Tue, 09 Mar 2010 20:16:19 +0100
6919934: JSR 292 needs to support x86 C1
Summary: This implements JSR 292 support for C1 x86.
Reviewed-by: never, jrose, kvn
duke@435 | 1 | /* |
xdono@1014 | 2 | * Copyright 1999-2009 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | #include "incls/_precompiled.incl" |
duke@435 | 26 | #include "incls/_c1_Optimizer.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | define_array(ValueSetArray, ValueSet*); |
duke@435 | 29 | define_stack(ValueSetList, ValueSetArray); |
duke@435 | 30 | |
duke@435 | 31 | |
duke@435 | 32 | Optimizer::Optimizer(IR* ir) { |
duke@435 | 33 | assert(ir->is_valid(), "IR must be valid"); |
duke@435 | 34 | _ir = ir; |
duke@435 | 35 | } |
duke@435 | 36 | |
duke@435 | 37 | class CE_Eliminator: public BlockClosure { |
duke@435 | 38 | private: |
duke@435 | 39 | IR* _hir; |
duke@435 | 40 | int _cee_count; // the number of CEs successfully eliminated |
duke@435 | 41 | int _has_substitution; |
duke@435 | 42 | |
duke@435 | 43 | public: |
duke@435 | 44 | CE_Eliminator(IR* hir) : _cee_count(0), _hir(hir) { |
duke@435 | 45 | _has_substitution = false; |
duke@435 | 46 | _hir->iterate_preorder(this); |
duke@435 | 47 | if (_has_substitution) { |
duke@435 | 48 | // substituted some phis so resolve the substitution |
duke@435 | 49 | SubstitutionResolver sr(_hir); |
duke@435 | 50 | } |
duke@435 | 51 | } |
duke@435 | 52 | int cee_count() const { return _cee_count; } |
duke@435 | 53 | |
duke@435 | 54 | void adjust_exception_edges(BlockBegin* block, BlockBegin* sux) { |
duke@435 | 55 | int e = sux->number_of_exception_handlers(); |
duke@435 | 56 | for (int i = 0; i < e; i++) { |
duke@435 | 57 | BlockBegin* xhandler = sux->exception_handler_at(i); |
duke@435 | 58 | block->add_exception_handler(xhandler); |
duke@435 | 59 | |
duke@435 | 60 | assert(xhandler->is_predecessor(sux), "missing predecessor"); |
duke@435 | 61 | if (sux->number_of_preds() == 0) { |
duke@435 | 62 | // sux is disconnected from graph so disconnect from exception handlers |
duke@435 | 63 | xhandler->remove_predecessor(sux); |
duke@435 | 64 | } |
duke@435 | 65 | if (!xhandler->is_predecessor(block)) { |
duke@435 | 66 | xhandler->add_predecessor(block); |
duke@435 | 67 | } |
duke@435 | 68 | } |
duke@435 | 69 | } |
duke@435 | 70 | |
duke@435 | 71 | virtual void block_do(BlockBegin* block) { |
duke@435 | 72 | // 1) find conditional expression |
duke@435 | 73 | // check if block ends with an If |
duke@435 | 74 | If* if_ = block->end()->as_If(); |
duke@435 | 75 | if (if_ == NULL) return; |
duke@435 | 76 | |
duke@435 | 77 | // check if If works on int or object types |
duke@435 | 78 | // (we cannot handle If's working on long, float or doubles yet, |
duke@435 | 79 | // since IfOp doesn't support them - these If's show up if cmp |
duke@435 | 80 | // operations followed by If's are eliminated) |
duke@435 | 81 | ValueType* if_type = if_->x()->type(); |
duke@435 | 82 | if (!if_type->is_int() && !if_type->is_object()) return; |
duke@435 | 83 | |
duke@435 | 84 | BlockBegin* t_block = if_->tsux(); |
duke@435 | 85 | BlockBegin* f_block = if_->fsux(); |
duke@435 | 86 | Instruction* t_cur = t_block->next(); |
duke@435 | 87 | Instruction* f_cur = f_block->next(); |
duke@435 | 88 | |
duke@435 | 89 | // one Constant may be present between BlockBegin and BlockEnd |
duke@435 | 90 | Value t_const = NULL; |
duke@435 | 91 | Value f_const = NULL; |
duke@435 | 92 | if (t_cur->as_Constant() != NULL && !t_cur->can_trap()) { |
duke@435 | 93 | t_const = t_cur; |
duke@435 | 94 | t_cur = t_cur->next(); |
duke@435 | 95 | } |
duke@435 | 96 | if (f_cur->as_Constant() != NULL && !f_cur->can_trap()) { |
duke@435 | 97 | f_const = f_cur; |
duke@435 | 98 | f_cur = f_cur->next(); |
duke@435 | 99 | } |
duke@435 | 100 | |
duke@435 | 101 | // check if both branches end with a goto |
duke@435 | 102 | Goto* t_goto = t_cur->as_Goto(); |
duke@435 | 103 | if (t_goto == NULL) return; |
duke@435 | 104 | Goto* f_goto = f_cur->as_Goto(); |
duke@435 | 105 | if (f_goto == NULL) return; |
duke@435 | 106 | |
duke@435 | 107 | // check if both gotos merge into the same block |
duke@435 | 108 | BlockBegin* sux = t_goto->default_sux(); |
duke@435 | 109 | if (sux != f_goto->default_sux()) return; |
duke@435 | 110 | |
duke@435 | 111 | // check if at least one word was pushed on sux_state |
duke@435 | 112 | ValueStack* sux_state = sux->state(); |
duke@435 | 113 | if (sux_state->stack_size() <= if_->state()->stack_size()) return; |
duke@435 | 114 | |
duke@435 | 115 | // check if phi function is present at end of successor stack and that |
duke@435 | 116 | // only this phi was pushed on the stack |
duke@435 | 117 | Value sux_phi = sux_state->stack_at(if_->state()->stack_size()); |
duke@435 | 118 | if (sux_phi == NULL || sux_phi->as_Phi() == NULL || sux_phi->as_Phi()->block() != sux) return; |
duke@435 | 119 | if (sux_phi->type()->size() != sux_state->stack_size() - if_->state()->stack_size()) return; |
duke@435 | 120 | |
duke@435 | 121 | // get the values that were pushed in the true- and false-branch |
duke@435 | 122 | Value t_value = t_goto->state()->stack_at(if_->state()->stack_size()); |
duke@435 | 123 | Value f_value = f_goto->state()->stack_at(if_->state()->stack_size()); |
duke@435 | 124 | |
duke@435 | 125 | // backend does not support floats |
duke@435 | 126 | assert(t_value->type()->base() == f_value->type()->base(), "incompatible types"); |
duke@435 | 127 | if (t_value->type()->is_float_kind()) return; |
duke@435 | 128 | |
duke@435 | 129 | // check that successor has no other phi functions but sux_phi |
duke@435 | 130 | // this can happen when t_block or f_block contained additonal stores to local variables |
duke@435 | 131 | // that are no longer represented by explicit instructions |
duke@435 | 132 | for_each_phi_fun(sux, phi, |
duke@435 | 133 | if (phi != sux_phi) return; |
duke@435 | 134 | ); |
duke@435 | 135 | // true and false blocks can't have phis |
duke@435 | 136 | for_each_phi_fun(t_block, phi, return; ); |
duke@435 | 137 | for_each_phi_fun(f_block, phi, return; ); |
duke@435 | 138 | |
duke@435 | 139 | // 2) substitute conditional expression |
duke@435 | 140 | // with an IfOp followed by a Goto |
duke@435 | 141 | // cut if_ away and get node before |
duke@435 | 142 | Instruction* cur_end = if_->prev(block); |
duke@435 | 143 | int bci = if_->bci(); |
duke@435 | 144 | |
duke@435 | 145 | // append constants of true- and false-block if necessary |
duke@435 | 146 | // clone constants because original block must not be destroyed |
duke@435 | 147 | assert((t_value != f_const && f_value != t_const) || t_const == f_const, "mismatch"); |
duke@435 | 148 | if (t_value == t_const) { |
duke@435 | 149 | t_value = new Constant(t_const->type()); |
duke@435 | 150 | cur_end = cur_end->set_next(t_value, bci); |
duke@435 | 151 | } |
duke@435 | 152 | if (f_value == f_const) { |
duke@435 | 153 | f_value = new Constant(f_const->type()); |
duke@435 | 154 | cur_end = cur_end->set_next(f_value, bci); |
duke@435 | 155 | } |
duke@435 | 156 | |
duke@435 | 157 | // it is very unlikely that the condition can be statically decided |
duke@435 | 158 | // (this was checked previously by the Canonicalizer), so always |
duke@435 | 159 | // append IfOp |
duke@435 | 160 | Value result = new IfOp(if_->x(), if_->cond(), if_->y(), t_value, f_value); |
duke@435 | 161 | cur_end = cur_end->set_next(result, bci); |
duke@435 | 162 | |
duke@435 | 163 | // append Goto to successor |
duke@435 | 164 | ValueStack* state_before = if_->is_safepoint() ? if_->state_before() : NULL; |
duke@435 | 165 | Goto* goto_ = new Goto(sux, state_before, if_->is_safepoint() || t_goto->is_safepoint() || f_goto->is_safepoint()); |
duke@435 | 166 | |
duke@435 | 167 | // prepare state for Goto |
duke@435 | 168 | ValueStack* goto_state = if_->state(); |
duke@435 | 169 | while (sux_state->scope() != goto_state->scope()) { |
duke@435 | 170 | goto_state = goto_state->pop_scope(); |
duke@435 | 171 | assert(goto_state != NULL, "states do not match up"); |
duke@435 | 172 | } |
duke@435 | 173 | goto_state = goto_state->copy(); |
duke@435 | 174 | goto_state->push(result->type(), result); |
duke@435 | 175 | assert(goto_state->is_same_across_scopes(sux_state), "states must match now"); |
duke@435 | 176 | goto_->set_state(goto_state); |
duke@435 | 177 | |
duke@435 | 178 | // Steal the bci for the goto from the sux |
duke@435 | 179 | cur_end = cur_end->set_next(goto_, sux->bci()); |
duke@435 | 180 | |
duke@435 | 181 | // Adjust control flow graph |
duke@435 | 182 | BlockBegin::disconnect_edge(block, t_block); |
duke@435 | 183 | BlockBegin::disconnect_edge(block, f_block); |
duke@435 | 184 | if (t_block->number_of_preds() == 0) { |
duke@435 | 185 | BlockBegin::disconnect_edge(t_block, sux); |
duke@435 | 186 | } |
duke@435 | 187 | adjust_exception_edges(block, t_block); |
duke@435 | 188 | if (f_block->number_of_preds() == 0) { |
duke@435 | 189 | BlockBegin::disconnect_edge(f_block, sux); |
duke@435 | 190 | } |
duke@435 | 191 | adjust_exception_edges(block, f_block); |
duke@435 | 192 | |
duke@435 | 193 | // update block end |
duke@435 | 194 | block->set_end(goto_); |
duke@435 | 195 | |
duke@435 | 196 | // substitute the phi if possible |
duke@435 | 197 | if (sux_phi->as_Phi()->operand_count() == 1) { |
duke@435 | 198 | assert(sux_phi->as_Phi()->operand_at(0) == result, "screwed up phi"); |
duke@435 | 199 | sux_phi->set_subst(result); |
duke@435 | 200 | _has_substitution = true; |
duke@435 | 201 | } |
duke@435 | 202 | |
duke@435 | 203 | // 3) successfully eliminated a conditional expression |
duke@435 | 204 | _cee_count++; |
duke@435 | 205 | if (PrintCEE) { |
duke@435 | 206 | tty->print_cr("%d. CEE in B%d (B%d B%d)", cee_count(), block->block_id(), t_block->block_id(), f_block->block_id()); |
duke@435 | 207 | } |
duke@435 | 208 | |
duke@435 | 209 | _hir->verify(); |
duke@435 | 210 | } |
duke@435 | 211 | }; |
duke@435 | 212 | |
duke@435 | 213 | |
duke@435 | 214 | void Optimizer::eliminate_conditional_expressions() { |
duke@435 | 215 | // find conditional expressions & replace them with IfOps |
duke@435 | 216 | CE_Eliminator ce(ir()); |
duke@435 | 217 | } |
duke@435 | 218 | |
duke@435 | 219 | |
duke@435 | 220 | class BlockMerger: public BlockClosure { |
duke@435 | 221 | private: |
duke@435 | 222 | IR* _hir; |
duke@435 | 223 | int _merge_count; // the number of block pairs successfully merged |
duke@435 | 224 | |
duke@435 | 225 | public: |
duke@435 | 226 | BlockMerger(IR* hir) |
duke@435 | 227 | : _hir(hir) |
duke@435 | 228 | , _merge_count(0) |
duke@435 | 229 | { |
duke@435 | 230 | _hir->iterate_preorder(this); |
duke@435 | 231 | } |
duke@435 | 232 | |
duke@435 | 233 | bool try_merge(BlockBegin* block) { |
duke@435 | 234 | BlockEnd* end = block->end(); |
duke@435 | 235 | if (end->as_Goto() != NULL) { |
duke@435 | 236 | assert(end->number_of_sux() == 1, "end must have exactly one successor"); |
duke@435 | 237 | // Note: It would be sufficient to check for the number of successors (= 1) |
duke@435 | 238 | // in order to decide if this block can be merged potentially. That |
duke@435 | 239 | // would then also include switch statements w/ only a default case. |
duke@435 | 240 | // However, in that case we would need to make sure the switch tag |
duke@435 | 241 | // expression is executed if it can produce observable side effects. |
duke@435 | 242 | // We should probably have the canonicalizer simplifying such switch |
duke@435 | 243 | // statements and then we are sure we don't miss these merge opportunities |
duke@435 | 244 | // here (was bug - gri 7/7/99). |
duke@435 | 245 | BlockBegin* sux = end->default_sux(); |
duke@435 | 246 | if (sux->number_of_preds() == 1 && !sux->is_entry_block() && !end->is_safepoint()) { |
duke@435 | 247 | // merge the two blocks |
duke@435 | 248 | |
duke@435 | 249 | #ifdef ASSERT |
duke@435 | 250 | // verify that state at the end of block and at the beginning of sux are equal |
duke@435 | 251 | // no phi functions must be present at beginning of sux |
duke@435 | 252 | ValueStack* sux_state = sux->state(); |
duke@435 | 253 | ValueStack* end_state = end->state(); |
duke@435 | 254 | while (end_state->scope() != sux_state->scope()) { |
duke@435 | 255 | // match up inlining level |
duke@435 | 256 | end_state = end_state->pop_scope(); |
duke@435 | 257 | } |
duke@435 | 258 | assert(end_state->stack_size() == sux_state->stack_size(), "stack not equal"); |
duke@435 | 259 | assert(end_state->locals_size() == sux_state->locals_size(), "locals not equal"); |
duke@435 | 260 | |
duke@435 | 261 | int index; |
duke@435 | 262 | Value sux_value; |
duke@435 | 263 | for_each_stack_value(sux_state, index, sux_value) { |
duke@435 | 264 | assert(sux_value == end_state->stack_at(index), "stack not equal"); |
duke@435 | 265 | } |
duke@435 | 266 | for_each_local_value(sux_state, index, sux_value) { |
duke@435 | 267 | assert(sux_value == end_state->local_at(index), "locals not equal"); |
duke@435 | 268 | } |
duke@435 | 269 | assert(sux_state->caller_state() == end_state->caller_state(), "caller not equal"); |
duke@435 | 270 | #endif |
duke@435 | 271 | |
duke@435 | 272 | // find instruction before end & append first instruction of sux block |
duke@435 | 273 | Instruction* prev = end->prev(block); |
duke@435 | 274 | Instruction* next = sux->next(); |
duke@435 | 275 | assert(prev->as_BlockEnd() == NULL, "must not be a BlockEnd"); |
duke@435 | 276 | prev->set_next(next, next->bci()); |
duke@435 | 277 | sux->disconnect_from_graph(); |
