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src/share/vm/prims/methodComparator.hpp@eef07cd490d4 (annotated)

src/share/vm/prims/methodComparator.hpp

Wed, 03 Jul 2019 20:42:37 +0800

author

aoqi

date

Wed, 03 Jul 2019 20:42:37 +0800

changeset 9637

eef07cd490d4

parent 6876

710a3c8b516e

permissions

-rw-r--r--

Merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_PRIMS_METHODCOMPARATOR_HPP
aoqi@0	26	#define SHARE_VM_PRIMS_METHODCOMPARATOR_HPP
aoqi@0	27
aoqi@0	28	#include "interpreter/bytecodeStream.hpp"
aoqi@0	29	#include "oops/constantPool.hpp"
aoqi@0	30	#include "oops/method.hpp"
aoqi@0	31
aoqi@0	32	class BciMap;
aoqi@0	33
aoqi@0	34	// methodComparator provides an interface for determining if methods of
aoqi@0	35	// different versions of classes are equivalent or switchable
aoqi@0	36
aoqi@0	37	class MethodComparator {
aoqi@0	38	private:
aoqi@0	39	static BytecodeStream *_s_old, *_s_new;
aoqi@0	40	static ConstantPool* _old_cp;
aoqi@0	41	static ConstantPool* _new_cp;
aoqi@0	42	static BciMap *_bci_map;
aoqi@0	43	static bool _switchable_test;
aoqi@0	44	static GrowableArray<int> *_fwd_jmps;
aoqi@0	45
aoqi@0	46	static bool args_same(Bytecodes::Code c_old, Bytecodes::Code c_new);
aoqi@0	47	static bool pool_constants_same(int cpi_old, int cpi_new);
aoqi@0	48	static int check_stack_and_locals_size(Method* old_method, Method* new_method);
aoqi@0	49
aoqi@0	50	public:
aoqi@0	51	// Check if the new method is equivalent to the old one modulo constant pool (EMCP).
aoqi@0	52	// Intuitive definition: two versions of the same method are EMCP, if they don't differ
aoqi@0	53	// on the source code level. Practically, we check whether the only difference between
aoqi@0	54	// method versions is some constantpool indices embedded into the bytecodes, and whether
aoqi@0	55	// these indices eventually point to the same constants for both method versions.
aoqi@0	56	static bool methods_EMCP(Method* old_method, Method* new_method);
aoqi@0	57
aoqi@0	58	static bool methods_switchable(Method* old_method, Method* new_method, BciMap &bci_map);
aoqi@0	59	};
aoqi@0	60
aoqi@0	61
aoqi@0	62	// ByteCode Index Map. For two versions of the same method, where the new version may contain
aoqi@0	63	// fragments not found in the old version, provides a mapping from an index of a bytecode in
aoqi@0	64	// the old method to the index of the same bytecode in the new method.
aoqi@0	65
aoqi@0	66	class BciMap {
aoqi@0	67	private:
aoqi@0	68	int *_old_bci, *_new_st_bci, *_new_end_bci;
aoqi@0	69	int _cur_size, _cur_pos;
aoqi@0	70	int _pos;
aoqi@0	71
aoqi@0	72	public:
aoqi@0	73	BciMap() {
aoqi@0	74	_cur_size = 50;
aoqi@0	75	_old_bci = (int*) malloc(sizeof(int) * _cur_size);
aoqi@0	76	_new_st_bci = (int*) malloc(sizeof(int) * _cur_size);
aoqi@0	77	_new_end_bci = (int*) malloc(sizeof(int) * _cur_size);
aoqi@0	78	_cur_pos = 0;
aoqi@0	79	}
aoqi@0	80
aoqi@0	81	~BciMap() {
aoqi@0	82	free(_old_bci);
aoqi@0	83	free(_new_st_bci);
aoqi@0	84	free(_new_end_bci);
aoqi@0	85	}
aoqi@0	86
aoqi@0	87	// Store the position of an added fragment, e.g.
aoqi@0	88	//
aoqi@0	89	// |<- old_bci
aoqi@0	90	// -----------------------------------------
aoqi@0	91	// Old method |invokevirtual 5|aload 1|...
aoqi@0	92	// -----------------------------------------
aoqi@0	93	//
aoqi@0	94	// |<- new_st_bci |<- new_end_bci
aoqi@0	95	// --------------------------------------------------------------------
aoqi@0	96	// New method |invokevirual 5|aload 2|invokevirtual 6|aload 1|...
aoqi@0	97	// --------------------------------------------------------------------
aoqi@0	98	// ^^^^^^^^^^^^^^^^^^^^^^^^
aoqi@0	99	// Added fragment
aoqi@0	100
aoqi@0	101	void store_fragment_location(int old_bci, int new_st_bci, int new_end_bci) {
aoqi@0	102	if (_cur_pos == _cur_size) {
aoqi@0	103	_cur_size += 10;
aoqi@0	104	_old_bci = (int*) realloc(_old_bci, sizeof(int) * _cur_size);
aoqi@0	105	_new_st_bci = (int*) realloc(_new_st_bci, sizeof(int) * _cur_size);
aoqi@0	106	_new_end_bci = (int*) realloc(_new_end_bci, sizeof(int) * _cur_size);
aoqi@0	107	}
aoqi@0	108	_old_bci[_cur_pos] = old_bci;
aoqi@0	109	_new_st_bci[_cur_pos] = new_st_bci;
aoqi@0	110	_new_end_bci[_cur_pos] = new_end_bci;
aoqi@0	111	_cur_pos++;
aoqi@0	112	}
aoqi@0	113
aoqi@0	114	int new_bci_for_old(int old_bci) {
aoqi@0	115	if (_cur_pos == 0 || old_bci < _old_bci[0]) return old_bci;
aoqi@0	116	_pos = 1;
aoqi@0	117	while (_pos < _cur_pos && old_bci >= _old_bci[_pos])
aoqi@0	118	_pos++;
aoqi@0	119	return _new_end_bci[_pos-1] + (old_bci - _old_bci[_pos-1]);
aoqi@0	120	}
aoqi@0	121
aoqi@0	122	// Test if two indexes - one in the old method and another in the new one - correspond
aoqi@0	123	// to the same bytecode
aoqi@0	124	bool old_and_new_locations_same(int old_dest_bci, int new_dest_bci) {
aoqi@0	125	if (new_bci_for_old(old_dest_bci) == new_dest_bci)
aoqi@0	126	return true;
aoqi@0	127	else if (_old_bci[_pos-1] == old_dest_bci)
aoqi@0	128	return (new_dest_bci == _new_st_bci[_pos-1]);
aoqi@0	129	else return false;
aoqi@0	130	}
aoqi@0	131	};
aoqi@0	132
aoqi@0	133	#endif // SHARE_VM_PRIMS_METHODCOMPARATOR_HPP