Some optimizations for the array alloc path.

- Force Array::Alloc() to be inlined.
- Simplify the array size overflow check.
- Turn fill_usable into a template parameter.
- Remove a branch in Array::DataOffset() and avoid
  Primitive::ComponentSize(), which has a switch, in the array alloc
  path.
- Strength reductions in the array size computation by using component
  size shifts instead of component sizes. Store component size shift
  in the upper 16 bits of primitive_type field.
- Speedup: ~4% (3435->3284) in MemAllocTest on N4.

Bug: 9986565

Change-Id: I4b142ffac4ab8b5b915836f1660a949d6442344c

1 files changed, 3 insertions, 3 deletions

diff --git a/runtime/entrypoints/entrypoint_utils-inl.h b/runtime/entrypoints/entrypoint_utils-inl.h
index 4ef7d741f7..9fb9a3ba56 100644
--- a/runtime/entrypoints/entrypoint_utils-inl.h
+++ b/runtime/entrypoints/entrypoint_utils-inl.h
@@ -230,11 +230,11 @@ static inline mirror::Array* AllocArrayFromCode(uint32_t type_idx,
     }
     gc::Heap* heap = Runtime::Current()->GetHeap();
     return mirror::Array::Alloc<kInstrumented>(self, klass, component_count,
-                                               klass->GetComponentSize(),
+                                               klass->GetComponentSizeShift(),
                                                heap->GetCurrentAllocator());
   }
   return mirror::Array::Alloc<kInstrumented>(self, klass, component_count,
-                                             klass->GetComponentSize(), allocator_type);
+                                             klass->GetComponentSizeShift(), allocator_type);
 }
 
 template <bool kAccessCheck, bool kInstrumented>
@@ -259,7 +259,7 @@ static inline mirror::Array* AllocArrayFromCodeResolved(mirror::Class* klass,
   // No need to retry a slow-path allocation as the above code won't cause a GC or thread
   // suspension.
   return mirror::Array::Alloc<kInstrumented>(self, klass, component_count,
-                                             klass->GetComponentSize(), allocator_type);
+                                             klass->GetComponentSizeShift(), allocator_type);
 }
 
 template<FindFieldType type, bool access_check>