duke@435 | 278 | block->set_end(sux->end()); |
duke@435 | 279 | // add exception handlers of deleted block, if any |
duke@435 | 280 | for (int k = 0; k < sux->number_of_exception_handlers(); k++) { |
duke@435 | 281 | BlockBegin* xhandler = sux->exception_handler_at(k); |
duke@435 | 282 | block->add_exception_handler(xhandler); |
duke@435 | 283 | |
duke@435 | 284 | // also substitute predecessor of exception handler |
duke@435 | 285 | assert(xhandler->is_predecessor(sux), "missing predecessor"); |
duke@435 | 286 | xhandler->remove_predecessor(sux); |
duke@435 | 287 | if (!xhandler->is_predecessor(block)) { |
duke@435 | 288 | xhandler->add_predecessor(block); |
duke@435 | 289 | } |
duke@435 | 290 | } |
duke@435 | 291 | |
duke@435 | 292 | // debugging output |
duke@435 | 293 | _merge_count++; |
duke@435 | 294 | if (PrintBlockElimination) { |
duke@435 | 295 | tty->print_cr("%d. merged B%d & B%d (stack size = %d)", |
duke@435 | 296 | _merge_count, block->block_id(), sux->block_id(), sux->state()->stack_size()); |
duke@435 | 297 | } |
duke@435 | 298 | |
duke@435 | 299 | _hir->verify(); |
duke@435 | 300 | |
duke@435 | 301 | If* if_ = block->end()->as_If(); |
duke@435 | 302 | if (if_) { |
duke@435 | 303 | IfOp* ifop = if_->x()->as_IfOp(); |
duke@435 | 304 | Constant* con = if_->y()->as_Constant(); |
duke@435 | 305 | bool swapped = false; |
duke@435 | 306 | if (!con || !ifop) { |
duke@435 | 307 | ifop = if_->y()->as_IfOp(); |
duke@435 | 308 | con = if_->x()->as_Constant(); |
duke@435 | 309 | swapped = true; |
duke@435 | 310 | } |
duke@435 | 311 | if (con && ifop) { |
duke@435 | 312 | Constant* tval = ifop->tval()->as_Constant(); |
duke@435 | 313 | Constant* fval = ifop->fval()->as_Constant(); |
duke@435 | 314 | if (tval && fval) { |
duke@435 | 315 | // Find the instruction before if_, starting with ifop. |
duke@435 | 316 | // When if_ and ifop are not in the same block, prev |
duke@435 | 317 | // becomes NULL In such (rare) cases it is not |
duke@435 | 318 | // profitable to perform the optimization. |
duke@435 | 319 | Value prev = ifop; |
duke@435 | 320 | while (prev != NULL && prev->next() != if_) { |
duke@435 | 321 | prev = prev->next(); |
duke@435 | 322 | } |
duke@435 | 323 | |
duke@435 | 324 | if (prev != NULL) { |
duke@435 | 325 | Instruction::Condition cond = if_->cond(); |
duke@435 | 326 | BlockBegin* tsux = if_->tsux(); |
duke@435 | 327 | BlockBegin* fsux = if_->fsux(); |
duke@435 | 328 | if (swapped) { |
duke@435 | 329 | cond = Instruction::mirror(cond); |
duke@435 | 330 | } |
duke@435 | 331 | |
duke@435 | 332 | BlockBegin* tblock = tval->compare(cond, con, tsux, fsux); |
duke@435 | 333 | BlockBegin* fblock = fval->compare(cond, con, tsux, fsux); |
duke@435 | 334 | if (tblock != fblock && !if_->is_safepoint()) { |
duke@435 | 335 | If* newif = new If(ifop->x(), ifop->cond(), false, ifop->y(), |
duke@435 | 336 | tblock, fblock, if_->state_before(), if_->is_safepoint()); |
duke@435 | 337 | newif->set_state(if_->state()->copy()); |
duke@435 | 338 | |
duke@435 | 339 | assert(prev->next() == if_, "must be guaranteed by above search"); |
duke@435 | 340 | prev->set_next(newif, if_->bci()); |
duke@435 | 341 | block->set_end(newif); |
duke@435 | 342 | |
duke@435 | 343 | _merge_count++; |
duke@435 | 344 | if (PrintBlockElimination) { |
duke@435 | 345 | tty->print_cr("%d. replaced If and IfOp at end of B%d with single If", _merge_count, block->block_id()); |
duke@435 | 346 | } |
duke@435 | 347 | |
duke@435 | 348 | _hir->verify(); |
duke@435 | 349 | } |
duke@435 | 350 | } |
duke@435 | 351 | } |
duke@435 | 352 | } |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | return true; |
duke@435 | 356 | } |
duke@435 | 357 | } |
duke@435 | 358 | return false; |
duke@435 | 359 | } |
duke@435 | 360 | |
duke@435 | 361 | virtual void block_do(BlockBegin* block) { |
duke@435 | 362 | _hir->verify(); |
duke@435 | 363 | // repeat since the same block may merge again |
duke@435 | 364 | while (try_merge(block)) { |
duke@435 | 365 | _hir->verify(); |
duke@435 | 366 | } |
duke@435 | 367 | } |
duke@435 | 368 | }; |
duke@435 | 369 | |
duke@435 | 370 | |
duke@435 | 371 | void Optimizer::eliminate_blocks() { |
duke@435 | 372 | // merge blocks if possible |
duke@435 | 373 | BlockMerger bm(ir()); |
duke@435 | 374 | } |
duke@435 | 375 | |
duke@435 | 376 | |
duke@435 | 377 | class NullCheckEliminator; |
duke@435 | 378 | class NullCheckVisitor: public InstructionVisitor { |
duke@435 | 379 | private: |
duke@435 | 380 | NullCheckEliminator* _nce; |
duke@435 | 381 | NullCheckEliminator* nce() { return _nce; } |
duke@435 | 382 | |
duke@435 | 383 | public: |
duke@435 | 384 | NullCheckVisitor() {} |
duke@435 | 385 | |
duke@435 | 386 | void set_eliminator(NullCheckEliminator* nce) { _nce = nce; } |
duke@435 | 387 | |
duke@435 | 388 | void do_Phi (Phi* x); |
duke@435 | 389 | void do_Local (Local* x); |
duke@435 | 390 | void do_Constant (Constant* x); |
duke@435 | 391 | void do_LoadField (LoadField* x); |
duke@435 | 392 | void do_StoreField (StoreField* x); |
duke@435 | 393 | void do_ArrayLength (ArrayLength* x); |
duke@435 | 394 | void do_LoadIndexed (LoadIndexed* x); |
duke@435 | 395 | void do_StoreIndexed (StoreIndexed* x); |
duke@435 | 396 | void do_NegateOp (NegateOp* x); |
duke@435 | 397 | void do_ArithmeticOp (ArithmeticOp* x); |
duke@435 | 398 | void do_ShiftOp (ShiftOp* x); |
duke@435 | 399 | void do_LogicOp (LogicOp* x); |
duke@435 | 400 | void do_CompareOp (CompareOp* x); |
duke@435 | 401 | void do_IfOp (IfOp* x); |
duke@435 | 402 | void do_Convert (Convert* x); |
duke@435 | 403 | void do_NullCheck (NullCheck* x); |
duke@435 | 404 | void do_Invoke (Invoke* x); |
duke@435 | 405 | void do_NewInstance (NewInstance* x); |
duke@435 | 406 | void do_NewTypeArray (NewTypeArray* x); |
duke@435 | 407 | void do_NewObjectArray (NewObjectArray* x); |
duke@435 | 408 | void do_NewMultiArray (NewMultiArray* x); |
duke@435 | 409 | void do_CheckCast (CheckCast* x); |
duke@435 | 410 | void do_InstanceOf (InstanceOf* x); |
duke@435 | 411 | void do_MonitorEnter (MonitorEnter* x); |
duke@435 | 412 | void do_MonitorExit (MonitorExit* x); |
duke@435 | 413 | void do_Intrinsic (Intrinsic* x); |
duke@435 | 414 | void do_BlockBegin (BlockBegin* x); |
duke@435 | 415 | void do_Goto (Goto* x); |
duke@435 | 416 | void do_If (If* x); |
duke@435 | 417 | void do_IfInstanceOf (IfInstanceOf* x); |
duke@435 | 418 | void do_TableSwitch (TableSwitch* x); |
duke@435 | 419 | void do_LookupSwitch (LookupSwitch* x); |
duke@435 | 420 | void do_Return (Return* x); |
duke@435 | 421 | void do_Throw (Throw* x); |
duke@435 | 422 | void do_Base (Base* x); |
duke@435 | 423 | void do_OsrEntry (OsrEntry* x); |
duke@435 | 424 | void do_ExceptionObject(ExceptionObject* x); |
duke@435 | 425 | void do_RoundFP (RoundFP* x); |
duke@435 | 426 | void do_UnsafeGetRaw (UnsafeGetRaw* x); |
duke@435 | 427 | void do_UnsafePutRaw (UnsafePutRaw* x); |
duke@435 | 428 | void do_UnsafeGetObject(UnsafeGetObject* x); |
duke@435 | 429 | void do_UnsafePutObject(UnsafePutObject* x); |
duke@435 | 430 | void do_UnsafePrefetchRead (UnsafePrefetchRead* x); |
duke@435 | 431 | void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x); |
duke@435 | 432 | void do_ProfileCall (ProfileCall* x); |
duke@435 | 433 | void do_ProfileCounter (ProfileCounter* x); |
duke@435 | 434 | }; |
duke@435 | 435 | |
duke@435 | 436 | |
duke@435 | 437 | // Because of a static contained within (for the purpose of iteration |
duke@435 | 438 | // over instructions), it is only valid to have one of these active at |
duke@435 | 439 | // a time |
duke@435 | 440 | class NullCheckEliminator { |
duke@435 | 441 | private: |
duke@435 | 442 | static NullCheckEliminator* _static_nce; |
duke@435 | 443 | static void do_value(Value* vp); |
duke@435 | 444 | |
duke@435 | 445 | Optimizer* _opt; |
duke@435 | 446 | |
duke@435 | 447 | ValueSet* _visitable_instructions; // Visit each instruction only once per basic block |
duke@435 | 448 | BlockList* _work_list; // Basic blocks to visit |
duke@435 | 449 | |
duke@435 | 450 | bool visitable(Value x) { |
duke@435 | 451 | assert(_visitable_instructions != NULL, "check"); |
duke@435 | 452 | return _visitable_instructions->contains(x); |
duke@435 | 453 | } |
duke@435 | 454 | void mark_visited(Value x) { |
duke@435 | 455 | assert(_visitable_instructions != NULL, "check"); |
duke@435 | 456 | _visitable_instructions->remove(x); |
duke@435 | 457 | } |
duke@435 | 458 | void mark_visitable(Value x) { |
duke@435 | 459 | assert(_visitable_instructions != NULL, "check"); |
duke@435 | 460 | _visitable_instructions->put(x); |
duke@435 | 461 | } |
duke@435 | 462 | void clear_visitable_state() { |
duke@435 | 463 | assert(_visitable_instructions != NULL, "check"); |
duke@435 | 464 | _visitable_instructions->clear(); |
duke@435 | 465 | } |
duke@435 | 466 | |
duke@435 | 467 | ValueSet* _set; // current state, propagated to subsequent BlockBegins |
duke@435 | 468 | ValueSetList _block_states; // BlockBegin null-check states for all processed blocks |
duke@435 | 469 | NullCheckVisitor _visitor; |
duke@435 | 470 | NullCheck* _last_explicit_null_check; |
duke@435 | 471 | |
duke@435 | 472 | bool set_contains(Value x) { assert(_set != NULL, "check"); return _set->contains(x); } |
duke@435 | 473 | void set_put (Value x) { assert(_set != NULL, "check"); _set->put(x); } |
duke@435 | 474 | void set_remove (Value x) { assert(_set != NULL, "check"); _set->remove(x); } |
duke@435 | 475 | |
duke@435 | 476 | BlockList* work_list() { return _work_list; } |
duke@435 | 477 | |
duke@435 | 478 | void iterate_all(); |
duke@435 | 479 | void iterate_one(BlockBegin* block); |
duke@435 | 480 | |
duke@435 | 481 | ValueSet* state() { return _set; } |
duke@435 | 482 | void set_state_from (ValueSet* state) { _set->set_from(state); } |
duke@435 | 483 | ValueSet* state_for (BlockBegin* block) { return _block_states[block->block_id()]; } |
duke@435 | 484 | void set_state_for (BlockBegin* block, ValueSet* stack) { _block_states[block->block_id()] = stack; } |
duke@435 | 485 | // Returns true if caused a change in the block's state. |
duke@435 | 486 | bool merge_state_for(BlockBegin* block, |
duke@435 | 487 | ValueSet* incoming_state); |
duke@435 | 488 | |
duke@435 | 489 | public: |
duke@435 | 490 | // constructor |
duke@435 | 491 | NullCheckEliminator(Optimizer* opt) |
duke@435 | 492 | : _opt(opt) |
duke@435 | 493 | , _set(new ValueSet()) |
duke@435 | 494 | , _last_explicit_null_check(NULL) |
duke@435 | 495 | , _block_states(BlockBegin::number_of_blocks(), NULL) |
duke@435 | 496 | , _work_list(new BlockList()) { |
duke@435 | 497 | _visitable_instructions = new ValueSet(); |
duke@435 | 498 | _visitor.set_eliminator(this); |
duke@435 | 499 | } |
duke@435 | 500 | |
duke@435 | 501 | Optimizer* opt() { return _opt; } |
duke@435 | 502 | IR* ir () { return opt()->ir(); } |
duke@435 | 503 | |
duke@435 | 504 | // Process a graph |
duke@435 | 505 | void iterate(BlockBegin* root); |
duke@435 | 506 | |
duke@435 | 507 | // In some situations (like NullCheck(x); getfield(x)) the debug |
duke@435 | 508 | // information from the explicit NullCheck can be used to populate |
duke@435 | 509 | // the getfield, even if the two instructions are in different |
duke@435 | 510 | // scopes; this allows implicit null checks to be used but the |
duke@435 | 511 | // correct exception information to be generated. We must clear the |
duke@435 | 512 | // last-traversed NullCheck when we reach a potentially-exception- |
duke@435 | 513 | // throwing instruction, as well as in some other cases. |
duke@435 | 514 | void set_last_explicit_null_check(NullCheck* check) { _last_explicit_null_check = check; } |
duke@435 | 515 | NullCheck* last_explicit_null_check() { return _last_explicit_null_check; } |
duke@435 | 516 | Value last_explicit_null_check_obj() { return (_last_explicit_null_check |
duke@435 | 517 | ? _last_explicit_null_check->obj() |
duke@435 | 518 | : NULL); } |
duke@435 | 519 | NullCheck* consume_last_explicit_null_check() { |
duke@435 | 520 | _last_explicit_null_check->unpin(Instruction::PinExplicitNullCheck); |
duke@435 | 521 | _last_explicit_null_check->set_can_trap(false); |
duke@435 | 522 | return _last_explicit_null_check; |
duke@435 | 523 | } |
duke@435 | 524 | void clear_last_explicit_null_check() { _last_explicit_null_check = NULL; } |
duke@435 | 525 | |
duke@435 | 526 | // Handlers for relevant instructions |
duke@435 | 527 | // (separated out from NullCheckVisitor for clarity) |
duke@435 | 528 | |
duke@435 | 529 | // The basic contract is that these must leave the instruction in |
duke@435 | 530 | // the desired state; must not assume anything about the state of |
duke@435 | 531 | // the instruction. We make multiple passes over some basic blocks |
duke@435 | 532 | // and the last pass is the only one whose result is valid. |
duke@435 | 533 | void handle_AccessField (AccessField* x); |
duke@435 | 534 | void handle_ArrayLength (ArrayLength* x); |
duke@435 | 535 | void handle_LoadIndexed (LoadIndexed* x); |
duke@435 | 536 | void handle_StoreIndexed (StoreIndexed* x); |
duke@435 | 537 | void handle_NullCheck (NullCheck* x); |
duke@435 | 538 | void handle_Invoke (Invoke* x); |
duke@435 | 539 | void handle_NewInstance (NewInstance* x); |
duke@435 | 540 | void handle_NewArray (NewArray* x); |
duke@435 | 541 | void handle_AccessMonitor (AccessMonitor* x); |
duke@435 | 542 | void handle_Intrinsic (Intrinsic* x); |
duke@435 | 543 | void handle_ExceptionObject (ExceptionObject* x); |
duke@435 | 544 | void handle_Phi (Phi* x); |
duke@435 | 545 | }; |
duke@435 | 546 | |
duke@435 | 547 | |
duke@435 | 548 | // NEEDS_CLEANUP |
duke@435 | 549 | // There may be other instructions which need to clear the last |
duke@435 | 550 | // explicit null check. Anything across which we can not hoist the |
duke@435 | 551 | // debug information for a NullCheck instruction must clear it. It |
duke@435 | 552 | // might be safer to pattern match "NullCheck ; {AccessField, |
duke@435 | 553 | // ArrayLength, LoadIndexed}" but it is more easily structured this way. |
duke@435 | 554 | // Should test to see performance hit of clearing it for all handlers |
duke@435 | 555 | // with empty bodies below. If it is negligible then we should leave |
duke@435 | 556 | // that in for safety, otherwise should think more about it. |
duke@435 | 557 | void NullCheckVisitor::do_Phi (Phi* x) { nce()->handle_Phi(x); } |
duke@435 | 558 | void NullCheckVisitor::do_Local (Local* x) {} |
duke@435 | 559 | void NullCheckVisitor::do_Constant (Constant* x) { /* FIXME: handle object constants */ } |
duke@435 | 560 | void NullCheckVisitor::do_LoadField (LoadField* x) { nce()->handle_AccessField(x); } |
duke@435 | 561 | void NullCheckVisitor::do_StoreField (StoreField* x) { nce()->handle_AccessField(x); } |
duke@435 | 562 | void NullCheckVisitor::do_ArrayLength (ArrayLength* x) { nce()->handle_ArrayLength(x); } |
duke@435 | 563 | void NullCheckVisitor::do_LoadIndexed (LoadIndexed* x) { nce()->handle_LoadIndexed(x); } |
duke@435 | 564 | void NullCheckVisitor::do_StoreIndexed (StoreIndexed* x) { nce()->handle_StoreIndexed(x); } |
duke@435 | 565 | void NullCheckVisitor::do_NegateOp (NegateOp* x) {} |
duke@435 | 566 | void NullCheckVisitor::do_ArithmeticOp (ArithmeticOp* x) { if (x->can_trap()) nce()->clear_last_explicit_null_check(); } |
duke@435 | 567 | void NullCheckVisitor::do_ShiftOp (ShiftOp* x) {} |
duke@435 | 568 | void NullCheckVisitor::do_LogicOp (LogicOp* x) {} |
duke@435 | 569 | void NullCheckVisitor::do_CompareOp (CompareOp* x) {} |
duke@435 | 570 | void NullCheckVisitor::do_IfOp (IfOp* x) {} |
duke@435 | 571 | void NullCheckVisitor::do_Convert (Convert* x) {} |
duke@435 | 572 | void NullCheckVisitor::do_NullCheck (NullCheck* x) { nce()->handle_NullCheck(x); } |
duke@435 | 573 | void NullCheckVisitor::do_Invoke (Invoke* x) { nce()->handle_Invoke(x); } |
duke@435 | 574 | void NullCheckVisitor::do_NewInstance (NewInstance* x) { nce()->handle_NewInstance(x); } |
duke@435 | 575 | void NullCheckVisitor::do_NewTypeArray (NewTypeArray* x) { nce()->handle_NewArray(x); } |
duke@435 | 576 | void NullCheckVisitor::do_NewObjectArray (NewObjectArray* x) { nce()->handle_NewArray(x); } |
duke@435 | 577 | void NullCheckVisitor::do_NewMultiArray (NewMultiArray* x) { nce()->handle_NewArray(x); } |
duke@435 | 578 | void NullCheckVisitor::do_CheckCast (CheckCast* x) {} |
duke@435 | 579 | void NullCheckVisitor::do_InstanceOf (InstanceOf* x) {} |
duke@435 | 580 | void NullCheckVisitor::do_MonitorEnter (MonitorEnter* x) { nce()->handle_AccessMonitor(x); } |
duke@435 | 581 | void NullCheckVisitor::do_MonitorExit (MonitorExit* x) { nce()->handle_AccessMonitor(x); } |
duke@435 | 582 | void NullCheckVisitor::do_Intrinsic (Intrinsic* x) { nce()->clear_last_explicit_null_check(); } |
duke@435 | 583 | void NullCheckVisitor::do_BlockBegin (BlockBegin* x) {} |
duke@435 | 584 | void NullCheckVisitor::do_Goto (Goto* x) {} |
duke@435 | 585 | void NullCheckVisitor::do_If (If* x) {} |
duke@435 | 586 | void NullCheckVisitor::do_IfInstanceOf (IfInstanceOf* x) {} |
duke@435 | 587 | void NullCheckVisitor::do_TableSwitch (TableSwitch* x) {} |
duke@435 | 588 | void NullCheckVisitor::do_LookupSwitch (LookupSwitch* x) {} |
duke@435 | 589 | void NullCheckVisitor::do_Return (Return* x) {} |
duke@435 | 590 | void NullCheckVisitor::do_Throw (Throw* x) { nce()->clear_last_explicit_null_check(); } |
duke@435 | 591 | void NullCheckVisitor::do_Base (Base* x) {} |
duke@435 | 592 | void NullCheckVisitor::do_OsrEntry (OsrEntry* x) {} |
duke@435 | 593 | void NullCheckVisitor::do_ExceptionObject(ExceptionObject* x) { nce()->handle_ExceptionObject(x); } |
duke@435 | 594 | void NullCheckVisitor::do_RoundFP (RoundFP* x) {} |
duke@435 | 595 | void NullCheckVisitor::do_UnsafeGetRaw (UnsafeGetRaw* x) {} |
duke@435 | 596 | void NullCheckVisitor::do_UnsafePutRaw (UnsafePutRaw* x) {} |
duke@435 | 597 | void NullCheckVisitor::do_UnsafeGetObject(UnsafeGetObject* x) {} |
duke@435 | 598 | void NullCheckVisitor::do_UnsafePutObject(UnsafePutObject* x) {} |
duke@435 | 599 | void NullCheckVisitor::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {} |
duke@435 | 600 | void NullCheckVisitor::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {} |
duke@435 | 601 | void NullCheckVisitor::do_ProfileCall (ProfileCall* x) { nce()->clear_last_explicit_null_check(); } |
duke@435 | 602 | void NullCheckVisitor::do_ProfileCounter (ProfileCounter* x) {} |
duke@435 | 603 | |
duke@435 | 604 | |
duke@435 | 605 | NullCheckEliminator* NullCheckEliminator::_static_nce = NULL; |
duke@435 | 606 | |
duke@435 | 607 | |
duke@435 | 608 | void NullCheckEliminator::do_value(Value* p) { |
duke@435 | 609 | assert(*p != NULL, "should not find NULL instructions"); |
duke@435 | 610 | if (_static_nce->visitable(*p)) { |
duke@435 | 611 | _static_nce->mark_visited(*p); |
duke@435 | 612 | (*p)->visit(&_static_nce->_visitor); |
duke@435 | 613 | } |
duke@435 | 614 | } |
duke@435 | 615 | |
duke@435 | 616 | bool NullCheckEliminator::merge_state_for(BlockBegin* block, ValueSet* incoming_state) { |
duke@435 | 617 | ValueSet* state = state_for(block); |
duke@435 | 618 | if (state == NULL) { |
duke@435 | 619 | state = incoming_state->copy(); |
duke@435 | 620 | set_state_for(block, state); |
duke@435 | 621 | return true; |
duke@435 | 622 | } else { |
duke@435 | 623 | bool changed = state->set_intersect(incoming_state); |
duke@435 | 624 | if (PrintNullCheckElimination && changed) { |
duke@435 | 625 | tty->print_cr("Block %d's null check state changed", block->block_id()); |
duke@435 | 626 | } |
duke@435 | 627 | return changed; |
duke@435 | 628 | } |
duke@435 | 629 | } |
duke@435 | 630 | |
duke@435 | 631 | |
duke@435 | 632 | void NullCheckEliminator::iterate_all() { |
duke@435 | 633 | while (work_list()->length() > 0) { |
duke@435 | 634 | iterate_one(work_list()->pop()); |
duke@435 | 635 | } |
duke@435 | 636 | } |
duke@435 | 637 | |
duke@435 | 638 | |
duke@435 | 639 | void NullCheckEliminator::iterate_one(BlockBegin* block) { |
duke@435 | 640 | _static_nce = this; |
duke@435 | 641 | clear_visitable_state(); |
duke@435 | 642 | // clear out an old explicit null checks |
duke@435 | 643 | set_last_explicit_null_check(NULL); |
duke@435 | 644 | |
duke@435 | 645 | if (PrintNullCheckElimination) { |
duke@435 | 646 | tty->print_cr(" ...iterating block %d in null check elimination for %s::%s%s", |
duke@435 | 647 | block->block_id(), |
duke@435 | 648 | ir()->method()->holder()->name()->as_utf8(), |
duke@435 | 649 | ir()->method()->name()->as_utf8(), |
duke@435 | 650 | ir()->method()->signature()->as_symbol()->as_utf8()); |
duke@435 | 651 | } |
duke@435 | 652 | |
duke@435 | 653 | // Create new state if none present (only happens at root) |
duke@435 | 654 | if (state_for(block) == NULL) { |
duke@435 | 655 | ValueSet* tmp_state = new ValueSet(); |
duke@435 | 656 | set_state_for(block, tmp_state); |
duke@435 | 657 | // Initial state is that local 0 (receiver) is non-null for |
duke@435 | 658 | // non-static methods |
duke@435 | 659 | ValueStack* stack = block->state(); |
duke@435 | 660 | IRScope* scope = stack->scope(); |
duke@435 | 661 | ciMethod* method = scope->method(); |
duke@435 | 662 | if (!method->is_static()) { |
duke@435 | 663 | Local* local0 = stack->local_at(0)->as_Local(); |
duke@435 | 664 | assert(local0 != NULL, "must be"); |
duke@435 | 665 | assert(local0->type() == objectType, "invalid type of receiver"); |
duke@435 | 666 | |
duke@435 | 667 | if (local0 != NULL) { |
duke@435 | 668 | // Local 0 is used in this scope |
duke@435 | 669 | tmp_state->put(local0); |
duke@435 | 670 | if (PrintNullCheckElimination) { |
duke@435 | 671 | tty->print_cr("Local 0 (value %d) proven non-null upon entry", local0->id()); |
duke@435 | 672 | } |
duke@435 | 673 | } |
duke@435 | 674 | } |
duke@435 | 675 | } |
duke@435 | 676 | |
duke@435 | 677 | // Must copy block's state to avoid mutating it during iteration |
duke@435 | 678 | // through the block -- otherwise "not-null" states can accidentally |
duke@435 | 679 | // propagate "up" through the block during processing of backward |
duke@435 | 680 | // branches and algorithm is incorrect (and does not converge) |
duke@435 | 681 | set_state_from(state_for(block)); |
duke@435 | 682 | |
duke@435 | 683 | // allow visiting of Phis belonging to this block |
duke@435 | 684 | for_each_phi_fun(block, phi, |
duke@435 | 685 | mark_visitable(phi); |
duke@435 | 686 | ); |
duke@435 | 687 | |
duke@435 | 688 | BlockEnd* e = block->end(); |
duke@435 | 689 | assert(e != NULL, "incomplete graph"); |
duke@435 | 690 | int i; |
duke@435 | 691 | |
duke@435 | 692 | // Propagate the state before this block into the exception |
duke@435 | 693 | // handlers. They aren't true successors since we aren't guaranteed |
duke@435 | 694 | // to execute the whole block before executing them. Also putting |
duke@435 | 695 | // them on first seems to help reduce the amount of iteration to |
duke@435 | 696 | // reach a fixed point. |
duke@435 | 697 | for (i = 0; i < block->number_of_exception_handlers(); i++) { |
duke@435 | 698 | BlockBegin* next = block->exception_handler_at(i); |
duke@435 | 699 | if (merge_state_for(next, state())) { |
duke@435 | 700 | if (!work_list()->contains(next)) { |
duke@435 | 701 | work_list()->push(next); |
duke@435 | 702 | } |
duke@435 | 703 | } |
duke@435 | 704 | } |
duke@435 | 705 | |
duke@435 | 706 | // Iterate through block, updating state. |
duke@435 | 707 | for (Instruction* instr = block; instr != NULL; instr = instr->next()) { |
duke@435 | 708 | // Mark instructions in this block as visitable as they are seen |
duke@435 | 709 | // in the instruction list. This keeps the iteration from |
duke@435 | 710 | // visiting instructions which are references in other blocks or |
duke@435 | 711 | // visiting instructions more than once. |
duke@435 | 712 | mark_visitable(instr); |
duke@435 | 713 | if (instr->is_root() || instr->can_trap() || (instr->as_NullCheck() != NULL)) { |
duke@435 | 714 | mark_visited(instr); |
duke@435 | 715 | instr->input_values_do(&NullCheckEliminator::do_value); |
duke@435 | 716 | instr->visit(&_visitor); |
duke@435 | 717 | } |
duke@435 | 718 | } |
duke@435 | 719 | |
duke@435 | 720 | // Propagate state to successors if necessary |
duke@435 | 721 | for (i = 0; i < e->number_of_sux(); i++) { |
duke@435 | 722 | BlockBegin* next = e->sux_at(i); |
duke@435 | 723 | if (merge_state_for(next, state())) { |
duke@435 | 724 | if (!work_list()->contains(next)) { |
duke@435 | 725 | work_list()->push(next); |
duke@435 | 726 | } |
duke@435 | 727 | } |
duke@435 | 728 | } |
duke@435 | 729 | } |
duke@435 | 730 | |
duke@435 | 731 | |
duke@435 | 732 | void NullCheckEliminator::iterate(BlockBegin* block) { |
duke@435 | 733 | work_list()->push(block); |
duke@435 | 734 | iterate_all(); |
duke@435 | 735 | } |
duke@435 | 736 | |
duke@435 | 737 | void NullCheckEliminator::handle_AccessField(AccessField* x) { |
duke@435 | 738 | if (x->is_static()) { |
duke@435 | 739 | if (x->as_LoadField() != NULL) { |
duke@435 | 740 | // If the field is a non-null static final object field (as is |
duke@435 | 741 | // often the case for sun.misc.Unsafe), put this LoadField into |
duke@435 | 742 | // the non-null map |
duke@435 | 743 | ciField* field = x->field(); |
duke@435 | 744 | if (field->is_constant()) { |
duke@435 | 745 | ciConstant field_val = field->constant_value(); |
duke@435 | 746 | BasicType field_type = field_val.basic_type(); |
duke@435 | 747 | if (field_type == T_OBJECT || field_type == T_ARRAY) { |
duke@435 | 748 | ciObject* obj_val = field_val.as_object(); |
duke@435 | 749 | if (!obj_val->is_null_object()) { |
duke@435 | 750 | if (PrintNullCheckElimination) { |
duke@435 | 751 | tty->print_cr("AccessField %d proven non-null by static final non-null oop check", |
duke@435 | 752 | x->id()); |
duke@435 | 753 | } |
duke@435 | 754 | set_put(x); |
duke@435 | 755 | } |
duke@435 | 756 | } |
duke@435 | 757 | } |
duke@435 | 758 | } |
duke@435 | 759 | // Be conservative |
duke@435 | 760 | clear_last_explicit_null_check(); |
duke@435 | 761 | return; |
duke@435 | 762 | } |
duke@435 | 763 | |
duke@435 | 764 | Value obj = x->obj(); |
duke@435 | 765 | if (set_contains(obj)) { |
duke@435 | 766 | // Value is non-null => update AccessField |
duke@435 | 767 | if (last_explicit_null_check_obj() == obj && !x->needs_patching()) { |
duke@435 | 768 | x->set_explicit_null_check(consume_last_explicit_null_check()); |
duke@435 | 769 | x->set_needs_null_check(true); |
duke@435 | 770 | if (PrintNullCheckElimination) { |
duke@435 | 771 | tty->print_cr("Folded NullCheck %d into AccessField %d's null check for value %d", |
duke@435 | 772 | x->explicit_null_check()->id(), x->id(), obj->id()); |
duke@435 | 773 | } |
duke@435 | 774 | } else { |
duke@435 | 775 | x->set_explicit_null_check(NULL); |
duke@435 | 776 | x->set_needs_null_check(false); |
duke@435 | 777 | if (PrintNullCheckElimination) { |
duke@435 | 778 | tty->print_cr("Eliminated AccessField %d's null check for value %d", x->id(), obj->id()); |
