Make top and limit field in AllocationInfo private, assert on non-aligned setting of these fields, …

src/spaces.cc

Index: src/spaces.cc
diff --git a/src/spaces.cc b/src/spaces.cc
index ee6a890424be06e7da351c44c5f2757cbb214a9a..fe5eeb5e4311fe434b952261239fed62999e43b7 100644
--- a/src/spaces.cc
+++ b/src/spaces.cc
@@ -960,8 +960,8 @@ PagedSpace::PagedSpace(Heap* heap,
       * AreaSize();
   accounting_stats_.Clear();
 
-  allocation_info_.top = NULL;
-  allocation_info_.limit = NULL;
+  allocation_info_.set_top(NULL);
+  allocation_info_.set_limit(NULL);
 
   anchor_.InitializeAsAnchor(this);
 }
@@ -990,7 +990,7 @@ void PagedSpace::TearDown() {
 
 size_t PagedSpace::CommittedPhysicalMemory() {
   if (!VirtualMemory::HasLazyCommits()) return CommittedMemory();
-  MemoryChunk::UpdateHighWaterMark(allocation_info_.top);
+  MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
   size_t size = 0;
   PageIterator it(this);
   while (it.has_next()) {
@@ -1142,8 +1142,9 @@ void PagedSpace::ReleasePage(Page* page, bool unlink) {
     DecreaseUnsweptFreeBytes(page);
   }
 
-  if (Page::FromAllocationTop(allocation_info_.top) == page) {
-    allocation_info_.top = allocation_info_.limit = NULL;
+  if (Page::FromAllocationTop(allocation_info_.top()) == page) {
+    allocation_info_.set_top(NULL);
+    allocation_info_.set_limit(NULL);
   }
 
   if (unlink) {
@@ -1170,12 +1171,12 @@ void PagedSpace::Verify(ObjectVisitor* visitor) {
   if (was_swept_conservatively_) return;
 
   bool allocation_pointer_found_in_space =
-      (allocation_info_.top == allocation_info_.limit);
+      (allocation_info_.top() == allocation_info_.limit());
   PageIterator page_iterator(this);
   while (page_iterator.has_next()) {
     Page* page = page_iterator.next();
     CHECK(page->owner() == this);
-    if (page == Page::FromAllocationTop(allocation_info_.top)) {
+    if (page == Page::FromAllocationTop(allocation_info_.top())) {
       allocation_pointer_found_in_space = true;
     }
     CHECK(page->WasSweptPrecisely());
@@ -1286,8 +1287,8 @@ void NewSpace::TearDown() {
   }
 
   start_ = NULL;
-  allocation_info_.top = NULL;
-  allocation_info_.limit = NULL;
+  allocation_info_.set_top(NULL);
+  allocation_info_.set_limit(NULL);
 
   to_space_.TearDown();
   from_space_.TearDown();
@@ -1344,22 +1345,22 @@ void NewSpace::Shrink() {
       }
     }
   }
-  allocation_info_.limit = to_space_.page_high();
+  allocation_info_.set_limit(to_space_.page_high());
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
 
 
 void NewSpace::UpdateAllocationInfo() {
-  MemoryChunk::UpdateHighWaterMark(allocation_info_.top);
-  allocation_info_.top = to_space_.page_low();
-  allocation_info_.limit = to_space_.page_high();
+  MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+  allocation_info_.set_top(to_space_.page_low());
+  allocation_info_.set_limit(to_space_.page_high());
 
   // Lower limit during incremental marking.
   if (heap()->incremental_marking()->IsMarking() &&
       inline_allocation_limit_step() != 0) {
     Address new_limit =
-        allocation_info_.top + inline_allocation_limit_step();
-    allocation_info_.limit = Min(new_limit, allocation_info_.limit);
+        allocation_info_.top() + inline_allocation_limit_step();
+    allocation_info_.set_limit(Min(new_limit, allocation_info_.limit()));
   }
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
@@ -1378,7 +1379,7 @@ void NewSpace::ResetAllocationInfo() {
 
 
 bool NewSpace::AddFreshPage() {
-  Address top = allocation_info_.top;
+  Address top = allocation_info_.top();
   if (NewSpacePage::IsAtStart(top)) {
     // The current page is already empty. Don't try to make another.
 
