1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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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/predicates_enums.hpp"
32 #include "opto/type.hpp"
33
34 // Portions of code courtesy of Clifford Click
35
36 // Optimization - Graph Style
37
38 class Matcher;
39 class Node;
40 class RegionNode;
41 class TypeNode;
42 class PhiNode;
43 class GotoNode;
44 class MultiNode;
45 class MultiBranchNode;
46 class IfNode;
47 class PCTableNode;
48 class JumpNode;
49 class CatchNode;
50 class NeverBranchNode;
51 class BlackholeNode;
52 class ProjNode;
53 class CProjNode;
54 class IfTrueNode;
55 class IfFalseNode;
56 class CatchProjNode;
57 class JProjNode;
58 class JumpProjNode;
59 class SCMemProjNode;
60 class PhaseIdealLoop;
61 enum class AssertionPredicateType;
62 enum class PredicateState;
63
64 //------------------------------RegionNode-------------------------------------
65 // The class of RegionNodes, which can be mapped to basic blocks in the
66 // program. Their inputs point to Control sources. PhiNodes (described
67 // below) have an input point to a RegionNode. Merged data inputs to PhiNodes
68 // correspond 1-to-1 with RegionNode inputs. The zero input of a PhiNode is
69 // the RegionNode, and the zero input of the RegionNode is itself.
70 class RegionNode : public Node {
71 public:
72 enum LoopStatus {
73 // No guarantee: the region may be an irreducible loop entry, thus we have to
74 // be careful when removing entry control to it.
75 MaybeIrreducibleEntry,
76 // Limited guarantee: this region may be (nested) inside an irreducible loop,
77 // but it will never be an irreducible loop entry.
78 NeverIrreducibleEntry,
79 // Strong guarantee: this region is not (nested) inside an irreducible loop.
80 Reducible,
81 };
82
83 private:
84 bool _is_unreachable_region;
85 LoopStatus _loop_status;
86
87 bool is_possible_unsafe_loop(const PhaseGVN* phase) const;
88 bool is_unreachable_from_root(const PhaseGVN* phase) const;
89 public:
90 // Node layout (parallels PhiNode):
91 enum { Region, // Generally points to self.
92 Control // Control arcs are [1..len)
93 };
94
95 RegionNode(uint required)
96 : Node(required),
97 _is_unreachable_region(false),
98 _loop_status(LoopStatus::NeverIrreducibleEntry)
99 {
100 init_class_id(Class_Region);
101 init_req(0, this);
102 }
103
104 Node* is_copy() const {
105 const Node* r = _in[Region];
106 if (r == nullptr)
107 return nonnull_req();
108 return nullptr; // not a copy!
109 }
110 PhiNode* has_phi() const; // returns an arbitrary phi user, or null
111 PhiNode* has_unique_phi() const; // returns the unique phi user, or null
112 // Is this region node unreachable from root?
113 bool is_unreachable_region(const PhaseGVN* phase);
114 #ifdef ASSERT
115 bool is_in_infinite_subgraph();
116 static bool are_all_nodes_in_infinite_subgraph(Unique_Node_List& worklist);
117 #endif //ASSERT
118 LoopStatus loop_status() const { return _loop_status; };
119 void set_loop_status(LoopStatus status);
120 bool can_be_irreducible_entry() const;
121
122 virtual int Opcode() const;
123 virtual uint size_of() const { return sizeof(*this); }
124 virtual bool pinned() const { return (const Node*)in(0) == this; }
125 virtual bool is_CFG() const { return true; }
126 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
127 virtual bool depends_only_on_test() const { return false; }
128 virtual const Type* bottom_type() const { return Type::CONTROL; }
129 virtual const Type* Value(PhaseGVN* phase) const;
130 virtual Node* Identity(PhaseGVN* phase);
131 virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
132 void remove_unreachable_subgraph(PhaseIterGVN* igvn);
133 virtual const RegMask &out_RegMask() const;
134 bool is_diamond() const;
135 void try_clean_mem_phis(PhaseIterGVN* phase);
136 bool optimize_trichotomy(PhaseIterGVN* igvn);
137 NOT_PRODUCT(virtual void dump_spec(outputStream* st) const;)
138 };
139
140 //------------------------------JProjNode--------------------------------------
141 // jump projection for node that produces multiple control-flow paths
142 class JProjNode : public ProjNode {
143 public:
144 JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}
145 virtual int Opcode() const;
146 virtual bool is_CFG() const { return true; }
147 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
148 virtual const Node* is_block_proj() const { return in(0); }
149 virtual const RegMask& out_RegMask() const;
150 virtual uint ideal_reg() const { return 0; }
151 };
152
153 //------------------------------PhiNode----------------------------------------
154 // PhiNodes merge values from different Control paths. Slot 0 points to the
155 // controlling RegionNode. Other slots map 1-for-1 with incoming control flow
156 // paths to the RegionNode.
