summaryrefslogtreecommitdiff
path: root/unittests/ExecutionEngine/Orc/CoreAPIsTest.cpp
blob: 0a87ed08edf6912e587e9e5b3e1ad6bb82853d4a (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
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
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
//===----------- CoreAPIsTest.cpp - Unit tests for Core ORC APIs ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "OrcTestCommon.h"
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "gtest/gtest.h"

#include <set>
#include <thread>

using namespace llvm;
using namespace llvm::orc;

namespace {

class SimpleMaterializationUnit : public MaterializationUnit {
public:
  using GetSymbolsFunction = std::function<SymbolFlagsMap()>;
  using MaterializeFunction = std::function<Error(VSO &)>;
  using DiscardFunction = std::function<void(VSO &, SymbolStringPtr)>;
  using DestructorFunction = std::function<void()>;

  SimpleMaterializationUnit(
      GetSymbolsFunction GetSymbols, MaterializeFunction Materialize,
      DiscardFunction Discard,
      DestructorFunction Destructor = DestructorFunction())
      : GetSymbols(std::move(GetSymbols)), Materialize(std::move(Materialize)),
        Discard(std::move(Discard)), Destructor(std::move(Destructor)) {}

  ~SimpleMaterializationUnit() override {
    if (Destructor)
      Destructor();
  }

  SymbolFlagsMap getSymbols() override { return GetSymbols(); }

  Error materialize(VSO &V) override { return Materialize(V); }

  void discard(VSO &V, SymbolStringPtr Name) override {
    Discard(V, std::move(Name));
  }

private:
  GetSymbolsFunction GetSymbols;
  MaterializeFunction Materialize;
  DiscardFunction Discard;
  DestructorFunction Destructor;
};

TEST(CoreAPIsTest, AsynchronousSymbolQuerySuccessfulResolutionOnly) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  constexpr JITTargetAddress FakeAddr = 0xdeadbeef;
  SymbolNameSet Names({Foo});

  bool OnResolutionRun = false;
  bool OnReadyRun = false;
  auto OnResolution = [&](Expected<SymbolMap> Result) {
    EXPECT_TRUE(!!Result) << "Resolution unexpectedly returned error";
    auto I = Result->find(Foo);
    EXPECT_NE(I, Result->end()) << "Could not find symbol definition";
    EXPECT_EQ(I->second.getAddress(), FakeAddr)
        << "Resolution returned incorrect result";
    OnResolutionRun = true;
  };
  auto OnReady = [&](Error Err) {
    cantFail(std::move(Err));
    OnReadyRun = true;
  };

  AsynchronousSymbolQuery Q(Names, OnResolution, OnReady);

  Q.resolve(Foo, JITEvaluatedSymbol(FakeAddr, JITSymbolFlags::Exported));

  EXPECT_TRUE(OnResolutionRun) << "OnResolutionCallback was not run";
  EXPECT_FALSE(OnReadyRun) << "OnReady unexpectedly run";
}

TEST(CoreAPIsTest, AsynchronousSymbolQueryResolutionErrorOnly) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  SymbolNameSet Names({Foo});

  bool OnResolutionRun = false;
  bool OnReadyRun = false;

  auto OnResolution = [&](Expected<SymbolMap> Result) {
    EXPECT_FALSE(!!Result) << "Resolution unexpectedly returned success";
    auto Msg = toString(Result.takeError());
    EXPECT_EQ(Msg, "xyz") << "Resolution returned incorrect result";
    OnResolutionRun = true;
  };
  auto OnReady = [&](Error Err) {
    cantFail(std::move(Err));
    OnReadyRun = true;
  };

  AsynchronousSymbolQuery Q(Names, OnResolution, OnReady);

  Q.notifyFailed(make_error<StringError>("xyz", inconvertibleErrorCode()));

  EXPECT_TRUE(OnResolutionRun) << "OnResolutionCallback was not run";
  EXPECT_FALSE(OnReadyRun) << "OnReady unexpectedly run";
}

TEST(CoreAPIsTest, SimpleAsynchronousSymbolQueryAgainstVSO) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  constexpr JITTargetAddress FakeAddr = 0xdeadbeef;
  SymbolNameSet Names({Foo});

  bool OnResolutionRun = false;
  bool OnReadyRun = false;

  auto OnResolution = [&](Expected<SymbolMap> Result) {
    EXPECT_TRUE(!!Result) << "Query unexpectedly returned error";
    auto I = Result->find(Foo);
    EXPECT_NE(I, Result->end()) << "Could not find symbol definition";
    EXPECT_EQ(I->second.getAddress(), FakeAddr)
        << "Resolution returned incorrect result";
    OnResolutionRun = true;
  };

  auto OnReady = [&](Error Err) {
    cantFail(std::move(Err));
    OnReadyRun = true;
  };

  auto Q =
      std::make_shared<AsynchronousSymbolQuery>(Names, OnResolution, OnReady);
  VSO V;

  SymbolMap Defs;
  Defs[Foo] = JITEvaluatedSymbol(FakeAddr, JITSymbolFlags::Exported);
  cantFail(V.define(std::move(Defs)));
  V.lookup(Q, Names);

  EXPECT_TRUE(OnResolutionRun) << "OnResolutionCallback was not run";
  EXPECT_TRUE(OnReadyRun) << "OnReady was not run";
}

TEST(CoreAPIsTest, LookupFlagsTest) {

  // Test that lookupFlags works on a predefined symbol, and does not trigger
  // materialization of a lazy symbol.

  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");
  auto Baz = SP.intern("baz");

  JITSymbolFlags FooFlags = JITSymbolFlags::Exported;
  JITSymbolFlags BarFlags = static_cast<JITSymbolFlags::FlagNames>(
      JITSymbolFlags::Exported | JITSymbolFlags::Weak);

  VSO V;

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap({{Bar, BarFlags}});
      },
      [](VSO &V) -> Error {
        llvm_unreachable("Symbol materialized on flags lookup");
      },
      [](VSO &V, SymbolStringPtr Name) -> Error {
        llvm_unreachable("Symbol finalized on flags lookup");
      });

  SymbolMap InitialDefs;
  InitialDefs[Foo] = JITEvaluatedSymbol(0xdeadbeef, FooFlags);
  cantFail(V.define(std::move(InitialDefs)));

  cantFail(V.defineLazy(std::move(MU)));

  SymbolNameSet Names({Foo, Bar, Baz});

  SymbolFlagsMap SymbolFlags;
  auto SymbolsNotFound = V.lookupFlags(SymbolFlags, Names);

  EXPECT_EQ(SymbolsNotFound.size(), 1U) << "Expected one not-found symbol";
  EXPECT_EQ(SymbolsNotFound.count(Baz), 1U) << "Expected Baz to be not-found";
  EXPECT_EQ(SymbolFlags.size(), 2U)
      << "Returned symbol flags contains unexpected results";
  EXPECT_EQ(SymbolFlags.count(Foo), 1U) << "Missing lookupFlags result for Foo";
  EXPECT_EQ(SymbolFlags[Foo], FooFlags) << "Incorrect flags returned for Foo";
  EXPECT_EQ(SymbolFlags.count(Bar), 1U)
      << "Missing  lookupFlags result for Bar";
  EXPECT_EQ(SymbolFlags[Bar], BarFlags) << "Incorrect flags returned for Bar";
}

TEST(CoreAPIsTest, DropMaterializerWhenEmpty) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");

  bool DestructorRun = false;

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap(
            {{Foo, JITSymbolFlags::Weak}, {Bar, JITSymbolFlags::Weak}});
      },
      [](VSO &V) -> Error {
        llvm_unreachable("Unexpected call to materialize");
      },
      [&](VSO &V, SymbolStringPtr Name) {
        EXPECT_TRUE(Name == Foo || Name == Bar)
            << "Discard of unexpected symbol?";
      },
      [&]() { DestructorRun = true; });

  VSO V;

  cantFail(V.defineLazy(std::move(MU)));

  auto FooSym = JITEvaluatedSymbol(1, JITSymbolFlags::Exported);
  auto BarSym = JITEvaluatedSymbol(2, JITSymbolFlags::Exported);
  cantFail(V.define(SymbolMap({{Foo, FooSym}})));

  EXPECT_FALSE(DestructorRun)
      << "MaterializationUnit should not have been destroyed yet";

  cantFail(V.define(SymbolMap({{Bar, BarSym}})));

  EXPECT_TRUE(DestructorRun)
      << "MaterializationUnit should have been destroyed";
}

TEST(CoreAPIsTest, AddAndMaterializeLazySymbol) {

  constexpr JITTargetAddress FakeFooAddr = 0xdeadbeef;
  constexpr JITTargetAddress FakeBarAddr = 0xcafef00d;

  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");

  bool FooMaterialized = false;
  bool BarDiscarded = false;

  VSO V;

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap(
            {{Foo, JITSymbolFlags::Exported},
             {Bar, static_cast<JITSymbolFlags::FlagNames>(
                       JITSymbolFlags::Exported | JITSymbolFlags::Weak)}});
      },
      [&](VSO &V) {
        assert(BarDiscarded && "Bar should have been discarded by this point");
        SymbolMap SymbolsToResolve;
        SymbolsToResolve[Foo] =
            JITEvaluatedSymbol(FakeFooAddr, JITSymbolFlags::Exported);
        V.resolve(std::move(SymbolsToResolve));
        SymbolNameSet SymbolsToFinalize;
        SymbolsToFinalize.insert(Foo);
        V.finalize(SymbolsToFinalize);
        FooMaterialized = true;
        return Error::success();
      },
      [&](VSO &V, SymbolStringPtr Name) {
        EXPECT_EQ(Name, Bar) << "Expected Name to be Bar";
        BarDiscarded = true;
      });

  cantFail(V.defineLazy(std::move(MU)));

  SymbolMap BarOverride;
  BarOverride[Bar] = JITEvaluatedSymbol(FakeBarAddr, JITSymbolFlags::Exported);
  cantFail(V.define(std::move(BarOverride)));

  SymbolNameSet Names({Foo});

  bool OnResolutionRun = false;
  bool OnReadyRun = false;

  auto OnResolution = [&](Expected<SymbolMap> Result) {
    EXPECT_TRUE(!!Result) << "Resolution unexpectedly returned error";
    auto I = Result->find(Foo);
    EXPECT_NE(I, Result->end()) << "Could not find symbol definition";
    EXPECT_EQ(I->second.getAddress(), FakeFooAddr)
        << "Resolution returned incorrect result";
    OnResolutionRun = true;
  };

  auto OnReady = [&](Error Err) {
    cantFail(std::move(Err));
    OnReadyRun = true;
  };

  auto Q =
      std::make_shared<AsynchronousSymbolQuery>(Names, OnResolution, OnReady);

  auto LR = V.lookup(std::move(Q), Names);

  for (auto &SWKV : LR.MaterializationUnits)
    cantFail(SWKV->materialize(V));

  EXPECT_TRUE(LR.UnresolvedSymbols.empty()) << "Could not find Foo in dylib";
  EXPECT_TRUE(FooMaterialized) << "Foo was not materialized";
  EXPECT_TRUE(BarDiscarded) << "Bar was not discarded";
  EXPECT_TRUE(OnResolutionRun) << "OnResolutionCallback was not run";
  EXPECT_TRUE(OnReadyRun) << "OnReady was not run";
}

TEST(CoreAPIsTest, FailResolution) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");

  SymbolNameSet Names({Foo, Bar});

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap(
            {{Foo, JITSymbolFlags::Weak}, {Bar, JITSymbolFlags::Weak}});
      },
      [&](VSO &V) -> Error {
        V.notifyResolutionFailed(Names);
        return Error::success();
      },
      [&](VSO &V, SymbolStringPtr Name) {
        llvm_unreachable("Unexpected call to discard");
      });

  VSO V;

  cantFail(V.defineLazy(std::move(MU)));

  auto OnResolution = [&](Expected<SymbolMap> Result) {
    handleAllErrors(Result.takeError(),
                    [&](FailedToResolve &F) {
                      EXPECT_EQ(F.getSymbols(), Names)
                          << "Expected to fail on symbols in Names";
                    },
                    [](ErrorInfoBase &EIB) {
                      std::string ErrMsg;
                      {
                        raw_string_ostream ErrOut(ErrMsg);
                        EIB.log(ErrOut);
                      }
                      ADD_FAILURE()
                          << "Expected a FailedToResolve error. Got:\n"
                          << ErrMsg;
                    });
  };

  auto OnReady = [](Error Err) {
    cantFail(std::move(Err));
    ADD_FAILURE() << "OnReady should never be called";
  };

  auto Q =
      std::make_shared<AsynchronousSymbolQuery>(Names, OnResolution, OnReady);

  auto LR = V.lookup(std::move(Q), Names);
  for (auto &SWKV : LR.MaterializationUnits)
    cantFail(SWKV->materialize(V));
}

TEST(CoreAPIsTest, FailFinalization) {
  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");

  SymbolNameSet Names({Foo, Bar});

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap(
            {{Foo, JITSymbolFlags::Weak}, {Bar, JITSymbolFlags::Weak}});
      },
      [&](VSO &V) -> Error {
        constexpr JITTargetAddress FakeFooAddr = 0xdeadbeef;
        constexpr JITTargetAddress FakeBarAddr = 0xcafef00d;

        auto FooSym = JITEvaluatedSymbol(FakeFooAddr, JITSymbolFlags::Exported);
        auto BarSym = JITEvaluatedSymbol(FakeBarAddr, JITSymbolFlags::Exported);
        V.resolve(SymbolMap({{Foo, FooSym}, {Bar, BarSym}}));
        V.notifyFinalizationFailed(Names);
        return Error::success();
      },
      [&](VSO &V, SymbolStringPtr Name) {
        llvm_unreachable("Unexpected call to discard");
      });

  VSO V;

  cantFail(V.defineLazy(std::move(MU)));

  auto OnResolution = [](Expected<SymbolMap> Result) {
    cantFail(std::move(Result));
  };

  auto OnReady = [&](Error Err) {
    handleAllErrors(std::move(Err),
                    [&](FailedToFinalize &F) {
                      EXPECT_EQ(F.getSymbols(), Names)
                          << "Expected to fail on symbols in Names";
                    },
                    [](ErrorInfoBase &EIB) {
                      std::string ErrMsg;
                      {
                        raw_string_ostream ErrOut(ErrMsg);
                        EIB.log(ErrOut);
                      }
                      ADD_FAILURE()
                          << "Expected a FailedToFinalize error. Got:\n"
                          << ErrMsg;
                    });
  };

  auto Q =
      std::make_shared<AsynchronousSymbolQuery>(Names, OnResolution, OnReady);

  auto LR = V.lookup(std::move(Q), Names);
  for (auto &SWKV : LR.MaterializationUnits)
    cantFail(SWKV->materialize(V));
}

TEST(CoreAPIsTest, TestLambdaSymbolResolver) {
  JITEvaluatedSymbol FooSym(0xdeadbeef, JITSymbolFlags::Exported);
  JITEvaluatedSymbol BarSym(0xcafef00d, JITSymbolFlags::Exported);

  SymbolStringPool SP;
  auto Foo = SP.intern("foo");
  auto Bar = SP.intern("bar");
  auto Baz = SP.intern("baz");

  VSO V;
  cantFail(V.define({{Foo, FooSym}, {Bar, BarSym}}));

  auto Resolver = createSymbolResolver(
      [&](SymbolFlagsMap &SymbolFlags, const SymbolNameSet &Symbols) {
        return V.lookupFlags(SymbolFlags, Symbols);
      },
      [&](std::shared_ptr<AsynchronousSymbolQuery> Q, SymbolNameSet Symbols) {
        auto LR = V.lookup(std::move(Q), Symbols);
        assert(LR.MaterializationUnits.empty() &&
               "Test generated unexpected materialization work?");
        return std::move(LR.UnresolvedSymbols);
      });

  SymbolNameSet Symbols({Foo, Bar, Baz});

  SymbolFlagsMap SymbolFlags;
  SymbolNameSet SymbolsNotFound = Resolver->lookupFlags(SymbolFlags, Symbols);

  EXPECT_EQ(SymbolFlags.size(), 2U)
      << "lookupFlags returned the wrong number of results";
  EXPECT_EQ(SymbolFlags.count(Foo), 1U) << "Missing lookupFlags result for foo";
  EXPECT_EQ(SymbolFlags.count(Bar), 1U) << "Missing lookupFlags result for bar";
  EXPECT_EQ(SymbolFlags[Foo], FooSym.getFlags())
      << "Incorrect lookupFlags result for Foo";
  EXPECT_EQ(SymbolFlags[Bar], BarSym.getFlags())
      << "Incorrect lookupFlags result for Bar";
  EXPECT_EQ(SymbolsNotFound.size(), 1U)
      << "Expected one symbol not found in lookupFlags";
  EXPECT_EQ(SymbolsNotFound.count(Baz), 1U)
      << "Expected baz not to be found in lookupFlags";

  bool OnResolvedRun = false;

  auto OnResolved = [&](Expected<SymbolMap> Result) {
    OnResolvedRun = true;
    EXPECT_TRUE(!!Result) << "Unexpected error";
    EXPECT_EQ(Result->size(), 2U) << "Unexpected number of resolved symbols";
    EXPECT_EQ(Result->count(Foo), 1U) << "Missing lookup result for foo";
    EXPECT_EQ(Result->count(Bar), 1U) << "Missing lookup result for bar";
    EXPECT_EQ((*Result)[Foo].getAddress(), FooSym.getAddress())
        << "Incorrect address for foo";
    EXPECT_EQ((*Result)[Bar].getAddress(), BarSym.getAddress())
        << "Incorrect address for bar";
  };
  auto OnReady = [&](Error Err) {
    EXPECT_FALSE(!!Err) << "Finalization should never fail in this test";
  };

  auto Q = std::make_shared<AsynchronousSymbolQuery>(SymbolNameSet({Foo, Bar}),
                                                     OnResolved, OnReady);
  auto Unresolved = Resolver->lookup(std::move(Q), Symbols);

  EXPECT_EQ(Unresolved.size(), 1U) << "Expected one unresolved symbol";
  EXPECT_EQ(Unresolved.count(Baz), 1U) << "Expected baz to not be resolved";
  EXPECT_TRUE(OnResolvedRun) << "OnResolved was never run";
}

TEST(CoreAPIsTest, TestLookupWithUnthreadedMaterialization) {
  constexpr JITTargetAddress FakeFooAddr = 0xdeadbeef;
  JITEvaluatedSymbol FooSym(FakeFooAddr, JITSymbolFlags::Exported);

  ExecutionSession ES(std::make_shared<SymbolStringPool>());
  auto Foo = ES.getSymbolStringPool().intern("foo");

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap({{Foo, JITSymbolFlags::Exported}});
      },
      [&](VSO &V) -> Error {
        V.resolve({{Foo, FooSym}});
        V.finalize({Foo});
        return Error::success();
      },
      [](VSO &V, SymbolStringPtr Name) -> Error {
        llvm_unreachable("Not expecting finalization");
      });

  VSO V;

  cantFail(V.defineLazy(std::move(MU)));

  auto FooLookupResult =
      cantFail(lookup({&V}, Foo, MaterializeOnCurrentThread(ES)));

  EXPECT_EQ(FooLookupResult.getAddress(), FooSym.getAddress())
      << "lookup returned an incorrect address";
  EXPECT_EQ(FooLookupResult.getFlags(), FooSym.getFlags())
      << "lookup returned incorrect flags";
}

TEST(CoreAPIsTest, TestLookupWithThreadedMaterialization) {
#if LLVM_ENABLE_THREADS
  constexpr JITTargetAddress FakeFooAddr = 0xdeadbeef;
  JITEvaluatedSymbol FooSym(FakeFooAddr, JITSymbolFlags::Exported);

  ExecutionSession ES(std::make_shared<SymbolStringPool>());
  auto Foo = ES.getSymbolStringPool().intern("foo");

  auto MU = llvm::make_unique<SimpleMaterializationUnit>(
      [=]() {
        return SymbolFlagsMap({{Foo, JITSymbolFlags::Exported}});
      },
      [&](VSO &V) -> Error {
        V.resolve({{Foo, FooSym}});
        V.finalize({Foo});
        return Error::success();
      },
      [](VSO &V, SymbolStringPtr Name) -> Error {
        llvm_unreachable("Not expecting finalization");
      });

  VSO V;

  cantFail(V.defineLazy(std::move(MU)));

  std::thread MaterializationThread;
  auto MaterializeOnNewThread = [&](VSO &V,
                                    std::unique_ptr<MaterializationUnit> MU) {
    // FIXME: Use move capture once we move to C++14.
    std::shared_ptr<MaterializationUnit> SharedMU = std::move(MU);
    MaterializationThread = std::thread([&ES, &V, SharedMU]() {
      if (auto Err = SharedMU->materialize(V))
        ES.reportError(std::move(Err));
    });
  };

  auto FooLookupResult =
    cantFail(lookup({&V}, Foo, MaterializeOnNewThread));

  EXPECT_EQ(FooLookupResult.getAddress(), FooSym.getAddress())
      << "lookup returned an incorrect address";
  EXPECT_EQ(FooLookupResult.getFlags(), FooSym.getFlags())
      << "lookup returned incorrect flags";
  MaterializationThread.join();
#endif
}

} // namespace