1 /* 2 * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 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). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_INTERPRETER_INVOCATIONCOUNTER_HPP 26 #define SHARE_INTERPRETER_INVOCATIONCOUNTER_HPP 27 28 #include "runtime/handles.hpp" 29 #include "utilities/exceptions.hpp" 30 31 // InvocationCounters are used to trigger actions when a limit (threshold) is reached. 32 // 33 // The counter is incremented before a method is activated and an 34 // action is triggered when count() > limit(). 35 36 class InvocationCounter { 37 friend class VMStructs; 38 friend class JVMCIVMStructs; 39 friend class ciReplay; 40 private: // bit no: |31 1| 0 | 41 uint _counter; // format: [count|carry| 42 43 enum PrivateConstants { 44 number_of_carry_bits = 1, 45 number_of_noncount_bits = number_of_carry_bits, 46 count_grain = nth_bit(number_of_carry_bits), 47 carry_mask = right_n_bits(number_of_carry_bits), 48 count_mask = ((int)(-1) ^ carry_mask) 49 }; 50 51 public: 52 enum PublicConstants { 53 count_increment = count_grain, // use this value to increment the 32bit _counter word 54 count_mask_value = count_mask, // use this value to mask the backedge counter 55 count_shift = number_of_noncount_bits, 56 number_of_count_bits = BitsPerInt - number_of_noncount_bits, 57 count_limit = nth_bit(number_of_count_bits - 1) 58 }; 59 60 // Manipulation 61 void reset(); 62 void init(); 63 void decay(); // decay counter (divide by two) 64 void set_carry_on_overflow(); 65 void set(uint count); increment()66 void increment() { _counter += count_increment; } 67 68 // Accessors carry() const69 bool carry() const { return (_counter & carry_mask) != 0; } count() const70 uint count() const { return _counter >> number_of_noncount_bits; } limit() const71 uint limit() const { return CompileThreshold; } raw_counter() const72 uint raw_counter() const { return _counter; } 73 74 void print(); 75 76 private: set_carry()77 void set_carry() { _counter |= carry_mask; } extract_carry(uint raw) const78 uint extract_carry(uint raw) const { return (raw & carry_mask); } extract_count(uint raw) const79 uint extract_count(uint raw) const { return raw >> number_of_noncount_bits; } 80 void update(uint new_count); 81 void set(uint count, uint carry); 82 83 public: 84 85 // Miscellaneous counter_offset()86 static ByteSize counter_offset() { return byte_offset_of(InvocationCounter, _counter); } 87 }; 88 89 #endif // SHARE_INTERPRETER_INVOCATIONCOUNTER_HPP 90