157 class PhiNode : public TypeNode {
158 friend class PhaseRenumberLive;
159
160 const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.
161 // The following fields are only used for data PhiNodes to indicate
162 // that the PhiNode represents the value of a known instance field.
163 int _inst_mem_id; // Instance memory id (node index of the memory Phi)
164 int _inst_id; // Instance id of the memory slice.
165 const int _inst_index; // Alias index of the instance memory slice.
166 // Array elements references have the same alias_idx but different offset.
167 const int _inst_offset; // Offset of the instance memory slice.
168 // Size is bigger to hold the _adr_type field.
169 virtual uint hash() const; // Check the type
170 virtual bool cmp( const Node &n ) const;
171 virtual uint size_of() const { return sizeof(*this); }
172
173 // Determine if CMoveNode::is_cmove_id can be used at this join point.
174 Node* is_cmove_id(PhaseTransform* phase, int true_path);
175 bool wait_for_region_igvn(PhaseGVN* phase);
176 bool is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase);
177
178 static Node* clone_through_phi(Node* root_phi, const Type* t, uint c, PhaseIterGVN* igvn);
179 static Node* merge_through_phi(Node* root_phi, PhaseIterGVN* igvn);
180
181 bool must_wait_for_region_in_irreducible_loop(PhaseGVN* phase) const;
182
183 bool can_push_inline_types_down(PhaseGVN* phase, bool can_reshape, ciInlineKlass*& inline_klass);
184 InlineTypeNode* push_inline_types_down(PhaseGVN* phase, bool can_reshape, ciInlineKlass* inline_klass);
185
186 bool is_split_through_mergemem_terminating() const;
187
188 public:
189 // Node layout (parallels RegionNode):
190 enum { Region, // Control input is the Phi's region.
191 Input // Input values are [1..len)
192 };
193
194 PhiNode( Node *r, const Type *t, const TypePtr* at = nullptr,
195 const int imid = -1,
196 const int iid = TypeOopPtr::InstanceTop,
197 const int iidx = Compile::AliasIdxTop,
198 const int ioffs = Type::OffsetTop )
199 : TypeNode(t,r->req()),
200 _adr_type(at),
201 _inst_mem_id(imid),
202 _inst_id(iid),
203 _inst_index(iidx),
204 _inst_offset(ioffs)
205 {
206 init_class_id(Class_Phi);
207 init_req(0, r);
208 verify_adr_type();
209 }
210 // create a new phi with in edges matching r and set (initially) to x
211 static PhiNode* make( Node* r, Node* x );
212 // extra type arguments override the new phi's bottom_type and adr_type
213 static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = nullptr );
214 // create a new phi with narrowed memory type
215 PhiNode* slice_memory(const TypePtr* adr_type) const;
216 PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;
217 // like make(r, x), but does not initialize the in edges to x
218 static PhiNode* make_blank( Node* r, Node* x );
219
220 // Accessors
221 RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; }
222
223 bool is_tripcount(BasicType bt) const;
224
225 // Determine a unique non-trivial input, if any.
226 // Ignore casts if it helps. Return null on failure.
227 Node* unique_input(PhaseValues* phase, bool uncast);
228 Node* unique_input(PhaseValues* phase) {
229 Node* uin = unique_input(phase, false);
230 if (uin == nullptr) {
231 uin = unique_input(phase, true);
232 }
233 return uin;
234 }
235
236 // Check for a simple dead loop.
237 enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
238 LoopSafety simple_data_loop_check(Node *in) const;
239 // Is it unsafe data loop? It becomes a dead loop if this phi node removed.
240 bool is_unsafe_data_reference(Node *in) const;
241 int is_diamond_phi() const;
242 bool try_clean_memory_phi(PhaseIterGVN* igvn);
243 virtual int Opcode() const;
244 virtual bool pinned() const { return in(0) != nullptr; }
245 virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; }
246
247 void set_inst_mem_id(int inst_mem_id) { _inst_mem_id = inst_mem_id; }
248 int inst_mem_id() const { return _inst_mem_id; }
249 int inst_id() const { return _inst_id; }
250 int inst_index() const { return _inst_index; }
251 int inst_offset() const { return _inst_offset; }
252 bool is_same_inst_field(const Type* tp, int mem_id, int id, int index, int offset) {
253 return type()->basic_type() == tp->basic_type() &&
254 inst_mem_id() == mem_id &&
255 inst_id() == id &&
256 inst_index() == index &&
257 inst_offset() == offset &&
258 type()->higher_equal(tp);
259 }
260
261 bool can_be_inline_type() const {
262 return EnableValhalla && _type->isa_instptr() && _type->is_instptr()->can_be_inline_type();
263 }
264
265 Node* try_push_inline_types_down(PhaseGVN* phase, bool can_reshape);
266 DEBUG_ONLY(bool can_push_inline_types_down(PhaseGVN* phase);)
267
268 virtual const Type* Value(PhaseGVN* phase) const;
269 virtual Node* Identity(PhaseGVN* phase);
270 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
271 virtual const RegMask &out_RegMask() const;
272 virtual const RegMask &in_RegMask(uint) const;
273 #ifndef PRODUCT
274 virtual void dump_spec(outputStream *st) const;
275 #endif
276 #ifdef ASSERT
277 void verify_adr_type(VectorSet& visited, const TypePtr* at) const;
278 void verify_adr_type(bool recursive = false) const;
279 #else //ASSERT
280 void verify_adr_type(bool recursive = false) const {}
281 #endif //ASSERT
282
283 const TypeTuple* collect_types(PhaseGVN* phase) const;
284 };
285
286 //------------------------------GotoNode---------------------------------------
287 // GotoNodes perform direct branches.
288 class GotoNode : public Node {
289 public:
290 GotoNode( Node *control ) : Node(control) {}
291 virtual int Opcode() const;
292 virtual bool pinned() const { return true; }
293 virtual bool is_CFG() const { return true; }
294 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
295 virtual const Node *is_block_proj() const { return this; }
296 virtual bool depends_only_on_test() const { return false; }
297 virtual const Type *bottom_type() const { return Type::CONTROL; }
298 virtual const Type* Value(PhaseGVN* phase) const;
299 virtual Node* Identity(PhaseGVN* phase);
300 virtual const RegMask &out_RegMask() const;
301 };
302
303 //------------------------------CProjNode--------------------------------------
304 // control projection for node that produces multiple control-flow paths
305 class CProjNode : public ProjNode {
306 public:
307 CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}
308 virtual int Opcode() const;
309 virtual bool is_CFG() const { return true; }
310 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
311 virtual const Node *is_block_proj() const { return in(0); }
312 virtual const RegMask &out_RegMask() const;
313 virtual uint ideal_reg() const { return 0; }
314 };
315
316 //---------------------------MultiBranchNode-----------------------------------
317 // This class defines a MultiBranchNode, a MultiNode which yields multiple
318 // control values. These are distinguished from other types of MultiNodes
319 // which yield multiple values, but control is always and only projection #0.
