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src/share/vm/interpreter/bytecodeStream.hpp@ba764ed4b6f2 (annotated)

src/share/vm/interpreter/bytecodeStream.hpp

Sun, 13 Apr 2008 17:43:42 -0400

author

coleenp

date

Sun, 13 Apr 2008 17:43:42 -0400

changeset 548

ba764ed4b6f2

parent 435

a61af66fc99e

child 1161

be93aad57795

permissions

-rw-r--r--

6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold

duke@435	1	/*
duke@435	2	* Copyright 1997-2005 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	// A BytecodeStream is used for fast iteration over the bytecodes
duke@435	26	// of a methodOop.
duke@435	27	//
duke@435	28	// Usage:
duke@435	29	//
duke@435	30	// BytecodeStream s(method);
duke@435	31	// Bytecodes::Code c;
duke@435	32	// while ((c = s.next()) >= 0) {
duke@435	33	// ...
duke@435	34	// }
duke@435	35	//
duke@435	36	// A RawBytecodeStream is a simple version of BytecodeStream.
duke@435	37	// It is used ONLY when we know the bytecodes haven't been rewritten
duke@435	38	// yet, such as in the rewriter or the verifier. Currently only the
duke@435	39	// verifier uses this class.
duke@435	40
duke@435	41	class RawBytecodeStream: StackObj {
duke@435	42	protected:
duke@435	43	// stream buffer
duke@435	44	methodHandle _method; // read from method directly
duke@435	45
duke@435	46	// reading position
duke@435	47	int _bci; // bci if current bytecode
duke@435	48	int _next_bci; // bci of next bytecode
duke@435	49	int _end_bci; // bci after the current iteration interval
duke@435	50
duke@435	51	// last bytecode read
duke@435	52	Bytecodes::Code _code;
duke@435	53	bool _is_wide;
duke@435	54
duke@435	55	public:
duke@435	56	// Construction
duke@435	57	RawBytecodeStream(methodHandle method) : _method(method) {
duke@435	58	set_interval(0, _method->code_size());
duke@435	59	}
duke@435	60
duke@435	61	// Iteration control
duke@435	62	void set_interval(int beg_bci, int end_bci) {
duke@435	63	// iterate over the interval [beg_bci, end_bci)
duke@435	64	assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci");
duke@435	65	assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci");
duke@435	66	// setup of iteration pointers
duke@435	67	_bci = beg_bci;
duke@435	68	_next_bci = beg_bci;
duke@435	69	_end_bci = end_bci;
duke@435	70	}
duke@435	71	void set_start (int beg_bci) {
duke@435	72	set_interval(beg_bci, _method->code_size());
duke@435	73	}
duke@435	74
duke@435	75	// Iteration
duke@435	76	// Use raw_next() rather than next() for faster method reference
duke@435	77	Bytecodes::Code raw_next() {
duke@435	78	Bytecodes::Code code;
duke@435	79	// set reading position
duke@435	80	_bci = _next_bci;
duke@435	81	assert(!is_last_bytecode(), "caller should check is_last_bytecode()");
duke@435	82
duke@435	83	address bcp = RawBytecodeStream::bcp();
duke@435	84	code = Bytecodes::code_or_bp_at(bcp);
duke@435	85
duke@435	86	// set next bytecode position
duke@435	87	int l = Bytecodes::length_for(code);
duke@435	88	if (l > 0 && (_bci + l) <= _end_bci) {
duke@435	89	assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch
duke@435	90	&& code != Bytecodes::_lookupswitch, "can't be special bytecode");
duke@435	91	_is_wide = false;
duke@435	92	_next_bci += l;
duke@435	93	_code = code;
duke@435	94	return code;
duke@435	95	} else if (code == Bytecodes::_wide && _bci + 1 >= _end_bci) {
duke@435	96	return Bytecodes::_illegal;
duke@435	97	} else {
duke@435	98	return raw_next_special(code);
duke@435	99	}
duke@435	100	}
duke@435	101	Bytecodes::Code raw_next_special(Bytecodes::Code code);
duke@435	102
duke@435	103	// Stream attributes
duke@435	104	methodHandle method() const { return _method; }
duke@435	105
duke@435	106	int bci() const { return _bci; }
duke@435	107	int next_bci() const { return _next_bci; }
duke@435	108	int end_bci() const { return _end_bci; }
duke@435	109
duke@435	110	Bytecodes::Code code() const { return _code; }
duke@435	111	bool is_wide() const { return _is_wide; }
duke@435	112	bool is_last_bytecode() const { return _next_bci >= _end_bci; }
duke@435	113
duke@435	114	address bcp() const { return method()->code_base() + _bci; }
duke@435	115	address next_bcp() { return method()->code_base() + _next_bci; }
duke@435	116
duke@435	117	// State changes
duke@435	118	void set_next_bci(int bci) { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; }
duke@435	119
duke@435	120	// Bytecode-specific attributes
duke@435	121	int dest() const { return bci() + (short)Bytes::get_Java_u2(bcp() + 1); }
duke@435	122	int dest_w() const { return bci() + (int )Bytes::get_Java_u4(bcp() + 1); }
duke@435	123
duke@435	124	// Unsigned indices, widening
duke@435	125	int get_index() const { return (is_wide()) ? Bytes::get_Java_u2(bcp() + 2) : bcp()[1]; }
duke@435	126	int get_index_big() const { return (int)Bytes::get_Java_u2(bcp() + 1); }
duke@435	127	};
duke@435	128
duke@435	129	// In BytecodeStream, non-java bytecodes will be translated into the
duke@435	130	// corresponding java bytecodes.
duke@435	131
duke@435	132	class BytecodeStream: public RawBytecodeStream {
duke@435	133	public:
duke@435	134	// Construction
duke@435	135	BytecodeStream(methodHandle method) : RawBytecodeStream(method) { }
duke@435	136
duke@435	137	// Iteration
duke@435	138	Bytecodes::Code next() {
duke@435	139	Bytecodes::Code code;
duke@435	140	// set reading position
duke@435	141	_bci = _next_bci;
duke@435	142	if (is_last_bytecode()) {
duke@435	143	// indicate end of bytecode stream
duke@435	144	code = Bytecodes::_illegal;
duke@435	145	} else {
duke@435	146	// get bytecode
duke@435	147	address bcp = BytecodeStream::bcp();
duke@435	148	code = Bytecodes::java_code_at(bcp);
duke@435	149	// set next bytecode position
duke@435	150	//
duke@435	151	// note that we cannot advance before having the
duke@435	152	// tty bytecode otherwise the stepping is wrong!
duke@435	153	// (carefull: length_for(...) must be used first!)
duke@435	154	int l = Bytecodes::length_for(code);
duke@435	155	if (l == 0) l = Bytecodes::length_at(bcp);
duke@435	156	_next_bci += l;
duke@435	157	assert(_bci < _next_bci, "length must be > 0");
duke@435	158	// set attributes
duke@435	159	_is_wide = false;
duke@435	160	// check for special (uncommon) cases
duke@435	161	if (code == Bytecodes::_wide) {
duke@435	162	code = (Bytecodes::Code)bcp[1];
duke@435	163	_is_wide = true;
duke@435	164	}
duke@435	165	assert(Bytecodes::is_java_code(code), "sanity check");
duke@435	166	}
duke@435	167	_code = code;
duke@435	168	return _code;
duke@435	169	}
duke@435	170
duke@435	171	bool is_active_breakpoint() const { return Bytecodes::is_active_breakpoint_at(bcp()); }
duke@435	172	};