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src/share/vm/compiler/methodLiveness.cpp@c18cbe5936b8 (annotated)

src/share/vm/compiler/methodLiveness.cpp

Thu, 27 May 2010 19:08:38 -0700

author

trims

date

Thu, 27 May 2010 19:08:38 -0700

changeset 1907

c18cbe5936b8

parent 1570

e66fd840cb6b

child 2314

f95d63e2154a

permissions

-rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

duke@435	1	/*
trims@1907	2	* Copyright (c) 1998, 2006, Oracle and/or its affiliates. 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	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// The MethodLiveness class performs a simple liveness analysis on a method
duke@435	26	// in order to decide which locals are live (that is, will be used again) at
duke@435	27	// a particular bytecode index (bci).
duke@435	28	//
duke@435	29	// The algorithm goes:
duke@435	30	//
duke@435	31	// 1. Break the method into a set of basic blocks. For each basic block we
duke@435	32	// also keep track of its set of predecessors through normal control flow
duke@435	33	// and predecessors through exceptional control flow.
duke@435	34	//
duke@435	35	// 2. For each basic block, compute two sets, gen (the set of values used before
duke@435	36	// they are defined) and kill (the set of values defined before they are used)
duke@435	37	// in the basic block. A basic block "needs" the locals in its gen set to
duke@435	38	// perform its computation. A basic block "provides" values for the locals in
duke@435	39	// its kill set, allowing a need from a successor to be ignored.
duke@435	40	//
duke@435	41	// 3. Liveness information (the set of locals which are needed) is pushed backwards through
duke@435	42	// the program, from blocks to their predecessors. We compute and store liveness
duke@435	43	// information for the normal/exceptional exit paths for each basic block. When
duke@435	44	// this process reaches a fixed point, we are done.
duke@435	45	//
duke@435	46	// 4. When we are asked about the liveness at a particular bci with a basic block, we
duke@435	47	// compute gen/kill sets which represent execution from that bci to the exit of
duke@435	48	// its blocks. We then compose this range gen/kill information with the normal
duke@435	49	// and exceptional exit information for the block to produce liveness information
duke@435	50	// at that bci.
duke@435	51	//
duke@435	52	// The algorithm is approximate in many respects. Notably:
duke@435	53	//
duke@435	54	// 1. We do not do the analysis necessary to match jsr's with the appropriate ret.
duke@435	55	// Instead we make the conservative assumption that any ret can return to any
duke@435	56	// jsr return site.
duke@435	57	// 2. Instead of computing the effects of exceptions at every instruction, we
duke@435	58	// summarize the effects of all exceptional continuations from the block as
duke@435	59	// a single set (_exception_exit), losing some information but simplifying the
duke@435	60	// analysis.
duke@435	61
duke@435	62
duke@435	63	# include "incls/_precompiled.incl"
duke@435	64	# include "incls/_methodLiveness.cpp.incl"
duke@435	65
duke@435	66	//--------------------------------------------------------------------------
duke@435	67	// The BitCounter class is used for counting the number of bits set in
duke@435	68	// some BitMap. It is only used when collecting liveness statistics.
duke@435	69
duke@435	70	#ifndef PRODUCT
duke@435	71
duke@435	72	class BitCounter: public BitMapClosure {
duke@435	73	private:
duke@435	74	int _count;
duke@435	75	public:
duke@435	76	BitCounter() : _count(0) {}
duke@435	77
duke@435	78	// Callback when bit in map is set
ysr@777	79	virtual bool do_bit(size_t offset) {
duke@435	80	_count++;
ysr@777	81	return true;
duke@435	82	}
duke@435	83
duke@435	84	int count() {
duke@435	85	return _count;
duke@435	86	}
duke@435	87	};
duke@435	88
duke@435	89
duke@435	90	//--------------------------------------------------------------------------
duke@435	91
duke@435	92
duke@435	93	// Counts
duke@435	94	long MethodLiveness::_total_bytes = 0;
duke@435	95	int MethodLiveness::_total_methods = 0;
duke@435	96
duke@435	97	long MethodLiveness::_total_blocks = 0;
duke@435	98	int MethodLiveness::_max_method_blocks = 0;
duke@435	99
duke@435	100	long MethodLiveness::_total_edges = 0;
duke@435	101	int MethodLiveness::_max_block_edges = 0;
duke@435	102
duke@435	103	long MethodLiveness::_total_exc_edges = 0;
duke@435	104	int MethodLiveness::_max_block_exc_edges = 0;
duke@435	105
duke@435	106	long MethodLiveness::_total_method_locals = 0;
duke@435	107	int MethodLiveness::_max_method_locals = 0;
duke@435	108
duke@435	109	long MethodLiveness::_total_locals_queried = 0;
duke@435	110	long MethodLiveness::_total_live_locals_queried = 0;
duke@435	111
duke@435	112	long MethodLiveness::_total_visits = 0;
duke@435	113
duke@435	114	#endif
duke@435	115
duke@435	116	// Timers
duke@435	117	elapsedTimer MethodLiveness::_time_build_graph;
duke@435	118	elapsedTimer MethodLiveness::_time_gen_kill;
duke@435	119	elapsedTimer MethodLiveness::_time_flow;
duke@435	120	elapsedTimer MethodLiveness::_time_query;
duke@435	121	elapsedTimer MethodLiveness::_time_total;
duke@435	122
duke@435	123	MethodLiveness::MethodLiveness(Arena* arena, ciMethod* method)
duke@435	124	#ifdef COMPILER1
duke@435	125	: _bci_block_start((uintptr_t*)arena->Amalloc((method->code_size() >> LogBitsPerByte) + 1), method->code_size())
duke@435	126	#endif
duke@435	127	{
duke@435	128	_arena = arena;
duke@435	129	_method = method;
duke@435	130	_bit_map_size_bits = method->max_locals();
duke@435	131	_bit_map_size_words = (_bit_map_size_bits / sizeof(unsigned int)) + 1;
duke@435	132
duke@435	133	#ifdef COMPILER1
duke@435	134	_bci_block_start.clear();
duke@435	135	#endif
duke@435	136	}
duke@435	137
duke@435	138	void MethodLiveness::compute_liveness() {
duke@435	139	#ifndef PRODUCT
duke@435	140	if (TraceLivenessGen) {
duke@435	141	tty->print_cr("################################################################");
duke@435	142	tty->print("# Computing liveness information for ");
duke@435	143	method()->print_short_name();
duke@435	144	}
duke@435	145
duke@435	146	if (TimeLivenessAnalysis) _time_total.start();
duke@435	147	#endif
duke@435	148
duke@435	149	{
duke@435	150	TraceTime buildGraph(NULL, &_time_build_graph, TimeLivenessAnalysis);
duke@435	151	init_basic_blocks();
duke@435	152	}
duke@435	153	{
duke@435	154	TraceTime genKill(NULL, &_time_gen_kill, TimeLivenessAnalysis);
duke@435	155	init_gen_kill();
duke@435	156	}
duke@435	157	{
duke@435	158	TraceTime flow(NULL, &_time_flow, TimeLivenessAnalysis);
duke@435	159	propagate_liveness();
duke@435	160	}
duke@435	161
duke@435	162	#ifndef PRODUCT
duke@435	163	if (TimeLivenessAnalysis) _time_total.stop();
duke@435	164
duke@435	165	if (TimeLivenessAnalysis) {
duke@435	166	// Collect statistics
duke@435	167	_total_bytes += method()->code_size();
duke@435	168	_total_methods++;
duke@435	169
duke@435	170	int num_blocks = _block_count;
duke@435	171	_total_blocks += num_blocks;
duke@435	172	_max_method_blocks = MAX2(num_blocks,_max_method_blocks);
duke@435	173
duke@435	174	for (int i=0; i<num_blocks; i++) {
duke@435	175	BasicBlock *block = _block_list[i];
duke@435	176
duke@435	177	int numEdges = block->_normal_predecessors->length();
duke@435	178	int numExcEdges = block->_exception_predecessors->length();
duke@435	179
duke@435	180	_total_edges += numEdges;
duke@435	181	_total_exc_edges += numExcEdges;
duke@435	182	_max_block_edges = MAX2(numEdges,_max_block_edges);
duke@435	183	_max_block_exc_edges = MAX2(numExcEdges,_max_block_exc_edges);
duke@435	184	}
duke@435	185
duke@435	186	int numLocals = _bit_map_size_bits;
duke@435	187	_total_method_locals += numLocals;
duke@435	188	_max_method_locals = MAX2(numLocals,_max_method_locals);
duke@435	189	}
duke@435	190	#endif
duke@435	191	}
duke@435	192
duke@435	193
duke@435	194	void MethodLiveness::init_basic_blocks() {
duke@435	195	bool bailout = false;
duke@435	196
duke@435	197	int method_len = method()->code_size();
duke@435	198	ciMethodBlocks *mblocks = method()->get_method_blocks();
duke@435	199
duke@435	200	// Create an array to store the bci->BasicBlock mapping.
duke@435	201	_block_map = new (arena()) GrowableArray<BasicBlock*>(arena(), method_len, method_len, NULL);
duke@435	202
duke@435	203	_block_count = mblocks->num_blocks();
duke@435	204	_block_list = (BasicBlock **) arena()->Amalloc(sizeof(BasicBlock *) * _block_count);
duke@435	205
duke@435	206	// Used for patching up jsr/ret control flow.
duke@435	207	GrowableArray<BasicBlock*>* jsr_exit_list = new GrowableArray<BasicBlock*>(5);
duke@435	208	GrowableArray<BasicBlock*>* ret_list = new GrowableArray<BasicBlock*>(5);
duke@435	209
duke@435	210	// generate our block list from ciMethodBlocks
duke@435	211	for (int blk = 0; blk < _block_count; blk++) {
duke@435	212	ciBlock *cib = mblocks->block(blk);
duke@435	213	int start_bci = cib->start_bci();
duke@435	214	_block_list[blk] = new (arena()) BasicBlock(this, start_bci, cib->limit_bci());
duke@435	215	_block_map->at_put(start_bci, _block_list[blk]);
duke@435	216	#ifdef COMPILER1
duke@435	217	// mark all bcis where a new basic block starts
duke@435	218	_bci_block_start.set_bit(start_bci);
duke@435	219	#endif // COMPILER1
duke@435	220	}
duke@435	221	// fill in the predecessors of blocks
duke@435	222	ciBytecodeStream bytes(method());
duke@435	223
duke@435	224	for (int blk = 0; blk < _block_count; blk++) {
duke@435	225	BasicBlock *current_block = _block_list[blk];
duke@435	226	int bci = mblocks->block(blk)->control_bci();
duke@435	227
duke@435	228	if (bci == ciBlock::fall_through_bci) {
duke@435	229	int limit = current_block->limit_bci();
duke@435	230	if (limit < method_len) {
duke@435	231	BasicBlock *next = _block_map->at(limit);
duke@435	232	assert( next != NULL, "must be a block immediately following this one.");
duke@435	233	next->add_normal_predecessor(current_block);
duke@435	234	}
duke@435	235	continue;
duke@435	236	}
duke@435	237	bytes.reset_to_bci(bci);
duke@435	238	Bytecodes::Code code = bytes.next();
duke@435	239	BasicBlock *dest;
duke@435	240
duke@435	241	// Now we need to interpret the instruction's effect
duke@435	242	// on control flow.
duke@435	243	assert (current_block != NULL, "we must have a current block");
duke@435	244	switch (code) {
duke@435	245	case Bytecodes::_ifeq:
duke@435	246	case Bytecodes::_ifne:
duke@435	247	case Bytecodes::_iflt:
duke@435	248	case Bytecodes::_ifge:
duke@435	249	case Bytecodes::_ifgt:
duke@435	250	case Bytecodes::_ifle:
duke@435	251	case Bytecodes::_if_icmpeq:
duke@435	252	case Bytecodes::_if_icmpne:
duke@435	253	case Bytecodes::_if_icmplt:
duke@435	254	case Bytecodes::_if_icmpge:
duke@435	255	case Bytecodes::_if_icmpgt:
duke@435	256	case Bytecodes::_if_icmple:
duke@435	257	case Bytecodes::_if_acmpeq:
