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: 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
52 public:
53 explicit ShenandoahBarrierSetC2State(Arena* comp_arena);
54
55 bool needs_liveness_data(const MachNode* mach) const override;
56 bool needs_livein_data() const override;
57
58 GrowableArray<ShenandoahBarrierStubC2*>* stubs() {
59 return _stubs;
60 }
61
62 void inc_trampoline_stubs_count() {
63 assert(_trampoline_stubs_count != INT_MAX, "Overflow");
64 ++_trampoline_stubs_count;
65 }
66
67 int trampoline_stubs_count() {
68 return _trampoline_stubs_count;
69 }
70
71 void set_stubs_start_offset(int offset) {
72 _stubs_start_offset = offset;
73 }
74
75 int stubs_start_offset() {
76 return _stubs_start_offset;
77 }
78 };
79
80 class ShenandoahBarrierSetC2 : public BarrierSetC2 {
81
82 static bool clone_needs_barrier(const TypeOopPtr* src_type, bool& is_oop_array);
83
84 static bool can_remove_load_barrier(Node* node);
85
86 static uint8_t refine_load(Node* node, uint8_t bd);
87 static uint8_t refine_store(Node* node, uint8_t bd);
88
89 static bool is_Load(int opcode);
90 static bool is_Store(int opcode);
91 static bool is_LoadStore(int opcode);
92
93 protected:
94 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
95 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
96 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
97 Node* new_val, const Type* val_type) const;
98 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
99 Node* new_val, const Type* value_type) const;
100 virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
101
102 public:
103 static ShenandoahBarrierSetC2* bsc2();
104
105 ShenandoahBarrierSetC2State* state() const;
106
107 // This is the entry-point for the backend to perform accesses through the Access API.
108 virtual void clone(GraphKit* kit, Node* src_base, Node* dst_base, Node* size, bool is_array) const;
109 virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const;
110
111 // These are general helper methods used by C2
112 virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone,
113 bool is_clone_instance, ArrayCopyPhase phase) const;
114
115 // Support for GC barriers emitted during parsing
116 virtual bool expand_barriers(Compile* C, PhaseIterGVN& igvn) const;
117
118 // Support for macro expanded GC barriers
119 virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const;
120 virtual void eliminate_gc_barrier_data(Node* node) const;
121
122 // Allow barrier sets to have shared state that is preserved across a compilation unit.
123 // This could for example comprise macro nodes to be expanded during macro expansion.
124 virtual void* create_barrier_state(Arena* comp_arena) const;
125
126 #ifdef ASSERT
127 virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const;
128 static void verify_gc_barrier_assert(bool cond, const char* msg, uint8_t bd, Node* n);
129 #endif
130
131 int estimate_stub_size() const /* override */;
132 void emit_stubs(CodeBuffer& cb) const /* override */;
133 void late_barrier_analysis() const /* override*/ {
134 compute_liveness_at_stubs();
135 analyze_dominating_barriers();
136 }
137
138 void elide_dominated_barrier(MachNode* mach, MachNode* dominator) const;
139 void analyze_dominating_barriers() const;
140 void strip_extra_data(const Node* node) const;
141 void strip_extra_data(Node_List& accesses) const;
142
143 virtual uint estimated_barrier_size(const Node* node) const;
144
145 static void print_barrier_data(outputStream* os, uint8_t data);
146 };
147
148 class ShenandoahBarrierStubC2 : public BarrierStubC2 {
149 Register _obj;
150 Address const _addr;
151 const bool _do_load;
152 const bool _narrow;
153 const bool _maybe_null;
154 const bool _needs_load_ref_barrier;
155 const bool _needs_load_ref_weak_barrier;
156 const bool _needs_keep_alive_barrier;
157 bool _needs_far_jump;
158
159 static void register_stub(ShenandoahBarrierStubC2* stub);
160
161 int available_gp_registers();
162 bool is_live_register(Register reg);
163 bool is_special_register(Register reg);
164 Register select_temp_register(bool& selected_live, Register skip_reg1 = noreg);
165
166 void keepalive(MacroAssembler& masm, Label* L_done = nullptr);
167 void lrb(MacroAssembler& masm, Label* L_done = nullptr);
168
169 address keepalive_runtime_entry_addr();
170 address lrb_runtime_entry_addr();
171
172 void maybe_far_jump_if_zero(MacroAssembler& masm, Register reg, Label* L_done);
173 void post_init();
174
175 public:
176 ShenandoahBarrierStubC2(const MachNode* node, Register obj, Address addr, bool narrow, bool do_load) :
177 BarrierStubC2(node),
178 _obj(obj),
179 _addr(addr),
180 _do_load(do_load),
181 _narrow(narrow),
182 _maybe_null(maybe_null(node)),
183 _needs_load_ref_barrier(needs_load_ref_barrier(node)),
184 _needs_load_ref_weak_barrier(needs_load_ref_barrier_weak(node)),
185 _needs_keep_alive_barrier(needs_keep_alive_barrier(node)),
186 _needs_far_jump() {
187 assert(!_narrow || is_heap_access(node), "Only heap accesses can be narrow");
188 post_init();
189 }
190
191 static bool is_heap_access(const MachNode* node) {
192 return (node->barrier_data() & ShenandoahBitNative) == 0;
193 }
194 static bool needs_slow_barrier(const MachNode* node) {
195 return needs_load_ref_barrier(node) || needs_keep_alive_barrier(node);
196 }
197 static bool needs_load_ref_barrier(const MachNode* node) {
198 return (node->barrier_data() & (ShenandoahBitStrong | ShenandoahBitWeak | ShenandoahBitPhantom)) != 0;
199 }
200 static bool needs_load_ref_barrier_weak(const MachNode* node) {
201 return (node->barrier_data() & (ShenandoahBitWeak | ShenandoahBitPhantom)) != 0;
202 }
203 static bool needs_keep_alive_barrier(const MachNode* node) {
204 return (node->barrier_data() & ShenandoahBitKeepAlive) != 0;
205 }
206 static bool needs_card_barrier(const MachNode* node) {
207 return (node->barrier_data() & ShenandoahBitCardMark) != 0;
208 }
209 static bool maybe_null(const MachNode* node) {
210 return (node->barrier_data() & ShenandoahBitNotNull) == 0;
211 }
212
213 static ShenandoahBarrierStubC2* create(const MachNode* node, Register obj, Address addr, bool narrow, bool do_load);
214 void emit_code(MacroAssembler& masm);
215
216 void enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp = noreg);
217 };
218 #endif // SHARE_GC_SHENANDOAH_C2_SHENANDOAHBARRIERSETC2_HPP