429168: fix for PdfJs regression

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 1590 matching lines @@
   FreeListCategory huge_list_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FreeList);
 };
 
 
 class AllocationResult {
  public:
   // Implicit constructor from Object*.
   AllocationResult(Object* object)  // NOLINT
-      : object_(object),
-        retry_space_(INVALID_SPACE) {}
+      : object_(object) {
+    // AllocationResults can't return Smis, which are used to represent
+    // failure and the space to retry in.
+    CHECK(!object->IsSmi());
+  }
 
-  AllocationResult() : object_(NULL), retry_space_(INVALID_SPACE) {}
+  AllocationResult() : object_(Smi::FromInt(NEW_SPACE)) {}
 
   static inline AllocationResult Retry(AllocationSpace space = NEW_SPACE) {
     return AllocationResult(space);
   }
 
-  inline bool IsRetry() { return retry_space_ != INVALID_SPACE; }
+  inline bool IsRetry() { return object_->IsSmi(); }
 
   template <typename T>
   bool To(T** obj) {
     if (IsRetry()) return false;
     *obj = T::cast(object_);
     return true;
   }
 
   Object* ToObjectChecked() {
     CHECK(!IsRetry());
     return object_;
   }
 
   AllocationSpace RetrySpace() {
     DCHECK(IsRetry());
-    return retry_space_;
+    return static_cast<AllocationSpace>(Smi::cast(object_)->value());
   }
 
  private:
   explicit AllocationResult(AllocationSpace space)
-      : object_(NULL), retry_space_(space) {}
+      : object_(Smi::FromInt(static_cast<int>(space))) {}
 
   Object* object_;
-  AllocationSpace retry_space_;
 };
 
 
+STATIC_ASSERT(sizeof(AllocationResult) == kPointerSize);
+
+
 class PagedSpace : public Space {
  public:
   // Creates a space with a maximum capacity, and an id.
   PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
              Executability executable);
 
   virtual ~PagedSpace() {}
 
   // Set up the space using the given address range of virtual memory (from
   // the memory allocator's initial chunk) if possible.  If the block of
@@ skipping 1236 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_