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