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.
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23 */
24
25 #ifndef SHARE_GC_SHARED_C2_BARRIERSETC2_HPP
26 #define SHARE_GC_SHARED_C2_BARRIERSETC2_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/accessDecorators.hpp"
30 #include "opto/loopnode.hpp"
31 #include "opto/memnode.hpp"
32 #include "utilities/globalDefinitions.hpp"
33
34 // This means the access is mismatched. This means the value of an access
35 // is not equivalent to the value pointed to by the address.
36 const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1;
37 // The access may not be aligned to its natural size.
38 const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2;
39 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
40 // but never false positives.
41 const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3;
42 // This denotes that a load has control dependency.
43 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
44 // This denotes that a load that must be pinned.
45 const DecoratorSet C2_PINNED_LOAD = DECORATOR_LAST << 5;
46 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
47 const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6;
48 // This denotes that the access mutates state.
49 const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7;
50 // This denotes that the access reads state.
51 const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8;
52
53 class GraphKit;
54 class IdealKit;
55 class Node;
56 class Type;
57 class TypePtr;
58 class PhaseMacroExpand;
59
60 // This class wraps a node and a type.
61 class C2AccessValue: public StackObj {
62 protected:
63 Node* _node;
64 const Type* _type;
65
66 public:
67 C2AccessValue(Node* node, const Type* type) :
68 _node(node),
69 _type(type) {}
70
71 Node* node() const { return _node; }
72 const Type* type() const { return _type; }
73
74 void set_node(Node* node) { _node = node; }
75 };
76
77 // This class wraps a node and a pointer type.
78 class C2AccessValuePtr: public C2AccessValue {
79
80 public:
81 C2AccessValuePtr(Node* node, const TypePtr* type) :
82 C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}
83
84 const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
85 };
86
87 // This class wraps a bunch of context parameters thare are passed around in the
88 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
89 class C2Access: public StackObj {
90 protected:
91 GraphKit* _kit;
92 DecoratorSet _decorators;
93 BasicType _type;
94 Node* _base;
95 C2AccessValuePtr& _addr;
96 Node* _raw_access;
97
98 void fixup_decorators();
99 void* barrier_set_state() const;
100
101 public:
102 C2Access(GraphKit* kit, DecoratorSet decorators,
103 BasicType type, Node* base, C2AccessValuePtr& addr) :
104 _kit(kit),
105 _decorators(decorators),
106 _type(type),
107 _base(base),
108 _addr(addr),
109 _raw_access(NULL)
110 {
111 fixup_decorators();
112 }
113
114 GraphKit* kit() const { return _kit; }
115 DecoratorSet decorators() const { return _decorators; }
116 Node* base() const { return _base; }
117 C2AccessValuePtr& addr() const { return _addr; }
118 BasicType type() const { return _type; }
119 bool is_oop() const { return _type == T_OBJECT || _type == T_ARRAY; }
120 bool is_raw() const { return (_decorators & AS_RAW) != 0; }
121 Node* raw_access() const { return _raw_access; }
122
123 void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
124 virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
125
126 MemNode::MemOrd mem_node_mo() const;
127 bool needs_cpu_membar() const;
128
129 template <typename T>
130 T barrier_set_state_as() const {
131 return reinterpret_cast<T>(barrier_set_state());
132 }
133 };
134
135 // This class wraps a bunch of context parameters thare are passed around in the
136 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
137 class C2AtomicAccess: public C2Access {
138 Node* _memory;
139 uint _alias_idx;
140 bool _needs_pinning;
141
142 public:
143 C2AtomicAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
144 Node* base, C2AccessValuePtr& addr, uint alias_idx) :
145 C2Access(kit, decorators, type, base, addr),
146 _memory(NULL),
147 _alias_idx(alias_idx),
148 _needs_pinning(true) {}
149
150 // Set the memory node based on the current memory slice.
151 virtual void set_memory();
152
153 Node* memory() const { return _memory; }
154 uint alias_idx() const { return _alias_idx; }
155 bool needs_pinning() const { return _needs_pinning; }
156
157 void set_needs_pinning(bool value) { _needs_pinning = value; }
158 };
159
160 // This is the top-level class for the backend of the Access API in C2.
161 // The top-level class is responsible for performing raw accesses. The
162 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
163 // barriers into the accesses.
164 class BarrierSetC2: public CHeapObj<mtGC> {
165 protected:
166 virtual void resolve_address(C2Access& access) const;
167 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
168 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
169
170 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
171 Node* new_val, const Type* val_type) const;
172 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
173 Node* new_val, const Type* value_type) const;
174 virtual Node* atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;
175 virtual Node* atomic_add_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;
176 void pin_atomic_op(C2AtomicAccess& access) const;
177
178 public:
179 // This is the entry-point for the backend to perform accesses through the Access API.
180 virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
181 virtual Node* load_at(C2Access& access, const Type* val_type) const;
182
183 virtual Node* atomic_cmpxchg_val_at(C2AtomicAccess& access, Node* expected_val,
184 Node* new_val, const Type* val_type) const;
185 virtual Node* atomic_cmpxchg_bool_at(C2AtomicAccess& access, Node* expected_val,
186 Node* new_val, const Type* val_type) const;
187 virtual Node* atomic_xchg_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;
188 virtual Node* atomic_add_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;
189
190 virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const;
191
192 virtual Node* resolve(GraphKit* kit, Node* n, DecoratorSet decorators) const { return n; }
193
194 virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* ctrl, Node* mem, Node* toobig_false, Node* size_in_bytes,
195 Node*& i_o, Node*& needgc_ctrl,
196 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem,
197 intx prefetch_lines) const;
198
199 // These are general helper methods used by C2
200 enum ArrayCopyPhase {
201 Parsing,
202 Optimization,
203 Expansion
204 };
205 virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const { return false; }
206
207 // Support for GC barriers emitted during parsing
208 virtual bool has_load_barriers() const { return false; }
209 virtual bool is_gc_barrier_node(Node* node) const { return false; }
210 virtual Node* step_over_gc_barrier(Node* c) const { return c; }
211
212 // Support for macro expanded GC barriers
213 virtual void register_potential_barrier_node(Node* node) const { }
214 virtual void unregister_potential_barrier_node(Node* node) const { }
215 virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
216 virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {}
217 virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {}
218 virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}
219
220 // Allow barrier sets to have shared state that is preserved across a compilation unit.
221 // This could for example comprise macro nodes to be expanded during macro expansion.
222 virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
223 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
224 // expanded later, then now is the time to do so.
225 virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
226 virtual void verify_gc_barriers(bool post_parse) const {}
227 };
228
229 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP