1 /*
2 * Copyright (c) 2018, 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_Defs.hpp"
27 #include "c1/c1_LIRGenerator.hpp"
28 #include "gc/shared/c1/barrierSetC1.hpp"
29 #include "utilities/macros.hpp"
30
31 #ifndef PATCHED_ADDR
32 #define PATCHED_ADDR (max_jint)
33 #endif
34
35 #ifdef ASSERT
36 #define __ gen->lir(__FILE__, __LINE__)->
37 #else
38 #define __ gen->lir()->
39 #endif
40
41 LIR_Opr BarrierSetC1::resolve_address(LIRAccess& access, bool resolve_in_register) {
42 DecoratorSet decorators = access.decorators();
43 bool is_array = (decorators & IS_ARRAY) != 0;
44 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
45
46 LIRItem& base = access.base().item();
47 LIR_Opr offset = access.offset().opr();
48 LIRGenerator *gen = access.gen();
49
50 LIR_Opr addr_opr;
51 if (is_array) {
52 addr_opr = LIR_OprFact::address(gen->emit_array_address(base.result(), offset, access.type()));
53 } else if (needs_patching) {
54 // we need to patch the offset in the instruction so don't allow
55 // generate_address to try to be smart about emitting the -1.
56 // Otherwise the patching code won't know how to find the
57 // instruction to patch.
58 addr_opr = LIR_OprFact::address(new LIR_Address(base.result(), PATCHED_ADDR, access.type()));
59 } else {
60 addr_opr = LIR_OprFact::address(gen->generate_address(base.result(), offset, 0, 0, access.type()));
61 }
62
63 if (resolve_in_register) {
64 LIR_Opr resolved_addr = gen->new_pointer_register();
65 __ leal(addr_opr, resolved_addr);
66 resolved_addr = LIR_OprFact::address(new LIR_Address(resolved_addr, access.type()));
67 return resolved_addr;
68 } else {
69 return addr_opr;
70 }
71 }
72
73 void BarrierSetC1::store_at(LIRAccess& access, LIR_Opr value) {
74 DecoratorSet decorators = access.decorators();
75 bool in_heap = (decorators & IN_HEAP) != 0;
76 assert(in_heap, "not supported yet");
77
78 LIR_Opr resolved = resolve_address(access, false);
79 access.set_resolved_addr(resolved);
80 store_at_resolved(access, value);
81 }
82
83 void BarrierSetC1::load_at(LIRAccess& access, LIR_Opr result) {
84 DecoratorSet decorators = access.decorators();
85 bool in_heap = (decorators & IN_HEAP) != 0;
86 assert(in_heap, "not supported yet");
87
88 LIR_Opr resolved = resolve_address(access, false);
89 access.set_resolved_addr(resolved);
90 load_at_resolved(access, result);
91 }
92
93 LIR_Opr BarrierSetC1::atomic_cmpxchg_at(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
94 DecoratorSet decorators = access.decorators();
95 bool in_heap = (decorators & IN_HEAP) != 0;
96 assert(in_heap, "not supported yet");
97
98 access.load_address();
99
100 LIR_Opr resolved = resolve_address(access, true);
101 access.set_resolved_addr(resolved);
102 return atomic_cmpxchg_at_resolved(access, cmp_value, new_value);
103 }
104
105 LIR_Opr BarrierSetC1::atomic_xchg_at(LIRAccess& access, LIRItem& value) {
106 DecoratorSet decorators = access.decorators();
107 bool in_heap = (decorators & IN_HEAP) != 0;
108 assert(in_heap, "not supported yet");
109
110 access.load_address();
111
112 LIR_Opr resolved = resolve_address(access, true);
113 access.set_resolved_addr(resolved);
114 return atomic_xchg_at_resolved(access, value);
115 }
116
117 LIR_Opr BarrierSetC1::atomic_add_at(LIRAccess& access, LIRItem& value) {
118 DecoratorSet decorators = access.decorators();
119 bool in_heap = (decorators & IN_HEAP) != 0;
120 assert(in_heap, "not supported yet");
121
122 access.load_address();
123
124 LIR_Opr resolved = resolve_address(access, true);
125 access.set_resolved_addr(resolved);
126 return atomic_add_at_resolved(access, value);
127 }
128
129 void BarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {
130 DecoratorSet decorators = access.decorators();
131 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();
132 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
133 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
134 LIRGenerator* gen = access.gen();
135
136 if (mask_boolean) {
137 value = gen->mask_boolean(access.base().opr(), value, access.access_emit_info());
138 }
139
140 if (is_volatile && os::is_MP()) {
141 __ membar_release();
142 }
143
144 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
145 if (is_volatile && !needs_patching) {
146 gen->volatile_field_store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info());
147 } else {
148 __ store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info(), patch_code);
149 }
150
151 if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {
152 __ membar();
153 }
154 }
155
156 void BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {
157 LIRGenerator *gen = access.gen();
158 DecoratorSet decorators = access.decorators();
159 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();
160 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
161 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
162
163 if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {
164 __ membar();
165 }
166
167 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
168 if (is_volatile && !needs_patching) {
169 gen->volatile_field_load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info());
170 } else {
171 __ load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info(), patch_code);
172 }
173
174 if (is_volatile && os::is_MP()) {
175 __ membar_acquire();
176 }
177
178 /* Normalize boolean value returned by unsafe operation, i.e., value != 0 ? value = true : value false. */
179 if (mask_boolean) {
180 LabelObj* equalZeroLabel = new LabelObj();
181 __ cmp(lir_cond_equal, result, 0);
182 __ branch(lir_cond_equal, T_BOOLEAN, equalZeroLabel->label());
183 __ move(LIR_OprFact::intConst(1), result);
184 __ branch_destination(equalZeroLabel->label());
185 }
186 }
187
188 LIR_Opr BarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
189 LIRGenerator *gen = access.gen();
190 return gen->atomic_cmpxchg(access.type(), access.resolved_addr(), cmp_value, new_value);
191 }
192
193 LIR_Opr BarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {
194 LIRGenerator *gen = access.gen();
195 return gen->atomic_xchg(access.type(), access.resolved_addr(), value);
196 }
197
198 LIR_Opr BarrierSetC1::atomic_add_at_resolved(LIRAccess& access, LIRItem& value) {
199 LIRGenerator *gen = access.gen();
200 return gen->atomic_add(access.type(), access.resolved_addr(), value);
201 }
202
203 void BarrierSetC1::generate_referent_check(LIRAccess& access, LabelObj* cont) {
204 // We might be reading the value of the referent field of a
205 // Reference object in order to attach it back to the live
206 // object graph. If G1 is enabled then we need to record
207 // the value that is being returned in an SATB log buffer.
208 //
209 // We need to generate code similar to the following...
210 //
211 // if (offset == java_lang_ref_Reference::referent_offset) {
212 // if (src != NULL) {
213 // if (klass(src)->reference_type() != REF_NONE) {
214 // pre_barrier(..., value, ...);
215 // }
216 // }
217 // }
218
219 bool gen_pre_barrier = true; // Assume we need to generate pre_barrier.
220 bool gen_offset_check = true; // Assume we need to generate the offset guard.
221 bool gen_source_check = true; // Assume we need to check the src object for null.
222 bool gen_type_check = true; // Assume we need to check the reference_type.
223
224 LIRGenerator *gen = access.gen();
225
226 LIRItem& base = access.base().item();
227 LIR_Opr offset = access.offset().opr();
228
229 if (offset->is_constant()) {
230 LIR_Const* constant = offset->as_constant_ptr();
231 jlong off_con = (constant->type() == T_INT ?
232 (jlong)constant->as_jint() :
233 constant->as_jlong());
234
235
236 if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {
237 // The constant offset is something other than referent_offset.
238 // We can skip generating/checking the remaining guards and
239 // skip generation of the code stub.
240 gen_pre_barrier = false;
241 } else {
242 // The constant offset is the same as referent_offset -
243 // we do not need to generate a runtime offset check.
244 gen_offset_check = false;
245 }
246 }
247
248 // We don't need to generate stub if the source object is an array
249 if (gen_pre_barrier && base.type()->is_array()) {
250 gen_pre_barrier = false;
251 }
252
253 if (gen_pre_barrier) {
254 // We still need to continue with the checks.
255 if (base.is_constant()) {
256 ciObject* src_con = base.get_jobject_constant();
257 guarantee(src_con != NULL, "no source constant");
258
259 if (src_con->is_null_object()) {
260 // The constant src object is null - We can skip
261 // generating the code stub.
262 gen_pre_barrier = false;
263 } else {
264 // Non-null constant source object. We still have to generate
265 // the slow stub - but we don't need to generate the runtime
266 // null object check.
267 gen_source_check = false;
268 }
269 }
270 }
271 if (gen_pre_barrier && !PatchALot) {
272 // Can the klass of object be statically determined to be
273 // a sub-class of Reference?
274 ciType* type = base.value()->declared_type();
275 if ((type != NULL) && type->is_loaded()) {
276 if (type->is_subtype_of(gen->compilation()->env()->Reference_klass())) {
277 gen_type_check = false;
278 } else if (type->is_klass() &&
279 !gen->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {
280 // Not Reference and not Object klass.
281 gen_pre_barrier = false;
282 }
283 }
284 }
285
286 if (gen_pre_barrier) {
287 // We can have generate one runtime check here. Let's start with
288 // the offset check.
289 if (gen_offset_check) {
290 // if (offset != referent_offset) -> continue
291 // If offset is an int then we can do the comparison with the
292 // referent_offset constant; otherwise we need to move
293 // referent_offset into a temporary register and generate
294 // a reg-reg compare.
295
296 LIR_Opr referent_off;
297
298 if (offset->type() == T_INT) {
299 referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);
300 } else {
301 assert(offset->type() == T_LONG, "what else?");
302 referent_off = gen->new_register(T_LONG);
303 __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);
304 }
305 __ cmp(lir_cond_notEqual, offset, referent_off);
306 __ branch(lir_cond_notEqual, offset->type(), cont->label());
307 }
308 if (gen_source_check) {
309 // offset is a const and equals referent offset
310 // if (source == null) -> continue
311 __ cmp(lir_cond_equal, base.result(), LIR_OprFact::oopConst(NULL));
312 __ branch(lir_cond_equal, T_OBJECT, cont->label());
313 }
314 LIR_Opr src_klass = gen->new_register(T_OBJECT);
315 if (gen_type_check) {
316 // We have determined that offset == referent_offset && src != null.
317 // if (src->_klass->_reference_type == REF_NONE) -> continue
318 __ move(new LIR_Address(base.result(), oopDesc::klass_offset_in_bytes(), T_ADDRESS), src_klass);
319 LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);
320 LIR_Opr reference_type = gen->new_register(T_INT);
321 __ move(reference_type_addr, reference_type);
322 __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));
323 __ branch(lir_cond_equal, T_INT, cont->label());
324 }
325 }
326 }