src/share/vm/interpreter/invocationCounter.hpp

rev 7045 : 7115356: assert(!m->was_never_executed()) failed
Summary: Race when asserting on invocation counters
Reviewed-by:

*** 28,100 ****
  #include "memory/allocation.hpp"
  #include "runtime/handles.hpp"
  #include "utilities/exceptions.hpp"
  
  // InvocationCounters are used to trigger actions when a limit (threshold) is reached.
- // For different states, different limits and actions can be defined in the initialization
- // routine of InvocationCounters.
  //
! // Implementation notes: For space reasons, state & counter are both encoded in one word,
! // The state is encoded using some of the least significant bits, the counter is using the
  // more significant bits. The counter is incremented before a method is activated and an
! // action is triggered when when count() > limit().
  
  class InvocationCounter VALUE_OBJ_CLASS_SPEC {
    friend class VMStructs;
    friend class ciReplay;
!  private:                             // bit no: |31  3|  2  | 1 0 |
!   unsigned int _counter;              // format: [count|carry|state]
  
    enum PrivateConstants {
-     number_of_state_bits = 2,
      number_of_carry_bits = 1,
!     number_of_noncount_bits = number_of_state_bits + number_of_carry_bits,
      number_of_count_bits = BitsPerInt - number_of_noncount_bits,
!     state_limit          = nth_bit(number_of_state_bits),
!     count_grain          = nth_bit(number_of_state_bits + number_of_carry_bits),
!     carry_mask           = right_n_bits(number_of_carry_bits) << number_of_state_bits,
!     state_mask           = right_n_bits(number_of_state_bits),
!     status_mask          = right_n_bits(number_of_state_bits + number_of_carry_bits),
!     count_mask           = ((int)(-1) ^ status_mask)
    };
  
   public:
    static int InterpreterInvocationLimit;        // CompileThreshold scaled for interpreter use
    static int InterpreterBackwardBranchLimit;    // A separate threshold for on stack replacement
    static int InterpreterProfileLimit;           // Profiling threshold scaled for interpreter use
  
-   typedef address (*Action)(methodHandle method, TRAPS);
- 
    enum PublicConstants {
      count_increment      = count_grain,          // use this value to increment the 32bit _counter word
      count_mask_value     = count_mask,           // use this value to mask the backedge counter
      count_shift          = number_of_noncount_bits,
      count_limit          = nth_bit(number_of_count_bits - 1)
    };
  
-   enum State {
-     wait_for_nothing,                            // do nothing when count() > limit()
-     wait_for_compile,                            // introduce nmethod when count() > limit()
-     number_of_states                             // must be <= state_limit
-   };
- 
    // Manipulation
!   void reset();                                  // sets state to wait state
!   void init();                                   // sets state into original state
!   void set_state(State state);                   // sets state and initializes counter correspondingly
!   inline void set(State state, int count);       // sets state and counter
    inline void decay();                           // decay counter (divide by two)
!   void set_carry();                              // set the sticky carry bit
!   void set_carry_flag()                          {  _counter |= carry_mask; }
  
!   int raw_counter()                              { return _counter; }
  
    // Accessors
-   State  state() const                           { return (State)(_counter & state_mask); }
    bool   carry() const                           { return (_counter & carry_mask) != 0; }
-   int    limit() const                           { return CompileThreshold; }
-   Action action() const                          { return _action[state()]; }
    int    count() const                           { return _counter >> number_of_noncount_bits; }
  
    int   get_InvocationLimit() const              { return InterpreterInvocationLimit >> number_of_noncount_bits; }
    int   get_BackwardBranchLimit() const          { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; }
    int   get_ProfileLimit() const                 { return InterpreterProfileLimit >> number_of_noncount_bits; }
--- 28,93 ----
  #include "memory/allocation.hpp"
  #include "runtime/handles.hpp"
  #include "utilities/exceptions.hpp"
  
  // InvocationCounters are used to trigger actions when a limit (threshold) is reached.
  //
! // Implementation notes: For space reasons, counter & carry are both encoded in one word,
! // The carry is encoded using the least significant bits the counter is using the
  // more significant bits. The counter is incremented before a method is activated and an
! // action is triggered when when count() > the limit for that counter type.
  
