Index: lib/hwasan/hwasan_allocator.h
===================================================================
--- lib/hwasan/hwasan_allocator.h
+++ lib/hwasan/hwasan_allocator.h
@@ -45,28 +45,22 @@
 };
 
 static const uptr kMaxAllowedMallocSize = 2UL << 30;  // 2G
-static const uptr kRegionSizeLog = 20;
-static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
-typedef TwoLevelByteMap<(kNumRegions >> 12), 1 << 12> ByteMap;
-
-struct AP32 {
-  static const uptr kSpaceBeg = 0;
-  static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
+
+struct AP64 {
+  static const uptr kSpaceBeg = ~0ULL;
+  static const uptr kSpaceSize = 0x2000000000ULL;
   static const uptr kMetadataSize = sizeof(Metadata);
-  typedef __sanitizer::CompactSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = __hwasan::kRegionSizeLog;
+  typedef __sanitizer::VeryDenseSizeClassMap SizeClassMap;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __hwasan::ByteMap;
   typedef HwasanMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
-typedef SizeClassAllocator32<AP32> PrimaryAllocator;
+typedef SizeClassAllocator64<AP64> PrimaryAllocator;
 typedef SizeClassAllocatorLocalCache<PrimaryAllocator> AllocatorCache;
 typedef LargeMmapAllocator<HwasanMapUnmapCallback> SecondaryAllocator;
 typedef CombinedAllocator<PrimaryAllocator, AllocatorCache,
                           SecondaryAllocator> Allocator;
 
-
 void AllocatorSwallowThreadLocalCache(AllocatorCache *cache);
 
 class HwasanChunkView {
Index: lib/sanitizer_common/sanitizer_allocator_combined.h
===================================================================
--- lib/sanitizer_common/sanitizer_allocator_combined.h
+++ lib/sanitizer_common/sanitizer_allocator_combined.h
@@ -34,15 +34,15 @@
                 "SecondaryAllocator is using wrong AddressSpaceView");
 
   void InitLinkerInitialized(s32 release_to_os_interval_ms) {
+    stats_.InitLinkerInitialized();
     primary_.Init(release_to_os_interval_ms);
     secondary_.InitLinkerInitialized();
-    stats_.InitLinkerInitialized();
   }
 
   void Init(s32 release_to_os_interval_ms) {
+    stats_.Init();
     primary_.Init(release_to_os_interval_ms);
     secondary_.Init();
-    stats_.Init();
   }
 
   void *Allocate(AllocatorCache *cache, uptr size, uptr alignment) {
Index: lib/sanitizer_common/sanitizer_allocator_size_class_map.h
===================================================================
--- lib/sanitizer_common/sanitizer_allocator_size_class_map.h
+++ lib/sanitizer_common/sanitizer_allocator_size_class_map.h
@@ -237,3 +237,6 @@
 // allowing for denser per-class arrays, smaller memory footprint and usually
 // better performances in threaded environments.
 typedef SizeClassMap<3, 4, 8, 17, 8, 10> DenseSizeClassMap;
+// Similar to VeryCompact map above, this one has a small number of different
+// size classes, and also reduced thread-local caches.
+typedef SizeClassMap<2, 5, 9, 16, 8, 10> VeryDenseSizeClassMap;
Index: test/hwasan/TestCases/heap-buffer-overflow.c
===================================================================
--- test/hwasan/TestCases/heap-buffer-overflow.c
+++ test/hwasan/TestCases/heap-buffer-overflow.c
@@ -43,7 +43,6 @@
 // CHECK80-RIGHT: allocated heap chunk; size: 32 offset:
 // CHECK80-RIGHT: is located 50 bytes to the right of 30-byte region
 //
-// CHECKm30: allocated heap chunk; size: 32 offset: 2
 // CHECKm30: is located 30 bytes to the left of 30-byte region
 //
 // CHECKMm30: is a large allocated heap chunk; size: 1003520 offset: -30
Index: test/hwasan/TestCases/use-after-free.c
===================================================================
--- test/hwasan/TestCases/use-after-free.c
+++ test/hwasan/TestCases/use-after-free.c
@@ -23,7 +23,7 @@
   // CHECK: [[TYPE]] of size 1 at {{.*}} tags: [[PTR_TAG:[0-9a-f][0-9a-f]]]/[[MEM_TAG:[0-9a-f][0-9a-f]]] (ptr/mem)
   // CHECK: #0 {{.*}} in main {{.*}}use-after-free.c:[[@LINE-2]]
   // Offset is 5 or 11 depending on left/right alignment.
-  // CHECK: is a small unallocated heap chunk; size: 16 offset: {{5|11}}
+  // CHECK: is a small unallocated heap chunk; size: 32 offset: {{5|11}}
   // CHECK: is located 5 bytes inside of 10-byte region
   //
   // CHECK: freed by thread {{.*}} here: