summaryrefslogtreecommitdiffstats
path: root/js/src/jsapi-tests/testGCMarking.cpp
blob: b475c2d696f16e7bd04900637951386b20bc8ce6 (plain)
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
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
*/
/* 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 "jscompartment.h"

#include "js/RootingAPI.h"
#include "js/SliceBudget.h"
#include "jsapi-tests/tests.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::CompartmentOptions 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.
    {
        JSAutoCompartment ac(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 : public JS::CallbackTracer {
    void 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;
    }

  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)
{
    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.init());
    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
countWrappers(JSCompartment* comp)
{
    size_t count = 0;
    for (JSCompartment::WrapperEnum e(comp); !e.empty(); e.popFront())
        ++count;
    return count;
}

BEGIN_TEST(testDeadNurseryCCW)
{
    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(countWrappers(global1->compartment()) == 1);
    cx->gc.evictNursery();
    CHECK(countWrappers(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)
{
    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(countWrappers(global1->compartment()) == 1);
    cx->gc.evictNursery();
    CHECK(countWrappers(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)
{
    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(countWrappers(global1->compartment()) == 1);
    cx->gc.evictNursery();
    CHECK(countWrappers(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)
{
    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(countWrappers(global1->compartment()) == 1);
    cx->gc.evictNursery();
    CHECK(countWrappers(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();

    // 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::AutoObjectVector vec(cx);
    if (!vec.append(root))
        return false;

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

    // Release all roots except for the AutoObjectVector.
    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_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().isMarked());
    MOZ_ASSERT(!leafHandle->asTenured().isMarked());
    MOZ_ASSERT(!leafOwnerHandle->asTenured().isMarked());

#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().isMarked());

    // 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().isMarked());
        if (!JS_SetProperty(cx, vec[0], "leafcopy", leaf2))
            return false;
        MOZ_ASSERT(rt->gc.gcNumber() == currentGCNumber);
        MOZ_ASSERT(!leaf2.toObject().asTenured().isMarked());
    }

    // 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)