1 /*
2 * Copyright (c) 2020, 2023, 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 "opto/addnode.hpp"
27 #include "opto/callnode.hpp"
28 #include "opto/connode.hpp"
29 #include "opto/convertnode.hpp"
30 #include "opto/phaseX.hpp"
31 #include "opto/rootnode.hpp"
32 #include "opto/subnode.hpp"
33 #include "opto/subtypenode.hpp"
34
35 const Type* SubTypeCheckNode::sub(const Type* sub_t, const Type* super_t) const {
36 const TypeKlassPtr* superk = super_t->isa_klassptr();
37 assert(sub_t != Type::TOP && !TypePtr::NULL_PTR->higher_equal(sub_t), "should be not null");
38 const TypeKlassPtr* subk = sub_t->isa_klassptr() ? sub_t->is_klassptr() : sub_t->is_oopptr()->as_klass_type();
39
40 // Oop can't be a subtype of abstract type that has no subclass.
41 if (sub_t->isa_oopptr() && superk->isa_instklassptr() && superk->klass_is_exact()) {
42 ciKlass* superklass = superk->exact_klass();
43 if (!superklass->is_interface() && superklass->is_abstract() &&
44 !superklass->as_instance_klass()->has_subklass()) {
45 Compile::current()->dependencies()->assert_leaf_type(superklass);
46 return TypeInt::CC_GT;
47 }
48 }
49
50 // FIXME: shouldn't this be encoded in helper methods of the type system (maybe_java_subtype_of() etc.?)
51 // Similar to logic in CmpPNode::sub()
52 bool unrelated_classes = false;
53 // Handle inline type arrays
54 if (subk->flat_in_array() && superk->not_flat_in_array()) {
55 // The subtype is in flat arrays and the supertype is not in flat arrays. Must be unrelated.
56 unrelated_classes = true;
57 } else if (subk->is_not_flat() && superk->is_flat()) {
58 // The subtype is a non-flat array and the supertype is a flat array. Must be unrelated.
59 unrelated_classes = true;
60 } else if (subk->is_not_null_free() && superk->is_null_free()) {
61 // The subtype is a nullable array and the supertype is null-free array. Must be unrelated.
62 unrelated_classes = true;
63 }
64 if (unrelated_classes) {
65 TypePtr::PTR jp = sub_t->is_ptr()->join_ptr(super_t->is_ptr()->_ptr);
66 if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
67 return TypeInt::CC_GT;
68 }
69 }
70
71 if (subk != nullptr) {
72 switch (Compile::current()->static_subtype_check(superk, subk, false)) {
73 case Compile::SSC_always_false:
74 return TypeInt::CC_GT;
75 case Compile::SSC_always_true:
76 return TypeInt::CC_EQ;
77 case Compile::SSC_easy_test:
78 case Compile::SSC_full_test:
79 break;
80 default:
81 ShouldNotReachHere();
82 }
83 }
84
85 return bottom_type();
86 }
87
88 Node *SubTypeCheckNode::Ideal(PhaseGVN* phase, bool can_reshape) {
89 Node* obj_or_subklass = in(ObjOrSubKlass);
90 Node* superklass = in(SuperKlass);
91
92 if (obj_or_subklass == nullptr ||
93 superklass == nullptr) {
94 return nullptr;
95 }
96
97 const Type* sub_t = phase->type(obj_or_subklass);
98 const Type* super_t = phase->type(superklass);
99
100 if (!super_t->isa_klassptr() ||
101 (!sub_t->isa_klassptr() && !sub_t->isa_oopptr())) {
102 return nullptr;
103 }
104
105 Node* addr = nullptr;
106 if (obj_or_subklass->is_DecodeNKlass()) {
107 if (obj_or_subklass->in(1) != nullptr &&
108 obj_or_subklass->in(1)->Opcode() == Op_LoadNKlass) {
109 addr = obj_or_subklass->in(1)->in(MemNode::Address);
110 }
111 } else if (obj_or_subklass->Opcode() == Op_LoadKlass) {
112 addr = obj_or_subklass->in(MemNode::Address);
113 }
114
115 if (addr != nullptr) {
116 intptr_t con = 0;
117 Node* obj = AddPNode::Ideal_base_and_offset(addr, phase, con);
118 if (con == oopDesc::klass_offset_in_bytes() && obj != nullptr) {
119 assert(is_oop(phase, obj), "only for oop input");
120 set_req_X(ObjOrSubKlass, obj, phase);
121 return this;
122 }
123 }
124
125 // AllocateNode might have more accurate klass input
126 Node* allocated_klass = AllocateNode::Ideal_klass(obj_or_subklass, phase);
127 if (allocated_klass != nullptr) {
128 assert(is_oop(phase, obj_or_subklass), "only for oop input");
129 set_req_X(ObjOrSubKlass, allocated_klass, phase);
130 return this;
131 }
132
133 // Verify that optimizing the subtype check to a simple code pattern
134 // when possible would not constant fold better
135 // TODO 8325106
136 // assert(verify(phase), "missing Value() optimization");
137
138 return nullptr;
139 }
140
141 #ifdef ASSERT
142 bool SubTypeCheckNode::is_oop(PhaseGVN* phase, Node* n) {
143 const Type* t = phase->type(n);
144 if (!t->isa_oopptr() && t != Type::TOP) {
145 n->dump();
146 t->dump(); tty->cr();
147 return false;
148 }
149 return true;
150 }
151
152 static Node* record_for_cleanup(Node* n, PhaseGVN* phase) {
153 if (phase->is_IterGVN()) {
154 phase->is_IterGVN()->_worklist.push(n); // record for cleanup
155 }
156 return n;
157 }
158 bool SubTypeCheckNode::verify_helper(PhaseGVN* phase, Node* subklass, const Type* cached_t) {
159 Node* cmp = phase->transform(new CmpPNode(subklass, in(SuperKlass)));
160 record_for_cleanup(cmp, phase);
161
162 const Type* cmp_t = phase->type(cmp);
163 const Type* t = Value(phase);
164
165 if (t == cmp_t ||
166 t != cached_t || // previous observations don't hold anymore
167 (cmp_t != TypeInt::CC_GT && cmp_t != TypeInt::CC_EQ)) {
168 return true;
169 } else {
170 t->dump(); tty->cr();
171 this->dump(2); tty->cr();
172 cmp_t->dump(); tty->cr();
173 subklass->dump(2); tty->cr();
174 tty->print_cr("==============================");
175 phase->C->root()->dump(9999);
176 return false;
177 }
178 }
179
180 // Verify that optimizing the subtype check to a simple code pattern when possible would not constant fold better.
181 bool SubTypeCheckNode::verify(PhaseGVN* phase) {
182 Compile* C = phase->C;
183 Node* obj_or_subklass = in(ObjOrSubKlass);
184 Node* superklass = in(SuperKlass);
185
186 const Type* sub_t = phase->type(obj_or_subklass);
187 const Type* super_t = phase->type(superklass);
188
189 const TypeKlassPtr* superk = super_t->isa_klassptr();
190 const TypeKlassPtr* subk = sub_t->isa_klassptr() ? sub_t->is_klassptr() : sub_t->is_oopptr()->as_klass_type();
191
192 if (super_t->singleton() && subk != nullptr) {
193 if (obj_or_subklass->bottom_type() == Type::TOP) {
194 // The bottom type of obj_or_subklass is TOP, despite its recorded type
195 // being an OOP or a klass pointer. This can happen for example in
196 // transient scenarios where obj_or_subklass is a projection of the TOP
197 // node. In such cases, skip verification to avoid violating the contract
198 // of LoadKlassNode::make(). This does not weaken the effect of verify(),
199 // as SubTypeCheck nodes with TOP obj_or_subklass inputs are dead anyway.
200 return true;
201 }
202 const Type* cached_t = Value(phase); // cache the type to validate consistency
203 switch (C->static_subtype_check(superk, subk)) {
204 case Compile::SSC_easy_test: {
205 return verify_helper(phase, load_klass(phase), cached_t);
206 }
207 case Compile::SSC_full_test: {
208 Node* p1 = phase->transform(new AddPNode(superklass, superklass, phase->MakeConX(in_bytes(Klass::super_check_offset_offset()))));
209 Node* chk_off = phase->transform(new LoadINode(nullptr, C->immutable_memory(), p1, phase->type(p1)->is_ptr(), TypeInt::INT, MemNode::unordered));
210 record_for_cleanup(chk_off, phase);
211
212 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset());
213 bool might_be_cache = (phase->find_int_con(chk_off, cacheoff_con) == cacheoff_con);
214 if (!might_be_cache) {
215 Node* subklass = load_klass(phase);
216 Node* chk_off_X = chk_off;
217 #ifdef _LP64
218 chk_off_X = phase->transform(new ConvI2LNode(chk_off_X));
219 #endif
220 Node* p2 = phase->transform(new AddPNode(subklass, subklass, chk_off_X));
221 Node* nkls = phase->transform(LoadKlassNode::make(*phase, nullptr, C->immutable_memory(), p2, phase->type(p2)->is_ptr(), TypeInstKlassPtr::OBJECT_OR_NULL));
222
223 return verify_helper(phase, nkls, cached_t);
224 }
225 break;
226 }
227 case Compile::SSC_always_false:
228 case Compile::SSC_always_true:
229 default: {
230 break; // nothing to do
231 }
232 }
233 }
234
235 return true;
236 }
237
238 Node* SubTypeCheckNode::load_klass(PhaseGVN* phase) const {
239 Node* obj_or_subklass = in(ObjOrSubKlass);
240 const Type* sub_t = phase->type(obj_or_subklass);
241 Node* subklass = nullptr;
242 if (sub_t->isa_oopptr()) {
243 Node* adr = phase->transform(new AddPNode(obj_or_subklass, obj_or_subklass, phase->MakeConX(oopDesc::klass_offset_in_bytes())));
244 subklass = phase->transform(LoadKlassNode::make(*phase, nullptr, phase->C->immutable_memory(), adr, TypeInstPtr::KLASS));
245 record_for_cleanup(subklass, phase);
246 } else {
247 subklass = obj_or_subklass;
248 }
249 return subklass;
250 }
251 #endif
252
253 uint SubTypeCheckNode::size_of() const {
254 return sizeof(*this);
255 }
256
257 uint SubTypeCheckNode::hash() const {
258 return NO_HASH;
259 }
260
261 #ifndef PRODUCT
262 void SubTypeCheckNode::dump_spec(outputStream* st) const {
263 if (_method != nullptr) {
264 st->print(" profiled at: ");
265 _method->print_short_name(st);
266 st->print(":%d", _bci);
267 }
268 }
269 #endif