1 /*
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  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
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 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
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 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/matcher.hpp"
 32 #include "opto/memnode.hpp"
 33 #include "utilities/globalDefinitions.hpp"
 34 
 35 // This means the access is mismatched. This means the value of an access
 36 // is not equivalent to the value pointed to by the address.
 37 const DecoratorSet C2_MISMATCHED             = DECORATOR_LAST << 1;
 38 // The access may not be aligned to its natural size.
 39 const DecoratorSet C2_UNALIGNED              = DECORATOR_LAST << 2;
 40 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
 41 // but never false positives.
 42 const DecoratorSet C2_WEAK_CMPXCHG           = DECORATOR_LAST << 3;
 43 // This denotes that a load has control dependency.
 44 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
 45 // This denotes that a load that must be pinned, but may float above safepoints.
 46 const DecoratorSet C2_UNKNOWN_CONTROL_LOAD   = DECORATOR_LAST << 5;
 47 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
 48 const DecoratorSet C2_UNSAFE_ACCESS          = DECORATOR_LAST << 6;
 49 // This denotes that the access mutates state.
 50 const DecoratorSet C2_WRITE_ACCESS           = DECORATOR_LAST << 7;
 51 // This denotes that the access reads state.
 52 const DecoratorSet C2_READ_ACCESS            = DECORATOR_LAST << 8;
 53 // A nearby allocation?
 54 const DecoratorSet C2_TIGHTLY_COUPLED_ALLOC  = DECORATOR_LAST << 9;
 55 // Loads and stores from an arraycopy being optimized
 56 const DecoratorSet C2_ARRAY_COPY             = DECORATOR_LAST << 10;
 57 // Loads from immutable memory
 58 const DecoratorSet C2_IMMUTABLE_MEMORY       = DECORATOR_LAST << 11;
 59 
 60 class Compile;
 61 class ConnectionGraph;
 62 class GraphKit;
 63 class IdealKit;
 64 class Node;
 65 class PhaseGVN;
 66 class PhaseIdealLoop;
 67 class PhaseMacroExpand;
 68 class Type;
 69 class TypePtr;
 70 class Unique_Node_List;
 71 
 72 // This class wraps a node and a type.
 73 class C2AccessValue: public StackObj {
 74 protected:
 75   Node* _node;
 76   const Type* _type;
 77 
 78 public:
 79   C2AccessValue(Node* node, const Type* type) :
 80     _node(node),
 81     _type(type) {}
 82 
 83   Node* node() const        { return _node; }
 84   const Type* type() const  { return _type; }
 85 
 86   void set_node(Node* node) { _node = node; }
 87 };
 88 
 89 // This class wraps a node and a pointer type.
 90 class C2AccessValuePtr: public C2AccessValue {
 91 
 92 public:
 93   C2AccessValuePtr(Node* node, const TypePtr* type) :
 94     C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}
 95 
 96   const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
 97 };
 98 
 99 // This class wraps a bunch of context parameters thare are passed around in the
100 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
101 class C2Access: public StackObj {
102 protected:
103   DecoratorSet      _decorators;
104   BasicType         _type;
105   Node*             _base;
106   C2AccessValuePtr& _addr;
107   Node*             _raw_access;
108   uint8_t           _barrier_data;
109 
110   void fixup_decorators();
111 
112 public:
113   C2Access(DecoratorSet decorators,
114            BasicType type, Node* base, C2AccessValuePtr& addr) :
115     _decorators(decorators),
116     _type(type),
117     _base(base),
118     _addr(addr),
119     _raw_access(NULL),
120     _barrier_data(0)
121   {}
122 
123   DecoratorSet decorators() const { return _decorators; }
124   Node* base() const              { return _base; }
125   C2AccessValuePtr& addr() const  { return _addr; }
126   BasicType type() const          { return _type; }
127   bool is_oop() const             { return is_reference_type(_type); }
128   bool is_raw() const             { return (_decorators & AS_RAW) != 0; }
129   Node* raw_access() const        { return _raw_access; }
130 
131   uint8_t barrier_data() const        { return _barrier_data; }
132   void set_barrier_data(uint8_t data) { _barrier_data = data; }
133 
134   void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
135   virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
136 
137   MemNode::MemOrd mem_node_mo() const;
138   bool needs_cpu_membar() const;
139 
140   virtual PhaseGVN& gvn() const = 0;
141   virtual bool is_parse_access() const { return false; }
142   virtual bool is_opt_access() const { return false; }
143 };
144 
145 // C2Access for parse time calls to the BarrierSetC2 backend.
146 class C2ParseAccess: public C2Access {
147 protected:
148   GraphKit*         _kit;
149   Node* _ctl;
150 
151   void* barrier_set_state() const;
152 
153 public:
154   C2ParseAccess(GraphKit* kit, DecoratorSet decorators,
155                 BasicType type, Node* base, C2AccessValuePtr& addr,
156                 Node* ctl = NULL) :
157     C2Access(decorators, type, base, addr),
158     _kit(kit),
159     _ctl(ctl) {
160     fixup_decorators();
161   }
162 
163   GraphKit* kit() const           { return _kit; }
164   Node* control() const;
165 
166   virtual PhaseGVN& gvn() const;
167   virtual bool is_parse_access() const { return true; }
168 };
169 
170 // This class wraps a bunch of context parameters thare are passed around in the
171 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
172 class C2AtomicParseAccess: public C2ParseAccess {
173   Node* _memory;
174   uint  _alias_idx;
175   bool  _needs_pinning;
176 
177 public:
178   C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
179                  Node* base, C2AccessValuePtr& addr, uint alias_idx) :
180     C2ParseAccess(kit, decorators, type, base, addr),
181     _memory(NULL),
182     _alias_idx(alias_idx),
183     _needs_pinning(true) {}
184 
185   // Set the memory node based on the current memory slice.
186   virtual void set_memory();
187 
188   Node* memory() const       { return _memory; }
189   uint alias_idx() const     { return _alias_idx; }
190   bool needs_pinning() const { return _needs_pinning; }
191 };
192 
193 // C2Access for optimization time calls to the BarrierSetC2 backend.
194 class C2OptAccess: public C2Access {
195   PhaseGVN& _gvn;
196   MergeMemNode* _mem;
197   Node* _ctl;
198 
199 public:
200   C2OptAccess(PhaseGVN& gvn, Node* ctl, MergeMemNode* mem, DecoratorSet decorators,
201               BasicType type, Node* base, C2AccessValuePtr& addr) :
202     C2Access(decorators, type, base, addr),
203     _gvn(gvn), _mem(mem), _ctl(ctl) {
204     fixup_decorators();
205   }
206 
207   MergeMemNode* mem() const { return _mem; }
208   Node* ctl() const { return _ctl; }
209 
210   virtual PhaseGVN& gvn() const { return _gvn; }
211   virtual bool is_opt_access() const { return true; }
212 };
213 
214 
215 // This is the top-level class for the backend of the Access API in C2.
216 // The top-level class is responsible for performing raw accesses. The
217 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
218 // barriers into the accesses.
219 class BarrierSetC2: public CHeapObj<mtGC> {
220 protected:
221   virtual void resolve_address(C2Access& access) const;
222   virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
223   virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
224 
225   virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
226                                                Node* new_val, const Type* val_type) const;
227   virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
228                                                 Node* new_val, const Type* value_type) const;
229   virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
230   virtual Node* atomic_add_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
231   void pin_atomic_op(C2AtomicParseAccess& access) const;
232 
233 public:
234   // This is the entry-point for the backend to perform accesses through the Access API.
235   virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
236   virtual Node* load_at(C2Access& access, const Type* val_type) const;
237 
238   virtual Node* atomic_cmpxchg_val_at(C2AtomicParseAccess& access, Node* expected_val,
239                                       Node* new_val, const Type* val_type) const;
240   virtual Node* atomic_cmpxchg_bool_at(C2AtomicParseAccess& access, Node* expected_val,
241                                        Node* new_val, const Type* val_type) const;
242   virtual Node* atomic_xchg_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
243   virtual Node* atomic_add_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
244 
245   virtual void clone(GraphKit* kit, Node* src_base, Node* dst_base, Node* size, bool is_array) const;
246 
247   virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* mem, Node* toobig_false, Node* size_in_bytes,
248                              Node*& i_o, Node*& needgc_ctrl,
249                              Node*& fast_oop_ctrl, Node*& fast_oop_rawmem,
250                              intx prefetch_lines) const;
251 
252   virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; }
253 
254   // These are general helper methods used by C2
255   enum ArrayCopyPhase {
256     Parsing,
257     Optimization,
258     Expansion
259   };
260 
261   virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const { return false; }
262   virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const;
263 
264   // Support for GC barriers emitted during parsing
265   virtual bool has_load_barrier_nodes() const { return false; }
266   virtual bool is_gc_barrier_node(Node* node) const { return false; }
267   virtual Node* step_over_gc_barrier(Node* c) const { return c; }
268 
269   // Support for macro expanded GC barriers
270   virtual void register_potential_barrier_node(Node* node) const { }
271   virtual void unregister_potential_barrier_node(Node* node) const { }
272   virtual void eliminate_gc_barrier(PhaseIterGVN* igvn, Node* node) const { }
273   virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {}
274   virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {}
275 
276   // Allow barrier sets to have shared state that is preserved across a compilation unit.
277   // This could for example comprise macro nodes to be expanded during macro expansion.
278   virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
279   // If the BarrierSetC2 state has barrier nodes in its compilation
280   // unit state to be expanded later, then now is the time to do so.
281   virtual bool expand_barriers(Compile* C, PhaseIterGVN& igvn) const { return false; }
282   virtual bool optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const { return false; }
283   virtual bool strip_mined_loops_expanded(LoopOptsMode mode) const { return false; }
284   virtual bool is_gc_specific_loop_opts_pass(LoopOptsMode mode) const { return false; }
285 
286   enum CompilePhase {
287     BeforeOptimize,
288     BeforeMacroExpand,
289     BeforeCodeGen
290   };
291 
292 #ifdef ASSERT
293   virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const {}
294 #endif
295 
296   virtual bool final_graph_reshaping(Compile* compile, Node* n, uint opcode) const { return false; }
297 
298   virtual bool escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const { return false; }
299   virtual bool escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const { return false; }
300   virtual bool escape_has_out_with_unsafe_object(Node* n) const { return false; }
301 
302   virtual bool matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const { return false; };
303   virtual bool matcher_is_store_load_barrier(Node* x, uint xop) const { return false; }
304 
305   virtual void late_barrier_analysis() const { }
306   virtual int estimate_stub_size() const { return 0; }
307   virtual void emit_stubs(CodeBuffer& cb) const { }
308 
309   static int arraycopy_payload_base_offset(bool is_array);
310 };
311 
312 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP