1 /*
2 * Copyright (c) 1997, 2019, 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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
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 public:
68 // Node layout (parallels PhiNode):
69 enum { Region, // Generally points to self.
70 Control // Control arcs are [1..len)
71 };
72
73 RegionNode( uint required ) : Node(required) {
74 init_class_id(Class_Region);
75 init_req(0,this);
76 }
77
78 Node* is_copy() const {
79 const Node* r = _in[Region];
80 if (r == NULL)
81 return nonnull_req();
82 return NULL; // not a copy!
83 }
84 PhiNode* has_phi() const; // returns an arbitrary phi user, or NULL
85 PhiNode* has_unique_phi() const; // returns the unique phi user, or NULL
86 // Is this region node unreachable from root?
87 bool is_unreachable_region(PhaseGVN *phase) const;
88 virtual int Opcode() const;
89 virtual bool pinned() const { return (const Node *)in(0) == this; }
90 virtual bool is_CFG () const { return true; }
91 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
92 virtual bool depends_only_on_test() const { return false; }
93 virtual const Type *bottom_type() const { return Type::CONTROL; }
94 virtual const Type* Value(PhaseGVN* phase) const;
95 virtual Node* Identity(PhaseGVN* phase);
96 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
97 virtual const RegMask &out_RegMask() const;
98 bool try_clean_mem_phi(PhaseGVN *phase);
99 bool optimize_trichotomy(PhaseIterGVN* igvn);
100 };
101
102 //------------------------------JProjNode--------------------------------------
103 // jump projection for node that produces multiple control-flow paths
104 class JProjNode : public ProjNode {
105 public:
106 JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}
107 virtual int Opcode() const;
108 virtual bool is_CFG() const { return true; }
109 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
110 virtual const Node* is_block_proj() const { return in(0); }
111 virtual const RegMask& out_RegMask() const;
112 virtual uint ideal_reg() const { return 0; }
113 };
114
115 //------------------------------PhiNode----------------------------------------
116 // PhiNodes merge values from different Control paths. Slot 0 points to the
117 // controlling RegionNode. Other slots map 1-for-1 with incoming control flow
118 // paths to the RegionNode. For speed reasons (to avoid another pass) we
119 // can turn PhiNodes into copys in-place by NULL'ing out their RegionNode
120 // input in slot 0.
121 class PhiNode : public TypeNode {
122 friend class PhaseRenumberLive;
123
124 const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.
125 // The following fields are only used for data PhiNodes to indicate
126 // that the PhiNode represents the value of a known instance field.
127 int _inst_mem_id; // Instance memory id (node index of the memory Phi)
128 int _inst_id; // Instance id of the memory slice.
129 const int _inst_index; // Alias index of the instance memory slice.
130 // Array elements references have the same alias_idx but different offset.
131 const int _inst_offset; // Offset of the instance memory slice.
132 // Size is bigger to hold the _adr_type field.
133 virtual uint hash() const; // Check the type
134 virtual uint cmp( const Node &n ) const;
135 virtual uint size_of() const { return sizeof(*this); }
136
137 // Determine if CMoveNode::is_cmove_id can be used at this join point.
138 Node* is_cmove_id(PhaseTransform* phase, int true_path);
139
140 public:
141 // Node layout (parallels RegionNode):
142 enum { Region, // Control input is the Phi's region.
143 Input // Input values are [1..len)
144 };
145
146 PhiNode( Node *r, const Type *t, const TypePtr* at = NULL,
147 const int imid = -1,
148 const int iid = TypeOopPtr::InstanceTop,
149 const int iidx = Compile::AliasIdxTop,
150 const int ioffs = Type::OffsetTop )
151 : TypeNode(t,r->req()),
152 _adr_type(at),
153 _inst_mem_id(imid),
154 _inst_id(iid),
155 _inst_index(iidx),
156 _inst_offset(ioffs)
157 {
158 init_class_id(Class_Phi);
159 init_req(0, r);
160 verify_adr_type();
161 }
162 // create a new phi with in edges matching r and set (initially) to x
163 static PhiNode* make( Node* r, Node* x );
164 // extra type arguments override the new phi's bottom_type and adr_type
165 static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL );
166 // create a new phi with narrowed memory type
167 PhiNode* slice_memory(const TypePtr* adr_type) const;
168 PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;
169 // like make(r, x), but does not initialize the in edges to x
170 static PhiNode* make_blank( Node* r, Node* x );
171
172 // Accessors
173 RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; }
174
175 Node* is_copy() const {
176 // The node is a real phi if _in[0] is a Region node.
177 DEBUG_ONLY(const Node* r = _in[Region];)
178 assert(r != NULL && r->is_Region(), "Not valid control");
179 return NULL; // not a copy!
180 }
181
182 bool is_tripcount() const;
183
184 // Determine a unique non-trivial input, if any.
185 // Ignore casts if it helps. Return NULL on failure.
186 Node* unique_input(PhaseTransform *phase, bool uncast);
187 Node* unique_input(PhaseTransform *phase) {
188 Node* uin = unique_input(phase, false);
189 if (uin == NULL) {
190 uin = unique_input(phase, true);
191 }
192 return uin;
193 }
194
195 // Check for a simple dead loop.
196 enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
197 LoopSafety simple_data_loop_check(Node *in) const;
198 // Is it unsafe data loop? It becomes a dead loop if this phi node removed.
199 bool is_unsafe_data_reference(Node *in) const;
200 int is_diamond_phi(bool check_control_only = false) const;
201 virtual int Opcode() const;
202 virtual bool pinned() const { return in(0) != 0; }
203 virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; }
204
205 void set_inst_mem_id(int inst_mem_id) { _inst_mem_id = inst_mem_id; }
206 const int inst_mem_id() const { return _inst_mem_id; }
207 const int inst_id() const { return _inst_id; }
208 const int inst_index() const { return _inst_index; }
209 const int inst_offset() const { return _inst_offset; }
210 bool is_same_inst_field(const Type* tp, int mem_id, int id, int index, int offset) {
211 return type()->basic_type() == tp->basic_type() &&
212 inst_mem_id() == mem_id &&
213 inst_id() == id &&
214 inst_index() == index &&
215 inst_offset() == offset &&
216 type()->higher_equal(tp);
217 }
218
219 virtual const Type* Value(PhaseGVN* phase) const;
220 virtual Node* Identity(PhaseGVN* phase);
221 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
222 virtual const RegMask &out_RegMask() const;
223 virtual const RegMask &in_RegMask(uint) const;
224 #ifndef PRODUCT
225 virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
226 virtual void dump_spec(outputStream *st) const;
227 #endif
228 #ifdef ASSERT
229 void verify_adr_type(VectorSet& visited, const TypePtr* at) const;
230 void verify_adr_type(bool recursive = false) const;
231 #else //ASSERT
232 void verify_adr_type(bool recursive = false) const {}
233 #endif //ASSERT
234 };
235
236 //------------------------------GotoNode---------------------------------------
237 // GotoNodes perform direct branches.
238 class GotoNode : public Node {
239 public:
240 GotoNode( Node *control ) : Node(control) {}
241 virtual int Opcode() const;
242 virtual bool pinned() const { return true; }
243 virtual bool is_CFG() const { return true; }
244 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
245 virtual const Node *is_block_proj() const { return this; }
246 virtual bool depends_only_on_test() const { return false; }
247 virtual const Type *bottom_type() const { return Type::CONTROL; }
248 virtual const Type* Value(PhaseGVN* phase) const;
249 virtual Node* Identity(PhaseGVN* phase);
250 virtual const RegMask &out_RegMask() const;
251
252 #ifndef PRODUCT
253 virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
254 #endif
255 };
256
257 //------------------------------CProjNode--------------------------------------
258 // control projection for node that produces multiple control-flow paths
259 class CProjNode : public ProjNode {
260 public:
261 CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}
262 virtual int Opcode() const;
263 virtual bool is_CFG() const { return true; }
264 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
265 virtual const Node *is_block_proj() const { return in(0); }
266 virtual const RegMask &out_RegMask() const;
267 virtual uint ideal_reg() const { return 0; }
268 };
269
270 //---------------------------MultiBranchNode-----------------------------------
271 // This class defines a MultiBranchNode, a MultiNode which yields multiple
272 // control values. These are distinguished from other types of MultiNodes
273 // which yield multiple values, but control is always and only projection #0.
274 class MultiBranchNode : public MultiNode {
275 public:
276 MultiBranchNode( uint required ) : MultiNode(required) {
277 init_class_id(Class_MultiBranch);
278 }
279 // returns required number of users to be well formed.
280 virtual int required_outcnt() const = 0;
281 };
282
283 //------------------------------IfNode-----------------------------------------
284 // Output selected Control, based on a boolean test
285 class IfNode : public MultiBranchNode {
286 // Size is bigger to hold the probability field. However, _prob does not
287 // change the semantics so it does not appear in the hash & cmp functions.
288 virtual uint size_of() const { return sizeof(*this); }
289
290 private:
291 // Helper methods for fold_compares
292 bool cmpi_folds(PhaseIterGVN* igvn);
293 bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);
294 bool has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail);
295 bool has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn);
296 Node* merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
297 static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);
298 bool is_cmp_with_loadrange(ProjNode* proj);
299 bool is_null_check(ProjNode* proj, PhaseIterGVN* igvn);
300 bool is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn);
301 void reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn);
302 ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call) const;
303 bool fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
304 static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);
305
306 protected:
307 ProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r);
308 Node* Ideal_common(PhaseGVN *phase, bool can_reshape);
309 Node* search_identical(int dist);
310
311 public:
312
313 // Degrees of branch prediction probability by order of magnitude:
314 // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.
315 // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)
316 #define PROB_UNLIKELY_MAG(N) (1e- ## N ## f)
317 #define PROB_LIKELY_MAG(N) (1.0f-PROB_UNLIKELY_MAG(N))
318
319 // Maximum and minimum branch prediction probabilties
320 // 1 in 1,000,000 (magnitude 6)
321 //
322 // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX
323 // they are used to distinguish different situations:
324 //
325 // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to
326 // very likely (unlikely) but with a concrete possibility of a rare
327 // contrary case. These constants would be used for pinning
328 // measurements, and as measures for assertions that have high
329 // confidence, but some evidence of occasional failure.
330 //
331 // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which
332 // there is no evidence at all that the contrary case has ever occurred.
333
334 #define PROB_NEVER PROB_UNLIKELY_MAG(6)
335 #define PROB_ALWAYS PROB_LIKELY_MAG(6)
336
337 #define PROB_MIN PROB_UNLIKELY_MAG(6)
338 #define PROB_MAX PROB_LIKELY_MAG(6)
339
340 // Static branch prediction probabilities
341 // 1 in 10 (magnitude 1)
342 #define PROB_STATIC_INFREQUENT PROB_UNLIKELY_MAG(1)
343 #define PROB_STATIC_FREQUENT PROB_LIKELY_MAG(1)
344
345 // Fair probability 50/50
346 #define PROB_FAIR (0.5f)
347
348 // Unknown probability sentinel
349 #define PROB_UNKNOWN (-1.0f)
350
351 // Probability "constructors", to distinguish as a probability any manifest
352 // constant without a names
353 #define PROB_LIKELY(x) ((float) (x))
354 #define PROB_UNLIKELY(x) (1.0f - (float)(x))
355
356 // Other probabilities in use, but without a unique name, are documented
357 // here for lack of a better place:
358 //
359 // 1 in 1000 probabilities (magnitude 3):
360 // threshold for converting to conditional move
361 // likelihood of null check failure if a null HAS been seen before
362 // likelihood of slow path taken in library calls
363 //
364 // 1 in 10,000 probabilities (magnitude 4):
365 // threshold for making an uncommon trap probability more extreme
366 // threshold for for making a null check implicit
367 // likelihood of needing a gc if eden top moves during an allocation
368 // likelihood of a predicted call failure
369 //
370 // 1 in 100,000 probabilities (magnitude 5):
371 // threshold for ignoring counts when estimating path frequency
372 // likelihood of FP clipping failure
373 // likelihood of catching an exception from a try block
374 // likelihood of null check failure if a null has NOT been seen before
375 //
376 // Magic manifest probabilities such as 0.83, 0.7, ... can be found in
377 // gen_subtype_check() and catch_inline_exceptions().
378
379 float _prob; // Probability of true path being taken.
380 float _fcnt; // Frequency counter
381 IfNode( Node *control, Node *b, float p, float fcnt )
382 : MultiBranchNode(2), _prob(p), _fcnt(fcnt) {
383 init_class_id(Class_If);
384 init_req(0,control);
385 init_req(1,b);
386 }
387 virtual int Opcode() const;
388 virtual bool pinned() const { return true; }
389 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
390 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
391 virtual const Type* Value(PhaseGVN* phase) const;
392 virtual int required_outcnt() const { return 2; }
393 virtual const RegMask &out_RegMask() const;
394 Node* fold_compares(PhaseIterGVN* phase);
395 static Node* up_one_dom(Node* curr, bool linear_only = false);
396 Node* dominated_by(Node* prev_dom, PhaseIterGVN* igvn);
397
398 // Takes the type of val and filters it through the test represented
399 // by if_proj and returns a more refined type if one is produced.
400 // Returns NULL is it couldn't improve the type.
401 static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);
402
403 #ifndef PRODUCT
404 virtual void dump_spec(outputStream *st) const;
405 virtual void related(GrowableArray <Node *> *in_rel, GrowableArray <Node *> *out_rel, bool compact) const;
406 #endif
407 };
408
409 class RangeCheckNode : public IfNode {
410 private:
411 int is_range_check(Node* &range, Node* &index, jint &offset);
412
413 public:
414 RangeCheckNode(Node* control, Node *b, float p, float fcnt)
415 : IfNode(control, b, p, fcnt) {
416 init_class_id(Class_RangeCheck);
417 }
418
419 virtual int Opcode() const;
420 virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
421 };
422
423 class IfProjNode : public CProjNode {
424 public:
425 IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
426 virtual Node* Identity(PhaseGVN* phase);
427
428 protected:
429 // Type of If input when this branch is always taken
430 virtual bool always_taken(const TypeTuple* t) const = 0;
431
432 #ifndef PRODUCT
433 public:
434 virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
435 #endif
436 };
437
438 class IfTrueNode : public IfProjNode {
439 public:
440 IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
441 init_class_id(Class_IfTrue);
442 }
443 virtual int Opcode() const;
444
445 protected:
446 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
447 };
448
449 class IfFalseNode : public IfProjNode {
450 public:
451 IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
452 init_class_id(Class_IfFalse);
453 }
454 virtual int Opcode() const;
455
456 protected:
457 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
458 };
459
460
461 //------------------------------PCTableNode------------------------------------
462 // Build an indirect branch table. Given a control and a table index,
463 // control is passed to the Projection matching the table index. Used to
464 // implement switch statements and exception-handling capabilities.
465 // Undefined behavior if passed-in index is not inside the table.
466 class PCTableNode : public MultiBranchNode {
467 virtual uint hash() const; // Target count; table size
468 virtual uint cmp( const Node &n ) const;
469 virtual uint size_of() const { return sizeof(*this); }
470
471 public:
472 const uint _size; // Number of targets
473
474 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
475 init_class_id(Class_PCTable);
476 init_req(0, ctrl);
477 init_req(1, idx);
478 }
479 virtual int Opcode() const;
480 virtual const Type* Value(PhaseGVN* phase) const;
481 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
482 virtual const Type *bottom_type() const;
483 virtual bool pinned() const { return true; }
484 virtual int required_outcnt() const { return _size; }
485 };
486
487 //------------------------------JumpNode---------------------------------------
488 // Indirect branch. Uses PCTable above to implement a switch statement.
489 // It emits as a table load and local branch.
490 class JumpNode : public PCTableNode {
491 virtual uint size_of() const { return sizeof(*this); }
492 public:
493 float* _probs; // probability of each projection
494 float _fcnt; // total number of times this Jump was executed
495 JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
496 : PCTableNode(control, switch_val, size),
497 _probs(probs), _fcnt(cnt) {
498 init_class_id(Class_Jump);
499 }
500 virtual int Opcode() const;
501 virtual const RegMask& out_RegMask() const;
502 virtual const Node* is_block_proj() const { return this; }
503 #ifndef PRODUCT
504 virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
505 #endif
506 };
507
508 class JumpProjNode : public JProjNode {
509 virtual uint hash() const;
510 virtual uint cmp( const Node &n ) const;
511 virtual uint size_of() const { return sizeof(*this); }
512
513 private:
514 const int _dest_bci;
515 const uint _proj_no;
516 const int _switch_val;
517 public:
518 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
519 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
520 init_class_id(Class_JumpProj);
521 }
522
523 virtual int Opcode() const;
524 virtual const Type* bottom_type() const { return Type::CONTROL; }
525 int dest_bci() const { return _dest_bci; }
526 int switch_val() const { return _switch_val; }
527 uint proj_no() const { return _proj_no; }
528 #ifndef PRODUCT
529 virtual void dump_spec(outputStream *st) const;
530 virtual void dump_compact_spec(outputStream *st) const;
531 virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
532 #endif
533 };
534
535 //------------------------------CatchNode--------------------------------------
536 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by
537 // a just-prior call. Looks like a PCTableNode but emits no code - just the
538 // table. The table lookup and branch is implemented by RethrowNode.
539 class CatchNode : public PCTableNode {
540 public:
541 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
542 init_class_id(Class_Catch);
543 }
544 virtual int Opcode() const;
545 virtual const Type* Value(PhaseGVN* phase) const;
546 };
547
548 // CatchProjNode controls which exception handler is targetted after a call.
549 // It is passed in the bci of the target handler, or no_handler_bci in case
550 // the projection doesn't lead to an exception handler.
551 class CatchProjNode : public CProjNode {
552 virtual uint hash() const;
553 virtual uint cmp( const Node &n ) const;
554 virtual uint size_of() const { return sizeof(*this); }
555
556 private:
557 const int _handler_bci;
558
559 public:
560 enum {
561 fall_through_index = 0, // the fall through projection index
562 catch_all_index = 1, // the projection index for catch-alls
563 no_handler_bci = -1 // the bci for fall through or catch-all projs
564 };
565
566 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
567 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
568 init_class_id(Class_CatchProj);
569 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
570 }
571
572 virtual int Opcode() const;
573 virtual Node* Identity(PhaseGVN* phase);
574 virtual const Type *bottom_type() const { return Type::CONTROL; }
575 int handler_bci() const { return _handler_bci; }
576 bool is_handler_proj() const { return _handler_bci >= 0; }
577 #ifndef PRODUCT
578 virtual void dump_spec(outputStream *st) const;
579 #endif
580 };
581
582
583 //---------------------------------CreateExNode--------------------------------
584 // Helper node to create the exception coming back from a call
585 class CreateExNode : public TypeNode {
586 public:
587 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
588 init_req(0, control);
589 init_req(1, i_o);
590 }
591 virtual int Opcode() const;
592 virtual Node* Identity(PhaseGVN* phase);
593 virtual bool pinned() const { return true; }
594 uint match_edge(uint idx) const { return 0; }
595 virtual uint ideal_reg() const { return Op_RegP; }
596 };
597
598 //------------------------------NeverBranchNode-------------------------------
599 // The never-taken branch. Used to give the appearance of exiting infinite
600 // loops to those algorithms that like all paths to be reachable. Encodes
601 // empty.
602 class NeverBranchNode : public MultiBranchNode {
603 public:
604 NeverBranchNode( Node *ctrl ) : MultiBranchNode(1) { init_req(0,ctrl); }
605 virtual int Opcode() const;
606 virtual bool pinned() const { return true; };
607 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
608 virtual const Type* Value(PhaseGVN* phase) const;
609 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
610 virtual int required_outcnt() const { return 2; }
611 virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { }
612 virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
613 #ifndef PRODUCT
614 virtual void format( PhaseRegAlloc *, outputStream *st ) const;
615 #endif
616 };
617
618 #endif // SHARE_OPTO_CFGNODE_HPP