Refactor and cleanup VirtualMemory.

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index 428ba55b2eef763e129082475d776fd452d9efce..46bc2de5a81974a2ac93670eea452b3173860bb0 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -219,30 +219,6 @@ class OS {
   static void PrintError(const char* format, ...);
   static void VPrintError(const char* format, va_list args);
 
-  // Allocate/Free memory used by JS heap. Pages are readable/writable, but
-  // they are not guaranteed to be executable unless 'executable' is true.
-  // Returns the address of allocated memory, or NULL if failed.
-  static void* Allocate(const size_t requested,
-                        size_t* allocated,
-                        bool is_executable);
-  static void Free(void* address, const size_t size);
-
-  // This is the granularity at which the ProtectCode(...) call can set page
-  // permissions.
-  static intptr_t CommitPageSize();
-
-  // Mark code segments non-writable.
-  static void ProtectCode(void* address, const size_t size);
-
-  // Assign memory as a guard page so that access will cause an exception.
-  static void Guard(void* address, const size_t size);
-
-  // Generate a random address to be used for hinting mmap().
-  static void* GetRandomMmapAddr();
-
-  // Get the Alignment guaranteed by Allocate().
-  static size_t AllocateAlignment();
-
   // Sleep for a number of milliseconds.
   static void Sleep(const int milliseconds);
 
@@ -303,10 +279,6 @@ class OS {
   // positions indicated by the members of the CpuFeature enum from globals.h
   static uint64_t CpuFeaturesImpliedByPlatform();
 
-  // Maximum size of the virtual memory.  0 means there is no artificial
-  // limit.
-  static intptr_t MaxVirtualMemory();
-
   // Returns the double constant NAN
   static double nan_value();
 
@@ -386,99 +358,6 @@ class OS {
   DISALLOW_IMPLICIT_CONSTRUCTORS(OS);
 };
 
-// Represents and controls an area of reserved memory.
-// Control of the reserved memory can be assigned to another VirtualMemory
-// object by assignment or copy-contructing. This removes the reserved memory
-// from the original object.
-class VirtualMemory {
- public:
-  // Empty VirtualMemory object, controlling no reserved memory.
-  VirtualMemory();
-
-  // Reserves virtual memory with size.
-  explicit VirtualMemory(size_t size);
-
-  // Reserves virtual memory containing an area of the given size that
-  // is aligned per alignment. This may not be at the position returned
-  // by address().
-  VirtualMemory(size_t size, size_t alignment);
-
-  // Releases the reserved memory, if any, controlled by this VirtualMemory
-  // object.
-  ~VirtualMemory();
-
-  // Returns whether the memory has been reserved.
-  bool IsReserved();
-
-  // Initialize or resets an embedded VirtualMemory object.
-  void Reset();
-
-  // Returns the start address of the reserved memory.
-  // If the memory was reserved with an alignment, this address is not
-  // necessarily aligned. The user might need to round it up to a multiple of
-  // the alignment to get the start of the aligned block.
-  void* address() {
-    ASSERT(IsReserved());
-    return address_;
-  }
-
-  // Returns the size of the reserved memory. The returned value is only
-  // meaningful when IsReserved() returns true.
-  // If the memory was reserved with an alignment, this size may be larger
-  // than the requested size.
-  size_t size() { return size_; }
-
-  // Commits real memory. Returns whether the operation succeeded.
-  bool Commit(void* address, size_t size, bool is_executable);
-
-  // Uncommit real memory.  Returns whether the operation succeeded.
-  bool Uncommit(void* address, size_t size);
-
-  // Creates a single guard page at the given address.
-  bool Guard(void* address);
-
-  void Release() {
-    ASSERT(IsReserved());
-    // Notice: Order is important here. The VirtualMemory object might live
-    // inside the allocated region.
-    void* address = address_;
-    size_t size = size_;
-    Reset();
-    bool result = ReleaseRegion(address, size);
-    USE(result);
-    ASSERT(result);
-  }
-
-  // Assign control of the reserved region to a different VirtualMemory object.
-  // The old object is no longer functional (IsReserved() returns false).
-  void TakeControl(VirtualMemory* from) {
-    ASSERT(!IsReserved());
-    address_ = from->address_;
-    size_ = from->size_;
-    from->Reset();
-  }
-
-  static void* ReserveRegion(size_t size);
-
-  static bool CommitRegion(void* base, size_t size, bool is_executable);
-
-  static bool UncommitRegion(void* base, size_t size);
-
-  // Must be called with a base pointer that has been returned by ReserveRegion
-  // and the same size it was reserved with.
-  static bool ReleaseRegion(void* base, size_t size);
-
-  // Returns true if OS performs lazy commits, i.e. the memory allocation call
-  // defers actual physical memory allocation till the first memory access.
-  // Otherwise returns false.
-  static bool HasLazyCommits();
-
- private:
-  void* address_;  // Start address of the virtual memory.
-  size_t size_;  // Size of the virtual memory.
-};
-
-
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