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src/hotspot/share/opto/memnode.cpp

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 247       assert(phase->C->get_alias_index(t) == phase->C->get_alias_index(t_adr), "correct memory chain");
 248     }
 249   }
 250   return result;
 251 }
 252 
 253 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem,  const TypePtr *tp, const TypePtr *adr_check, outputStream *st) {
 254   uint alias_idx = phase->C->get_alias_index(tp);
 255   Node *mem = mmem;
 256 #ifdef ASSERT
 257   {
 258     // Check that current type is consistent with the alias index used during graph construction
 259     assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx");
 260     bool consistent =  adr_check == nullptr || adr_check->empty() ||
 261                        phase->C->must_alias(adr_check, alias_idx );
 262     // Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
 263     if( !consistent && adr_check != nullptr && !adr_check->empty() &&
 264                tp->isa_aryptr() &&        tp->offset() == Type::OffsetBot &&
 265         adr_check->isa_aryptr() && adr_check->offset() != Type::OffsetBot &&
 266         ( adr_check->offset() == arrayOopDesc::length_offset_in_bytes() ||
 267           adr_check->offset() == oopDesc::klass_offset_in_bytes() ||
 268           adr_check->offset() == oopDesc::mark_offset_in_bytes() ) ) {
 269       // don't assert if it is dead code.
 270       consistent = true;
 271     }
 272     if( !consistent ) {
 273       st->print("alias_idx==%d, adr_check==", alias_idx);
 274       if( adr_check == nullptr ) {
 275         st->print("null");
 276       } else {
 277         adr_check->dump();
 278       }
 279       st->cr();
 280       print_alias_types();
 281       assert(consistent, "adr_check must match alias idx");
 282     }
 283   }
 284 #endif
 285   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
 286   // means an array I have not precisely typed yet.  Do not do any
 287   // alias stuff with it any time soon.

1001     for (size_t i = 0; i < sizeof offsets / sizeof offsets[0]; i++) {
1002       if (offset == offsets[i]) {
1003         return true;
1004       }
1005     }
1006   }
1007 
1008   return false;
1009 }
1010 #endif
1011 
1012 //----------------------------LoadNode::make-----------------------------------
1013 // Polymorphic factory method:
1014 Node* LoadNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt, BasicType bt, MemOrd mo,
1015                      ControlDependency control_dependency, bool require_atomic_access, bool unaligned, bool mismatched, bool unsafe, uint8_t barrier_data) {
1016   Compile* C = gvn.C;
1017   assert(adr->is_top() || C->get_alias_index(gvn.type(adr)->is_ptr()) == C->get_alias_index(adr_type), "adr and adr_type must agree");
1018 
1019   // sanity check the alias category against the created node type
1020   assert(!(adr_type->isa_oopptr() &&
1021            adr_type->offset() == oopDesc::klass_offset_in_bytes()),
1022          "use LoadKlassNode instead");
1023   assert(!(adr_type->isa_aryptr() &&
1024            adr_type->offset() == arrayOopDesc::length_offset_in_bytes()),
1025          "use LoadRangeNode instead");
1026   // Check control edge of raw loads
1027   assert( ctl != nullptr || C->get_alias_index(adr_type) != Compile::AliasIdxRaw ||
1028           // oop will be recorded in oop map if load crosses safepoint
1029           rt->isa_oopptr() || is_immutable_value(adr),
1030           "raw memory operations should have control edge");
1031   LoadNode* load = nullptr;
1032   switch (bt) {
1033   case T_BOOLEAN: load = new LoadUBNode(ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1034   case T_BYTE:    load = new LoadBNode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1035   case T_INT:     load = new LoadINode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1036   case T_CHAR:    load = new LoadUSNode(ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1037   case T_SHORT:   load = new LoadSNode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1038   case T_LONG:    load = new LoadLNode (ctl, mem, adr, adr_type, rt->is_long(), mo, control_dependency, require_atomic_access); break;
1039   case T_FLOAT:   load = new LoadFNode (ctl, mem, adr, adr_type, rt,            mo, control_dependency); break;
1040   case T_DOUBLE:  load = new LoadDNode (ctl, mem, adr, adr_type, rt,            mo, control_dependency, require_atomic_access); break;
1041   case T_ADDRESS: load = new LoadPNode (ctl, mem, adr, adr_type, rt->is_ptr(),  mo, control_dependency); break;

2560         // constant oop => constant klass
2561         if (offset == java_lang_Class::array_klass_offset()) {
2562           if (t->is_void()) {
2563             // We cannot create a void array.  Since void is a primitive type return null
2564             // klass.  Users of this result need to do a null check on the returned klass.
2565             return TypePtr::NULL_PTR;
2566           }
2567           return TypeKlassPtr::make(ciArrayKlass::make(t), Type::trust_interfaces);
2568         }
2569         if (!t->is_klass()) {
2570           // a primitive Class (e.g., int.class) has null for a klass field
2571           return TypePtr::NULL_PTR;
2572         }
2573         // Fold up the load of the hidden field
2574         return TypeKlassPtr::make(t->as_klass(), Type::trust_interfaces);
2575       }
2576       // non-constant mirror, so we can't tell what's going on
2577     }
2578     if (!tinst->is_loaded())
2579       return _type;             // Bail out if not loaded
2580     if (offset == oopDesc::klass_offset_in_bytes()) {
2581       return tinst->as_klass_type(true);
2582     }
2583   }
2584 
2585   // Check for loading klass from an array
2586   const TypeAryPtr *tary = tp->isa_aryptr();
2587   if (tary != nullptr &&
2588       tary->offset() == oopDesc::klass_offset_in_bytes()) {
2589     return tary->as_klass_type(true);
2590   }
2591 
2592   // Check for loading klass from an array klass
2593   const TypeKlassPtr *tkls = tp->isa_klassptr();
2594   if (tkls != nullptr && !StressReflectiveCode) {
2595     if (!tkls->is_loaded())
2596      return _type;             // Bail out if not loaded
2597     if (tkls->isa_aryklassptr() && tkls->is_aryklassptr()->elem()->isa_klassptr() &&
2598         tkls->offset() == in_bytes(ObjArrayKlass::element_klass_offset())) {
2599       // // Always returning precise element type is incorrect,
2600       // // e.g., element type could be object and array may contain strings
2601       // return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
2602 
2603       // The array's TypeKlassPtr was declared 'precise' or 'not precise'
2604       // according to the element type's subclassing.
2605       return tkls->is_aryklassptr()->elem()->isa_klassptr()->cast_to_exactness(tkls->klass_is_exact());
2606     }
2607     if (tkls->isa_instklassptr() != nullptr && tkls->klass_is_exact() &&
2608         tkls->offset() == in_bytes(Klass::super_offset())) {

2634   Node* x = LoadNode::Identity(phase);
2635   if (x != this)  return x;
2636 
2637   // Take apart the address into an oop and offset.
2638   // Return 'this' if we cannot.
2639   Node*    adr    = in(MemNode::Address);
2640   intptr_t offset = 0;
2641   Node*    base   = AddPNode::Ideal_base_and_offset(adr, phase, offset);
2642   if (base == nullptr)     return this;
2643   const TypeOopPtr* toop = phase->type(adr)->isa_oopptr();
2644   if (toop == nullptr)     return this;
2645 
2646   // Step over potential GC barrier for OopHandle resolve
2647   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2648   if (bs->is_gc_barrier_node(base)) {
2649     base = bs->step_over_gc_barrier(base);
2650   }
2651 
2652   // We can fetch the klass directly through an AllocateNode.
2653   // This works even if the klass is not constant (clone or newArray).
2654   if (offset == oopDesc::klass_offset_in_bytes()) {
2655     Node* allocated_klass = AllocateNode::Ideal_klass(base, phase);
2656     if (allocated_klass != nullptr) {
2657       return allocated_klass;
2658     }
2659   }
2660 
2661   // Simplify k.java_mirror.as_klass to plain k, where k is a Klass*.
2662   // See inline_native_Class_query for occurrences of these patterns.
2663   // Java Example:  x.getClass().isAssignableFrom(y)
2664   //
2665   // This improves reflective code, often making the Class
2666   // mirror go completely dead.  (Current exception:  Class
2667   // mirrors may appear in debug info, but we could clean them out by
2668   // introducing a new debug info operator for Klass.java_mirror).
2669 
2670   if (toop->isa_instptr() && toop->is_instptr()->instance_klass() == phase->C->env()->Class_klass()
2671       && offset == java_lang_Class::klass_offset()) {
2672     if (base->is_Load()) {
2673       Node* base2 = base->in(MemNode::Address);
2674       if (base2->is_Load()) { /* direct load of a load which is the OopHandle */

 247       assert(phase->C->get_alias_index(t) == phase->C->get_alias_index(t_adr), "correct memory chain");
 248     }
 249   }
 250   return result;
 251 }
 252 
 253 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem,  const TypePtr *tp, const TypePtr *adr_check, outputStream *st) {
 254   uint alias_idx = phase->C->get_alias_index(tp);
 255   Node *mem = mmem;
 256 #ifdef ASSERT
 257   {
 258     // Check that current type is consistent with the alias index used during graph construction
 259     assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx");
 260     bool consistent =  adr_check == nullptr || adr_check->empty() ||
 261                        phase->C->must_alias(adr_check, alias_idx );
 262     // Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
 263     if( !consistent && adr_check != nullptr && !adr_check->empty() &&
 264                tp->isa_aryptr() &&        tp->offset() == Type::OffsetBot &&
 265         adr_check->isa_aryptr() && adr_check->offset() != Type::OffsetBot &&
 266         ( adr_check->offset() == arrayOopDesc::length_offset_in_bytes() ||
 267           adr_check->offset() == Type::klass_offset() ||
 268           adr_check->offset() == oopDesc::mark_offset_in_bytes() ) ) {
 269       // don't assert if it is dead code.
 270       consistent = true;
 271     }
 272     if( !consistent ) {
 273       st->print("alias_idx==%d, adr_check==", alias_idx);
 274       if( adr_check == nullptr ) {
 275         st->print("null");
 276       } else {
 277         adr_check->dump();
 278       }
 279       st->cr();
 280       print_alias_types();
 281       assert(consistent, "adr_check must match alias idx");
 282     }
 283   }
 284 #endif
 285   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
 286   // means an array I have not precisely typed yet.  Do not do any
 287   // alias stuff with it any time soon.

1001     for (size_t i = 0; i < sizeof offsets / sizeof offsets[0]; i++) {
1002       if (offset == offsets[i]) {
1003         return true;
1004       }
1005     }
1006   }
1007 
1008   return false;
1009 }
1010 #endif
1011 
1012 //----------------------------LoadNode::make-----------------------------------
1013 // Polymorphic factory method:
1014 Node* LoadNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt, BasicType bt, MemOrd mo,
1015                      ControlDependency control_dependency, bool require_atomic_access, bool unaligned, bool mismatched, bool unsafe, uint8_t barrier_data) {
1016   Compile* C = gvn.C;
1017   assert(adr->is_top() || C->get_alias_index(gvn.type(adr)->is_ptr()) == C->get_alias_index(adr_type), "adr and adr_type must agree");
1018 
1019   // sanity check the alias category against the created node type
1020   assert(!(adr_type->isa_oopptr() &&
1021            adr_type->offset() == Type::klass_offset()),
1022          "use LoadKlassNode instead");
1023   assert(!(adr_type->isa_aryptr() &&
1024            adr_type->offset() == arrayOopDesc::length_offset_in_bytes()),
1025          "use LoadRangeNode instead");
1026   // Check control edge of raw loads
1027   assert( ctl != nullptr || C->get_alias_index(adr_type) != Compile::AliasIdxRaw ||
1028           // oop will be recorded in oop map if load crosses safepoint
1029           rt->isa_oopptr() || is_immutable_value(adr),
1030           "raw memory operations should have control edge");
1031   LoadNode* load = nullptr;
1032   switch (bt) {
1033   case T_BOOLEAN: load = new LoadUBNode(ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1034   case T_BYTE:    load = new LoadBNode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1035   case T_INT:     load = new LoadINode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1036   case T_CHAR:    load = new LoadUSNode(ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1037   case T_SHORT:   load = new LoadSNode (ctl, mem, adr, adr_type, rt->is_int(),  mo, control_dependency); break;
1038   case T_LONG:    load = new LoadLNode (ctl, mem, adr, adr_type, rt->is_long(), mo, control_dependency, require_atomic_access); break;
1039   case T_FLOAT:   load = new LoadFNode (ctl, mem, adr, adr_type, rt,            mo, control_dependency); break;
1040   case T_DOUBLE:  load = new LoadDNode (ctl, mem, adr, adr_type, rt,            mo, control_dependency, require_atomic_access); break;
1041   case T_ADDRESS: load = new LoadPNode (ctl, mem, adr, adr_type, rt->is_ptr(),  mo, control_dependency); break;

2560         // constant oop => constant klass
2561         if (offset == java_lang_Class::array_klass_offset()) {
2562           if (t->is_void()) {
2563             // We cannot create a void array.  Since void is a primitive type return null
2564             // klass.  Users of this result need to do a null check on the returned klass.
2565             return TypePtr::NULL_PTR;
2566           }
2567           return TypeKlassPtr::make(ciArrayKlass::make(t), Type::trust_interfaces);
2568         }
2569         if (!t->is_klass()) {
2570           // a primitive Class (e.g., int.class) has null for a klass field
2571           return TypePtr::NULL_PTR;
2572         }
2573         // Fold up the load of the hidden field
2574         return TypeKlassPtr::make(t->as_klass(), Type::trust_interfaces);
2575       }
2576       // non-constant mirror, so we can't tell what's going on
2577     }
2578     if (!tinst->is_loaded())
2579       return _type;             // Bail out if not loaded
2580     if (offset == Type::klass_offset()) {
2581       return tinst->as_klass_type(true);
2582     }
2583   }
2584 
2585   // Check for loading klass from an array
2586   const TypeAryPtr *tary = tp->isa_aryptr();
2587   if (tary != nullptr &&
2588       tary->offset() == Type::klass_offset()) {
2589     return tary->as_klass_type(true);
2590   }
2591 
2592   // Check for loading klass from an array klass
2593   const TypeKlassPtr *tkls = tp->isa_klassptr();
2594   if (tkls != nullptr && !StressReflectiveCode) {
2595     if (!tkls->is_loaded())
2596      return _type;             // Bail out if not loaded
2597     if (tkls->isa_aryklassptr() && tkls->is_aryklassptr()->elem()->isa_klassptr() &&
2598         tkls->offset() == in_bytes(ObjArrayKlass::element_klass_offset())) {
2599       // // Always returning precise element type is incorrect,
2600       // // e.g., element type could be object and array may contain strings
2601       // return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
2602 
2603       // The array's TypeKlassPtr was declared 'precise' or 'not precise'
2604       // according to the element type's subclassing.
2605       return tkls->is_aryklassptr()->elem()->isa_klassptr()->cast_to_exactness(tkls->klass_is_exact());
2606     }
2607     if (tkls->isa_instklassptr() != nullptr && tkls->klass_is_exact() &&
2608         tkls->offset() == in_bytes(Klass::super_offset())) {

2634   Node* x = LoadNode::Identity(phase);
2635   if (x != this)  return x;
2636 
2637   // Take apart the address into an oop and offset.
2638   // Return 'this' if we cannot.
2639   Node*    adr    = in(MemNode::Address);
2640   intptr_t offset = 0;
2641   Node*    base   = AddPNode::Ideal_base_and_offset(adr, phase, offset);
2642   if (base == nullptr)     return this;
2643   const TypeOopPtr* toop = phase->type(adr)->isa_oopptr();
2644   if (toop == nullptr)     return this;
2645 
2646   // Step over potential GC barrier for OopHandle resolve
2647   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2648   if (bs->is_gc_barrier_node(base)) {
2649     base = bs->step_over_gc_barrier(base);
2650   }
2651 
2652   // We can fetch the klass directly through an AllocateNode.
2653   // This works even if the klass is not constant (clone or newArray).
2654   if (offset == Type::klass_offset()) {
2655     Node* allocated_klass = AllocateNode::Ideal_klass(base, phase);
2656     if (allocated_klass != nullptr) {
2657       return allocated_klass;
2658     }
2659   }
2660 
2661   // Simplify k.java_mirror.as_klass to plain k, where k is a Klass*.
2662   // See inline_native_Class_query for occurrences of these patterns.
2663   // Java Example:  x.getClass().isAssignableFrom(y)
2664   //
2665   // This improves reflective code, often making the Class
2666   // mirror go completely dead.  (Current exception:  Class
2667   // mirrors may appear in debug info, but we could clean them out by
2668   // introducing a new debug info operator for Klass.java_mirror).
2669 
2670   if (toop->isa_instptr() && toop->is_instptr()->instance_klass() == phase->C->env()->Class_klass()
2671       && offset == java_lang_Class::klass_offset()) {
2672     if (base->is_Load()) {
2673       Node* base2 = base->in(MemNode::Address);
2674       if (base2->is_Load()) { /* direct load of a load which is the OopHandle */
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