Mercurial > hg > truffle
diff src/share/vm/c1/c1_ValueMap.cpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | c18cbe5936b8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/c1/c1_ValueMap.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,434 @@ +/* + * Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +#include "incls/_precompiled.incl" +#include "incls/_c1_ValueMap.cpp.incl" + + +#ifndef PRODUCT + + int ValueMap::_number_of_finds = 0; + int ValueMap::_number_of_hits = 0; + int ValueMap::_number_of_kills = 0; + + #define TRACE_VALUE_NUMBERING(code) if (PrintValueNumbering) { code; } + +#else + + #define TRACE_VALUE_NUMBERING(code) + +#endif + + +ValueMap::ValueMap() + : _nesting(0) + , _entries(ValueMapInitialSize, NULL) + , _killed_values() + , _entry_count(0) +{ + NOT_PRODUCT(reset_statistics()); +} + + +ValueMap::ValueMap(ValueMap* old) + : _nesting(old->_nesting + 1) + , _entries(old->_entries.length()) + , _killed_values() + , _entry_count(old->_entry_count) +{ + for (int i = size() - 1; i >= 0; i--) { + _entries.at_put(i, old->entry_at(i)); + } + _killed_values.set_from(&old->_killed_values); +} + + +void ValueMap::increase_table_size() { + int old_size = size(); + int new_size = old_size * 2 + 1; + + ValueMapEntryList worklist(8); + ValueMapEntryArray new_entries(new_size, NULL); + int new_entry_count = 0; + + TRACE_VALUE_NUMBERING(tty->print_cr("increasing table size from %d to %d", old_size, new_size)); + + for (int i = old_size - 1; i >= 0; i--) { + ValueMapEntry* entry; + for (entry = entry_at(i); entry != NULL; entry = entry->next()) { + if (!is_killed(entry->value())) { + worklist.push(entry); + } + } + + while (!worklist.is_empty()) { + entry = worklist.pop(); + int new_index = entry_index(entry->hash(), new_size); + + if (entry->nesting() != nesting() && new_entries.at(new_index) != entry->next()) { + // changing entries with a lower nesting than the current nesting of the table + // is not allowed because then the same entry is contained in multiple value maps. + // clone entry when next-pointer must be changed + entry = new ValueMapEntry(entry->hash(), entry->value(), entry->nesting(), NULL); + } + entry->set_next(new_entries.at(new_index)); + new_entries.at_put(new_index, entry); + new_entry_count++; + } + } + + _entries = new_entries; + _entry_count = new_entry_count; +} + + +Value ValueMap::find_insert(Value x) { + const intx hash = x->hash(); + if (hash != 0) { + // 0 hash means: exclude from value numbering + NOT_PRODUCT(_number_of_finds++); + + for (ValueMapEntry* entry = entry_at(entry_index(hash, size())); entry != NULL; entry = entry->next()) { + if (entry->hash() == hash) { + Value f = entry->value(); + + if (!is_killed(f) && f->is_equal(x)) { + NOT_PRODUCT(_number_of_hits++); + 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())); + + if (entry->nesting() != nesting() && f->as_Constant() == NULL) { + // non-constant values of of another block must be pinned, + // otherwise it is possible that they are not evaluated + f->pin(Instruction::PinGlobalValueNumbering); + } + + return f; + + } + } + } + + // x not found, so insert it + if (entry_count() >= size_threshold()) { + increase_table_size(); + } + int idx = entry_index(hash, size()); + _entries.at_put(idx, new ValueMapEntry(hash, x, nesting(), entry_at(idx))); + _entry_count++; + + 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())); + } + + return x; +} + + +#define GENERIC_KILL_VALUE(must_kill_implementation) \ + NOT_PRODUCT(_number_of_kills++); \ + \ + for (int i = size() - 1; i >= 0; i--) { \ + ValueMapEntry* prev_entry = NULL; \ + for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { \ + Value value = entry->value(); \ + \ + must_kill_implementation(must_kill, entry, value) \ + \ + if (must_kill) { \ + kill_value(value); \ + \ + if (prev_entry == NULL) { \ + _entries.at_put(i, entry->next()); \ + _entry_count--; \ + } else if (prev_entry->nesting() == nesting()) { \ + prev_entry->set_next(entry->next()); \ + _entry_count--; \ + } else { \ + prev_entry = entry; \ + } \ + \ + 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())); \ + } else { \ + prev_entry = entry; \ + } \ + } \ + } \ + +#define MUST_KILL_MEMORY(must_kill, entry, value) \ + bool must_kill = value->as_LoadField() != NULL || value->as_LoadIndexed() != NULL; + +#define MUST_KILL_ARRAY(must_kill, entry, value) \ + bool must_kill = value->as_LoadIndexed() != NULL \ + && value->type()->tag() == type->tag(); + +#define MUST_KILL_FIELD(must_kill, entry, value) \ + /* ciField's are not unique; must compare their contents */ \ + LoadField* lf = value->as_LoadField(); \ + bool must_kill = lf != NULL \ + && lf->field()->holder() == field->holder() \ + && lf->field()->offset() == field->offset(); + +#define MUST_KILL_EXCEPTION(must_kill, entry, value) \ + assert(entry->nesting() < nesting(), "must not find bigger nesting than current"); \ + bool must_kill = (entry->nesting() == nesting() - 1); + + +void ValueMap::kill_memory() { + GENERIC_KILL_VALUE(MUST_KILL_MEMORY); +} + +void ValueMap::kill_array(ValueType* type) { + GENERIC_KILL_VALUE(MUST_KILL_ARRAY); +} + +void ValueMap::kill_field(ciField* field) { + GENERIC_KILL_VALUE(MUST_KILL_FIELD); +} + +void ValueMap::kill_exception() { + GENERIC_KILL_VALUE(MUST_KILL_EXCEPTION); +} + + +void ValueMap::kill_map(ValueMap* map) { + assert(is_global_value_numbering(), "only for global value numbering"); + _killed_values.set_union(&map->_killed_values); +} + +void ValueMap::kill_all() { + assert(is_local_value_numbering(), "only for local value numbering"); + for (int i = size() - 1; i >= 0; i--) { + _entries.at_put(i, NULL); + } + _entry_count = 0; +} + + +#ifndef PRODUCT + +void ValueMap::print() { + tty->print_cr("(size %d, entries %d, nesting %d)", size(), entry_count(), nesting()); + + int entries = 0; + for (int i = 0; i < size(); i++) { + if (entry_at(i) != NULL) { + tty->print(" %2d: ", i); + for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { + Value value = entry->value(); + tty->print("%s %c%d (%s%d) -> ", value->name(), value->type()->tchar(), value->id(), is_killed(value) ? "x" : "", entry->nesting()); + entries++; + } + tty->print_cr("NULL"); + } + } + + _killed_values.print(); + assert(entry_count() == entries, "entry_count incorrect"); +} + +void ValueMap::reset_statistics() { + _number_of_finds = 0; + _number_of_hits = 0; + _number_of_kills = 0; +} + +void ValueMap::print_statistics() { + float hit_rate = 0; + if (_number_of_finds != 0) { + hit_rate = (float)_number_of_hits / _number_of_finds; + } + + tty->print_cr("finds:%3d hits:%3d kills:%3d hit rate: %1.4f", _number_of_finds, _number_of_hits, _number_of_kills, hit_rate); +} + +#endif + + + +class ShortLoopOptimizer : public ValueNumberingVisitor { + private: + GlobalValueNumbering* _gvn; + BlockList _loop_blocks; + bool _too_complicated_loop; + + // simplified access to methods of GlobalValueNumbering + ValueMap* current_map() { return _gvn->current_map(); } + ValueMap* value_map_of(BlockBegin* block) { return _gvn->value_map_of(block); } + + // implementation for abstract methods of ValueNumberingVisitor + void kill_memory() { _too_complicated_loop = true; } + void kill_field(ciField* field) { current_map()->kill_field(field); }; + void kill_array(ValueType* type) { current_map()->kill_array(type); }; + + public: + ShortLoopOptimizer(GlobalValueNumbering* gvn) + : _gvn(gvn) + , _loop_blocks(ValueMapMaxLoopSize) + , _too_complicated_loop(false) + { + } + + bool process(BlockBegin* loop_header); +}; + + +bool ShortLoopOptimizer::process(BlockBegin* loop_header) { + TRACE_VALUE_NUMBERING(tty->print_cr("** loop header block")); + + _too_complicated_loop = false; + _loop_blocks.clear(); + _loop_blocks.append(loop_header); + + for (int i = 0; i < _loop_blocks.length(); i++) { + BlockBegin* block = _loop_blocks.at(i); + TRACE_VALUE_NUMBERING(tty->print_cr("processing loop block B%d", block->block_id())); + + if (block->is_set(BlockBegin::exception_entry_flag)) { + // this would be too complicated + return false; + } + + // add predecessors to worklist + for (int j = block->number_of_preds() - 1; j >= 0; j--) { + BlockBegin* pred = block->pred_at(j); + + ValueMap* pred_map = value_map_of(pred); + if (pred_map != NULL) { + current_map()->kill_map(pred_map); + } else if (!_loop_blocks.contains(pred)) { + if (_loop_blocks.length() >= ValueMapMaxLoopSize) { + return false; + } + _loop_blocks.append(pred); + } + } + + // use the instruction visitor for killing values + for (Value instr = block->next(); instr != NULL; instr = instr->next()) { + instr->visit(this); + if (_too_complicated_loop) { + return false; + } + } + } + + TRACE_VALUE_NUMBERING(tty->print_cr("** loop successfully optimized")); + return true; +} + + +GlobalValueNumbering::GlobalValueNumbering(IR* ir) + : _current_map(NULL) + , _value_maps(ir->linear_scan_order()->length(), NULL) +{ + TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering")); + + ShortLoopOptimizer short_loop_optimizer(this); + int subst_count = 0; + + BlockList* blocks = ir->linear_scan_order(); + int num_blocks = blocks->length(); + + BlockBegin* start_block = blocks->at(0); + assert(start_block == ir->start() && start_block->number_of_preds() == 0 && start_block->dominator() == NULL, "must be start block"); + assert(start_block->next()->as_Base() != NULL && start_block->next()->next() == NULL, "start block must not have instructions"); + + // initial, empty value map with nesting 0 + set_value_map_of(start_block, new ValueMap()); + + for (int i = 1; i < num_blocks; i++) { + BlockBegin* block = blocks->at(i); + TRACE_VALUE_NUMBERING(tty->print_cr("**** processing block B%d", block->block_id())); + + int num_preds = block->number_of_preds(); + assert(num_preds > 0, "block must have predecessors"); + + BlockBegin* dominator = block->dominator(); + assert(dominator != NULL, "dominator must exist"); + assert(value_map_of(dominator) != NULL, "value map of dominator must exist"); + + // create new value map with increased nesting + _current_map = new ValueMap(value_map_of(dominator)); + + if (num_preds == 1) { + assert(dominator == block->pred_at(0), "dominator must be equal to predecessor"); + // nothing to do here + + } else if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) { + // block has incoming backward branches -> try to optimize short loops + if (!short_loop_optimizer.process(block)) { + // loop is too complicated, so kill all memory loads because there might be + // stores to them in the loop + current_map()->kill_memory(); + } + + } else { + // only incoming forward branches that are already processed + for (int j = 0; j < num_preds; j++) { + BlockBegin* pred = block->pred_at(j); + ValueMap* pred_map = value_map_of(pred); + + if (pred_map != NULL) { + // propagate killed values of the predecessor to this block + current_map()->kill_map(value_map_of(pred)); + } else { + // kill all memory loads because predecessor not yet processed + // (this can happen with non-natural loops and OSR-compiles) + current_map()->kill_memory(); + } + } + } + + if (block->is_set(BlockBegin::exception_entry_flag)) { + current_map()->kill_exception(); + } + + TRACE_VALUE_NUMBERING(tty->print("value map before processing block: "); current_map()->print()); + + // visit all instructions of this block + for (Value instr = block->next(); instr != NULL; instr = instr->next()) { + assert(!instr->has_subst(), "substitution already set"); + + // check if instruction kills any values + instr->visit(this); + + if (instr->hash() != 0) { + Value f = current_map()->find_insert(instr); + if (f != instr) { + assert(!f->has_subst(), "can't have a substitution"); + instr->set_subst(f); + subst_count++; + } + } + } + + // remember value map for successors + set_value_map_of(block, current_map()); + } + + if (subst_count != 0) { + SubstitutionResolver resolver(ir); + } + + TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics()); +}