLivePointer(reinterpret_cast<HeapObject**>(p)); | |
| 258 } | |
| 259 } | |
| 260 }; | |
| 261 | |
| 262 | |
| 263 #else // !LIVE_OBJECT_LIST | |
| 264 | |
| 265 | |
| 266 class LiveObjectList { | |
| 267 public: | |
| 268 inline static void GCEpilogue() {} | |
| 269 inline static void GCPrologue() {} | |
| 270 inline static void IterateElements(ObjectVisitor* v) {} | |
| 271 inline static void ProcessNonLive(HeapObject* obj) {} | |
| 272 inline static void UpdateReferencesForScavengeGC() {} | |
| 273 | |
| 274 inline static MaybeObject* Capture() { return HEAP->undefined_value(); } | |
| 275 inline static bool Delete(int id) { return false; } | |
| 276 inline static MaybeObject* Dump(int id1, | |
| 277 int id2, | |
| 278 int start_idx, | |
| 279 int dump_limit, | |
| 280 Handle<JSObject> filter_obj) { | |
| 281 return HEAP->undefined_value(); | |
| 282 } | |
| 283 inline static MaybeObject* Info(int start_idx, int dump_limit) { | |
| 284 return HEAP->undefined_value(); | |
| 285 } | |
| 286 inline static MaybeObject* Summarize(int id1, | |
| 287 int id2, | |
| 288 Handle<JSObject> filter_obj) { | |
| 289 return HEAP->undefined_value(); | |
| 290 } | |
| 291 | |
| 292 inline static void Reset() {} | |
| 293 inline static Object* GetObj(int obj_id) { return HEAP->undefined_value(); } | |
| 294 inline static Object* GetObjId(Handle<String> address) { | |
| 295 return HEAP->undefined_value(); | |
| 296 } | |
| 297 inline static MaybeObject* GetObjRetainers(int obj_id, | |
| 298 Handle<JSObject> instance_filter, | |
| 299 bool verbose, | |
| 300 int start, | |
| 301 int count, | |
| 302 Handle<JSObject> filter_obj) { | |
| 303 return HEAP->undefined_value(); | |
| 304 } | |
| 305 | |
| 306 inline static Object* GetPath(int obj_id1, | |
| 307 int obj_id2, | |
| 308 Handle<JSObject> instance_filter) { | |
| 309 return HEAP->undefined_value(); | |
| 310 } | |
| 311 inline static Object* PrintObj(int obj_id) { return HEAP->undefined_value(); } | |
| 312 }; | |
| 313 | |
| 314 | |
| 315 #endif // LIVE_OBJECT_LIST | |
| 316 | |
| 317 } } // namespace v8::internal | |
| 318 | |
| 319 #endif // V8_LIVEOBJECTLIST_H_ | |
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Chromium Code Reviews
Issue 11975012:
Remove support for Live Object List and inspector module. (Closed)
Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge