Mark pages created during bootstrapping as never-evacuate.

src/heap/spaces.h

 // Copyright 2011 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.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
@@ skipping 355 matching lines @@
     ABOUT_TO_BE_FREED,
     POINTERS_TO_HERE_ARE_INTERESTING,
     POINTERS_FROM_HERE_ARE_INTERESTING,
     SCAN_ON_SCAVENGE,
     IN_FROM_SPACE,  // Mutually exclusive with IN_TO_SPACE.
     IN_TO_SPACE,    // All pages in new space has one of these two set.
     NEW_SPACE_BELOW_AGE_MARK,
     CONTAINS_ONLY_DATA,
     EVACUATION_CANDIDATE,
     RESCAN_ON_EVACUATION,
+    NEVER_EVACUATE,  // May contain immortal immutables.
 
     // WAS_SWEPT indicates that marking bits have been cleared by the sweeper,
     // otherwise marking bits are still intact.
     WAS_SWEPT,
 
     // Large objects can have a progress bar in their page header. These object
     // are scanned in increments and will be kept black while being scanned.
     // Even if the mutator writes to them they will be kept black and a white
     // to grey transition is performed in the value.
     HAS_PROGRESS_BAR,
@@ skipping 211 matching lines @@
     return this->address() + (index << kPointerSizeLog2);
   }
 
   void InsertAfter(MemoryChunk* other);
   void Unlink();
 
   inline Heap* heap() const { return heap_; }
 
   static const int kFlagsOffset = kPointerSize;
 
-  bool IsEvacuationCandidate() { return IsFlagSet(EVACUATION_CANDIDATE); }
+  bool NeverEvacuate() { return IsFlagSet(NEVER_EVACUATE); }
+
+  void MarkNeverEvacuate() { SetFlag(NEVER_EVACUATE); }
+
+  bool IsEvacuationCandidate() {
+    DCHECK(!(IsFlagSet(NEVER_EVACUATE) && IsFlagSet(EVACUATION_CANDIDATE)));
+    return IsFlagSet(EVACUATION_CANDIDATE);
+  }
 
   bool ShouldSkipEvacuationSlotRecording() {
     return (flags_ & kSkipEvacuationSlotsRecordingMask) != 0;
   }
 
   inline SkipList* skip_list() { return skip_list_; }
 
   inline void set_skip_list(SkipList* skip_list) { skip_list_ = skip_list; }
 
   inline SlotsBuffer* slots_buffer() { return slots_buffer_; }
 
   inline SlotsBuffer** slots_buffer_address() { return &slots_buffer_; }
 
   void MarkEvacuationCandidate() {
+    DCHECK(!IsFlagSet(NEVER_EVACUATE));
     DCHECK(slots_buffer_ == NULL);
     SetFlag(EVACUATION_CANDIDATE);
   }
 
   void ClearEvacuationCandidate() {
     DCHECK(slots_buffer_ == NULL);
     ClearFlag(EVACUATION_CANDIDATE);
   }
 
   Address area_start() { return area_start_; }
@@ skipping 2244 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_SPACES_H_