- Add the ability to protect VirtualMemory.

runtime/vm/heap.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_HEAP_H_
 #define VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 27 matching lines @@
     kInvokeApiCallbacks
   };
 
   // Default allocation sizes in MB for the old gen and code heaps.
   static const intptr_t kHeapSizeInMB = 512;
   static const intptr_t kCodeHeapSizeInMB = 12;
 
   ~Heap();
 
   uword Allocate(intptr_t size, Space space) {
+    ASSERT(!read_only_);
     switch (space) {
       case kNew:
         // Do not attempt to allocate very large objects in new space.
         if (!PageSpace::IsPageAllocatableSize(size)) {
           return AllocateOld(size);
         }
         return AllocateNew(size);
       case kOld:
         return AllocateOld(size);
       case kCode:
         return AllocateCode(code_space_, size);
       default:
         UNREACHABLE();
     }
     return 0;
   }
 
   uword TryAllocate(intptr_t size, Space space) {
+    ASSERT(!read_only_);
     switch (space) {
       case kNew:
         return new_space_->TryAllocate(size);
       case kOld:
         return old_space_->TryAllocate(size);
       case kCode:
         return code_space_->TryAllocate(size);
       default:
         UNREACHABLE();
     }
@@ skipping 34 matching lines @@
   RawInstructions* FindObjectInStubCodeSpace(FindObjectVisitor* visitor);
 
   void CollectGarbage(Space space);
   void CollectGarbage(Space space, ApiCallbacks api_callbacks);
   void CollectAllGarbage();
 
   // Enables growth control on the page space heaps.  This should be
   // called before any user code is executed.
   void EnableGrowthControl();
 
+  // Protect access to the heap.
+  void WriteProtect(bool read_only);
+
   // Accessors for inlined allocation in generated code.
   uword TopAddress();
   uword EndAddress();
   static intptr_t new_space_offset() { return OFFSET_OF(Heap, new_space_); }
 
   // Initialize the heap and register it with the isolate.
   static void Init(Isolate* isolate);
 
   // Verify that all pointers in the heap point to the heap.
   bool Verify() const;
@@ skipping 14 matching lines @@
 
   uword AllocateNew(intptr_t size);
   uword AllocateOld(intptr_t size);
   uword AllocateCode(PageSpace* space, intptr_t size);
 
   // The different spaces used for allocation.
   Scavenger* new_space_;
   PageSpace* old_space_;
   PageSpace* code_space_;
 
+  // This heap is in read-only mode: No allocation is allowed.
+  bool read_only_;
+
   friend class GCTestHelper;
   DISALLOW_COPY_AND_ASSIGN(Heap);
 };
 
 
 #if defined(DEBUG)
 class NoGCScope : public StackResource {
  public:
   NoGCScope();
   ~NoGCScope();
  private:
   DISALLOW_COPY_AND_ASSIGN(NoGCScope);
 };
 #else  // defined(DEBUG)
 class NoGCScope : public ValueObject {
  public:
   NoGCScope() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(NoGCScope);
 };
 #endif  // defined(DEBUG)
 
 }  // namespace dart
 
 #endif  // VM_HEAP_H_