# HG changeset patch # User never # Date 1221681592 25200 # Node ID 194b8e3a2fc4cbee8f16ddad5ba22d4d4d40393f # Parent 8261ee795323bd4d66a8a84fa44c36dca034016c 6384206: Phis which are later unneeded are impairing our ability to inline based on static types Reviewed-by: rasbold, jrose diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/ci/ciMethodBlocks.cpp --- a/src/share/vm/ci/ciMethodBlocks.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/ci/ciMethodBlocks.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -49,7 +49,7 @@ // first half. Returns the range beginning at bci. ciBlock *ciMethodBlocks::split_block_at(int bci) { ciBlock *former_block = block_containing(bci); - ciBlock *new_block = new(_arena) ciBlock(_method, _num_blocks++, this, former_block->start_bci()); + ciBlock *new_block = new(_arena) ciBlock(_method, _num_blocks++, former_block->start_bci()); _blocks->append(new_block); assert(former_block != NULL, "must not be NULL"); new_block->set_limit_bci(bci); @@ -83,7 +83,7 @@ if (cb == NULL ) { // This is our first time visiting this bytecode. Create // a fresh block and assign it this starting point. - ciBlock *nb = new(_arena) ciBlock(_method, _num_blocks++, this, bci); + ciBlock *nb = new(_arena) ciBlock(_method, _num_blocks++, bci); _blocks->append(nb); _bci_to_block[bci] = nb; return nb; @@ -98,6 +98,11 @@ } } +ciBlock *ciMethodBlocks::make_dummy_block() { + ciBlock *dum = new(_arena) ciBlock(_method, -1, 0); + return dum; +} + void ciMethodBlocks::do_analysis() { ciBytecodeStream s(_method); ciBlock *cur_block = block_containing(0); @@ -253,7 +258,7 @@ Copy::zero_to_words((HeapWord*) _bci_to_block, b2bsize / sizeof(HeapWord)); // create initial block covering the entire method - ciBlock *b = new(arena) ciBlock(_method, _num_blocks++, this, 0); + ciBlock *b = new(arena) ciBlock(_method, _num_blocks++, 0); _blocks->append(b); _bci_to_block[0] = b; @@ -334,7 +339,7 @@ #endif -ciBlock::ciBlock(ciMethod *method, int index, ciMethodBlocks *mb, int start_bci) : +ciBlock::ciBlock(ciMethod *method, int index, int start_bci) : #ifndef PRODUCT _method(method), #endif diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/ci/ciMethodBlocks.hpp --- a/src/share/vm/ci/ciMethodBlocks.hpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/ci/ciMethodBlocks.hpp Wed Sep 17 12:59:52 2008 -0700 @@ -48,6 +48,8 @@ int num_blocks() { return _num_blocks;} void clear_processed(); + ciBlock *make_dummy_block(); // a block not associated with a bci + #ifndef PRODUCT void dump(); #endif @@ -81,7 +83,7 @@ fall_through_bci = -1 }; - ciBlock(ciMethod *method, int index, ciMethodBlocks *mb, int start_bci); + ciBlock(ciMethod *method, int index, int start_bci); int start_bci() const { return _start_bci; } int limit_bci() const { return _limit_bci; } int control_bci() const { return _control_bci; } @@ -94,7 +96,6 @@ int ex_limit_bci() const { return _ex_limit_bci; } bool contains(int bci) const { return start_bci() <= bci && bci < limit_bci(); } - // flag handling bool processed() const { return (_flags & Processed) != 0; } bool is_handler() const { return (_flags & Handler) != 0; } diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/ci/ciTypeFlow.cpp --- a/src/share/vm/ci/ciTypeFlow.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/ci/ciTypeFlow.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -338,8 +338,10 @@ } _trap_bci = -1; _trap_index = 0; + _def_locals.clear(); } + // ------------------------------------------------------------------ // ciTypeFlow::get_start_state // @@ -735,7 +737,7 @@ void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) { bool will_link; ciKlass* klass = str->get_klass(will_link); - if (!will_link) { + if (!will_link || str->is_unresolved_klass()) { trap(str, klass, str->get_klass_index()); } else { push_object(klass); @@ -1268,7 +1270,9 @@ } case Bytecodes::_iinc: { - check_int(local(str->get_index())); + int lnum = str->get_index(); + check_int(local(lnum)); + store_to_local(lnum); break; } case Bytecodes::_iload: load_local_int(str->get_index()); break; @@ -1506,6 +1510,46 @@ } #endif + +// ------------------------------------------------------------------ +// ciTypeFlow::SuccIter::next +// +void ciTypeFlow::SuccIter::next() { + int succ_ct = _pred->successors()->length(); + int next = _index + 1; + if (next < succ_ct) { + _index = next; + _succ = _pred->successors()->at(next); + return; + } + for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) { + // Do not compile any code for unloaded exception types. + // Following compiler passes are responsible for doing this also. + ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i); + if (exception_klass->is_loaded()) { + _index = next; + _succ = _pred->exceptions()->at(i); + return; + } + next++; + } + _index = -1; + _succ = NULL; +} + +// ------------------------------------------------------------------ +// ciTypeFlow::SuccIter::set_succ +// +void ciTypeFlow::SuccIter::set_succ(Block* succ) { + int succ_ct = _pred->successors()->length(); + if (_index < succ_ct) { + _pred->successors()->at_put(_index, succ); + } else { + int idx = _index - succ_ct; + _pred->exceptions()->at_put(idx, succ); + } +} + // ciTypeFlow::Block // // A basic block. @@ -1526,10 +1570,11 @@ _jsrs = new_jsrs; _next = NULL; _on_work_list = false; - _pre_order = -1; assert(!has_pre_order(), ""); - _private_copy = false; + _backedge_copy = false; + _exception_entry = false; _trap_bci = -1; _trap_index = 0; + df_init(); if (CITraceTypeFlow) { tty->print_cr(">> Created new block"); @@ -1541,55 +1586,13 @@ } // ------------------------------------------------------------------ -// ciTypeFlow::Block::clone_loop_head -// -ciTypeFlow::Block* -ciTypeFlow::Block::clone_loop_head(ciTypeFlow* analyzer, - int branch_bci, - ciTypeFlow::Block* target, - ciTypeFlow::JsrSet* jsrs) { - // Loop optimizations are not performed on Tier1 compiles. Do nothing. - if (analyzer->env()->comp_level() < CompLevel_full_optimization) { - return target; - } - - // The current block ends with a branch. - // - // If the target block appears to be the test-clause of a for loop, and - // it is not too large, and it has not yet been cloned, clone it. - // The pre-existing copy becomes the private clone used only by - // the initial iteration of the loop. (We know we are simulating - // the initial iteration right now, since we have never calculated - // successors before for this block.) - - if (branch_bci <= start() - && (target->limit() - target->start()) <= CICloneLoopTestLimit - && target->private_copy_count() == 0) { - // Setting the private_copy bit ensures that the target block cannot be - // reached by any other paths, such as fall-in from the loop body. - // The private copy will be accessible only on successor lists - // created up to this point. - target->set_private_copy(true); - if (CITraceTypeFlow) { - tty->print(">> Cloning a test-clause block "); - print_value_on(tty); - tty->cr(); - } - // If the target is the current block, then later on a new copy of the - // target block will be created when its bytecodes are reached by - // an alternate path. (This is the case for loops with the loop - // head at the bci-wise bottom of the loop, as with pre-1.4.2 javac.) - // - // Otherwise, duplicate the target block now and use it immediately. - // (The case for loops with the loop head at the bci-wise top of the - // loop, as with 1.4.2 javac.) - // - // In either case, the new copy of the block will remain public. - if (target != this) { - target = analyzer->block_at(branch_bci, jsrs); - } - } - return target; +// ciTypeFlow::Block::df_init +void ciTypeFlow::Block::df_init() { + _pre_order = -1; assert(!has_pre_order(), ""); + _post_order = -1; assert(!has_post_order(), ""); + _loop = NULL; + _irreducible_entry = false; + _rpo_next = NULL; } // ------------------------------------------------------------------ @@ -1644,7 +1647,6 @@ case Bytecodes::_ifnull: case Bytecodes::_ifnonnull: // Our successors are the branch target and the next bci. branch_bci = str->get_dest(); - clone_loop_head(analyzer, branch_bci, this, jsrs); _successors = new (arena) GrowableArray(arena, 2, 0, NULL); assert(_successors->length() == IF_NOT_TAKEN, ""); @@ -1658,14 +1660,7 @@ _successors = new (arena) GrowableArray(arena, 1, 0, NULL); assert(_successors->length() == GOTO_TARGET, ""); - target = analyzer->block_at(branch_bci, jsrs); - // If the target block has not been visited yet, and looks like - // a two-way branch, attempt to clone it if it is a loop head. - if (target->_successors != NULL - && target->_successors->length() == (IF_TAKEN + 1)) { - target = clone_loop_head(analyzer, branch_bci, target, jsrs); - } - _successors->append(target); + _successors->append(analyzer->block_at(branch_bci, jsrs)); break; case Bytecodes::_jsr: @@ -1801,65 +1796,60 @@ } // ------------------------------------------------------------------ -// ciTypeFlow::Block::is_simpler_than -// -// A relation used to order our work list. We work on a block earlier -// if it has a smaller jsr stack or it occurs earlier in the program -// text. -// -// Note: maybe we should redo this functionality to make blocks -// which correspond to exceptions lower priority. -bool ciTypeFlow::Block::is_simpler_than(ciTypeFlow::Block* other) { - if (other == NULL) { - return true; - } else { - int size1 = _jsrs->size(); - int size2 = other->_jsrs->size(); - if (size1 < size2) { - return true; - } else if (size2 < size1) { - return false; - } else { -#if 0 - if (size1 > 0) { - int r1 = _jsrs->record_at(0)->return_address(); - int r2 = _jsrs->record_at(0)->return_address(); - if (r1 < r2) { - return true; - } else if (r2 < r1) { - return false; - } else { - int e1 = _jsrs->record_at(0)->return_address(); - int e2 = _jsrs->record_at(0)->return_address(); - if (e1 < e2) { - return true; - } else if (e2 < e1) { - return false; - } - } - } -#endif - return (start() <= other->start()); - } - } +// ciTypeFlow::Block::set_backedge_copy +// Use this only to make a pre-existing public block into a backedge copy. +void ciTypeFlow::Block::set_backedge_copy(bool z) { + assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public"); + _backedge_copy = z; } // ------------------------------------------------------------------ -// ciTypeFlow::Block::set_private_copy -// Use this only to make a pre-existing public block into a private copy. -void ciTypeFlow::Block::set_private_copy(bool z) { - assert(z || (z == is_private_copy()), "cannot make a private copy public"); - _private_copy = z; +// ciTypeFlow::Block::is_clonable_exit +// +// At most 2 normal successors, one of which continues looping, +// and all exceptional successors must exit. +bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) { + int normal_cnt = 0; + int in_loop_cnt = 0; + for (SuccIter iter(this); !iter.done(); iter.next()) { + Block* succ = iter.succ(); + if (iter.is_normal_ctrl()) { + if (++normal_cnt > 2) return false; + if (lp->contains(succ->loop())) { + if (++in_loop_cnt > 1) return false; + } + } else { + if (lp->contains(succ->loop())) return false; + } + } + return in_loop_cnt == 1; +} + +// ------------------------------------------------------------------ +// ciTypeFlow::Block::looping_succ +// +ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) { + assert(successors()->length() <= 2, "at most 2 normal successors"); + for (SuccIter iter(this); !iter.done(); iter.next()) { + Block* succ = iter.succ(); + if (lp->contains(succ->loop())) { + return succ; + } + } + return NULL; } #ifndef PRODUCT // ------------------------------------------------------------------ // ciTypeFlow::Block::print_value_on void ciTypeFlow::Block::print_value_on(outputStream* st) const { - if (has_pre_order()) st->print("#%-2d ", pre_order()); + if (has_pre_order()) st->print("#%-2d ", pre_order()); + if (has_rpo()) st->print("rpo#%-2d ", rpo()); st->print("[%d - %d)", start(), limit()); + if (is_loop_head()) st->print(" lphd"); + if (is_irreducible_entry()) st->print(" irred"); if (_jsrs->size() > 0) { st->print("/"); _jsrs->print_on(st); } - if (is_private_copy()) st->print("/private_copy"); + if (is_backedge_copy()) st->print("/backedge_copy"); } // ------------------------------------------------------------------ @@ -1871,6 +1861,16 @@ st->print_cr(" ==================================================== "); st->print (" "); print_value_on(st); + st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr(); + if (loop() && loop()->parent() != NULL) { + st->print(" loops:"); + Loop* lp = loop(); + do { + st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order()); + if (lp->is_irreducible()) st->print("(ir)"); + lp = lp->parent(); + } while (lp->parent() != NULL); + } st->cr(); _state->print_on(st); if (_successors == NULL) { @@ -1907,6 +1907,21 @@ } #endif +#ifndef PRODUCT +// ------------------------------------------------------------------ +// ciTypeFlow::LocalSet::print_on +void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const { + st->print("{"); + for (int i = 0; i < max; i++) { + if (test(i)) st->print(" %d", i); + } + if (limit > max) { + st->print(" %d..%d ", max, limit); + } + st->print(" }"); +} +#endif + // ciTypeFlow // // This is a pass over the bytecodes which computes the following: @@ -1922,12 +1937,11 @@ _max_locals = method->max_locals(); _max_stack = method->max_stack(); _code_size = method->code_size(); + _has_irreducible_entry = false; _osr_bci = osr_bci; _failure_reason = NULL; assert(start_bci() >= 0 && start_bci() < code_size() , "correct osr_bci argument"); - _work_list = NULL; - _next_pre_order = 0; _ciblock_count = _methodBlocks->num_blocks(); _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray*, _ciblock_count); @@ -1949,12 +1963,6 @@ _work_list = next_block->next(); next_block->set_next(NULL); next_block->set_on_work_list(false); - if (!next_block->has_pre_order()) { - // Assign "pre_order" as each new block is taken from the work list. - // This number may be used by following phases to order block visits. - assert(!have_block_count(), "must not have mapped blocks yet") - next_block->set_pre_order(_next_pre_order++); - } return next_block; } @@ -1962,30 +1970,37 @@ // ciTypeFlow::add_to_work_list // // Add a basic block to our work list. +// List is sorted by decreasing postorder sort (same as increasing RPO) void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) { assert(!block->is_on_work_list(), "must not already be on work list"); if (CITraceTypeFlow) { - tty->print(">> Adding block%s ", block->has_pre_order() ? " (again)" : ""); + tty->print(">> Adding block "); block->print_value_on(tty); tty->print_cr(" to the work list : "); } block->set_on_work_list(true); - if (block->is_simpler_than(_work_list)) { + + // decreasing post order sort + + Block* prev = NULL; + Block* current = _work_list; + int po = block->post_order(); + while (current != NULL) { + if (!current->has_post_order() || po > current->post_order()) + break; + prev = current; + current = current->next(); + } + if (prev == NULL) { block->set_next(_work_list); _work_list = block; } else { - Block *temp = _work_list; - while (!block->is_simpler_than(temp->next())) { - if (CITraceTypeFlow) { - tty->print("."); - } - temp = temp->next(); - } - block->set_next(temp->next()); - temp->set_next(block); + block->set_next(current); + prev->set_next(block); } + if (CITraceTypeFlow) { tty->cr(); } @@ -2008,7 +2023,7 @@ assert(ciblk->start_bci() == bci, "bad ciBlock boundaries"); Block* block = get_block_for(ciblk->index(), jsrs, option); - assert(block == NULL? (option == no_create): block->is_private_copy() == (option == create_private_copy), "create option consistent with result"); + assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result"); if (CITraceTypeFlow) { if (block != NULL) { @@ -2072,8 +2087,9 @@ } if (block->meet_exception(exception_klass, state)) { - // Block was modified. Add it to the work list. - if (!block->is_on_work_list()) { + // Block was modified and has PO. Add it to the work list. + if (block->has_post_order() && + !block->is_on_work_list()) { add_to_work_list(block); } } @@ -2091,8 +2107,9 @@ for (int i = 0; i < len; i++) { Block* block = successors->at(i); if (block->meet(state)) { - // Block was modified. Add it to the work list. - if (!block->is_on_work_list()) { + // Block was modified and has PO. Add it to the work list. + if (block->has_post_order() && + !block->is_on_work_list()) { add_to_work_list(block); } } @@ -2133,6 +2150,111 @@ return true; } +// ------------------------------------------------------------------ +// ciTypeFlow::clone_loop_heads +// +// Clone the loop heads +bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) { + bool rslt = false; + for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) { + lp = iter.current(); + Block* head = lp->head(); + if (lp == loop_tree_root() || + lp->is_irreducible() || + !head->is_clonable_exit(lp)) + continue; + + // check not already cloned + if (head->backedge_copy_count() != 0) + continue; + + // check _no_ shared head below us + Loop* ch; + for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling()); + if (ch != NULL) + continue; + + // Clone head + Block* new_head = head->looping_succ(lp); + Block* clone = clone_loop_head(lp, temp_vector, temp_set); + // Update lp's info + clone->set_loop(lp); + lp->set_head(new_head); + lp->set_tail(clone); + // And move original head into outer loop + head->set_loop(lp->parent()); + + rslt = true; + } + return rslt; +} + +// ------------------------------------------------------------------ +// ciTypeFlow::clone_loop_head +// +// Clone lp's head and replace tail's successors with clone. +// +// | +// v +// head <-> body +// | +// v +// exit +// +// new_head +// +// | +// v +// head ----------\ +// | | +// | v +// | clone <-> body +// | | +// | /--/ +// | | +// v v +// exit +// +ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) { + Block* head = lp->head(); + Block* tail = lp->tail(); + if (CITraceTypeFlow) { + tty->print(">> Requesting clone of loop head "); head->print_value_on(tty); + tty->print(" for predecessor "); tail->print_value_on(tty); + tty->cr(); + } + Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy); + assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges"); + + assert(!clone->has_pre_order(), "just created"); + clone->set_next_pre_order(); + + // Insert clone after (orig) tail in reverse post order + clone->set_rpo_next(tail->rpo_next()); + tail->set_rpo_next(clone); + + // tail->head becomes tail->clone + for (SuccIter iter(tail); !iter.done(); iter.next()) { + if (iter.succ() == head) { + iter.set_succ(clone); + break; + } + } + flow_block(tail, temp_vector, temp_set); + if (head == tail) { + // For self-loops, clone->head becomes clone->clone + flow_block(clone, temp_vector, temp_set); + for (SuccIter iter(clone); !iter.done(); iter.next()) { + if (iter.succ() == head) { + iter.set_succ(clone); + break; + } + } + } + flow_block(clone, temp_vector, temp_set); + + return clone; +} // ------------------------------------------------------------------ // ciTypeFlow::flow_block @@ -2159,11 +2281,14 @@ // Grab the state from the current block. block->copy_state_into(state); + state->def_locals()->clear(); GrowableArray* exceptions = block->exceptions(); GrowableArray* exc_klasses = block->exc_klasses(); bool has_exceptions = exceptions->length() > 0; + bool exceptions_used = false; + ciBytecodeStream str(method()); str.reset_to_bci(start); Bytecodes::Code code; @@ -2172,6 +2297,7 @@ // Check for exceptional control flow from this point. if (has_exceptions && can_trap(str)) { flow_exceptions(exceptions, exc_klasses, state); + exceptions_used = true; } // Apply the effects of the current bytecode to our state. bool res = state->apply_one_bytecode(&str); @@ -2189,9 +2315,14 @@ block->print_on(tty); } + // Save set of locals defined in this block + block->def_locals()->add(state->def_locals()); + // Record (no) successors. block->successors(&str, state, jsrs); + assert(!has_exceptions || exceptions_used, "Not removing exceptions"); + // Discontinue interpretation of this Block. return; } @@ -2202,6 +2333,7 @@ // Check for exceptional control flow from this point. if (has_exceptions && can_trap(str)) { flow_exceptions(exceptions, exc_klasses, state); + exceptions_used = true; } // Fix the JsrSet to reflect effect of the bytecode. @@ -2218,11 +2350,306 @@ successors = block->successors(&str, NULL, NULL); } + // Save set of locals defined in this block + block->def_locals()->add(state->def_locals()); + + // Remove untaken exception paths + if (!exceptions_used) + exceptions->clear(); + // Pass our state to successors. flow_successors(successors, state); } // ------------------------------------------------------------------ +// ciTypeFlow::PostOrderLoops::next +// +// Advance to next loop tree using a postorder, left-to-right traversal. +void ciTypeFlow::PostorderLoops::next() { + assert(!done(), "must not be done."); + if (_current->sibling() != NULL) { + _current = _current->sibling(); + while (_current->child() != NULL) { + _current = _current->child(); + } + } else { + _current = _current->parent(); + } +} + +// ------------------------------------------------------------------ +// ciTypeFlow::PreOrderLoops::next +// +// Advance to next loop tree using a preorder, left-to-right traversal. +void ciTypeFlow::PreorderLoops::next() { + assert(!done(), "must not be done."); + if (_current->child() != NULL) { + _current = _current->child(); + } else if (_current->sibling() != NULL) { + _current = _current->sibling(); + } else { + while (_current != _root && _current->sibling() == NULL) { + _current = _current->parent(); + } + if (_current == _root) { + _current = NULL; + assert(done(), "must be done."); + } else { + assert(_current->sibling() != NULL, "must be more to do"); + _current = _current->sibling(); + } + } +} + +// ------------------------------------------------------------------ +// ciTypeFlow::Loop::sorted_merge +// +// Merge the branch lp into this branch, sorting on the loop head +// pre_orders. Returns the leaf of the merged branch. +// Child and sibling pointers will be setup later. +// Sort is (looking from leaf towards the root) +// descending on primary key: loop head's pre_order, and +// ascending on secondary key: loop tail's pre_order. +ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) { + Loop* leaf = this; + Loop* prev = NULL; + Loop* current = leaf; + while (lp != NULL) { + int lp_pre_order = lp->head()->pre_order(); + // Find insertion point for "lp" + while (current != NULL) { + if (current == lp) + return leaf; // Already in list + if (current->head()->pre_order() < lp_pre_order) + break; + if (current->head()->pre_order() == lp_pre_order && + current->tail()->pre_order() > lp->tail()->pre_order()) { + break; + } + prev = current; + current = current->parent(); + } + Loop* next_lp = lp->parent(); // Save future list of items to insert + // Insert lp before current + lp->set_parent(current); + if (prev != NULL) { + prev->set_parent(lp); + } else { + leaf = lp; + } + prev = lp; // Inserted item is new prev[ious] + lp = next_lp; // Next item to insert + } + return leaf; +} + +// ------------------------------------------------------------------ +// ciTypeFlow::build_loop_tree +// +// Incrementally build loop tree. +void ciTypeFlow::build_loop_tree(Block* blk) { + assert(!blk->is_post_visited(), "precondition"); + Loop* innermost = NULL; // merge of loop tree branches over all successors + + for (SuccIter iter(blk); !iter.done(); iter.next()) { + Loop* lp = NULL; + Block* succ = iter.succ(); + if (!succ->is_post_visited()) { + // Found backedge since predecessor post visited, but successor is not + assert(succ->pre_order() <= blk->pre_order(), "should be backedge"); + + // Create a LoopNode to mark this loop. + lp = new (arena()) Loop(succ, blk); + if (succ->loop() == NULL) + succ->set_loop(lp); + // succ->loop will be updated to innermost loop on a later call, when blk==succ + + } else { // Nested loop + lp = succ->loop(); + + // If succ is loop head, find outer loop. + while (lp != NULL && lp->head() == succ) { + lp = lp->parent(); + } + if (lp == NULL) { + // Infinite loop, it's parent is the root + lp = loop_tree_root(); + } + } + + // Check for irreducible loop. + // Successor has already been visited. If the successor's loop head + // has already been post-visited, then this is another entry into the loop. + while (lp->head()->is_post_visited() && lp != loop_tree_root()) { + _has_irreducible_entry = true; + lp->set_irreducible(succ); + if (!succ->is_on_work_list()) { + // Assume irreducible entries need more data flow + add_to_work_list(succ); + } + lp = lp->parent(); + assert(lp != NULL, "nested loop must have parent by now"); + } + + // Merge loop tree branch for all successors. + innermost = innermost == NULL ? lp : innermost->sorted_merge(lp); + + } // end loop + + if (innermost == NULL) { + assert(blk->successors()->length() == 0, "CFG exit"); + blk->set_loop(loop_tree_root()); + } else if (innermost->head() == blk) { + // If loop header, complete the tree pointers + if (blk->loop() != innermost) { +#if ASSERT + assert(blk->loop()->head() == innermost->head(), "same head"); + Loop* dl; + for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent()); + assert(dl == blk->loop(), "blk->loop() already in innermost list"); +#endif + blk->set_loop(innermost); + } + innermost->def_locals()->add(blk->def_locals()); + Loop* l = innermost; + Loop* p = l->parent(); + while (p && l->head() == blk) { + l->set_sibling(p->child()); // Put self on parents 'next child' + p->set_child(l); // Make self the first child of parent + p->def_locals()->add(l->def_locals()); + l = p; // Walk up the parent chain + p = l->parent(); + } + } else { + blk->set_loop(innermost); + innermost->def_locals()->add(blk->def_locals()); + } +} + +// ------------------------------------------------------------------ +// ciTypeFlow::Loop::contains +// +// Returns true if lp is nested loop. +bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const { + assert(lp != NULL, ""); + if (this == lp || head() == lp->head()) return true; + int depth1 = depth(); + int depth2 = lp->depth(); + if (depth1 > depth2) + return false; + while (depth1 < depth2) { + depth2--; + lp = lp->parent(); + } + return this == lp; +} + +// ------------------------------------------------------------------ +// ciTypeFlow::Loop::depth +// +// Loop depth +int ciTypeFlow::Loop::depth() const { + int dp = 0; + for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent()) + dp++; + return dp; +} + +#ifndef PRODUCT +// ------------------------------------------------------------------ +// ciTypeFlow::Loop::print +void ciTypeFlow::Loop::print(outputStream* st, int indent) const { + for (int i = 0; i < indent; i++) st->print(" "); + st->print("%d<-%d %s", + is_root() ? 0 : this->head()->pre_order(), + is_root() ? 0 : this->tail()->pre_order(), + is_irreducible()?" irr":""); + st->print(" defs: "); + def_locals()->print_on(st, _head->outer()->method()->max_locals()); + st->cr(); + for (Loop* ch = child(); ch != NULL; ch = ch->sibling()) + ch->print(st, indent+2); +} +#endif + +// ------------------------------------------------------------------ +// ciTypeFlow::df_flow_types +// +// Perform the depth first type flow analysis. Helper for flow_types. +void ciTypeFlow::df_flow_types(Block* start, + bool do_flow, + StateVector* temp_vector, + JsrSet* temp_set) { + int dft_len = 100; + GrowableArray stk(arena(), dft_len, 0, NULL); + + ciBlock* dummy = _methodBlocks->make_dummy_block(); + JsrSet* root_set = new JsrSet(NULL, 0); + Block* root_head = new (arena()) Block(this, dummy, root_set); + Block* root_tail = new (arena()) Block(this, dummy, root_set); + root_head->set_pre_order(0); + root_head->set_post_order(0); + root_tail->set_pre_order(max_jint); + root_tail->set_post_order(max_jint); + set_loop_tree_root(new (arena()) Loop(root_head, root_tail)); + + stk.push(start); + + _next_pre_order = 0; // initialize pre_order counter + _rpo_list = NULL; + int next_po = 0; // initialize post_order counter + + // Compute RPO and the control flow graph + int size; + while ((size = stk.length()) > 0) { + Block* blk = stk.top(); // Leave node on stack + if (!blk->is_visited()) { + // forward arc in graph + assert (!blk->has_pre_order(), ""); + blk->set_next_pre_order(); + + if (_next_pre_order >= MaxNodeLimit / 2) { + // Too many basic blocks. Bail out. + // This can happen when try/finally constructs are nested to depth N, + // and there is O(2**N) cloning of jsr bodies. See bug 4697245! + // "MaxNodeLimit / 2" is used because probably the parser will + // generate at least twice that many nodes and bail out. + record_failure("too many basic blocks"); + return; + } + if (do_flow) { + flow_block(blk, temp_vector, temp_set); + if (failing()) return; // Watch for bailouts. + } + } else if (!blk->is_post_visited()) { + // cross or back arc + for (SuccIter iter(blk); !iter.done(); iter.next()) { + Block* succ = iter.succ(); + if (!succ->is_visited()) { + stk.push(succ); + } + } + if (stk.length() == size) { + // There were no additional children, post visit node now + stk.pop(); // Remove node from stack + + build_loop_tree(blk); + blk->set_post_order(next_po++); // Assign post order + prepend_to_rpo_list(blk); + assert(blk->is_post_visited(), ""); + + if (blk->is_loop_head() && !blk->is_on_work_list()) { + // Assume loop heads need more data flow + add_to_work_list(blk); + } + } + } else { + stk.pop(); // Remove post-visited node from stack + } + } +} + +// ------------------------------------------------------------------ // ciTypeFlow::flow_types // // Perform the type flow analysis, creating and cloning Blocks as @@ -2233,91 +2660,93 @@ JsrSet* temp_set = new JsrSet(NULL, 16); // Create the method entry block. - Block* block = block_at(start_bci(), temp_set); - block->set_pre_order(_next_pre_order++); - assert(block->is_start(), "start block must have order #0"); + Block* start = block_at(start_bci(), temp_set); // Load the initial state into it. const StateVector* start_state = get_start_state(); if (failing()) return; - block->meet(start_state); - add_to_work_list(block); + start->meet(start_state); + + // Depth first visit + df_flow_types(start, true /*do flow*/, temp_vector, temp_set); - // Trickle away. - while (!work_list_empty()) { - Block* block = work_list_next(); - flow_block(block, temp_vector, temp_set); + if (failing()) return; + assert(_rpo_list == start, "must be start"); + // Any loops found? + if (loop_tree_root()->child() != NULL && + env()->comp_level() >= CompLevel_full_optimization) { + // Loop optimizations are not performed on Tier1 compiles. + + bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set); - // NodeCountCutoff is the number of nodes at which the parser - // will bail out. Probably if we already have lots of BBs, - // the parser will generate at least twice that many nodes and bail out. - // Therefore, this is a conservatively large limit at which to - // bail out in the pre-parse typeflow pass. - int block_limit = MaxNodeLimit / 2; + // If some loop heads were cloned, recompute postorder and loop tree + if (changed) { + loop_tree_root()->set_child(NULL); + for (Block* blk = _rpo_list; blk != NULL;) { + Block* next = blk->rpo_next(); + blk->df_init(); + blk = next; + } + df_flow_types(start, false /*no flow*/, temp_vector, temp_set); + } + } - if (_next_pre_order >= block_limit) { - // Too many basic blocks. Bail out. - // - // This can happen when try/finally constructs are nested to depth N, - // and there is O(2**N) cloning of jsr bodies. See bug 4697245! - record_failure("too many basic blocks"); - return; - } + if (CITraceTypeFlow) { + tty->print_cr("\nLoop tree"); + loop_tree_root()->print(); + } + + // Continue flow analysis until fixed point reached + + debug_only(int max_block = _next_pre_order;) - // Watch for bailouts. - if (failing()) return; + while (!work_list_empty()) { + Block* blk = work_list_next(); + assert (blk->has_post_order(), "post order assigned above"); + + flow_block(blk, temp_vector, temp_set); + + assert (max_block == _next_pre_order, "no new blocks"); + assert (!failing(), "no more bailouts"); } } // ------------------------------------------------------------------ // ciTypeFlow::map_blocks // -// Create the block map, which indexes blocks in pre_order. +// Create the block map, which indexes blocks in reverse post-order. void ciTypeFlow::map_blocks() { assert(_block_map == NULL, "single initialization"); - int pre_order_limit = _next_pre_order; - _block_map = NEW_ARENA_ARRAY(arena(), Block*, pre_order_limit); - assert(pre_order_limit == block_count(), ""); - int po; - for (po = 0; po < pre_order_limit; po++) { - debug_only(_block_map[po] = NULL); + int block_ct = _next_pre_order; + _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct); + assert(block_ct == block_count(), ""); + + Block* blk = _rpo_list; + for (int m = 0; m < block_ct; m++) { + int rpo = blk->rpo(); + assert(rpo == m, "should be sequential"); + _block_map[rpo] = blk; + blk = blk->rpo_next(); } - ciMethodBlocks *mblks = _methodBlocks; - ciBlock* current = NULL; - int limit_bci = code_size(); - for (int bci = 0; bci < limit_bci; bci++) { - ciBlock* ciblk = mblks->block_containing(bci); - if (ciblk != NULL && ciblk != current) { - current = ciblk; - int curidx = ciblk->index(); - int block_count = (_idx_to_blocklist[curidx] == NULL) ? 0 : _idx_to_blocklist[curidx]->length(); - for (int i = 0; i < block_count; i++) { - Block* block = _idx_to_blocklist[curidx]->at(i); - if (!block->has_pre_order()) continue; - int po = block->pre_order(); - assert(_block_map[po] == NULL, "unique ref to block"); - assert(0 <= po && po < pre_order_limit, ""); - _block_map[po] = block; - } - } - } - for (po = 0; po < pre_order_limit; po++) { - assert(_block_map[po] != NULL, "must not drop any blocks"); - Block* block = _block_map[po]; + assert(blk == NULL, "should be done"); + + for (int j = 0; j < block_ct; j++) { + assert(_block_map[j] != NULL, "must not drop any blocks"); + Block* block = _block_map[j]; // Remove dead blocks from successor lists: for (int e = 0; e <= 1; e++) { GrowableArray* l = e? block->exceptions(): block->successors(); - for (int i = 0; i < l->length(); i++) { - Block* s = l->at(i); - if (!s->has_pre_order()) { + for (int k = 0; k < l->length(); k++) { + Block* s = l->at(k); + if (!s->has_post_order()) { if (CITraceTypeFlow) { tty->print("Removing dead %s successor of #%d: ", (e? "exceptional": "normal"), block->pre_order()); s->print_value_on(tty); tty->cr(); } l->remove(s); - --i; + --k; } } } @@ -2329,7 +2758,7 @@ // // Find a block with this ciBlock which has a compatible JsrSet. // If no such block exists, create it, unless the option is no_create. -// If the option is create_private_copy, always create a fresh private copy. +// If the option is create_backedge_copy, always create a fresh backedge copy. ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) { Arena* a = arena(); GrowableArray* blocks = _idx_to_blocklist[ciBlockIndex]; @@ -2342,11 +2771,11 @@ _idx_to_blocklist[ciBlockIndex] = blocks; } - if (option != create_private_copy) { + if (option != create_backedge_copy) { int len = blocks->length(); for (int i = 0; i < len; i++) { Block* block = blocks->at(i); - if (!block->is_private_copy() && block->is_compatible_with(jsrs)) { + if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) { return block; } } @@ -2357,15 +2786,15 @@ // We did not find a compatible block. Create one. Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs); - if (option == create_private_copy) new_block->set_private_copy(true); + if (option == create_backedge_copy) new_block->set_backedge_copy(true); blocks->append(new_block); return new_block; } // ------------------------------------------------------------------ -// ciTypeFlow::private_copy_count +// ciTypeFlow::backedge_copy_count // -int ciTypeFlow::private_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const { +int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const { GrowableArray* blocks = _idx_to_blocklist[ciBlockIndex]; if (blocks == NULL) { @@ -2376,7 +2805,7 @@ int len = blocks->length(); for (int i = 0; i < len; i++) { Block* block = blocks->at(i); - if (block->is_private_copy() && block->is_compatible_with(jsrs)) { + if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) { count++; } } @@ -2405,10 +2834,12 @@ if (failing()) { return; } + + map_blocks(); + if (CIPrintTypeFlow || CITraceTypeFlow) { - print_on(tty); + rpo_print_on(tty); } - map_blocks(); } // ------------------------------------------------------------------ @@ -2466,4 +2897,19 @@ st->print_cr("********************************************************"); st->cr(); } + +void ciTypeFlow::rpo_print_on(outputStream* st) const { + st->print_cr("********************************************************"); + st->print ("TypeFlow for "); + method()->name()->print_symbol_on(st); + int limit_bci = code_size(); + st->print_cr(" %d bytes", limit_bci); + for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) { + blk->print_on(st); + st->print_cr("--------------------------------------------------------"); + st->cr(); + } + st->print_cr("********************************************************"); + st->cr(); +} #endif diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/ci/ciTypeFlow.hpp --- a/src/share/vm/ci/ciTypeFlow.hpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/ci/ciTypeFlow.hpp Wed Sep 17 12:59:52 2008 -0700 @@ -34,11 +34,13 @@ int _max_locals; int _max_stack; int _code_size; + bool _has_irreducible_entry; const char* _failure_reason; public: class StateVector; + class Loop; class Block; // Build a type flow analyzer @@ -55,6 +57,7 @@ int max_stack() const { return _max_stack; } int max_cells() const { return _max_locals + _max_stack; } int code_size() const { return _code_size; } + bool has_irreducible_entry() const { return _has_irreducible_entry; } // Represents information about an "active" jsr call. This // class represents a call to the routine at some entry address @@ -125,6 +128,19 @@ void print_on(outputStream* st) const PRODUCT_RETURN; }; + class LocalSet VALUE_OBJ_CLASS_SPEC { + private: + enum Constants { max = 63 }; + uint64_t _bits; + public: + LocalSet() : _bits(0) {} + void add(uint32_t i) { if (i < (uint32_t)max) _bits |= (1LL << i); } + void add(LocalSet* ls) { _bits |= ls->_bits; } + bool test(uint32_t i) const { return i < (uint32_t)max ? (_bits>>i)&1U : true; } + void clear() { _bits = 0; } + void print_on(outputStream* st, int limit) const PRODUCT_RETURN; + }; + // Used as a combined index for locals and temps enum Cell { Cell_0, Cell_max = INT_MAX @@ -142,6 +158,8 @@ int _trap_bci; int _trap_index; + LocalSet _def_locals; // For entire block + static ciType* type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer); public: @@ -181,6 +199,9 @@ int monitor_count() const { return _monitor_count; } void set_monitor_count(int mc) { _monitor_count = mc; } + LocalSet* def_locals() { return &_def_locals; } + const LocalSet* def_locals() const { return &_def_locals; } + static Cell start_cell() { return (Cell)0; } static Cell next_cell(Cell c) { return (Cell)(((int)c) + 1); } Cell limit_cell() const { @@ -250,6 +271,10 @@ return type->basic_type() == T_DOUBLE; } + void store_to_local(int lnum) { + _def_locals.add((uint) lnum); + } + void push_translate(ciType* type); void push_int() { @@ -358,6 +383,7 @@ "must be reference type or return address"); overwrite_local_double_long(index); set_type_at(local(index), type); + store_to_local(index); } void load_local_double(int index) { @@ -376,6 +402,8 @@ overwrite_local_double_long(index); set_type_at(local(index), type); set_type_at(local(index+1), type2); + store_to_local(index); + store_to_local(index+1); } void load_local_float(int index) { @@ -388,6 +416,7 @@ assert(is_float(type), "must be float type"); overwrite_local_double_long(index); set_type_at(local(index), type); + store_to_local(index); } void load_local_int(int index) { @@ -400,6 +429,7 @@ assert(is_int(type), "must be int type"); overwrite_local_double_long(index); set_type_at(local(index), type); + store_to_local(index); } void load_local_long(int index) { @@ -418,6 +448,8 @@ overwrite_local_double_long(index); set_type_at(local(index), type); set_type_at(local(index+1), type2); + store_to_local(index); + store_to_local(index+1); } // Stop interpretation of this path with a trap. @@ -450,13 +482,31 @@ }; // Parameter for "find_block" calls: - // Describes the difference between a public and private copy. + // Describes the difference between a public and backedge copy. enum CreateOption { create_public_copy, - create_private_copy, + create_backedge_copy, no_create }; + // Successor iterator + class SuccIter : public StackObj { + private: + Block* _pred; + int _index; + Block* _succ; + public: + SuccIter() : _pred(NULL), _index(-1), _succ(NULL) {} + SuccIter(Block* pred) : _pred(pred), _index(-1), _succ(NULL) { next(); } + int index() { return _index; } + Block* pred() { return _pred; } // Return predecessor + bool done() { return _index < 0; } // Finished? + Block* succ() { return _succ; } // Return current successor + void next(); // Advance + void set_succ(Block* succ); // Update current successor + bool is_normal_ctrl() { return index() < _pred->successors()->length(); } + }; + // A basic block class Block : public ResourceObj { private: @@ -470,15 +520,24 @@ int _trap_bci; int _trap_index; - // A reasonable approximation to pre-order, provided.to the client. + // pre_order, assigned at first visit. Used as block ID and "visited" tag int _pre_order; - // Has this block been cloned for some special purpose? - bool _private_copy; + // A post-order, used to compute the reverse post order (RPO) provided to the client + int _post_order; // used to compute rpo + + // Has this block been cloned for a loop backedge? + bool _backedge_copy; // A pointer used for our internal work list - Block* _next; - bool _on_work_list; + Block* _next; + bool _on_work_list; // on the work list + Block* _rpo_next; // Reverse post order list + + // Loop info + Loop* _loop; // nearest loop + bool _irreducible_entry; // entry to irreducible loop + bool _exception_entry; // entry to exception handler ciBlock* ciblock() const { return _ciblock; } StateVector* state() const { return _state; } @@ -504,10 +563,11 @@ int start() const { return _ciblock->start_bci(); } int limit() const { return _ciblock->limit_bci(); } int control() const { return _ciblock->control_bci(); } + JsrSet* jsrs() const { return _jsrs; } - bool is_private_copy() const { return _private_copy; } - void set_private_copy(bool z); - int private_copy_count() const { return outer()->private_copy_count(ciblock()->index(), _jsrs); } + bool is_backedge_copy() const { return _backedge_copy; } + void set_backedge_copy(bool z); + int backedge_copy_count() const { return outer()->backedge_copy_count(ciblock()->index(), _jsrs); } // access to entry state int stack_size() const { return _state->stack_size(); } @@ -515,6 +575,20 @@ ciType* local_type_at(int i) const { return _state->local_type_at(i); } ciType* stack_type_at(int i) const { return _state->stack_type_at(i); } + // Data flow on locals + bool is_invariant_local(uint v) const { + assert(is_loop_head(), "only loop heads"); + // Find outermost loop with same loop head + Loop* lp = loop(); + while (lp->parent() != NULL) { + if (lp->parent()->head() != lp->head()) break; + lp = lp->parent(); + } + return !lp->def_locals()->test(v); + } + LocalSet* def_locals() { return _state->def_locals(); } + const LocalSet* def_locals() const { return _state->def_locals(); } + // Get the successors for this Block. GrowableArray* successors(ciBytecodeStream* str, StateVector* state, @@ -524,13 +598,6 @@ return _successors; } - // Helper function for "successors" when making private copies of - // loop heads for C2. - Block * clone_loop_head(ciTypeFlow* analyzer, - int branch_bci, - Block* target, - JsrSet* jsrs); - // Get the exceptional successors for this Block. GrowableArray* exceptions() { if (_exceptions == NULL) { @@ -584,17 +651,126 @@ bool is_on_work_list() const { return _on_work_list; } bool has_pre_order() const { return _pre_order >= 0; } - void set_pre_order(int po) { assert(!has_pre_order() && po >= 0, ""); _pre_order = po; } + void set_pre_order(int po) { assert(!has_pre_order(), ""); _pre_order = po; } int pre_order() const { assert(has_pre_order(), ""); return _pre_order; } + void set_next_pre_order() { set_pre_order(outer()->inc_next_pre_order()); } bool is_start() const { return _pre_order == outer()->start_block_num(); } - // A ranking used in determining order within the work list. - bool is_simpler_than(Block* other); + // Reverse post order + void df_init(); + bool has_post_order() const { return _post_order >= 0; } + void set_post_order(int po) { assert(!has_post_order() && po >= 0, ""); _post_order = po; } + void reset_post_order(int o){ _post_order = o; } + int post_order() const { assert(has_post_order(), ""); return _post_order; } + + bool has_rpo() const { return has_post_order() && outer()->have_block_count(); } + int rpo() const { assert(has_rpo(), ""); return outer()->block_count() - post_order() - 1; } + void set_rpo_next(Block* b) { _rpo_next = b; } + Block* rpo_next() { return _rpo_next; } + + // Loops + Loop* loop() const { return _loop; } + void set_loop(Loop* lp) { _loop = lp; } + bool is_loop_head() const { return _loop && _loop->head() == this; } + void set_irreducible_entry(bool c) { _irreducible_entry = c; } + bool is_irreducible_entry() const { return _irreducible_entry; } + bool is_visited() const { return has_pre_order(); } + bool is_post_visited() const { return has_post_order(); } + bool is_clonable_exit(Loop* lp); + Block* looping_succ(Loop* lp); // Successor inside of loop + bool is_single_entry_loop_head() const { + if (!is_loop_head()) return false; + for (Loop* lp = loop(); lp != NULL && lp->head() == this; lp = lp->parent()) + if (lp->is_irreducible()) return false; + return true; + } void print_value_on(outputStream* st) const PRODUCT_RETURN; void print_on(outputStream* st) const PRODUCT_RETURN; }; + // Loop + class Loop : public ResourceObj { + private: + Loop* _parent; + Loop* _sibling; // List of siblings, null terminated + Loop* _child; // Head of child list threaded thru sibling pointer + Block* _head; // Head of loop + Block* _tail; // Tail of loop + bool _irreducible; + LocalSet _def_locals; + + public: + Loop(Block* head, Block* tail) : + _head(head), _tail(tail), + _parent(NULL), _sibling(NULL), _child(NULL), + _irreducible(false), _def_locals() {} + + Loop* parent() const { return _parent; } + Loop* sibling() const { return _sibling; } + Loop* child() const { return _child; } + Block* head() const { return _head; } + Block* tail() const { return _tail; } + void set_parent(Loop* p) { _parent = p; } + void set_sibling(Loop* s) { _sibling = s; } + void set_child(Loop* c) { _child = c; } + void set_head(Block* hd) { _head = hd; } + void set_tail(Block* tl) { _tail = tl; } + + int depth() const; // nesting depth + + // Returns true if lp is a nested loop or us. + bool contains(Loop* lp) const; + bool contains(Block* blk) const { return contains(blk->loop()); } + + // Data flow on locals + LocalSet* def_locals() { return &_def_locals; } + const LocalSet* def_locals() const { return &_def_locals; } + + // Merge the branch lp into this branch, sorting on the loop head + // pre_orders. Returns the new branch. + Loop* sorted_merge(Loop* lp); + + // Mark non-single entry to loop + void set_irreducible(Block* entry) { + _irreducible = true; + entry->set_irreducible_entry(true); + } + bool is_irreducible() const { return _irreducible; } + + bool is_root() const { return _tail->pre_order() == max_jint; } + + void print(outputStream* st = tty, int indent = 0) const PRODUCT_RETURN; + }; + + // Postorder iteration over the loop tree. + class PostorderLoops : public StackObj { + private: + Loop* _root; + Loop* _current; + public: + PostorderLoops(Loop* root) : _root(root), _current(root) { + while (_current->child() != NULL) { + _current = _current->child(); + } + } + bool done() { return _current == NULL; } // Finished iterating? + void next(); // Advance to next loop + Loop* current() { return _current; } // Return current loop. + }; + + // Preorder iteration over the loop tree. + class PreorderLoops : public StackObj { + private: + Loop* _root; + Loop* _current; + public: + PreorderLoops(Loop* root) : _root(root), _current(root) {} + bool done() { return _current == NULL; } // Finished iterating? + void next(); // Advance to next loop + Loop* current() { return _current; } // Return current loop. + }; + // Standard indexes of successors, for various bytecodes. enum { FALL_THROUGH = 0, // normal control @@ -619,6 +795,12 @@ // Tells if a given instruction is able to generate an exception edge. bool can_trap(ciBytecodeStream& str); + // Clone the loop heads. Returns true if any cloning occurred. + bool clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set); + + // Clone lp's head and replace tail's successors with clone. + Block* clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set); + public: // Return the block beginning at bci which has a JsrSet compatible // with jsrs. @@ -627,8 +809,8 @@ // block factory Block* get_block_for(int ciBlockIndex, JsrSet* jsrs, CreateOption option = create_public_copy); - // How many of the blocks have the private_copy bit set? - int private_copy_count(int ciBlockIndex, JsrSet* jsrs) const; + // How many of the blocks have the backedge_copy bit set? + int backedge_copy_count(int ciBlockIndex, JsrSet* jsrs) const; // Return an existing block containing bci which has a JsrSet compatible // with jsrs, or NULL if there is none. @@ -651,11 +833,18 @@ return _block_map[po]; } Block* start_block() const { return pre_order_at(start_block_num()); } int start_block_num() const { return 0; } + Block* rpo_at(int rpo) const { assert(0 <= rpo && rpo < block_count(), "out of bounds"); + return _block_map[rpo]; } + int next_pre_order() { return _next_pre_order; } + int inc_next_pre_order() { return _next_pre_order++; } private: // A work list used during flow analysis. Block* _work_list; + // List of blocks in reverse post order + Block* _rpo_list; + // Next Block::_pre_order. After mapping, doubles as block_count. int _next_pre_order; @@ -668,6 +857,15 @@ // Add a basic block to our work list. void add_to_work_list(Block* block); + // Prepend a basic block to rpo list. + void prepend_to_rpo_list(Block* blk) { + blk->set_rpo_next(_rpo_list); + _rpo_list = blk; + } + + // Root of the loop tree + Loop* _loop_tree_root; + // State used for make_jsr_record int _jsr_count; GrowableArray* _jsr_records; @@ -677,6 +875,9 @@ // does not already exist. JsrRecord* make_jsr_record(int entry_address, int return_address); + void set_loop_tree_root(Loop* ltr) { _loop_tree_root = ltr; } + Loop* loop_tree_root() { return _loop_tree_root; } + private: // Get the initial state for start_bci: const StateVector* get_start_state(); @@ -703,6 +904,15 @@ // necessary. void flow_types(); + // Perform the depth first type flow analysis. Helper for flow_types. + void df_flow_types(Block* start, + bool do_flow, + StateVector* temp_vector, + JsrSet* temp_set); + + // Incrementally build loop tree. + void build_loop_tree(Block* blk); + // Create the block map, which indexes blocks in pre_order. void map_blocks(); @@ -711,4 +921,6 @@ void do_flow(); void print_on(outputStream* st) const PRODUCT_RETURN; + + void rpo_print_on(outputStream* st) const PRODUCT_RETURN; }; diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/includeDB_compiler2 --- a/src/share/vm/includeDB_compiler2 Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/includeDB_compiler2 Wed Sep 17 12:59:52 2008 -0700 @@ -582,6 +582,7 @@ loopTransform.cpp addnode.hpp loopTransform.cpp allocation.inline.hpp loopTransform.cpp connode.hpp +loopTransform.cpp compileLog.hpp loopTransform.cpp divnode.hpp loopTransform.cpp loopnode.hpp loopTransform.cpp mulnode.hpp @@ -597,6 +598,7 @@ loopnode.cpp allocation.inline.hpp loopnode.cpp callnode.hpp loopnode.cpp ciMethodData.hpp +loopnode.cpp compileLog.hpp loopnode.cpp connode.hpp loopnode.cpp divnode.hpp loopnode.cpp loopnode.hpp diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/bytecodeInfo.cpp --- a/src/share/vm/opto/bytecodeInfo.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/bytecodeInfo.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -25,19 +25,6 @@ #include "incls/_precompiled.incl" #include "incls/_bytecodeInfo.cpp.incl" -// These variables are declared in parse1.cpp -extern int explicit_null_checks_inserted; -extern int explicit_null_checks_elided; -extern int explicit_null_checks_inserted_old; -extern int explicit_null_checks_elided_old; -extern int nodes_created_old; -extern int nodes_created; -extern int methods_parsed_old; -extern int methods_parsed; -extern int methods_seen; -extern int methods_seen_old; - - //============================================================================= //------------------------------InlineTree------------------------------------- InlineTree::InlineTree( Compile* c, const InlineTree *caller_tree, ciMethod* callee, JVMState* caller_jvms, int caller_bci, float site_invoke_ratio ) @@ -517,27 +504,3 @@ } return iltp; } - -// ---------------------------------------------------------------------------- -#ifndef PRODUCT - -static void per_method_stats() { - // Compute difference between this method's cumulative totals and old totals - int explicit_null_checks_cur = explicit_null_checks_inserted - explicit_null_checks_inserted_old; - int elided_null_checks_cur = explicit_null_checks_elided - explicit_null_checks_elided_old; - - // Print differences - if( explicit_null_checks_cur ) - tty->print_cr("XXX Explicit NULL checks inserted: %d", explicit_null_checks_cur); - if( elided_null_checks_cur ) - tty->print_cr("XXX Explicit NULL checks removed at parse time: %d", elided_null_checks_cur); - - // Store the current cumulative totals - nodes_created_old = nodes_created; - methods_parsed_old = methods_parsed; - methods_seen_old = methods_seen; - explicit_null_checks_inserted_old = explicit_null_checks_inserted; - explicit_null_checks_elided_old = explicit_null_checks_elided; -} - -#endif diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/cfgnode.cpp --- a/src/share/vm/opto/cfgnode.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/cfgnode.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -1665,7 +1665,11 @@ // compress paths and change unreachable cycles to TOP // If not, we can update the input infinitely along a MergeMem cycle // Equivalent code is in MemNode::Ideal_common - Node *m = phase->transform(n); + Node *m = phase->transform(n); + if (outcnt() == 0) { // Above transform() may kill us! + progress = phase->C->top(); + break; + } // If tranformed to a MergeMem, get the desired slice // Otherwise the returned node represents memory for every slice Node *new_mem = (m->is_MergeMem()) ? diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/compile.cpp --- a/src/share/vm/opto/compile.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/compile.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -467,6 +467,7 @@ } } set_print_assembly(print_opto_assembly); + set_parsed_irreducible_loop(false); #endif if (ProfileTraps) { @@ -550,6 +551,8 @@ rethrow_exceptions(kit.transfer_exceptions_into_jvms()); } + print_method("Before RemoveUseless"); + // Remove clutter produced by parsing. if (!failing()) { ResourceMark rm; @@ -615,8 +618,6 @@ if (failing()) return; NOT_PRODUCT( verify_graph_edges(); ) - print_method("Before Matching"); - #ifndef PRODUCT if (PrintIdeal) { ttyLocker ttyl; // keep the following output all in one block @@ -720,6 +721,7 @@ TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false); TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false); set_print_assembly(PrintFrameConverterAssembly); + set_parsed_irreducible_loop(false); #endif CompileWrapper cw(this); Init(/*AliasLevel=*/ 0); diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/compile.hpp --- a/src/share/vm/opto/compile.hpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/compile.hpp Wed Sep 17 12:59:52 2008 -0700 @@ -160,6 +160,7 @@ bool _print_assembly; // True if we should dump assembly code for this compilation #ifndef PRODUCT bool _trace_opto_output; + bool _parsed_irreducible_loop; // True if ciTypeFlow detected irreducible loops during parsing #endif // Compilation environment. @@ -319,6 +320,8 @@ } #ifndef PRODUCT bool trace_opto_output() const { return _trace_opto_output; } + bool parsed_irreducible_loop() const { return _parsed_irreducible_loop; } + void set_parsed_irreducible_loop(bool z) { _parsed_irreducible_loop = z; } #endif void begin_method() { diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/doCall.cpp --- a/src/share/vm/opto/doCall.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/doCall.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -795,7 +795,7 @@ ciInstanceKlass *ikl = receiver_type->klass()->as_instance_klass(); if (ikl->is_loaded() && ikl->is_initialized() && !ikl->is_interface() && - (ikl == actual_receiver || ikl->is_subclass_of(actual_receiver))) { + (ikl == actual_receiver || ikl->is_subtype_of(actual_receiver))) { // ikl is a same or better type than the original actual_receiver, // e.g. static receiver from bytecodes. actual_receiver = ikl; diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/graphKit.cpp --- a/src/share/vm/opto/graphKit.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/graphKit.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -587,7 +587,7 @@ #ifdef ASSERT _bci = kit->bci(); Parse* parser = kit->is_Parse(); - int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->pre_order(); + int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo(); _block = block; #endif } @@ -596,7 +596,7 @@ #ifdef ASSERT assert(kit->bci() == _bci, "bci must not shift"); Parse* parser = kit->is_Parse(); - int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->pre_order(); + int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo(); assert(block == _block, "block must not shift"); #endif kit->set_map(_map); diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/loopTransform.cpp --- a/src/share/vm/opto/loopTransform.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/loopTransform.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -1012,6 +1012,8 @@ if (!has_ctrl(old)) set_loop(nnn, loop); } + + loop->record_for_igvn(); } //------------------------------do_maximally_unroll---------------------------- diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/loopnode.cpp --- a/src/share/vm/opto/loopnode.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/loopnode.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -1279,7 +1279,7 @@ // Visit all children, looking for Phis for (DUIterator i = cl->outs(); cl->has_out(i); i++) { Node *out = cl->out(i); - if (!out->is_Phi()) continue; // Looking for phis + if (!out->is_Phi() || out == phi) continue; // Looking for other phis PhiNode* phi2 = out->as_Phi(); Node *incr2 = phi2->in( LoopNode::LoopBackControl ); // Look for induction variables of the form: X += constant @@ -1388,6 +1388,37 @@ #endif +static void log_loop_tree(IdealLoopTree* root, IdealLoopTree* loop, CompileLog* log) { + if (loop == root) { + if (loop->_child != NULL) { + log->begin_head("loop_tree"); + log->end_head(); + if( loop->_child ) log_loop_tree(root, loop->_child, log); + log->tail("loop_tree"); + assert(loop->_next == NULL, "what?"); + } + } else { + Node* head = loop->_head; + log->begin_head("loop"); + log->print(" idx='%d' ", head->_idx); + if (loop->_irreducible) log->print("irreducible='1' "); + if (head->is_Loop()) { + if (head->as_Loop()->is_inner_loop()) log->print("inner_loop='1' "); + if (head->as_Loop()->is_partial_peel_loop()) log->print("partial_peel_loop='1' "); + } + if (head->is_CountedLoop()) { + CountedLoopNode* cl = head->as_CountedLoop(); + if (cl->is_pre_loop()) log->print("pre_loop='%d' ", cl->main_idx()); + if (cl->is_main_loop()) log->print("main_loop='%d' ", cl->_idx); + if (cl->is_post_loop()) log->print("post_loop='%d' ", cl->main_idx()); + } + log->end_head(); + if( loop->_child ) log_loop_tree(root, loop->_child, log); + log->tail("loop"); + if( loop->_next ) log_loop_tree(root, loop->_next, log); + } +} + //============================================================================= //------------------------------PhaseIdealLoop--------------------------------- // Create a PhaseLoop. Build the ideal Loop tree. Map each Ideal Node to @@ -1624,10 +1655,13 @@ // Cleanup any modified bits _igvn.optimize(); - // Do not repeat loop optimizations if irreducible loops are present - // by claiming no-progress. - if( _has_irreducible_loops ) - C->clear_major_progress(); + // disable assert until issue with split_flow_path is resolved (6742111) + // assert(!_has_irreducible_loops || C->parsed_irreducible_loop() || C->is_osr_compilation(), + // "shouldn't introduce irreducible loops"); + + if (C->log() != NULL) { + log_loop_tree(_ltree_root, _ltree_root, C->log()); + } } #ifndef PRODUCT @@ -2732,11 +2766,7 @@ } void PhaseIdealLoop::dump( IdealLoopTree *loop, uint idx, Node_List &rpo_list ) const { - - // Indent by loop nesting depth - for( uint x = 0; x < loop->_nest; x++ ) - tty->print(" "); - tty->print_cr("---- Loop N%d-N%d ----", loop->_head->_idx,loop->_tail->_idx); + loop->dump_head(); // Now scan for CFG nodes in the same loop for( uint j=idx; j > 0; j-- ) { diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/loopnode.hpp --- a/src/share/vm/opto/loopnode.hpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/loopnode.hpp Wed Sep 17 12:59:52 2008 -0700 @@ -192,6 +192,8 @@ int is_main_no_pre_loop() const { return _loop_flags & Main_Has_No_Pre_Loop; } void set_main_no_pre_loop() { _loop_flags |= Main_Has_No_Pre_Loop; } + int main_idx() const { return _main_idx; } + void set_pre_loop (CountedLoopNode *main) { assert(is_normal_loop(),""); _loop_flags |= Pre ; _main_idx = main->_idx; } void set_main_loop ( ) { assert(is_normal_loop(),""); _loop_flags |= Main; } diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/loopopts.cpp --- a/src/share/vm/opto/loopopts.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/loopopts.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -2667,6 +2667,10 @@ // Fix this by adjusting to use the post-increment trip counter. Node *phi = cl->phi(); if( !phi ) return; // Dead infinite loop + + // Shape messed up, probably by iteration_split_impl + if (phi->in(LoopNode::LoopBackControl) != cl->incr()) return; + bool progress = true; while (progress) { progress = false; diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/matcher.cpp --- a/src/share/vm/opto/matcher.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/matcher.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -273,7 +273,7 @@ find_shared( C->root() ); find_shared( C->top() ); - C->print_method("Before Matching", 2); + C->print_method("Before Matching"); // Swap out to old-space; emptying new-space Arena *old = C->node_arena()->move_contents(C->old_arena()); diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/parse.hpp --- a/src/share/vm/opto/parse.hpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/parse.hpp Wed Sep 17 12:59:52 2008 -0700 @@ -167,9 +167,19 @@ int start() const { return flow()->start(); } int limit() const { return flow()->limit(); } - int pre_order() const { return flow()->pre_order(); } + int rpo() const { return flow()->rpo(); } int start_sp() const { return flow()->stack_size(); } + bool is_loop_head() const { return flow()->is_loop_head(); } + bool is_SEL_head() const { return flow()->is_single_entry_loop_head(); } + bool is_SEL_backedge(Block* pred) const{ return is_SEL_head() && pred->rpo() >= rpo(); } + bool is_invariant_local(uint i) const { + const JVMState* jvms = start_map()->jvms(); + if (!jvms->is_loc(i)) return false; + return flow()->is_invariant_local(i - jvms->locoff()); + } + bool can_elide_SEL_phi(uint i) const { assert(is_SEL_head(),""); return is_invariant_local(i); } + const Type* peek(int off=0) const { return stack_type_at(start_sp() - (off+1)); } const Type* stack_type_at(int i) const; @@ -305,7 +315,7 @@ // entry_bci() -- see osr_bci, etc. ciTypeFlow* flow() const { return _flow; } - // blocks() -- see pre_order_at, start_block, etc. + // blocks() -- see rpo_at, start_block, etc. int block_count() const { return _block_count; } GraphKit& exits() { return _exits; } @@ -330,12 +340,12 @@ // Must this parse be aborted? bool failing() { return C->failing(); } - Block* pre_order_at(int po) { - assert(0 <= po && po < _block_count, "oob"); - return &_blocks[po]; + Block* rpo_at(int rpo) { + assert(0 <= rpo && rpo < _block_count, "oob"); + return &_blocks[rpo]; } Block* start_block() { - return pre_order_at(flow()->start_block()->pre_order()); + return rpo_at(flow()->start_block()->rpo()); } // Can return NULL if the flow pass did not complete a block. Block* successor_for_bci(int bci) { @@ -359,9 +369,6 @@ // Parse all the basic blocks. void do_all_blocks(); - // Helper for do_all_blocks; makes one pass in pre-order. - void visit_blocks(); - // Parse the current basic block void do_one_block(); diff -r 8261ee795323 -r 194b8e3a2fc4 src/share/vm/opto/parse1.cpp --- a/src/share/vm/opto/parse1.cpp Wed Sep 17 08:29:17 2008 -0700 +++ b/src/share/vm/opto/parse1.cpp Wed Sep 17 12:59:52 2008 -0700 @@ -29,17 +29,17 @@ // the most. Some of the non-static variables are needed in bytecodeInfo.cpp // and eventually should be encapsulated in a proper class (gri 8/18/98). -int nodes_created = 0; int nodes_created_old = 0; -int methods_parsed = 0; int methods_parsed_old = 0; -int methods_seen = 0; int methods_seen_old = 0; +int nodes_created = 0; +int methods_parsed = 0; +int methods_seen = 0; +int blocks_parsed = 0; +int blocks_seen = 0; -int explicit_null_checks_inserted = 0, explicit_null_checks_inserted_old = 0; -int explicit_null_checks_elided = 0, explicit_null_checks_elided_old = 0; +int explicit_null_checks_inserted = 0; +int explicit_null_checks_elided = 0; int all_null_checks_found = 0, implicit_null_checks = 0; int implicit_null_throws = 0; -int parse_idx = 0; -size_t parse_arena = 0; int reclaim_idx = 0; int reclaim_in = 0; int reclaim_node = 0; @@ -61,6 +61,7 @@ tty->cr(); if (methods_seen != methods_parsed) tty->print_cr("Reasons for parse failures (NOT cumulative):"); + tty->print_cr("Blocks parsed: %d Blocks seen: %d", blocks_parsed, blocks_seen); if( explicit_null_checks_inserted ) tty->print_cr("%d original NULL checks - %d elided (%2d%%); optimizer leaves %d,", explicit_null_checks_inserted, explicit_null_checks_elided, (100*explicit_null_checks_elided)/explicit_null_checks_inserted, all_null_checks_found); @@ -373,6 +374,12 @@ C->record_method_not_compilable_all_tiers(_flow->failure_reason()); } +#ifndef PRODUCT + if (_flow->has_irreducible_entry()) { + C->set_parsed_irreducible_loop(true); + } +#endif + if (_expected_uses <= 0) { _prof_factor = 1; } else { @@ -556,118 +563,93 @@ set_map(entry_map); do_exits(); - // Collect a few more statistics. - parse_idx += C->unique(); - parse_arena += C->node_arena()->used(); - if (log) log->done("parse nodes='%d' memory='%d'", C->unique(), C->node_arena()->used()); } //---------------------------do_all_blocks------------------------------------- void Parse::do_all_blocks() { - _blocks_merged = 0; - _blocks_parsed = 0; + bool has_irreducible = flow()->has_irreducible_entry(); + + // Walk over all blocks in Reverse Post-Order. + while (true) { + bool progress = false; + for (int rpo = 0; rpo < block_count(); rpo++) { + Block* block = rpo_at(rpo); + + if (block->is_parsed()) continue; - int old_blocks_merged = -1; - int old_blocks_parsed = -1; + if (!block->is_merged()) { + // Dead block, no state reaches this block + continue; + } - for (int tries = 0; ; tries++) { - visit_blocks(); - if (failing()) return; // Check for bailout + // Prepare to parse this block. + load_state_from(block); + + if (stopped()) { + // Block is dead. + continue; + } + + blocks_parsed++; - // No need for a work list. The outer loop is hardly ever repeated. - // The following loop traverses the blocks in a reasonable pre-order, - // as produced by the ciTypeFlow pass. + progress = true; + if (block->is_loop_head() || block->is_handler() || has_irreducible && !block->is_ready()) { + // Not all preds have been parsed. We must build phis everywhere. + // (Note that dead locals do not get phis built, ever.) + ensure_phis_everywhere(); + + // Leave behind an undisturbed copy of the map, for future merges. + set_map(clone_map()); + } - // This loop can be taken more than once if there are two entries to - // a loop (irreduceable CFG), and the edge which ciTypeFlow chose - // as the first predecessor to the loop goes dead in the parser, - // due to parse-time optimization. (Could happen with obfuscated code.) + if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) { + // In the absence of irreducible loops, the Region and Phis + // associated with a merge that doesn't involve a backedge can + // be simplfied now since the RPO parsing order guarantees + // that any path which was supposed to reach here has already + // been parsed or must be dead. + Node* c = control(); + Node* result = _gvn.transform_no_reclaim(control()); + if (c != result && TraceOptoParse) { + tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx); + } + if (result != top()) { + record_for_igvn(result); + } + } - // Look for progress, or the lack of it: - if (_blocks_parsed == block_count()) { - // That's all, folks. - if (TraceOptoParse) { - tty->print_cr("All blocks parsed."); - } + // Parse the block. + do_one_block(); + + // Check for bailouts. + if (failing()) return; + } + + // with irreducible loops multiple passes might be necessary to parse everything + if (!has_irreducible || !progress) { break; } + } - // How much work was done this time around? - int new_blocks_merged = _blocks_merged - old_blocks_merged; - int new_blocks_parsed = _blocks_parsed - old_blocks_parsed; - if (new_blocks_merged == 0) { - if (TraceOptoParse) { - tty->print_cr("All live blocks parsed; %d dead blocks.", block_count() - _blocks_parsed); - } - // No new blocks have become parseable. Some blocks are just dead. - break; - } - assert(new_blocks_parsed > 0, "must make progress"); - assert(tries < block_count(), "the pre-order cannot be this bad!"); - - old_blocks_merged = _blocks_merged; - old_blocks_parsed = _blocks_parsed; - } + blocks_seen += block_count(); #ifndef PRODUCT // Make sure there are no half-processed blocks remaining. // Every remaining unprocessed block is dead and may be ignored now. - for (int po = 0; po < block_count(); po++) { - Block* block = pre_order_at(po); + for (int rpo = 0; rpo < block_count(); rpo++) { + Block* block = rpo_at(rpo); if (!block->is_parsed()) { if (TraceOptoParse) { - tty->print("Skipped dead block %d at bci:%d", po, block->start()); - assert(!block->is_merged(), "no half-processed blocks"); + tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start()); } + assert(!block->is_merged(), "no half-processed blocks"); } } #endif } -//---------------------------visit_blocks-------------------------------------- -void Parse::visit_blocks() { - // Walk over all blocks, parsing every one that has been reached (merged). - for (int po = 0; po < block_count(); po++) { - Block* block = pre_order_at(po); - - if (block->is_parsed()) { - // Do not parse twice. - continue; - } - - if (!block->is_merged()) { - // No state on this block. It had not yet been reached. - // Delay reaching it until later. - continue; - } - - // Prepare to parse this block. - load_state_from(block); - - if (stopped()) { - // Block is dead. - continue; - } - - if (!block->is_ready() || block->is_handler()) { - // Not all preds have been parsed. We must build phis everywhere. - // (Note that dead locals do not get phis built, ever.) - ensure_phis_everywhere(); - - // Leave behind an undisturbed copy of the map, for future merges. - set_map(clone_map()); - } - - // Ready or not, parse the block. - do_one_block(); - - // Check for bailouts. - if (failing()) return; - } -} - //-------------------------------build_exits---------------------------------- // Build normal and exceptional exit merge points. void Parse::build_exits() { @@ -1134,24 +1116,24 @@ _blocks = NEW_RESOURCE_ARRAY(Block, _block_count); Copy::zero_to_bytes(_blocks, sizeof(Block)*_block_count); - int po; + int rpo; // Initialize the structs. - for (po = 0; po < block_count(); po++) { - Block* block = pre_order_at(po); - block->init_node(this, po); + for (rpo = 0; rpo < block_count(); rpo++) { + Block* block = rpo_at(rpo); + block->init_node(this, rpo); } // Collect predecessor and successor information. - for (po = 0; po < block_count(); po++) { - Block* block = pre_order_at(po); + for (rpo = 0; rpo < block_count(); rpo++) { + Block* block = rpo_at(rpo); block->init_graph(this); } } //-------------------------------init_node------------------------------------- -void Parse::Block::init_node(Parse* outer, int po) { - _flow = outer->flow()->pre_order_at(po); +void Parse::Block::init_node(Parse* outer, int rpo) { + _flow = outer->flow()->rpo_at(rpo); _pred_count = 0; _preds_parsed = 0; _count = 0; @@ -1177,7 +1159,7 @@ int p = 0; for (int i = 0; i < ns+ne; i++) { ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns); - Block* block2 = outer->pre_order_at(tf2->pre_order()); + Block* block2 = outer->rpo_at(tf2->rpo()); _successors[i] = block2; // Accumulate pred info for the other block, too. @@ -1368,10 +1350,11 @@ int nt = b->all_successors(); tty->print("Parsing block #%d at bci [%d,%d), successors: ", - block()->pre_order(), block()->start(), block()->limit()); + block()->rpo(), block()->start(), block()->limit()); for (int i = 0; i < nt; i++) { - tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->pre_order()); + tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->rpo()); } + if (b->is_loop_head()) tty->print(" lphd"); tty->print_cr(""); } @@ -1501,7 +1484,7 @@ #ifndef PRODUCT Block* b = block(); int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1; - tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->pre_order(), trap_bci); + tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci); #endif ShouldNotReachHere(); } @@ -1509,7 +1492,7 @@ //--------------------------merge_common--------------------------------------- void Parse::merge_common(Parse::Block* target, int pnum) { if (TraceOptoParse) { - tty->print("Merging state at block #%d bci:%d", target->pre_order(), target->start()); + tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start()); } // Zap extra stack slots to top @@ -1534,6 +1517,7 @@ // which must not be allowed into this block's map.) if (pnum > PhiNode::Input // Known multiple inputs. || target->is_handler() // These have unpredictable inputs. + || target->is_loop_head() // Known multiple inputs || control()->is_Region()) { // We must hide this guy. // Add a Region to start the new basic block. Phis will be added // later lazily. @@ -1575,15 +1559,21 @@ // Compute where to merge into // Merge incoming control path - r->set_req(pnum, newin->control()); + r->init_req(pnum, newin->control()); if (pnum == 1) { // Last merge for this Region? - _gvn.transform_no_reclaim(r); + if (!block()->flow()->is_irreducible_entry()) { + Node* result = _gvn.transform_no_reclaim(r); + if (r != result && TraceOptoParse) { + tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx); + } + } record_for_igvn(r); } // Update all the non-control inputs to map: assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms"); + bool check_elide_phi = target->is_SEL_backedge(save_block); for (uint j = 1; j < newin->req(); j++) { Node* m = map()->in(j); // Current state of target. Node* n = newin->in(j); // Incoming change to target state. @@ -1603,7 +1593,11 @@ merge_memory_edges(n->as_MergeMem(), pnum, nophi); continue; default: // All normal stuff - if (phi == NULL) phi = ensure_phi(j, nophi); + if (phi == NULL) { + if (!check_elide_phi || !target->can_elide_SEL_phi(j)) { + phi = ensure_phi(j, nophi); + } + } break; } } @@ -1736,9 +1730,13 @@ uint nof_monitors = map()->jvms()->nof_monitors(); assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms"); + bool check_elide_phi = block()->is_SEL_head(); for (uint i = TypeFunc::Parms; i < monoff; i++) { - ensure_phi(i); + if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) { + ensure_phi(i); + } } + // Even monitors need Phis, though they are well-structured. // This is true for OSR methods, and also for the rare cases where // a monitor object is the subject of a replace_in_map operation.