1 /*
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  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
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  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  *
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 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 24 
 25 #ifndef SHARE_OPTO_CFGNODE_HPP
 26 #define SHARE_OPTO_CFGNODE_HPP
 27 
 28 #include "opto/multnode.hpp"
 29 #include "opto/node.hpp"
 30 #include "opto/opcodes.hpp"
 31 #include "opto/type.hpp"
 32 
 33 // Portions of code courtesy of Clifford Click
 34 
 35 // Optimization - Graph Style
 36 
 37 class Matcher;
 38 class Node;
 39 class   RegionNode;
 40 class   TypeNode;
 41 class     PhiNode;
 42 class   GotoNode;
 43 class   MultiNode;
 44 class     MultiBranchNode;
 45 class       IfNode;
 46 class       PCTableNode;
 47 class         JumpNode;
 48 class         CatchNode;
 49 class       NeverBranchNode;
 50 class     BlackholeNode;
 51 class   ProjNode;
 52 class     CProjNode;
 53 class       IfTrueNode;
 54 class       IfFalseNode;
 55 class       CatchProjNode;
 56 class     JProjNode;
 57 class       JumpProjNode;
 58 class     SCMemProjNode;
 59 class PhaseIdealLoop;
 60 
 61 // The success projection of a Parse Predicate is always an IfTrueNode and the uncommon projection an IfFalseNode
 62 typedef IfTrueNode ParsePredicateSuccessProj;
 63 typedef IfFalseNode ParsePredicateUncommonProj;
 64 
 65 //------------------------------RegionNode-------------------------------------
 66 // The class of RegionNodes, which can be mapped to basic blocks in the
 67 // program.  Their inputs point to Control sources.  PhiNodes (described
 68 // below) have an input point to a RegionNode.  Merged data inputs to PhiNodes
 69 // correspond 1-to-1 with RegionNode inputs.  The zero input of a PhiNode is
 70 // the RegionNode, and the zero input of the RegionNode is itself.
 71 class RegionNode : public Node {
 72 public:
 73   enum LoopStatus {
 74     // No guarantee: the region may be an irreducible loop entry, thus we have to
 75     // be careful when removing entry control to it.
 76     MaybeIrreducibleEntry,
 77     // Limited guarantee: this region may be (nested) inside an irreducible loop,
 78     // but it will never be an irreducible loop entry.
 79     NeverIrreducibleEntry,
 80     // Strong guarantee: this region is not (nested) inside an irreducible loop.
 81     Reducible,
 82   };
 83 
 84 private:
 85   bool _is_unreachable_region;
 86   LoopStatus _loop_status;
 87 
 88   bool is_possible_unsafe_loop(const PhaseGVN* phase) const;
 89   bool is_unreachable_from_root(const PhaseGVN* phase) const;
 90 public:
 91   // Node layout (parallels PhiNode):
 92   enum { Region,                // Generally points to self.
 93          Control                // Control arcs are [1..len)
 94   };
 95 
 96   RegionNode(uint required)
 97     : Node(required),
 98       _is_unreachable_region(false),
 99       _loop_status(LoopStatus::NeverIrreducibleEntry)
100   {
101     init_class_id(Class_Region);
102     init_req(0, this);
103   }
104 
105   Node* is_copy() const {
106     const Node* r = _in[Region];
107     if (r == nullptr)
108       return nonnull_req();
109     return nullptr;  // not a copy!
110   }
111   PhiNode* has_phi() const;        // returns an arbitrary phi user, or null
112   PhiNode* has_unique_phi() const; // returns the unique phi user, or null
113   // Is this region node unreachable from root?
114   bool is_unreachable_region(const PhaseGVN* phase);
115 #ifdef ASSERT
116   bool is_in_infinite_subgraph();
117   static bool are_all_nodes_in_infinite_subgraph(Unique_Node_List& worklist);
118 #endif //ASSERT
119   LoopStatus loop_status() const { return _loop_status; };
120   void set_loop_status(LoopStatus status);
121   DEBUG_ONLY(void verify_can_be_irreducible_entry() const;)
122 
123   virtual int Opcode() const;
124   virtual uint size_of() const { return sizeof(*this); }
125   virtual bool pinned() const { return (const Node*)in(0) == this; }
126   virtual bool is_CFG() const { return true; }
127   virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
128   virtual bool depends_only_on_test() const { return false; }
129   virtual const Type* bottom_type() const { return Type::CONTROL; }
130   virtual const Type* Value(PhaseGVN* phase) const;
131   virtual Node* Identity(PhaseGVN* phase);
132   virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
133   void remove_unreachable_subgraph(PhaseIterGVN* igvn);
134   virtual const RegMask &out_RegMask() const;
135   bool optimize_trichotomy(PhaseIterGVN* igvn);
136   NOT_PRODUCT(virtual void dump_spec(outputStream* st) const;)
137 };
138 
139 //------------------------------JProjNode--------------------------------------
140 // jump projection for node that produces multiple control-flow paths
141 class JProjNode : public ProjNode {
142  public:
143   JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}
144   virtual int Opcode() const;
145   virtual bool  is_CFG() const { return true; }
146   virtual uint  hash() const { return NO_HASH; }  // CFG nodes do not hash
147   virtual const Node* is_block_proj() const { return in(0); }
148   virtual const RegMask& out_RegMask() const;
149   virtual uint  ideal_reg() const { return 0; }
150 };
151 
152 //------------------------------PhiNode----------------------------------------
153 // PhiNodes merge values from different Control paths.  Slot 0 points to the
154 // controlling RegionNode.  Other slots map 1-for-1 with incoming control flow
155 // paths to the RegionNode.
156 class PhiNode : public TypeNode {
157   friend class PhaseRenumberLive;
158 
159   const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.
160   // The following fields are only used for data PhiNodes to indicate
161   // that the PhiNode represents the value of a known instance field.
162         int _inst_mem_id; // Instance memory id (node index of the memory Phi)
163         int _inst_id;     // Instance id of the memory slice.
164   const int _inst_index;  // Alias index of the instance memory slice.
165   // Array elements references have the same alias_idx but different offset.
166   const int _inst_offset; // Offset of the instance memory slice.
167   // Size is bigger to hold the _adr_type field.
168   virtual uint hash() const;    // Check the type
169   virtual bool cmp( const Node &n ) const;
170   virtual uint size_of() const { return sizeof(*this); }
171 
172   // Determine if CMoveNode::is_cmove_id can be used at this join point.
173   Node* is_cmove_id(PhaseTransform* phase, int true_path);
174   bool wait_for_region_igvn(PhaseGVN* phase);
175   bool is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase);
176 
177   static Node* clone_through_phi(Node* root_phi, const Type* t, uint c, PhaseIterGVN* igvn);
178   static Node* merge_through_phi(Node* root_phi, PhaseIterGVN* igvn);
179 
180   bool must_wait_for_region_in_irreducible_loop(PhaseGVN* phase) const;
181 
182 public:
183   // Node layout (parallels RegionNode):
184   enum { Region,                // Control input is the Phi's region.
185          Input                  // Input values are [1..len)
186   };
187 
188   PhiNode( Node *r, const Type *t, const TypePtr* at = nullptr,
189            const int imid = -1,
190            const int iid = TypeOopPtr::InstanceTop,
191            const int iidx = Compile::AliasIdxTop,
192            const int ioffs = Type::OffsetTop )
193     : TypeNode(t,r->req()),
194       _adr_type(at),
195       _inst_mem_id(imid),
196       _inst_id(iid),
197       _inst_index(iidx),
198       _inst_offset(ioffs)
199   {
200     init_class_id(Class_Phi);
201     init_req(0, r);
202     verify_adr_type();
203   }
204   // create a new phi with in edges matching r and set (initially) to x
205   static PhiNode* make( Node* r, Node* x );
206   // extra type arguments override the new phi's bottom_type and adr_type
207   static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = nullptr );
208   // create a new phi with narrowed memory type
209   PhiNode* slice_memory(const TypePtr* adr_type) const;
210   PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;
211   // like make(r, x), but does not initialize the in edges to x
212   static PhiNode* make_blank( Node* r, Node* x );
213 
214   // Accessors
215   RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; }
216 
217   bool is_tripcount(BasicType bt) const;
218 
219   // Determine a unique non-trivial input, if any.
220   // Ignore casts if it helps.  Return null on failure.
221   Node* unique_input(PhaseTransform *phase, bool uncast);
222   Node* unique_input(PhaseTransform *phase) {
223     Node* uin = unique_input(phase, false);
224     if (uin == nullptr) {
225       uin = unique_input(phase, true);
226     }
227     return uin;
228   }
229 
230   // Check for a simple dead loop.
231   enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
232   LoopSafety simple_data_loop_check(Node *in) const;
233   // Is it unsafe data loop? It becomes a dead loop if this phi node removed.
234   bool is_unsafe_data_reference(Node *in) const;
235   int  is_diamond_phi(bool check_control_only = false) const;
236   virtual int Opcode() const;
237   virtual bool pinned() const { return in(0) != 0; }
238   virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; }
239 
240   void  set_inst_mem_id(int inst_mem_id) { _inst_mem_id = inst_mem_id; }
241   const int inst_mem_id() const { return _inst_mem_id; }
242   const int inst_id()     const { return _inst_id; }
243   const int inst_index()  const { return _inst_index; }
244   const int inst_offset() const { return _inst_offset; }
245   bool is_same_inst_field(const Type* tp, int mem_id, int id, int index, int offset) {
246     return type()->basic_type() == tp->basic_type() &&
247            inst_mem_id() == mem_id &&
248            inst_id()     == id     &&
249            inst_index()  == index  &&
250            inst_offset() == offset &&
251            type()->higher_equal(tp);
252   }
253   Node* try_clean_mem_phi(PhaseGVN *phase);
254 
255   InlineTypeNode* push_inline_types_through(PhaseGVN* phase, bool can_reshape, ciInlineKlass* vk, bool is_init);
256 
257   virtual const Type* Value(PhaseGVN* phase) const;
258   virtual Node* Identity(PhaseGVN* phase);
259   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
260   virtual const RegMask &out_RegMask() const;
261   virtual const RegMask &in_RegMask(uint) const;
262 #ifndef PRODUCT
263   virtual void dump_spec(outputStream *st) const;
264 #endif
265 #ifdef ASSERT
266   void verify_adr_type(VectorSet& visited, const TypePtr* at) const;
267   void verify_adr_type(bool recursive = false) const;
268 #else //ASSERT
269   void verify_adr_type(bool recursive = false) const {}
270 #endif //ASSERT
271 };
272 
273 //------------------------------GotoNode---------------------------------------
274 // GotoNodes perform direct branches.
275 class GotoNode : public Node {
276 public:
277   GotoNode( Node *control ) : Node(control) {}
278   virtual int Opcode() const;
279   virtual bool pinned() const { return true; }
280   virtual bool  is_CFG() const { return true; }
281   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
282   virtual const Node *is_block_proj() const { return this; }
283   virtual bool depends_only_on_test() const { return false; }
284   virtual const Type *bottom_type() const { return Type::CONTROL; }
285   virtual const Type* Value(PhaseGVN* phase) const;
286   virtual Node* Identity(PhaseGVN* phase);
287   virtual const RegMask &out_RegMask() const;
288 };
289 
290 //------------------------------CProjNode--------------------------------------
291 // control projection for node that produces multiple control-flow paths
292 class CProjNode : public ProjNode {
293 public:
294   CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}
295   virtual int Opcode() const;
296   virtual bool  is_CFG() const { return true; }
297   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
298   virtual const Node *is_block_proj() const { return in(0); }
299   virtual const RegMask &out_RegMask() const;
300   virtual uint ideal_reg() const { return 0; }
301 };
302 
303 //---------------------------MultiBranchNode-----------------------------------
304 // This class defines a MultiBranchNode, a MultiNode which yields multiple
305 // control values. These are distinguished from other types of MultiNodes
306 // which yield multiple values, but control is always and only projection #0.
307 class MultiBranchNode : public MultiNode {
308 public:
309   MultiBranchNode( uint required ) : MultiNode(required) {
310     init_class_id(Class_MultiBranch);
311   }
312   // returns required number of users to be well formed.
313   virtual int required_outcnt() const = 0;
314 };
315 
316 //------------------------------IfNode-----------------------------------------
317 // Output selected Control, based on a boolean test
318 class IfNode : public MultiBranchNode {
319   // Size is bigger to hold the probability field.  However, _prob does not
320   // change the semantics so it does not appear in the hash & cmp functions.
321   virtual uint size_of() const { return sizeof(*this); }
322 
323 private:
324   // Helper methods for fold_compares
325   bool cmpi_folds(PhaseIterGVN* igvn, bool fold_ne = false);
326   bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);
327   bool has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail);
328   bool has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn);
329   Node* merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
330   static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);
331   bool is_cmp_with_loadrange(ProjNode* proj);
332   bool is_null_check(ProjNode* proj, PhaseIterGVN* igvn);
333   bool is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn);
334   void reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn);
335   ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call) const;
336   bool fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
337   static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);
338 
339 protected:
340   ProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r);
341   Node* Ideal_common(PhaseGVN *phase, bool can_reshape);
342   Node* search_identical(int dist);
343 
344   Node* simple_subsuming(PhaseIterGVN* igvn);
345 
346 public:
347 
348   // Degrees of branch prediction probability by order of magnitude:
349   // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.
350   // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)
351 #define PROB_UNLIKELY_MAG(N)    (1e- ## N ## f)
352 #define PROB_LIKELY_MAG(N)      (1.0f-PROB_UNLIKELY_MAG(N))
353 
354   // Maximum and minimum branch prediction probabilties
355   // 1 in 1,000,000 (magnitude 6)
356   //
357   // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX
358   // they are used to distinguish different situations:
359   //
360   // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to
361   // very likely (unlikely) but with a concrete possibility of a rare
362   // contrary case.  These constants would be used for pinning
363   // measurements, and as measures for assertions that have high
364   // confidence, but some evidence of occasional failure.
365   //
366   // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which
367   // there is no evidence at all that the contrary case has ever occurred.
368 
369 #define PROB_NEVER              PROB_UNLIKELY_MAG(6)
370 #define PROB_ALWAYS             PROB_LIKELY_MAG(6)
371 
372 #define PROB_MIN                PROB_UNLIKELY_MAG(6)
373 #define PROB_MAX                PROB_LIKELY_MAG(6)
374 
375   // Static branch prediction probabilities
376   // 1 in 10 (magnitude 1)
377 #define PROB_STATIC_INFREQUENT  PROB_UNLIKELY_MAG(1)
378 #define PROB_STATIC_FREQUENT    PROB_LIKELY_MAG(1)
379 
380   // Fair probability 50/50
381 #define PROB_FAIR               (0.5f)
382 
383   // Unknown probability sentinel
384 #define PROB_UNKNOWN            (-1.0f)
385 
386   // Probability "constructors", to distinguish as a probability any manifest
387   // constant without a names
388 #define PROB_LIKELY(x)          ((float) (x))
389 #define PROB_UNLIKELY(x)        (1.0f - (float)(x))
390 
391   // Other probabilities in use, but without a unique name, are documented
392   // here for lack of a better place:
393   //
394   // 1 in 1000 probabilities (magnitude 3):
395   //     threshold for converting to conditional move
396   //     likelihood of null check failure if a null HAS been seen before
397   //     likelihood of slow path taken in library calls
398   //
399   // 1 in 10,000 probabilities (magnitude 4):
400   //     threshold for making an uncommon trap probability more extreme
401   //     threshold for for making a null check implicit
402   //     likelihood of needing a gc if eden top moves during an allocation
403   //     likelihood of a predicted call failure
404   //
405   // 1 in 100,000 probabilities (magnitude 5):
406   //     threshold for ignoring counts when estimating path frequency
407   //     likelihood of FP clipping failure
408   //     likelihood of catching an exception from a try block
409   //     likelihood of null check failure if a null has NOT been seen before
410   //
411   // Magic manifest probabilities such as 0.83, 0.7, ... can be found in
412   // gen_subtype_check() and catch_inline_exceptions().
413 
414   float _prob;                  // Probability of true path being taken.
415   float _fcnt;                  // Frequency counter
416   IfNode( Node *control, Node *b, float p, float fcnt )
417     : MultiBranchNode(2), _prob(p), _fcnt(fcnt) {
418     init_class_id(Class_If);
419     init_req(0,control);
420     init_req(1,b);
421   }
422   virtual int Opcode() const;
423   virtual bool pinned() const { return true; }
424   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
425   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
426   virtual const Type* Value(PhaseGVN* phase) const;
427   virtual int required_outcnt() const { return 2; }
428   virtual const RegMask &out_RegMask() const;
429   Node* fold_compares(PhaseIterGVN* phase);
430   static Node* up_one_dom(Node* curr, bool linear_only = false);
431   Node* dominated_by(Node* prev_dom, PhaseIterGVN* igvn);
432 
433   // Takes the type of val and filters it through the test represented
434   // by if_proj and returns a more refined type if one is produced.
435   // Returns null is it couldn't improve the type.
436   static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);
437 
438   bool is_flat_array_check(PhaseTransform* phase, Node** array = NULL);
439 
440 #ifndef PRODUCT
441   virtual void dump_spec(outputStream *st) const;
442 #endif
443 };
444 
445 class RangeCheckNode : public IfNode {
446 private:
447   int is_range_check(Node* &range, Node* &index, jint &offset);
448 
449 public:
450   RangeCheckNode(Node* control, Node *b, float p, float fcnt)
451     : IfNode(control, b, p, fcnt) {
452     init_class_id(Class_RangeCheck);
453   }
454 
455   virtual int Opcode() const;
456   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
457 };
458 
459 class IfProjNode : public CProjNode {
460 public:
461   IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
462   virtual Node* Identity(PhaseGVN* phase);
463 
464 protected:
465   // Type of If input when this branch is always taken
466   virtual bool always_taken(const TypeTuple* t) const = 0;
467 };
468 
469 class IfTrueNode : public IfProjNode {
470 public:
471   IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
472     init_class_id(Class_IfTrue);
473   }
474   virtual int Opcode() const;
475 
476 protected:
477   virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
478 };
479 
480 class IfFalseNode : public IfProjNode {
481 public:
482   IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
483     init_class_id(Class_IfFalse);
484   }
485   virtual int Opcode() const;
486 
487 protected:
488   virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
489 };
490 
491 
492 //------------------------------PCTableNode------------------------------------
493 // Build an indirect branch table.  Given a control and a table index,
494 // control is passed to the Projection matching the table index.  Used to
495 // implement switch statements and exception-handling capabilities.
496 // Undefined behavior if passed-in index is not inside the table.
497 class PCTableNode : public MultiBranchNode {
498   virtual uint hash() const;    // Target count; table size
499   virtual bool cmp( const Node &n ) const;
500   virtual uint size_of() const { return sizeof(*this); }
501 
502 public:
503   const uint _size;             // Number of targets
504 
505   PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
506     init_class_id(Class_PCTable);
507     init_req(0, ctrl);
508     init_req(1, idx);
509   }
510   virtual int Opcode() const;
511   virtual const Type* Value(PhaseGVN* phase) const;
512   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
513   virtual const Type *bottom_type() const;
514   virtual bool pinned() const { return true; }
515   virtual int required_outcnt() const { return _size; }
516 };
517 
518 //------------------------------JumpNode---------------------------------------
519 // Indirect branch.  Uses PCTable above to implement a switch statement.
520 // It emits as a table load and local branch.
521 class JumpNode : public PCTableNode {
522   virtual uint size_of() const { return sizeof(*this); }
523 public:
524   float* _probs; // probability of each projection
525   float _fcnt;   // total number of times this Jump was executed
526   JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
527     : PCTableNode(control, switch_val, size),
528       _probs(probs), _fcnt(cnt) {
529     init_class_id(Class_Jump);
530   }
531   virtual int   Opcode() const;
532   virtual const RegMask& out_RegMask() const;
533   virtual const Node* is_block_proj() const { return this; }
534 };
535 
536 class JumpProjNode : public JProjNode {
537   virtual uint hash() const;
538   virtual bool cmp( const Node &n ) const;
539   virtual uint size_of() const { return sizeof(*this); }
540 
541  private:
542   const int  _dest_bci;
543   const uint _proj_no;
544   const int  _switch_val;
545  public:
546   JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
547     : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
548     init_class_id(Class_JumpProj);
549   }
550 
551   virtual int Opcode() const;
552   virtual const Type* bottom_type() const { return Type::CONTROL; }
553   int  dest_bci()    const { return _dest_bci; }
554   int  switch_val()  const { return _switch_val; }
555   uint proj_no()     const { return _proj_no; }
556 #ifndef PRODUCT
557   virtual void dump_spec(outputStream *st) const;
558   virtual void dump_compact_spec(outputStream *st) const;
559 #endif
560 };
561 
562 //------------------------------CatchNode--------------------------------------
563 // Helper node to fork exceptions.  "Catch" catches any exceptions thrown by
564 // a just-prior call.  Looks like a PCTableNode but emits no code - just the
565 // table.  The table lookup and branch is implemented by RethrowNode.
566 class CatchNode : public PCTableNode {
567 public:
568   CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
569     init_class_id(Class_Catch);
570   }
571   virtual int Opcode() const;
572   virtual const Type* Value(PhaseGVN* phase) const;
573 };
574 
575 // CatchProjNode controls which exception handler is targeted after a call.
576 // It is passed in the bci of the target handler, or no_handler_bci in case
577 // the projection doesn't lead to an exception handler.
578 class CatchProjNode : public CProjNode {
579   virtual uint hash() const;
580   virtual bool cmp( const Node &n ) const;
581   virtual uint size_of() const { return sizeof(*this); }
582 
583 private:
584   const int _handler_bci;
585 
586 public:
587   enum {
588     fall_through_index =  0,      // the fall through projection index
589     catch_all_index    =  1,      // the projection index for catch-alls
590     no_handler_bci     = -1       // the bci for fall through or catch-all projs
591   };
592 
593   CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
594     : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
595     init_class_id(Class_CatchProj);
596     assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
597   }
598 
599   virtual int Opcode() const;
600   virtual Node* Identity(PhaseGVN* phase);
601   virtual const Type *bottom_type() const { return Type::CONTROL; }
602   int  handler_bci() const        { return _handler_bci; }
603   bool is_handler_proj() const    { return _handler_bci >= 0; }
604 #ifndef PRODUCT
605   virtual void dump_spec(outputStream *st) const;
606 #endif
607 };
608 
609 
610 //---------------------------------CreateExNode--------------------------------
611 // Helper node to create the exception coming back from a call
612 class CreateExNode : public TypeNode {
613 public:
614   CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
615     init_req(0, control);
616     init_req(1, i_o);
617   }
618   virtual int Opcode() const;
619   virtual Node* Identity(PhaseGVN* phase);
620   virtual bool pinned() const { return true; }
621   uint match_edge(uint idx) const { return 0; }
622   virtual uint ideal_reg() const { return Op_RegP; }
623 };
624 
625 //------------------------------NeverBranchNode-------------------------------
626 // The never-taken branch.  Used to give the appearance of exiting infinite
627 // loops to those algorithms that like all paths to be reachable.  Encodes
628 // empty.
629 class NeverBranchNode : public MultiBranchNode {
630 public:
631   NeverBranchNode(Node* ctrl) : MultiBranchNode(1) {
632     init_req(0, ctrl);
633     init_class_id(Class_NeverBranch);
634   }
635   virtual int Opcode() const;
636   virtual bool pinned() const { return true; };
637   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
638   virtual const Type* Value(PhaseGVN* phase) const;
639   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
640   virtual int required_outcnt() const { return 2; }
641   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { }
642   virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
643 #ifndef PRODUCT
644   virtual void format( PhaseRegAlloc *, outputStream *st ) const;
645 #endif
646 };
647 
648 //------------------------------BlackholeNode----------------------------
649 // Blackhole all arguments. This node would survive through the compiler
650 // the effects on its arguments, and would be finally matched to nothing.
651 class BlackholeNode : public MultiNode {
652 public:
653   BlackholeNode(Node* ctrl) : MultiNode(1) {
654     init_req(TypeFunc::Control, ctrl);
655     init_class_id(Class_Blackhole);
656   }
657   virtual int   Opcode() const;
658   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
659   virtual const Type* bottom_type() const { return TypeTuple::MEMBAR; }
660 
661   const RegMask &in_RegMask(uint idx) const {
662     // Fake the incoming arguments mask for blackholes: accept all registers
663     // and all stack slots. This would avoid any redundant register moves
664     // for blackhole inputs.
665     return RegMask::All;
666   }
667 #ifndef PRODUCT
668   virtual void format(PhaseRegAlloc* ra, outputStream* st) const;
669 #endif
670 };
671 
672 
673 #endif // SHARE_OPTO_CFGNODE_HPP