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src/share/vm/c1/c1_ValueMap.cpp@dc7f315e41f7 (annotated)

src/share/vm/c1/c1_ValueMap.cpp

Wed, 27 Aug 2008 00:21:55 -0700

author

never

date

Wed, 27 Aug 2008 00:21:55 -0700

changeset 739

dc7f315e41f7

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

5108146: Merge i486 and amd64 cpu directories
6459804: Want client (c1) compiler for x86_64 (amd64) for faster start-up
Reviewed-by: kvn

duke@435	1	/*
duke@435	2	* Copyright 1999-2005 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	#include "incls/_precompiled.incl"
duke@435	26	#include "incls/_c1_ValueMap.cpp.incl"
duke@435	27
duke@435	28
duke@435	29	#ifndef PRODUCT
duke@435	30
duke@435	31	int ValueMap::_number_of_finds = 0;
duke@435	32	int ValueMap::_number_of_hits = 0;
duke@435	33	int ValueMap::_number_of_kills = 0;
duke@435	34
duke@435	35	#define TRACE_VALUE_NUMBERING(code) if (PrintValueNumbering) { code; }
duke@435	36
duke@435	37	#else
duke@435	38
duke@435	39	#define TRACE_VALUE_NUMBERING(code)
duke@435	40
duke@435	41	#endif
duke@435	42
duke@435	43
duke@435	44	ValueMap::ValueMap()
duke@435	45	: _nesting(0)
duke@435	46	, _entries(ValueMapInitialSize, NULL)
duke@435	47	, _killed_values()
duke@435	48	, _entry_count(0)
duke@435	49	{
duke@435	50	NOT_PRODUCT(reset_statistics());
duke@435	51	}
duke@435	52
duke@435	53
duke@435	54	ValueMap::ValueMap(ValueMap* old)
duke@435	55	: _nesting(old->_nesting + 1)
duke@435	56	, _entries(old->_entries.length())
duke@435	57	, _killed_values()
duke@435	58	, _entry_count(old->_entry_count)
duke@435	59	{
duke@435	60	for (int i = size() - 1; i >= 0; i--) {
duke@435	61	_entries.at_put(i, old->entry_at(i));
duke@435	62	}
duke@435	63	_killed_values.set_from(&old->_killed_values);
duke@435	64	}
duke@435	65
duke@435	66
duke@435	67	void ValueMap::increase_table_size() {
duke@435	68	int old_size = size();
duke@435	69	int new_size = old_size * 2 + 1;
duke@435	70
duke@435	71	ValueMapEntryList worklist(8);
duke@435	72	ValueMapEntryArray new_entries(new_size, NULL);
duke@435	73	int new_entry_count = 0;
duke@435	74
duke@435	75	TRACE_VALUE_NUMBERING(tty->print_cr("increasing table size from %d to %d", old_size, new_size));
duke@435	76
duke@435	77	for (int i = old_size - 1; i >= 0; i--) {
duke@435	78	ValueMapEntry* entry;
duke@435	79	for (entry = entry_at(i); entry != NULL; entry = entry->next()) {
duke@435	80	if (!is_killed(entry->value())) {
duke@435	81	worklist.push(entry);
duke@435	82	}
duke@435	83	}
duke@435	84
duke@435	85	while (!worklist.is_empty()) {
duke@435	86	entry = worklist.pop();
duke@435	87	int new_index = entry_index(entry->hash(), new_size);
duke@435	88
duke@435	89	if (entry->nesting() != nesting() && new_entries.at(new_index) != entry->next()) {
duke@435	90	// changing entries with a lower nesting than the current nesting of the table
duke@435	91	// is not allowed because then the same entry is contained in multiple value maps.
duke@435	92	// clone entry when next-pointer must be changed
duke@435	93	entry = new ValueMapEntry(entry->hash(), entry->value(), entry->nesting(), NULL);
duke@435	94	}
duke@435	95	entry->set_next(new_entries.at(new_index));
duke@435	96	new_entries.at_put(new_index, entry);
duke@435	97	new_entry_count++;
duke@435	98	}
duke@435	99	}
duke@435	100
duke@435	101	_entries = new_entries;
duke@435	102	_entry_count = new_entry_count;
duke@435	103	}
duke@435	104
duke@435	105
duke@435	106	Value ValueMap::find_insert(Value x) {
duke@435	107	const intx hash = x->hash();
duke@435	108	if (hash != 0) {
duke@435	109	// 0 hash means: exclude from value numbering
duke@435	110	NOT_PRODUCT(_number_of_finds++);
duke@435	111
duke@435	112	for (ValueMapEntry* entry = entry_at(entry_index(hash, size())); entry != NULL; entry = entry->next()) {
duke@435	113	if (entry->hash() == hash) {
duke@435	114	Value f = entry->value();
duke@435	115
duke@435	116	if (!is_killed(f) && f->is_equal(x)) {
duke@435	117	NOT_PRODUCT(_number_of_hits++);
duke@435	118	TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: %s %c%d equal to %c%d (size %d, entries %d, nesting-diff %d)", x->name(), x->type()->tchar(), x->id(), f->type()->tchar(), f->id(), size(), entry_count(), nesting() - entry->nesting()));
duke@435	119
duke@435	120	if (entry->nesting() != nesting() && f->as_Constant() == NULL) {
duke@435	121	// non-constant values of of another block must be pinned,
duke@435	122	// otherwise it is possible that they are not evaluated
duke@435	123	f->pin(Instruction::PinGlobalValueNumbering);
duke@435	124	}
duke@435	125
duke@435	126	return f;
duke@435	127
duke@435	128	}
duke@435	129	}
duke@435	130	}
duke@435	131
duke@435	132	// x not found, so insert it
duke@435	133	if (entry_count() >= size_threshold()) {
duke@435	134	increase_table_size();
duke@435	135	}
duke@435	136	int idx = entry_index(hash, size());
duke@435	137	_entries.at_put(idx, new ValueMapEntry(hash, x, nesting(), entry_at(idx)));
duke@435	138	_entry_count++;
duke@435	139
duke@435	140	TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: insert %s %c%d (size %d, entries %d, nesting %d)", x->name(), x->type()->tchar(), x->id(), size(), entry_count(), nesting()));
duke@435	141	}
duke@435	142
duke@435	143	return x;
duke@435	144	}
duke@435	145
duke@435	146
duke@435	147	#define GENERIC_KILL_VALUE(must_kill_implementation) \
duke@435	148	NOT_PRODUCT(_number_of_kills++); \
duke@435	149	\
duke@435	150	for (int i = size() - 1; i >= 0; i--) { \
duke@435	151	ValueMapEntry* prev_entry = NULL; \
duke@435	152	for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { \
duke@435	153	Value value = entry->value(); \
duke@435	154	\
duke@435	155	must_kill_implementation(must_kill, entry, value) \
duke@435	156	\
duke@435	157	if (must_kill) { \
duke@435	158	kill_value(value); \
duke@435	159	\
duke@435	160	if (prev_entry == NULL) { \
duke@435	161	_entries.at_put(i, entry->next()); \
duke@435	162	_entry_count--; \
duke@435	163	} else if (prev_entry->nesting() == nesting()) { \
duke@435	164	prev_entry->set_next(entry->next()); \
duke@435	165	_entry_count--; \
duke@435	166	} else { \
duke@435	167	prev_entry = entry; \
duke@435	168	} \
duke@435	169	\
duke@435	170	TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: killed %s %c%d (size %d, entries %d, nesting-diff %d)", value->name(), value->type()->tchar(), value->id(), size(), entry_count(), nesting() - entry->nesting())); \
duke@435	171	} else { \
duke@435	172	prev_entry = entry; \
duke@435	173	} \
duke@435	174	} \
duke@435	175	} \
duke@435	176
duke@435	177	#define MUST_KILL_MEMORY(must_kill, entry, value) \
duke@435	178	bool must_kill = value->as_LoadField() != NULL || value->as_LoadIndexed() != NULL;
duke@435	179
duke@435	180	#define MUST_KILL_ARRAY(must_kill, entry, value) \
duke@435	181	bool must_kill = value->as_LoadIndexed() != NULL \
duke@435	182	&& value->type()->tag() == type->tag();
duke@435	183
duke@435	184	#define MUST_KILL_FIELD(must_kill, entry, value) \
duke@435	185	/* ciField's are not unique; must compare their contents */ \
duke@435	186	LoadField* lf = value->as_LoadField(); \
duke@435	187	bool must_kill = lf != NULL \
duke@435	188	&& lf->field()->holder() == field->holder() \
duke@435	189	&& lf->field()->offset() == field->offset();
duke@435	190
duke@435	191	#define MUST_KILL_EXCEPTION(must_kill, entry, value) \
duke@435	192	assert(entry->nesting() < nesting(), "must not find bigger nesting than current"); \
duke@435	193	bool must_kill = (entry->nesting() == nesting() - 1);
duke@435	194
duke@435	195
duke@435	196	void ValueMap::kill_memory() {
duke@435	197	GENERIC_KILL_VALUE(MUST_KILL_MEMORY);
duke@435	198	}
duke@435	199
duke@435	200	void ValueMap::kill_array(ValueType* type) {
duke@435	201	GENERIC_KILL_VALUE(MUST_KILL_ARRAY);
duke@435	202	}
duke@435	203
duke@435	204	void ValueMap::kill_field(ciField* field) {
duke@435	205	GENERIC_KILL_VALUE(MUST_KILL_FIELD);
duke@435	206	}
duke@435	207
duke@435	208	void ValueMap::kill_exception() {
duke@435	209	GENERIC_KILL_VALUE(MUST_KILL_EXCEPTION);
duke@435	210	}
duke@435	211
duke@435	212
duke@435	213	void ValueMap::kill_map(ValueMap* map) {
duke@435	214	assert(is_global_value_numbering(), "only for global value numbering");
duke@435	215	_killed_values.set_union(&map->_killed_values);
duke@435	216	}
duke@435	217
duke@435	218	void ValueMap::kill_all() {
duke@435	219	assert(is_local_value_numbering(), "only for local value numbering");
duke@435	220	for (int i = size() - 1; i >= 0; i--) {
duke@435	221	_entries.at_put(i, NULL);
duke@435	222	}
duke@435	223	_entry_count = 0;
duke@435	224	}
duke@435	225
duke@435	226
duke@435	227	#ifndef PRODUCT
duke@435	228
duke@435	229	void ValueMap::print() {
duke@435	230	tty->print_cr("(size %d, entries %d, nesting %d)", size(), entry_count(), nesting());
duke@435	231
duke@435	232	int entries = 0;
duke@435	233	for (int i = 0; i < size(); i++) {
duke@435	234	if (entry_at(i) != NULL) {
duke@435	235	tty->print(" %2d: ", i);
duke@435	236	for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) {
duke@435	237	Value value = entry->value();
duke@435	238	tty->print("%s %c%d (%s%d) -> ", value->name(), value->type()->tchar(), value->id(), is_killed(value) ? "x" : "", entry->nesting());
duke@435	239	entries++;
duke@435	240	}
duke@435	241	tty->print_cr("NULL");
duke@435	242	}
duke@435	243	}
duke@435	244
duke@435	245	_killed_values.print();
duke@435	246	assert(entry_count() == entries, "entry_count incorrect");
duke@435	247	}
duke@435	248
duke@435	249	void ValueMap::reset_statistics() {
duke@435	250	_number_of_finds = 0;
duke@435	251	_number_of_hits = 0;
duke@435	252	_number_of_kills = 0;
duke@435	253	}
duke@435	254
duke@435	255	void ValueMap::print_statistics() {
duke@435	256	float hit_rate = 0;
duke@435	257	if (_number_of_finds != 0) {
duke@435	258	hit_rate = (float)_number_of_hits / _number_of_finds;
duke@435	259	}
duke@435	260
duke@435	261	tty->print_cr("finds:%3d hits:%3d kills:%3d hit rate: %1.4f", _number_of_finds, _number_of_hits, _number_of_kills, hit_rate);
duke@435	262	}
duke@435	263
duke@435	264	#endif
duke@435	265
duke@435	266
duke@435	267
duke@435	268	class ShortLoopOptimizer : public ValueNumberingVisitor {
duke@435	269	private:
duke@435	270	GlobalValueNumbering* _gvn;
duke@435	271	BlockList _loop_blocks;
duke@435	272	bool _too_complicated_loop;
duke@435	273
duke@435	274	// simplified access to methods of GlobalValueNumbering
duke@435	275	ValueMap* current_map() { return _gvn->current_map(); }
duke@435	276	ValueMap* value_map_of(BlockBegin* block) { return _gvn->value_map_of(block); }
duke@435	277
duke@435	278	// implementation for abstract methods of ValueNumberingVisitor
duke@435	279	void kill_memory() { _too_complicated_loop = true; }
duke@435	280	void kill_field(ciField* field) { current_map()->kill_field(field); };
duke@435	281	void kill_array(ValueType* type) { current_map()->kill_array(type); };
duke@435	282
duke@435	283	public:
duke@435	284	ShortLoopOptimizer(GlobalValueNumbering* gvn)
duke@435	285	: _gvn(gvn)
duke@435	286	, _loop_blocks(ValueMapMaxLoopSize)
duke@435	287	, _too_complicated_loop(false)
duke@435	288	{
duke@435	289	}
duke@435	290
duke@435	291	bool process(BlockBegin* loop_header);
duke@435	292	};
duke@435	293
duke@435	294
duke@435	295	bool ShortLoopOptimizer::process(BlockBegin* loop_header) {
duke@435	296	TRACE_VALUE_NUMBERING(tty->print_cr("** loop header block"));
duke@435	297
duke@435	298	_too_complicated_loop = false;
duke@435	299	_loop_blocks.clear();
duke@435	300	_loop_blocks.append(loop_header);
duke@435	301
duke@435	302	for (int i = 0; i < _loop_blocks.length(); i++) {
duke@435	303	BlockBegin* block = _loop_blocks.at(i);
duke@435	304	TRACE_VALUE_NUMBERING(tty->print_cr("processing loop block B%d", block->block_id()));
duke@435	305
duke@435	306	if (block->is_set(BlockBegin::exception_entry_flag)) {
duke@435	307	// this would be too complicated
duke@435	308	return false;
duke@435	309	}
duke@435	310
duke@435	311	// add predecessors to worklist
duke@435	312	for (int j = block->number_of_preds() - 1; j >= 0; j--) {
duke@435	313	BlockBegin* pred = block->pred_at(j);
duke@435	314
duke@435	315	ValueMap* pred_map = value_map_of(pred);
duke@435	316	if (pred_map != NULL) {
duke@435	317	current_map()->kill_map(pred_map);
duke@435	318	} else if (!_loop_blocks.contains(pred)) {
duke@435	319	if (_loop_blocks.length() >= ValueMapMaxLoopSize) {
duke@435	320	return false;
duke@435	321	}
duke@435	322	_loop_blocks.append(pred);
duke@435	323	}
duke@435	324	}
duke@435	325
duke@435	326	// use the instruction visitor for killing values
duke@435	327	for (Value instr = block->next(); instr != NULL; instr = instr->next()) {
duke@435	328	instr->visit(this);
duke@435	329	if (_too_complicated_loop) {
duke@435	330	return false;
duke@435	331	}
duke@435	332	}
duke@435	333	}
duke@435	334
duke@435	335	TRACE_VALUE_NUMBERING(tty->print_cr("** loop successfully optimized"));
duke@435	336	return true;
duke@435	337	}
duke@435	338
duke@435	339
duke@435	340	GlobalValueNumbering::GlobalValueNumbering(IR* ir)
duke@435	341	: _current_map(NULL)
duke@435	342	, _value_maps(ir->linear_scan_order()->length(), NULL)
duke@435	343	{
duke@435	344	TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering"));
duke@435	345
duke@435	346	ShortLoopOptimizer short_loop_optimizer(this);
duke@435	347	int subst_count = 0;
duke@435	348
duke@435	349	BlockList* blocks = ir->linear_scan_order();
duke@435	350	int num_blocks = blocks->length();
duke@435	351
duke@435	352	BlockBegin* start_block = blocks->at(0);
duke@435	353	assert(start_block == ir->start() && start_block->number_of_preds() == 0 && start_block->dominator() == NULL, "must be start block");
duke@435	354	assert(start_block->next()->as_Base() != NULL && start_block->next()->next() == NULL, "start block must not have instructions");
duke@435	355
duke@435	356	// initial, empty value map with nesting 0
duke@435	357	set_value_map_of(start_block, new ValueMap());
duke@435	358
duke@435	359	for (int i = 1; i < num_blocks; i++) {
duke@435	360	BlockBegin* block = blocks->at(i);
duke@435	361	TRACE_VALUE_NUMBERING(tty->print_cr("**** processing block B%d", block->block_id()));
duke@435	362
duke@435	363	int num_preds = block->number_of_preds();
duke@435	364	assert(num_preds > 0, "block must have predecessors");
duke@435	365
duke@435	366	BlockBegin* dominator = block->dominator();
duke@435	367	assert(dominator != NULL, "dominator must exist");
duke@435	368	assert(value_map_of(dominator) != NULL, "value map of dominator must exist");
duke@435	369
duke@435	370	// create new value map with increased nesting
duke@435	371	_current_map = new ValueMap(value_map_of(dominator));
duke@435	372
duke@435	373	if (num_preds == 1) {
duke@435	374	assert(dominator == block->pred_at(0), "dominator must be equal to predecessor");
duke@435	375	// nothing to do here
duke@435	376
duke@435	377	} else if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
duke@435	378	// block has incoming backward branches -> try to optimize short loops
duke@435	379	if (!short_loop_optimizer.process(block)) {
duke@435	380	// loop is too complicated, so kill all memory loads because there might be
duke@435	381	// stores to them in the loop
duke@435	382	current_map()->kill_memory();
duke@435	383	}
duke@435	384
duke@435	385	} else {
duke@435	386	// only incoming forward branches that are already processed
duke@435	387	for (int j = 0; j < num_preds; j++) {
duke@435	388	BlockBegin* pred = block->pred_at(j);
duke@435	389	ValueMap* pred_map = value_map_of(pred);
duke@435	390
duke@435	391	if (pred_map != NULL) {
duke@435	392	// propagate killed values of the predecessor to this block
duke@435	393	current_map()->kill_map(value_map_of(pred));
duke@435	394	} else {
duke@435	395	// kill all memory loads because predecessor not yet processed
duke@435	396	// (this can happen with non-natural loops and OSR-compiles)
duke@435	397	current_map()->kill_memory();
duke@435	398	}
duke@435	399	}
duke@435	400	}
duke@435	401
duke@435	402	if (block->is_set(BlockBegin::exception_entry_flag)) {
duke@435	403	current_map()->kill_exception();
duke@435	404	}
duke@435	405
duke@435	406	TRACE_VALUE_NUMBERING(tty->print("value map before processing block: "); current_map()->print());
duke@435	407
duke@435	408	// visit all instructions of this block
duke@435	409	for (Value instr = block->next(); instr != NULL; instr = instr->next()) {
duke@435	410	assert(!instr->has_subst(), "substitution already set");
duke@435	411
duke@435	412	// check if instruction kills any values
duke@435	413	instr->visit(this);
duke@435	414
duke@435	415	if (instr->hash() != 0) {
duke@435	416	Value f = current_map()->find_insert(instr);
duke@435	417	if (f != instr) {
duke@435	418	assert(!f->has_subst(), "can't have a substitution");
duke@435	419	instr->set_subst(f);
duke@435	420	subst_count++;
duke@435	421	}
duke@435	422	}
duke@435	423	}
duke@435	424
duke@435	425	// remember value map for successors
duke@435	426	set_value_map_of(block, current_map());
duke@435	427	}
duke@435	428
duke@435	429	if (subst_count != 0) {
duke@435	430	SubstitutionResolver resolver(ir);
duke@435	431	}
duke@435	432
duke@435	433	TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics());
duke@435	434	}