1 /*
2 * Copyright (c) 2018, 2020, 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 "classfile/javaClasses.hpp"
29 #include "gc/shared/c1/barrierSetC1.hpp"
30 #include "utilities/macros.hpp"
31
32 #ifndef PATCHED_ADDR
33 #define PATCHED_ADDR (max_jint)
34 #endif
35
36 #ifdef ASSERT
37 #define __ gen->lir(__FILE__, __LINE__)->
38 #else
39 #define __ gen->lir()->
40 #endif
41
42 LIR_Opr BarrierSetC1::resolve_address(LIRAccess& access, bool resolve_in_register) {
43 DecoratorSet decorators = access.decorators();
44 bool is_array = (decorators & IS_ARRAY) != 0;
45 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
46
47 LIRItem& base = access.base().item();
48 LIR_Opr offset = access.offset().opr();
49 LIRGenerator *gen = access.gen();
50
51 LIR_Opr addr_opr;
52 if (is_array) {
53 addr_opr = LIR_OprFact::address(gen->emit_array_address(base.result(), offset, access.type()));
54 } else if (needs_patching) {
55 // we need to patch the offset in the instruction so don't allow
56 // generate_address to try to be smart about emitting the -1.
57 // Otherwise the patching code won't know how to find the
58 // instruction to patch.
59 addr_opr = LIR_OprFact::address(new LIR_Address(base.result(), PATCHED_ADDR, access.type()));
60 } else {
61 addr_opr = LIR_OprFact::address(gen->generate_address(base.result(), offset, 0, 0, access.type()));
62 }
63
64 if (resolve_in_register) {
65 LIR_Opr resolved_addr = gen->new_pointer_register();
66 if (needs_patching) {
67 __ leal(addr_opr, resolved_addr, lir_patch_normal, access.patch_emit_info());
68 access.clear_decorators(C1_NEEDS_PATCHING);
69 } else {
70 __ leal(addr_opr, resolved_addr);
71 }
72 return LIR_OprFact::address(new LIR_Address(resolved_addr, access.type()));
73 } else {
74 return addr_opr;
75 }
76 }
77
78 void BarrierSetC1::store_at(LIRAccess& access, LIR_Opr value) {
79 DecoratorSet decorators = access.decorators();
80 bool in_heap = (decorators & IN_HEAP) != 0;
81 assert(in_heap, "not supported yet");
82
83 LIR_Opr resolved = resolve_address(access, false);
84 access.set_resolved_addr(resolved);
85 store_at_resolved(access, value);
86 }
87
88 void BarrierSetC1::load_at(LIRAccess& access, LIR_Opr result) {
89 DecoratorSet decorators = access.decorators();
90 bool in_heap = (decorators & IN_HEAP) != 0;
91 assert(in_heap, "not supported yet");
92
93 LIR_Opr resolved = resolve_address(access, false);
94 access.set_resolved_addr(resolved);
95 load_at_resolved(access, result);
96 }
97
98 void BarrierSetC1::load(LIRAccess& access, LIR_Opr result) {
99 DecoratorSet decorators = access.decorators();
100 bool in_heap = (decorators & IN_HEAP) != 0;
101 assert(!in_heap, "consider using load_at");
102 load_at_resolved(access, result);
103 }
104
105 LIR_Opr BarrierSetC1::atomic_cmpxchg_at(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_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_cmpxchg_at_resolved(access, cmp_value, new_value);
115 }
116
117 LIR_Opr BarrierSetC1::atomic_xchg_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_xchg_at_resolved(access, value);
127 }
128
129 LIR_Opr BarrierSetC1::atomic_add_at(LIRAccess& access, LIRItem& value) {
130 DecoratorSet decorators = access.decorators();
131 bool in_heap = (decorators & IN_HEAP) != 0;
132 assert(in_heap, "not supported yet");
133
134 access.load_address();
135
136 LIR_Opr resolved = resolve_address(access, true);
137 access.set_resolved_addr(resolved);
138 return atomic_add_at_resolved(access, value);
139 }
140
141 void BarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {
142 DecoratorSet decorators = access.decorators();
143 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses);
144 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
145 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
146 LIRGenerator* gen = access.gen();
147
148 if (mask_boolean) {
149 value = gen->mask_boolean(access.base().opr(), value, access.access_emit_info());
150 }
151
152 if (is_volatile) {
153 __ membar_release();
154 }
155
156 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
157 if (is_volatile && !needs_patching) {
158 gen->volatile_field_store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info());
159 } else {
160 __ store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info(), patch_code);
161 }
162
163 if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {
164 __ membar();
165 }
166 }
167
168 void BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {
169 LIRGenerator *gen = access.gen();
170 DecoratorSet decorators = access.decorators();
171 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses);
172 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
173 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
174 bool in_native = (decorators & IN_NATIVE) != 0;
175
176 if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {
177 __ membar();
178 }
179
180 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
181 if (in_native) {
182 __ move_wide(access.resolved_addr()->as_address_ptr(), result);
183 } else if (is_volatile && !needs_patching) {
184 gen->volatile_field_load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info());
185 } else {
186 __ load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info(), patch_code);
187 }
188
189 if (is_volatile) {
190 __ membar_acquire();
191 }
192
193 /* Normalize boolean value returned by unsafe operation, i.e., value != 0 ? value = true : value false. */
194 if (mask_boolean) {
195 LabelObj* equalZeroLabel = new LabelObj();
196 __ cmp(lir_cond_equal, result, 0);
197 __ branch(lir_cond_equal, equalZeroLabel->label());
198 __ move(LIR_OprFact::intConst(1), result);
199 __ branch_destination(equalZeroLabel->label());
200 }
201 }
202
203 LIR_Opr BarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
204 LIRGenerator *gen = access.gen();
205 return gen->atomic_cmpxchg(access.type(), access.resolved_addr(), cmp_value, new_value);
206 }
207
208 LIR_Opr BarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {
209 LIRGenerator *gen = access.gen();
210 return gen->atomic_xchg(access.type(), access.resolved_addr(), value);
211 }
212
213 LIR_Opr BarrierSetC1::atomic_add_at_resolved(LIRAccess& access, LIRItem& value) {
214 LIRGenerator *gen = access.gen();
215 return gen->atomic_add(access.type(), access.resolved_addr(), value);
216 }
217
218 void BarrierSetC1::generate_referent_check(LIRAccess& access, LabelObj* cont) {
219 // We might be reading the value of the referent field of a
220 // Reference object in order to attach it back to the live
221 // object graph. If G1 is enabled then we need to record
222 // the value that is being returned in an SATB log buffer.
223 //
224 // We need to generate code similar to the following...
225 //
226 // if (offset == java_lang_ref_Reference::referent_offset()) {
227 // if (src != NULL) {
228 // if (klass(src)->reference_type() != REF_NONE) {
229 // pre_barrier(..., value, ...);
230 // }
231 // }
232 // }
233
234 bool gen_pre_barrier = true; // Assume we need to generate pre_barrier.
235 bool gen_offset_check = true; // Assume we need to generate the offset guard.
236 bool gen_source_check = true; // Assume we need to check the src object for null.
237 bool gen_type_check = true; // Assume we need to check the reference_type.
238
239 LIRGenerator *gen = access.gen();
240
241 LIRItem& base = access.base().item();
242 LIR_Opr offset = access.offset().opr();
243
244 if (offset->is_constant()) {
245 LIR_Const* constant = offset->as_constant_ptr();
246 jlong off_con = (constant->type() == T_INT ?
247 (jlong)constant->as_jint() :
248 constant->as_jlong());
249
250
251 if (off_con != (jlong) java_lang_ref_Reference::referent_offset()) {
252 // The constant offset is something other than referent_offset.
253 // We can skip generating/checking the remaining guards and
254 // skip generation of the code stub.
255 gen_pre_barrier = false;
256 } else {
257 // The constant offset is the same as referent_offset -
258 // we do not need to generate a runtime offset check.
259 gen_offset_check = false;
260 }
261 }
262
263 // We don't need to generate stub if the source object is an array
264 if (gen_pre_barrier && base.type()->is_array()) {
265 gen_pre_barrier = false;
266 }
267
268 if (gen_pre_barrier) {
269 // We still need to continue with the checks.
270 if (base.is_constant()) {
271 ciObject* src_con = base.get_jobject_constant();
272 guarantee(src_con != NULL, "no source constant");
273
274 if (src_con->is_null_object()) {
275 // The constant src object is null - We can skip
276 // generating the code stub.
277 gen_pre_barrier = false;
278 } else {
279 // Non-null constant source object. We still have to generate
280 // the slow stub - but we don't need to generate the runtime
281 // null object check.
282 gen_source_check = false;
283 }
284 }
285 }
286 if (gen_pre_barrier && !PatchALot) {
287 // Can the klass of object be statically determined to be
288 // a sub-class of Reference?
289 ciType* type = base.value()->declared_type();
290 if ((type != NULL) && type->is_loaded()) {
291 if (type->is_subtype_of(gen->compilation()->env()->Reference_klass())) {
292 gen_type_check = false;
293 } else if (type->is_klass() &&
294 !gen->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {
295 // Not Reference and not Object klass.
296 gen_pre_barrier = false;
297 }
298 }
299 }
300
301 if (gen_pre_barrier) {
302 // We can have generate one runtime check here. Let's start with
303 // the offset check.
304 // Allocate temp register to base and load it here, otherwise
305 // control flow below may confuse register allocator.
306 LIR_Opr base_reg = gen->new_register(T_OBJECT);
307 __ move(base.result(), base_reg);
308 if (gen_offset_check) {
309 // if (offset != referent_offset) -> continue
310 // If offset is an int then we can do the comparison with the
311 // referent_offset constant; otherwise we need to move
312 // referent_offset into a temporary register and generate
313 // a reg-reg compare.
314
315 LIR_Opr referent_off;
316
317 if (offset->type() == T_INT) {
318 referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset());
319 } else {
320 assert(offset->type() == T_LONG, "what else?");
321 referent_off = gen->new_register(T_LONG);
322 __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset()), referent_off);
323 }
324 __ cmp(lir_cond_notEqual, offset, referent_off);
325 __ branch(lir_cond_notEqual, cont->label());
326 }
327 if (gen_source_check) {
328 // offset is a const and equals referent offset
329 // if (source == null) -> continue
330 __ cmp(lir_cond_equal, base_reg, LIR_OprFact::oopConst(NULL));
331 __ branch(lir_cond_equal, cont->label());
332 }
333 LIR_Opr src_klass = gen->new_register(T_METADATA);
334 if (gen_type_check) {
335 // We have determined that offset == referent_offset && src != null.
336 // if (src->_klass->_reference_type == REF_NONE) -> continue
337 gen->load_klass(base_reg, src_klass, NULL);
338 LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);
339 LIR_Opr reference_type = gen->new_register(T_INT);
340 __ move(reference_type_addr, reference_type);
341 __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));
342 __ branch(lir_cond_equal, cont->label());
343 }
344 }
345 }