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  *
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 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
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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   ProjNode;
 51 class     CProjNode;
 52 class       IfTrueNode;
 53 class       IfFalseNode;
 54 class       CatchProjNode;
 55 class     JProjNode;
 56 class       JumpProjNode;
 57 class     SCMemProjNode;
 58 class PhaseIdealLoop;
 59 
 60 //------------------------------RegionNode-------------------------------------
 61 // The class of RegionNodes, which can be mapped to basic blocks in the
 62 // program.  Their inputs point to Control sources.  PhiNodes (described
 63 // below) have an input point to a RegionNode.  Merged data inputs to PhiNodes
 64 // correspond 1-to-1 with RegionNode inputs.  The zero input of a PhiNode is
 65 // the RegionNode, and the zero input of the RegionNode is itself.
 66 class RegionNode : public Node {
 67 private:
 68   bool _is_unreachable_region;
 69 
 70   bool is_possible_unsafe_loop(const PhaseGVN* phase) const;
 71   bool is_unreachable_from_root(const PhaseGVN* phase) const;
 72 public:
 73   // Node layout (parallels PhiNode):
 74   enum { Region,                // Generally points to self.
 75          Control                // Control arcs are [1..len)
 76   };
 77 
 78   RegionNode(uint required) : Node(required), _is_unreachable_region(false) {
 79     init_class_id(Class_Region);
 80     init_req(0, this);
 81   }
 82 
 83   Node* is_copy() const {
 84     const Node* r = _in[Region];
 85     if (r == NULL)
 86       return nonnull_req();
 87     return NULL;  // not a copy!
 88   }
 89   PhiNode* has_phi() const;        // returns an arbitrary phi user, or NULL
 90   PhiNode* has_unique_phi() const; // returns the unique phi user, or NULL
 91   // Is this region node unreachable from root?
 92   bool is_unreachable_region(const PhaseGVN* phase);
 93   virtual int Opcode() const;
 94   virtual uint size_of() const { return sizeof(*this); }
 95   virtual bool pinned() const { return (const Node*)in(0) == this; }
 96   virtual bool is_CFG() const { return true; }
 97   virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
 98   virtual bool depends_only_on_test() const { return false; }
 99   virtual const Type* bottom_type() const { return Type::CONTROL; }
100   virtual const Type* Value(PhaseGVN* phase) const;
101   virtual Node* Identity(PhaseGVN* phase);
102   virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
103   virtual const RegMask &out_RegMask() const;
104   bool try_clean_mem_phi(PhaseGVN* phase);
105   bool optimize_trichotomy(PhaseIterGVN* igvn);
106 };
107 
108 //------------------------------JProjNode--------------------------------------
109 // jump projection for node that produces multiple control-flow paths
110 class JProjNode : public ProjNode {
111  public:
112   JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}
113   virtual int Opcode() const;
114   virtual bool  is_CFG() const { return true; }
115   virtual uint  hash() const { return NO_HASH; }  // CFG nodes do not hash
116   virtual const Node* is_block_proj() const { return in(0); }
117   virtual const RegMask& out_RegMask() const;
118   virtual uint  ideal_reg() const { return 0; }
119 };
120 
121 //------------------------------PhiNode----------------------------------------
122 // PhiNodes merge values from different Control paths.  Slot 0 points to the
123 // controlling RegionNode.  Other slots map 1-for-1 with incoming control flow
124 // paths to the RegionNode.
125 class PhiNode : public TypeNode {
126   friend class PhaseRenumberLive;
127 
128   const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.
129   // The following fields are only used for data PhiNodes to indicate
130   // that the PhiNode represents the value of a known instance field.
131         int _inst_mem_id; // Instance memory id (node index of the memory Phi)
132         int _inst_id;     // Instance id of the memory slice.
133   const int _inst_index;  // Alias index of the instance memory slice.
134   // Array elements references have the same alias_idx but different offset.
135   const int _inst_offset; // Offset of the instance memory slice.
136   // Size is bigger to hold the _adr_type field.
137   virtual uint hash() const;    // Check the type
138   virtual bool cmp( const Node &n ) const;
139   virtual uint size_of() const { return sizeof(*this); }
140 
141   // Determine if CMoveNode::is_cmove_id can be used at this join point.
142   Node* is_cmove_id(PhaseTransform* phase, int true_path);
143   bool wait_for_region_igvn(PhaseGVN* phase);
144   bool is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase);
145 
146 public:
147   // Node layout (parallels RegionNode):
148   enum { Region,                // Control input is the Phi's region.
149          Input                  // Input values are [1..len)
150   };
151 
152   PhiNode( Node *r, const Type *t, const TypePtr* at = NULL,
153            const int imid = -1,
154            const int iid = TypeOopPtr::InstanceTop,
155            const int iidx = Compile::AliasIdxTop,
156            const int ioffs = Type::OffsetTop )
157     : TypeNode(t,r->req()),
158       _adr_type(at),
159       _inst_mem_id(imid),
160       _inst_id(iid),
161       _inst_index(iidx),
162       _inst_offset(ioffs)
163   {
164     init_class_id(Class_Phi);
165     init_req(0, r);
166     verify_adr_type();
167   }
168   // create a new phi with in edges matching r and set (initially) to x
169   static PhiNode* make( Node* r, Node* x );
170   // extra type arguments override the new phi's bottom_type and adr_type
171   static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL );
172   // create a new phi with narrowed memory type
173   PhiNode* slice_memory(const TypePtr* adr_type) const;
174   PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;
175   // like make(r, x), but does not initialize the in edges to x
176   static PhiNode* make_blank( Node* r, Node* x );
177 
178   // Accessors
179   RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; }
180 
181   bool is_tripcount(BasicType bt) const;
182 
183   // Determine a unique non-trivial input, if any.
184   // Ignore casts if it helps.  Return NULL on failure.
185   Node* unique_input(PhaseTransform *phase, bool uncast);
186   Node* unique_input(PhaseTransform *phase) {
187     Node* uin = unique_input(phase, false);
188     if (uin == NULL) {
189       uin = unique_input(phase, true);
190     }
191     return uin;
192   }
193 
194   // Check for a simple dead loop.
195   enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
196   LoopSafety simple_data_loop_check(Node *in) const;
197   // Is it unsafe data loop? It becomes a dead loop if this phi node removed.
198   bool is_unsafe_data_reference(Node *in) const;
199   int  is_diamond_phi(bool check_control_only = false) const;
200   virtual int Opcode() const;
201   virtual bool pinned() const { return in(0) != 0; }
202   virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; }
203 
204   void  set_inst_mem_id(int inst_mem_id) { _inst_mem_id = inst_mem_id; }
205   const int inst_mem_id() const { return _inst_mem_id; }
206   const int inst_id()     const { return _inst_id; }
207   const int inst_index()  const { return _inst_index; }
208   const int inst_offset() const { return _inst_offset; }
209   bool is_same_inst_field(const Type* tp, int mem_id, int id, int index, int offset) {
210     return type()->basic_type() == tp->basic_type() &&
211            inst_mem_id() == mem_id &&
212            inst_id()     == id     &&
213            inst_index()  == index  &&
214            inst_offset() == offset &&
215            type()->higher_equal(tp);
216   }



217 
218   virtual const Type* Value(PhaseGVN* phase) const;
219   virtual Node* Identity(PhaseGVN* phase);
220   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
221   virtual const RegMask &out_RegMask() const;
222   virtual const RegMask &in_RegMask(uint) const;
223 #ifndef PRODUCT
224   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
225   virtual void dump_spec(outputStream *st) const;
226 #endif
227 #ifdef ASSERT
228   void verify_adr_type(VectorSet& visited, const TypePtr* at) const;
229   void verify_adr_type(bool recursive = false) const;
230 #else //ASSERT
231   void verify_adr_type(bool recursive = false) const {}
232 #endif //ASSERT
233 };
234 
235 //------------------------------GotoNode---------------------------------------
236 // GotoNodes perform direct branches.
237 class GotoNode : public Node {
238 public:
239   GotoNode( Node *control ) : Node(control) {}
240   virtual int Opcode() const;
241   virtual bool pinned() const { return true; }
242   virtual bool  is_CFG() const { return true; }
243   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
244   virtual const Node *is_block_proj() const { return this; }
245   virtual bool depends_only_on_test() const { return false; }
246   virtual const Type *bottom_type() const { return Type::CONTROL; }
247   virtual const Type* Value(PhaseGVN* phase) const;
248   virtual Node* Identity(PhaseGVN* phase);
249   virtual const RegMask &out_RegMask() const;
250 
251 #ifndef PRODUCT
252   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
253 #endif
254 };
255 
256 //------------------------------CProjNode--------------------------------------
257 // control projection for node that produces multiple control-flow paths
258 class CProjNode : public ProjNode {
259 public:
260   CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}
261   virtual int Opcode() const;
262   virtual bool  is_CFG() const { return true; }
263   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
264   virtual const Node *is_block_proj() const { return in(0); }
265   virtual const RegMask &out_RegMask() const;
266   virtual uint ideal_reg() const { return 0; }
267 };
268 
269 //---------------------------MultiBranchNode-----------------------------------
270 // This class defines a MultiBranchNode, a MultiNode which yields multiple
271 // control values. These are distinguished from other types of MultiNodes
272 // which yield multiple values, but control is always and only projection #0.
273 class MultiBranchNode : public MultiNode {
274 public:
275   MultiBranchNode( uint required ) : MultiNode(required) {
276     init_class_id(Class_MultiBranch);
277   }
278   // returns required number of users to be well formed.
279   virtual int required_outcnt() const = 0;
280 };
281 
282 //------------------------------IfNode-----------------------------------------
283 // Output selected Control, based on a boolean test
284 class IfNode : public MultiBranchNode {
285   // Size is bigger to hold the probability field.  However, _prob does not
286   // change the semantics so it does not appear in the hash & cmp functions.
287   virtual uint size_of() const { return sizeof(*this); }
288 
289 private:
290   // Helper methods for fold_compares
291   bool cmpi_folds(PhaseIterGVN* igvn, bool fold_ne = false);
292   bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);
293   bool has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail);
294   bool has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn);
295   Node* merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
296   static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);
297   bool is_cmp_with_loadrange(ProjNode* proj);
298   bool is_null_check(ProjNode* proj, PhaseIterGVN* igvn);
299   bool is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn);
300   void reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn);
301   ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call) const;
302   bool fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
303   static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);
304 
305 protected:
306   ProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r);
307   Node* Ideal_common(PhaseGVN *phase, bool can_reshape);
308   Node* search_identical(int dist);
309 
310   Node* simple_subsuming(PhaseIterGVN* igvn);
311 
312 public:
313 
314   // Degrees of branch prediction probability by order of magnitude:
315   // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.
316   // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)
317 #define PROB_UNLIKELY_MAG(N)    (1e- ## N ## f)
318 #define PROB_LIKELY_MAG(N)      (1.0f-PROB_UNLIKELY_MAG(N))
319 
320   // Maximum and minimum branch prediction probabilties
321   // 1 in 1,000,000 (magnitude 6)
322   //
323   // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX
324   // they are used to distinguish different situations:
325   //
326   // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to
327   // very likely (unlikely) but with a concrete possibility of a rare
328   // contrary case.  These constants would be used for pinning
329   // measurements, and as measures for assertions that have high
330   // confidence, but some evidence of occasional failure.
331   //
332   // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which
333   // there is no evidence at all that the contrary case has ever occurred.
334 
335 #define PROB_NEVER              PROB_UNLIKELY_MAG(6)
336 #define PROB_ALWAYS             PROB_LIKELY_MAG(6)
337 
338 #define PROB_MIN                PROB_UNLIKELY_MAG(6)
339 #define PROB_MAX                PROB_LIKELY_MAG(6)
340 
341   // Static branch prediction probabilities
342   // 1 in 10 (magnitude 1)
343 #define PROB_STATIC_INFREQUENT  PROB_UNLIKELY_MAG(1)
344 #define PROB_STATIC_FREQUENT    PROB_LIKELY_MAG(1)
345 
346   // Fair probability 50/50
347 #define PROB_FAIR               (0.5f)
348 
349   // Unknown probability sentinel
350 #define PROB_UNKNOWN            (-1.0f)
351 
352   // Probability "constructors", to distinguish as a probability any manifest
353   // constant without a names
354 #define PROB_LIKELY(x)          ((float) (x))
355 #define PROB_UNLIKELY(x)        (1.0f - (float)(x))
356 
357   // Other probabilities in use, but without a unique name, are documented
358   // here for lack of a better place:
359   //
360   // 1 in 1000 probabilities (magnitude 3):
361   //     threshold for converting to conditional move
362   //     likelihood of null check failure if a null HAS been seen before
363   //     likelihood of slow path taken in library calls
364   //
365   // 1 in 10,000 probabilities (magnitude 4):
366   //     threshold for making an uncommon trap probability more extreme
367   //     threshold for for making a null check implicit
368   //     likelihood of needing a gc if eden top moves during an allocation
369   //     likelihood of a predicted call failure
370   //
371   // 1 in 100,000 probabilities (magnitude 5):
372   //     threshold for ignoring counts when estimating path frequency
373   //     likelihood of FP clipping failure
374   //     likelihood of catching an exception from a try block
375   //     likelihood of null check failure if a null has NOT been seen before
376   //
377   // Magic manifest probabilities such as 0.83, 0.7, ... can be found in
378   // gen_subtype_check() and catch_inline_exceptions().
379 
380   float _prob;                  // Probability of true path being taken.
381   float _fcnt;                  // Frequency counter
382   IfNode( Node *control, Node *b, float p, float fcnt )
383     : MultiBranchNode(2), _prob(p), _fcnt(fcnt) {
384     init_class_id(Class_If);
385     init_req(0,control);
386     init_req(1,b);
387   }
388   virtual int Opcode() const;
389   virtual bool pinned() const { return true; }
390   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
391   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
392   virtual const Type* Value(PhaseGVN* phase) const;
393   virtual int required_outcnt() const { return 2; }
394   virtual const RegMask &out_RegMask() const;
395   Node* fold_compares(PhaseIterGVN* phase);
396   static Node* up_one_dom(Node* curr, bool linear_only = false);
397   Node* dominated_by(Node* prev_dom, PhaseIterGVN* igvn);
398 
399   // Takes the type of val and filters it through the test represented
400   // by if_proj and returns a more refined type if one is produced.
401   // Returns NULL is it couldn't improve the type.
402   static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);
403 


404 #ifndef PRODUCT
405   virtual void dump_spec(outputStream *st) const;
406   virtual void related(GrowableArray <Node *> *in_rel, GrowableArray <Node *> *out_rel, bool compact) const;
407 #endif
408 };
409 
410 class RangeCheckNode : public IfNode {
411 private:
412   int is_range_check(Node* &range, Node* &index, jint &offset);
413 
414 public:
415   RangeCheckNode(Node* control, Node *b, float p, float fcnt)
416     : IfNode(control, b, p, fcnt) {
417     init_class_id(Class_RangeCheck);
418   }
419 
420   virtual int Opcode() const;
421   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
422 };
423 
424 class IfProjNode : public CProjNode {
425 public:
426   IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
427   virtual Node* Identity(PhaseGVN* phase);
428 
429 protected:
430   // Type of If input when this branch is always taken
431   virtual bool always_taken(const TypeTuple* t) const = 0;
432 
433 #ifndef PRODUCT
434 public:
435   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
436 #endif
437 };
438 
439 class IfTrueNode : public IfProjNode {
440 public:
441   IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
442     init_class_id(Class_IfTrue);
443   }
444   virtual int Opcode() const;
445 
446 protected:
447   virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
448 };
449 
450 class IfFalseNode : public IfProjNode {
451 public:
452   IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
453     init_class_id(Class_IfFalse);
454   }
455   virtual int Opcode() const;
456 
457 protected:
458   virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
459 };
460 
461 
462 //------------------------------PCTableNode------------------------------------
463 // Build an indirect branch table.  Given a control and a table index,
464 // control is passed to the Projection matching the table index.  Used to
465 // implement switch statements and exception-handling capabilities.
466 // Undefined behavior if passed-in index is not inside the table.
467 class PCTableNode : public MultiBranchNode {
468   virtual uint hash() const;    // Target count; table size
469   virtual bool cmp( const Node &n ) const;
470   virtual uint size_of() const { return sizeof(*this); }
471 
472 public:
473   const uint _size;             // Number of targets
474 
475   PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
476     init_class_id(Class_PCTable);
477     init_req(0, ctrl);
478     init_req(1, idx);
479   }
480   virtual int Opcode() const;
481   virtual const Type* Value(PhaseGVN* phase) const;
482   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
483   virtual const Type *bottom_type() const;
484   virtual bool pinned() const { return true; }
485   virtual int required_outcnt() const { return _size; }
486 };
487 
488 //------------------------------JumpNode---------------------------------------
489 // Indirect branch.  Uses PCTable above to implement a switch statement.
490 // It emits as a table load and local branch.
491 class JumpNode : public PCTableNode {
492   virtual uint size_of() const { return sizeof(*this); }
493 public:
494   float* _probs; // probability of each projection
495   float _fcnt;   // total number of times this Jump was executed
496   JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
497     : PCTableNode(control, switch_val, size),
498       _probs(probs), _fcnt(cnt) {
499     init_class_id(Class_Jump);
500   }
501   virtual int   Opcode() const;
502   virtual const RegMask& out_RegMask() const;
503   virtual const Node* is_block_proj() const { return this; }
504 #ifndef PRODUCT
505   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
506 #endif
507 };
508 
509 class JumpProjNode : public JProjNode {
510   virtual uint hash() const;
511   virtual bool cmp( const Node &n ) const;
512   virtual uint size_of() const { return sizeof(*this); }
513 
514  private:
515   const int  _dest_bci;
516   const uint _proj_no;
517   const int  _switch_val;
518  public:
519   JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
520     : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
521     init_class_id(Class_JumpProj);
522   }
523 
524   virtual int Opcode() const;
525   virtual const Type* bottom_type() const { return Type::CONTROL; }
526   int  dest_bci()    const { return _dest_bci; }
527   int  switch_val()  const { return _switch_val; }
528   uint proj_no()     const { return _proj_no; }
529 #ifndef PRODUCT
530   virtual void dump_spec(outputStream *st) const;
531   virtual void dump_compact_spec(outputStream *st) const;
532   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
533 #endif
534 };
535 
536 //------------------------------CatchNode--------------------------------------
537 // Helper node to fork exceptions.  "Catch" catches any exceptions thrown by
538 // a just-prior call.  Looks like a PCTableNode but emits no code - just the
539 // table.  The table lookup and branch is implemented by RethrowNode.
540 class CatchNode : public PCTableNode {
541 public:
542   CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
543     init_class_id(Class_Catch);
544   }
545   virtual int Opcode() const;
546   virtual const Type* Value(PhaseGVN* phase) const;
547 };
548 
549 // CatchProjNode controls which exception handler is targetted after a call.
550 // It is passed in the bci of the target handler, or no_handler_bci in case
551 // the projection doesn't lead to an exception handler.
552 class CatchProjNode : public CProjNode {
553   virtual uint hash() const;
554   virtual bool cmp( const Node &n ) const;
555   virtual uint size_of() const { return sizeof(*this); }
556 
557 private:
558   const int _handler_bci;
559 
560 public:
561   enum {
562     fall_through_index =  0,      // the fall through projection index
563     catch_all_index    =  1,      // the projection index for catch-alls
564     no_handler_bci     = -1       // the bci for fall through or catch-all projs
565   };
566 
567   CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
568     : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
569     init_class_id(Class_CatchProj);
570     assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
571   }
572 
573   virtual int Opcode() const;
574   virtual Node* Identity(PhaseGVN* phase);
575   virtual const Type *bottom_type() const { return Type::CONTROL; }
576   int  handler_bci() const        { return _handler_bci; }
577   bool is_handler_proj() const    { return _handler_bci >= 0; }
578 #ifndef PRODUCT
579   virtual void dump_spec(outputStream *st) const;
580 #endif
581 };
582 
583 
584 //---------------------------------CreateExNode--------------------------------
585 // Helper node to create the exception coming back from a call
586 class CreateExNode : public TypeNode {
587 public:
588   CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
589     init_req(0, control);
590     init_req(1, i_o);
591   }
592   virtual int Opcode() const;
593   virtual Node* Identity(PhaseGVN* phase);
594   virtual bool pinned() const { return true; }
595   uint match_edge(uint idx) const { return 0; }
596   virtual uint ideal_reg() const { return Op_RegP; }
597 };
598 
599 //------------------------------NeverBranchNode-------------------------------
600 // The never-taken branch.  Used to give the appearance of exiting infinite
601 // loops to those algorithms that like all paths to be reachable.  Encodes
602 // empty.
603 class NeverBranchNode : public MultiBranchNode {
604 public:
605   NeverBranchNode( Node *ctrl ) : MultiBranchNode(1) { init_req(0,ctrl); }
606   virtual int Opcode() const;
607   virtual bool pinned() const { return true; };
608   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
609   virtual const Type* Value(PhaseGVN* phase) const;
610   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
611   virtual int required_outcnt() const { return 2; }
612   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { }
613   virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
614 #ifndef PRODUCT
615   virtual void format( PhaseRegAlloc *, outputStream *st ) const;
616 #endif
617 };
618 
619 #endif // SHARE_OPTO_CFGNODE_HPP
--- EOF ---