src/share/vm/runtime/thread.hpp

rev 4810 : 8017313: PPC64 (part 6): stack handling improvements
Summary: Precompute limit for stack overflow check.
Reviewed-by: kvn, coleenp

@@ -893,10 +893,14 @@
 
  private:
 
   StackGuardState        _stack_guard_state;
 
+  // Precompute the limit of the stack as used in stack overflow checks.
+  // We load it from here to simplify the stack overflow check in assembly.
+  address          _stack_overflow_limit;
+
   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
   // code)
   volatile oop     _exception_oop;               // Exception thrown in compiled code
   volatile address _exception_pc;                // PC where exception happened

@@ -1299,10 +1303,18 @@
   bool reguard_stack(address cur_sp);
   // Similar to above but see if current stackpoint is out of the guard area
   // and reguard if possible.
   bool reguard_stack(void);
 
+  address stack_overflow_limit() { return _stack_overflow_limit; }
+  void set_stack_overflow_limit() {
+    _stack_overflow_limit = _stack_base - _stack_size +
+              ((StackShadowPages +
+                StackYellowPages +
+                StackRedPages) * os::vm_page_size());
+  }
+
   // Misc. accessors/mutators
   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
 

@@ -1333,10 +1345,11 @@
   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
+  static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
 
   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }