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 StableArrayConstant* array = x->array()->type()->as_StableArrayConstant();
262 IntConstant* index = x->index()->type()->as_IntConstant();
263
264 assert(array == NULL || FoldStableValues, "not enabled");
265
266 // Constant fold loads from stable arrays.
267 if (array != NULL && index != NULL) {
268 jint idx = index->value();
269 if (idx < 0 || idx >= array->value()->length()) {
270 // Leave the load as is. The range check will handle it.
271 return;
272 }
273
274 ciConstant field_val = array->value()->element_value(idx);
275 if (!field_val.is_null_or_zero()) {
276 jint dimension = array->dimension();
277 assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info");
278 ValueType* value = NULL;
279 if (dimension > 1) {
280 // Preserve information about the dimension for the element.
281 assert(field_val.as_object()->is_array(), "not an array");
282 value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1);
283 } else {
284 assert(dimension == 1, "sanity");
285 value = as_ValueType(field_val);
286 }
287 set_canonical(new Constant(value));
288 }
289 }
290 }
291
292 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
293 // If a value is going to be stored into a field or array some of
294 // the conversions emitted by javac are unneeded because the fields
295 // are packed to their natural size.
296 Convert* conv = x->value()->as_Convert();
297 if (conv) {
298 Value value = NULL;
299 BasicType type = x->elt_type();
300 switch (conv->op()) {
301 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
302 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
303 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
304 }
305 // limit this optimization to current block
306 if (value != NULL && in_current_block(conv)) {
307 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
308 x->elt_type(), value, x->state_before()));
309 return;
310 }
311 }
312
313
314 }
315
316
317 void Canonicalizer::do_NegateOp(NegateOp* x) {
318 ValueType* t = x->x()->type();
319 if (t->is_constant()) {
320 switch (t->tag()) {
321 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
322 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
323 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
324 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
325 default : ShouldNotReachHere();
326 }
327 }
328 }
329
330
331 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
332
333
334 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
335 ValueType* t = x->x()->type();
336 ValueType* t2 = x->y()->type();
337 if (t->is_constant()) {
338 switch (t->tag()) {
339 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
340 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
341 default : ShouldNotReachHere();
342 }
343 if (t2->is_constant()) {
344 if (t->tag() == intTag) {
345 int value = t->as_IntConstant()->value();
346 int shift = t2->as_IntConstant()->value() & 31;
347 jint mask = ~(~0 << (32 - shift));
348 if (shift == 0) mask = ~0;
349 switch (x->op()) {
350 case Bytecodes::_ishl: set_constant(value << shift); return;
351 case Bytecodes::_ishr: set_constant(value >> shift); return;
352 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
353 }
354 } else if (t->tag() == longTag) {
355 jlong value = t->as_LongConstant()->value();
356 int shift = t2->as_IntConstant()->value() & 63;
357 jlong mask = ~(~jlong_cast(0) << (64 - shift));
358 if (shift == 0) mask = ~jlong_cast(0);
359 switch (x->op()) {
360 case Bytecodes::_lshl: set_constant(value << shift); return;
361 case Bytecodes::_lshr: set_constant(value >> shift); return;
362 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
363 }
364 }
365 }
366 }
367 if (t2->is_constant()) {
368 switch (t2->tag()) {
369 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
370 case longTag : if (t2->as_LongConstant()->value() == (jlong)0) set_canonical(x->x()); return;
371 default : ShouldNotReachHere();
372 }
373 }
374 }
375
376
377 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
378 void Canonicalizer::do_CompareOp (CompareOp* x) {
379 if (x->x() == x->y()) {
380 switch (x->x()->type()->tag()) {
381 case longTag: set_constant(0); break;
382 case floatTag: {
383 FloatConstant* fc = x->x()->type()->as_FloatConstant();
384 if (fc) {
385 if (g_isnan(fc->value())) {
386 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
387 } else {
388 set_constant(0);
389 }
390 }
391 break;
392 }
393 case doubleTag: {
394 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
395 if (dc) {
396 if (g_isnan(dc->value())) {
397 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
398 } else {
399 set_constant(0);
400 }
401 }
402 break;
403 }
404 }
405 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
406 switch (x->x()->type()->tag()) {
407 case longTag: {
408 jlong vx = x->x()->type()->as_LongConstant()->value();
409 jlong vy = x->y()->type()->as_LongConstant()->value();
410 if (vx == vy)
411 set_constant(0);
412 else if (vx < vy)
413 set_constant(-1);
414 else
415 set_constant(1);
416 break;
417 }
418
419 case floatTag: {
420 float vx = x->x()->type()->as_FloatConstant()->value();
421 float vy = x->y()->type()->as_FloatConstant()->value();
422 if (g_isnan(vx) || g_isnan(vy))
423 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
424 else if (vx == vy)
425 set_constant(0);
426 else if (vx < vy)
427 set_constant(-1);
428 else
429 set_constant(1);
430 break;
431 }
432
433 case doubleTag: {
434 double vx = x->x()->type()->as_DoubleConstant()->value();
435 double vy = x->y()->type()->as_DoubleConstant()->value();
436 if (g_isnan(vx) || g_isnan(vy))
437 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
438 else if (vx == vy)
439 set_constant(0);
440 else if (vx < vy)
441 set_constant(-1);
442 else
443 set_constant(1);
444 break;
445 }
446 }
447
448 }
449 }
450
451
452 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
453
454 void Canonicalizer::do_IfOp(IfOp* x) {
455 // Caution: do not use do_Op2(x) here for now since
456 // we map the condition to the op for now!
457 move_const_to_right(x);
458 }
459
460
461 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
462 switch (x->id()) {
463 case vmIntrinsics::_floatToRawIntBits : {
464 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
465 if (c != NULL) {
466 JavaValue v;
467 v.set_jfloat(c->value());
468 set_constant(v.get_jint());
469 }
470 break;
471 }
472 case vmIntrinsics::_intBitsToFloat : {
473 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
474 if (c != NULL) {
475 JavaValue v;
476 v.set_jint(c->value());
477 set_constant(v.get_jfloat());
478 }
479 break;
480 }
481 case vmIntrinsics::_doubleToRawLongBits : {
482 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
483 if (c != NULL) {
484 JavaValue v;
485 v.set_jdouble(c->value());
486 set_constant(v.get_jlong());
487 }
488 break;
489 }
490 case vmIntrinsics::_longBitsToDouble : {
491 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
492 if (c != NULL) {
493 JavaValue v;
494 v.set_jlong(c->value());
495 set_constant(v.get_jdouble());
496 }
497 break;
498 }
499 case vmIntrinsics::_isInstance : {
500 assert(x->number_of_arguments() == 2, "wrong type");
501
502 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
503 if (c != NULL && !c->value()->is_null_object()) {
504 // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors
505 ciType* t = c->value()->as_instance()->java_mirror_type();
506 if (t->is_klass()) {
507 // substitute cls.isInstance(obj) of a constant Class into
508 // an InstantOf instruction
509 InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before());
510 set_canonical(i);
511 // and try to canonicalize even further
512 do_InstanceOf(i);
513 } else {
514 assert(t->is_primitive_type(), "should be a primitive type");
515 // cls.isInstance(obj) always returns false for primitive classes
516 set_constant(0);
517 }
518 }
519 break;
520 }
521 }
522 }
523
524 void Canonicalizer::do_Convert (Convert* x) {
525 if (x->value()->type()->is_constant()) {
526 switch (x->op()) {
527 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
528 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
529 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
530 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
531 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
532 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
533 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
534 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
535 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
536 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
537 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
538 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
539 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
540 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
541 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
542 default:
543 ShouldNotReachHere();
544 }
545 }
546
547 Value value = x->value();
548 BasicType type = T_ILLEGAL;
549 LoadField* lf = value->as_LoadField();
550 if (lf) {
551 type = lf->field_type();
552 } else {
553 LoadIndexed* li = value->as_LoadIndexed();
554 if (li) {
555 type = li->elt_type();
556 } else {
557 Convert* conv = value->as_Convert();
558 if (conv) {
559 switch (conv->op()) {
560 case Bytecodes::_i2b: type = T_BYTE; break;
561 case Bytecodes::_i2s: type = T_SHORT; break;
562 case Bytecodes::_i2c: type = T_CHAR; break;
563 }
564 }
565 }
566 }
567 if (type != T_ILLEGAL) {
568 switch (x->op()) {
569 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
570 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
571 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
572 }
573 } else {
574 Op2* op2 = x->value()->as_Op2();
575 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
576 jint safebits = 0;
577 jint mask = op2->y()->type()->as_IntConstant()->value();
578 switch (x->op()) {
579 case Bytecodes::_i2b: safebits = 0x7f; break;
580 case Bytecodes::_i2s: safebits = 0x7fff; break;
581 case Bytecodes::_i2c: safebits = 0xffff; break;
582 }
583 // When casting a masked integer to a smaller signed type, if
584 // the mask doesn't include the sign bit the cast isn't needed.
585 if (safebits && (mask & ~safebits) == 0) {
586 set_canonical(x->value());
587 }
588 }
589 }
590
591 }
592
593 void Canonicalizer::do_NullCheck (NullCheck* x) {
594 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
595 set_canonical(x->obj());
596 } else {
597 Constant* con = x->obj()->as_Constant();
598 if (con) {
599 ObjectType* c = con->type()->as_ObjectType();
600 if (c && c->is_loaded()) {
601 ObjectConstant* oc = c->as_ObjectConstant();
602 if (!oc || !oc->value()->is_null_object()) {
603 set_canonical(con);
604 }
605 }
606 }
607 }
608 }
609
610 void Canonicalizer::do_TypeCast (TypeCast* x) {}
611 void Canonicalizer::do_Invoke (Invoke* x) {}
612 void Canonicalizer::do_NewInstance (NewInstance* x) {}
613 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
614 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
615 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
616 void Canonicalizer::do_CheckCast (CheckCast* x) {
617 if (x->klass()->is_loaded()) {
618 Value obj = x->obj();
619 ciType* klass = obj->exact_type();
620 if (klass == NULL) klass = obj->declared_type();
621 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
622 set_canonical(obj);
623 return;
624 }
625 // checkcast of null returns null
626 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
627 set_canonical(obj);
628 }
629 }
630 }
631 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
632 if (x->klass()->is_loaded()) {
633 Value obj = x->obj();
634 ciType* exact = obj->exact_type();
635 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
636 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
637 return;
638 }
639 // instanceof null returns false
640 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
641 set_constant(0);
642 }
643 }
644
645 }
646 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
647 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
648 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
649 void Canonicalizer::do_Goto (Goto* x) {}
650
651
652 static bool is_true(jlong x, If::Condition cond, jlong y) {
653 switch (cond) {
654 case If::eql: return x == y;
655 case If::neq: return x != y;
656 case If::lss: return x < y;
657 case If::leq: return x <= y;
658 case If::gtr: return x > y;
659 case If::geq: return x >= y;
660 }
661 ShouldNotReachHere();
662 return false;
663 }
664
665 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
666 // An Instruction with multiple successors, x, is replaced by a Goto
667 // to a single successor, sux. Is a safepoint check needed = was the
668 // instruction being replaced a safepoint and the single remaining
669 // successor a back branch?
670 return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
671 }
672
673 void Canonicalizer::do_If(If* x) {
674 // move const to right
675 if (x->x()->type()->is_constant()) x->swap_operands();
676 // simplify
677 const Value l = x->x(); ValueType* lt = l->type();
678 const Value r = x->y(); ValueType* rt = r->type();
679
680 if (l == r && !lt->is_float_kind()) {
681 // pattern: If (a cond a) => simplify to Goto
682 BlockBegin* sux = NULL;
683 switch (x->cond()) {
684 case If::eql: sux = x->sux_for(true); break;
685 case If::neq: sux = x->sux_for(false); break;
686 case If::lss: sux = x->sux_for(false); break;
687 case If::leq: sux = x->sux_for(true); break;
688 case If::gtr: sux = x->sux_for(false); break;
689 case If::geq: sux = x->sux_for(true); break;
690 default: ShouldNotReachHere();
691 }
692 // If is a safepoint then the debug information should come from the state_before of the If.
693 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
694 return;
695 }
696
697 if (lt->is_constant() && rt->is_constant()) {
698 if (x->x()->as_Constant() != NULL) {
699 // pattern: If (lc cond rc) => simplify to: Goto
700 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
701 x->sux_for(true),
702 x->sux_for(false));
703 if (sux != NULL) {
704 // If is a safepoint then the debug information should come from the state_before of the If.
705 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
706 }
707 }
708 } else if (rt->as_IntConstant() != NULL) {
709 // pattern: If (l cond rc) => investigate further
710 const jint rc = rt->as_IntConstant()->value();
711 if (l->as_CompareOp() != NULL) {
712 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
713 CompareOp* cmp = l->as_CompareOp();
714 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
715 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
716 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
717 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
718 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
719 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
720 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
721 // lss_sux or gtr_sux.
722 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
723 // all successors identical => simplify to: Goto
724 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
725 } else {
726 // two successors differ and two successors are the same => simplify to: If (x cmp y)
727 // determine new condition & successors
728 If::Condition cond = If::eql;
729 BlockBegin* tsux = NULL;
730 BlockBegin* fsux = NULL;
731 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
732 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
733 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
734 else { ShouldNotReachHere(); }
735 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
736 if (cmp->x() == cmp->y()) {
737 do_If(canon);
738 } else {
739 if (compilation()->profile_branches()) {
740 // TODO: If profiling, leave floating point comparisons unoptimized.
741 // We currently do not support profiling of the unordered case.
742 switch(cmp->op()) {
743 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
744 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
745 set_canonical(x);
746 return;
747 }
748 }
749 set_bci(cmp->state_before()->bci());
750 set_canonical(canon);
751 }
752 }
753 } else if (l->as_InstanceOf() != NULL) {
754 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
755 // instruction in the graph (it is pinned). Need to fix this at some point.
756 // It should also be left in the graph when generating a profiled method version or Goto
757 // has to know that it was an InstanceOf.
758 return;
759 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
760 InstanceOf* inst = l->as_InstanceOf();
761 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
762 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
763 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
764 // both successors identical and klass is loaded => simplify to: Goto
765 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
766 } else {
767 // successors differ => simplify to: IfInstanceOf
768 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
769 }
770 }
771 } else if (rt == objectNull &&
772 (l->as_NewInstance() || l->as_NewArray() ||
773 (l->as_Local() && l->as_Local()->is_receiver()))) {
774 if (x->cond() == Instruction::eql) {
775 BlockBegin* sux = x->fsux();
776 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
777 } else {
778 assert(x->cond() == Instruction::neq, "only other valid case");
779 BlockBegin* sux = x->tsux();
780 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
781 }
782 }
783 }
784
785
786 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
787 if (x->tag()->type()->is_constant()) {
788 int v = x->tag()->type()->as_IntConstant()->value();
789 BlockBegin* sux = x->default_sux();
790 if (v >= x->lo_key() && v <= x->hi_key()) {
791 sux = x->sux_at(v - x->lo_key());
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->lo_key() == x->hi_key(), "keys must be the same");
809 Constant* key = new Constant(new IntConstant(x->lo_key()));
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_LookupSwitch(LookupSwitch* x) {
816 if (x->tag()->type()->is_constant()) {
817 int v = x->tag()->type()->as_IntConstant()->value();
818 BlockBegin* sux = x->default_sux();
819 for (int i = 0; i < x->length(); i++) {
820 if (v == x->key_at(i)) {
821 sux = x->sux_at(i);
822 }
823 }
824 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
825 } else if (x->number_of_sux() == 1) {
826 // NOTE: Code permanently disabled for now since the switch statement's
827 // tag expression may produce side-effects in which case it must
828 // be executed.
829 return;
830 // simplify to Goto
831 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
832 } else if (x->number_of_sux() == 2) {
833 // NOTE: Code permanently disabled for now since it produces two new nodes
834 // (Constant & If) and the Canonicalizer cannot return them correctly
835 // yet. For now we copied the corresponding code directly into the
836 // GraphBuilder (i.e., we should never reach here).
837 return;
838 // simplify to If
839 assert(x->length() == 1, "length must be the same");
840 Constant* key = new Constant(new IntConstant(x->key_at(0)));
841 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
842 }
843 }
844
845
846 void Canonicalizer::do_Return (Return* x) {}
847 void Canonicalizer::do_Throw (Throw* x) {}
848 void Canonicalizer::do_Base (Base* x) {}
849 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
850 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
851
852 static bool match_index_and_scale(Instruction* instr,
853 Instruction** index,
854 int* log2_scale) {
855 // Skip conversion ops. This works only on 32bit because of the implicit l2i that the
856 // unsafe performs.
857 #ifndef _LP64
858 Convert* convert = instr->as_Convert();
859 if (convert != NULL && convert->op() == Bytecodes::_i2l) {
860 assert(convert->value()->type() == intType, "invalid input type");
861 instr = convert->value();
862 }
863 #endif
864
865 ShiftOp* shift = instr->as_ShiftOp();
866 if (shift != NULL) {
867 if (shift->op() == Bytecodes::_lshl) {
868 assert(shift->x()->type() == longType, "invalid input type");
869 } else {
870 #ifndef _LP64
871 if (shift->op() == Bytecodes::_ishl) {
872 assert(shift->x()->type() == intType, "invalid input type");
873 } else {
874 return false;
875 }
876 #else
877 return false;
878 #endif
879 }
880
881
882 // Constant shift value?
883 Constant* con = shift->y()->as_Constant();
884 if (con == NULL) return false;
885 // Well-known type and value?
886 IntConstant* val = con->type()->as_IntConstant();
887 assert(val != NULL, "Should be an int constant");
888
889 *index = shift->x();
890 int tmp_scale = val->value();
891 if (tmp_scale >= 0 && tmp_scale < 4) {
892 *log2_scale = tmp_scale;
893 return true;
894 } else {
895 return false;
896 }
897 }
898
899 ArithmeticOp* arith = instr->as_ArithmeticOp();
900 if (arith != NULL) {
901 // See if either arg is a known constant
902 Constant* con = arith->x()->as_Constant();
903 if (con != NULL) {
904 *index = arith->y();
905 } else {
906 con = arith->y()->as_Constant();
907 if (con == NULL) return false;
908 *index = arith->x();
909 }
910 long const_value;
911 // Check for integer multiply
912 if (arith->op() == Bytecodes::_lmul) {
913 assert((*index)->type() == longType, "invalid input type");
914 LongConstant* val = con->type()->as_LongConstant();
915 assert(val != NULL, "expecting a long constant");
916 const_value = val->value();
917 } else {
918 #ifndef _LP64
919 if (arith->op() == Bytecodes::_imul) {
920 assert((*index)->type() == intType, "invalid input type");
921 IntConstant* val = con->type()->as_IntConstant();
922 assert(val != NULL, "expecting an int constant");
923 const_value = val->value();
924 } else {
925 return false;
926 }
927 #else
928 return false;
929 #endif
930 }
931 switch (const_value) {
932 case 1: *log2_scale = 0; return true;
933 case 2: *log2_scale = 1; return true;
934 case 4: *log2_scale = 2; return true;
935 case 8: *log2_scale = 3; return true;
936 default: return false;
937 }
938 }
939
940 // Unknown instruction sequence; don't touch it
941 return false;
942 }
943
944
945 static bool match(UnsafeRawOp* x,
946 Instruction** base,
947 Instruction** index,
948 int* log2_scale) {
949 ArithmeticOp* root = x->base()->as_ArithmeticOp();
950 if (root == NULL) return false;
951 // Limit ourselves to addition for now
952 if (root->op() != Bytecodes::_ladd) return false;
953
954 bool match_found = false;
955 // Try to find shift or scale op
956 if (match_index_and_scale(root->y(), index, log2_scale)) {
957 *base = root->x();
958 match_found = true;
959 } else if (match_index_and_scale(root->x(), index, log2_scale)) {
960 *base = root->y();
961 match_found = true;
962 } else if (NOT_LP64(root->y()->as_Convert() != NULL) LP64_ONLY(false)) {
963 // Skipping i2l works only on 32bit because of the implicit l2i that the unsafe performs.
964 // 64bit needs a real sign-extending conversion.
965 Convert* convert = root->y()->as_Convert();
966 if (convert->op() == Bytecodes::_i2l) {
967 assert(convert->value()->type() == intType, "should be an int");
968 // pick base and index, setting scale at 1
969 *base = root->x();
970 *index = convert->value();
971 *log2_scale = 0;
972 match_found = true;
973 }
974 }
975 // The default solution
976 if (!match_found) {
977 *base = root->x();
978 *index = root->y();
979 *log2_scale = 0;
980 }
981
982 // If the value is pinned then it will be always be computed so
983 // there's no profit to reshaping the expression.
984 return !root->is_pinned();
985 }
986
987
988 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
989 Instruction* base = NULL;
990 Instruction* index = NULL;
991 int log2_scale;
992
993 if (match(x, &base, &index, &log2_scale)) {
994 x->set_base(base);
995 x->set_index(index);
996 x->set_log2_scale(log2_scale);
997 if (PrintUnsafeOptimization) {
998 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
999 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
1000 }
1001 }
1002 }
1003
1004 void Canonicalizer::do_RoundFP(RoundFP* x) {}
1005 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
1006 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
1007 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
1008 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
1009 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
1010 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
1011 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
1012 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
1013 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}
1014 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
1015 #ifdef ASSERT
1016 void Canonicalizer::do_Assert(Assert* x) {}
1017 #endif
1018 void Canonicalizer::do_MemBar(MemBar* x) {}