1 /*
2 * Copyright (c) 2017, 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/c1BarrierSetCodeGen.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 __ lir_generator->lir(__FILE__, __LINE__)->
37 #else
38 #define __ lir_generator->lir()->
39 #endif
40
41 LIR_Opr C1BarrierSetCodeGen::resolve_address(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
42 LIRItem& base, LIR_Opr offset, bool resolve_in_register) {
43 bool on_array = (decorators & C1_ACCESS_ON_ARRAY) != 0;
44 bool is_oop = type == T_OBJECT || type == T_ARRAY;
45 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
46 LIR_Opr addr;
47 if (on_array) {
48 addr = LIR_OprFact::address(lir_generator->emit_array_address(base.result(), offset, type, is_oop));
49 } else if (needs_patching) {
50 // we need to patch the offset in the instruction so don't allow
51 // generate_address to try to be smart about emitting the -1.
52 // Otherwise the patching code won't know how to find the
53 // instruction to patch.
54 addr = LIR_OprFact::address(new LIR_Address(base.result(), PATCHED_ADDR, type));
55 } else {
56 addr = LIR_OprFact::address(lir_generator->generate_address(base.result(), offset, 0, 0, type));
57 }
58
59 if (resolve_in_register) {
60 LIR_Opr resolved_addr = lir_generator->new_pointer_register();
61 __ leal(addr, resolved_addr);
62 resolved_addr = LIR_OprFact::address(new LIR_Address(resolved_addr, type));
63 return resolved_addr;
64 } else {
65 return addr;
66 }
67 }
68
69 void C1BarrierSetCodeGen::store_at(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
70 LIRItem& base, LIR_Opr offset, LIR_Opr value,
71 CodeEmitInfo* patch_info, CodeEmitInfo* store_emit_info) {
72 LIR_Opr addr = resolve_address(lir_generator, decorators, type, base, offset, false);
73 store_at_resolved(lir_generator, decorators, type, addr, base, offset, value, patch_info, store_emit_info);
74 }
75
76 LIR_Opr C1BarrierSetCodeGen::load_at(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
77 LIRItem& base, LIR_Opr offset,
78 CodeEmitInfo* patch_info, CodeEmitInfo* load_emit_info) {
79 LIR_Opr addr = resolve_address(lir_generator, decorators, type, base, offset, false);
80 return load_at_resolved(lir_generator, decorators, type, addr, base, offset, patch_info, load_emit_info);
81 }
82
83 LIR_Opr C1BarrierSetCodeGen::cas_at(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
84 LIRItem& base, LIRItem& offset, LIRItem& cmp_value, LIRItem& new_value) {
85 base.load_item();
86 offset.load_nonconstant();
87
88 LIR_Opr addr = resolve_address(lir_generator, decorators, type, base, offset.result(), true);
89 return cas_at_resolved(lir_generator, decorators, type, addr, base, offset, cmp_value, new_value);
90 }
91
92 LIR_Opr C1BarrierSetCodeGen::swap_at(LIRGenerator* lir_generator, C1DecoratorSet decorators, BasicType type,
93 LIRItem& base, LIRItem& offset, LIRItem& value) {
94 base.load_item();
95 offset.load_nonconstant();
96
97 LIR_Opr addr = resolve_address(lir_generator, decorators, type, base, offset.result(), true);
98 return swap_at_resolved(lir_generator, decorators, type, addr, base, offset, value);
99 }
100
101 LIR_Opr C1BarrierSetCodeGen::add_at(LIRGenerator* lir_generator, C1DecoratorSet decorators, BasicType type,
102 LIRItem& base, LIRItem& offset, LIRItem& value) {
103 base.load_item();
104 offset.load_nonconstant();
105
106 LIR_Opr addr = resolve_address(lir_generator, decorators, type, base, offset.result(), true);
107 return add_at_resolved(lir_generator, decorators, type, addr, base, offset, value);
108 }
109
110 void C1BarrierSetCodeGen::store_at_resolved(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
111 LIR_Opr addr, LIRItem& base, LIR_Opr offset, LIR_Opr value,
112 CodeEmitInfo* patch_info, CodeEmitInfo* store_emit_info) {
113 bool is_volatile = (((decorators & C1_MO_VOLATILE) != 0) || AlwaysAtomicAccesses) && os::is_MP();
114 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
115 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
116
117 if (mask_boolean) {
118 value = lir_generator->mask_boolean(base.result(), value, store_emit_info);
119 }
120
121 if (is_volatile && os::is_MP()) {
122 __ membar_release();
123 }
124
125 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
126 if (is_volatile && !needs_patching) {
127 lir_generator->volatile_field_store(value, addr->as_address_ptr(), store_emit_info);
128 } else {
129 __ store(value, addr->as_address_ptr(), store_emit_info, patch_code);
130 }
131
132 if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {
133 __ membar();
134 }
135 }
136
137 LIR_Opr C1BarrierSetCodeGen::load_at_resolved(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
138 LIR_Opr addr, LIRItem& base, LIR_Opr offset,
139 CodeEmitInfo* patch_info, CodeEmitInfo* load_emit_info) {
140 bool is_volatile = (((decorators & C1_MO_VOLATILE) != 0) || AlwaysAtomicAccesses) && os::is_MP();
141 bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
142 bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
143 BasicType val_bt = as_BasicType(as_ValueType(type));
144
145 LIR_Opr result = lir_generator->new_register(val_bt);
146
147 if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {
148 __ membar();
149 }
150
151 LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
152 if (is_volatile && !needs_patching) {
153 lir_generator->volatile_field_load(addr->as_address_ptr(), result, load_emit_info);
154 } else {
155 __ load(addr->as_address_ptr(), result, load_emit_info, patch_code);
156 }
157
158 if (is_volatile && os::is_MP()) {
159 __ membar_acquire();
160 }
161
162 /* Normalize boolean value returned by unsafe operation, i.e., value != 0 ? value = true : value false. */
163 if (mask_boolean) {
164 LabelObj* equalZeroLabel = new LabelObj();
165 __ cmp(lir_cond_equal, result, 0);
166 __ branch(lir_cond_equal, T_BOOLEAN, equalZeroLabel->label());
167 __ move(LIR_OprFact::intConst(1), result);
168 __ branch_destination(equalZeroLabel->label());
169 }
170
171 return result;
172 }
173
174 LIR_Opr C1BarrierSetCodeGen::cas_at_resolved(LIRGenerator *lir_generator, C1DecoratorSet decorators, BasicType type,
175 LIR_Opr addr, LIRItem& base, LIRItem& offset, LIRItem& cmp_value, LIRItem& new_value) {
176 BasicType val_bt = as_BasicType(as_ValueType(type));
177 return lir_generator->cas(val_bt, addr, cmp_value, new_value);
178 }
179
180 LIR_Opr C1BarrierSetCodeGen::swap_at_resolved(LIRGenerator* lir_generator, C1DecoratorSet decorators, BasicType type,
181 LIR_Opr addr, LIRItem& base, LIRItem& offset, LIRItem& value) {
182 BasicType val_bt = as_BasicType(as_ValueType(type));
183 return lir_generator->swap(val_bt, addr, value);
184 }
185
186 LIR_Opr C1BarrierSetCodeGen::add_at_resolved(LIRGenerator* lir_generator, C1DecoratorSet decorators, BasicType type,
187 LIR_Opr addr, LIRItem& base, LIRItem& offset, LIRItem& value) {
188 BasicType val_bt = as_BasicType(as_ValueType(type));
189 return lir_generator->add(val_bt, addr, value);
190 }
191
192 void C1BarrierSetCodeGen::generate_referent_check(LIRGenerator* lir_generator, LIRItem& base, LIR_Opr offset, LabelObj* cont) {
193 // We might be reading the value of the referent field of a
194 // Reference object in order to attach it back to the live
195 // object graph. If G1 is enabled then we need to record
196 // the value that is being returned in an SATB log buffer.
197 //
198 // We need to generate code similar to the following...
199 //
200 // if (offset == java_lang_ref_Reference::referent_offset) {
201 // if (src != NULL) {
202 // if (klass(src)->reference_type() != REF_NONE) {
203 // pre_barrier(..., value, ...);
204 // }
205 // }
206 // }
207
208 bool gen_pre_barrier = true; // Assume we need to generate pre_barrier.
209 bool gen_offset_check = true; // Assume we need to generate the offset guard.
210 bool gen_source_check = true; // Assume we need to check the src object for null.
211 bool gen_type_check = true; // Assume we need to check the reference_type.
212
213 if (offset->is_constant()) {
214 LIR_Const* constant = offset->as_constant_ptr();
215 jlong off_con = (constant->type() == T_INT ?
216 (jlong)constant->as_jint() :
217 constant->as_jlong());
218
219
220 if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {
221 // The constant offset is something other than referent_offset.
222 // We can skip generating/checking the remaining guards and
223 // skip generation of the code stub.
224 gen_pre_barrier = false;
225 } else {
226 // The constant offset is the same as referent_offset -
227 // we do not need to generate a runtime offset check.
228 gen_offset_check = false;
229 }
230 }
231
232 // We don't need to generate stub if the source object is an array
233 if (gen_pre_barrier && base.type()->is_array()) {
234 gen_pre_barrier = false;
235 }
236
237 if (gen_pre_barrier) {
238 // We still need to continue with the checks.
239 if (base.is_constant()) {
240 ciObject* src_con = base.get_jobject_constant();
241 guarantee(src_con != NULL, "no source constant");
242
243 if (src_con->is_null_object()) {
244 // The constant src object is null - We can skip
245 // generating the code stub.
246 gen_pre_barrier = false;
247 } else {
248 // Non-null constant source object. We still have to generate
249 // the slow stub - but we don't need to generate the runtime
250 // null object check.
251 gen_source_check = false;
252 }
253 }
254 }
255 if (gen_pre_barrier && !PatchALot) {
256 // Can the klass of object be statically determined to be
257 // a sub-class of Reference?
258 ciType* type = base.value()->declared_type();
259 if ((type != NULL) && type->is_loaded()) {
260 if (type->is_subtype_of(lir_generator->compilation()->env()->Reference_klass())) {
261 gen_type_check = false;
262 } else if (type->is_klass() &&
263 !lir_generator->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {
264 // Not Reference and not Object klass.
265 gen_pre_barrier = false;
266 }
267 }
268 }
269
270 if (gen_pre_barrier) {
271 // We can have generate one runtime check here. Let's start with
272 // the offset check.
273 if (gen_offset_check) {
274 // if (offset != referent_offset) -> continue
275 // If offset is an int then we can do the comparison with the
276 // referent_offset constant; otherwise we need to move
277 // referent_offset into a temporary register and generate
278 // a reg-reg compare.
279
280 LIR_Opr referent_off;
281
282 if (offset->type() == T_INT) {
283 referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);
284 } else {
285 assert(offset->type() == T_LONG, "what else?");
286 referent_off = lir_generator->new_register(T_LONG);
287 __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);
288 }
289 __ cmp(lir_cond_notEqual, offset, referent_off);
290 __ branch(lir_cond_notEqual, offset->type(), cont->label());
291 }
292 if (gen_source_check) {
293 // offset is a const and equals referent offset
294 // if (source == null) -> continue
295 __ cmp(lir_cond_equal, base.result(), LIR_OprFact::oopConst(NULL));
296 __ branch(lir_cond_equal, T_OBJECT, cont->label());
297 }
298 LIR_Opr src_klass = lir_generator->new_register(T_OBJECT);
299 if (gen_type_check) {
300 // We have determined that offset == referent_offset && src != null.
301 // if (src->_klass->_reference_type == REF_NONE) -> continue
302 __ move(new LIR_Address(base.result(), oopDesc::klass_offset_in_bytes(), T_ADDRESS), src_klass);
303 LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);
304 LIR_Opr reference_type = lir_generator->new_register(T_INT);
305 __ move(reference_type_addr, reference_type);
306 __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));
307 __ branch(lir_cond_equal, T_INT, cont->label());
308 }
309 }
310 }