1 /*
  2  * Copyright (c) 2015, 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_SHENANDOAHSUPPORT_HPP
 26 #define SHARE_GC_SHENANDOAH_C2_SHENANDOAHSUPPORT_HPP
 27 
 28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
 29 #include "memory/allocation.hpp"
 30 #include "opto/addnode.hpp"
 31 #include "opto/graphKit.hpp"
 32 #include "opto/machnode.hpp"
 33 #include "opto/memnode.hpp"
 34 #include "opto/multnode.hpp"
 35 #include "opto/node.hpp"
 36 
 37 class PhaseGVN;
 38 class MemoryGraphFixer;
 39 
 40 class ShenandoahBarrierC2Support : public AllStatic {
 41 private:
 42 #ifdef ASSERT
 43   enum verify_type {
 44     ShenandoahLoad,
 45     ShenandoahStore,
 46     ShenandoahValue,
 47     ShenandoahOopStore,
 48     ShenandoahNone
 49   };
 50 
 51   static bool verify_helper(Node* in, Node_Stack& phis, VectorSet& visited, verify_type t, bool trace, Unique_Node_List& barriers_used);
 52   static void report_verify_failure(const char* msg, Node* n1 = nullptr, Node* n2 = nullptr);
 53 #endif
 54   static Node* dom_mem(Node* mem, Node* ctrl, int alias, Node*& mem_ctrl, PhaseIdealLoop* phase);
 55   static Node* no_branches(Node* c, Node* dom, bool allow_one_proj, PhaseIdealLoop* phase);
 56   static bool is_gc_state_test(Node* iff, int mask);
 57   static bool has_safepoint_between(Node* start, Node* stop, PhaseIdealLoop *phase);
 58   static Node* find_bottom_mem(Node* ctrl, PhaseIdealLoop* phase);
 59   static void follow_barrier_uses(Node* n, Node* ctrl, Unique_Node_List& uses, PhaseIdealLoop* phase);
 60   static void test_null(Node*& ctrl, Node* val, Node*& null_ctrl, PhaseIdealLoop* phase);
 61   static void test_gc_state(Node*& ctrl, Node* raw_mem, Node*& heap_stable_ctrl,
 62                             PhaseIdealLoop* phase, int flags);
 63   static void call_lrb_stub(Node*& ctrl, Node*& val, Node* load_addr,
 64                             DecoratorSet decorators, PhaseIdealLoop* phase);
 65 
 66   static void collect_nodes_above_barrier(Unique_Node_List &nodes_above_barrier, PhaseIdealLoop* phase, Node* ctrl,
 67                                           Node* init_raw_mem);
 68 
 69   static void test_in_cset(Node*& ctrl, Node*& not_cset_ctrl, Node* val, Node* raw_mem, PhaseIdealLoop* phase);
 70   static void move_gc_state_test_out_of_loop(IfNode* iff, PhaseIdealLoop* phase);
 71   static void merge_back_to_back_tests(Node* n, PhaseIdealLoop* phase);
 72   static bool merge_point_safe(Node* region);
 73   static bool identical_backtoback_ifs(Node *n, PhaseIdealLoop* phase);
 74   static void fix_ctrl(Node* barrier, Node* region, const MemoryGraphFixer& fixer, Unique_Node_List& uses, Unique_Node_List& nodes_above_barrier, uint last, PhaseIdealLoop* phase);
 75   static IfNode* find_unswitching_candidate(const IdealLoopTree *loop, PhaseIdealLoop* phase);
 76 
 77   static Node* get_load_addr(PhaseIdealLoop* phase, VectorSet& visited, Node* lrb);
 78 public:
 79   static bool is_dominator(Node* d_c, Node* n_c, Node* d, Node* n, PhaseIdealLoop* phase);
 80   static bool is_dominator_same_ctrl(Node* c, Node* d, Node* n, PhaseIdealLoop* phase);
 81 
 82   static bool is_gc_state_load(Node* n);
 83   static bool is_heap_stable_test(Node* iff);
 84 
 85   static bool expand(Compile* C, PhaseIterGVN& igvn);
 86   static void pin_and_expand(PhaseIdealLoop* phase);
 87   static void optimize_after_expansion(VectorSet& visited, Node_Stack& nstack, Node_List& old_new, PhaseIdealLoop* phase);
 88 
 89   static void push_data_inputs_at_control(PhaseIdealLoop* phase, Node* n, Node* ctrl,
 90                                           Unique_Node_List &wq);
 91   static bool is_anti_dependent_load_at_control(PhaseIdealLoop* phase, Node* maybe_load, Node* store, Node* control);
 92 
 93   static void maybe_push_anti_dependent_loads(PhaseIdealLoop* phase, Node* maybe_store, Node* control, Unique_Node_List &wq);
 94 #ifdef ASSERT
 95   static void verify(RootNode* root);
 96 #endif
 97 };
 98 
 99 class ShenandoahIUBarrierNode : public Node {
100 public:
101   ShenandoahIUBarrierNode(Node* val);
102 
103   const Type *bottom_type() const;
104   const Type* Value(PhaseGVN* phase) const;
105   Node* Identity(PhaseGVN* phase);
106 
107   int Opcode() const;
108 
109 private:
110   enum { Needed, NotNeeded, MaybeNeeded };
111 
112   static int needed(Node* n);
113   static Node* next(Node* n);
114 };
115 
116 class MemoryGraphFixer : public ResourceObj {
117 private:
118   Node_List _memory_nodes;
119   int _alias;
120   PhaseIdealLoop* _phase;
121   bool _include_lsm;
122 
123   void collect_memory_nodes();
124   Node* get_ctrl(Node* n) const;
125   Node* ctrl_or_self(Node* n) const;
126   bool mem_is_valid(Node* m, Node* c) const;
127   MergeMemNode* allocate_merge_mem(Node* mem, Node* rep_proj, Node* rep_ctrl) const;
128   MergeMemNode* clone_merge_mem(Node* u, Node* mem, Node* rep_proj, Node* rep_ctrl, DUIterator& i) const;
129   void fix_memory_uses(Node* mem, Node* replacement, Node* rep_proj, Node* rep_ctrl) const;
130   bool should_process_phi(Node* phi) const;
131   bool has_mem_phi(Node* region) const;
132 
133 public:
134   MemoryGraphFixer(int alias, bool include_lsm, PhaseIdealLoop* phase) :
135     _alias(alias), _phase(phase), _include_lsm(include_lsm) {
136     assert(_alias != Compile::AliasIdxBot, "unsupported");
137     collect_memory_nodes();
138   }
139 
140   Node* find_mem(Node* ctrl, Node* n) const;
141   void fix_mem(Node* ctrl, Node* region, Node* mem, Node* mem_for_ctrl, Node* mem_phi, Unique_Node_List& uses);
142   int alias() const { return _alias; }
143 
144   Node* collect_memory_for_infinite_loop(const Node* in);
145 
146   void record_new_ctrl(Node* ctrl, Node* region, Node* mem, Node* mem_for_ctrl);
147 };
148 
149 class ShenandoahCompareAndSwapPNode : public CompareAndSwapPNode {
150 public:
151   ShenandoahCompareAndSwapPNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord)
152     : CompareAndSwapPNode(c, mem, adr, val, ex, mem_ord) { }
153 
154   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
155     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypePtr::NULL_PTR) {
156       return new CompareAndSwapPNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), order());
157     }
158     return nullptr;
159   }
160 
161   virtual int Opcode() const;
162 };
163 
164 class ShenandoahCompareAndSwapNNode : public CompareAndSwapNNode {
165 public:
166   ShenandoahCompareAndSwapNNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord)
167     : CompareAndSwapNNode(c, mem, adr, val, ex, mem_ord) { }
168 
169   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
170     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypeNarrowOop::NULL_PTR) {
171       return new CompareAndSwapNNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), order());
172     }
173     return nullptr;
174   }
175 
176   virtual int Opcode() const;
177 };
178 
179 class ShenandoahWeakCompareAndSwapPNode : public WeakCompareAndSwapPNode {
180 public:
181   ShenandoahWeakCompareAndSwapPNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord)
182     : WeakCompareAndSwapPNode(c, mem, adr, val, ex, mem_ord) { }
183 
184   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
185     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypePtr::NULL_PTR) {
186       return new WeakCompareAndSwapPNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), order());
187     }
188     return nullptr;
189   }
190 
191   virtual int Opcode() const;
192 };
193 
194 class ShenandoahWeakCompareAndSwapNNode : public WeakCompareAndSwapNNode {
195 public:
196   ShenandoahWeakCompareAndSwapNNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord)
197     : WeakCompareAndSwapNNode(c, mem, adr, val, ex, mem_ord) { }
198 
199   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
200     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypeNarrowOop::NULL_PTR) {
201       return new WeakCompareAndSwapNNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), order());
202     }
203     return nullptr;
204   }
205 
206   virtual int Opcode() const;
207 };
208 
209 class ShenandoahCompareAndExchangePNode : public CompareAndExchangePNode {
210 public:
211   ShenandoahCompareAndExchangePNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord)
212     : CompareAndExchangePNode(c, mem, adr, val, ex, at, t, mem_ord) { }
213 
214   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
215     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypePtr::NULL_PTR) {
216       return new CompareAndExchangePNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), adr_type(), bottom_type(), order());
217     }
218     return nullptr;
219   }
220 
221   virtual int Opcode() const;
222 };
223 
224 class ShenandoahCompareAndExchangeNNode : public CompareAndExchangeNNode {
225 public:
226   ShenandoahCompareAndExchangeNNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord)
227     : CompareAndExchangeNNode(c, mem, adr, val, ex, at, t, mem_ord) { }
228 
229   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape) {
230     if (in(ExpectedIn) != nullptr && phase->type(in(ExpectedIn)) == TypeNarrowOop::NULL_PTR) {
231       return new CompareAndExchangeNNode(in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), in(MemNode::ValueIn), in(ExpectedIn), adr_type(), bottom_type(), order());
232     }
233     return nullptr;
234   }
235 
236   virtual int Opcode() const;
237 };
238 
239 class ShenandoahLoadReferenceBarrierNode : public Node {
240 public:
241   enum {
242     Control,
243     ValueIn
244   };
245 
246 private:
247   DecoratorSet _decorators;
248 
249 public:
250   ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* val, DecoratorSet decorators);
251 
252   DecoratorSet decorators() const;
253   virtual int Opcode() const;
254   virtual const Type* bottom_type() const;
255   virtual const Type* Value(PhaseGVN* phase) const;
256   virtual const class TypePtr *adr_type() const { return TypeOopPtr::BOTTOM; }
257   virtual uint match_edge(uint idx) const {
258     return idx >= ValueIn;
259   }
260   virtual uint ideal_reg() const { return Op_RegP; }
261 
262   virtual Node* Identity(PhaseGVN* phase);
263 
264   virtual uint size_of() const;
265   virtual uint hash() const;
266   virtual bool cmp( const Node &n ) const;
267 
268 private:
269   bool needs_barrier(PhaseGVN* phase, Node* n);
270   bool needs_barrier_impl(PhaseGVN* phase, Node* n, Unique_Node_List &visited);
271 };
272 
273 
274 #endif // SHARE_GC_SHENANDOAH_C2_SHENANDOAHSUPPORT_HPP