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src/share/vm/interpreter/invocationCounter.hpp@c7ec737733a6 (annotated)

src/share/vm/interpreter/invocationCounter.hpp

Thu, 30 Oct 2008 15:48:59 -0400

author

kamg

date

Thu, 30 Oct 2008 15:48:59 -0400

changeset 848

c7ec737733a6

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6756528: Bytecodes::special_length_at reads past end of code buffer
Summary: Add end-of-buffer indicator for paths used by the verifier
Reviewed-by: acorn, coleenp

duke@435	1	/*
duke@435	2	* Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// InvocationCounters are used to trigger actions when a limit (threshold) is reached.
duke@435	26	// For different states, different limits and actions can be defined in the initialization
duke@435	27	// routine of InvocationCounters.
duke@435	28	//
duke@435	29	// Implementation notes: For space reasons, state & counter are both encoded in one word,
duke@435	30	// The state is encoded using some of the least significant bits, the counter is using the
duke@435	31	// more significant bits. The counter is incremented before a method is activated and an
duke@435	32	// action is triggered when when count() > limit().
duke@435	33
duke@435	34	class InvocationCounter VALUE_OBJ_CLASS_SPEC {
duke@435	35	friend class VMStructs;
duke@435	36	private: // bit no: |31 3| 2 | 1 0 |
duke@435	37	unsigned int _counter; // format: [count|carry|state]
duke@435	38
duke@435	39	enum PrivateConstants {
duke@435	40	number_of_state_bits = 2,
duke@435	41	number_of_carry_bits = 1,
duke@435	42	number_of_noncount_bits = number_of_state_bits + number_of_carry_bits,
duke@435	43	number_of_count_bits = BitsPerInt - number_of_noncount_bits,
duke@435	44	state_limit = nth_bit(number_of_state_bits),
duke@435	45	count_grain = nth_bit(number_of_state_bits + number_of_carry_bits),
duke@435	46	count_limit = nth_bit(number_of_count_bits - 1),
duke@435	47	carry_mask = right_n_bits(number_of_carry_bits) << number_of_state_bits,
duke@435	48	state_mask = right_n_bits(number_of_state_bits),
duke@435	49	status_mask = right_n_bits(number_of_state_bits + number_of_carry_bits),
duke@435	50	count_mask = ((int)(-1) ^ status_mask)
duke@435	51	};
duke@435	52
duke@435	53	public:
duke@435	54	static int InterpreterInvocationLimit; // CompileThreshold scaled for interpreter use
duke@435	55	static int Tier1InvocationLimit; // CompileThreshold scaled for tier1 use
duke@435	56	static int Tier1BackEdgeLimit; // BackEdgeThreshold scaled for tier1 use
duke@435	57
duke@435	58	static int InterpreterBackwardBranchLimit; // A separate threshold for on stack replacement
duke@435	59
duke@435	60	static int InterpreterProfileLimit; // Profiling threshold scaled for interpreter use
duke@435	61
duke@435	62	typedef address (*Action)(methodHandle method, TRAPS);
duke@435	63
duke@435	64	enum PublicConstants {
duke@435	65	count_increment = count_grain, // use this value to increment the 32bit _counter word
duke@435	66	count_mask_value = count_mask // use this value to mask the backedge counter
duke@435	67	};
duke@435	68
duke@435	69	enum State {
duke@435	70	wait_for_nothing, // do nothing when count() > limit()
duke@435	71	wait_for_compile, // introduce nmethod when count() > limit()
duke@435	72	number_of_states // must be <= state_limit
duke@435	73	};
duke@435	74
duke@435	75	// Manipulation
duke@435	76	void reset(); // sets state to wait state
duke@435	77	void init(); // sets state into original state
duke@435	78	void set_state(State state); // sets state and initializes counter correspondingly
duke@435	79	inline void set(State state, int count); // sets state and counter
duke@435	80	inline void decay(); // decay counter (divide by two)
duke@435	81	void set_carry(); // set the sticky carry bit
duke@435	82
duke@435	83	// Accessors
duke@435	84	State state() const { return (State)(_counter & state_mask); }
duke@435	85	bool carry() const { return (_counter & carry_mask) != 0; }
duke@435	86	int limit() const { return CompileThreshold; }
duke@435	87	Action action() const { return _action[state()]; }
duke@435	88	int count() const { return _counter >> number_of_noncount_bits; }
duke@435	89
duke@435	90	int get_InvocationLimit() const { return InterpreterInvocationLimit >> number_of_noncount_bits; }
duke@435	91	int get_BackwardBranchLimit() const { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; }
duke@435	92	int get_ProfileLimit() const { return InterpreterProfileLimit >> number_of_noncount_bits; }
duke@435	93
duke@435	94	// Test counter using scaled limits like the asm interpreter would do rather than doing
duke@435	95	// the shifts to normalize the counter.
duke@435	96
duke@435	97	bool reached_InvocationLimit() const { return _counter >= (unsigned int) InterpreterInvocationLimit; }
duke@435	98	bool reached_BackwardBranchLimit() const { return _counter >= (unsigned int) InterpreterBackwardBranchLimit; }
duke@435	99
duke@435	100	// Do this just like asm interpreter does for max speed
duke@435	101	bool reached_ProfileLimit(InvocationCounter *back_edge_count) const {
duke@435	102	return (_counter && count_mask) + back_edge_count->_counter >= (unsigned int) InterpreterProfileLimit;
duke@435	103	}
duke@435	104
duke@435	105	void increment() { _counter += count_increment; }
duke@435	106
duke@435	107
duke@435	108	// Printing
duke@435	109	void print();
duke@435	110	void print_short();
duke@435	111
duke@435	112	// Miscellaneous
duke@435	113	static ByteSize counter_offset() { return byte_offset_of(InvocationCounter, _counter); }
duke@435	114	static void reinitialize(bool delay_overflow);
duke@435	115
duke@435	116	private:
duke@435	117	static int _init [number_of_states]; // the counter limits
duke@435	118	static Action _action[number_of_states]; // the actions
duke@435	119
duke@435	120	static void def(State state, int init, Action action);
duke@435	121	static const char* state_as_string(State state);
duke@435	122	static const char* state_as_short_string(State state);
duke@435	123	};
duke@435	124
duke@435	125	inline void InvocationCounter::set(State state, int count) {
duke@435	126	assert(0 <= state && state < number_of_states, "illegal state");
duke@435	127	int carry = (_counter & carry_mask); // the carry bit is sticky
duke@435	128	_counter = (count << number_of_noncount_bits) | carry | state;
duke@435	129	}
duke@435	130
duke@435	131	inline void InvocationCounter::decay() {
duke@435	132	int c = count();
duke@435	133	int new_count = c >> 1;
duke@435	134	// prevent from going to zero, to distinguish from never-executed methods
duke@435	135	if (c > 0 && new_count == 0) new_count = 1;
duke@435	136	set(state(), new_count);
duke@435	137	}