1 /* 2 * Copyright (c) 2020, 2025, 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 "opto/addnode.hpp" 26 #include "opto/callnode.hpp" 27 #include "opto/connode.hpp" 28 #include "opto/convertnode.hpp" 29 #include "opto/phaseX.hpp" 30 #include "opto/rootnode.hpp" 31 #include "opto/subnode.hpp" 32 #include "opto/subtypenode.hpp" 33 34 const Type* SubTypeCheckNode::sub(const Type* sub_t, const Type* super_t) const { 35 const TypeKlassPtr* superk = super_t->isa_klassptr(); 36 assert(sub_t != Type::TOP && !TypePtr::NULL_PTR->higher_equal(sub_t), "should be not null"); 37 const TypeKlassPtr* subk = sub_t->isa_klassptr() ? sub_t->is_klassptr() : sub_t->is_oopptr()->as_klass_type(); 38 39 // Oop can't be a subtype of abstract type that has no subclass. 40 if (sub_t->isa_oopptr() && superk->isa_instklassptr() && superk->klass_is_exact()) { 41 ciKlass* superklass = superk->exact_klass(); 42 if (!superklass->is_interface() && superklass->is_abstract() && 43 !superklass->as_instance_klass()->has_subklass()) { 44 Compile::current()->dependencies()->assert_leaf_type(superklass); 45 return TypeInt::CC_GT; 46 } 47 } 48 49 if (subk != nullptr) { 50 switch (Compile::current()->static_subtype_check(superk, subk, false)) { 51 case Compile::SSC_always_false: 52 return TypeInt::CC_GT; 53 case Compile::SSC_always_true: 54 return TypeInt::CC_EQ; 55 case Compile::SSC_easy_test: 56 case Compile::SSC_full_test: 57 break; 58 default: 59 ShouldNotReachHere(); 60 } 61 } 62 63 return bottom_type(); 64 } 65 66 Node *SubTypeCheckNode::Ideal(PhaseGVN* phase, bool can_reshape) { 67 Node* obj_or_subklass = in(ObjOrSubKlass); 68 Node* superklass = in(SuperKlass); 69 70 if (obj_or_subklass == nullptr || 71 superklass == nullptr) { 72 return nullptr; 73 } 74 75 const Type* sub_t = phase->type(obj_or_subklass); 76 const Type* super_t = phase->type(superklass); 77 78 if (!super_t->isa_klassptr() || 79 (!sub_t->isa_klassptr() && !sub_t->isa_oopptr())) { 80 return nullptr; 81 } 82 83 Node* addr = nullptr; 84 if (obj_or_subklass->is_DecodeNKlass()) { 85 if (obj_or_subklass->in(1) != nullptr && 86 obj_or_subklass->in(1)->Opcode() == Op_LoadNKlass) { 87 addr = obj_or_subklass->in(1)->in(MemNode::Address); 88 } 89 } else if (obj_or_subklass->Opcode() == Op_LoadKlass) { 90 addr = obj_or_subklass->in(MemNode::Address); 91 } 92 93 if (addr != nullptr) { 94 intptr_t con = 0; 95 Node* obj = AddPNode::Ideal_base_and_offset(addr, phase, con); 96 if (con == Type::klass_offset() && obj != nullptr) { 97 assert(is_oop(phase, obj), "only for oop input"); 98 set_req_X(ObjOrSubKlass, obj, phase); 99 return this; 100 } 101 } 102 103 // AllocateNode might have more accurate klass input 104 Node* allocated_klass = AllocateNode::Ideal_klass(obj_or_subklass, phase); 105 if (allocated_klass != nullptr) { 106 assert(is_oop(phase, obj_or_subklass), "only for oop input"); 107 set_req_X(ObjOrSubKlass, allocated_klass, phase); 108 return this; 109 } 110 111 // Verify that optimizing the subtype check to a simple code pattern 112 // when possible would not constant fold better 113 assert(verify(phase), "missing Value() optimization"); 114 115 return nullptr; 116 } 117 118 #ifdef ASSERT 119 bool SubTypeCheckNode::is_oop(PhaseGVN* phase, Node* n) { 120 const Type* t = phase->type(n); 121 if (!t->isa_oopptr() && t != Type::TOP) { 122 n->dump(); 123 t->dump(); tty->cr(); 124 return false; 125 } 126 return true; 127 } 128 129 static Node* record_for_cleanup(Node* n, PhaseGVN* phase) { 130 if (phase->is_IterGVN()) { 131 phase->is_IterGVN()->_worklist.push(n); // record for cleanup 132 } 133 return n; 134 } 135 bool SubTypeCheckNode::verify_helper(PhaseGVN* phase, Node* subklass, const Type* cached_t) { 136 Node* cmp = phase->transform(new CmpPNode(subklass, in(SuperKlass))); 137 record_for_cleanup(cmp, phase); 138 139 const Type* cmp_t = phase->type(cmp); 140 const Type* t = Value(phase); 141 142 if (t == cmp_t || 143 t != cached_t || // previous observations don't hold anymore 144 (cmp_t != TypeInt::CC_GT && cmp_t != TypeInt::CC_EQ)) { 145 return true; 146 } else { 147 t->dump(); tty->cr(); 148 this->dump(2); tty->cr(); 149 cmp_t->dump(); tty->cr(); 150 subklass->dump(2); tty->cr(); 151 tty->print_cr("=============================="); 152 phase->C->root()->dump(9999); 153 return false; 154 } 155 } 156 157 // Verify that optimizing the subtype check to a simple code pattern when possible would not constant fold better. 158 bool SubTypeCheckNode::verify(PhaseGVN* phase) { 159 Compile* C = phase->C; 160 Node* obj_or_subklass = in(ObjOrSubKlass); 161 Node* superklass = in(SuperKlass); 162 163 const Type* sub_t = phase->type(obj_or_subklass); 164 const Type* super_t = phase->type(superklass); 165 166 const TypeKlassPtr* superk = super_t->isa_klassptr(); 167 const TypeKlassPtr* subk = sub_t->isa_klassptr() ? sub_t->is_klassptr() : sub_t->is_oopptr()->as_klass_type(); 168 169 if (super_t->singleton() && subk != nullptr) { 170 if (obj_or_subklass->bottom_type() == Type::TOP) { 171 // The bottom type of obj_or_subklass is TOP, despite its recorded type 172 // being an OOP or a klass pointer. This can happen for example in 173 // transient scenarios where obj_or_subklass is a projection of the TOP 174 // node. In such cases, skip verification to avoid violating the contract 175 // of LoadKlassNode::make(). This does not weaken the effect of verify(), 176 // as SubTypeCheck nodes with TOP obj_or_subklass inputs are dead anyway. 177 return true; 178 } 179 const Type* cached_t = Value(phase); // cache the type to validate consistency 180 switch (C->static_subtype_check(superk, subk)) { 181 case Compile::SSC_easy_test: { 182 return verify_helper(phase, load_klass(phase), cached_t); 183 } 184 case Compile::SSC_full_test: { 185 Node* p1 = phase->transform(new AddPNode(superklass, superklass, phase->MakeConX(in_bytes(Klass::super_check_offset_offset())))); 186 Node* chk_off = phase->transform(new LoadINode(nullptr, C->immutable_memory(), p1, phase->type(p1)->is_ptr(), TypeInt::INT, MemNode::unordered)); 187 record_for_cleanup(chk_off, phase); 188 189 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset()); 190 bool might_be_cache = (phase->find_int_con(chk_off, cacheoff_con) == cacheoff_con); 191 if (!might_be_cache) { 192 Node* subklass = load_klass(phase); 193 Node* chk_off_X = chk_off; 194 #ifdef _LP64 195 chk_off_X = phase->transform(new ConvI2LNode(chk_off_X)); 196 #endif 197 Node* p2 = phase->transform(new AddPNode(subklass, subklass, chk_off_X)); 198 Node* nkls = phase->transform(LoadKlassNode::make(*phase, nullptr, C->immutable_memory(), p2, phase->type(p2)->is_ptr(), TypeInstKlassPtr::OBJECT_OR_NULL)); 199 200 return verify_helper(phase, nkls, cached_t); 201 } 202 break; 203 } 204 case Compile::SSC_always_false: 205 case Compile::SSC_always_true: 206 default: { 207 break; // nothing to do 208 } 209 } 210 } 211 212 return true; 213 } 214 215 Node* SubTypeCheckNode::load_klass(PhaseGVN* phase) const { 216 Node* obj_or_subklass = in(ObjOrSubKlass); 217 const Type* sub_t = phase->type(obj_or_subklass); 218 Node* subklass = nullptr; 219 if (sub_t->isa_oopptr()) { 220 Node* adr = phase->transform(new AddPNode(obj_or_subklass, obj_or_subklass, phase->MakeConX(Type::klass_offset()))); 221 subklass = phase->transform(LoadKlassNode::make(*phase, nullptr, phase->C->immutable_memory(), adr, TypeInstPtr::KLASS)); 222 record_for_cleanup(subklass, phase); 223 } else { 224 subklass = obj_or_subklass; 225 } 226 return subklass; 227 } 228 #endif 229 230 uint SubTypeCheckNode::size_of() const { 231 return sizeof(*this); 232 } 233 234 uint SubTypeCheckNode::hash() const { 235 return NO_HASH; 236 } 237 238 #ifndef PRODUCT 239 void SubTypeCheckNode::dump_spec(outputStream* st) const { 240 if (_method != nullptr) { 241 st->print(" profiled at:"); 242 _method->print_short_name(st); 243 st->print(":%d", _bci); 244 } 245 } 246 #endif