@@ -1410,15 +1411,16 @@ bool NewSpace::AddFreshPage() {
 
 
 MaybeObject* NewSpace::SlowAllocateRaw(int size_in_bytes) {
-  Address old_top = allocation_info_.top;
+  Address old_top = allocation_info_.top();
   Address new_top = old_top + size_in_bytes;
   Address high = to_space_.page_high();
-  if (allocation_info_.limit < high) {
+  if (allocation_info_.limit() < high) {
     // Incremental marking has lowered the limit to get a
     // chance to do a step.
-    allocation_info_.limit = Min(
-        allocation_info_.limit + inline_allocation_limit_step_,
+    Address new_limit = Min(
+        allocation_info_.limit() + inline_allocation_limit_step_,
         high);
+    allocation_info_.set_limit(new_limit);
     int bytes_allocated = static_cast<int>(new_top - top_on_previous_step_);
     heap()->incremental_marking()->Step(
         bytes_allocated, IncrementalMarking::GC_VIA_STACK_GUARD);
@@ -1973,7 +1975,7 @@ void NewSpace::RecordPromotion(HeapObject* obj) {
 
 size_t NewSpace::CommittedPhysicalMemory() {
   if (!VirtualMemory::HasLazyCommits()) return CommittedMemory();
-  MemoryChunk::UpdateHighWaterMark(allocation_info_.top);
+  MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
   size_t size = to_space_.CommittedPhysicalMemory();
   if (from_space_.is_committed()) {
     size += from_space_.CommittedPhysicalMemory();
@@ -2499,9 +2501,9 @@ bool NewSpace::ReserveSpace(int bytes) {
   Object* object = NULL;
   if (!maybe->ToObject(&object)) return false;
   HeapObject* allocation = HeapObject::cast(object);
-  Address top = allocation_info_.top;
+  Address top = allocation_info_.top();
   if ((top - bytes) == allocation->address()) {
-    allocation_info_.top = allocation->address();
+    allocation_info_.set_top(allocation->address());
     return true;
   }
   // There may be a borderline case here where the allocation succeeded, but
@@ -2547,9 +2549,9 @@ void PagedSpace::PrepareForMarkCompact() {
 bool PagedSpace::ReserveSpace(int size_in_bytes) {
   ASSERT(size_in_bytes <= AreaSize());
   ASSERT(size_in_bytes == RoundSizeDownToObjectAlignment(size_in_bytes));
-  Address current_top = allocation_info_.top;
+  Address current_top = allocation_info_.top();
   Address new_top = current_top + size_in_bytes;
-  if (new_top <= allocation_info_.limit) return true;
+  if (new_top <= allocation_info_.limit()) return true;
 
   HeapObject* new_area = free_list_.Allocate(size_in_bytes);
   if (new_area == NULL) new_area = SlowAllocateRaw(size_in_bytes);
@@ -2624,16 +2626,17 @@ bool PagedSpace::AdvanceSweeper(intptr_t bytes_to_sweep) {
 
 
 void PagedSpace::EvictEvacuationCandidatesFromFreeLists() {
-  if (allocation_info_.top >= allocation_info_.limit) return;
+  if (allocation_info_.top() >= allocation_info_.limit()) return;
 
-  if (Page::FromAllocationTop(allocation_info_.top)->IsEvacuationCandidate()) {
+  if (Page::FromAllocationTop(allocation_info_.top())->
+      IsEvacuationCandidate()) {
     // Create filler object to keep page iterable if it was iterable.
     int remaining =
-        static_cast<int>(allocation_info_.limit - allocation_info_.top);
-    heap()->CreateFillerObjectAt(allocation_info_.top, remaining);
+        static_cast<int>(allocation_info_.limit() - allocation_info_.top());
+    heap()->CreateFillerObjectAt(allocation_info_.top(), remaining);
 
-    allocation_info_.top = NULL;
-    allocation_info_.limit = NULL;
+    allocation_info_.set_top(NULL);
+    allocation_info_.set_limit(NULL);
   }
 }