Thu, 24 Mar 2011 02:11:50 -0700
7030207: Zero tweak to remove accidentally incorporated code
Summary: IcedTea contains a now-unmaintained ARM-specific interpreter and part of that interpreter was accidentally incorporated in one of the webrevs when Zero was initially imported.
Reviewed-by: twisti
Contributed-by: Gary Benson <gbenson@redhat.com>
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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23 */
25 #ifndef SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP
26 #define SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP
28 #include "memory/allocation.hpp"
29 #include "runtime/handles.hpp"
30 #include "utilities/exceptions.hpp"
32 // InvocationCounters are used to trigger actions when a limit (threshold) is reached.
33 // For different states, different limits and actions can be defined in the initialization
34 // routine of InvocationCounters.
35 //
36 // Implementation notes: For space reasons, state & counter are both encoded in one word,
37 // The state is encoded using some of the least significant bits, the counter is using the
38 // more significant bits. The counter is incremented before a method is activated and an
39 // action is triggered when when count() > limit().
41 class InvocationCounter VALUE_OBJ_CLASS_SPEC {
42 friend class VMStructs;
43 private: // bit no: |31 3| 2 | 1 0 |
44 unsigned int _counter; // format: [count|carry|state]
46 enum PrivateConstants {
47 number_of_state_bits = 2,
48 number_of_carry_bits = 1,
49 number_of_noncount_bits = number_of_state_bits + number_of_carry_bits,
50 number_of_count_bits = BitsPerInt - number_of_noncount_bits,
51 state_limit = nth_bit(number_of_state_bits),
52 count_grain = nth_bit(number_of_state_bits + number_of_carry_bits),
53 carry_mask = right_n_bits(number_of_carry_bits) << number_of_state_bits,
54 state_mask = right_n_bits(number_of_state_bits),
55 status_mask = right_n_bits(number_of_state_bits + number_of_carry_bits),
56 count_mask = ((int)(-1) ^ status_mask)
57 };
59 public:
60 static int InterpreterInvocationLimit; // CompileThreshold scaled for interpreter use
61 static int InterpreterBackwardBranchLimit; // A separate threshold for on stack replacement
62 static int InterpreterProfileLimit; // Profiling threshold scaled for interpreter use
64 typedef address (*Action)(methodHandle method, TRAPS);
66 enum PublicConstants {
67 count_increment = count_grain, // use this value to increment the 32bit _counter word
68 count_mask_value = count_mask, // use this value to mask the backedge counter
69 count_shift = number_of_noncount_bits,
70 count_limit = nth_bit(number_of_count_bits - 1)
71 };
73 enum State {
74 wait_for_nothing, // do nothing when count() > limit()
75 wait_for_compile, // introduce nmethod when count() > limit()
76 number_of_states // must be <= state_limit
77 };
79 // Manipulation
80 void reset(); // sets state to wait state
81 void init(); // sets state into original state
82 void set_state(State state); // sets state and initializes counter correspondingly
83 inline void set(State state, int count); // sets state and counter
84 inline void decay(); // decay counter (divide by two)
85 void set_carry(); // set the sticky carry bit
86 void set_carry_flag() { _counter |= carry_mask; }
88 // Accessors
89 State state() const { return (State)(_counter & state_mask); }
90 bool carry() const { return (_counter & carry_mask) != 0; }
91 int limit() const { return CompileThreshold; }
92 Action action() const { return _action[state()]; }
93 int count() const { return _counter >> number_of_noncount_bits; }
95 int get_InvocationLimit() const { return InterpreterInvocationLimit >> number_of_noncount_bits; }
96 int get_BackwardBranchLimit() const { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; }
97 int get_ProfileLimit() const { return InterpreterProfileLimit >> number_of_noncount_bits; }
99 // Test counter using scaled limits like the asm interpreter would do rather than doing
100 // the shifts to normalize the counter.
102 bool reached_InvocationLimit() const { return _counter >= (unsigned int) InterpreterInvocationLimit; }
103 bool reached_BackwardBranchLimit() const { return _counter >= (unsigned int) InterpreterBackwardBranchLimit; }
105 // Do this just like asm interpreter does for max speed
106 bool reached_ProfileLimit(InvocationCounter *back_edge_count) const {
107 return (_counter && count_mask) + back_edge_count->_counter >= (unsigned int) InterpreterProfileLimit;
108 }
110 void increment() { _counter += count_increment; }
113 // Printing
114 void print();
115 void print_short();
117 // Miscellaneous
118 static ByteSize counter_offset() { return byte_offset_of(InvocationCounter, _counter); }
119 static void reinitialize(bool delay_overflow);
121 private:
122 static int _init [number_of_states]; // the counter limits
123 static Action _action[number_of_states]; // the actions
125 static void def(State state, int init, Action action);
126 static const char* state_as_string(State state);
127 static const char* state_as_short_string(State state);
128 };
130 inline void InvocationCounter::set(State state, int count) {
131 assert(0 <= state && state < number_of_states, "illegal state");
132 int carry = (_counter & carry_mask); // the carry bit is sticky
133 _counter = (count << number_of_noncount_bits) | carry | state;
134 }
136 inline void InvocationCounter::decay() {
137 int c = count();
138 int new_count = c >> 1;
139 // prevent from going to zero, to distinguish from never-executed methods
140 if (c > 0 && new_count == 0) new_count = 1;
141 set(state(), new_count);
142 }
145 #endif // SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP