1 /*
2 * Copyright (c) 1999, 2015, 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 }
82 }
83
84 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
85 // do constant folding for selected operations
86 switch (x->type()->tag()) {
87 case intTag:
88 { jint a = x->x()->type()->as_IntConstant()->value();
89 jint b = x->y()->type()->as_IntConstant()->value();
90 switch (x->op()) {
91 case Bytecodes::_iadd: set_constant(a + b); return;
92 case Bytecodes::_isub: set_constant(a - b); return;
93 case Bytecodes::_imul: set_constant(a * b); return;
94 case Bytecodes::_idiv:
95 if (b != 0) {
96 if (a == min_jint && b == -1) {
97 set_constant(min_jint);
98 } else {
99 set_constant(a / b);
100 }
101 return;
102 }
103 break;
104 case Bytecodes::_irem:
105 if (b != 0) {
106 if (a == min_jint && b == -1) {
107 set_constant(0);
108 } else {
109 set_constant(a % b);
110 }
111 return;
112 }
113 break;
114 case Bytecodes::_iand: set_constant(a & b); return;
115 case Bytecodes::_ior : set_constant(a | b); return;
116 case Bytecodes::_ixor: set_constant(a ^ b); return;
117 }
118 }
119 break;
120 case longTag:
121 { jlong a = x->x()->type()->as_LongConstant()->value();
122 jlong b = x->y()->type()->as_LongConstant()->value();
123 switch (x->op()) {
124 case Bytecodes::_ladd: set_constant(a + b); return;
125 case Bytecodes::_lsub: set_constant(a - b); return;
126 case Bytecodes::_lmul: set_constant(a * b); return;
127 case Bytecodes::_ldiv:
128 if (b != 0) {
129 set_constant(SharedRuntime::ldiv(b, a));
130 return;
131 }
132 break;
133 case Bytecodes::_lrem:
134 if (b != 0) {
135 set_constant(SharedRuntime::lrem(b, a));
136 return;
137 }
138 break;
139 case Bytecodes::_land: set_constant(a & b); return;
140 case Bytecodes::_lor : set_constant(a | b); return;
141 case Bytecodes::_lxor: set_constant(a ^ b); return;
142 }
143 }
144 break;
145 // other cases not implemented (must be extremely careful with floats & doubles!)
146 }
147 }
148 // make sure constant is on the right side, if any
149 move_const_to_right(x);
150
151 if (x->y()->type()->is_constant()) {
152 // do constant folding for selected operations
153 switch (x->type()->tag()) {
154 case intTag:
155 if (x->y()->type()->as_IntConstant()->value() == 0) {
156 switch (x->op()) {
157 case Bytecodes::_iadd: set_canonical(x->x()); return;
158 case Bytecodes::_isub: set_canonical(x->x()); return;
159 case Bytecodes::_imul: set_constant(0); return;
160 // Note: for div and rem, make sure that C semantics
161 // corresponds to Java semantics!
162 case Bytecodes::_iand: set_constant(0); return;
163 case Bytecodes::_ior : set_canonical(x->x()); return;
164 }
165 }
166 break;
167 case longTag:
168 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
169 switch (x->op()) {
170 case Bytecodes::_ladd: set_canonical(x->x()); return;
171 case Bytecodes::_lsub: set_canonical(x->x()); return;
172 case Bytecodes::_lmul: set_constant((jlong)0); return;
173 // Note: for div and rem, make sure that C semantics
174 // corresponds to Java semantics!
175 case Bytecodes::_land: set_constant((jlong)0); return;
176 case Bytecodes::_lor : set_canonical(x->x()); return;
177 }
178 }
179 break;
180 }
181 }
182 }
183
184
185 void Canonicalizer::do_Phi (Phi* x) {}
186 void Canonicalizer::do_Constant (Constant* x) {}
187 void Canonicalizer::do_Local (Local* x) {}
188 void Canonicalizer::do_LoadField (LoadField* x) {}
189
190 // checks if v is in the block that is currently processed by
191 // GraphBuilder. This is the only block that has not BlockEnd yet.
192 static bool in_current_block(Value v) {
193 int max_distance = 4;
194 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
195 v = v->next();
196 max_distance--;
197 }
198 return v == NULL;
199 }
200
201 void Canonicalizer::do_StoreField (StoreField* x) {
202 // If a value is going to be stored into a field or array some of
203 // the conversions emitted by javac are unneeded because the fields
204 // are packed to their natural size.
205 Convert* conv = x->value()->as_Convert();
206 if (conv) {
207 Value value = NULL;
208 BasicType type = x->field()->type()->basic_type();
209 switch (conv->op()) {
210 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
211 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
212 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
213 }
214 // limit this optimization to current block
215 if (value != NULL && in_current_block(conv)) {
216 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
217 x->state_before(), x->needs_patching()));
218 return;
219 }
220 }
221
222 }
223
224 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
225 NewArray* na;
226 Constant* ct;
227 LoadField* lf;
228
229 if ((na = x->array()->as_NewArray()) != NULL) {
230 // New arrays might have the known length.
231 // Do not use the Constant itself, but create a new Constant
232 // with same value Otherwise a Constant is live over multiple
233 // blocks without being registered in a state array.
234 Constant* length;
235 if (na->length() != NULL &&
236 (length = na->length()->as_Constant()) != NULL) {
237 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
238 set_constant(length->type()->as_IntConstant()->value());
239 }
240
241 } else if ((ct = x->array()->as_Constant()) != NULL) {
242 // Constant arrays have constant lengths.
243 ArrayConstant* cnst = ct->type()->as_ArrayConstant();
244 if (cnst != NULL) {
245 set_constant(cnst->value()->length());
246 }
247
248 } else if ((lf = x->array()->as_LoadField()) != NULL) {
249 ciField* field = lf->field();
250 if (field->is_constant() && field->is_static()) {
251 assert(PatchALot || ScavengeRootsInCode < 2, "Constant field loads are folded during parsing");
252 ciObject* c = field->constant_value().as_object();
253 if (!c->is_null_object()) {
254 set_constant(c->as_array()->length());
255 }
256 }
257 }
258 }
259
260 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {}
261 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
262 // If a value is going to be stored into a field or array some of
263 // the conversions emitted by javac are unneeded because the fields
264 // are packed to their natural size.
265 Convert* conv = x->value()->as_Convert();
266 if (conv) {
267 Value value = NULL;
268 BasicType type = x->elt_type();
269 switch (conv->op()) {
270 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
271 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
272 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
273 }
274 // limit this optimization to current block
275 if (value != NULL && in_current_block(conv)) {
276 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
277 x->elt_type(), value, x->state_before()));
278 return;
279 }
280 }
281
282
283 }
284
285
286 void Canonicalizer::do_NegateOp(NegateOp* x) {
287 ValueType* t = x->x()->type();
288 if (t->is_constant()) {
289 switch (t->tag()) {
290 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
291 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
292 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
293 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
294 default : ShouldNotReachHere();
295 }
296 }
297 }
298
299
300 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
301
302
303 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
304 ValueType* t = x->x()->type();
305 ValueType* t2 = x->y()->type();
306 if (t->is_constant()) {
307 switch (t->tag()) {
308 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
309 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
310 default : ShouldNotReachHere();
311 }
312 if (t2->is_constant()) {
313 if (t->tag() == intTag) {
314 int value = t->as_IntConstant()->value();
315 int shift = t2->as_IntConstant()->value() & 31;
316 jint mask = ~(~0 << (32 - shift));
317 if (shift == 0) mask = ~0;
318 switch (x->op()) {
319 case Bytecodes::_ishl: set_constant(value << shift); return;
320 case Bytecodes::_ishr: set_constant(value >> shift); return;
321 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
322 }
323 } else if (t->tag() == longTag) {
324 jlong value = t->as_LongConstant()->value();
325 int shift = t2->as_IntConstant()->value() & 63;
326 jlong mask = ~(~jlong_cast(0) << (64 - shift));
327 if (shift == 0) mask = ~jlong_cast(0);
328 switch (x->op()) {
329 case Bytecodes::_lshl: set_constant(value << shift); return;
330 case Bytecodes::_lshr: set_constant(value >> shift); return;
331 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
332 }
333 }
334 }
335 }
336 if (t2->is_constant()) {
337 switch (t2->tag()) {
338 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
339 case longTag : if (t2->as_LongConstant()->value() == (jlong)0) set_canonical(x->x()); return;
340 default : ShouldNotReachHere();
341 }
342 }
343 }
344
345
346 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
347 void Canonicalizer::do_CompareOp (CompareOp* x) {
348 if (x->x() == x->y()) {
349 switch (x->x()->type()->tag()) {
350 case longTag: set_constant(0); break;
351 case floatTag: {
352 FloatConstant* fc = x->x()->type()->as_FloatConstant();
353 if (fc) {
354 if (g_isnan(fc->value())) {
355 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
356 } else {
357 set_constant(0);
358 }
359 }
360 break;
361 }
362 case doubleTag: {
363 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
364 if (dc) {
365 if (g_isnan(dc->value())) {
366 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
367 } else {
368 set_constant(0);
369 }
370 }
371 break;
372 }
373 }
374 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
375 switch (x->x()->type()->tag()) {
376 case longTag: {
377 jlong vx = x->x()->type()->as_LongConstant()->value();
378 jlong vy = x->y()->type()->as_LongConstant()->value();
379 if (vx == vy)
380 set_constant(0);
381 else if (vx < vy)
382 set_constant(-1);
383 else
384 set_constant(1);
385 break;
386 }
387
388 case floatTag: {
389 float vx = x->x()->type()->as_FloatConstant()->value();
390 float vy = x->y()->type()->as_FloatConstant()->value();
391 if (g_isnan(vx) || g_isnan(vy))
392 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
393 else if (vx == vy)
394 set_constant(0);
395 else if (vx < vy)
396 set_constant(-1);
397 else
398 set_constant(1);
399 break;
400 }
401
402 case doubleTag: {
403 double vx = x->x()->type()->as_DoubleConstant()->value();
404 double vy = x->y()->type()->as_DoubleConstant()->value();
405 if (g_isnan(vx) || g_isnan(vy))
406 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
407 else if (vx == vy)
408 set_constant(0);
409 else if (vx < vy)
410 set_constant(-1);
411 else
412 set_constant(1);
413 break;
414 }
415 }
416
417 }
418 }
419
420
421 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
422
423 void Canonicalizer::do_IfOp(IfOp* x) {
424 // Caution: do not use do_Op2(x) here for now since
425 // we map the condition to the op for now!
426 move_const_to_right(x);
427 }
428
429
430 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
431 switch (x->id()) {
432 case vmIntrinsics::_floatToRawIntBits : {
433 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
434 if (c != NULL) {
435 JavaValue v;
436 v.set_jfloat(c->value());
437 set_constant(v.get_jint());
438 }
439 break;
440 }
441 case vmIntrinsics::_intBitsToFloat : {
442 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
443 if (c != NULL) {
444 JavaValue v;
445 v.set_jint(c->value());
446 set_constant(v.get_jfloat());
447 }
448 break;
449 }
450 case vmIntrinsics::_doubleToRawLongBits : {
451 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
452 if (c != NULL) {
453 JavaValue v;
454 v.set_jdouble(c->value());
455 set_constant(v.get_jlong());
456 }
457 break;
458 }
459 case vmIntrinsics::_longBitsToDouble : {
460 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
461 if (c != NULL) {
462 JavaValue v;
463 v.set_jlong(c->value());
464 set_constant(v.get_jdouble());
465 }
466 break;
467 }
468 case vmIntrinsics::_isInstance : {
469 assert(x->number_of_arguments() == 2, "wrong type");
470
471 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
472 if (c != NULL && !c->value()->is_null_object()) {
473 // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors
474 ciType* t = c->value()->as_instance()->java_mirror_type();
475 if (t->is_klass()) {
476 // substitute cls.isInstance(obj) of a constant Class into
477 // an InstantOf instruction
478 InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before());
479 set_canonical(i);
480 // and try to canonicalize even further
481 do_InstanceOf(i);
482 } else {
483 assert(t->is_primitive_type(), "should be a primitive type");
484 // cls.isInstance(obj) always returns false for primitive classes
485 set_constant(0);
486 }
487 }
488 break;
489 }
490 }
491 }
492
493 void Canonicalizer::do_Convert (Convert* x) {
494 if (x->value()->type()->is_constant()) {
495 switch (x->op()) {
496 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
497 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
498 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
499 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
500 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
501 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
502 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
503 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
504 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
505 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
506 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
507 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
508 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
509 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
510 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
511 default:
512 ShouldNotReachHere();
513 }
514 }
515
516 Value value = x->value();
517 BasicType type = T_ILLEGAL;
518 LoadField* lf = value->as_LoadField();
519 if (lf) {
520 type = lf->field_type();
521 } else {
522 LoadIndexed* li = value->as_LoadIndexed();
523 if (li) {
524 type = li->elt_type();
525 } else {
526 Convert* conv = value->as_Convert();
527 if (conv) {
528 switch (conv->op()) {
529 case Bytecodes::_i2b: type = T_BYTE; break;
530 case Bytecodes::_i2s: type = T_SHORT; break;
531 case Bytecodes::_i2c: type = T_CHAR; break;
532 }
533 }
534 }
535 }
536 if (type != T_ILLEGAL) {
537 switch (x->op()) {
538 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
539 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
540 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
541 }
542 } else {
543 Op2* op2 = x->value()->as_Op2();
544 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
545 jint safebits = 0;
546 jint mask = op2->y()->type()->as_IntConstant()->value();
547 switch (x->op()) {
548 case Bytecodes::_i2b: safebits = 0x7f; break;
549 case Bytecodes::_i2s: safebits = 0x7fff; break;
550 case Bytecodes::_i2c: safebits = 0xffff; break;
551 }
552 // When casting a masked integer to a smaller signed type, if
553 // the mask doesn't include the sign bit the cast isn't needed.
554 if (safebits && (mask & ~safebits) == 0) {
555 set_canonical(x->value());
556 }
557 }
558 }
559
560 }
561
562 void Canonicalizer::do_NullCheck (NullCheck* x) {
563 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
564 set_canonical(x->obj());
565 } else {
566 Constant* con = x->obj()->as_Constant();
567 if (con) {
568 ObjectType* c = con->type()->as_ObjectType();
569 if (c && c->is_loaded()) {
570 ObjectConstant* oc = c->as_ObjectConstant();
571 if (!oc || !oc->value()->is_null_object()) {
572 set_canonical(con);
573 }
574 }
575 }
576 }
577 }
578
579 void Canonicalizer::do_TypeCast (TypeCast* x) {}
580 void Canonicalizer::do_Invoke (Invoke* x) {}
581 void Canonicalizer::do_NewInstance (NewInstance* x) {}
582 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
583 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
584 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
585 void Canonicalizer::do_CheckCast (CheckCast* x) {
586 if (x->klass()->is_loaded()) {
587 Value obj = x->obj();
588 ciType* klass = obj->exact_type();
589 if (klass == NULL) klass = obj->declared_type();
590 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
591 set_canonical(obj);
592 return;
593 }
594 // checkcast of null returns null
595 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
596 set_canonical(obj);
597 }
598 }
599 }
600 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
601 if (x->klass()->is_loaded()) {
602 Value obj = x->obj();
603 ciType* exact = obj->exact_type();
604 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
605 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
606 return;
607 }
608 // instanceof null returns false
609 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
610 set_constant(0);
611 }
612 }
613
614 }
615 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
616 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
617 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
618 void Canonicalizer::do_Goto (Goto* x) {}
619
620
621 static bool is_true(jlong x, If::Condition cond, jlong y) {
622 switch (cond) {
623 case If::eql: return x == y;
624 case If::neq: return x != y;
625 case If::lss: return x < y;
626 case If::leq: return x <= y;
627 case If::gtr: return x > y;
628 case If::geq: return x >= y;
629 }
630 ShouldNotReachHere();
631 return false;
632 }
633
634 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
635 // An Instruction with multiple successors, x, is replaced by a Goto
636 // to a single successor, sux. Is a safepoint check needed = was the
637 // instruction being replaced a safepoint and the single remaining
638 // successor a back branch?
639 return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
640 }
641
642 void Canonicalizer::do_If(If* x) {
643 // move const to right
644 if (x->x()->type()->is_constant()) x->swap_operands();
645 // simplify
646 const Value l = x->x(); ValueType* lt = l->type();
647 const Value r = x->y(); ValueType* rt = r->type();
648
649 if (l == r && !lt->is_float_kind()) {
650 // pattern: If (a cond a) => simplify to Goto
651 BlockBegin* sux = NULL;
652 switch (x->cond()) {
653 case If::eql: sux = x->sux_for(true); break;
654 case If::neq: sux = x->sux_for(false); break;
655 case If::lss: sux = x->sux_for(false); break;
656 case If::leq: sux = x->sux_for(true); break;
657 case If::gtr: sux = x->sux_for(false); break;
658 case If::geq: sux = x->sux_for(true); break;
659 default: ShouldNotReachHere();
660 }
661 // If is a safepoint then the debug information should come from the state_before of the If.
662 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
663 return;
664 }
665
666 if (lt->is_constant() && rt->is_constant()) {
667 if (x->x()->as_Constant() != NULL) {
668 // pattern: If (lc cond rc) => simplify to: Goto
669 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
670 x->sux_for(true),
671 x->sux_for(false));
672 if (sux != NULL) {
673 // If is a safepoint then the debug information should come from the state_before of the If.
674 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
675 }
676 }
677 } else if (rt->as_IntConstant() != NULL) {
678 // pattern: If (l cond rc) => investigate further
679 const jint rc = rt->as_IntConstant()->value();
680 if (l->as_CompareOp() != NULL) {
681 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
682 CompareOp* cmp = l->as_CompareOp();
683 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
684 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
685 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
686 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
687 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
688 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
689 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
690 // lss_sux or gtr_sux.
691 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
692 // all successors identical => simplify to: Goto
693 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
694 } else {
695 // two successors differ and two successors are the same => simplify to: If (x cmp y)
696 // determine new condition & successors
697 If::Condition cond = If::eql;
698 BlockBegin* tsux = NULL;
699 BlockBegin* fsux = NULL;
700 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
701 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
702 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
703 else { ShouldNotReachHere(); }
704 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
705 if (cmp->x() == cmp->y()) {
706 do_If(canon);
707 } else {
708 if (compilation()->profile_branches()) {
709 // TODO: If profiling, leave floating point comparisons unoptimized.
710 // We currently do not support profiling of the unordered case.
711 switch(cmp->op()) {
712 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
713 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
714 set_canonical(x);
715 return;
716 }
717 }
718 set_bci(cmp->state_before()->bci());
719 set_canonical(canon);
720 }
721 }
722 } else if (l->as_InstanceOf() != NULL) {
723 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
724 // instruction in the graph (it is pinned). Need to fix this at some point.
725 // It should also be left in the graph when generating a profiled method version or Goto
726 // has to know that it was an InstanceOf.
727 return;
728 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
729 InstanceOf* inst = l->as_InstanceOf();
730 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
731 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
732 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
733 // both successors identical and klass is loaded => simplify to: Goto
734 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
735 } else {
736 // successors differ => simplify to: IfInstanceOf
737 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
738 }
739 }
740 } else if (rt == objectNull &&
741 (l->as_NewInstance() || l->as_NewArray() ||
742 (l->as_Local() && l->as_Local()->is_receiver()))) {
743 if (x->cond() == Instruction::eql) {
744 BlockBegin* sux = x->fsux();
745 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
746 } else {
747 assert(x->cond() == Instruction::neq, "only other valid case");
748 BlockBegin* sux = x->tsux();
749 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
750 }
751 }
752 }
753
754
755 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
756 if (x->tag()->type()->is_constant()) {
757 int v = x->tag()->type()->as_IntConstant()->value();
758 BlockBegin* sux = x->default_sux();
759 if (v >= x->lo_key() && v <= x->hi_key()) {
760 sux = x->sux_at(v - x->lo_key());
761 }
762 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
763 } else if (x->number_of_sux() == 1) {
764 // NOTE: Code permanently disabled for now since the switch statement's
765 // tag expression may produce side-effects in which case it must
766 // be executed.
767 return;
768 // simplify to Goto
769 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
770 } else if (x->number_of_sux() == 2) {
771 // NOTE: Code permanently disabled for now since it produces two new nodes
772 // (Constant & If) and the Canonicalizer cannot return them correctly
773 // yet. For now we copied the corresponding code directly into the
774 // GraphBuilder (i.e., we should never reach here).
775 return;
776 // simplify to If
777 assert(x->lo_key() == x->hi_key(), "keys must be the same");
778 Constant* key = new Constant(new IntConstant(x->lo_key()));
779 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
780 }
781 }
782
783
784 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
785 if (x->tag()->type()->is_constant()) {
786 int v = x->tag()->type()->as_IntConstant()->value();
787 BlockBegin* sux = x->default_sux();
788 for (int i = 0; i < x->length(); i++) {
789 if (v == x->key_at(i)) {
790 sux = x->sux_at(i);
791 }
792 }
793 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
794 } else if (x->number_of_sux() == 1) {
795 // NOTE: Code permanently disabled for now since the switch statement's
796 // tag expression may produce side-effects in which case it must
797 // be executed.
798 return;
799 // simplify to Goto
800 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
801 } else if (x->number_of_sux() == 2) {
802 // NOTE: Code permanently disabled for now since it produces two new nodes
803 // (Constant & If) and the Canonicalizer cannot return them correctly
804 // yet. For now we copied the corresponding code directly into the
805 // GraphBuilder (i.e., we should never reach here).
806 return;
807 // simplify to If
808 assert(x->length() == 1, "length must be the same");
809 Constant* key = new Constant(new IntConstant(x->key_at(0)));
810 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
811 }
812 }
813
814
815 void Canonicalizer::do_Return (Return* x) {}
816 void Canonicalizer::do_Throw (Throw* x) {}
817 void Canonicalizer::do_Base (Base* x) {}
818 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
819 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
820
821 static bool match_index_and_scale(Instruction* instr,
822 Instruction** index,
823 int* log2_scale) {
824 // Skip conversion ops. This works only on 32bit because of the implicit l2i that the
825 // unsafe performs.
826 #ifndef _LP64
827 Convert* convert = instr->as_Convert();
828 if (convert != NULL && convert->op() == Bytecodes::_i2l) {
829 assert(convert->value()->type() == intType, "invalid input type");
830 instr = convert->value();
831 }
832 #endif
833
834 ShiftOp* shift = instr->as_ShiftOp();
835 if (shift != NULL) {
836 if (shift->op() == Bytecodes::_lshl) {
837 assert(shift->x()->type() == longType, "invalid input type");
838 } else {
839 #ifndef _LP64
840 if (shift->op() == Bytecodes::_ishl) {
841 assert(shift->x()->type() == intType, "invalid input type");
842 } else {
843 return false;
844 }
845 #else
846 return false;
847 #endif
848 }
849
850
851 // Constant shift value?
852 Constant* con = shift->y()->as_Constant();
853 if (con == NULL) return false;
854 // Well-known type and value?
855 IntConstant* val = con->type()->as_IntConstant();
856 assert(val != NULL, "Should be an int constant");
857
858 *index = shift->x();
859 int tmp_scale = val->value();
860 if (tmp_scale >= 0 && tmp_scale < 4) {
861 *log2_scale = tmp_scale;
862 return true;
863 } else {
864 return false;
865 }
866 }
867
868 ArithmeticOp* arith = instr->as_ArithmeticOp();
869 if (arith != NULL) {
870 // See if either arg is a known constant
871 Constant* con = arith->x()->as_Constant();
872 if (con != NULL) {
873 *index = arith->y();
874 } else {
875 con = arith->y()->as_Constant();
876 if (con == NULL) return false;
877 *index = arith->x();
878 }
879 long const_value;
880 // Check for integer multiply
881 if (arith->op() == Bytecodes::_lmul) {
882 assert((*index)->type() == longType, "invalid input type");
883 LongConstant* val = con->type()->as_LongConstant();
884 assert(val != NULL, "expecting a long constant");
885 const_value = val->value();
886 } else {
887 #ifndef _LP64
888 if (arith->op() == Bytecodes::_imul) {
889 assert((*index)->type() == intType, "invalid input type");
890 IntConstant* val = con->type()->as_IntConstant();
891 assert(val != NULL, "expecting an int constant");
892 const_value = val->value();
893 } else {
894 return false;
895 }
896 #else
897 return false;
898 #endif
899 }
900 switch (const_value) {
901 case 1: *log2_scale = 0; return true;
902 case 2: *log2_scale = 1; return true;
903 case 4: *log2_scale = 2; return true;
904 case 8: *log2_scale = 3; return true;
905 default: return false;
906 }
907 }
908
909 // Unknown instruction sequence; don't touch it
910 return false;
911 }
912
913
914 static bool match(UnsafeRawOp* x,
915 Instruction** base,
916 Instruction** index,
917 int* log2_scale) {
918 ArithmeticOp* root = x->base()->as_ArithmeticOp();
919 if (root == NULL) return false;
920 // Limit ourselves to addition for now
921 if (root->op() != Bytecodes::_ladd) return false;
922
923 bool match_found = false;
924 // Try to find shift or scale op
925 if (match_index_and_scale(root->y(), index, log2_scale)) {
926 *base = root->x();
927 match_found = true;
928 } else if (match_index_and_scale(root->x(), index, log2_scale)) {
929 *base = root->y();
930 match_found = true;
931 } else if (NOT_LP64(root->y()->as_Convert() != NULL) LP64_ONLY(false)) {
932 // Skipping i2l works only on 32bit because of the implicit l2i that the unsafe performs.
933 // 64bit needs a real sign-extending conversion.
934 Convert* convert = root->y()->as_Convert();
935 if (convert->op() == Bytecodes::_i2l) {
936 assert(convert->value()->type() == intType, "should be an int");
937 // pick base and index, setting scale at 1
938 *base = root->x();
939 *index = convert->value();
940 *log2_scale = 0;
941 match_found = true;
942 }
943 }
944 // The default solution
945 if (!match_found) {
946 *base = root->x();
947 *index = root->y();
948 *log2_scale = 0;
949 }
950
951 // If the value is pinned then it will be always be computed so
952 // there's no profit to reshaping the expression.
953 return !root->is_pinned();
954 }
955
956
957 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
958 Instruction* base = NULL;
959 Instruction* index = NULL;
960 int log2_scale;
961
962 if (match(x, &base, &index, &log2_scale)) {
963 x->set_base(base);
964 x->set_index(index);
965 x->set_log2_scale(log2_scale);
966 if (PrintUnsafeOptimization) {
967 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
968 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
969 }
970 }
971 }
972
973 void Canonicalizer::do_RoundFP(RoundFP* x) {}
974 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
975 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
976 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
977 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
978 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
979 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
980 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
981 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
982 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}
983 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
984 #ifdef ASSERT
985 void Canonicalizer::do_Assert(Assert* x) {}
986 #endif
987 void Canonicalizer::do_MemBar(MemBar* x) {}