1 /*
   2  * Copyright (c) 1999, 2016, 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* array = x->array()->as_NewArray();
 226   if (array != NULL && array->length() != NULL) {
 227     Constant* length = array->length()->as_Constant();
 228     if (length != NULL) {
 229       // do not use the Constant itself, but create a new Constant
 230       // with same value Otherwise a Constant is live over multiple
 231       // blocks without being registered in a state array.
 232       assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
 233       set_constant(length->type()->as_IntConstant()->value());
 234     }
 235   } else {
 236     LoadField* lf = x->array()->as_LoadField();
 237     if (lf != NULL) {
 238       ciField* field = lf->field();
 239       if (field->is_constant() && field->is_static()) {
 240         // final static field
 241         ciObject* c = field->constant_value().as_object();
 242         if (c->is_array()) {
 243           ciArray* array = (ciArray*) c;
 244           set_constant(array->length());
 245         }
 246       }
 247     }
 248   }
 249 }
 250 
 251 void Canonicalizer::do_LoadIndexed    (LoadIndexed*     x) {}
 252 void Canonicalizer::do_StoreIndexed   (StoreIndexed*    x) {
 253   // If a value is going to be stored into a field or array some of
 254   // the conversions emitted by javac are unneeded because the fields
 255   // are packed to their natural size.
 256   Convert* conv = x->value()->as_Convert();
 257   if (conv) {
 258     Value value = NULL;
 259     BasicType type = x->elt_type();
 260     switch (conv->op()) {
 261     case Bytecodes::_i2b: if (type == T_BYTE)  value = conv->value(); break;
 262     case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
 263     case Bytecodes::_i2c: if (type == T_CHAR  || type == T_BYTE) value = conv->value(); break;
 264     }
 265     // limit this optimization to current block
 266     if (value != NULL && in_current_block(conv)) {
 267       set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
 268                                      x->elt_type(), value, x->state_before(),
 269                                      x->check_boolean()));
 270       return;
 271     }
 272   }
 273 
 274 
 275 }
 276 
 277 
 278 void Canonicalizer::do_NegateOp(NegateOp* x) {
 279   ValueType* t = x->x()->type();
 280   if (t->is_constant()) {
 281     switch (t->tag()) {
 282       case intTag   : set_constant(-t->as_IntConstant   ()->value()); return;
 283       case longTag  : set_constant(-t->as_LongConstant  ()->value()); return;
 284       case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
 285       case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
 286       default       : ShouldNotReachHere();
 287     }
 288   }
 289 }
 290 
 291 
 292 void Canonicalizer::do_ArithmeticOp   (ArithmeticOp*    x) { do_Op2(x); }
 293 
 294 
 295 void Canonicalizer::do_ShiftOp        (ShiftOp*         x) {
 296   ValueType* t = x->x()->type();
 297   ValueType* t2 = x->y()->type();
 298   if (t->is_constant()) {
 299     switch (t->tag()) {
 300     case intTag   : if (t->as_IntConstant()->value() == 0)         { set_constant(0); return; } break;
 301     case longTag  : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
 302     default       : ShouldNotReachHere();
 303     }
 304     if (t2->is_constant()) {
 305       if (t->tag() == intTag) {
 306         int value = t->as_IntConstant()->value();
 307         int shift = t2->as_IntConstant()->value() & 31;
 308         jint mask = ~(~0 << (32 - shift));
 309         if (shift == 0) mask = ~0;
 310         switch (x->op()) {
 311           case Bytecodes::_ishl:  set_constant(value << shift); return;
 312           case Bytecodes::_ishr:  set_constant(value >> shift); return;
 313           case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
 314         }
 315       } else if (t->tag() == longTag) {
 316         jlong value = t->as_LongConstant()->value();
 317         int shift = t2->as_IntConstant()->value() & 63;
 318         jlong mask = ~(~jlong_cast(0) << (64 - shift));
 319         if (shift == 0) mask = ~jlong_cast(0);
 320         switch (x->op()) {
 321           case Bytecodes::_lshl:  set_constant(value << shift); return;
 322           case Bytecodes::_lshr:  set_constant(value >> shift); return;
 323           case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
 324         }
 325       }
 326     }
 327   }
 328   if (t2->is_constant()) {
 329     switch (t2->tag()) {
 330       case intTag   : if (t2->as_IntConstant()->value() == 0)  set_canonical(x->x()); return;
 331       case longTag  : if (t2->as_LongConstant()->value() == (jlong)0)  set_canonical(x->x()); return;
 332       default       : ShouldNotReachHere();
 333     }
 334   }
 335 }
 336 
 337 
 338 void Canonicalizer::do_LogicOp        (LogicOp*         x) { do_Op2(x); }
 339 void Canonicalizer::do_CompareOp      (CompareOp*       x) {
 340   if (x->x() == x->y()) {
 341     switch (x->x()->type()->tag()) {
 342       case longTag: set_constant(0); break;
 343       case floatTag: {
 344         FloatConstant* fc = x->x()->type()->as_FloatConstant();
 345         if (fc) {
 346           if (g_isnan(fc->value())) {
 347             set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
 348           } else {
 349             set_constant(0);
 350           }
 351         }
 352         break;
 353       }
 354       case doubleTag: {
 355         DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
 356         if (dc) {
 357           if (g_isnan(dc->value())) {
 358             set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
 359           } else {
 360             set_constant(0);
 361           }
 362         }
 363         break;
 364       }
 365     }
 366   } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
 367     switch (x->x()->type()->tag()) {
 368       case longTag: {
 369         jlong vx = x->x()->type()->as_LongConstant()->value();
 370         jlong vy = x->y()->type()->as_LongConstant()->value();
 371         if (vx == vy)
 372           set_constant(0);
 373         else if (vx < vy)
 374           set_constant(-1);
 375         else
 376           set_constant(1);
 377         break;
 378       }
 379 
 380       case floatTag: {
 381         float vx = x->x()->type()->as_FloatConstant()->value();
 382         float vy = x->y()->type()->as_FloatConstant()->value();
 383         if (g_isnan(vx) || g_isnan(vy))
 384           set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
 385         else if (vx == vy)
 386           set_constant(0);
 387         else if (vx < vy)
 388           set_constant(-1);
 389         else
 390           set_constant(1);
 391         break;
 392       }
 393 
 394       case doubleTag: {
 395         double vx = x->x()->type()->as_DoubleConstant()->value();
 396         double vy = x->y()->type()->as_DoubleConstant()->value();
 397         if (g_isnan(vx) || g_isnan(vy))
 398           set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
 399         else if (vx == vy)
 400           set_constant(0);
 401         else if (vx < vy)
 402           set_constant(-1);
 403         else
 404           set_constant(1);
 405         break;
 406       }
 407     }
 408 
 409   }
 410 }
 411 
 412 
 413 void Canonicalizer::do_IfInstanceOf(IfInstanceOf*    x) {}
 414 
 415 void Canonicalizer::do_IfOp(IfOp* x) {
 416   // Caution: do not use do_Op2(x) here for now since
 417   //          we map the condition to the op for now!
 418   move_const_to_right(x);
 419 }
 420 
 421 
 422 void Canonicalizer::do_Intrinsic      (Intrinsic*       x) {
 423   switch (x->id()) {
 424   case vmIntrinsics::_floatToRawIntBits   : {
 425     FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
 426     if (c != NULL) {
 427       JavaValue v;
 428       v.set_jfloat(c->value());
 429       set_constant(v.get_jint());
 430     }
 431     break;
 432   }
 433   case vmIntrinsics::_intBitsToFloat      : {
 434     IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
 435     if (c != NULL) {
 436       JavaValue v;
 437       v.set_jint(c->value());
 438       set_constant(v.get_jfloat());
 439     }
 440     break;
 441   }
 442   case vmIntrinsics::_doubleToRawLongBits : {
 443     DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
 444     if (c != NULL) {
 445       JavaValue v;
 446       v.set_jdouble(c->value());
 447       set_constant(v.get_jlong());
 448     }
 449     break;
 450   }
 451   case vmIntrinsics::_longBitsToDouble    : {
 452     LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
 453     if (c != NULL) {
 454       JavaValue v;
 455       v.set_jlong(c->value());
 456       set_constant(v.get_jdouble());
 457     }
 458     break;
 459   }
 460   case vmIntrinsics::_isInstance          : {
 461     assert(x->number_of_arguments() == 2, "wrong type");
 462 
 463     InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
 464     if (c != NULL && !c->value()->is_null_object()) {
 465       // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors
 466       ciType* t = c->value()->as_instance()->java_mirror_type();
 467       if (t->is_klass()) {
 468         // substitute cls.isInstance(obj) of a constant Class into
 469         // an InstantOf instruction
 470         InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before());
 471         set_canonical(i);
 472         // and try to canonicalize even further
 473         do_InstanceOf(i);
 474       } else {
 475         assert(t->is_primitive_type(), "should be a primitive type");
 476         // cls.isInstance(obj) always returns false for primitive classes
 477         set_constant(0);
 478       }
 479     }
 480     break;
 481   }
 482   }
 483 }
 484 
 485 void Canonicalizer::do_Convert        (Convert*         x) {
 486   if (x->value()->type()->is_constant()) {
 487     switch (x->op()) {
 488     case Bytecodes::_i2b:  set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
 489     case Bytecodes::_i2s:  set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
 490     case Bytecodes::_i2c:  set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
 491     case Bytecodes::_i2l:  set_constant((jlong)(x->value()->type()->as_IntConstant()->value()));             break;
 492     case Bytecodes::_i2f:  set_constant((float)(x->value()->type()->as_IntConstant()->value()));             break;
 493     case Bytecodes::_i2d:  set_constant((double)(x->value()->type()->as_IntConstant()->value()));            break;
 494     case Bytecodes::_l2i:  set_constant((int)(x->value()->type()->as_LongConstant()->value()));              break;
 495     case Bytecodes::_l2f:  set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
 496     case Bytecodes::_l2d:  set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
 497     case Bytecodes::_f2d:  set_constant((double)(x->value()->type()->as_FloatConstant()->value()));          break;
 498     case Bytecodes::_f2i:  set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
 499     case Bytecodes::_f2l:  set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
 500     case Bytecodes::_d2f:  set_constant((float)(x->value()->type()->as_DoubleConstant()->value()));          break;
 501     case Bytecodes::_d2i:  set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
 502     case Bytecodes::_d2l:  set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
 503     default:
 504       ShouldNotReachHere();
 505     }
 506   }
 507 
 508   Value value = x->value();
 509   BasicType type = T_ILLEGAL;
 510   LoadField* lf = value->as_LoadField();
 511   if (lf) {
 512     type = lf->field_type();
 513   } else {
 514     LoadIndexed* li = value->as_LoadIndexed();
 515     if (li) {
 516       type = li->elt_type();
 517     } else {
 518       Convert* conv = value->as_Convert();
 519       if (conv) {
 520         switch (conv->op()) {
 521           case Bytecodes::_i2b: type = T_BYTE;  break;
 522           case Bytecodes::_i2s: type = T_SHORT; break;
 523           case Bytecodes::_i2c: type = T_CHAR;  break;
 524         }
 525       }
 526     }
 527   }
 528   if (type != T_ILLEGAL) {
 529     switch (x->op()) {
 530       case Bytecodes::_i2b: if (type == T_BYTE)                    set_canonical(x->value()); break;
 531       case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
 532       case Bytecodes::_i2c: if (type == T_CHAR)                    set_canonical(x->value()); break;
 533     }
 534   } else {
 535     Op2* op2 = x->value()->as_Op2();
 536     if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
 537       jint safebits = 0;
 538       jint mask = op2->y()->type()->as_IntConstant()->value();
 539       switch (x->op()) {
 540         case Bytecodes::_i2b: safebits = 0x7f;   break;
 541         case Bytecodes::_i2s: safebits = 0x7fff; break;
 542         case Bytecodes::_i2c: safebits = 0xffff; break;
 543       }
 544       // When casting a masked integer to a smaller signed type, if
 545       // the mask doesn't include the sign bit the cast isn't needed.
 546       if (safebits && (mask & ~safebits) == 0) {
 547         set_canonical(x->value());
 548       }
 549     }
 550   }
 551 
 552 }
 553 
 554 void Canonicalizer::do_NullCheck      (NullCheck*       x) {
 555   if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
 556     set_canonical(x->obj());
 557   } else {
 558     Constant* con = x->obj()->as_Constant();
 559     if (con) {
 560       ObjectType* c = con->type()->as_ObjectType();
 561       if (c && c->is_loaded()) {
 562         ObjectConstant* oc = c->as_ObjectConstant();
 563         if (!oc || !oc->value()->is_null_object()) {
 564           set_canonical(con);
 565         }
 566       }
 567     }
 568   }
 569 }
 570 
 571 void Canonicalizer::do_TypeCast       (TypeCast*        x) {}
 572 void Canonicalizer::do_Invoke         (Invoke*          x) {}
 573 void Canonicalizer::do_NewInstance    (NewInstance*     x) {}
 574 void Canonicalizer::do_NewTypeArray   (NewTypeArray*    x) {}
 575 void Canonicalizer::do_NewObjectArray (NewObjectArray*  x) {}
 576 void Canonicalizer::do_NewMultiArray  (NewMultiArray*   x) {}
 577 void Canonicalizer::do_CheckCast      (CheckCast*       x) {
 578   if (x->klass()->is_loaded()) {
 579     Value obj = x->obj();
 580     ciType* klass = obj->exact_type();
 581     if (klass == NULL) klass = obj->declared_type();
 582     if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
 583       set_canonical(obj);
 584       return;
 585     }
 586     // checkcast of null returns null
 587     if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
 588       set_canonical(obj);
 589     }
 590   }
 591 }
 592 void Canonicalizer::do_InstanceOf     (InstanceOf*      x) {
 593   if (x->klass()->is_loaded()) {
 594     Value obj = x->obj();
 595     ciType* exact = obj->exact_type();
 596     if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
 597       set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
 598       return;
 599     }
 600     // instanceof null returns false
 601     if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
 602       set_constant(0);
 603     }
 604   }
 605 
 606 }
 607 void Canonicalizer::do_MonitorEnter   (MonitorEnter*    x) {}
 608 void Canonicalizer::do_MonitorExit    (MonitorExit*     x) {}
 609 void Canonicalizer::do_BlockBegin     (BlockBegin*      x) {}
 610 void Canonicalizer::do_Goto           (Goto*            x) {}
 611 
 612 
 613 static bool is_true(jlong x, If::Condition cond, jlong y) {
 614   switch (cond) {
 615     case If::eql: return x == y;
 616     case If::neq: return x != y;
 617     case If::lss: return x <  y;
 618     case If::leq: return x <= y;
 619     case If::gtr: return x >  y;
 620     case If::geq: return x >= y;
 621   }
 622   ShouldNotReachHere();
 623   return false;
 624 }
 625 
 626 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
 627   // An Instruction with multiple successors, x, is replaced by a Goto
 628   // to a single successor, sux. Is a safepoint check needed = was the
 629   // instruction being replaced a safepoint and the single remaining
 630   // successor a back branch?
 631   return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
 632 }
 633 
 634 void Canonicalizer::do_If(If* x) {
 635   // move const to right
 636   if (x->x()->type()->is_constant()) x->swap_operands();
 637   // simplify
 638   const Value l = x->x(); ValueType* lt = l->type();
 639   const Value r = x->y(); ValueType* rt = r->type();
 640 
 641   if (l == r && !lt->is_float_kind()) {
 642     // pattern: If (a cond a) => simplify to Goto
 643     BlockBegin* sux = NULL;
 644     switch (x->cond()) {
 645     case If::eql: sux = x->sux_for(true);  break;
 646     case If::neq: sux = x->sux_for(false); break;
 647     case If::lss: sux = x->sux_for(false); break;
 648     case If::leq: sux = x->sux_for(true);  break;
 649     case If::gtr: sux = x->sux_for(false); break;
 650     case If::geq: sux = x->sux_for(true);  break;
 651     default: ShouldNotReachHere();
 652     }
 653     // If is a safepoint then the debug information should come from the state_before of the If.
 654     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 655     return;
 656   }
 657 
 658   if (lt->is_constant() && rt->is_constant()) {
 659     if (x->x()->as_Constant() != NULL) {
 660       // pattern: If (lc cond rc) => simplify to: Goto
 661       BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
 662                                                        x->sux_for(true),
 663                                                        x->sux_for(false));
 664       if (sux != NULL) {
 665         // If is a safepoint then the debug information should come from the state_before of the If.
 666         set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 667       }
 668     }
 669   } else if (rt->as_IntConstant() != NULL) {
 670     // pattern: If (l cond rc) => investigate further
 671     const jint rc = rt->as_IntConstant()->value();
 672     if (l->as_CompareOp() != NULL) {
 673       // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
 674       CompareOp* cmp = l->as_CompareOp();
 675       bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
 676       BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
 677       BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
 678       BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
 679       BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
 680       // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
 681       //       equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
 682       //       lss_sux or gtr_sux.
 683       if (lss_sux == eql_sux && eql_sux == gtr_sux) {
 684         // all successors identical => simplify to: Goto
 685         set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
 686       } else {
 687         // two successors differ and two successors are the same => simplify to: If (x cmp y)
 688         // determine new condition & successors
 689         If::Condition cond = If::eql;
 690         BlockBegin* tsux = NULL;
 691         BlockBegin* fsux = NULL;
 692              if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
 693         else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
 694         else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
 695         else                         { ShouldNotReachHere();                           }
 696         If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
 697         if (cmp->x() == cmp->y()) {
 698           do_If(canon);
 699         } else {
 700           if (compilation()->profile_branches()) {
 701             // TODO: If profiling, leave floating point comparisons unoptimized.
 702             // We currently do not support profiling of the unordered case.
 703             switch(cmp->op()) {
 704               case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
 705               case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
 706                 set_canonical(x);
 707                 return;
 708             }
 709           }
 710           set_bci(cmp->state_before()->bci());
 711           set_canonical(canon);
 712         }
 713       }
 714     } else if (l->as_InstanceOf() != NULL) {
 715       // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
 716       //       instruction in the graph (it is pinned). Need to fix this at some point.
 717       //       It should also be left in the graph when generating a profiled method version or Goto
 718       //       has to know that it was an InstanceOf.
 719       return;
 720       // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
 721       InstanceOf* inst = l->as_InstanceOf();
 722       BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
 723       BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
 724       if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
 725         // both successors identical and klass is loaded => simplify to: Goto
 726         set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
 727       } else {
 728         // successors differ => simplify to: IfInstanceOf
 729         set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
 730       }
 731     }
 732   } else if (rt == objectNull && (l->as_NewInstance() || l->as_NewArray())) {
 733     if (x->cond() == Instruction::eql) {
 734       BlockBegin* sux = x->fsux();
 735       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 736     } else {
 737       assert(x->cond() == Instruction::neq, "only other valid case");
 738       BlockBegin* sux = x->tsux();
 739       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 740     }
 741   }
 742 }
 743 
 744 
 745 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
 746   if (x->tag()->type()->is_constant()) {
 747     int v = x->tag()->type()->as_IntConstant()->value();
 748     BlockBegin* sux = x->default_sux();
 749     if (v >= x->lo_key() && v <= x->hi_key()) {
 750       sux = x->sux_at(v - x->lo_key());
 751     }
 752     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 753   } else if (x->number_of_sux() == 1) {
 754     // NOTE: Code permanently disabled for now since the switch statement's
 755     //       tag expression may produce side-effects in which case it must
 756     //       be executed.
 757     return;
 758     // simplify to Goto
 759     set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
 760   } else if (x->number_of_sux() == 2) {
 761     // NOTE: Code permanently disabled for now since it produces two new nodes
 762     //       (Constant & If) and the Canonicalizer cannot return them correctly
 763     //       yet. For now we copied the corresponding code directly into the
 764     //       GraphBuilder (i.e., we should never reach here).
 765     return;
 766     // simplify to If
 767     assert(x->lo_key() == x->hi_key(), "keys must be the same");
 768     Constant* key = new Constant(new IntConstant(x->lo_key()));
 769     set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
 770   }
 771 }
 772 
 773 
 774 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
 775   if (x->tag()->type()->is_constant()) {
 776     int v = x->tag()->type()->as_IntConstant()->value();
 777     BlockBegin* sux = x->default_sux();
 778     for (int i = 0; i < x->length(); i++) {
 779       if (v == x->key_at(i)) {
 780         sux = x->sux_at(i);
 781       }
 782     }
 783     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 784   } else if (x->number_of_sux() == 1) {
 785     // NOTE: Code permanently disabled for now since the switch statement's
 786     //       tag expression may produce side-effects in which case it must
 787     //       be executed.
 788     return;
 789     // simplify to Goto
 790     set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
 791   } else if (x->number_of_sux() == 2) {
 792     // NOTE: Code permanently disabled for now since it produces two new nodes
 793     //       (Constant & If) and the Canonicalizer cannot return them correctly
 794     //       yet. For now we copied the corresponding code directly into the
 795     //       GraphBuilder (i.e., we should never reach here).
 796     return;
 797     // simplify to If
 798     assert(x->length() == 1, "length must be the same");
 799     Constant* key = new Constant(new IntConstant(x->key_at(0)));
 800     set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
 801   }
 802 }
 803 
 804 
 805 void Canonicalizer::do_Return         (Return*          x) {}
 806 void Canonicalizer::do_Throw          (Throw*           x) {}
 807 void Canonicalizer::do_Base           (Base*            x) {}
 808 void Canonicalizer::do_OsrEntry       (OsrEntry*        x) {}
 809 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
 810 
 811 static bool match_index_and_scale(Instruction*  instr,
 812                                   Instruction** index,
 813                                   int*          log2_scale) {
 814   // Skip conversion ops. This works only on 32bit because of the implicit l2i that the
 815   // unsafe performs.
 816 #ifndef _LP64
 817   Convert* convert = instr->as_Convert();
 818   if (convert != NULL && convert->op() == Bytecodes::_i2l) {
 819     assert(convert->value()->type() == intType, "invalid input type");
 820     instr = convert->value();
 821   }
 822 #endif
 823 
 824   ShiftOp* shift = instr->as_ShiftOp();
 825   if (shift != NULL) {
 826     if (shift->op() == Bytecodes::_lshl) {
 827       assert(shift->x()->type() == longType, "invalid input type");
 828     } else {
 829 #ifndef _LP64
 830       if (shift->op() == Bytecodes::_ishl) {
 831         assert(shift->x()->type() == intType, "invalid input type");
 832       } else {
 833         return false;
 834       }
 835 #else
 836       return false;
 837 #endif
 838     }
 839 
 840 
 841     // Constant shift value?
 842     Constant* con = shift->y()->as_Constant();
 843     if (con == NULL) return false;
 844     // Well-known type and value?
 845     IntConstant* val = con->type()->as_IntConstant();
 846     assert(val != NULL, "Should be an int constant");
 847 
 848     *index = shift->x();
 849     int tmp_scale = val->value();
 850     if (tmp_scale >= 0 && tmp_scale < 4) {
 851       *log2_scale = tmp_scale;
 852       return true;
 853     } else {
 854       return false;
 855     }
 856   }
 857 
 858   ArithmeticOp* arith = instr->as_ArithmeticOp();
 859   if (arith != NULL) {
 860     // See if either arg is a known constant
 861     Constant* con = arith->x()->as_Constant();
 862     if (con != NULL) {
 863       *index = arith->y();
 864     } else {
 865       con = arith->y()->as_Constant();
 866       if (con == NULL) return false;
 867       *index = arith->x();
 868     }
 869     long const_value;
 870     // Check for integer multiply
 871     if (arith->op() == Bytecodes::_lmul) {
 872       assert((*index)->type() == longType, "invalid input type");
 873       LongConstant* val = con->type()->as_LongConstant();
 874       assert(val != NULL, "expecting a long constant");
 875       const_value = val->value();
 876     } else {
 877 #ifndef _LP64
 878       if (arith->op() == Bytecodes::_imul) {
 879         assert((*index)->type() == intType, "invalid input type");
 880         IntConstant* val = con->type()->as_IntConstant();
 881         assert(val != NULL, "expecting an int constant");
 882         const_value = val->value();
 883       } else {
 884         return false;
 885       }
 886 #else
 887       return false;
 888 #endif
 889     }
 890     switch (const_value) {
 891     case 1: *log2_scale = 0; return true;
 892     case 2: *log2_scale = 1; return true;
 893     case 4: *log2_scale = 2; return true;
 894     case 8: *log2_scale = 3; return true;
 895     default:            return false;
 896     }
 897   }
 898 
 899   // Unknown instruction sequence; don't touch it
 900   return false;
 901 }
 902 
 903 
 904 static bool match(UnsafeRawOp* x,
 905                   Instruction** base,
 906                   Instruction** index,
 907                   int*          log2_scale) {
 908   ArithmeticOp* root = x->base()->as_ArithmeticOp();
 909   if (root == NULL) return false;
 910   // Limit ourselves to addition for now
 911   if (root->op() != Bytecodes::_ladd) return false;
 912 
 913   bool match_found = false;
 914   // Try to find shift or scale op
 915   if (match_index_and_scale(root->y(), index, log2_scale)) {
 916     *base = root->x();
 917     match_found = true;
 918   } else if (match_index_and_scale(root->x(), index, log2_scale)) {
 919     *base = root->y();
 920     match_found = true;
 921   } else if (NOT_LP64(root->y()->as_Convert() != NULL) LP64_ONLY(false)) {
 922     // Skipping i2l works only on 32bit because of the implicit l2i that the unsafe performs.
 923     // 64bit needs a real sign-extending conversion.
 924     Convert* convert = root->y()->as_Convert();
 925     if (convert->op() == Bytecodes::_i2l) {
 926       assert(convert->value()->type() == intType, "should be an int");
 927       // pick base and index, setting scale at 1
 928       *base  = root->x();
 929       *index = convert->value();
 930       *log2_scale = 0;
 931       match_found = true;
 932     }
 933   }
 934   // The default solution
 935   if (!match_found) {
 936     *base = root->x();
 937     *index = root->y();
 938     *log2_scale = 0;
 939   }
 940 
 941   // If the value is pinned then it will be always be computed so
 942   // there's no profit to reshaping the expression.
 943   return !root->is_pinned();
 944 }
 945 
 946 
 947 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
 948   Instruction* base = NULL;
 949   Instruction* index = NULL;
 950   int          log2_scale;
 951 
 952   if (match(x, &base, &index, &log2_scale)) {
 953     x->set_base(base);
 954     x->set_index(index);
 955     x->set_log2_scale(log2_scale);
 956     if (PrintUnsafeOptimization) {
 957       tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
 958                     x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
 959     }
 960   }
 961 }
 962 
 963 void Canonicalizer::do_RoundFP(RoundFP* x) {}
 964 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
 965 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
 966 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
 967 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
 968 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
 969 void Canonicalizer::do_UnsafePrefetchRead (UnsafePrefetchRead*  x) {}
 970 void Canonicalizer::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
 971 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
 972 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
 973 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
 974 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}
 975 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
 976 #ifdef ASSERT
 977 void Canonicalizer::do_Assert(Assert* x) {}
 978 #endif
 979 void Canonicalizer::do_MemBar(MemBar* x) {}