1 /*
2 * Copyright (c) 2018, 2021, Red Hat, Inc. 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 #ifndef SHARE_GC_SHENANDOAH_C2_SHENANDOAHBARRIERSETC2_HPP
26 #define SHARE_GC_SHENANDOAH_C2_SHENANDOAHBARRIERSETC2_HPP
27
28 #include "gc/shared/c2/barrierSetC2.hpp"
29
30 static const uint8_t ShenandoahBitStrong = 1 << 0; // Barrier: LRB, strong
31 static const uint8_t ShenandoahBitWeak = 1 << 1; // Barrier: LRB, weak
32 static const uint8_t ShenandoahBitPhantom = 1 << 2; // Barrier: LRB, phantom
33 static const uint8_t ShenandoahBitKeepAlive = 1 << 3; // Barrier: KeepAlive (SATB for stores, KA for loads)
34 static const uint8_t ShenandoahBitCardMark = 1 << 4; // Barrier: CM
35 static const uint8_t ShenandoahBitNotNull = 1 << 5; // Metadata: src/dst is definitely not null
36 static const uint8_t ShenandoahBitNative = 1 << 6; // Metadata: access is in native, not in heap
37 static const uint8_t ShenandoahBitElided = 1 << 7; // Metadata: some part of the barrier is elided
38
39 // Barrier data that implies real barriers, not additional metadata.
40 static const uint8_t ShenandoahBitsReal = ShenandoahBitStrong | ShenandoahBitWeak | ShenandoahBitPhantom |
41 ShenandoahBitKeepAlive |
42 ShenandoahBitCardMark;
43
44 class MachNode;
45 class ShenandoahBarrierStubC2;
46
47 class ShenandoahBarrierSetC2State : public BarrierSetC2State {
48 GrowableArray<ShenandoahBarrierStubC2*>* _stubs;
49 int _trampoline_stubs_count;
50 int _stubs_start_offset;
51 int _stubs_current_total_size;
52
53 public:
54 explicit ShenandoahBarrierSetC2State(Arena* comp_arena);
55
56 bool needs_liveness_data(const MachNode* mach) const override;
57 bool needs_livein_data() const override;
58
59 GrowableArray<ShenandoahBarrierStubC2*>* stubs() {
60 return _stubs;
61 }
62
63 void inc_trampoline_stubs_count() {
64 assert(_trampoline_stubs_count != INT_MAX, "Overflow");
65 ++_trampoline_stubs_count;
66 }
67
68 int trampoline_stubs_count() {
69 return _trampoline_stubs_count;
70 }
71
72 void set_stubs_start_offset(int offset) {
73 _stubs_start_offset = offset;
74 }
75
76 int stubs_start_offset() {
77 return _stubs_start_offset;
78 }
79
80 int inc_stubs_current_total_size(int size) {
81 _stubs_current_total_size += size;
82 return _stubs_current_total_size;
83 }
84
85 int stubs_current_total_size() {
86 return _stubs_current_total_size;
87 }
88 };
89
90 class ShenandoahBarrierSetC2 : public BarrierSetC2 {
91
92 static bool clone_needs_barrier(const TypeOopPtr* src_type, bool& is_oop_array);
93
94 static bool can_remove_load_barrier(Node* node);
95
96 static uint8_t refine_load(Node* node, uint8_t bd);
97 static uint8_t refine_store(Node* node, uint8_t bd);
98
99 static bool is_Load(int opcode);
100 static bool is_Store(int opcode);
101 static bool is_LoadStore(int opcode);
102
103 protected:
104 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
105 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
106 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
107 Node* new_val, const Type* val_type) const;
108 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
109 Node* new_val, const Type* value_type) const;
110 virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
111
112 public:
113 // This is the entry-point for the backend to perform accesses through the Access API.
114 virtual void clone(GraphKit* kit, Node* src_base, Node* dst_base, Node* size, bool is_array) const;
115 virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const;
116
117 // These are general helper methods used by C2
118 virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone,
119 bool is_clone_instance, ArrayCopyPhase phase) const;
120
121 // Support for macro expanded GC barriers
122 virtual void eliminate_gc_barrier(PhaseIterGVN* macro, Node* node) const;
123 virtual void eliminate_gc_barrier_data(Node* node) const;
124
125 // Allow barrier sets to have shared state that is preserved across a compilation unit.
126 // This could for example comprise macro nodes to be expanded during macro expansion.
127 virtual void* create_barrier_state(Arena* comp_arena) const;
128
129 #ifdef ASSERT
130 virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const;
131 static void verify_gc_barrier_assert(bool cond, const char* msg, uint8_t bd, Node* n);
132 #endif
133
134 virtual int estimate_stub_size() const;
135 virtual void emit_stubs(CodeBuffer& cb) const;
136 virtual void late_barrier_analysis() const {
137 compute_liveness_at_stubs();
138 analyze_dominating_barriers();
139 }
140
141 virtual void elide_dominated_barrier(MachNode* mach, MachNode* dominator) const;
142 virtual void analyze_dominating_barriers() const;
143 virtual void final_refinement(Compile* C) const;
144
145 virtual uint estimated_barrier_size(const Node* node) const;
146
147 static void print_barrier_data(outputStream* os, uint8_t data);
148 };
149
150 class ShenandoahBarrierStubC2 : public BarrierStubC2 {
151 Register _obj;
152 Address const _addr;
153 Register const _tmp1;
154 Register const _tmp2;
155 const bool _do_load;
156 const bool _narrow;
157 const bool _needs_load_ref_barrier;
158 const bool _needs_load_ref_weak_barrier;
159 const bool _needs_keep_alive_barrier;
160 bool _needs_far_jump;
161
162 static void register_stub(ShenandoahBarrierStubC2* stub);
163
164 int available_gp_registers();
165 bool is_live_register(Register reg);
166 bool is_special_register(Register reg);
167 Register select_temp_register(bool& selected_live, Register skip_reg1 = noreg, Register skip_reg2 = noreg);
168
169 void maybe_far_jump_if_zero(MacroAssembler& masm, Register reg);
170
171 void patchable_jump(MacroAssembler& masm, char gc_state, bool jump_when_state, Register tmp1, Register tmp2, Label* L_target);
172
173 void patchable_jump_if_gc_state(MacroAssembler& masm, const char gc_state, Register tmp1, Register tmp2, Label* L_target) {
174 patchable_jump(masm, gc_state, true, tmp1, tmp2, L_target);
175 }
176 void patchable_jump_if_not_gc_state(MacroAssembler& masm, const char gc_state, Register tmp1, Register tmp2, Label* L_target) {
177 patchable_jump(masm, gc_state, false, tmp1, tmp2, L_target);
178 }
179
180 void enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp1, Register tmp2);
181
182 void keepalive(MacroAssembler& masm, Label* L_done);
183 void lrb(MacroAssembler& masm);
184
185 static void cardtable(MacroAssembler& masm, Address addr, Register tmp1, Register tmp2);
186
187 address keepalive_runtime_entry_addr();
188 address lrb_runtime_entry_addr();
189
190 static ShenandoahBarrierStubC2* create(const MachNode* node, Register obj, Address addr, Register tmp1, Register tmp2, bool narrow, bool do_load);
191 void post_init();
192
193 ShenandoahBarrierStubC2(const MachNode* node, Register obj, Address addr, Register tmp1, Register tmp2, bool narrow, bool do_load) :
194 BarrierStubC2(node),
195 _obj(obj),
196 _addr(addr),
197 _tmp1(tmp1),
198 _tmp2(tmp2),
199 _do_load(do_load),
200 _narrow(narrow),
201 _needs_load_ref_barrier(needs_load_ref_barrier(node)),
202 _needs_load_ref_weak_barrier(needs_load_ref_barrier_weak(node)),
203 _needs_keep_alive_barrier(needs_keep_alive_barrier(node)),
204 _needs_far_jump() {
205 assert(!_narrow || is_heap_access(node), "Only heap accesses can be narrow");
206 if (_tmp1 != noreg && _tmp2 != noreg) {
207 assert_different_registers(_tmp1, _tmp2, _obj, _addr.base(), _addr.index());
208 } else {
209 assert(_tmp1 == _tmp2, "should both be noreg");
210 assert_different_registers(_obj, _addr.base(), _addr.index());
211 }
212 post_init();
213 }
214
215 static bool is_heap_access(const MachNode* node) {
216 return (node->barrier_data() & ShenandoahBitNative) == 0;
217 }
218 static bool needs_load_ref_barrier(const MachNode* node) {
219 return (node->barrier_data() & (ShenandoahBitStrong | ShenandoahBitWeak | ShenandoahBitPhantom)) != 0;
220 }
221 static bool needs_load_ref_barrier_weak(const MachNode* node) {
222 return (node->barrier_data() & (ShenandoahBitWeak | ShenandoahBitPhantom)) != 0;
223 }
224 static bool needs_keep_alive_barrier(const MachNode* node) {
225 return (node->barrier_data() & ShenandoahBitKeepAlive) != 0;
226 }
227 static bool needs_card_barrier(const MachNode* node) {
228 return (node->barrier_data() & ShenandoahBitCardMark) != 0;
229 }
230
231 public:
232 static bool needs_slow_barrier(const MachNode* node) {
233 return needs_load_ref_barrier(node) || needs_keep_alive_barrier(node);
234 }
235
236 static void load_post(MacroAssembler* masm, const MachNode* node, Register obj, Address addr, Register tmp1, Register tmp2, bool narrow);
237 static void store_pre(MacroAssembler* masm, const MachNode* node, Address addr, Register tmp1, Register tmp2, Register tmp3, bool narrow);
238 static void store_post(MacroAssembler* masm, const MachNode* node, Address addr, Register tmp1, Register tmp2);
239 static void load_store_pre(MacroAssembler* masm, const MachNode* node, Address addr, Register tmp1, Register tmp2, Register tmp3, bool narrow);
240 static void load_store_post(MacroAssembler* masm, const MachNode* node, Address addr, Register tmp1, Register tmp2);
241
242 void emit_code(MacroAssembler& masm);
243 };
244 #endif // SHARE_GC_SHENANDOAH_C2_SHENANDOAHBARRIERSETC2_HPP