1 //===- llvm/unittest/ADT/StringMapMap.cpp - StringMap unit tests ----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/ADT/StringMap.h"
10 #include "llvm/ADT/Twine.h"
11 #include "llvm/Support/DataTypes.h"
12 #include "gtest/gtest.h"
13 #include <limits>
14 #include <tuple>
15 using namespace llvm;
16 
17 namespace {
18 
19 // Test fixture
20 class StringMapTest : public testing::Test {
21 protected:
22   StringMap<uint32_t> testMap;
23 
24   static const char testKey[];
25   static const uint32_t testValue;
26   static const char* testKeyFirst;
27   static size_t testKeyLength;
28   static const std::string testKeyStr;
29 
assertEmptyMap()30   void assertEmptyMap() {
31     // Size tests
32     EXPECT_EQ(0u, testMap.size());
33     EXPECT_TRUE(testMap.empty());
34 
35     // Iterator tests
36     EXPECT_TRUE(testMap.begin() == testMap.end());
37 
38     // Lookup tests
39     EXPECT_EQ(0u, testMap.count(testKey));
40     EXPECT_EQ(0u, testMap.count(StringRef(testKeyFirst, testKeyLength)));
41     EXPECT_EQ(0u, testMap.count(testKeyStr));
42     EXPECT_TRUE(testMap.find(testKey) == testMap.end());
43     EXPECT_TRUE(testMap.find(StringRef(testKeyFirst, testKeyLength)) ==
44                 testMap.end());
45     EXPECT_TRUE(testMap.find(testKeyStr) == testMap.end());
46   }
47 
assertSingleItemMap()48   void assertSingleItemMap() {
49     // Size tests
50     EXPECT_EQ(1u, testMap.size());
51     EXPECT_FALSE(testMap.begin() == testMap.end());
52     EXPECT_FALSE(testMap.empty());
53 
54     // Iterator tests
55     StringMap<uint32_t>::iterator it = testMap.begin();
56     EXPECT_STREQ(testKey, it->first().data());
57     EXPECT_EQ(testValue, it->second);
58     ++it;
59     EXPECT_TRUE(it == testMap.end());
60 
61     // Lookup tests
62     EXPECT_EQ(1u, testMap.count(testKey));
63     EXPECT_EQ(1u, testMap.count(StringRef(testKeyFirst, testKeyLength)));
64     EXPECT_EQ(1u, testMap.count(testKeyStr));
65     EXPECT_TRUE(testMap.find(testKey) == testMap.begin());
66     EXPECT_TRUE(testMap.find(StringRef(testKeyFirst, testKeyLength)) ==
67                 testMap.begin());
68     EXPECT_TRUE(testMap.find(testKeyStr) == testMap.begin());
69   }
70 };
71 
72 const char StringMapTest::testKey[] = "key";
73 const uint32_t StringMapTest::testValue = 1u;
74 const char* StringMapTest::testKeyFirst = testKey;
75 size_t StringMapTest::testKeyLength = sizeof(testKey) - 1;
76 const std::string StringMapTest::testKeyStr(testKey);
77 
78 struct CountCopyAndMove {
79   CountCopyAndMove() = default;
CountCopyAndMove__anon5a1fd6cf0111::CountCopyAndMove80   CountCopyAndMove(const CountCopyAndMove &) { copy = 1; }
CountCopyAndMove__anon5a1fd6cf0111::CountCopyAndMove81   CountCopyAndMove(CountCopyAndMove &&) { move = 1; }
operator =__anon5a1fd6cf0111::CountCopyAndMove82   void operator=(const CountCopyAndMove &) { ++copy; }
operator =__anon5a1fd6cf0111::CountCopyAndMove83   void operator=(CountCopyAndMove &&) { ++move; }
84   int copy = 0;
85   int move = 0;
86 };
87 
88 // Empty map tests.
TEST_F(StringMapTest,EmptyMapTest)89 TEST_F(StringMapTest, EmptyMapTest) {
90   assertEmptyMap();
91 }
92 
93 // Constant map tests.
TEST_F(StringMapTest,ConstEmptyMapTest)94 TEST_F(StringMapTest, ConstEmptyMapTest) {
95   const StringMap<uint32_t>& constTestMap = testMap;
96 
97   // Size tests
98   EXPECT_EQ(0u, constTestMap.size());
99   EXPECT_TRUE(constTestMap.empty());
100 
101   // Iterator tests
102   EXPECT_TRUE(constTestMap.begin() == constTestMap.end());
103 
104   // Lookup tests
105   EXPECT_EQ(0u, constTestMap.count(testKey));
106   EXPECT_EQ(0u, constTestMap.count(StringRef(testKeyFirst, testKeyLength)));
107   EXPECT_EQ(0u, constTestMap.count(testKeyStr));
108   EXPECT_TRUE(constTestMap.find(testKey) == constTestMap.end());
109   EXPECT_TRUE(constTestMap.find(StringRef(testKeyFirst, testKeyLength)) ==
110               constTestMap.end());
111   EXPECT_TRUE(constTestMap.find(testKeyStr) == constTestMap.end());
112 }
113 
114 // A map with a single entry.
TEST_F(StringMapTest,SingleEntryMapTest)115 TEST_F(StringMapTest, SingleEntryMapTest) {
116   testMap[testKey] = testValue;
117   assertSingleItemMap();
118 }
119 
120 // Test clear() method.
TEST_F(StringMapTest,ClearTest)121 TEST_F(StringMapTest, ClearTest) {
122   testMap[testKey] = testValue;
123   testMap.clear();
124   assertEmptyMap();
125 }
126 
127 // Test erase(iterator) method.
TEST_F(StringMapTest,EraseIteratorTest)128 TEST_F(StringMapTest, EraseIteratorTest) {
129   testMap[testKey] = testValue;
130   testMap.erase(testMap.begin());
131   assertEmptyMap();
132 }
133 
134 // Test erase(value) method.
TEST_F(StringMapTest,EraseValueTest)135 TEST_F(StringMapTest, EraseValueTest) {
136   testMap[testKey] = testValue;
137   testMap.erase(testKey);
138   assertEmptyMap();
139 }
140 
141 // Test inserting two values and erasing one.
TEST_F(StringMapTest,InsertAndEraseTest)142 TEST_F(StringMapTest, InsertAndEraseTest) {
143   testMap[testKey] = testValue;
144   testMap["otherKey"] = 2;
145   testMap.erase("otherKey");
146   assertSingleItemMap();
147 }
148 
TEST_F(StringMapTest,SmallFullMapTest)149 TEST_F(StringMapTest, SmallFullMapTest) {
150   // StringMap has a tricky corner case when the map is small (<8 buckets) and
151   // it fills up through a balanced pattern of inserts and erases. This can
152   // lead to inf-loops in some cases (PR13148) so we test it explicitly here.
153   llvm::StringMap<int> Map(2);
154 
155   Map["eins"] = 1;
156   Map["zwei"] = 2;
157   Map["drei"] = 3;
158   Map.erase("drei");
159   Map.erase("eins");
160   Map["veir"] = 4;
161   Map["funf"] = 5;
162 
163   EXPECT_EQ(3u, Map.size());
164   EXPECT_EQ(0, Map.lookup("eins"));
165   EXPECT_EQ(2, Map.lookup("zwei"));
166   EXPECT_EQ(0, Map.lookup("drei"));
167   EXPECT_EQ(4, Map.lookup("veir"));
168   EXPECT_EQ(5, Map.lookup("funf"));
169 }
170 
TEST_F(StringMapTest,CopyCtorTest)171 TEST_F(StringMapTest, CopyCtorTest) {
172   llvm::StringMap<int> Map;
173 
174   Map["eins"] = 1;
175   Map["zwei"] = 2;
176   Map["drei"] = 3;
177   Map.erase("drei");
178   Map.erase("eins");
179   Map["veir"] = 4;
180   Map["funf"] = 5;
181 
182   EXPECT_EQ(3u, Map.size());
183   EXPECT_EQ(0, Map.lookup("eins"));
184   EXPECT_EQ(2, Map.lookup("zwei"));
185   EXPECT_EQ(0, Map.lookup("drei"));
186   EXPECT_EQ(4, Map.lookup("veir"));
187   EXPECT_EQ(5, Map.lookup("funf"));
188 
189   llvm::StringMap<int> Map2(Map);
190   EXPECT_EQ(3u, Map2.size());
191   EXPECT_EQ(0, Map2.lookup("eins"));
192   EXPECT_EQ(2, Map2.lookup("zwei"));
193   EXPECT_EQ(0, Map2.lookup("drei"));
194   EXPECT_EQ(4, Map2.lookup("veir"));
195   EXPECT_EQ(5, Map2.lookup("funf"));
196 }
197 
198 // A more complex iteration test.
