Clean up aligned allocation code in preparation for SIMD alignments.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 1954 matching lines @@
 STATIC_ASSERT((ConstantPoolArray::kExtendedFirstOffset &
                kDoubleAlignmentMask) == 0);  // NOLINT
 STATIC_ASSERT((FixedTypedArrayBase::kDataOffset & kDoubleAlignmentMask) ==
               0);  // NOLINT
 #ifdef V8_HOST_ARCH_32_BIT
 STATIC_ASSERT((HeapNumber::kValueOffset & kDoubleAlignmentMask) !=
               0);  // NOLINT
 #endif
 
 
-HeapObject* Heap::EnsureAligned(HeapObject* object, int size,
-                                AllocationAlignment alignment) {
-  if (alignment == kDoubleAligned &&
-      (OffsetFrom(object->address()) & kDoubleAlignmentMask) != 0) {
-    CreateFillerObjectAt(object->address(), kPointerSize);
-    return HeapObject::FromAddress(object->address() + kPointerSize);
-  } else if (alignment == kDoubleUnaligned &&
-             (OffsetFrom(object->address()) & kDoubleAlignmentMask) == 0) {
-    CreateFillerObjectAt(object->address(), kPointerSize);
-    return HeapObject::FromAddress(object->address() + kPointerSize);
-  } else {
-    CreateFillerObjectAt(object->address() + size - kPointerSize, kPointerSize);
-    return object;
-  }
+int Heap::GetAlignmentSize(Address address, AllocationAlignment alignment) {
+  intptr_t offset = OffsetFrom(address);
+  if (alignment == kDoubleAligned && (offset & kDoubleAlignmentMask) != 0)
+    return kPointerSize;
+  if (alignment == kDoubleValueAligned && (offset & kDoubleAlignmentMask) == 0)
+    return kPointerSize;
+  return 0;
 }
 
 
-HeapObject* Heap::PrecedeWithFiller(HeapObject* object) {
-  CreateFillerObjectAt(object->address(), kPointerSize);
-  return HeapObject::FromAddress(object->address() + kPointerSize);
+HeapObject* Heap::PrecedeWithFiller(HeapObject* object, int fill_size) {
+  CreateFillerObjectAt(object->address(), fill_size);
+  return HeapObject::FromAddress(object->address() + fill_size);
 }
 
 
 HeapObject* Heap::DoubleAlignForDeserialization(HeapObject* object, int size) {
-  return EnsureAligned(object, size, kDoubleAligned);
+  Address address = object->address();
+  int fill_size = GetAlignmentSize(address, kDoubleAligned);
+  // If object is not aligned, add fill to align it.
+  if (fill_size) return PrecedeWithFiller(object, kPointerSize);
+
+  // object is aligned. Add fill in the extra space at the end.
+  // TODO(bbudge) Calculate alignment fill earlier to avoid this.
+  CreateFillerObjectAt(address + size - kPointerSize, kPointerSize);
+  return object;
 }
 
 
 enum LoggingAndProfiling {
   LOGGING_AND_PROFILING_ENABLED,
   LOGGING_AND_PROFILING_DISABLED
 };
 
 
 enum MarksHandling { TRANSFER_MARKS, IGNORE_MARKS };
@@ skipping 830 matching lines @@
   // Statically ensure that it is safe to allocate heap numbers in paged
   // spaces.
   int size = HeapNumber::kSize;
   STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxRegularHeapObjectSize);
 
   AllocationSpace space = SelectSpace(size, pretenure);
 
   HeapObject* result;
   {
     AllocationResult allocation =
-        AllocateRaw(size, space, OLD_SPACE, kDoubleUnaligned);
+        AllocateRaw(size, space, OLD_SPACE, kDoubleValueAligned);
     if (!allocation.To(&result)) return allocation;
   }
 
   Map* map = mode == MUTABLE ? mutable_heap_number_map() : heap_number_map();
   HeapObject::cast(result)->set_map_no_write_barrier(map);
   HeapNumber::cast(result)->set_value(value);
   return result;
 }
 
 
@@ skipping 3684 matching lines @@
     *object_type = "CODE_TYPE";                                                \
     *object_sub_type = "CODE_AGE/" #name;                                      \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 }
 }  // namespace v8::internal