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 void BarrierSetC1::load(LIRAccess& access, LIR_Opr result) {
94 DecoratorSet decorators = access.decorators();
95 bool in_heap = (decorators & IN_HEAP) != 0;
96 assert(!in_heap, "consider using load_at");
97 load_at_resolved(access, result);
98 }
99
100 LIR_Opr BarrierSetC1::atomic_cmpxchg_at(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
101 DecoratorSet decorators = access.decorators();
102 bool in_heap = (decorators & IN_HEAP) != 0;
103 assert(in_heap, "not supported yet");
104
105 access.load_address();
106
107 LIR_Opr resolved = resolve_address(access, true);
108 access.set_resolved_addr(resolved);
109 return atomic_cmpxchg_at_resolved(access, cmp_value, new_value);
110 }
111
112 LIR_Opr BarrierSetC1::atomic_xchg_at(LIRAccess& access, LIRItem& value) {
113 DecoratorSet decorators = access.decorators();
114 bool in_heap = (decorators & IN_HEAP) != 0;
115 assert(in_heap, "not supported yet");
116
117 access.load_address();
118
119 LIR_Opr resolved = resolve_address(access, true);
120 access.set_resolved_addr(resolved);
121 return atomic_xchg_at_resolved(access, value);
122 }
123
124 LIR_Opr BarrierSetC1::atomic_add_at(LIRAccess& access, LIRItem& value) {
125 DecoratorSet decorators = access.decorators();
126 bool in_heap = (decorators & IN_HEAP) != 0;
127 assert(in_heap, "not supported yet");
128
129 access.load_address();
130
131 LIR_Opr resolved = resolve_address(access, true);
132 access.set_resolved_addr(resolved);
133 return atomic_add_at_resolved(access, value);
134 }
135
136 void BarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {
137 DecoratorSet decorators = access.decorators();
138 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();
139 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
140 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
141 LIRGenerator* gen = access.gen();
142
143 if (mask_boolean) {
144 value = gen->mask_boolean(access.base().opr(), value, access.access_emit_info());
145 }
146
147 if (is_volatile && os::is_MP()) {
148 __ membar_release();
149 }
150
151 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
152 if (is_volatile && !needs_patching) {
153 gen->volatile_field_store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info());
154 } else {
155 __ store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info(), patch_code);
156 }
157
158 if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {
159 __ membar();
160 }
161 }
162
163 void BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {
164 LIRGenerator *gen = access.gen();
165 DecoratorSet decorators = access.decorators();
166 bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();
167 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
168 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
169 bool in_native = (decorators & IN_NATIVE) != 0;
170
171 if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {
172 __ membar();
173 }
174
175 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
176 if (in_native) {
177 __ move_wide(access.resolved_addr()->as_address_ptr(), result);
178 } else if (is_volatile && !needs_patching) {
179 gen->volatile_field_load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info());
180 } else {
181 __ load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info(), patch_code);
182 }
183
184 if (is_volatile && os::is_MP()) {
185 __ membar_acquire();
186 }
187
188 /* Normalize boolean value returned by unsafe operation, i.e., value != 0 ? value = true : value false. */
189 if (mask_boolean) {
190 LabelObj* equalZeroLabel = new LabelObj();
191 __ cmp(lir_cond_equal, result, 0);
192 __ branch(lir_cond_equal, T_BOOLEAN, equalZeroLabel->label());
193 __ move(LIR_OprFact::intConst(1), result);
194 __ branch_destination(equalZeroLabel->label());
195 }
196 }
197
198 LIR_Opr BarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
199 LIRGenerator *gen = access.gen();
200 return gen->atomic_cmpxchg(access.type(), access.resolved_addr(), cmp_value, new_value);
201 }
202
203 LIR_Opr BarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {
204 LIRGenerator *gen = access.gen();
205 return gen->atomic_xchg(access.type(), access.resolved_addr(), value);
206 }
207
208 LIR_Opr BarrierSetC1::atomic_add_at_resolved(LIRAccess& access, LIRItem& value) {
209 LIRGenerator *gen = access.gen();
210 return gen->atomic_add(access.type(), access.resolved_addr(), value);
211 }
212
213 void BarrierSetC1::generate_referent_check(LIRAccess& access, LabelObj* cont) {
214 // We might be reading the value of the referent field of a
215 // Reference object in order to attach it back to the live
216 // object graph. If G1 is enabled then we need to record
217 // the value that is being returned in an SATB log buffer.
218 //
219 // We need to generate code similar to the following...
220 //
221 // if (offset == java_lang_ref_Reference::referent_offset) {
222 // if (src != NULL) {
223 // if (klass(src)->reference_type() != REF_NONE) {
224 // pre_barrier(..., value, ...);
225 // }
226 // }
227 // }
228
229 bool gen_pre_barrier = true; // Assume we need to generate pre_barrier.
230 bool gen_offset_check = true; // Assume we need to generate the offset guard.
231 bool gen_source_check = true; // Assume we need to check the src object for null.
232 bool gen_type_check = true; // Assume we need to check the reference_type.
233
234 LIRGenerator *gen = access.gen();
235
236 LIRItem& base = access.base().item();
237 LIR_Opr offset = access.offset().opr();
238
239 if (offset->is_constant()) {
240 LIR_Const* constant = offset->as_constant_ptr();
241 jlong off_con = (constant->type() == T_INT ?
242 (jlong)constant->as_jint() :
243 constant->as_jlong());
244
245
246 if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {
247 // The constant offset is something other than referent_offset.
248 // We can skip generating/checking the remaining guards and
249 // skip generation of the code stub.
250 gen_pre_barrier = false;
251 } else {
252 // The constant offset is the same as referent_offset -
253 // we do not need to generate a runtime offset check.
254 gen_offset_check = false;
255 }
256 }
257
258 // We don't need to generate stub if the source object is an array
259 if (gen_pre_barrier && base.type()->is_array()) {
260 gen_pre_barrier = false;
261 }
262
263 if (gen_pre_barrier) {
264 // We still need to continue with the checks.
265 if (base.is_constant()) {
266 ciObject* src_con = base.get_jobject_constant();
267 guarantee(src_con != NULL, "no source constant");
268
269 if (src_con->is_null_object()) {
270 // The constant src object is null - We can skip
271 // generating the code stub.
272 gen_pre_barrier = false;
273 } else {
274 // Non-null constant source object. We still have to generate
275 // the slow stub - but we don't need to generate the runtime
276 // null object check.
277 gen_source_check = false;
278 }
279 }
280 }
281 if (gen_pre_barrier && !PatchALot) {
282 // Can the klass of object be statically determined to be
283 // a sub-class of Reference?
284 ciType* type = base.value()->declared_type();
285 if ((type != NULL) && type->is_loaded()) {
286 if (type->is_subtype_of(gen->compilation()->env()->Reference_klass())) {
287 gen_type_check = false;
288 } else if (type->is_klass() &&
289 !gen->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {
290 // Not Reference and not Object klass.
291 gen_pre_barrier = false;
292 }
293 }
294 }
295
296 if (gen_pre_barrier) {
297 // We can have generate one runtime check here. Let's start with
298 // the offset check.
299 if (gen_offset_check) {
300 // if (offset != referent_offset) -> continue
301 // If offset is an int then we can do the comparison with the
302 // referent_offset constant; otherwise we need to move
303 // referent_offset into a temporary register and generate
304 // a reg-reg compare.
305
306 LIR_Opr referent_off;
307
308 if (offset->type() == T_INT) {
309 referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);
310 } else {
311 assert(offset->type() == T_LONG, "what else?");
312 referent_off = gen->new_register(T_LONG);
313 __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);
314 }
315 __ cmp(lir_cond_notEqual, offset, referent_off);
316 __ branch(lir_cond_notEqual, offset->type(), cont->label());
317 }
318 if (gen_source_check) {
319 // offset is a const and equals referent offset
320 // if (source == null) -> continue
321 __ cmp(lir_cond_equal, base.result(), LIR_OprFact::oopConst(NULL));
322 __ branch(lir_cond_equal, T_OBJECT, cont->label());
323 }
324 LIR_Opr src_klass = gen->new_register(T_OBJECT);
325 if (gen_type_check) {
326 // We have determined that offset == referent_offset && src != null.
327 // if (src->_klass->_reference_type == REF_NONE) -> continue
328 __ move(new LIR_Address(base.result(), oopDesc::klass_offset_in_bytes(), T_ADDRESS), src_klass);
329 LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);
330 LIR_Opr reference_type = gen->new_register(T_INT);
331 __ move(reference_type_addr, reference_type);
332 __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));
333 __ branch(lir_cond_equal, T_INT, cont->label());
334 }
335 }
336 }