DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (b6d82b1a6b02)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jsapi.h"

#include "js/RootingAPI.h"
#include "js/SliceBudget.h"
#include "jsapi-tests/tests.h"
#include "vm/Realm.h"

static bool ConstructCCW(JSContext* cx, const JSClass* globalClasp,
                         JS::HandleObject global1,
                         JS::MutableHandleObject wrapper,
                         JS::MutableHandleObject global2,
                         JS::MutableHandleObject wrappee) {
  if (!global1) {
    fprintf(stderr, "null initial global");
    return false;
  }

  // Define a second global in a different zone.
  JS::RealmOptions options;
  global2.set(JS_NewGlobalObject(cx, globalClasp, nullptr,
                                 JS::FireOnNewGlobalHook, options));
  if (!global2) {
    fprintf(stderr, "failed to create second global");
    return false;
  }

  // This should always be false, regardless.
  if (global1->compartment() == global2->compartment()) {
    fprintf(stderr, "second global claims to be in global1's compartment");
    return false;
  }

  // This checks that the API obeys the implicit zone request.
  if (global1->zone() == global2->zone()) {
    fprintf(stderr, "global2 is in global1's zone");
    return false;
  }

  // Define an object in compartment 2, that is wrapped by a CCW into
  // compartment 1.
  {
    JSAutoRealm ar(cx, global2);
    wrappee.set(JS_NewPlainObject(cx));
    if (wrappee->compartment() != global2->compartment()) {
      fprintf(stderr, "wrappee in wrong compartment");
      return false;
    }
  }

  wrapper.set(wrappee);
  if (!JS_WrapObject(cx, wrapper)) {
    fprintf(stderr, "failed to wrap");
    return false;
  }
  if (wrappee == wrapper) {
    fprintf(stderr, "expected wrapping");
    return false;
  }
  if (wrapper->compartment() != global1->compartment()) {
    fprintf(stderr, "wrapper in wrong compartment");
    return false;
  }

  return true;
}

class CCWTestTracer final : public JS::CallbackTracer {
  bool onChild(const JS::GCCellPtr& thing) override {
    numberOfThingsTraced++;

    printf("*thingp         = %p\n", thing.asCell());
    printf("*expectedThingp = %p\n", *expectedThingp);

    printf("kind         = %d\n", static_cast<int>(thing.kind()));
    printf("expectedKind = %d\n", static_cast<int>(expectedKind));

    if (thing.asCell() != *expectedThingp || thing.kind() != expectedKind) {
      okay = false;
    }
    return true;
  }

 public:
  bool okay;
  size_t numberOfThingsTraced;
  void** expectedThingp;
  JS::TraceKind expectedKind;

  CCWTestTracer(JSContext* cx, void** expectedThingp,
                JS::TraceKind expectedKind)
      : JS::CallbackTracer(cx),
        okay(true),
        numberOfThingsTraced(0),
        expectedThingp(expectedThingp),
        expectedKind(expectedKind) {}
};

BEGIN_TEST(testTracingIncomingCCWs) {
#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif
  JS_GC(cx);

  JS::RootedObject global1(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrapper(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject global2(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrappee(cx, JS::CurrentGlobalOrNull(cx));
  CHECK(ConstructCCW(cx, getGlobalClass(), global1, &wrapper, &global2,
                     &wrappee));
  JS_GC(cx);
  CHECK(!js::gc::IsInsideNursery(wrappee));
  CHECK(!js::gc::IsInsideNursery(wrapper));

  JS::RootedValue v(cx, JS::ObjectValue(*wrapper));
  CHECK(JS_SetProperty(cx, global1, "ccw", v));

  // Ensure that |TraceIncomingCCWs| finds the object wrapped by the CCW.

  JS::CompartmentSet compartments;
  CHECK(compartments.put(global2->compartment()));

  void* thing = wrappee.get();
  CCWTestTracer trc(cx, &thing, JS::TraceKind::Object);
  JS::TraceIncomingCCWs(&trc, compartments);
  CHECK(trc.numberOfThingsTraced == 1);
  CHECK(trc.okay);

  return true;
}
END_TEST(testTracingIncomingCCWs)

static size_t countObjectWrappers(JS::Compartment* comp) {
  size_t count = 0;
  for (JS::Compartment::ObjectWrapperEnum e(comp); !e.empty(); e.popFront()) {
    ++count;
  }
  return count;
}

BEGIN_TEST(testDeadNurseryCCW) {
#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif
  JS_GC(cx);

  JS::RootedObject global1(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrapper(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject global2(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrappee(cx, JS::CurrentGlobalOrNull(cx));
  CHECK(ConstructCCW(cx, getGlobalClass(), global1, &wrapper, &global2,
                     &wrappee));
  CHECK(js::gc::IsInsideNursery(wrappee));
  CHECK(js::gc::IsInsideNursery(wrapper));

  // Now let the obj and wrapper die.
  wrappee = wrapper = nullptr;

  // Now a GC should clear the CCW.
  CHECK(countObjectWrappers(global1->compartment()) == 1);
  cx->runtime()->gc.evictNursery();
  CHECK(countObjectWrappers(global1->compartment()) == 0);

