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src/hotspot/share/c1/c1_Canonicalizer.cpp

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264     ciField* field = lf->field();
265     if (field->is_static_constant()) {
266       // Constant field loads are usually folded during parsing.
267       // But it doesn't happen with PatchALot, ScavengeRootsInCode < 2, or when
268       // holder class is being initialized during parsing (for static fields).
269       ciObject* c = field->constant_value().as_object();
270       if (!c->is_null_object()) {
271         set_constant(c->as_array()->length());
272       }
273     }
274   }
275 }
276 
277 void Canonicalizer::do_LoadIndexed    (LoadIndexed*     x) {
278   StableArrayConstant* array = x->array()->type()->as_StableArrayConstant();
279   IntConstant* index = x->index()->type()->as_IntConstant();
280 
281   assert(array == NULL || FoldStableValues, "not enabled");
282 
283   // Constant fold loads from stable arrays.
284   if (!x->mismatched() && array != NULL && index != NULL) {
285     jint idx = index->value();
286     if (idx < 0 || idx >= array->value()->length()) {
287       // Leave the load as is. The range check will handle it.
288       return;
289     }
290 
291     ciConstant field_val = array->value()->element_value(idx);
292     if (!field_val.is_null_or_zero()) {
293       jint dimension = array->dimension();
294       assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info");
295       ValueType* value = NULL;
296       if (dimension > 1) {
297         // Preserve information about the dimension for the element.
298         assert(field_val.as_object()->is_array(), "not an array");
299         value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1);
300       } else {
301         assert(dimension == 1, "sanity");
302         value = as_ValueType(field_val);
303       }
304       set_canonical(new Constant(value));

623     if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
624       jint safebits = 0;
625       jint mask = op2->y()->type()->as_IntConstant()->value();
626       switch (x->op()) {
627         case Bytecodes::_i2b: safebits = 0x7f;   break;
628         case Bytecodes::_i2s: safebits = 0x7fff; break;
629         case Bytecodes::_i2c: safebits = 0xffff; break;
630         default             :                    break;
631       }
632       // When casting a masked integer to a smaller signed type, if
633       // the mask doesn't include the sign bit the cast isn't needed.
634       if (safebits && (mask & ~safebits) == 0) {
635         set_canonical(x->value());
636       }
637     }
638   }
639 
640 }
641 
642 void Canonicalizer::do_NullCheck      (NullCheck*       x) {
643   if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
644     set_canonical(x->obj());
645   } else {
646     Constant* con = x->obj()->as_Constant();
647     if (con) {
648       ObjectType* c = con->type()->as_ObjectType();
649       if (c && c->is_loaded()) {
650         ObjectConstant* oc = c->as_ObjectConstant();
651         if (!oc || !oc->value()->is_null_object()) {
652           set_canonical(con);
653         }
654       }
655     }
656   }
657 }
658 
659 void Canonicalizer::do_TypeCast       (TypeCast*        x) {}
660 void Canonicalizer::do_Invoke         (Invoke*          x) {}
661 void Canonicalizer::do_NewInstance    (NewInstance*     x) {}

662 void Canonicalizer::do_NewTypeArray   (NewTypeArray*    x) {}
663 void Canonicalizer::do_NewObjectArray (NewObjectArray*  x) {}
664 void Canonicalizer::do_NewMultiArray  (NewMultiArray*   x) {}

665 void Canonicalizer::do_CheckCast      (CheckCast*       x) {
666   if (x->klass()->is_loaded()) {
667     Value obj = x->obj();
668     ciType* klass = obj->exact_type();
669     if (klass == NULL) {
670       klass = obj->declared_type();
671     }
672     if (klass != NULL && klass->is_loaded()) {
673       bool is_interface = klass->is_instance_klass() &&
674                           klass->as_instance_klass()->is_interface();
675       // Interface casts can't be statically optimized away since verifier doesn't
676       // enforce interface types in bytecode.
677       if (!is_interface && klass->is_subtype_of(x->klass())) {

678         set_canonical(obj);
679         return;
680       }
681     }
682     // checkcast of null returns null
683     if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
684       set_canonical(obj);
685     }
686   }
687 }
688 void Canonicalizer::do_InstanceOf     (InstanceOf*      x) {
689   if (x->klass()->is_loaded()) {
690     Value obj = x->obj();
691     ciType* exact = obj->exact_type();
692     if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
693       set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
694       return;
695     }
696     // instanceof null returns false
697     if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
698       set_constant(0);
699     }
700   }
701 
702 }
703 void Canonicalizer::do_MonitorEnter   (MonitorEnter*    x) {}
704 void Canonicalizer::do_MonitorExit    (MonitorExit*     x) {}
705 void Canonicalizer::do_BlockBegin     (BlockBegin*      x) {}
706 void Canonicalizer::do_Goto           (Goto*            x) {}
707 
708 
709 static bool is_true(jlong x, If::Condition cond, jlong y) {
710   switch (cond) {
711     case If::eql: return x == y;
712     case If::neq: return x != y;
713     case If::lss: return x <  y;
714     case If::leq: return x <= y;
715     case If::gtr: return x >  y;
716     case If::geq: return x >= y;
717     default:

795           do_If(canon);
796         } else {
797           if (compilation()->profile_branches() || compilation()->is_profiling()) {
798             // TODO: If profiling, leave floating point comparisons unoptimized.
799             // We currently do not support profiling of the unordered case.
800             switch(cmp->op()) {
801               case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
802               case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
803                 set_canonical(x);
804                 return;
805               default:
806                 break;
807             }
808           }
809           set_bci(cmp->state_before()->bci());
810           set_canonical(canon);
811         }
812       }
813     }
814   } else if (rt == objectNull &&
815            (l->as_NewInstance() || l->as_NewArray() ||
816              (l->as_Local() && l->as_Local()->is_receiver()))) {
817     if (x->cond() == Instruction::eql) {
818       BlockBegin* sux = x->fsux();
819       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
820     } else {
821       assert(x->cond() == Instruction::neq, "only other valid case");
822       BlockBegin* sux = x->tsux();
823       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
824     }
825   }
826 }
827 
828 
829 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
830   if (x->tag()->type()->is_constant()) {
831     int v = x->tag()->type()->as_IntConstant()->value();
832     BlockBegin* sux = x->default_sux();
833     if (v >= x->lo_key() && v <= x->hi_key()) {
834       sux = x->sux_at(v - x->lo_key());
835     }

846       if (v == x->key_at(i)) {
847         sux = x->sux_at(i);
848       }
849     }
850     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
851   }
852 }
853 
854 
855 void Canonicalizer::do_Return         (Return*          x) {}
856 void Canonicalizer::do_Throw          (Throw*           x) {}
857 void Canonicalizer::do_Base           (Base*            x) {}
858 void Canonicalizer::do_OsrEntry       (OsrEntry*        x) {}
859 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
860 void Canonicalizer::do_RoundFP        (RoundFP*         x) {}
861 void Canonicalizer::do_UnsafeGet      (UnsafeGet*       x) {}
862 void Canonicalizer::do_UnsafePut      (UnsafePut*       x) {}
863 void Canonicalizer::do_UnsafeGetAndSet(UnsafeGetAndSet* x) {}
864 void Canonicalizer::do_ProfileCall    (ProfileCall*     x) {}
865 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
866 void Canonicalizer::do_ProfileInvoke  (ProfileInvoke*   x) {}
867 void Canonicalizer::do_RuntimeCall    (RuntimeCall*     x) {}

868 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
869 #ifdef ASSERT
870 void Canonicalizer::do_Assert         (Assert*          x) {}
871 #endif
872 void Canonicalizer::do_MemBar         (MemBar*          x) {}