duke@435 | 779 | } |
duke@435 | 780 | } |
duke@435 | 781 | } else { |
duke@435 | 782 | set_put(obj); |
duke@435 | 783 | if (PrintNullCheckElimination) { |
duke@435 | 784 | tty->print_cr("AccessField %d of value %d proves value to be non-null", x->id(), obj->id()); |
duke@435 | 785 | } |
duke@435 | 786 | // Ensure previous passes do not cause wrong state |
duke@435 | 787 | x->set_needs_null_check(true); |
duke@435 | 788 | x->set_explicit_null_check(NULL); |
duke@435 | 789 | } |
duke@435 | 790 | clear_last_explicit_null_check(); |
duke@435 | 791 | } |
duke@435 | 792 | |
duke@435 | 793 | |
duke@435 | 794 | void NullCheckEliminator::handle_ArrayLength(ArrayLength* x) { |
duke@435 | 795 | Value array = x->array(); |
duke@435 | 796 | if (set_contains(array)) { |
duke@435 | 797 | // Value is non-null => update AccessArray |
duke@435 | 798 | if (last_explicit_null_check_obj() == array) { |
duke@435 | 799 | x->set_explicit_null_check(consume_last_explicit_null_check()); |
duke@435 | 800 | x->set_needs_null_check(true); |
duke@435 | 801 | if (PrintNullCheckElimination) { |
duke@435 | 802 | tty->print_cr("Folded NullCheck %d into ArrayLength %d's null check for value %d", |
duke@435 | 803 | x->explicit_null_check()->id(), x->id(), array->id()); |
duke@435 | 804 | } |
duke@435 | 805 | } else { |
duke@435 | 806 | x->set_explicit_null_check(NULL); |
duke@435 | 807 | x->set_needs_null_check(false); |
duke@435 | 808 | if (PrintNullCheckElimination) { |
duke@435 | 809 | tty->print_cr("Eliminated ArrayLength %d's null check for value %d", x->id(), array->id()); |
duke@435 | 810 | } |
duke@435 | 811 | } |
duke@435 | 812 | } else { |
duke@435 | 813 | set_put(array); |
duke@435 | 814 | if (PrintNullCheckElimination) { |
duke@435 | 815 | tty->print_cr("ArrayLength %d of value %d proves value to be non-null", x->id(), array->id()); |
duke@435 | 816 | } |
duke@435 | 817 | // Ensure previous passes do not cause wrong state |
duke@435 | 818 | x->set_needs_null_check(true); |
duke@435 | 819 | x->set_explicit_null_check(NULL); |
duke@435 | 820 | } |
duke@435 | 821 | clear_last_explicit_null_check(); |
duke@435 | 822 | } |
duke@435 | 823 | |
duke@435 | 824 | |
duke@435 | 825 | void NullCheckEliminator::handle_LoadIndexed(LoadIndexed* x) { |
duke@435 | 826 | Value array = x->array(); |
duke@435 | 827 | if (set_contains(array)) { |
duke@435 | 828 | // Value is non-null => update AccessArray |
duke@435 | 829 | if (last_explicit_null_check_obj() == array) { |
duke@435 | 830 | x->set_explicit_null_check(consume_last_explicit_null_check()); |
duke@435 | 831 | x->set_needs_null_check(true); |
duke@435 | 832 | if (PrintNullCheckElimination) { |
duke@435 | 833 | tty->print_cr("Folded NullCheck %d into LoadIndexed %d's null check for value %d", |
duke@435 | 834 | x->explicit_null_check()->id(), x->id(), array->id()); |
duke@435 | 835 | } |
duke@435 | 836 | } else { |
duke@435 | 837 | x->set_explicit_null_check(NULL); |
duke@435 | 838 | x->set_needs_null_check(false); |
duke@435 | 839 | if (PrintNullCheckElimination) { |
duke@435 | 840 | tty->print_cr("Eliminated LoadIndexed %d's null check for value %d", x->id(), array->id()); |
duke@435 | 841 | } |
duke@435 | 842 | } |
duke@435 | 843 | } else { |
duke@435 | 844 | set_put(array); |
duke@435 | 845 | if (PrintNullCheckElimination) { |
duke@435 | 846 | tty->print_cr("LoadIndexed %d of value %d proves value to be non-null", x->id(), array->id()); |
duke@435 | 847 | } |
duke@435 | 848 | // Ensure previous passes do not cause wrong state |
duke@435 | 849 | x->set_needs_null_check(true); |
duke@435 | 850 | x->set_explicit_null_check(NULL); |
duke@435 | 851 | } |
duke@435 | 852 | clear_last_explicit_null_check(); |
duke@435 | 853 | } |
duke@435 | 854 | |
duke@435 | 855 | |
duke@435 | 856 | void NullCheckEliminator::handle_StoreIndexed(StoreIndexed* x) { |
duke@435 | 857 | Value array = x->array(); |
duke@435 | 858 | if (set_contains(array)) { |
duke@435 | 859 | // Value is non-null => update AccessArray |
duke@435 | 860 | if (PrintNullCheckElimination) { |
duke@435 | 861 | tty->print_cr("Eliminated StoreIndexed %d's null check for value %d", x->id(), array->id()); |
duke@435 | 862 | } |
duke@435 | 863 | x->set_needs_null_check(false); |
duke@435 | 864 | } else { |
duke@435 | 865 | set_put(array); |
duke@435 | 866 | if (PrintNullCheckElimination) { |
duke@435 | 867 | tty->print_cr("StoreIndexed %d of value %d proves value to be non-null", x->id(), array->id()); |
duke@435 | 868 | } |
duke@435 | 869 | // Ensure previous passes do not cause wrong state |
duke@435 | 870 | x->set_needs_null_check(true); |
duke@435 | 871 | } |
duke@435 | 872 | clear_last_explicit_null_check(); |
duke@435 | 873 | } |
duke@435 | 874 | |
duke@435 | 875 | |
duke@435 | 876 | void NullCheckEliminator::handle_NullCheck(NullCheck* x) { |
duke@435 | 877 | Value obj = x->obj(); |
duke@435 | 878 | if (set_contains(obj)) { |
duke@435 | 879 | // Already proven to be non-null => this NullCheck is useless |
duke@435 | 880 | if (PrintNullCheckElimination) { |
duke@435 | 881 | tty->print_cr("Eliminated NullCheck %d for value %d", x->id(), obj->id()); |
duke@435 | 882 | } |
duke@435 | 883 | // Don't unpin since that may shrink obj's live range and make it unavailable for debug info. |
duke@435 | 884 | // The code generator won't emit LIR for a NullCheck that cannot trap. |
duke@435 | 885 | x->set_can_trap(false); |
duke@435 | 886 | } else { |
duke@435 | 887 | // May be null => add to map and set last explicit NullCheck |
duke@435 | 888 | x->set_can_trap(true); |
duke@435 | 889 | // make sure it's pinned if it can trap |
duke@435 | 890 | x->pin(Instruction::PinExplicitNullCheck); |
duke@435 | 891 | set_put(obj); |
duke@435 | 892 | set_last_explicit_null_check(x); |
duke@435 | 893 | if (PrintNullCheckElimination) { |
duke@435 | 894 | tty->print_cr("NullCheck %d of value %d proves value to be non-null", x->id(), obj->id()); |
duke@435 | 895 | } |
duke@435 | 896 | } |
duke@435 | 897 | } |
duke@435 | 898 | |
duke@435 | 899 | |
duke@435 | 900 | void NullCheckEliminator::handle_Invoke(Invoke* x) { |
duke@435 | 901 | if (!x->has_receiver()) { |
duke@435 | 902 | // Be conservative |
duke@435 | 903 | clear_last_explicit_null_check(); |
duke@435 | 904 | return; |
duke@435 | 905 | } |
duke@435 | 906 | |
duke@435 | 907 | Value recv = x->receiver(); |
duke@435 | 908 | if (!set_contains(recv)) { |
duke@435 | 909 | set_put(recv); |
duke@435 | 910 | if (PrintNullCheckElimination) { |
duke@435 | 911 | tty->print_cr("Invoke %d of value %d proves value to be non-null", x->id(), recv->id()); |
duke@435 | 912 | } |
duke@435 | 913 | } |
duke@435 | 914 | clear_last_explicit_null_check(); |
duke@435 | 915 | } |
duke@435 | 916 | |
duke@435 | 917 | |
duke@435 | 918 | void NullCheckEliminator::handle_NewInstance(NewInstance* x) { |
duke@435 | 919 | set_put(x); |
duke@435 | 920 | if (PrintNullCheckElimination) { |
duke@435 | 921 | tty->print_cr("NewInstance %d is non-null", x->id()); |
duke@435 | 922 | } |
duke@435 | 923 | } |
duke@435 | 924 | |
duke@435 | 925 | |
duke@435 | 926 | void NullCheckEliminator::handle_NewArray(NewArray* x) { |
duke@435 | 927 | set_put(x); |
duke@435 | 928 | if (PrintNullCheckElimination) { |
duke@435 | 929 | tty->print_cr("NewArray %d is non-null", x->id()); |
duke@435 | 930 | } |
duke@435 | 931 | } |
duke@435 | 932 | |
duke@435 | 933 | |
duke@435 | 934 | void NullCheckEliminator::handle_ExceptionObject(ExceptionObject* x) { |
duke@435 | 935 | set_put(x); |
duke@435 | 936 | if (PrintNullCheckElimination) { |
duke@435 | 937 | tty->print_cr("ExceptionObject %d is non-null", x->id()); |
duke@435 | 938 | } |
duke@435 | 939 | } |
duke@435 | 940 | |
duke@435 | 941 | |
duke@435 | 942 | void NullCheckEliminator::handle_AccessMonitor(AccessMonitor* x) { |
duke@435 | 943 | Value obj = x->obj(); |
duke@435 | 944 | if (set_contains(obj)) { |
duke@435 | 945 | // Value is non-null => update AccessMonitor |
duke@435 | 946 | if (PrintNullCheckElimination) { |
duke@435 | 947 | tty->print_cr("Eliminated AccessMonitor %d's null check for value %d", x->id(), obj->id()); |
duke@435 | 948 | } |
duke@435 | 949 | x->set_needs_null_check(false); |
duke@435 | 950 | } else { |
duke@435 | 951 | set_put(obj); |
duke@435 | 952 | if (PrintNullCheckElimination) { |
duke@435 | 953 | tty->print_cr("AccessMonitor %d of value %d proves value to be non-null", x->id(), obj->id()); |
duke@435 | 954 | } |
duke@435 | 955 | // Ensure previous passes do not cause wrong state |
duke@435 | 956 | x->set_needs_null_check(true); |
duke@435 | 957 | } |
duke@435 | 958 | clear_last_explicit_null_check(); |
duke@435 | 959 | } |
duke@435 | 960 | |
duke@435 | 961 | |
duke@435 | 962 | void NullCheckEliminator::handle_Intrinsic(Intrinsic* x) { |
duke@435 | 963 | if (!x->has_receiver()) { |
duke@435 | 964 | // Be conservative |
duke@435 | 965 | clear_last_explicit_null_check(); |
duke@435 | 966 | return; |
duke@435 | 967 | } |
duke@435 | 968 | |
duke@435 | 969 | Value recv = x->receiver(); |
duke@435 | 970 | if (set_contains(recv)) { |
duke@435 | 971 | // Value is non-null => update Intrinsic |
duke@435 | 972 | if (PrintNullCheckElimination) { |
duke@435 | 973 | tty->print_cr("Eliminated Intrinsic %d's null check for value %d", x->id(), recv->id()); |
duke@435 | 974 | } |
duke@435 | 975 | x->set_needs_null_check(false); |
duke@435 | 976 | } else { |
duke@435 | 977 | set_put(recv); |
duke@435 | 978 | if (PrintNullCheckElimination) { |
duke@435 | 979 | tty->print_cr("Intrinsic %d of value %d proves value to be non-null", x->id(), recv->id()); |
duke@435 | 980 | } |
duke@435 | 981 | // Ensure previous passes do not cause wrong state |
duke@435 | 982 | x->set_needs_null_check(true); |
duke@435 | 983 | } |
duke@435 | 984 | clear_last_explicit_null_check(); |
duke@435 | 985 | } |
duke@435 | 986 | |
duke@435 | 987 | |
duke@435 | 988 | void NullCheckEliminator::handle_Phi(Phi* x) { |
duke@435 | 989 | int i; |
duke@435 | 990 | bool all_non_null = true; |
duke@435 | 991 | if (x->is_illegal()) { |
duke@435 | 992 | all_non_null = false; |
duke@435 | 993 | } else { |
duke@435 | 994 | for (i = 0; i < x->operand_count(); i++) { |
duke@435 | 995 | Value input = x->operand_at(i); |
duke@435 | 996 | if (!set_contains(input)) { |
duke@435 | 997 | all_non_null = false; |
duke@435 | 998 | } |
duke@435 | 999 | } |
duke@435 | 1000 | } |
duke@435 | 1001 | |
duke@435 | 1002 | if (all_non_null) { |
duke@435 | 1003 | // Value is non-null => update Phi |
duke@435 | 1004 | if (PrintNullCheckElimination) { |
duke@435 | 1005 | tty->print_cr("Eliminated Phi %d's null check for phifun because all inputs are non-null", x->id()); |
duke@435 | 1006 | } |
duke@435 | 1007 | x->set_needs_null_check(false); |
duke@435 | 1008 | } else if (set_contains(x)) { |
duke@435 | 1009 | set_remove(x); |
duke@435 | 1010 | } |
duke@435 | 1011 | } |
duke@435 | 1012 | |
duke@435 | 1013 | |
duke@435 | 1014 | void Optimizer::eliminate_null_checks() { |
duke@435 | 1015 | ResourceMark rm; |
duke@435 | 1016 | |
duke@435 | 1017 | NullCheckEliminator nce(this); |
duke@435 | 1018 | |
duke@435 | 1019 | if (PrintNullCheckElimination) { |
duke@435 | 1020 | tty->print_cr("Starting null check elimination for method %s::%s%s", |
duke@435 | 1021 | ir()->method()->holder()->name()->as_utf8(), |
duke@435 | 1022 | ir()->method()->name()->as_utf8(), |
duke@435 | 1023 | ir()->method()->signature()->as_symbol()->as_utf8()); |
duke@435 | 1024 | } |
duke@435 | 1025 | |
duke@435 | 1026 | // Apply to graph |
duke@435 | 1027 | nce.iterate(ir()->start()); |
duke@435 | 1028 | |
duke@435 | 1029 | // walk over the graph looking for exception |
duke@435 | 1030 | // handlers and iterate over them as well |
duke@435 | 1031 | int nblocks = BlockBegin::number_of_blocks(); |
duke@435 | 1032 | BlockList blocks(nblocks); |
duke@435 | 1033 | boolArray visited_block(nblocks, false); |
duke@435 | 1034 | |
duke@435 | 1035 | blocks.push(ir()->start()); |
duke@435 | 1036 | visited_block[ir()->start()->block_id()] = true; |
duke@435 | 1037 | for (int i = 0; i < blocks.length(); i++) { |
duke@435 | 1038 | BlockBegin* b = blocks[i]; |
duke@435 | 1039 | // exception handlers need to be treated as additional roots |
duke@435 | 1040 | for (int e = b->number_of_exception_handlers(); e-- > 0; ) { |
duke@435 | 1041 | BlockBegin* excp = b->exception_handler_at(e); |
duke@435 | 1042 | int id = excp->block_id(); |
duke@435 | 1043 | if (!visited_block[id]) { |
duke@435 | 1044 | blocks.push(excp); |
duke@435 | 1045 | visited_block[id] = true; |
duke@435 | 1046 | nce.iterate(excp); |
duke@435 | 1047 | } |
duke@435 | 1048 | } |
duke@435 | 1049 | // traverse successors |
duke@435 | 1050 | BlockEnd *end = b->end(); |
duke@435 | 1051 | for (int s = end->number_of_sux(); s-- > 0; ) { |
duke@435 | 1052 | BlockBegin* next = end->sux_at(s); |
duke@435 | 1053 | int id = next->block_id(); |
duke@435 | 1054 | if (!visited_block[id]) { |
duke@435 | 1055 | blocks.push(next); |
duke@435 | 1056 | visited_block[id] = true; |
duke@435 | 1057 | } |
duke@435 | 1058 | } |
duke@435 | 1059 | } |
duke@435 | 1060 | |
duke@435 | 1061 | |
duke@435 | 1062 | if (PrintNullCheckElimination) { |
duke@435 | 1063 | tty->print_cr("Done with null check elimination for method %s::%s%s", |
duke@435 | 1064 | ir()->method()->holder()->name()->as_utf8(), |
duke@435 | 1065 | ir()->method()->name()->as_utf8(), |
duke@435 | 1066 | ir()->method()->signature()->as_symbol()->as_utf8()); |
duke@435 | 1067 | } |
duke@435 | 1068 | } |