TEST_F(StringMapTest,IterationTest)199 TEST_F(StringMapTest, IterationTest) {
200   bool visited[100];
201 
202   // Insert 100 numbers into the map
203   for (int i = 0; i < 100; ++i) {
204     std::stringstream ss;
205     ss << "key_" << i;
206     testMap[ss.str()] = i;
207     visited[i] = false;
208   }
209 
210   // Iterate over all numbers and mark each one found.
211   for (StringMap<uint32_t>::iterator it = testMap.begin();
212       it != testMap.end(); ++it) {
213     std::stringstream ss;
214     ss << "key_" << it->second;
215     ASSERT_STREQ(ss.str().c_str(), it->first().data());
216     visited[it->second] = true;
217   }
218 
219   // Ensure every number was visited.
220   for (int i = 0; i < 100; ++i) {
221     ASSERT_TRUE(visited[i]) << "Entry #" << i << " was never visited";
222   }
223 }
224 
225 // Test StringMapEntry::Create() method.
TEST_F(StringMapTest,StringMapEntryTest)226 TEST_F(StringMapTest, StringMapEntryTest) {
227   StringMap<uint32_t>::value_type* entry =
228       StringMap<uint32_t>::value_type::Create(
229           StringRef(testKeyFirst, testKeyLength), 1u);
230   EXPECT_STREQ(testKey, entry->first().data());
231   EXPECT_EQ(1u, entry->second);
232   free(entry);
233 }
234 
235 // Test insert() method.
TEST_F(StringMapTest,InsertTest)236 TEST_F(StringMapTest, InsertTest) {
237   SCOPED_TRACE("InsertTest");
238   testMap.insert(
239       StringMap<uint32_t>::value_type::Create(
240           StringRef(testKeyFirst, testKeyLength),
241           testMap.getAllocator(), 1u));
242   assertSingleItemMap();
243 }
244 
245 // Test insert(pair<K, V>) method
TEST_F(StringMapTest,InsertPairTest)246 TEST_F(StringMapTest, InsertPairTest) {
247   bool Inserted;
248   StringMap<uint32_t>::iterator NewIt;
249   std::tie(NewIt, Inserted) =
250       testMap.insert(std::make_pair(testKeyFirst, testValue));
251   EXPECT_EQ(1u, testMap.size());
252   EXPECT_EQ(testValue, testMap[testKeyFirst]);
253   EXPECT_EQ(testKeyFirst, NewIt->first());
254   EXPECT_EQ(testValue, NewIt->second);
255   EXPECT_TRUE(Inserted);
256 
257   StringMap<uint32_t>::iterator ExistingIt;
258   std::tie(ExistingIt, Inserted) =
259       testMap.insert(std::make_pair(testKeyFirst, testValue + 1));
260   EXPECT_EQ(1u, testMap.size());
261   EXPECT_EQ(testValue, testMap[testKeyFirst]);
262   EXPECT_FALSE(Inserted);
263   EXPECT_EQ(NewIt, ExistingIt);
264 }
265 
266 // Test insert(pair<K, V>) method when rehashing occurs
TEST_F(StringMapTest,InsertRehashingPairTest)267 TEST_F(StringMapTest, InsertRehashingPairTest) {
268   // Check that the correct iterator is returned when the inserted element is
269   // moved to a different bucket during internal rehashing. This depends on
270   // the particular key, and the implementation of StringMap and HashString.
271   // Changes to those might result in this test not actually checking that.
272   StringMap<uint32_t> t(0);
273   EXPECT_EQ(0u, t.getNumBuckets());
274 
275   StringMap<uint32_t>::iterator It =
276     t.insert(std::make_pair("abcdef", 42)).first;
277   EXPECT_EQ(16u, t.getNumBuckets());
278   EXPECT_EQ("abcdef", It->first());
279   EXPECT_EQ(42u, It->second);
280 }
281 
TEST_F(StringMapTest,InsertOrAssignTest)282 TEST_F(StringMapTest, InsertOrAssignTest) {
283   struct A : CountCopyAndMove {
284     A(int v) : v(v) {}
285     int v;
286   };
287   StringMap<A> t(0);
288 
289   auto try1 = t.insert_or_assign("A", A(1));
290   EXPECT_TRUE(try1.second);
291   EXPECT_EQ(1, try1.first->second.v);
292   EXPECT_EQ(1, try1.first->second.move);
293 
294   auto try2 = t.insert_or_assign("A", A(2));
295   EXPECT_FALSE(try2.second);
296   EXPECT_EQ(2, try2.first->second.v);
297   EXPECT_EQ(2, try1.first->second.move);
298 
299   EXPECT_EQ(try1.first, try2.first);
300   EXPECT_EQ(0, try1.first->second.copy);
301 }
302 
TEST_F(StringMapTest,IterMapKeys)303 TEST_F(StringMapTest, IterMapKeys) {
304   StringMap<int> Map;
305   Map["A"] = 1;
306   Map["B"] = 2;
307   Map["C"] = 3;
308   Map["D"] = 3;
309 
310   auto Keys = to_vector<4>(Map.keys());
311   llvm::sort(Keys);
312 
313   SmallVector<StringRef, 4> Expected = {"A", "B", "C", "D"};
314   EXPECT_EQ(Expected, Keys);
315 }
316 
317 // Create a non-default constructable value
318 struct StringMapTestStruct {
StringMapTestStruct__anon5a1fd6cf0111::StringMapTestStruct319   StringMapTestStruct(int i) : i(i) {}
320   StringMapTestStruct() = delete;
321   int i;
322 };
323 
TEST_F(StringMapTest,NonDefaultConstructable)324 TEST_F(StringMapTest, NonDefaultConstructable) {
325   StringMap<StringMapTestStruct> t;
326   t.insert(std::make_pair("Test", StringMapTestStruct(123)));
327   StringMap<StringMapTestStruct>::iterator iter = t.find("Test");
328   ASSERT_NE(iter, t.end());
329   ASSERT_EQ(iter->second.i, 123);
330 }
331 
332 struct Immovable {
Immovable__anon5a1fd6cf0111::Immovable333   Immovable() {}
334   Immovable(Immovable&&) = delete; // will disable the other special members
335 };
336 
337 struct MoveOnly {
338   int i;
MoveOnly__anon5a1fd6cf0111::MoveOnly339   MoveOnly(int i) : i(i) {}
MoveOnly__anon5a1fd6cf0111::MoveOnly340   MoveOnly(const Immovable&) : i(0) {}
MoveOnly__anon5a1fd6cf0111::MoveOnly341   MoveOnly(MoveOnly &&RHS) : i(RHS.i) {}
operator =__anon5a1fd6cf0111::MoveOnly342   MoveOnly &operator=(MoveOnly &&RHS) {
343     i = RHS.i;
344     return *this;
345   }
346 
347 private:
348   MoveOnly(const MoveOnly &) = delete;
349   MoveOnly &operator=(const MoveOnly &) = delete;
350 };
351 
TEST_F(StringMapTest,MoveOnly)352 TEST_F(StringMapTest, MoveOnly) {
353   StringMap<MoveOnly> t;
354   t.insert(std::make_pair("Test", MoveOnly(42)));
355   StringRef Key = "Test";
356   StringMapEntry<MoveOnly>::Create(Key, MoveOnly(42))
357       ->Destroy();
358 }
359 
TEST_F(StringMapTest,CtorArg)360 TEST_F(StringMapTest, CtorArg) {
361   StringRef Key = "Test";
362   StringMapEntry<MoveOnly>::Create(Key, Immovable())
363       ->Destroy();
364 }
365 
TEST_F(StringMapTest,MoveConstruct)366 TEST_F(StringMapTest, MoveConstruct) {
367   StringMap<int> A;
368   A["x"] = 42;
369   StringMap<int> B = std::move(A);
370   ASSERT_EQ(A.size(), 0u);
371   ASSERT_EQ(B.size(), 1u);
372   ASSERT_EQ(B["x"], 42);
373   ASSERT_EQ(B.count("y"), 0u);
374 }
375 
TEST_F(StringMapTest,MoveAssignment)376 TEST_F(StringMapTest, MoveAssignment) {
377   StringMap<int> A;
378   A["x"] = 42;
379   StringMap<int> B;
380   B["y"] = 117;
381   A = std::move(B);
382   ASSERT_EQ(A.size(), 1u);
383   ASSERT_EQ(B.size(), 0u);
384   ASSERT_EQ(A["y"], 117);
385   ASSERT_EQ(B.count("x"), 0u);
386 }
387 