264     ciField* field = lf->field();
265     if (field->is_static_constant()) {
266       // Constant field loads are usually folded during parsing.
267       // But it doesn't happen with PatchALot, ScavengeRootsInCode < 2, or when
268       // holder class is being initialized during parsing (for static fields).
269       ciObject* c = field->constant_value().as_object();
270       if (!c->is_null_object()) {
271         set_constant(c->as_array()->length());
272       }
273     }
274   }
275 }
276 
277 void Canonicalizer::do_LoadIndexed    (LoadIndexed*     x) {
278   StableArrayConstant* array = x->array()->type()->as_StableArrayConstant();
279   IntConstant* index = x->index()->type()->as_IntConstant();
280 
281   assert(array == NULL || FoldStableValues, "not enabled");
282 
283   // Constant fold loads from stable arrays.
284   if (!x->should_profile() && !x->mismatched() && array != NULL && index != NULL) {
285     jint idx = index->value();
286     if (idx < 0 || idx >= array->value()->length()) {
287       // Leave the load as is. The range check will handle it.
288       return;
289     }
290 
291     ciConstant field_val = array->value()->element_value(idx);
292     if (!field_val.is_null_or_zero()) {
293       jint dimension = array->dimension();
294       assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info");
295       ValueType* value = NULL;
296       if (dimension > 1) {
297         // Preserve information about the dimension for the element.
298         assert(field_val.as_object()->is_array(), "not an array");
299         value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1);
300       } else {
301         assert(dimension == 1, "sanity");
302         value = as_ValueType(field_val);
303       }
304       set_canonical(new Constant(value));

623     if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
624       jint safebits = 0;
625       jint mask = op2->y()->type()->as_IntConstant()->value();
626       switch (x->op()) {
627         case Bytecodes::_i2b: safebits = 0x7f;   break;
628         case Bytecodes::_i2s: safebits = 0x7fff; break;
629         case Bytecodes::_i2c: safebits = 0xffff; break;
630         default             :                    break;
631       }
632       // When casting a masked integer to a smaller signed type, if
633       // the mask doesn't include the sign bit the cast isn't needed.
634       if (safebits && (mask & ~safebits) == 0) {
635         set_canonical(x->value());
636       }
637     }
638   }
639 
640 }
641 
642 void Canonicalizer::do_NullCheck      (NullCheck*       x) {
643   if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL || x->obj()->as_NewInlineTypeInstance()) {
644     set_canonical(x->obj());
645   } else {
646     Constant* con = x->obj()->as_Constant();
647     if (con) {
648       ObjectType* c = con->type()->as_ObjectType();
649       if (c && c->is_loaded()) {
650         ObjectConstant* oc = c->as_ObjectConstant();
651         if (!oc || !oc->value()->is_null_object()) {
652           set_canonical(con);
653         }
654       }
655     }
656   }
657 }
658 
659 void Canonicalizer::do_TypeCast       (TypeCast*        x) {}
660 void Canonicalizer::do_Invoke         (Invoke*          x) {}
661 void Canonicalizer::do_NewInstance    (NewInstance*     x) {}
662 void Canonicalizer::do_NewInlineTypeInstance(NewInlineTypeInstance* x) {}
663 void Canonicalizer::do_NewTypeArray   (NewTypeArray*    x) {}
664 void Canonicalizer::do_NewObjectArray (NewObjectArray*  x) {}
665 void Canonicalizer::do_NewMultiArray  (NewMultiArray*   x) {}
666 void Canonicalizer::do_Deoptimize     (Deoptimize*      x) {}
667 void Canonicalizer::do_CheckCast      (CheckCast*       x) {
668   if (x->klass()->is_loaded()) {
669     Value obj = x->obj();
670     ciType* klass = obj->exact_type();
671     if (klass == NULL) {
672       klass = obj->declared_type();
673     }
674     if (klass != NULL && klass->is_loaded()) {
675       bool is_interface = klass->is_instance_klass() &&
676                           klass->as_instance_klass()->is_interface();
677       // Interface casts can't be statically optimized away since verifier doesn't
678       // enforce interface types in bytecode.
679       if (!is_interface && klass->is_subtype_of(x->klass()) && (!x->is_null_free() || obj->is_null_free())) {
680         assert(!x->klass()->is_inlinetype() || x->klass() == klass, "Inline klasses can't have subtypes");
681         set_canonical(obj);
682         return;
683       }
684     }
685     // checkcast of null returns null for non null-free klasses
686     if (!x->is_null_free() && obj->is_null_obj()) {
687       set_canonical(obj);
688     }
689   }
690 }
691 void Canonicalizer::do_InstanceOf     (InstanceOf*      x) {
692   if (x->klass()->is_loaded()) {
693     Value obj = x->obj();
694     ciType* exact = obj->exact_type();
695     if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray() || obj->as_NewInlineTypeInstance())) {
696       set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
697       return;
698     }
699     // instanceof null returns false
700     if (obj->as_Constant() && obj->is_null_obj()) {
701       set_constant(0);
702     }
703   }
704 
705 }
706 void Canonicalizer::do_MonitorEnter   (MonitorEnter*    x) {}
707 void Canonicalizer::do_MonitorExit    (MonitorExit*     x) {}
708 void Canonicalizer::do_BlockBegin     (BlockBegin*      x) {}
709 void Canonicalizer::do_Goto           (Goto*            x) {}
710 
711 
712 static bool is_true(jlong x, If::Condition cond, jlong y) {
713   switch (cond) {
714     case If::eql: return x == y;
715     case If::neq: return x != y;
716     case If::lss: return x <  y;
717     case If::leq: return x <= y;
718     case If::gtr: return x >  y;
719     case If::geq: return x >= y;
720     default:

798           do_If(canon);
799         } else {
800           if (compilation()->profile_branches() || compilation()->is_profiling()) {
801             // TODO: If profiling, leave floating point comparisons unoptimized.
802             // We currently do not support profiling of the unordered case.
803             switch(cmp->op()) {
804               case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
805               case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
806                 set_canonical(x);
807                 return;
808               default:
809                 break;
810             }
811           }
812           set_bci(cmp->state_before()->bci());
813           set_canonical(canon);
814         }
815       }
816     }
817   } else if (rt == objectNull &&
818            (l->as_NewInstance() || l->as_NewArray() || l->as_NewInlineTypeInstance() ||
819              (l->as_Local() && l->as_Local()->is_receiver()))) {
820     if (x->cond() == Instruction::eql) {
821       BlockBegin* sux = x->fsux();
822       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
823     } else {
824       assert(x->cond() == Instruction::neq, "only other valid case");
825       BlockBegin* sux = x->tsux();
826       set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
827     }
828   }
829 }
830 
831 
832 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
833   if (x->tag()->type()->is_constant()) {
834     int v = x->tag()->type()->as_IntConstant()->value();
835     BlockBegin* sux = x->default_sux();
836     if (v >= x->lo_key() && v <= x->hi_key()) {
837       sux = x->sux_at(v - x->lo_key());
838     }

849       if (v == x->key_at(i)) {
850         sux = x->sux_at(i);
851       }
852     }
853     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
854   }
855 }
856 
857 
858 void Canonicalizer::do_Return         (Return*          x) {}
859 void Canonicalizer::do_Throw          (Throw*           x) {}
860 void Canonicalizer::do_Base           (Base*            x) {}
861 void Canonicalizer::do_OsrEntry       (OsrEntry*        x) {}
862 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
863 void Canonicalizer::do_RoundFP        (RoundFP*         x) {}
864 void Canonicalizer::do_UnsafeGet      (UnsafeGet*       x) {}
865 void Canonicalizer::do_UnsafePut      (UnsafePut*       x) {}
866 void Canonicalizer::do_UnsafeGetAndSet(UnsafeGetAndSet* x) {}
867 void Canonicalizer::do_ProfileCall    (ProfileCall*     x) {}
868 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
869 void Canonicalizer::do_ProfileInvoke    (ProfileInvoke* x) {}
870 void Canonicalizer::do_ProfileACmpTypes (ProfileACmpTypes* x) {}
871 void Canonicalizer::do_RuntimeCall      (RuntimeCall* x) {}
872 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
873 #ifdef ASSERT
874 void Canonicalizer::do_Assert         (Assert*          x) {}
875 #endif
876 void Canonicalizer::do_MemBar         (MemBar*          x) {}
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