78   intptr_t pop() {
  79     assert(_sp < _top, "stack underflow");
  80     return *(_sp++);
  81   }
  82 
  83   void *alloc(size_t size) {
  84     int count = align_size_up(size, wordSize) >> LogBytesPerWord;
  85     assert(count <= available_words(), "stack overflow");
  86     return _sp -= count;
  87   }
  88 
  89   int shadow_pages_size() const {
  90     return _shadow_pages_size;
  91   }
  92 
  93  public:
  94   void overflow_check(int required_words, TRAPS);
  95   static void handle_overflow(TRAPS);
  96 
  97  public:



  98   static ByteSize base_offset() {
  99     return byte_offset_of(ZeroStack, _base);
 100   }
 101   static ByteSize top_offset() {
 102     return byte_offset_of(ZeroStack, _top);
 103   }
 104   static ByteSize sp_offset() {
 105     return byte_offset_of(ZeroStack, _sp);
 106   }
 107 };
 108 
 109 
 110 class EntryFrame;
 111 class InterpreterFrame;
 112 class SharkFrame;
 113 class FakeStubFrame;
 114 
 115 //
 116 // |  ...               |
 117 // +--------------------+  ------------------

  78   intptr_t pop() {
  79     assert(_sp < _top, "stack underflow");
  80     return *(_sp++);
  81   }
  82 
  83   void *alloc(size_t size) {
  84     int count = align_size_up(size, wordSize) >> LogBytesPerWord;
  85     assert(count <= available_words(), "stack overflow");
  86     return _sp -= count;
  87   }
  88 
  89   int shadow_pages_size() const {
  90     return _shadow_pages_size;
  91   }
  92 
  93  public:
  94   void overflow_check(int required_words, TRAPS);
  95   static void handle_overflow(TRAPS);
  96 
  97  public:
  98   void zap(int c) PRODUCT_RETURN;
  99 
 100  public:
 101   static ByteSize base_offset() {
 102     return byte_offset_of(ZeroStack, _base);
 103   }
 104   static ByteSize top_offset() {
 105     return byte_offset_of(ZeroStack, _top);
 106   }
 107   static ByteSize sp_offset() {
 108     return byte_offset_of(ZeroStack, _sp);
 109   }
 110 };
 111 
 112 
 113 class EntryFrame;
 114 class InterpreterFrame;
 115 class SharkFrame;
 116 class FakeStubFrame;
 117 
 118 //
 119 // |  ...               |
 120 // +--------------------+  ------------------