[compiler-rt] [scudo] Added test fixture for cache tests. (PR #102230)

[Christopher Ferris via llvm-commits]

================
@@ -265,3 +265,101 @@ TEST_F(MapAllocatorWithReleaseTest, SecondaryThreadsRace) {
   Allocator->getStats(&Str);
   Str.output();
 }
+
+struct MapAllocatorCacheTest : public Test {
+  static constexpr scudo::u32 UnmappedMarker = 0xDEADBEEF;
+
+  static void testUnmapCallback(scudo::MemMapT &MemMap) {
+    scudo::u32 *Ptr = reinterpret_cast<scudo::u32 *>(MemMap.getBase());
+    *Ptr = UnmappedMarker;
+  }
+
+  using SecondaryConfig = scudo::SecondaryConfig<TestConfig>;
+  using CacheConfig = SecondaryConfig::CacheConfig;
+  using CacheT = scudo::MapAllocatorCache<CacheConfig, testUnmapCallback>;
+
+  std::unique_ptr<CacheT> Cache = std::make_unique<CacheT>();
+
+  const scudo::uptr PageSize = scudo::getPageSizeCached();
+  // The current test allocation size is set to the minimum size
+  // needed for the scudo allocator to fall back to the secondary allocator
+  static constexpr scudo::uptr TestAllocSize =
+      CacheConfig::getDefaultMaxEntrySize();
+
+  scudo::Options Options = getOptionsForConfig<SecondaryConfig>();
+
+  void SetUp() override { Cache->init(/*ReleaseToOsInterval=*/-1); }
+
+  void TearDown() override { Cache->unmapTestOnly(); }
+
+  scudo::MemMapT allocate(scudo::uptr Size) {
+    scudo::uptr MapSize = scudo::roundUp(Size, PageSize);
+    scudo::ReservedMemoryT ReservedMemory;
+    CHECK(ReservedMemory.create(0U, MapSize, nullptr, MAP_ALLOWNOMEM));
+
+    scudo::MemMapT MemMap = ReservedMemory.dispatch(
+        ReservedMemory.getBase(), ReservedMemory.getCapacity());
+    MemMap.remap(MemMap.getBase(), MemMap.getCapacity(), "scudo:test",
+                 MAP_RESIZABLE | MAP_ALLOWNOMEM);
+    return MemMap;
+  }
+
+  void fillCacheWithSameSizeBlocks(std::vector<scudo::MemMapT> &MemMaps,
+                                   scudo::uptr NumEntries, scudo::uptr Size) {
+    for (scudo::uptr I = 0; I < NumEntries; I++) {
+      MemMaps.emplace_back(allocate(Size));
+      scudo::MemMapT &MemMap = MemMaps[I];
+      Cache->store(Options, MemMap.getBase(), MemMap.getCapacity(),
+                   MemMap.getBase(), MemMap);
+    }
+  }
+};
+
+TEST_F(MapAllocatorCacheTest, CacheOrder) {
+  std::vector<scudo::MemMapT> MemMaps;
+  Cache->setOption(scudo::Option::MaxCacheEntriesCount,
+                   CacheConfig::getEntriesArraySize());
+
+  fillCacheWithSameSizeBlocks(MemMaps, CacheConfig::getEntriesArraySize(),
+                              TestAllocSize);
+
+  // Retrieval order should be the inverse of insertion order
+  for (scudo::uptr I = CacheConfig::getEntriesArraySize(); I > 0; I--) {
+    scudo::uptr EntryHeaderPos;
+    scudo::CachedBlock Entry =
+        Cache->retrieve(TestAllocSize, PageSize, 0, EntryHeaderPos);
+    EXPECT_EQ(Entry.MemMap.getBase(), MemMaps[I - 1].getBase());
+  }
+
+  // Clean up MemMaps
+  for (scudo::MemMapT &MemMap : MemMaps)
----------------
cferris1000 wrote:

Probably easier to use auto here:

for (auto &MemMap : ...)

You can do this below too.

https://github.com/llvm/llvm-project/pull/102230