  class InvocationCounter VALUE_OBJ_CLASS_SPEC {
    friend class VMStructs;
    friend class ciReplay;
!  private:                             // bit no: |31  1|  0  |
!   unsigned int _counter;              // format: [count|carry|
  
    enum PrivateConstants {
      number_of_carry_bits = 1,
!     number_of_noncount_bits = number_of_carry_bits,
      number_of_count_bits = BitsPerInt - number_of_noncount_bits,
!     count_grain          = nth_bit(number_of_carry_bits),
!     carry_mask           = right_n_bits(number_of_carry_bits),
!     count_mask           = ((int)(-1) ^ carry_mask)
    };
  
   public:
    static int InterpreterInvocationLimit;        // CompileThreshold scaled for interpreter use
    static int InterpreterBackwardBranchLimit;    // A separate threshold for on stack replacement
    static int InterpreterProfileLimit;           // Profiling threshold scaled for interpreter use
  
    enum PublicConstants {
      count_increment      = count_grain,          // use this value to increment the 32bit _counter word
      count_mask_value     = count_mask,           // use this value to mask the backedge counter
      count_shift          = number_of_noncount_bits,
      count_limit          = nth_bit(number_of_count_bits - 1)
    };
  
    // Manipulation
!   void reset();                                  // reset counter, but not to zero
!   void init();                                   // sets counters into original state
!   inline void set_count(int count);              // sets counter
    inline void decay();                           // decay counter (divide by two)
!   void set_carry_and_reduce();                   // set the sticky carry bit and reduce counter
!   void set_carry_if_necessary();                 // set carry if counter is big enough
!   void increment()                               { _counter += count_increment; }
  
!   // primitive read and write
!   uint raw_counter()                             { return _counter; }
! private:
!   void set_raw(uint counter)                     { _counter = counter; }
! 
!   // operate on local counter without committing to memory
!   inline void set_count(uint* counter, int count);
!   void set_carry_flag(uint* counter)             { *counter |= carry_mask; }
!   int  count(uint counter)                       { return counter >> number_of_noncount_bits; }
!   bool carry(uint counter)                       { return (counter & carry_mask) != 0; }
  
+ public:
    // Accessors
    bool  carry() const                            { return (_counter & carry_mask) != 0; }
    int   count() const                            { return _counter >> number_of_noncount_bits; }
  
    int   get_InvocationLimit() const              { return InterpreterInvocationLimit >> number_of_noncount_bits; }
    int   get_BackwardBranchLimit() const          { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; }
    int   get_ProfileLimit() const                 { return InterpreterProfileLimit >> number_of_noncount_bits; }
*** 116,156 ****
      return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >=
             (unsigned int) InterpreterProfileLimit;
    }
  #endif // CC_INTERP
  
-   void increment()                               { _counter += count_increment; }
- 
- 
    // Printing
    void   print();
    void   print_short();
  
    // Miscellaneous
    static ByteSize counter_offset()               { return byte_offset_of(InvocationCounter, _counter); }
    static void reinitialize(bool delay_overflow);
- 
-  private:
-   static int         _init  [number_of_states];  // the counter limits
-   static Action      _action[number_of_states];  // the actions
- 
-   static void        def(State state, int init, Action action);
-   static const char* state_as_string(State state);
-   static const char* state_as_short_string(State state);
  };
  
! inline void InvocationCounter::set(State state, int count) {
!   assert(0 <= state && state < number_of_states, "illegal state");
!   int carry = (_counter & carry_mask);    // the carry bit is sticky
!   _counter = (count << number_of_noncount_bits) | carry | state;
  }
  
  inline void InvocationCounter::decay() {
    int c = count();
    int new_count = c >> 1;
    // prevent from going to zero, to distinguish from never-executed methods
    if (c > 0 && new_count == 0) new_count = 1;
!   set(state(), new_count);
  }
  
- 
  #endif // SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP
--- 109,139 ----
      return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >=
             (unsigned int) InterpreterProfileLimit;
    }
  #endif // CC_INTERP
  
    // Printing
    void   print();
    void   print_short();
  
    // Miscellaneous
    static ByteSize counter_offset()               { return byte_offset_of(InvocationCounter, _counter); }
    static void reinitialize(bool delay_overflow);
  };
  
! inline void InvocationCounter::set_count(int count) {
!   _counter = (count << number_of_noncount_bits) | (_counter & carry_mask);
! }
! 
! inline void InvocationCounter::set_count(uint *counter, int count) {
!   *counter = (count << number_of_noncount_bits) | (*counter & carry_mask);
  }
  
  inline void InvocationCounter::decay() {
    int c = count();
    int new_count = c >> 1;
    // prevent from going to zero, to distinguish from never-executed methods
    if (c > 0 && new_count == 0) new_count = 1;
!   set_count(new_count);
  }
  
  #endif // SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP