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/memnode.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 // This means the access is mismatched. This means the value of an access
34 // is not equivalent to the value pointed to by the address.
35 const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1;
36 // The access may not be aligned to its natural size.
37 const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2;
38 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
39 // but never false positives.
40 const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3;
41 // This denotes that a load has control dependency.
42 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
43 // This denotes that a load that must be pinned.
44 const DecoratorSet C2_PINNED_LOAD = DECORATOR_LAST << 5;
45 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
46 const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6;
47 // This denotes that the access mutates state.
48 const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7;
49 // This denotes that the access reads state.
50 const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8;
51
52 class GraphKit;
53 class IdealKit;
54 class Node;
55 class Type;
56 class TypePtr;
57 class PhaseMacroExpand;
58
59 // This class wraps a node and a type.
60 class C2AccessValue: public StackObj {
61 protected:
62 Node* _node;
63 const Type* _type;
64
65 public:
66 C2AccessValue(Node* node, const Type* type) :
67 _node(node),
68 _type(type) {}
69
70 Node* node() const { return _node; }
71 const Type* type() const { return _type; }
72
73 void set_node(Node* node) { _node = node; }
74 };
75
76 // This class wraps a node and a pointer type.
77 class C2AccessValuePtr: public C2AccessValue {
78 int _alias_idx;
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 int alias_idx() const { return _alias_idx; }
86 };
87
88 // This class wraps a bunch of context parameters thare are passed around in the
89 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
90 class C2Access: public StackObj {
91 protected:
92 GraphKit* _kit;
93 DecoratorSet _decorators;
94 BasicType _type;
95 Node* _base;
96 C2AccessValuePtr& _addr;
97 Node* _raw_access;
98
99 void fixup_decorators();
100 void* barrier_set_state() const;
101
102 public:
103 C2Access(GraphKit* kit, DecoratorSet decorators,
104 BasicType type, Node* base, C2AccessValuePtr& addr) :
105 _kit(kit),
106 _decorators(decorators),
107 _type(type),
108 _base(base),
109 _addr(addr),
110 _raw_access(NULL)
111 {
112 fixup_decorators();
113 }
114
115 GraphKit* kit() const { return _kit; }
116 DecoratorSet decorators() const { return _decorators; }
117 Node* base() const { return _base; }
118 C2AccessValuePtr& addr() const { return _addr; }
119 BasicType type() const { return _type; }
120 bool is_oop() const { return _type == T_OBJECT || _type == T_ARRAY; }
121 bool is_raw() const { return (_decorators & AS_RAW) != 0; }
122 Node* raw_access() const { return _raw_access; }
123
124 void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
125 virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
126
127 MemNode::MemOrd mem_node_mo() const;
128 bool needs_cpu_membar() const;
129
130 template <typename T>
131 T barrier_set_state_as() const {
132 return reinterpret_cast<T>(barrier_set_state());
133 }
134 };
135
136 // This class wraps a bunch of context parameters thare are passed around in the
137 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
138 class C2AtomicAccess: public C2Access {
139 Node* _memory;
140 uint _alias_idx;
141 bool _needs_pinning;
142
143 public:
144 C2AtomicAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
145 Node* base, C2AccessValuePtr& addr, uint alias_idx) :
146 C2Access(kit, decorators, type, base, addr),
147 _memory(NULL),
148 _alias_idx(alias_idx),
149 _needs_pinning(true) {}
150
151 // Set the memory node based on the current memory slice.
152 virtual void set_memory();
153
154 Node* memory() const { return _memory; }
155 uint alias_idx() const { return _alias_idx; }
156 bool needs_pinning() const { return _needs_pinning; }
157
158 void set_needs_pinning(bool value) { _needs_pinning = value; }
159 };
160
161 // This is the top-level class for the backend of the Access API in C2.
162 // The top-level class is responsible for performing raw accesses. The
163 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
164 // barriers into the accesses.
165 class BarrierSetC2: public CHeapObj<mtGC> {
166 protected:
167 virtual void resolve_address(C2Access& access) const;
168 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
169 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
170
171 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
172 Node* new_val, const Type* val_type) const;
173 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
174 Node* new_val, const Type* value_type) const;
175 virtual Node* atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;
176 virtual Node* atomic_add_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) 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 // These are general helper methods used by C2
193 virtual bool is_gc_barrier_node(Node* node) const { return false; }
194 virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
195 virtual bool array_copy_requires_gc_barriers(BasicType type) const { return false; }
196 virtual Node* step_over_gc_barrier(Node* c) const { return c; }
197
198 virtual void loop_optimize_gc_barrier(Node* node) const { }
199
200 // Allow barrier sets to have shared state that is preserved across a compilation unit.
201 // This could for example comprise macro nodes to be expanded during macro expansion.
202 virtual void* create_barrier_state() const { return NULL; }
203 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
204 // expanded later, then now is the time to do so.
205 virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
206 };
207
208 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP