1 /*
2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_Canonicalizer.hpp"
27 #include "c1/c1_InstructionPrinter.hpp"
28 #include "c1/c1_ValueStack.hpp"
29 #include "ci/ciArray.hpp"
30 #include "runtime/sharedRuntime.hpp"
31
32
33 class PrintValueVisitor: public ValueVisitor {
34 void visit(Value* vp) {
35 (*vp)->print_line();
36 }
37 };
38
39 void Canonicalizer::set_canonical(Value x) {
40 assert(x != NULL, "value must exist");
41 // Note: we can not currently substitute root nodes which show up in
42 // the instruction stream (because the instruction list is embedded
43 // in the instructions).
44 if (canonical() != x) {
45 #ifndef PRODUCT
46 if (!x->has_printable_bci()) {
47 x->set_printable_bci(bci());
48 }
49 #endif
50 if (PrintCanonicalization) {
51 PrintValueVisitor do_print_value;
52 canonical()->input_values_do(&do_print_value);
53 canonical()->print_line();
54 tty->print_cr("canonicalized to:");
55 x->input_values_do(&do_print_value);
56 x->print_line();
57 tty->cr();
58 }
59 assert(_canonical->type()->tag() == x->type()->tag(), "types must match");
60 _canonical = x;
61 }
62 }
63
64
65 void Canonicalizer::move_const_to_right(Op2* x) {
66 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands();
67 }
68
69
70 void Canonicalizer::do_Op2(Op2* x) {
71 if (x->x() == x->y()) {
72 switch (x->op()) {
73 case Bytecodes::_isub: set_constant(0); return;
74 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
75 case Bytecodes::_iand: // fall through
76 case Bytecodes::_land: // fall through
77 case Bytecodes::_ior : // fall through
78 case Bytecodes::_lor : set_canonical(x->x()); return;
79 case Bytecodes::_ixor: set_constant(0); return;
80 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
81 default : break;
82 }
83 }
84
85 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
86 // do constant folding for selected operations
87 switch (x->type()->tag()) {
88 case intTag:
89 { jint a = x->x()->type()->as_IntConstant()->value();
90 jint b = x->y()->type()->as_IntConstant()->value();
91 switch (x->op()) {
92 case Bytecodes::_iadd: set_constant(a + b); return;
93 case Bytecodes::_isub: set_constant(a - b); return;
94 case Bytecodes::_imul: set_constant(a * b); return;
95 case Bytecodes::_idiv:
96 if (b != 0) {
97 if (a == min_jint && b == -1) {
98 set_constant(min_jint);
99 } else {
100 set_constant(a / b);
101 }
102 return;
103 }
104 break;
105 case Bytecodes::_irem:
106 if (b != 0) {
107 if (a == min_jint && b == -1) {
108 set_constant(0);
109 } else {
110 set_constant(a % b);
111 }
112 return;
113 }
114 break;
115 case Bytecodes::_iand: set_constant(a & b); return;
116 case Bytecodes::_ior : set_constant(a | b); return;
117 case Bytecodes::_ixor: set_constant(a ^ b); return;
118 default : break;
119 }
120 }
121 break;
122 case longTag:
123 { jlong a = x->x()->type()->as_LongConstant()->value();
124 jlong b = x->y()->type()->as_LongConstant()->value();
125 switch (x->op()) {
126 case Bytecodes::_ladd: set_constant(a + b); return;
127 case Bytecodes::_lsub: set_constant(a - b); return;
128 case Bytecodes::_lmul: set_constant(a * b); return;
129 case Bytecodes::_ldiv:
130 if (b != 0) {
131 set_constant(SharedRuntime::ldiv(b, a));
132 return;
133 }
134 break;
135 case Bytecodes::_lrem:
136 if (b != 0) {
137 set_constant(SharedRuntime::lrem(b, a));
138 return;
139 }
140 break;
141 case Bytecodes::_land: set_constant(a & b); return;
142 case Bytecodes::_lor : set_constant(a | b); return;
143 case Bytecodes::_lxor: set_constant(a ^ b); return;
144 default : break;
145 }
146 }
147 break;
148 default:
149 // other cases not implemented (must be extremely careful with floats & doubles!)
150 break;
151 }
152 }
153 // make sure constant is on the right side, if any
154 move_const_to_right(x);
155
156 if (x->y()->type()->is_constant()) {
157 // do constant folding for selected operations
158 switch (x->type()->tag()) {
159 case intTag:
160 if (x->y()->type()->as_IntConstant()->value() == 0) {
161 switch (x->op()) {
162 case Bytecodes::_iadd: set_canonical(x->x()); return;
163 case Bytecodes::_isub: set_canonical(x->x()); return;
164 case Bytecodes::_imul: set_constant(0); return;
165 // Note: for div and rem, make sure that C semantics
166 // corresponds to Java semantics!
167 case Bytecodes::_iand: set_constant(0); return;
168 case Bytecodes::_ior : set_canonical(x->x()); return;
169 default : break;
170 }
171 }
172 break;
173 case longTag:
174 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
175 switch (x->op()) {
176 case Bytecodes::_ladd: set_canonical(x->x()); return;
177 case Bytecodes::_lsub: set_canonical(x->x()); return;
178 case Bytecodes::_lmul: set_constant((jlong)0); return;
179 // Note: for div and rem, make sure that C semantics
180 // corresponds to Java semantics!
181 case Bytecodes::_land: set_constant((jlong)0); return;
182 case Bytecodes::_lor : set_canonical(x->x()); return;
183 default : break;
184 }
185 }
186 break;
187 default:
188 break;
189 }
190 }
191 }
192
193
194 void Canonicalizer::do_Phi (Phi* x) {}
195 void Canonicalizer::do_Constant (Constant* x) {}
196 void Canonicalizer::do_Local (Local* x) {}
197 void Canonicalizer::do_LoadField (LoadField* x) {}
198
199 // checks if v is in the block that is currently processed by
200 // GraphBuilder. This is the only block that has not BlockEnd yet.
201 static bool in_current_block(Value v) {
202 int max_distance = 4;
203 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
204 v = v->next();
205 max_distance--;
206 }
207 return v == NULL;
208 }
209
210 void Canonicalizer::do_StoreField (StoreField* x) {
211 // If a value is going to be stored into a field or array some of
212 // the conversions emitted by javac are unneeded because the fields
213 // are packed to their natural size.
214 Convert* conv = x->value()->as_Convert();
215 if (conv) {
216 Value value = NULL;
217 BasicType type = x->field()->type()->basic_type();
218 switch (conv->op()) {
219 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
220 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
221 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
222 default : break;
223 }
224 // limit this optimization to current block
225 if (value != NULL && in_current_block(conv)) {
226 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
227 x->state_before(), x->needs_patching()));
228 return;
229 }
230 }
231
232 }
233
234 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
235 NewArray* na;
236 Constant* ct;
237 LoadField* lf;
238
239 if ((na = x->array()->as_NewArray()) != NULL) {
240 // New arrays might have the known length.
241 // Do not use the Constant itself, but create a new Constant
242 // with same value Otherwise a Constant is live over multiple
243 // blocks without being registered in a state array.
244 Constant* length;
245 if (na->length() != NULL &&
246 (length = na->length()->as_Constant()) != NULL) {
247 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
248 set_constant(length->type()->as_IntConstant()->value());
249 }
250
251 } else if ((ct = x->array()->as_Constant()) != NULL) {
252 // Constant arrays have constant lengths.
253 ArrayConstant* cnst = ct->type()->as_ArrayConstant();
254 if (cnst != NULL) {
255 set_constant(cnst->value()->length());
256 }
257
258 } else if ((lf = x->array()->as_LoadField()) != NULL) {
259 ciField* field = lf->field();
260 if (field->is_static_constant()) {
261 // Constant field loads are usually folded during parsing.
262 // But it doesn't happen with PatchALot, ScavengeRootsInCode < 2, or when
263 // holder class is being initialized during parsing (for static fields).
264 ciObject* c = field->constant_value().as_object();
265 if (!c->is_null_object()) {
266 set_constant(c->as_array()->length());
267 }
268 }
269 }
270 }
271
272 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {
273 StableArrayConstant* array = x->array()->type()->as_StableArrayConstant();
274 IntConstant* index = x->index()->type()->as_IntConstant();
275
276 assert(array == NULL || FoldStableValues, "not enabled");
277
278 // Constant fold loads from stable arrays.
279 if (!x->mismatched() && array != NULL && index != NULL) {
280 jint idx = index->value();
281 if (idx < 0 || idx >= array->value()->length()) {
282 // Leave the load as is. The range check will handle it.
283 return;
284 }
285
286 ciConstant field_val = array->value()->element_value(idx);
287 if (!field_val.is_null_or_zero()) {
288 jint dimension = array->dimension();
289 assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info");
290 ValueType* value = NULL;
291 if (dimension > 1) {
292 // Preserve information about the dimension for the element.
293 assert(field_val.as_object()->is_array(), "not an array");
294 value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1);
295 } else {
296 assert(dimension == 1, "sanity");
297 value = as_ValueType(field_val);
298 }
299 set_canonical(new Constant(value));
300 }
301 }
302 }
303
304 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
305 // If a value is going to be stored into a field or array some of
306 // the conversions emitted by javac are unneeded because the fields
307 // are packed to their natural size.
308 Convert* conv = x->value()->as_Convert();
309 if (conv) {
310 Value value = NULL;
311 BasicType type = x->elt_type();
312 switch (conv->op()) {
313 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
314 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
315 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
316 default : break;
317 }
318 // limit this optimization to current block
319 if (value != NULL && in_current_block(conv)) {
320 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
321 x->elt_type(), value, x->state_before(),
322 x->check_boolean()));
323 return;
324 }
325 }
326 }
327
328
329 void Canonicalizer::do_NegateOp(NegateOp* x) {
330 ValueType* t = x->x()->type();
331 if (t->is_constant()) {
332 switch (t->tag()) {
333 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
334 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
335 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
336 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
337 default : ShouldNotReachHere();
338 }
339 }
340 }
341
342
343 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
344
345
346 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
347 ValueType* t = x->x()->type();
348 ValueType* t2 = x->y()->type();
349 if (t->is_constant()) {
350 switch (t->tag()) {
351 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
352 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
353 default : ShouldNotReachHere();
354 }
355 if (t2->is_constant()) {
356 if (t->tag() == intTag) {
357 int value = t->as_IntConstant()->value();
358 int shift = t2->as_IntConstant()->value() & 31;
359 jint mask = ~(~0 << (32 - shift));
360 if (shift == 0) mask = ~0;
361 switch (x->op()) {
362 case Bytecodes::_ishl: set_constant(value << shift); return;
363 case Bytecodes::_ishr: set_constant(value >> shift); return;
364 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
365 default: break;
366 }
367 } else if (t->tag() == longTag) {
368 jlong value = t->as_LongConstant()->value();
369 int shift = t2->as_IntConstant()->value() & 63;
370 jlong mask = ~(~jlong_cast(0) << (64 - shift));
371 if (shift == 0) mask = ~jlong_cast(0);
372 switch (x->op()) {
373 case Bytecodes::_lshl: set_constant(value << shift); return;
374 case Bytecodes::_lshr: set_constant(value >> shift); return;
375 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
376 default: break;
377 }
378 }
379 }
380 }
381 if (t2->is_constant()) {
382 switch (t2->tag()) {
383 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
384 case longTag : if (t2->as_LongConstant()->value() == (jlong)0) set_canonical(x->x()); return;
385 default : ShouldNotReachHere();
386 }
387 }
388 }
389
390
391 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
392 void Canonicalizer::do_CompareOp (CompareOp* x) {
393 if (x->x() == x->y()) {
394 switch (x->x()->type()->tag()) {
395 case longTag: set_constant(0); break;
396 case floatTag: {
397 FloatConstant* fc = x->x()->type()->as_FloatConstant();
398 if (fc) {
399 if (g_isnan(fc->value())) {
400 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
401 } else {
402 set_constant(0);
403 }
404 }
405 break;
406 }
407 case doubleTag: {
408 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
409 if (dc) {
410 if (g_isnan(dc->value())) {
411 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
412 } else {
413 set_constant(0);
414 }
415 }
416 break;
417 }
418 default:
419 break;
420 }
421 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
422 switch (x->x()->type()->tag()) {
423 case longTag: {
424 jlong vx = x->x()->type()->as_LongConstant()->value();
425 jlong vy = x->y()->type()->as_LongConstant()->value();
426 if (vx == vy)
427 set_constant(0);
428 else if (vx < vy)
429 set_constant(-1);
430 else
431 set_constant(1);
432 break;
433 }
434
435 case floatTag: {
436 float vx = x->x()->type()->as_FloatConstant()->value();
437 float vy = x->y()->type()->as_FloatConstant()->value();
438 if (g_isnan(vx) || g_isnan(vy))
439 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
440 else if (vx == vy)
441 set_constant(0);
442 else if (vx < vy)
443 set_constant(-1);
444 else
445 set_constant(1);
446 break;
447 }
448
449 case doubleTag: {
450 double vx = x->x()->type()->as_DoubleConstant()->value();
451 double vy = x->y()->type()->as_DoubleConstant()->value();
452 if (g_isnan(vx) || g_isnan(vy))
453 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
454 else if (vx == vy)
455 set_constant(0);
456 else if (vx < vy)
457 set_constant(-1);
458 else
459 set_constant(1);
460 break;
461 }
462
463 default:
464 break;
465 }
466 }
467 }
468
469
470 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
471
472 void Canonicalizer::do_IfOp(IfOp* x) {
473 // Caution: do not use do_Op2(x) here for now since
474 // we map the condition to the op for now!
475 move_const_to_right(x);
476 }
477
478
479 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
480 switch (x->id()) {
481 case vmIntrinsics::_floatToRawIntBits : {
482 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
483 if (c != NULL) {
484 JavaValue v;
485 v.set_jfloat(c->value());
486 set_constant(v.get_jint());
487 }
488 break;
489 }
490 case vmIntrinsics::_intBitsToFloat : {
491 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
492 if (c != NULL) {
493 JavaValue v;
494 v.set_jint(c->value());
495 set_constant(v.get_jfloat());
496 }
497 break;
498 }
499 case vmIntrinsics::_doubleToRawLongBits : {
500 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
501 if (c != NULL) {
502 JavaValue v;
503 v.set_jdouble(c->value());
504 set_constant(v.get_jlong());
505 }
506 break;
507 }
508 case vmIntrinsics::_longBitsToDouble : {
509 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
510 if (c != NULL) {
511 JavaValue v;
512 v.set_jlong(c->value());
513 set_constant(v.get_jdouble());
514 }
515 break;
516 }
517 case vmIntrinsics::_isInstance : {
518 assert(x->number_of_arguments() == 2, "wrong type");
519
520 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
521 if (c != NULL && !c->value()->is_null_object()) {
522 // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors
523 ciType* t = c->value()->java_mirror_type();
524 if (t->is_klass()) {
525 // substitute cls.isInstance(obj) of a constant Class into
526 // an InstantOf instruction
527 InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before());
528 set_canonical(i);
529 // and try to canonicalize even further
530 do_InstanceOf(i);
531 } else {
532 assert(t->is_primitive_type(), "should be a primitive type");
533 // cls.isInstance(obj) always returns false for primitive classes
534 set_constant(0);
535 }
536 }
537 break;
538 }
539 case vmIntrinsics::_isPrimitive : {
540 assert(x->number_of_arguments() == 1, "wrong type");
541
542 // Class.isPrimitive is known on constant classes:
543 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
544 if (c != NULL && !c->value()->is_null_object()) {
545 ciType* t = c->value()->java_mirror_type();
546 set_constant(t->is_primitive_type());
547 }
548 break;
549 }
550 default:
551 break;
552 }
553 }
554
555 void Canonicalizer::do_Convert (Convert* x) {
556 if (x->value()->type()->is_constant()) {
557 switch (x->op()) {
558 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
559 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
560 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
561 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
562 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
563 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
564 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
565 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
566 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
567 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
568 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
569 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
570 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
571 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
572 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
573 default:
574 ShouldNotReachHere();
575 }
576 }
577
578 Value value = x->value();
579 BasicType type = T_ILLEGAL;
580 LoadField* lf = value->as_LoadField();
581 if (lf) {
582 type = lf->field_type();
583 } else {
584 LoadIndexed* li = value->as_LoadIndexed();
585 if (li) {
586 type = li->elt_type();
587 } else {
588 Convert* conv = value->as_Convert();
589 if (conv) {
590 switch (conv->op()) {
591 case Bytecodes::_i2b: type = T_BYTE; break;
592 case Bytecodes::_i2s: type = T_SHORT; break;
593 case Bytecodes::_i2c: type = T_CHAR; break;
594 default : break;
595 }
596 }
597 }
598 }
599 if (type != T_ILLEGAL) {
600 switch (x->op()) {
601 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
602 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
603 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
604 default : break;
605 }
606 } else {
607 Op2* op2 = x->value()->as_Op2();
608 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
609 jint safebits = 0;
610 jint mask = op2->y()->type()->as_IntConstant()->value();
611 switch (x->op()) {
612 case Bytecodes::_i2b: safebits = 0x7f; break;
613 case Bytecodes::_i2s: safebits = 0x7fff; break;
614 case Bytecodes::_i2c: safebits = 0xffff; break;
615 default : break;
616 }
617 // When casting a masked integer to a smaller signed type, if
618 // the mask doesn't include the sign bit the cast isn't needed.
619 if (safebits && (mask & ~safebits) == 0) {
620 set_canonical(x->value());
621 }
622 }
623 }
624
625 }
626
627 void Canonicalizer::do_NullCheck (NullCheck* x) {
628 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
629 set_canonical(x->obj());
630 } else {
631 Constant* con = x->obj()->as_Constant();
632 if (con) {
633 ObjectType* c = con->type()->as_ObjectType();
634 if (c && c->is_loaded()) {
635 ObjectConstant* oc = c->as_ObjectConstant();
636 if (!oc || !oc->value()->is_null_object()) {
637 set_canonical(con);
638 }
639 }
640 }
641 }
642 }
643
644 void Canonicalizer::do_TypeCast (TypeCast* x) {}
645 void Canonicalizer::do_Invoke (Invoke* x) {}
646 void Canonicalizer::do_NewInstance (NewInstance* x) {}
647 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
648 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
649 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
650 void Canonicalizer::do_CheckCast (CheckCast* x) {
651 if (x->klass()->is_loaded()) {
652 Value obj = x->obj();
653 ciType* klass = obj->exact_type();
654 if (klass == NULL) klass = obj->declared_type();
655 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
656 set_canonical(obj);
657 return;
658 }
659 // checkcast of null returns null
660 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
661 set_canonical(obj);
662 }
663 }
664 }
665 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
666 if (x->klass()->is_loaded()) {
667 Value obj = x->obj();
668 ciType* exact = obj->exact_type();
669 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
670 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
671 return;
672 }
673 // instanceof null returns false
674 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
675 set_constant(0);
676 }
677 }
678
679 }
680 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
681 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
682 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
683 void Canonicalizer::do_Goto (Goto* x) {}
684
685
686 static bool is_true(jlong x, If::Condition cond, jlong y) {
687 switch (cond) {
688 case If::eql: return x == y;
689 case If::neq: return x != y;
690 case If::lss: return x < y;
691 case If::leq: return x <= y;
692 case If::gtr: return x > y;
693 case If::geq: return x >= y;
694 default:
695 ShouldNotReachHere();
696 return false;
697 }
698 }
699
700 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
701 // An Instruction with multiple successors, x, is replaced by a Goto
702 // to a single successor, sux. Is a safepoint check needed = was the
703 // instruction being replaced a safepoint and the single remaining
704 // successor a back branch?
705 return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
706 }
707
708 void Canonicalizer::do_If(If* x) {
709 // move const to right
710 if (x->x()->type()->is_constant()) x->swap_operands();
711 // simplify
712 const Value l = x->x(); ValueType* lt = l->type();
713 const Value r = x->y(); ValueType* rt = r->type();
714
715 if (l == r && !lt->is_float_kind()) {
716 // pattern: If (a cond a) => simplify to Goto
717 BlockBegin* sux = NULL;
718 switch (x->cond()) {
719 case If::eql: sux = x->sux_for(true); break;
720 case If::neq: sux = x->sux_for(false); break;
721 case If::lss: sux = x->sux_for(false); break;
722 case If::leq: sux = x->sux_for(true); break;
723 case If::gtr: sux = x->sux_for(false); break;
724 case If::geq: sux = x->sux_for(true); break;
725 default: ShouldNotReachHere();
726 }
727 // If is a safepoint then the debug information should come from the state_before of the If.
728 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
729 return;
730 }
731
732 if (lt->is_constant() && rt->is_constant()) {
733 if (x->x()->as_Constant() != NULL) {
734 // pattern: If (lc cond rc) => simplify to: Goto
735 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
736 x->sux_for(true),
737 x->sux_for(false));
738 if (sux != NULL) {
739 // If is a safepoint then the debug information should come from the state_before of the If.
740 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
741 }
742 }
743 } else if (rt->as_IntConstant() != NULL) {
744 // pattern: If (l cond rc) => investigate further
745 const jint rc = rt->as_IntConstant()->value();
746 if (l->as_CompareOp() != NULL) {
747 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
748 CompareOp* cmp = l->as_CompareOp();
749 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
750 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
751 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
752 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
753 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
754 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
755 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
756 // lss_sux or gtr_sux.
757 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
758 // all successors identical => simplify to: Goto
759 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
760 } else {
761 // two successors differ and two successors are the same => simplify to: If (x cmp y)
762 // determine new condition & successors
763 If::Condition cond = If::eql;
764 BlockBegin* tsux = NULL;
765 BlockBegin* fsux = NULL;
766 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
767 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
768 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
769 else { ShouldNotReachHere(); }
770 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
771 if (cmp->x() == cmp->y()) {
772 do_If(canon);
773 } else {
774 if (compilation()->profile_branches()) {
775 // TODO: If profiling, leave floating point comparisons unoptimized.
776 // We currently do not support profiling of the unordered case.
777 switch(cmp->op()) {
778 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
779 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
780 set_canonical(x);
781 return;
782 default:
783 break;
784 }
785 }
786 set_bci(cmp->state_before()->bci());
787 set_canonical(canon);
788 }
789 }
790 } else if (l->as_InstanceOf() != NULL) {
791 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
792 // instruction in the graph (it is pinned). Need to fix this at some point.
793 // It should also be left in the graph when generating a profiled method version or Goto
794 // has to know that it was an InstanceOf.
795 return;
796 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
797 InstanceOf* inst = l->as_InstanceOf();
798 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
799 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
800 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
801 // both successors identical and klass is loaded => simplify to: Goto
802 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
803 } else {
804 // successors differ => simplify to: IfInstanceOf
805 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
806 }
807 }
808 } else if (rt == objectNull &&
809 (l->as_NewInstance() || l->as_NewArray() ||
810 (l->as_Local() && l->as_Local()->is_receiver()))) {
811 if (x->cond() == Instruction::eql) {
812 BlockBegin* sux = x->fsux();
813 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
814 } else {
815 assert(x->cond() == Instruction::neq, "only other valid case");
816 BlockBegin* sux = x->tsux();
817 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
818 }
819 }
820 }
821
822
823 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
824 if (x->tag()->type()->is_constant()) {
825 int v = x->tag()->type()->as_IntConstant()->value();
826 BlockBegin* sux = x->default_sux();
827 if (v >= x->lo_key() && v <= x->hi_key()) {
828 sux = x->sux_at(v - x->lo_key());
829 }
830 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
831 } else if (x->number_of_sux() == 1) {
832 // NOTE: Code permanently disabled for now since the switch statement's
833 // tag expression may produce side-effects in which case it must
834 // be executed.
835 return;
836 // simplify to Goto
837 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
838 } else if (x->number_of_sux() == 2) {
839 // NOTE: Code permanently disabled for now since it produces two new nodes
840 // (Constant & If) and the Canonicalizer cannot return them correctly
841 // yet. For now we copied the corresponding code directly into the
842 // GraphBuilder (i.e., we should never reach here).
843 return;
844 // simplify to If
845 assert(x->lo_key() == x->hi_key(), "keys must be the same");
846 Constant* key = new Constant(new IntConstant(x->lo_key()));
847 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
848 }
849 }
850
851
852 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
853 if (x->tag()->type()->is_constant()) {
854 int v = x->tag()->type()->as_IntConstant()->value();
855 BlockBegin* sux = x->default_sux();
856 for (int i = 0; i < x->length(); i++) {
857 if (v == x->key_at(i)) {
858 sux = x->sux_at(i);
859 }
860 }
861 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
862 } else if (x->number_of_sux() == 1) {
863 // NOTE: Code permanently disabled for now since the switch statement's
864 // tag expression may produce side-effects in which case it must
865 // be executed.
866 return;
867 // simplify to Goto
868 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
869 } else if (x->number_of_sux() == 2) {
870 // NOTE: Code permanently disabled for now since it produces two new nodes
871 // (Constant & If) and the Canonicalizer cannot return them correctly
872 // yet. For now we copied the corresponding code directly into the
873 // GraphBuilder (i.e., we should never reach here).
874 return;
875 // simplify to If
876 assert(x->length() == 1, "length must be the same");
877 Constant* key = new Constant(new IntConstant(x->key_at(0)));
878 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
879 }
880 }
881
882
883 void Canonicalizer::do_Return (Return* x) {}
884 void Canonicalizer::do_Throw (Throw* x) {}
885 void Canonicalizer::do_Base (Base* x) {}
886 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
887 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
888
889 static bool match_index_and_scale(Instruction* instr,
890 Instruction** index,
891 int* log2_scale) {
892 // Skip conversion ops. This works only on 32bit because of the implicit l2i that the
893 // unsafe performs.
894 #ifndef _LP64
895 Convert* convert = instr->as_Convert();
896 if (convert != NULL && convert->op() == Bytecodes::_i2l) {
897 assert(convert->value()->type() == intType, "invalid input type");
898 instr = convert->value();
899 }
900 #endif
901
902 ShiftOp* shift = instr->as_ShiftOp();
903 if (shift != NULL) {
904 if (shift->op() == Bytecodes::_lshl) {
905 assert(shift->x()->type() == longType, "invalid input type");
906 } else {
907 #ifndef _LP64
908 if (shift->op() == Bytecodes::_ishl) {
909 assert(shift->x()->type() == intType, "invalid input type");
910 } else {
911 return false;
912 }
913 #else
914 return false;
915 #endif
916 }
917
918
919 // Constant shift value?
920 Constant* con = shift->y()->as_Constant();
921 if (con == NULL) return false;
922 // Well-known type and value?
923 IntConstant* val = con->type()->as_IntConstant();
924 assert(val != NULL, "Should be an int constant");
925
926 *index = shift->x();
927 int tmp_scale = val->value();
928 if (tmp_scale >= 0 && tmp_scale < 4) {
929 *log2_scale = tmp_scale;
930 return true;
931 } else {
932 return false;
933 }
934 }
935
936 ArithmeticOp* arith = instr->as_ArithmeticOp();
937 if (arith != NULL) {
938 // See if either arg is a known constant
939 Constant* con = arith->x()->as_Constant();
940 if (con != NULL) {
941 *index = arith->y();
942 } else {
943 con = arith->y()->as_Constant();
944 if (con == NULL) return false;
945 *index = arith->x();
946 }
947 long const_value;
948 // Check for integer multiply
949 if (arith->op() == Bytecodes::_lmul) {
950 assert((*index)->type() == longType, "invalid input type");
951 LongConstant* val = con->type()->as_LongConstant();
952 assert(val != NULL, "expecting a long constant");
953 const_value = val->value();
954 } else {
955 #ifndef _LP64
956 if (arith->op() == Bytecodes::_imul) {
957 assert((*index)->type() == intType, "invalid input type");
958 IntConstant* val = con->type()->as_IntConstant();
959 assert(val != NULL, "expecting an int constant");
960 const_value = val->value();
961 } else {
962 return false;
963 }
964 #else
965 return false;
966 #endif
967 }
968 switch (const_value) {
969 case 1: *log2_scale = 0; return true;
970 case 2: *log2_scale = 1; return true;
971 case 4: *log2_scale = 2; return true;
972 case 8: *log2_scale = 3; return true;
973 default: return false;
974 }
975 }
976
977 // Unknown instruction sequence; don't touch it
978 return false;
979 }
980
981
982 static bool match(UnsafeRawOp* x,
983 Instruction** base,
984 Instruction** index,
985 int* log2_scale) {
986 ArithmeticOp* root = x->base()->as_ArithmeticOp();
987 if (root == NULL) return false;
988 // Limit ourselves to addition for now
989 if (root->op() != Bytecodes::_ladd) return false;
990
991 bool match_found = false;
992 // Try to find shift or scale op
993 if (match_index_and_scale(root->y(), index, log2_scale)) {
994 *base = root->x();
995 match_found = true;
996 } else if (match_index_and_scale(root->x(), index, log2_scale)) {
997 *base = root->y();
998 match_found = true;
999 } else if (NOT_LP64(root->y()->as_Convert() != NULL) LP64_ONLY(false)) {
1000 // Skipping i2l works only on 32bit because of the implicit l2i that the unsafe performs.
1001 // 64bit needs a real sign-extending conversion.
1002 Convert* convert = root->y()->as_Convert();
1003 if (convert->op() == Bytecodes::_i2l) {
1004 assert(convert->value()->type() == intType, "should be an int");
1005 // pick base and index, setting scale at 1
1006 *base = root->x();
1007 *index = convert->value();
1008 *log2_scale = 0;
1009 match_found = true;
1010 }
1011 }
1012 // The default solution
1013 if (!match_found) {
1014 *base = root->x();
1015 *index = root->y();
1016 *log2_scale = 0;
1017 }
1018
1019 // If the value is pinned then it will be always be computed so
1020 // there's no profit to reshaping the expression.
1021 return !root->is_pinned();
1022 }
1023
1024
1025 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
1026 Instruction* base = NULL;
1027 Instruction* index = NULL;
1028 int log2_scale;
1029
1030 if (match(x, &base, &index, &log2_scale)) {
1031 x->set_base(base);
1032 x->set_index(index);
1033 x->set_log2_scale(log2_scale);
1034 if (PrintUnsafeOptimization) {
1035 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
1036 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
1037 }
1038 }
1039 }
1040
1041 void Canonicalizer::do_RoundFP(RoundFP* x) {}
1042 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
1043 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
1044 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
1045 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
1046 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
1047 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
1048 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
1049 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
1050 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}
1051 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
1052 #ifdef ASSERT
1053 void Canonicalizer::do_Assert(Assert* x) {}
1054 #endif
1055 void Canonicalizer::do_MemBar(MemBar* x) {}