| /* |
| * Copyright (c) 1999, 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "c1/c1_Canonicalizer.hpp" |
| #include "c1/c1_IR.hpp" |
| #include "c1/c1_ValueMap.hpp" |
| #include "c1/c1_ValueStack.hpp" |
| #include "utilities/bitMap.inline.hpp" |
| |
| #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); |
| } |
| assert(x->type()->tag() == f->type()->tag(), "should have same type"); |
| |
| 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() \ |
| && (all_offsets || lf->field()->offset() == field->offset()); |
| |
| |
| 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, bool all_offsets) { |
| GENERIC_KILL_VALUE(MUST_KILL_FIELD); |
| } |
| |
| 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; |
| bool _has_field_store[T_ARRAY + 1]; |
| bool _has_indexed_store[T_ARRAY + 1]; |
| |
| // 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, bool all_offsets) { |
| current_map()->kill_field(field, all_offsets); |
| assert(field->type()->basic_type() >= 0 && field->type()->basic_type() <= T_ARRAY, "Invalid type"); |
| _has_field_store[field->type()->basic_type()] = true; |
| } |
| void kill_array(ValueType* type) { |
| current_map()->kill_array(type); |
| BasicType basic_type = as_BasicType(type); assert(basic_type >= 0 && basic_type <= T_ARRAY, "Invalid type"); |
| _has_indexed_store[basic_type] = true; |
| } |
| |
| public: |
| ShortLoopOptimizer(GlobalValueNumbering* gvn) |
| : _gvn(gvn) |
| , _loop_blocks(ValueMapMaxLoopSize) |
| , _too_complicated_loop(false) |
| { |
| for (int i=0; i<= T_ARRAY; i++){ |
| _has_field_store[i] = false; |
| _has_indexed_store[i] = false; |
| } |
| } |
| |
| bool has_field_store(BasicType type) { |
| assert(type >= 0 && type <= T_ARRAY, "Invalid type"); |
| return _has_field_store[type]; |
| } |
| |
| bool has_indexed_store(BasicType type) { |
| assert(type >= 0 && type <= T_ARRAY, "Invalid type"); |
| return _has_indexed_store[type]; |
| } |
| |
| bool process(BlockBegin* loop_header); |
| }; |
| |
| class LoopInvariantCodeMotion : public StackObj { |
| private: |
| GlobalValueNumbering* _gvn; |
| ShortLoopOptimizer* _short_loop_optimizer; |
| Instruction* _insertion_point; |
| ValueStack * _state; |
| bool _insert_is_pred; |
| |
| void set_invariant(Value v) const { _gvn->set_processed(v); } |
| bool is_invariant(Value v) const { return _gvn->is_processed(v); } |
| |
| void process_block(BlockBegin* block); |
| |
| public: |
| LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks); |
| }; |
| |
| LoopInvariantCodeMotion::LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks) |
| : _gvn(gvn), _short_loop_optimizer(slo) { |
| |
| TRACE_VALUE_NUMBERING(tty->print_cr("using loop invariant code motion loop_header = %d", loop_header->block_id())); |
| TRACE_VALUE_NUMBERING(tty->print_cr("** loop invariant code motion for short loop B%d", loop_header->block_id())); |
| |
| BlockBegin* insertion_block = loop_header->dominator(); |
| if (insertion_block->number_of_preds() == 0) { |
| return; // only the entry block does not have a predecessor |
| } |
| |
| assert(insertion_block->end()->as_Base() == NULL, "cannot insert into entry block"); |
| _insertion_point = insertion_block->end()->prev(); |
| _insert_is_pred = loop_header->is_predecessor(insertion_block); |
| |
| BlockEnd *block_end = insertion_block->end(); |
| _state = block_end->state_before(); |
| |
| if (!_state) { |
| // If, TableSwitch and LookupSwitch always have state_before when |
| // loop invariant code motion happens.. |
| assert(block_end->as_Goto(), "Block has to be goto"); |
| _state = block_end->state(); |
| } |
| |
| // the loop_blocks are filled by going backward from the loop header, so this processing order is best |
| assert(loop_blocks->at(0) == loop_header, "loop header must be first loop block"); |
| process_block(loop_header); |
| for (int i = loop_blocks->length() - 1; i >= 1; i--) { |
| process_block(loop_blocks->at(i)); |
| } |
| } |
| |
| void LoopInvariantCodeMotion::process_block(BlockBegin* block) { |
| TRACE_VALUE_NUMBERING(tty->print_cr("processing block B%d", block->block_id())); |
| |
| Instruction* prev = block; |
| Instruction* cur = block->next(); |
| |
| while (cur != NULL) { |
| |
| // determine if cur instruction is loop invariant |
| // only selected instruction types are processed here |
| bool cur_invariant = false; |
| |
| if (cur->as_Constant() != NULL) { |
| cur_invariant = !cur->can_trap(); |
| } else if (cur->as_ArithmeticOp() != NULL || cur->as_LogicOp() != NULL || cur->as_ShiftOp() != NULL) { |
| assert(cur->as_Op2() != NULL, "must be Op2"); |
| Op2* op2 = (Op2*)cur; |
| cur_invariant = !op2->can_trap() && is_invariant(op2->x()) && is_invariant(op2->y()); |
| } else if (cur->as_LoadField() != NULL) { |
| LoadField* lf = (LoadField*)cur; |
| // deoptimizes on NullPointerException |
| cur_invariant = !lf->needs_patching() && !lf->field()->is_volatile() && !_short_loop_optimizer->has_field_store(lf->field()->type()->basic_type()) && is_invariant(lf->obj()) && _insert_is_pred; |
| } else if (cur->as_ArrayLength() != NULL) { |
| ArrayLength *length = cur->as_ArrayLength(); |
| cur_invariant = is_invariant(length->array()); |
| } else if (cur->as_LoadIndexed() != NULL) { |
| LoadIndexed *li = (LoadIndexed *)cur->as_LoadIndexed(); |
| cur_invariant = !_short_loop_optimizer->has_indexed_store(as_BasicType(cur->type())) && is_invariant(li->array()) && is_invariant(li->index()) && _insert_is_pred; |
| } |
| |
| if (cur_invariant) { |
| // perform value numbering and mark instruction as loop-invariant |
| _gvn->substitute(cur); |
| |
| if (cur->as_Constant() == NULL) { |
| // ensure that code for non-constant instructions is always generated |
| cur->pin(); |
| } |
| |
| // remove cur instruction from loop block and append it to block before loop |
| Instruction* next = cur->next(); |
| Instruction* in = _insertion_point->next(); |
| _insertion_point = _insertion_point->set_next(cur); |
| cur->set_next(in); |
| |
| // Deoptimize on exception |
| cur->set_flag(Instruction::DeoptimizeOnException, true); |
| |
| // Clear exception handlers |
| cur->set_exception_handlers(NULL); |
| |
| TRACE_VALUE_NUMBERING(tty->print_cr("Instruction %c%d is loop invariant", cur->type()->tchar(), cur->id())); |
| |
| if (cur->state_before() != NULL) { |
| cur->set_state_before(_state->copy()); |
| } |
| if (cur->exception_state() != NULL) { |
| cur->set_exception_state(_state->copy()); |
| } |
| |
| cur = prev->set_next(next); |
| |
| } else { |
| prev = cur; |
| cur = cur->next(); |
| } |
| } |
| } |
| |
| 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); |
| |
| if (pred->is_set(BlockBegin::osr_entry_flag)) { |
| return false; |
| } |
| |
| 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; |
| } |
| } |
| } |
| |
| bool optimistic = this->_gvn->compilation()->is_optimistic(); |
| |
| if (UseLoopInvariantCodeMotion && optimistic) { |
| LoopInvariantCodeMotion code_motion(this, _gvn, loop_header, &_loop_blocks); |
| } |
| |
| 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) |
| , _compilation(ir->compilation()) |
| { |
| TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering")); |
| |
| ShortLoopOptimizer short_loop_optimizer(this); |
| |
| 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"); |
| |
| // method parameters are not linked in instructions list, so process them separateley |
| for_each_state_value(start_block->state(), value, |
| assert(value->as_Local() != NULL, "only method parameters allowed"); |
| set_processed(value); |
| ); |
| |
| // 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 && !block->is_set(BlockBegin::exception_entry_flag)) { |
| 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(); |
| } |
| } |
| } |
| |
| // phi functions are not linked in instructions list, so process them separateley |
| for_each_phi_fun(block, phi, |
| set_processed(phi); |
| ); |
| |
| 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()) { |
| // check if instruction kills any values |
| instr->visit(this); |
| // perform actual value numbering |
| substitute(instr); |
| } |
| |
| // remember value map for successors |
| set_value_map_of(block, current_map()); |
| } |
| |
| if (_has_substitutions) { |
| SubstitutionResolver resolver(ir); |
| } |
| |
| TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics()); |
| } |
| |
| void GlobalValueNumbering::substitute(Instruction* instr) { |
| assert(!instr->has_subst(), "substitution already set"); |
| Value subst = current_map()->find_insert(instr); |
| if (subst != instr) { |
| assert(!subst->has_subst(), "can't have a substitution"); |
| |
| TRACE_VALUE_NUMBERING(tty->print_cr("substitution for %d set to %d", instr->id(), subst->id())); |
| instr->set_subst(subst); |
| _has_substitutions = true; |
| } |
| set_processed(instr); |
| } |