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

[Joshua Baehring via llvm-commits]

================
@@ -265,3 +265,99 @@ TEST_F(MapAllocatorWithReleaseTest, SecondaryThreadsRace) {
   Allocator->getStats(&Str);
   Str.output();
 }
+
+struct MapAllocatorCacheTest : public Test {
+  static constexpr scudo::u32 MarkerBytes = 0xDEADBEEF;
+
+  static void testUnmapCallback(scudo::MemMapT &MemMap) {
+    scudo::u32 *Ptr = reinterpret_cast<scudo::u32 *>(MemMap.getBase());
+    *Ptr = MarkerBytes;
+  }
+
+  using Config = scudo::DefaultConfig;
+  using SecondaryConfig = scudo::SecondaryConfig<Config>;
+  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();
+  static constexpr scudo::uptr DefaultAllocSize = scudo::uptr(1U) << 16;
+
+  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++)
----------------
JoshuaMBa wrote:

Right, this is a vestige of the previous version where the allocations had to be done separately so that `allocate()` wouldn't accidentally retrieve a cache entry. I'll update it to just be one loop.

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