Implement unaligned allocate and allocate heap numbers in runtime double unaligned.

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 1947 matching lines @@
 
 
 STATIC_ASSERT((FixedDoubleArray::kHeaderSize & kDoubleAlignmentMask) ==
               0);  // NOLINT
 STATIC_ASSERT((ConstantPoolArray::kFirstEntryOffset & kDoubleAlignmentMask) ==
               0);  // NOLINT
 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::EnsureDoubleAligned(HeapObject* object, int size) {
-  if ((OffsetFrom(object->address()) & kDoubleAlignmentMask) != 0) {
+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;
   }
 }
 
 
+HeapObject* Heap::PrecedeWithFiller(HeapObject* object) {
+  CreateFillerObjectAt(object->address(), kPointerSize);
+  return HeapObject::FromAddress(object->address() + kPointerSize);
+}
+
+
 HeapObject* Heap::DoubleAlignForDeserialization(HeapObject* object, int size) {
-  return EnsureDoubleAligned(object, size);
+  return EnsureAligned(object, size, kDoubleAligned);
 }
 
 
 enum LoggingAndProfiling {
   LOGGING_AND_PROFILING_ENABLED,
   LOGGING_AND_PROFILING_DISABLED
 };
 
 
 enum MarksHandling { TRANSFER_MARKS, IGNORE_MARKS };
@@ skipping 131 matching lines @@
     }
   }
 
   template <int alignment>
   static inline bool SemiSpaceCopyObject(Map* map, HeapObject** slot,
                                          HeapObject* object, int object_size) {
     Heap* heap = map->GetHeap();
 
     DCHECK(heap->AllowedToBeMigrated(object, NEW_SPACE));
     AllocationResult allocation;
-#ifndef V8_HOST_ARCH_64_BIT
+#ifdef V8_HOST_ARCH_32_BIT
     if (alignment == kDoubleAlignment) {
-      allocation = heap->new_space()->AllocateRawDoubleAligned(object_size);
+      allocation =
+          heap->new_space()->AllocateRawAligned(object_size, kDoubleAligned);
     } else {
       allocation = heap->new_space()->AllocateRaw(object_size);
     }
 #else
     allocation = heap->new_space()->AllocateRaw(object_size);
 #endif
 
     HeapObject* target = NULL;  // Initialization to please compiler.
     if (allocation.To(&target)) {
       // Order is important here: Set the promotion limit before storing a
@@ skipping 13 matching lines @@
     return false;
   }
 
 
   template <ObjectContents object_contents, int alignment>
   static inline bool PromoteObject(Map* map, HeapObject** slot,
                                    HeapObject* object, int object_size) {
     Heap* heap = map->GetHeap();
 
     AllocationResult allocation;
-#ifndef V8_HOST_ARCH_64_BIT
+#ifdef V8_HOST_ARCH_32_BIT
     if (alignment == kDoubleAlignment) {
-      allocation = heap->old_space()->AllocateRawDoubleAligned(object_size);
+      allocation =
+          heap->old_space()->AllocateRawAligned(object_size, kDoubleAligned);
     } else {
       allocation = heap->old_space()->AllocateRaw(object_size);
     }
 #else
     allocation = heap->old_space()->AllocateRaw(object_size);
 #endif
 
     HeapObject* target = NULL;  // Initialization to please compiler.
     if (allocation.To(&target)) {
       MigrateObject(heap, object, target, object_size);
@@ skipping 650 matching lines @@
                                           PretenureFlag pretenure) {
   // 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);
+    AllocationResult allocation =
+        AllocateRaw(size, space, OLD_SPACE, kDoubleUnaligned);
     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 3656 matching lines @@
       }
       delete list;
     } else {
       prev = list;
     }
     list = next;
   }
 }
 }
 }  // namespace v8::internal