  // Check for corruption of the CCW table by doing a full GC to force sweeping.
  JS_GC(cx);

  return true;
}
END_TEST(testDeadNurseryCCW)

BEGIN_TEST(testLiveNurseryCCW) {
#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif
  JS_GC(cx);

  JS::RootedObject global1(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrapper(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject global2(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrappee(cx, JS::CurrentGlobalOrNull(cx));
  CHECK(ConstructCCW(cx, getGlobalClass(), global1, &wrapper, &global2,
                     &wrappee));
  CHECK(js::gc::IsInsideNursery(wrappee));
  CHECK(js::gc::IsInsideNursery(wrapper));

  // Now a GC should not kill the CCW.
  CHECK(countObjectWrappers(global1->compartment()) == 1);
  cx->runtime()->gc.evictNursery();
  CHECK(countObjectWrappers(global1->compartment()) == 1);

  CHECK(!js::gc::IsInsideNursery(wrappee));
  CHECK(!js::gc::IsInsideNursery(wrapper));

  // Check for corruption of the CCW table by doing a full GC to force sweeping.
  JS_GC(cx);

  return true;
}
END_TEST(testLiveNurseryCCW)

BEGIN_TEST(testLiveNurseryWrapperCCW) {
#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif
  JS_GC(cx);

  JS::RootedObject global1(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrapper(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject global2(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrappee(cx, JS::CurrentGlobalOrNull(cx));
  CHECK(ConstructCCW(cx, getGlobalClass(), global1, &wrapper, &global2,
                     &wrappee));
  CHECK(js::gc::IsInsideNursery(wrappee));
  CHECK(js::gc::IsInsideNursery(wrapper));

  // The wrapper contains a strong reference to the wrappee, so just dropping
  // the reference to the wrappee will not drop the CCW table entry as long
  // as the wrapper is held strongly. Thus, the minor collection here must
  // tenure both the wrapper and the wrappee and keep both in the table.
  wrappee = nullptr;

  // Now a GC should not kill the CCW.
  CHECK(countObjectWrappers(global1->compartment()) == 1);
  cx->runtime()->gc.evictNursery();
  CHECK(countObjectWrappers(global1->compartment()) == 1);

  CHECK(!js::gc::IsInsideNursery(wrapper));

  // Check for corruption of the CCW table by doing a full GC to force sweeping.
  JS_GC(cx);

  return true;
}
END_TEST(testLiveNurseryWrapperCCW)

BEGIN_TEST(testLiveNurseryWrappeeCCW) {
#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif
  JS_GC(cx);

  JS::RootedObject global1(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrapper(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject global2(cx, JS::CurrentGlobalOrNull(cx));
  JS::RootedObject wrappee(cx, JS::CurrentGlobalOrNull(cx));
  CHECK(ConstructCCW(cx, getGlobalClass(), global1, &wrapper, &global2,
                     &wrappee));
  CHECK(js::gc::IsInsideNursery(wrappee));
  CHECK(js::gc::IsInsideNursery(wrapper));

  // Let the wrapper die. The wrapper should drop from the table when we GC,
  // even though there are other non-cross-compartment edges to it.
  wrapper = nullptr;

  // Now a GC should not kill the CCW.
  CHECK(countObjectWrappers(global1->compartment()) == 1);
  cx->runtime()->gc.evictNursery();
  CHECK(countObjectWrappers(global1->compartment()) == 0);

  CHECK(!js::gc::IsInsideNursery(wrappee));

  // Check for corruption of the CCW table by doing a full GC to force sweeping.
  JS_GC(cx);

  return true;
}
END_TEST(testLiveNurseryWrappeeCCW)

BEGIN_TEST(testIncrementalRoots) {
  JSRuntime* rt = cx->runtime();

#ifdef JS_GC_ZEAL
  // Disable zeal modes because this test needs to control exactly when the GC
  // happens.
  JS_SetGCZeal(cx, 0, 100);
#endif

  // Construct a big object graph to mark. In JS, the resulting object graph
  // is equivalent to:
  //
  //   leaf = {};
  //   leaf2 = {};
  //   root = { 'obj': { 'obj': ... { 'obj': leaf, 'leaf2': leaf2 } ... } }
  //
  // with leafOwner the object that has the 'obj' and 'leaf2' properties.

  JS::RootedObject obj(cx, JS_NewObject(cx, nullptr));
  if (!obj) {
    return false;
  }

  JS::RootedObject root(cx, obj);

  JS::RootedObject leaf(cx);
  JS::RootedObject leafOwner(cx);

  for (size_t i = 0; i < 3000; i++) {
    JS::RootedObject subobj(cx, JS_NewObject(cx, nullptr));
    if (!subobj) {
      return false;
    }
    if (!JS_DefineProperty(cx, obj, "obj", subobj, 0)) {
      return false;
    }
    leafOwner = obj;
    obj = subobj;
    leaf = subobj;
  }

  // Give the leaf owner a second leaf.
  {
    JS::RootedObject leaf2(cx, JS_NewObject(cx, nullptr));
    if (!leaf2) {
      return false;
    }
    if (!JS_DefineProperty(cx, leafOwner, "leaf2", leaf2, 0)) {
      return false;
    }
  }

  // This is marked during markRuntime
  JS::RootedObjectVector vec(cx);
  if (!vec.append(root)) {
    return false;
  }

  // Tenure everything so intentionally unrooted objects don't move before we
  // can use them.
  cx->runtime()->gc.minorGC(JS::GCReason::API);

  // Release all roots except for the RootedObjectVector.
  obj = root = nullptr;

  // We need to manipulate interior nodes, but the JSAPI understandably wants
  // to make it difficult to do that without rooting things on the stack (by
  // requiring Handle parameters). We can do it anyway by using
  // fromMarkedLocation. The hazard analysis is OK with this because the
  // unrooted variables are not live after they've been pointed to via
  // fromMarkedLocation; you're essentially lying to the analysis, saying
  // that the unrooted variables are rooted.
  //
  // The analysis will report this lie in its listing of "unsafe references",
  // but we do not break the build based on those as there are too many false
  // positives.
  JSObject* unrootedLeaf = leaf;
  JS::Value unrootedLeafValue = JS::ObjectValue(*leaf);
  JSObject* unrootedLeafOwner = leafOwner;
  JS::HandleObject leafHandle =
      JS::HandleObject::fromMarkedLocation(&unrootedLeaf);
  JS::HandleValue leafValueHandle =
      JS::HandleValue::fromMarkedLocation(&unrootedLeafValue);
  JS::HandleObject leafOwnerHandle =
      JS::HandleObject::fromMarkedLocation(&unrootedLeafOwner);
  leaf = leafOwner = nullptr;

  // Do the root marking slice. This should mark 'root' and a bunch of its
  // descendants. It shouldn't make it all the way through (it gets a budget
  // of 1000, and the graph is about 3000 objects deep).
  js::SliceBudget budget(js::WorkBudget(1000));
  JS_SetGCParameter(cx, JSGC_MODE, JSGC_MODE_ZONE_INCREMENTAL);
  rt->gc.startDebugGC(GC_NORMAL, budget);

  // We'd better be between iGC slices now. There's always a risk that
  // something will decide that we need to do a full GC (such as gczeal, but
  // that is turned off.)
  MOZ_ASSERT(JS::IsIncrementalGCInProgress(cx));

  // And assert that the mark bits are as we expect them to be.
  MOZ_ASSERT(vec[0]->asTenured().isMarkedBlack());
  MOZ_ASSERT(!leafHandle->asTenured().isMarkedBlack());
  MOZ_ASSERT(!leafOwnerHandle->asTenured().isMarkedBlack());

#ifdef DEBUG
  // Remember the current GC number so we can assert that no GC occurs
  // between operations.
  auto currentGCNumber = rt->gc.gcNumber();
#endif

  // Now do the incremental GC's worst nightmare: rip an unmarked object
  // 'leaf' out of the graph and stick it into an already-marked region (hang
  // it off the un-prebarriered root, in fact). The pre-barrier on the
  // overwrite of the source location should cause this object to be marked.
  if (!JS_SetProperty(cx, leafOwnerHandle, "obj", JS::UndefinedHandleValue)) {
    return false;
  }
  MOZ_ASSERT(rt->gc.gcNumber() == currentGCNumber);
  if (!JS_SetProperty(cx, vec[0], "newobj", leafValueHandle)) {
    return false;
  }
  MOZ_ASSERT(rt->gc.gcNumber() == currentGCNumber);
  MOZ_ASSERT(leafHandle->asTenured().isMarkedBlack());

  // Also take an unmarked object 'leaf2' from the graph and add an
  // additional edge from the root to it. This will not be marked by any
  // pre-barrier, but it is still in the live graph so it will eventually get
  // marked.
  //
  // Note that the root->leaf2 edge will *not* be marked through, since the
  // root is already marked, but that only matters if doing a compacting GC
  // and the compacting GC repeats the whole marking phase to update
  // pointers.
  {
    JS::RootedValue leaf2(cx);
    if (!JS_GetProperty(cx, leafOwnerHandle, "leaf2", &leaf2)) {
      return false;
    }
    MOZ_ASSERT(rt->gc.gcNumber() == currentGCNumber);
    MOZ_ASSERT(!leaf2.toObject().asTenured().isMarkedBlack());
    if (!JS_SetProperty(cx, vec[0], "leafcopy", leaf2)) {
      return false;
    }
    MOZ_ASSERT(rt->gc.gcNumber() == currentGCNumber);
    MOZ_ASSERT(!leaf2.toObject().asTenured().isMarkedBlack());
  }

  // Finish the GC using an unlimited budget.
  auto unlimited = js::SliceBudget::unlimited();
  rt->gc.debugGCSlice(unlimited);

  // Access the leaf object to try to trigger a crash if it is dead.
  if (!JS_SetProperty(cx, leafHandle, "toes", JS::UndefinedHandleValue)) {
    return false;
  }

  return true;
}
END_TEST(testIncrementalRoots)