388 struct Countable {
389   int &InstanceCount;
390   int Number;
Countable__anon5a1fd6cf0111::Countable391   Countable(int Number, int &InstanceCount)
392       : InstanceCount(InstanceCount), Number(Number) {
393     ++InstanceCount;
394   }
Countable__anon5a1fd6cf0111::Countable395   Countable(Countable &&C) : InstanceCount(C.InstanceCount), Number(C.Number) {
396     ++InstanceCount;
397     C.Number = -1;
398   }
Countable__anon5a1fd6cf0111::Countable399   Countable(const Countable &C)
400       : InstanceCount(C.InstanceCount), Number(C.Number) {
401     ++InstanceCount;
402   }
operator =__anon5a1fd6cf0111::Countable403   Countable &operator=(Countable C) {
404     Number = C.Number;
405     return *this;
406   }
~Countable__anon5a1fd6cf0111::Countable407   ~Countable() { --InstanceCount; }
408 };
409 
TEST_F(StringMapTest,MoveDtor)410 TEST_F(StringMapTest, MoveDtor) {
411   int InstanceCount = 0;
412   StringMap<Countable> A;
413   A.insert(std::make_pair("x", Countable(42, InstanceCount)));
414   ASSERT_EQ(InstanceCount, 1);
415   auto I = A.find("x");
416   ASSERT_NE(I, A.end());
417   ASSERT_EQ(I->second.Number, 42);
418 
419   StringMap<Countable> B;
420   B = std::move(A);
421   ASSERT_EQ(InstanceCount, 1);
422   ASSERT_TRUE(A.empty());
423   I = B.find("x");
424   ASSERT_NE(I, B.end());
425   ASSERT_EQ(I->second.Number, 42);
426 
427   B = StringMap<Countable>();
428   ASSERT_EQ(InstanceCount, 0);
429   ASSERT_TRUE(B.empty());
430 }
431 
432 namespace {
433 // Simple class that counts how many moves and copy happens when growing a map
434 struct CountCtorCopyAndMove {
435   static unsigned Ctor;
436   static unsigned Move;
437   static unsigned Copy;
438   int Data = 0;
CountCtorCopyAndMove__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove439   CountCtorCopyAndMove(int Data) : Data(Data) { Ctor++; }
CountCtorCopyAndMove__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove440   CountCtorCopyAndMove() { Ctor++; }
441 
CountCtorCopyAndMove__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove442   CountCtorCopyAndMove(const CountCtorCopyAndMove &) { Copy++; }
operator =__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove443   CountCtorCopyAndMove &operator=(const CountCtorCopyAndMove &) {
444     Copy++;
445     return *this;
446   }
CountCtorCopyAndMove__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove447   CountCtorCopyAndMove(CountCtorCopyAndMove &&) { Move++; }
operator =__anon5a1fd6cf0111::__anon5a1fd6cf0211::CountCtorCopyAndMove448   CountCtorCopyAndMove &operator=(const CountCtorCopyAndMove &&) {
449     Move++;
450     return *this;
451   }
452 };
453 unsigned CountCtorCopyAndMove::Copy = 0;
454 unsigned CountCtorCopyAndMove::Move = 0;
455 unsigned CountCtorCopyAndMove::Ctor = 0;
456 
457 } // anonymous namespace
458 
459 // Make sure creating the map with an initial size of N actually gives us enough
460 // buckets to insert N items without increasing allocation size.
TEST(StringMapCustomTest,InitialSizeTest)461 TEST(StringMapCustomTest, InitialSizeTest) {
462   // 1 is an "edge value", 32 is an arbitrary power of two, and 67 is an
463   // arbitrary prime, picked without any good reason.
464   for (auto Size : {1, 32, 67}) {
465     StringMap<CountCtorCopyAndMove> Map(Size);
466     auto NumBuckets = Map.getNumBuckets();
467     CountCtorCopyAndMove::Move = 0;
468     CountCtorCopyAndMove::Copy = 0;
469     for (int i = 0; i < Size; ++i)
470       Map.insert(std::pair<std::string, CountCtorCopyAndMove>(
471           std::piecewise_construct, std::forward_as_tuple(Twine(i).str()),
472           std::forward_as_tuple(i)));
473     // After the initial move, the map will move the Elts in the Entry.
474     EXPECT_EQ((unsigned)Size * 2, CountCtorCopyAndMove::Move);
475     // We copy once the pair from the Elts vector
476     EXPECT_EQ(0u, CountCtorCopyAndMove::Copy);
477     // Check that the map didn't grow
478     EXPECT_EQ(Map.getNumBuckets(), NumBuckets);
479   }
480 }
481 
TEST(StringMapCustomTest,BracketOperatorCtor)482 TEST(StringMapCustomTest, BracketOperatorCtor) {
483   StringMap<CountCtorCopyAndMove> Map;
484   CountCtorCopyAndMove::Ctor = 0;
485   Map["abcd"];
486   EXPECT_EQ(1u, CountCtorCopyAndMove::Ctor);
487   // Test that operator[] does not create a value when it is already in the map
488   CountCtorCopyAndMove::Ctor = 0;
489   Map["abcd"];
490   EXPECT_EQ(0u, CountCtorCopyAndMove::Ctor);
491 }
492 
493 namespace {
494 struct NonMoveableNonCopyableType {
495   int Data = 0;
496   NonMoveableNonCopyableType() = default;
NonMoveableNonCopyableType__anon5a1fd6cf0111::__anon5a1fd6cf0311::NonMoveableNonCopyableType497   NonMoveableNonCopyableType(int Data) : Data(Data) {}
498   NonMoveableNonCopyableType(const NonMoveableNonCopyableType &) = delete;
499   NonMoveableNonCopyableType(NonMoveableNonCopyableType &&) = delete;
500 };
501 }
502 
503 // Test that we can "emplace" an element in the map without involving map/move
TEST(StringMapCustomTest,EmplaceTest)504 TEST(StringMapCustomTest, EmplaceTest) {
505   StringMap<NonMoveableNonCopyableType> Map;
506   Map.try_emplace("abcd", 42);
507   EXPECT_EQ(1u, Map.count("abcd"));
508   EXPECT_EQ(42, Map["abcd"].Data);
509 }
510 
511 // Test that StringMapEntryBase can handle size_t wide sizes.
TEST(StringMapCustomTest,StringMapEntryBaseSize)512 TEST(StringMapCustomTest, StringMapEntryBaseSize) {
513   size_t LargeValue;
514 
515   // Test that the entry can represent max-unsigned.
516   if (sizeof(size_t) <= sizeof(unsigned))
517     LargeValue = std::numeric_limits<unsigned>::max();
518   else
519     LargeValue = std::numeric_limits<unsigned>::max() + 1ULL;
520   StringMapEntryBase LargeBase(LargeValue);
521   EXPECT_EQ(LargeValue, LargeBase.getKeyLength());
522 
523   // Test that the entry can hold at least max size_t.
524   LargeValue = std::numeric_limits<size_t>::max();
525   StringMapEntryBase LargerBase(LargeValue);
526   LargeValue = std::numeric_limits<size_t>::max();
527   EXPECT_EQ(LargeValue, LargerBase.getKeyLength());
528 }
529 
530 // Test that StringMapEntry can handle size_t wide sizes.
TEST(StringMapCustomTest,StringMapEntrySize)531 TEST(StringMapCustomTest, StringMapEntrySize) {
532   size_t LargeValue;
533 
534   // Test that the entry can represent max-unsigned.
535   if (sizeof(size_t) <= sizeof(unsigned))
536     LargeValue = std::numeric_limits<unsigned>::max();
537   else
538     LargeValue = std::numeric_limits<unsigned>::max() + 1ULL;
539   StringMapEntry<int> LargeEntry(LargeValue);
540   StringRef Key = LargeEntry.getKey();
541   EXPECT_EQ(LargeValue, Key.size());
542 
543   // Test that the entry can hold at least max size_t.
544   LargeValue = std::numeric_limits<size_t>::max();
545   StringMapEntry<int> LargerEntry(LargeValue);
546   Key = LargerEntry.getKey();
547   EXPECT_EQ(LargeValue, Key.size());
548 }
549 
550 } // end anonymous namespace
551