duke@435	258	case Bytecodes::_if_acmpne:
duke@435	259	case Bytecodes::_ifnull:
duke@435	260	case Bytecodes::_ifnonnull:
duke@435	261	// Two way branch. Set predecessors at each destination.
duke@435	262	dest = _block_map->at(bytes.next_bci());
duke@435	263	assert(dest != NULL, "must be a block immediately following this one.");
duke@435	264	dest->add_normal_predecessor(current_block);
duke@435	265
duke@435	266	dest = _block_map->at(bytes.get_dest());
duke@435	267	assert(dest != NULL, "branch desination must start a block.");
duke@435	268	dest->add_normal_predecessor(current_block);
duke@435	269	break;
duke@435	270	case Bytecodes::_goto:
duke@435	271	dest = _block_map->at(bytes.get_dest());
duke@435	272	assert(dest != NULL, "branch desination must start a block.");
duke@435	273	dest->add_normal_predecessor(current_block);
duke@435	274	break;
duke@435	275	case Bytecodes::_goto_w:
duke@435	276	dest = _block_map->at(bytes.get_far_dest());
duke@435	277	assert(dest != NULL, "branch desination must start a block.");
duke@435	278	dest->add_normal_predecessor(current_block);
duke@435	279	break;
duke@435	280	case Bytecodes::_tableswitch:
duke@435	281	{
duke@435	282	Bytecode_tableswitch *tableswitch =
duke@435	283	Bytecode_tableswitch_at(bytes.cur_bcp());
duke@435	284
duke@435	285	int len = tableswitch->length();
duke@435	286
duke@435	287	dest = _block_map->at(bci + tableswitch->default_offset());
duke@435	288	assert(dest != NULL, "branch desination must start a block.");
duke@435	289	dest->add_normal_predecessor(current_block);
duke@435	290	while (--len >= 0) {
duke@435	291	dest = _block_map->at(bci + tableswitch->dest_offset_at(len));
duke@435	292	assert(dest != NULL, "branch desination must start a block.");
duke@435	293	dest->add_normal_predecessor(current_block);
duke@435	294	}
duke@435	295	break;
duke@435	296	}
duke@435	297
duke@435	298	case Bytecodes::_lookupswitch:
duke@435	299	{
duke@435	300	Bytecode_lookupswitch *lookupswitch =
duke@435	301	Bytecode_lookupswitch_at(bytes.cur_bcp());
duke@435	302
duke@435	303	int npairs = lookupswitch->number_of_pairs();
duke@435	304
duke@435	305	dest = _block_map->at(bci + lookupswitch->default_offset());
duke@435	306	assert(dest != NULL, "branch desination must start a block.");
duke@435	307	dest->add_normal_predecessor(current_block);
duke@435	308	while(--npairs >= 0) {
duke@435	309	LookupswitchPair *pair = lookupswitch->pair_at(npairs);
duke@435	310	dest = _block_map->at( bci + pair->offset());
duke@435	311	assert(dest != NULL, "branch desination must start a block.");
duke@435	312	dest->add_normal_predecessor(current_block);
duke@435	313	}
duke@435	314	break;
duke@435	315	}
duke@435	316
duke@435	317	case Bytecodes::_jsr:
duke@435	318	{
duke@435	319	assert(bytes.is_wide()==false, "sanity check");
duke@435	320	dest = _block_map->at(bytes.get_dest());
duke@435	321	assert(dest != NULL, "branch desination must start a block.");
duke@435	322	dest->add_normal_predecessor(current_block);
duke@435	323	BasicBlock *jsrExit = _block_map->at(current_block->limit_bci());
duke@435	324	assert(jsrExit != NULL, "jsr return bci must start a block.");
duke@435	325	jsr_exit_list->append(jsrExit);
duke@435	326	break;
duke@435	327	}
duke@435	328	case Bytecodes::_jsr_w:
duke@435	329	{
duke@435	330	dest = _block_map->at(bytes.get_far_dest());
duke@435	331	assert(dest != NULL, "branch desination must start a block.");
duke@435	332	dest->add_normal_predecessor(current_block);
duke@435	333	BasicBlock *jsrExit = _block_map->at(current_block->limit_bci());
duke@435	334	assert(jsrExit != NULL, "jsr return bci must start a block.");
duke@435	335	jsr_exit_list->append(jsrExit);
duke@435	336	break;
duke@435	337	}
duke@435	338
duke@435	339	case Bytecodes::_wide:
duke@435	340	assert(false, "wide opcodes should not be seen here");
duke@435	341	break;
duke@435	342	case Bytecodes::_athrow:
duke@435	343	case Bytecodes::_ireturn:
duke@435	344	case Bytecodes::_lreturn:
duke@435	345	case Bytecodes::_freturn:
duke@435	346	case Bytecodes::_dreturn:
duke@435	347	case Bytecodes::_areturn:
duke@435	348	case Bytecodes::_return:
duke@435	349	// These opcodes are not the normal predecessors of any other opcodes.
duke@435	350	break;
duke@435	351	case Bytecodes::_ret:
duke@435	352	// We will patch up jsr/rets in a subsequent pass.
duke@435	353	ret_list->append(current_block);
duke@435	354	break;
duke@435	355	case Bytecodes::_breakpoint:
duke@435	356	// Bail out of there are breakpoints in here.
duke@435	357	bailout = true;
duke@435	358	break;
duke@435	359	default:
duke@435	360	// Do nothing.
duke@435	361	break;
duke@435	362	}
duke@435	363	}
duke@435	364	// Patch up the jsr/ret's. We conservatively assume that any ret
duke@435	365	// can return to any jsr site.
duke@435	366	int ret_list_len = ret_list->length();
duke@435	367	int jsr_exit_list_len = jsr_exit_list->length();
duke@435	368	if (ret_list_len > 0 && jsr_exit_list_len > 0) {
duke@435	369	for (int i = jsr_exit_list_len - 1; i >= 0; i--) {
duke@435	370	BasicBlock *jsrExit = jsr_exit_list->at(i);
duke@435	371	for (int i = ret_list_len - 1; i >= 0; i--) {
duke@435	372	jsrExit->add_normal_predecessor(ret_list->at(i));
duke@435	373	}
duke@435	374	}
duke@435	375	}
duke@435	376
duke@435	377	// Compute exception edges.
duke@435	378	for (int b=_block_count-1; b >= 0; b--) {
duke@435	379	BasicBlock *block = _block_list[b];
duke@435	380	int block_start = block->start_bci();
duke@435	381	int block_limit = block->limit_bci();
duke@435	382	ciExceptionHandlerStream handlers(method());
duke@435	383	for (; !handlers.is_done(); handlers.next()) {
duke@435	384	ciExceptionHandler* handler = handlers.handler();
duke@435	385	int start = handler->start();
duke@435	386	int limit = handler->limit();
duke@435	387	int handler_bci = handler->handler_bci();
duke@435	388
duke@435	389	int intersect_start = MAX2(block_start, start);
duke@435	390	int intersect_limit = MIN2(block_limit, limit);
duke@435	391	if (intersect_start < intersect_limit) {
duke@435	392	// The catch range has a nonempty intersection with this
duke@435	393	// basic block. That means this basic block can be an
duke@435	394	// exceptional predecessor.
duke@435	395	_block_map->at(handler_bci)->add_exception_predecessor(block);
duke@435	396
duke@435	397	if (handler->is_catch_all()) {
duke@435	398	// This is a catch-all block.
duke@435	399	if (intersect_start == block_start && intersect_limit == block_limit) {
duke@435	400	// The basic block is entirely contained in this catch-all block.
duke@435	401	// Skip the rest of the exception handlers -- they can never be
duke@435	402	// reached in execution.
duke@435	403	break;
duke@435	404	}
duke@435	405	}
duke@435	406	}
duke@435	407	}
duke@435	408	}
duke@435	409	}
duke@435	410
duke@435	411	void MethodLiveness::init_gen_kill() {
duke@435	412	for (int i=_block_count-1; i >= 0; i--) {
duke@435	413	_block_list[i]->compute_gen_kill(method());
duke@435	414	}
duke@435	415	}
duke@435	416
duke@435	417	void MethodLiveness::propagate_liveness() {
duke@435	418	int num_blocks = _block_count;
duke@435	419	BasicBlock *block;
duke@435	420
duke@435	421	// We start our work list off with all blocks in it.
duke@435	422	// Alternately, we could start off the work list with the list of all
duke@435	423	// blocks which could exit the method directly, along with one block
duke@435	424	// from any infinite loop. If this matters, it can be changed. It
duke@435	425	// may not be clear from looking at the code, but the order of the
duke@435	426	// workList will be the opposite of the creation order of the basic
duke@435	427	// blocks, which should be decent for quick convergence (with the
duke@435	428	// possible exception of exception handlers, which are all created
duke@435	429	// early).
duke@435	430	_work_list = NULL;
duke@435	431	for (int i = 0; i < num_blocks; i++) {
duke@435	432	block = _block_list[i];
duke@435	433	block->set_next(_work_list);
duke@435	434	block->set_on_work_list(true);
duke@435	435	_work_list = block;
duke@435	436	}
duke@435	437
duke@435	438
duke@435	439	while ((block = work_list_get()) != NULL) {
duke@435	440	block->propagate(this);
duke@435	441	NOT_PRODUCT(_total_visits++;)
duke@435	442	}
duke@435	443	}
duke@435	444
duke@435	445	void MethodLiveness::work_list_add(BasicBlock *block) {
duke@435	446	if (!block->on_work_list()) {
duke@435	447	block->set_next(_work_list);
duke@435	448	block->set_on_work_list(true);
duke@435	449	_work_list = block;
duke@435	450	}
duke@435	451	}
duke@435	452
duke@435	453	MethodLiveness::BasicBlock *MethodLiveness::work_list_get() {
duke@435	454	BasicBlock *block = _work_list;
duke@435	455	if (block != NULL) {
duke@435	456	block->set_on_work_list(false);
duke@435	457	_work_list = block->next();
duke@435	458	}
duke@435	459	return block;
duke@435	460	}
duke@435	461
duke@435	462
duke@435	463	MethodLivenessResult MethodLiveness::get_liveness_at(int entry_bci) {
duke@435	464	int bci = entry_bci;
duke@435	465	bool is_entry = false;
duke@435	466	if (entry_bci == InvocationEntryBci) {
duke@435	467	is_entry = true;
duke@435	468	bci = 0;
duke@435	469	}
duke@435	470
ysr@777	471	MethodLivenessResult answer((uintptr_t*)NULL,0);
duke@435	472
duke@435	473	if (_block_count > 0) {
duke@435	474	if (TimeLivenessAnalysis) _time_total.start();
duke@435	475	if (TimeLivenessAnalysis) _time_query.start();
duke@435	476
duke@435	477	assert( 0 <= bci && bci < method()->code_size(), "bci out of range" );
duke@435	478	BasicBlock *block = _block_map->at(bci);
duke@435	479	// We may not be at the block start, so search backwards to find the block
duke@435	480	// containing bci.
duke@435	481	int t = bci;
duke@435	482	while (block == NULL && t > 0) {
duke@435	483	block = _block_map->at(--t);
duke@435	484	}
duke@435	485	assert( block != NULL, "invalid bytecode index; must be instruction index" );
duke@435	486	assert(bci >= block->start_bci() && bci < block->limit_bci(), "block must contain bci.");
duke@435	487
duke@435	488	answer = block->get_liveness_at(method(), bci);
duke@435	489
duke@435	490	if (is_entry && method()->is_synchronized() && !method()->is_static()) {
duke@435	491	// Synchronized methods use the receiver once on entry.
duke@435	492	answer.at_put(0, true);
duke@435	493	}
duke@435	494
duke@435	495	#ifndef PRODUCT
duke@435	496	if (TraceLivenessQuery) {
duke@435	497	tty->print("Liveness query of ");
duke@435	498	method()->print_short_name();
duke@435	499	tty->print(" @ %d : result is ", bci);
duke@435	500	answer.print_on(tty);
duke@435	501	}
duke@435	502
duke@435	503	if (TimeLivenessAnalysis) _time_query.stop();
duke@435	504	if (TimeLivenessAnalysis) _time_total.stop();
duke@435	505	#endif
duke@435	506	}
duke@435	507
duke@435	508	#ifndef PRODUCT
duke@435	509	if (TimeLivenessAnalysis) {
duke@435	510	// Collect statistics.
duke@435	511	_total_locals_queried += _bit_map_size_bits;
duke@435	512	BitCounter counter;
duke@435	513	answer.iterate(&counter);
duke@435	514	_total_live_locals_queried += counter.count();
duke@435	515	}
duke@435	516	#endif
duke@435	517
duke@435	518	return answer;
duke@435	519	}
duke@435	520
duke@435	521
duke@435	522	#ifndef PRODUCT
duke@435	523
duke@435	524	void MethodLiveness::print_times() {
duke@435	525	tty->print_cr ("Accumulated liveness analysis times/statistics:");
duke@435	526	tty->print_cr ("-----------------------------------------------");
duke@435	527	tty->print_cr (" Total : %3.3f sec.", _time_total.seconds());
duke@435	528	tty->print_cr (" Build graph : %3.3f sec. (%2.2f%%)", _time_build_graph.seconds(),
duke@435	529	_time_build_graph.seconds() * 100 / _time_total.seconds());
duke@435	530	tty->print_cr (" Gen / Kill : %3.3f sec. (%2.2f%%)", _time_gen_kill.seconds(),
duke@435	531	_time_gen_kill.seconds() * 100 / _time_total.seconds());
duke@435	532	tty->print_cr (" Dataflow : %3.3f sec. (%2.2f%%)", _time_flow.seconds(),
duke@435	533	_time_flow.seconds() * 100 / _time_total.seconds());
duke@435	534	tty->print_cr (" Query : %3.3f sec. (%2.2f%%)", _time_query.seconds(),
duke@435	535	_time_query.seconds() * 100 / _time_total.seconds());
duke@435	536	tty->print_cr (" #bytes : %8d (%3.0f bytes per sec)",
duke@435	537	_total_bytes,
duke@435	538	_total_bytes / _time_total.seconds());
duke@435	539	tty->print_cr (" #methods : %8d (%3.0f methods per sec)",
duke@435	540	_total_methods,
duke@435	541	_total_methods / _time_total.seconds());
duke@435	542	tty->print_cr (" avg locals : %3.3f max locals : %3d",
duke@435	543	(float)_total_method_locals / _total_methods,
duke@435	544	_max_method_locals);
duke@435	545	tty->print_cr (" avg blocks : %3.3f max blocks : %3d",
duke@435	546	(float)_total_blocks / _total_methods,
duke@435	547	_max_method_blocks);
duke@435	548	tty->print_cr (" avg bytes : %3.3f",
duke@435	549	(float)_total_bytes / _total_methods);
duke@435	550	tty->print_cr (" #blocks : %8d",
duke@435	551	_total_blocks);
duke@435	552	tty->print_cr (" avg normal predecessors : %3.3f max normal predecessors : %3d",
duke@435	553	(float)_total_edges / _total_blocks,
duke@435	554	_max_block_edges);
duke@435	555	tty->print_cr (" avg exception predecessors : %3.3f max exception predecessors : %3d",
duke@435	556	(float)_total_exc_edges / _total_blocks,
duke@435	557	_max_block_exc_edges);
duke@435	558	tty->print_cr (" avg visits : %3.3f",
duke@435	559	(float)_total_visits / _total_blocks);
duke@435	560	tty->print_cr (" #locals queried : %8d #live : %8d %%live : %2.2f%%",
duke@435	561	_total_locals_queried,
duke@435	562	_total_live_locals_queried,
duke@435	563	100.0 * _total_live_locals_queried / _total_locals_queried);
duke@435	564	}
duke@435	565
duke@435	566	#endif
duke@435	567
duke@435	568
duke@435	569	MethodLiveness::BasicBlock::BasicBlock(MethodLiveness *analyzer, int start, int limit) :
duke@435	570	_gen((uintptr_t*)analyzer->arena()->Amalloc(BytesPerWord * analyzer->bit_map_size_words()),
duke@435	571	analyzer->bit_map_size_bits()),
duke@435	572	_kill((uintptr_t*)analyzer->arena()->Amalloc(BytesPerWord * analyzer->bit_map_size_words()),
duke@435	573	analyzer->bit_map_size_bits()),
duke@435	574	_entry((uintptr_t*)analyzer->arena()->Amalloc(BytesPerWord * analyzer->bit_map_size_words()),
duke@435	575	analyzer->bit_map_size_bits()),
duke@435	576	_normal_exit((uintptr_t*)analyzer->arena()->Amalloc(BytesPerWord * analyzer->bit_map_size_words()),
duke@435	577	analyzer->bit_map_size_bits()),
duke@435	578	_exception_exit((uintptr_t*)analyzer->arena()->Amalloc(BytesPerWord * analyzer->bit_map_size_words()),
duke@435	579	analyzer->bit_map_size_bits()),
duke@435	580	_last_bci(-1) {
duke@435	581	_analyzer = analyzer;
duke@435	582	_start_bci = start;
duke@435	583	_limit_bci = limit;
duke@435	584	_normal_predecessors =
duke@435	585	new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
duke@435	586	_exception_predecessors =
duke@435	587	new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
duke@435	588	_normal_exit.clear();
duke@435	589	_exception_exit.clear();
duke@435	590	_entry.clear();
duke@435	591
duke@435	592	// this initialization is not strictly necessary.
duke@435	593	// _gen and _kill are cleared at the beginning of compute_gen_kill_range()
duke@435	594	_gen.clear();
duke@435	595	_kill.clear();
duke@435	596	}
duke@435	597
duke@435	598
duke@435	599
duke@435	600	MethodLiveness::BasicBlock *MethodLiveness::BasicBlock::split(int split_bci) {
duke@435	601	int start = _start_bci;
duke@435	602	int limit = _limit_bci;
duke@435	603
duke@435	604	if (TraceLivenessGen) {
duke@435	605	tty->print_cr(" ** Splitting block (%d,%d) at %d", start, limit, split_bci);
duke@435	606	}
duke@435	607
duke@435	608	GrowableArray<BasicBlock*>* save_predecessors = _normal_predecessors;
duke@435	609
duke@435	610	assert (start < split_bci && split_bci < limit, "improper split");
duke@435	611
duke@435	612	// Make a new block to cover the first half of the range.
duke@435	613	BasicBlock *first_half = new (_analyzer->arena()) BasicBlock(_analyzer, start, split_bci);
duke@435	614
duke@435	615	// Assign correct values to the second half (this)
duke@435	616	_normal_predecessors = first_half->_normal_predecessors;
duke@435	617	_start_bci = split_bci;
duke@435	618	add_normal_predecessor(first_half);
duke@435	619
duke@435	620	// Assign correct predecessors to the new first half
duke@435	621	first_half->_normal_predecessors = save_predecessors;
duke@435	622
duke@435	623	return first_half;
duke@435	624	}
duke@435	625
duke@435	626	void MethodLiveness::BasicBlock::compute_gen_kill(ciMethod* method) {
duke@435	627	ciBytecodeStream bytes(method);
duke@435	628	bytes.reset_to_bci(start_bci());
duke@435	629	bytes.set_max_bci(limit_bci());
duke@435	630	compute_gen_kill_range(&bytes);
duke@435	631
duke@435	632	}
duke@435	633
duke@435	634	void MethodLiveness::BasicBlock::compute_gen_kill_range(ciBytecodeStream *bytes) {
duke@435	635	_gen.clear();
duke@435	636	_kill.clear();
duke@435	637
duke@435	638	while (bytes->next() != ciBytecodeStream::EOBC()) {
duke@435	639	compute_gen_kill_single(bytes);
duke@435	640	}
duke@435	641	}
duke@435	642
duke@435	643	void MethodLiveness::BasicBlock::compute_gen_kill_single(ciBytecodeStream *instruction) {
duke@435	644	int localNum;
duke@435	645
duke@435	646	// We prohibit _gen and _kill from having locals in common. If we
duke@435	647	// know that one is definitely going to be applied before the other,
duke@435	648	// we could save some computation time by relaxing this prohibition.
duke@435	649
duke@435	650	switch (instruction->cur_bc()) {
duke@435	651	case Bytecodes::_nop:
duke@435	652	case Bytecodes::_goto:
duke@435	653	case Bytecodes::_goto_w:
duke@435	654	case Bytecodes::_aconst_null:
duke@435	655	case Bytecodes::_new:
duke@435	656	case Bytecodes::_iconst_m1:
duke@435	657	case Bytecodes::_iconst_0:
duke@435	658	case Bytecodes::_iconst_1:
duke@435	659	case Bytecodes::_iconst_2:
duke@435	660	case Bytecodes::_iconst_3:
duke@435	661	case Bytecodes::_iconst_4:
duke@435	662	case Bytecodes::_iconst_5:
duke@435	663	case Bytecodes::_fconst_0:
duke@435	664	case Bytecodes::_fconst_1:
duke@435	665	case Bytecodes::_fconst_2:
duke@435	666	case Bytecodes::_bipush:
duke@435	667	case Bytecodes::_sipush:
duke@435	668	case Bytecodes::_lconst_0:
duke@435	669	case Bytecodes::_lconst_1:
duke@435	670	case Bytecodes::_dconst_0:
duke@435	671	case Bytecodes::_dconst_1:
duke@435	672	case Bytecodes::_ldc2_w:
duke@435	673	case Bytecodes::_ldc:
duke@435	674	case Bytecodes::_ldc_w:
duke@435	675	case Bytecodes::_iaload:
duke@435	676	case Bytecodes::_faload:
duke@435	677	case Bytecodes::_baload:
duke@435	678	case Bytecodes::_caload:
duke@435	679	case Bytecodes::_saload:
duke@435	680	case Bytecodes::_laload:
duke@435	681	case Bytecodes::_daload:
duke@435	682	case Bytecodes::_aaload:
duke@435	683	case Bytecodes::_iastore:
duke@435	684	case Bytecodes::_fastore:
duke@435	685	case Bytecodes::_bastore:
duke@435	686	case Bytecodes::_castore:
duke@435	687	case Bytecodes::_sastore:
duke@435	688	case Bytecodes::_lastore:
duke@435	689	case Bytecodes::_dastore:
duke@435	690	case Bytecodes::_aastore:
duke@435	691	case Bytecodes::_pop:
duke@435	692	case Bytecodes::_pop2:
duke@435	693	case Bytecodes::_dup:
duke@435	694	case Bytecodes::_dup_x1:
duke@435	695	case Bytecodes::_dup_x2:
duke@435	696	case Bytecodes::_dup2:
duke@435	697	case Bytecodes::_dup2_x1:
duke@435	698	case Bytecodes::_dup2_x2:
duke@435	699	case Bytecodes::_swap:
duke@435	700	case Bytecodes::_iadd:
duke@435	701	case Bytecodes::_fadd:
duke@435	702	case Bytecodes::_isub:
duke@435	703	case Bytecodes::_fsub:
duke@435	704	case Bytecodes::_imul:
duke@435	705	case Bytecodes::_fmul:
duke@435	706	case Bytecodes::_idiv:
duke@435	707	case Bytecodes::_fdiv:
duke@435	708	case Bytecodes::_irem:
duke@435	709	case Bytecodes::_frem:
duke@435	710	case Bytecodes::_ishl:
duke@435	711	case Bytecodes::_ishr:
duke@435	712	case Bytecodes::_iushr:
duke@435	713	case Bytecodes::_iand:
duke@435	714	case Bytecodes::_ior:
duke@435	715	case Bytecodes::_ixor:
duke@435	716	case Bytecodes::_l2f:
duke@435	717	case Bytecodes::_l2i:
duke@435	718	case Bytecodes::_d2f:
duke@435	719	case Bytecodes::_d2i:
duke@435	720	case Bytecodes::_fcmpl:
duke@435	721	case Bytecodes::_fcmpg:
duke@435	722	case Bytecodes::_ladd:
duke@435	723	case Bytecodes::_dadd:
duke@435	724	case Bytecodes::_lsub:
duke@435	725	case Bytecodes::_dsub:
duke@435	726	case Bytecodes::_lmul:
duke@435	727	case Bytecodes::_dmul:
duke@435	728	case Bytecodes::_ldiv:
duke@435	729	case Bytecodes::_ddiv:
duke@435	730	case Bytecodes::_lrem:
duke@435	731	case Bytecodes::_drem:
duke@435	732	case Bytecodes::_land:
duke@435	733	case Bytecodes::_lor:
duke@435	734	case Bytecodes::_lxor:
duke@435	735	case Bytecodes::_ineg:
duke@435	736	case Bytecodes::_fneg:
duke@435	737	case Bytecodes::_i2f:
duke@435	738	case Bytecodes::_f2i:
duke@435	739	case Bytecodes::_i2c:
duke@435	740	case Bytecodes::_i2s:
duke@435	741	case Bytecodes::_i2b:
duke@435	742	case Bytecodes::_lneg:
duke@435	743	case Bytecodes::_dneg:
duke@435	744	case Bytecodes::_l2d:
duke@435	745	case Bytecodes::_d2l:
duke@435	746	case Bytecodes::_lshl:
duke@435	747	case Bytecodes::_lshr:
duke@435	748	case Bytecodes::_lushr:
duke@435	749	case Bytecodes::_i2l:
duke@435	750	case Bytecodes::_i2d:
duke@435	751	case Bytecodes::_f2l:
duke@435	752	case Bytecodes::_f2d:
duke@435	753	case Bytecodes::_lcmp:
duke@435	754	case Bytecodes::_dcmpl:
duke@435	755	case Bytecodes::_dcmpg:
duke@435	756	case Bytecodes::_ifeq:
duke@435	757	case Bytecodes::_ifne:
duke@435	758	case Bytecodes::_iflt:
duke@435	759	case Bytecodes::_ifge:
duke@435	760	case Bytecodes::_ifgt:
duke@435	761	case Bytecodes::_ifle:
duke@435	762	case Bytecodes::_tableswitch:
duke@435	763	case Bytecodes::_ireturn:
duke@435	764	case Bytecodes::_freturn:
duke@435	765	case Bytecodes::_if_icmpeq:
duke@435	766	case Bytecodes::_if_icmpne:
duke@435	767	case Bytecodes::_if_icmplt:
duke@435	768	case Bytecodes::_if_icmpge:
duke@435	769	case Bytecodes::_if_icmpgt:
duke@435	770	case Bytecodes::_if_icmple:
duke@435	771	case Bytecodes::_lreturn:
duke@435	772	case Bytecodes::_dreturn:
duke@435	773	case Bytecodes::_if_acmpeq:
duke@435	774	case Bytecodes::_if_acmpne:
duke@435	775	case Bytecodes::_jsr:
duke@435	776	case Bytecodes::_jsr_w:
duke@435	777	case Bytecodes::_getstatic:
duke@435	778	case Bytecodes::_putstatic:
duke@435	779	case Bytecodes::_getfield:
duke@435	780	case Bytecodes::_putfield:
duke@435	781	case Bytecodes::_invokevirtual:
duke@435	782	case Bytecodes::_invokespecial:
duke@435	783	case Bytecodes::_invokestatic:
duke@435	784	case Bytecodes::_invokeinterface:
twisti@1570	785	case Bytecodes::_invokedynamic:
duke@435	786	case Bytecodes::_newarray:
duke@435	787	case Bytecodes::_anewarray:
duke@435	788	case Bytecodes::_checkcast:
duke@435	789	case Bytecodes::_arraylength:
duke@435	790	case Bytecodes::_instanceof:
duke@435	791	case Bytecodes::_athrow:
duke@435	792	case Bytecodes::_areturn:
duke@435	793	case Bytecodes::_monitorenter:
duke@435	794	case Bytecodes::_monitorexit:
duke@435	795	case Bytecodes::_ifnull:
duke@435	796	case Bytecodes::_ifnonnull:
duke@435	797	case Bytecodes::_multianewarray:
duke@435	798	case Bytecodes::_lookupswitch:
duke@435	799	// These bytecodes have no effect on the method's locals.
duke@435	800	break;
duke@435	801
duke@435	802	case Bytecodes::_return:
duke@435	803	if (instruction->method()->intrinsic_id() == vmIntrinsics::_Object_init) {
duke@435	804	// return from Object.init implicitly registers a finalizer
duke@435	805	// for the receiver if needed, so keep it alive.
duke@435	806	load_one(0);
duke@435	807	}
duke@435	808	break;
duke@435	809
duke@435	810
duke@435	811	case Bytecodes::_lload:
duke@435	812	case Bytecodes::_dload:
duke@435	813	load_two(instruction->get_index());
duke@435	814	break;
duke@435	815
duke@435	816	case Bytecodes::_lload_0:
duke@435	817	case Bytecodes::_dload_0:
duke@435	818	load_two(0);
duke@435	819	break;
duke@435	820
duke@435	821	case Bytecodes::_lload_1:
duke@435	822	case Bytecodes::_dload_1:
duke@435	823	load_two(1);
duke@435	824	break;
duke@435	825
duke@435	826	case Bytecodes::_lload_2:
duke@435	827	case Bytecodes::_dload_2:
duke@435	828	load_two(2);
duke@435	829	break;
duke@435	830
duke@435	831	case Bytecodes::_lload_3:
duke@435	832	case Bytecodes::_dload_3:
duke@435	833	load_two(3);
duke@435	834	break;
duke@435	835
duke@435	836	case Bytecodes::_iload:
duke@435	837	case Bytecodes::_iinc:
duke@435	838	case Bytecodes::_fload:
duke@435	839	case Bytecodes::_aload:
duke@435	840	case Bytecodes::_ret:
duke@435	841	load_one(instruction->get_index());
duke@435	842	break;
duke@435	843
duke@435	844	case Bytecodes::_iload_0:
duke@435	845	case Bytecodes::_fload_0:
duke@435	846	case Bytecodes::_aload_0:
duke@435	847	load_one(0);
duke@435	848	break;
duke@435	849
duke@435	850	case Bytecodes::_iload_1:
duke@435	851	case Bytecodes::_fload_1:
duke@435	852	case Bytecodes::_aload_1:
duke@435	853	load_one(1);
duke@435	854	break;
duke@435	855
duke@435	856	case Bytecodes::_iload_2:
duke@435	857	case Bytecodes::_fload_2:
duke@435	858	case Bytecodes::_aload_2:
duke@435	859	load_one(2);
duke@435	860	break;
duke@435	861
duke@435	862	case Bytecodes::_iload_3:
duke@435	863	case Bytecodes::_fload_3:
duke@435	864	case Bytecodes::_aload_3:
duke@435	865	load_one(3);
duke@435	866	break;
duke@435	867
duke@435	868	case Bytecodes::_lstore:
duke@435	869	case Bytecodes::_dstore:
duke@435	870	store_two(localNum = instruction->get_index());
duke@435	871	break;
duke@435	872
duke@435	873	case Bytecodes::_lstore_0:
duke@435	874	case Bytecodes::_dstore_0:
duke@435	875	store_two(0);
duke@435	876	break;
duke@435	877
duke@435	878	case Bytecodes::_lstore_1:
duke@435	879	case Bytecodes::_dstore_1:
duke@435	880	store_two(1);
duke@435	881	break;
duke@435	882
duke@435	883	case Bytecodes::_lstore_2:
duke@435	884	case Bytecodes::_dstore_2:
duke@435	885	store_two(2);
duke@435	886	break;
duke@435	887
duke@435	888	case Bytecodes::_lstore_3:
duke@435	889	case Bytecodes::_dstore_3:
duke@435	890	store_two(3);
duke@435	891	break;
duke@435	892
duke@435	893	case Bytecodes::_istore:
duke@435	894	case Bytecodes::_fstore:
duke@435	895	case Bytecodes::_astore:
duke@435	896	store_one(instruction->get_index());
duke@435	897	break;
duke@435	898
duke@435	899	case Bytecodes::_istore_0:
duke@435	900	case Bytecodes::_fstore_0:
duke@435	901	case Bytecodes::_astore_0:
duke@435	902	store_one(0);
duke@435	903	break;
duke@435	904
duke@435	905	case Bytecodes::_istore_1:
duke@435	906	case Bytecodes::_fstore_1:
duke@435	907	case Bytecodes::_astore_1:
duke@435	908	store_one(1);
duke@435	909	break;
duke@435	910
duke@435	911	case Bytecodes::_istore_2:
duke@435	912	case Bytecodes::_fstore_2:
duke@435	913	case Bytecodes::_astore_2:
duke@435	914	store_one(2);
duke@435	915	break;
duke@435	916
duke@435	917	case Bytecodes::_istore_3:
duke@435	918	case Bytecodes::_fstore_3:
duke@435	919	case Bytecodes::_astore_3:
duke@435	920	store_one(3);
duke@435	921	break;
duke@435	922
duke@435	923	case Bytecodes::_wide:
duke@435	924	fatal("Iterator should skip this bytecode");
duke@435	925	break;
duke@435	926
duke@435	927	default:
duke@435	928	tty->print("unexpected opcode: %d\n", instruction->cur_bc());
duke@435	929	ShouldNotReachHere();
duke@435	930	break;
duke@435	931	}
duke@435	932	}
duke@435	933
duke@435	934	void MethodLiveness::BasicBlock::load_two(int local) {
duke@435	935	load_one(local);
duke@435	936	load_one(local+1);
duke@435	937	}
duke@435	938
duke@435	939	void MethodLiveness::BasicBlock::load_one(int local) {
duke@435	940	if (!_kill.at(local)) {
duke@435	941	_gen.at_put(local, true);
duke@435	942	}
duke@435	943	}
duke@435	944
duke@435	945	void MethodLiveness::BasicBlock::store_two(int local) {
duke@435	946	store_one(local);
duke@435	947	store_one(local+1);
duke@435	948	}
duke@435	949
duke@435	950	void MethodLiveness::BasicBlock::store_one(int local) {
duke@435	951	if (!_gen.at(local)) {
duke@435	952	_kill.at_put(local, true);
duke@435	953	}
duke@435	954	}
duke@435	955
duke@435	956	void MethodLiveness::BasicBlock::propagate(MethodLiveness *ml) {
duke@435	957	// These set operations could be combined for efficiency if the
duke@435	958	// performance of this analysis becomes an issue.
duke@435	959	_entry.set_union(_normal_exit);
duke@435	960	_entry.set_difference(_kill);
duke@435	961	_entry.set_union(_gen);
duke@435	962
duke@435	963	// Note that we merge information from our exceptional successors
duke@435	964	// just once, rather than at individual bytecodes.
duke@435	965	_entry.set_union(_exception_exit);
duke@435	966
duke@435	967	if (TraceLivenessGen) {
duke@435	968	tty->print_cr(" ** Visiting block at %d **", start_bci());
duke@435	969	print_on(tty);
duke@435	970	}
duke@435	971
duke@435	972	int i;
duke@435	973	for (i=_normal_predecessors->length()-1; i>=0; i--) {
duke@435	974	BasicBlock *block = _normal_predecessors->at(i);
duke@435	975	if (block->merge_normal(_entry)) {
duke@435	976	ml->work_list_add(block);
duke@435	977	}
duke@435	978	}
duke@435	979	for (i=_exception_predecessors->length()-1; i>=0; i--) {
duke@435	980	BasicBlock *block = _exception_predecessors->at(i);
duke@435	981	if (block->merge_exception(_entry)) {
duke@435	982	ml->work_list_add(block);
duke@435	983	}
duke@435	984	}
duke@435	985	}
duke@435	986
duke@435	987	bool MethodLiveness::BasicBlock::merge_normal(BitMap other) {
duke@435	988	return _normal_exit.set_union_with_result(other);
duke@435	989	}
duke@435	990
duke@435	991	bool MethodLiveness::BasicBlock::merge_exception(BitMap other) {
duke@435	992	return _exception_exit.set_union_with_result(other);
duke@435	993	}
duke@435	994
duke@435	995	MethodLivenessResult MethodLiveness::BasicBlock::get_liveness_at(ciMethod* method, int bci) {
duke@435	996	MethodLivenessResult answer(NEW_RESOURCE_ARRAY(uintptr_t, _analyzer->bit_map_size_words()),
duke@435	997	_analyzer->bit_map_size_bits());
duke@435	998	answer.set_is_valid();
duke@435	999
duke@435	1000	#ifndef ASSERT
duke@435	1001	if (bci == start_bci()) {
duke@435	1002	answer.set_from(_entry);
duke@435	1003	return answer;
duke@435	1004	}
duke@435	1005	#endif
duke@435	1006
duke@435	1007	#ifdef ASSERT
duke@435	1008	ResourceMark rm;
duke@435	1009	BitMap g(_gen.size()); g.set_from(_gen);
duke@435	1010	BitMap k(_kill.size()); k.set_from(_kill);
duke@435	1011	#endif
duke@435	1012	if (_last_bci != bci || trueInDebug) {
duke@435	1013	ciBytecodeStream bytes(method);
duke@435	1014	bytes.reset_to_bci(bci);
duke@435	1015	bytes.set_max_bci(limit_bci());
duke@435	1016	compute_gen_kill_range(&bytes);
duke@435	1017	assert(_last_bci != bci ||
duke@435	1018	(g.is_same(_gen) && k.is_same(_kill)), "cached computation is incorrect");
duke@435	1019	_last_bci = bci;
duke@435	1020	}
duke@435	1021
duke@435	1022	answer.clear();
duke@435	1023	answer.set_union(_normal_exit);
duke@435	1024	answer.set_difference(_kill);
duke@435	1025	answer.set_union(_gen);
duke@435	1026	answer.set_union(_exception_exit);
duke@435	1027
duke@435	1028	#ifdef ASSERT
duke@435	1029	if (bci == start_bci()) {
duke@435	1030	assert(answer.is_same(_entry), "optimized answer must be accurate");
duke@435	1031	}
duke@435	1032	#endif
duke@435	1033
duke@435	1034	return answer;
duke@435	1035	}
duke@435	1036
duke@435	1037	#ifndef PRODUCT
duke@435	1038
duke@435	1039	void MethodLiveness::BasicBlock::print_on(outputStream *os) const {
duke@435	1040	os->print_cr("===================================================================");
duke@435	1041	os->print_cr(" Block start: %4d, limit: %4d", _start_bci, _limit_bci);
duke@435	1042	os->print (" Normal predecessors (%2d) @", _normal_predecessors->length());
duke@435	1043	int i;
duke@435	1044	for (i=0; i < _normal_predecessors->length(); i++) {
duke@435	1045	os->print(" %4d", _normal_predecessors->at(i)->start_bci());
duke@435	1046	}
duke@435	1047	os->cr();
duke@435	1048	os->print (" Exceptional predecessors (%2d) @", _exception_predecessors->length());
duke@435	1049	for (i=0; i < _exception_predecessors->length(); i++) {
duke@435	1050	os->print(" %4d", _exception_predecessors->at(i)->start_bci());
duke@435	1051	}
duke@435	1052	os->cr();
duke@435	1053	os->print (" Normal Exit : ");
duke@435	1054	_normal_exit.print_on(os);
duke@435	1055	os->print (" Gen : ");
duke@435	1056	_gen.print_on(os);
duke@435	1057	os->print (" Kill : ");
duke@435	1058	_kill.print_on(os);
duke@435	1059	os->print (" Exception Exit: ");
duke@435	1060	_exception_exit.print_on(os);
duke@435	1061	os->print (" Entry : ");
duke@435	1062	_entry.print_on(os);
duke@435	1063	}
duke@435	1064
duke@435	1065	#endif // PRODUCT