[sanitizer] allocator: split the local cache class into two, one for 32-bit allocator and one for 64-bit one. NFC. The two imlementations will diverge in the following changes.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@279495 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 150 insertions, 1 deletions

diff --git a/lib/sanitizer_common/sanitizer_allocator_local_cache.h b/lib/sanitizer_common/sanitizer_allocator_local_cache.h
index 0ad22bae3..a61245fdd 100644
--- a/lib/sanitizer_common/sanitizer_allocator_local_cache.h
+++ b/lib/sanitizer_common/sanitizer_allocator_local_cache.h
@@ -18,7 +18,155 @@
 // or SizeClassAllocator32. Since the typical use of this class is to have one
 // object per thread in TLS, is has to be POD.
 template<class SizeClassAllocator>
-struct SizeClassAllocatorLocalCache {
+struct SizeClassAllocatorLocalCache
+    : SizeClassAllocator::AllocatorCache {
+};
+
+// Cache used by SizeClassAllocator64.
+template <class SizeClassAllocator>
+struct SizeClassAllocator64LocalCache {
+  typedef SizeClassAllocator Allocator;
+  typedef typename Allocator::TransferBatch TransferBatch;
+  static const uptr kNumClasses = SizeClassAllocator::kNumClasses;
+
+  void Init(AllocatorGlobalStats *s) {
+    stats_.Init();
+    if (s)
+      s->Register(&stats_);
+  }
+
+  void Destroy(SizeClassAllocator *allocator, AllocatorGlobalStats *s) {
+    Drain(allocator);
+    if (s)
+      s->Unregister(&stats_);
+  }
+
+  void *Allocate(SizeClassAllocator *allocator, uptr class_id) {
+    CHECK_NE(class_id, 0UL);
+    CHECK_LT(class_id, kNumClasses);
+    stats_.Add(AllocatorStatAllocated, Allocator::ClassIdToSize(class_id));
+    PerClass *c = &per_class_[class_id];
+    if (UNLIKELY(c->count == 0))
+      Refill(allocator, class_id);
+    void *res = c->batch[--c->count];
+    PREFETCH(c->batch[c->count - 1]);
+    return res;
+  }
+
+  void Deallocate(SizeClassAllocator *allocator, uptr class_id, void *p) {
+    CHECK_NE(class_id, 0UL);
+    CHECK_LT(class_id, kNumClasses);
+    // If the first allocator call on a new thread is a deallocation, then
+    // max_count will be zero, leading to check failure.
+    InitCache();
+    stats_.Sub(AllocatorStatAllocated, Allocator::ClassIdToSize(class_id));
+    PerClass *c = &per_class_[class_id];
+    CHECK_NE(c->max_count, 0UL);
+    if (UNLIKELY(c->count == c->max_count))
+      Drain(allocator, class_id);
+    c->batch[c->count++] = p;
+  }
+
+  void Drain(SizeClassAllocator *allocator) {
+    for (uptr class_id = 0; class_id < kNumClasses; class_id++) {
+      PerClass *c = &per_class_[class_id];
+      while (c->count > 0)
+        Drain(allocator, class_id);
+    }
+  }
+
+  // private:
+  typedef typename SizeClassAllocator::SizeClassMapT SizeClassMap;
+  struct PerClass {
+    uptr count;
+    uptr max_count;
+    void *batch[2 * TransferBatch::kMaxNumCached];
+  };
+  PerClass per_class_[kNumClasses];
+  AllocatorStats stats_;
+
+  void InitCache() {
+    if (per_class_[1].max_count)
+      return;
+    for (uptr i = 0; i < kNumClasses; i++) {
+      PerClass *c = &per_class_[i];
+      c->max_count = 2 * TransferBatch::MaxCached(i);
+    }
+  }
+
+  // TransferBatch class is declared in SizeClassAllocator.
+  // We transfer chunks between central and thread-local free lists in batches.
+  // For small size classes we allocate batches separately.
+  // For large size classes we may use one of the chunks to store the batch.
+  // sizeof(TransferBatch) must be a power of 2 for more efficient allocation.
+
+  // If kUseSeparateSizeClassForBatch is true,
+  // all TransferBatch objects are allocated from kBatchClassID
+  // size class (except for those that are needed for kBatchClassID itself).
+  // The goal is to have TransferBatches in a totally different region of RAM
+  // to improve security and allow more efficient RAM reclamation.
+  // This is experimental and may currently increase memory usage by up to 3%
+  // in extreme cases.
+  static const bool kUseSeparateSizeClassForBatch = false;
+
+  static uptr SizeClassForTransferBatch(uptr class_id) {
+    if (kUseSeparateSizeClassForBatch)
+      return class_id == SizeClassMap::kBatchClassID
+                 ? 0
+                 : SizeClassMap::kBatchClassID;
+    if (Allocator::ClassIdToSize(class_id) <
+        TransferBatch::AllocationSizeRequiredForNElements(
+            TransferBatch::MaxCached(class_id)))
+      return SizeClassMap::ClassID(sizeof(TransferBatch));
+    return 0;
+  }
+
+  // Returns a TransferBatch suitable for class_id.
+  // For small size classes allocates the batch from the allocator.
+  // For large size classes simply returns b.
+  TransferBatch *CreateBatch(uptr class_id, SizeClassAllocator *allocator,
+                             TransferBatch *b) {
+    if (uptr batch_class_id = SizeClassForTransferBatch(class_id))
+      return (TransferBatch*)Allocate(allocator, batch_class_id);
+    return b;
+  }
+
+  // Destroys TransferBatch b.
+  // For small size classes deallocates b to the allocator.
+  // Does notthing for large size classes.
+  void DestroyBatch(uptr class_id, SizeClassAllocator *allocator,
+                    TransferBatch *b) {
+    if (uptr batch_class_id = SizeClassForTransferBatch(class_id))
+      Deallocate(allocator, batch_class_id, b);
+  }
+
+  NOINLINE void Refill(SizeClassAllocator *allocator, uptr class_id) {
+    InitCache();
+    PerClass *c = &per_class_[class_id];
+    TransferBatch *b = allocator->AllocateBatch(&stats_, this, class_id);
+    CHECK_GT(b->Count(), 0);
+    b->CopyToArray(c->batch);
+    c->count = b->Count();
+    DestroyBatch(class_id, allocator, b);
+  }
+
+  NOINLINE void Drain(SizeClassAllocator *allocator, uptr class_id) {
+    InitCache();
+    PerClass *c = &per_class_[class_id];
+    uptr cnt = Min(c->max_count / 2, c->count);
+    uptr first_idx_to_drain = c->count - cnt;
+    TransferBatch *b = CreateBatch(
+        class_id, allocator, (TransferBatch *)c->batch[first_idx_to_drain]);
+    b->SetFromArray(allocator->GetRegionBeginBySizeClass(class_id),
+                    &c->batch[first_idx_to_drain], cnt);
+    c->count -= cnt;
+    allocator->DeallocateBatch(&stats_, class_id, b);
+  }
+};
+
+// Cache used by SizeClassAllocator32.
+template <class SizeClassAllocator>
+struct SizeClassAllocator32LocalCache {
   typedef SizeClassAllocator Allocator;
   typedef typename Allocator::TransferBatch TransferBatch;
   static const uptr kNumClasses = SizeClassAllocator::kNumClasses;
@@ -157,3 +305,4 @@ struct SizeClassAllocatorLocalCache {
     allocator->DeallocateBatch(&stats_, class_id, b);
   }
 };
+