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src/share/vm/prims/methodComparator.hpp@f008d3631bd1 (annotated)

src/share/vm/prims/methodComparator.hpp

Wed, 08 Oct 2008 08:10:51 -0700

author

ksrini

date

Wed, 08 Oct 2008 08:10:51 -0700

changeset 823

f008d3631bd1

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6755845: JVM_FindClassFromBoot triggers assertions
Summary: Fixes assertions caused by one jvm_entry calling another, solved by refactoring code and modified gamma test.
Reviewed-by: dholmes, xlu

duke@435	1	/*
duke@435	2	* Copyright 2000-2005 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	class BciMap;
duke@435	26
duke@435	27	// methodComparator provides an interface for determining if methods of
duke@435	28	// different versions of classes are equivalent or switchable
duke@435	29
duke@435	30	class MethodComparator {
duke@435	31	private:
duke@435	32	static BytecodeStream *_s_old, *_s_new;
duke@435	33	static constantPoolOop _old_cp, _new_cp;
duke@435	34	static BciMap *_bci_map;
duke@435	35	static bool _switchable_test;
duke@435	36	static GrowableArray<int> *_fwd_jmps;
duke@435	37
duke@435	38	static bool args_same(Bytecodes::Code c_old, Bytecodes::Code c_new);
duke@435	39	static int check_stack_and_locals_size(methodOop old_method, methodOop new_method);
duke@435	40
duke@435	41	public:
duke@435	42	// Check if the new method is equivalent to the old one modulo constant pool (EMCP).
duke@435	43	// Intuitive definition: two versions of the same method are EMCP, if they don't differ
duke@435	44	// on the source code level. Practically, we check whether the only difference between
duke@435	45	// method versions is some constantpool indices embedded into the bytecodes, and whether
duke@435	46	// these indices eventually point to the same constants for both method versions.
duke@435	47	static bool methods_EMCP(methodOop old_method, methodOop new_method);
duke@435	48
duke@435	49	static bool methods_switchable(methodOop old_method, methodOop new_method, BciMap &bci_map);
duke@435	50	};
duke@435	51
duke@435	52
duke@435	53	// ByteCode Index Map. For two versions of the same method, where the new version may contain
duke@435	54	// fragments not found in the old version, provides a mapping from an index of a bytecode in
duke@435	55	// the old method to the index of the same bytecode in the new method.
duke@435	56
duke@435	57	class BciMap {
duke@435	58	private:
duke@435	59	int *_old_bci, *_new_st_bci, *_new_end_bci;
duke@435	60	int _cur_size, _cur_pos;
duke@435	61	int _pos;
duke@435	62
duke@435	63	public:
duke@435	64	BciMap() {
duke@435	65	_cur_size = 50;
duke@435	66	_old_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435	67	_new_st_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435	68	_new_end_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435	69	_cur_pos = 0;
duke@435	70	}
duke@435	71
duke@435	72	~BciMap() {
duke@435	73	free(_old_bci);
duke@435	74	free(_new_st_bci);
duke@435	75	free(_new_end_bci);
duke@435	76	}
duke@435	77
duke@435	78	// Store the position of an added fragment, e.g.
duke@435	79	//
duke@435	80	// |<- old_bci
duke@435	81	// -----------------------------------------
duke@435	82	// Old method |invokevirtual 5|aload 1|...
duke@435	83	// -----------------------------------------
duke@435	84	//
duke@435	85	// |<- new_st_bci |<- new_end_bci
duke@435	86	// --------------------------------------------------------------------
duke@435	87	// New method |invokevirual 5|aload 2|invokevirtual 6|aload 1|...
duke@435	88	// --------------------------------------------------------------------
duke@435	89	// ^^^^^^^^^^^^^^^^^^^^^^^^
duke@435	90	// Added fragment
duke@435	91
duke@435	92	void store_fragment_location(int old_bci, int new_st_bci, int new_end_bci) {
duke@435	93	if (_cur_pos == _cur_size) {
duke@435	94	_cur_size += 10;
duke@435	95	_old_bci = (int*) realloc(_old_bci, sizeof(int) * _cur_size);
duke@435	96	_new_st_bci = (int*) realloc(_new_st_bci, sizeof(int) * _cur_size);
duke@435	97	_new_end_bci = (int*) realloc(_new_end_bci, sizeof(int) * _cur_size);
duke@435	98	}
duke@435	99	_old_bci[_cur_pos] = old_bci;
duke@435	100	_new_st_bci[_cur_pos] = new_st_bci;
duke@435	101	_new_end_bci[_cur_pos] = new_end_bci;
duke@435	102	_cur_pos++;
duke@435	103	}
duke@435	104
duke@435	105	int new_bci_for_old(int old_bci) {
duke@435	106	if (_cur_pos == 0 || old_bci < _old_bci[0]) return old_bci;
duke@435	107	_pos = 1;
duke@435	108	while (_pos < _cur_pos && old_bci >= _old_bci[_pos])
duke@435	109	_pos++;
duke@435	110	return _new_end_bci[_pos-1] + (old_bci - _old_bci[_pos-1]);
duke@435	111	}
duke@435	112
duke@435	113	// Test if two indexes - one in the old method and another in the new one - correspond
duke@435	114	// to the same bytecode
duke@435	115	bool old_and_new_locations_same(int old_dest_bci, int new_dest_bci) {
duke@435	116	if (new_bci_for_old(old_dest_bci) == new_dest_bci)
duke@435	117	return true;
duke@435	118	else if (_old_bci[_pos-1] == old_dest_bci)
duke@435	119	return (new_dest_bci == _new_st_bci[_pos-1]);
duke@435	120	else return false;
duke@435	121	}
duke@435	122	};