320 class MultiBranchNode : public MultiNode {
321 public:
322 MultiBranchNode( uint required ) : MultiNode(required) {
323 init_class_id(Class_MultiBranch);
324 }
325 // returns required number of users to be well formed.
326 virtual int required_outcnt() const = 0;
327 };
328
329 //------------------------------IfNode-----------------------------------------
330 // Output selected Control, based on a boolean test
331 class IfNode : public MultiBranchNode {
332 public:
333 float _prob; // Probability of true path being taken.
334 float _fcnt; // Frequency counter
335
336 private:
337 AssertionPredicateType _assertion_predicate_type;
338
339 void init_node(Node* control, Node* bol) {
340 init_class_id(Class_If);
341 init_req(0, control);
342 init_req(1, bol);
343 }
344
345 // Size is bigger to hold the probability field. However, _prob does not
346 // change the semantics so it does not appear in the hash & cmp functions.
347 virtual uint size_of() const { return sizeof(*this); }
348
349 // Helper methods for fold_compares
350 bool cmpi_folds(PhaseIterGVN* igvn, bool fold_ne = false);
351 bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);
352 bool has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail);
353 bool has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn);
354 Node* merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
355 static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);
356 bool is_cmp_with_loadrange(ProjNode* proj);
357 bool is_null_check(ProjNode* proj, PhaseIterGVN* igvn);
358 bool is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn);
359 void reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn);
360 bool fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);
361 static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);
362
363 protected:
364 ProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r);
365 Node* Ideal_common(PhaseGVN *phase, bool can_reshape);
366 Node* search_identical(int dist, PhaseIterGVN* igvn);
367
368 Node* simple_subsuming(PhaseIterGVN* igvn);
369
370 public:
371
372 // Degrees of branch prediction probability by order of magnitude:
373 // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.
374 // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)
375 #define PROB_UNLIKELY_MAG(N) (1e- ## N ## f)
376 #define PROB_LIKELY_MAG(N) (1.0f-PROB_UNLIKELY_MAG(N))
377
378 // Maximum and minimum branch prediction probabilties
379 // 1 in 1,000,000 (magnitude 6)
380 //
381 // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX
382 // they are used to distinguish different situations:
383 //
384 // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to
385 // very likely (unlikely) but with a concrete possibility of a rare
386 // contrary case. These constants would be used for pinning
387 // measurements, and as measures for assertions that have high
388 // confidence, but some evidence of occasional failure.
389 //
390 // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which
391 // there is no evidence at all that the contrary case has ever occurred.
392
393 #define PROB_NEVER PROB_UNLIKELY_MAG(6)
394 #define PROB_ALWAYS PROB_LIKELY_MAG(6)
395
396 #define PROB_MIN PROB_UNLIKELY_MAG(6)
397 #define PROB_MAX PROB_LIKELY_MAG(6)
398
399 // Static branch prediction probabilities
400 // 1 in 10 (magnitude 1)
401 #define PROB_STATIC_INFREQUENT PROB_UNLIKELY_MAG(1)
402 #define PROB_STATIC_FREQUENT PROB_LIKELY_MAG(1)
403
404 // Fair probability 50/50
405 #define PROB_FAIR (0.5f)
406
407 // Unknown probability sentinel
408 #define PROB_UNKNOWN (-1.0f)
409
410 // Probability "constructors", to distinguish as a probability any manifest
411 // constant without a names
412 #define PROB_LIKELY(x) ((float) (x))
413 #define PROB_UNLIKELY(x) (1.0f - (float)(x))
414
415 // Other probabilities in use, but without a unique name, are documented
416 // here for lack of a better place:
417 //
418 // 1 in 1000 probabilities (magnitude 3):
419 // threshold for converting to conditional move
420 // likelihood of null check failure if a null HAS been seen before
421 // likelihood of slow path taken in library calls
422 //
423 // 1 in 10,000 probabilities (magnitude 4):
424 // threshold for making an uncommon trap probability more extreme
425 // threshold for for making a null check implicit
426 // likelihood of needing a gc if eden top moves during an allocation
427 // likelihood of a predicted call failure
428 //
429 // 1 in 100,000 probabilities (magnitude 5):
430 // threshold for ignoring counts when estimating path frequency
431 // likelihood of FP clipping failure
432 // likelihood of catching an exception from a try block
433 // likelihood of null check failure if a null has NOT been seen before
434 //
435 // Magic manifest probabilities such as 0.83, 0.7, ... can be found in
436 // gen_subtype_check() and catch_inline_exceptions().
437
438 IfNode(Node* control, Node* bol, float p, float fcnt);
439 IfNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type);
440
441 static IfNode* make_with_same_profile(IfNode* if_node_profile, Node* ctrl, Node* bol);
442
443 virtual int Opcode() const;
444 virtual bool pinned() const { return true; }
445 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
446 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
447 virtual const Type* Value(PhaseGVN* phase) const;
448 virtual int required_outcnt() const { return 2; }
449 virtual const RegMask &out_RegMask() const;
450 Node* fold_compares(PhaseIterGVN* phase);
451 static Node* up_one_dom(Node* curr, bool linear_only = false);
452 bool is_zero_trip_guard() const;
453 Node* dominated_by(Node* prev_dom, PhaseIterGVN* igvn, bool pin_array_access_nodes);
454 ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call, Deoptimization::DeoptReason reason = Deoptimization::Reason_none) const;
455
456 // Takes the type of val and filters it through the test represented
457 // by if_proj and returns a more refined type if one is produced.
458 // Returns null is it couldn't improve the type.
459 static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);
460
461 bool is_flat_array_check(PhaseTransform* phase, Node** array = nullptr);
462
463 AssertionPredicateType assertion_predicate_type() const {
464 return _assertion_predicate_type;
465 }
466
467 #ifndef PRODUCT
468 virtual void dump_spec(outputStream *st) const;
469 #endif
470
471 bool same_condition(const Node* dom, PhaseIterGVN* igvn) const;
472 };
473
474 class RangeCheckNode : public IfNode {
475 private:
476 int is_range_check(Node*& range, Node*& index, jint& offset);
477
478 public:
479 RangeCheckNode(Node* control, Node* bol, float p, float fcnt) : IfNode(control, bol, p, fcnt) {
480 init_class_id(Class_RangeCheck);
481 }
482
483 RangeCheckNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type)
484 : IfNode(control, bol, p, fcnt, assertion_predicate_type) {
485 init_class_id(Class_RangeCheck);
486 }
487
488 virtual int Opcode() const;
489 virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
490 };
491
492 // Special node that denotes a Parse Predicate added during parsing. A Parse Predicate serves as placeholder to later
493 // create Regular Predicates (Runtime Predicates with possible Assertion Predicates) above it. Together they form a
494 // Predicate Block. The Parse Predicate and Regular Predicates share the same uncommon trap.
495 // There are three kinds of Parse Predicates:
496 // Loop Parse Predicate, Profiled Loop Parse Predicate (both used by Loop Predication), and Loop Limit Check Parse
497 // Predicate (used for integer overflow checks when creating a counted loop).
498 // More information about predicates can be found in loopPredicate.cpp.
499 class ParsePredicateNode : public IfNode {
500 Deoptimization::DeoptReason _deopt_reason;
501
502 // When a Parse Predicate loses its connection to a loop head, it will be marked useless by
503 // EliminateUselessPredicates and cleaned up by Value(). It can also become useless when cloning it to both loops
504 // during Loop Multiversioning - we no longer use the old version.
505 PredicateState _predicate_state;
506 public:
507 ParsePredicateNode(Node* control, Deoptimization::DeoptReason deopt_reason, PhaseGVN* gvn);
508 virtual int Opcode() const;
509 virtual uint size_of() const { return sizeof(*this); }
510
511 Deoptimization::DeoptReason deopt_reason() const {
512 return _deopt_reason;
513 }
514
515 bool is_useless() const {
516 return _predicate_state == PredicateState::Useless;
517 }
518
519 void mark_useless(PhaseIterGVN& igvn);
520
521 void mark_maybe_useful() {
522 _predicate_state = PredicateState::MaybeUseful;
523 }
524
525 bool is_useful() const {
526 return _predicate_state == PredicateState::Useful;
527 }
528
529 void mark_useful() {
530 _predicate_state = PredicateState::Useful;
531 }
532
533 // Return the uncommon trap If projection of this Parse Predicate.
534 ParsePredicateUncommonProj* uncommon_proj() const {
535 return proj_out(0)->as_IfFalse();
536 }
537
538 Node* uncommon_trap() const;
539
540 Node* Ideal(PhaseGVN* phase, bool can_reshape) {
541 return nullptr; // Don't optimize
542 }
543
544 const Type* Value(PhaseGVN* phase) const;
545 NOT_PRODUCT(void dump_spec(outputStream* st) const;)
546 };
547
548 class IfProjNode : public CProjNode {
549 public:
550 IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
551 virtual Node* Identity(PhaseGVN* phase);
552
553 void pin_array_access_nodes(PhaseIterGVN* igvn);
554
555 protected:
556 // Type of If input when this branch is always taken
557 virtual bool always_taken(const TypeTuple* t) const = 0;
558 };
559
560 class IfTrueNode : public IfProjNode {
561 public:
562 IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
563 init_class_id(Class_IfTrue);
564 }
565 virtual int Opcode() const;
566
567 protected:
568 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
569 };
570
571 class IfFalseNode : public IfProjNode {
572 public:
573 IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
574 init_class_id(Class_IfFalse);
575 }
576 virtual int Opcode() const;
577
578 protected:
579 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
580 };
581
582
583 //------------------------------PCTableNode------------------------------------
584 // Build an indirect branch table. Given a control and a table index,
585 // control is passed to the Projection matching the table index. Used to
586 // implement switch statements and exception-handling capabilities.
587 // Undefined behavior if passed-in index is not inside the table.
588 class PCTableNode : public MultiBranchNode {
589 virtual uint hash() const; // Target count; table size
590 virtual bool cmp( const Node &n ) const;
591 virtual uint size_of() const { return sizeof(*this); }
592
593 public:
594 const uint _size; // Number of targets
595
596 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
597 init_class_id(Class_PCTable);
598 init_req(0, ctrl);
599 init_req(1, idx);
600 }
601 virtual int Opcode() const;
602 virtual const Type* Value(PhaseGVN* phase) const;
603 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
604 virtual const Type *bottom_type() const;
605 virtual bool pinned() const { return true; }
606 virtual int required_outcnt() const { return _size; }
607 };
608
609 //------------------------------JumpNode---------------------------------------
610 // Indirect branch. Uses PCTable above to implement a switch statement.
611 // It emits as a table load and local branch.
612 class JumpNode : public PCTableNode {
613 virtual uint size_of() const { return sizeof(*this); }
614 public:
615 float* _probs; // probability of each projection
616 float _fcnt; // total number of times this Jump was executed
617 JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
618 : PCTableNode(control, switch_val, size),
619 _probs(probs), _fcnt(cnt) {
620 init_class_id(Class_Jump);
621 }
622 virtual int Opcode() const;
623 virtual const RegMask& out_RegMask() const;
624 virtual const Node* is_block_proj() const { return this; }
625 };
626
627 class JumpProjNode : public JProjNode {
628 virtual uint hash() const;
629 virtual bool cmp( const Node &n ) const;
630 virtual uint size_of() const { return sizeof(*this); }
631
632 private:
633 const int _dest_bci;
634 const uint _proj_no;
635 const int _switch_val;
636 public:
637 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
638 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
639 init_class_id(Class_JumpProj);
640 }
641
642 virtual int Opcode() const;
643 virtual const Type* bottom_type() const { return Type::CONTROL; }
644 int dest_bci() const { return _dest_bci; }
645 int switch_val() const { return _switch_val; }
646 uint proj_no() const { return _proj_no; }
647 #ifndef PRODUCT
648 virtual void dump_spec(outputStream *st) const;
649 virtual void dump_compact_spec(outputStream *st) const;
650 #endif
651 };
652
653 //------------------------------CatchNode--------------------------------------
654 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by
655 // a just-prior call. Looks like a PCTableNode but emits no code - just the
656 // table. The table lookup and branch is implemented by RethrowNode.
657 class CatchNode : public PCTableNode {
658 public:
659 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
660 init_class_id(Class_Catch);
661 }
662 virtual int Opcode() const;
663 virtual const Type* Value(PhaseGVN* phase) const;
664 };
665
666 // CatchProjNode controls which exception handler is targeted after a call.
667 // It is passed in the bci of the target handler, or no_handler_bci in case
668 // the projection doesn't lead to an exception handler.
669 class CatchProjNode : public CProjNode {
670 virtual uint hash() const;
671 virtual bool cmp( const Node &n ) const;
672 virtual uint size_of() const { return sizeof(*this); }
673
674 private:
675 const int _handler_bci;
676
677 public:
678 enum {
679 fall_through_index = 0, // the fall through projection index
680 catch_all_index = 1, // the projection index for catch-alls
681 no_handler_bci = -1 // the bci for fall through or catch-all projs
682 };
683
684 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
685 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
686 init_class_id(Class_CatchProj);
687 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
688 }
689
690 virtual int Opcode() const;
691 virtual Node* Identity(PhaseGVN* phase);
692 virtual const Type *bottom_type() const { return Type::CONTROL; }
693 int handler_bci() const { return _handler_bci; }
694 bool is_handler_proj() const { return _handler_bci >= 0; }
695 #ifndef PRODUCT
696 virtual void dump_spec(outputStream *st) const;
697 #endif
698 };
699
700
701 //---------------------------------CreateExNode--------------------------------
702 // Helper node to create the exception coming back from a call
703 class CreateExNode : public TypeNode {
704 public:
705 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
706 init_req(0, control);
707 init_req(1, i_o);
708 }
709 virtual int Opcode() const;
710 virtual Node* Identity(PhaseGVN* phase);
711 virtual bool pinned() const { return true; }
712 uint match_edge(uint idx) const { return 0; }
713 virtual uint ideal_reg() const { return Op_RegP; }
714 };
715
716 //------------------------------NeverBranchNode-------------------------------
717 // The never-taken branch. Used to give the appearance of exiting infinite
718 // loops to those algorithms that like all paths to be reachable. Encodes
719 // empty.
720 class NeverBranchNode : public MultiBranchNode {
721 public:
722 NeverBranchNode(Node* ctrl) : MultiBranchNode(1) {
723 init_req(0, ctrl);
724 init_class_id(Class_NeverBranch);
725 }
726 virtual int Opcode() const;
727 virtual bool pinned() const { return true; };
728 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
729 virtual const Type* Value(PhaseGVN* phase) const;
730 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
731 virtual int required_outcnt() const { return 2; }
732 virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const { }
733 virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
734 #ifndef PRODUCT
735 virtual void format( PhaseRegAlloc *, outputStream *st ) const;
736 #endif
737 };
738
739 //------------------------------BlackholeNode----------------------------
740 // Blackhole all arguments. This node would survive through the compiler
741 // the effects on its arguments, and would be finally matched to nothing.
742 class BlackholeNode : public MultiNode {
743 public:
744 BlackholeNode(Node* ctrl) : MultiNode(1) {
745 init_req(TypeFunc::Control, ctrl);
746 init_class_id(Class_Blackhole);
747 }
748 virtual int Opcode() const;
749 virtual uint ideal_reg() const { return 0; } // not matched in the AD file
750 virtual const Type* bottom_type() const { return TypeTuple::MEMBAR; }
751
752 const RegMask &in_RegMask(uint idx) const {
753 // Fake the incoming arguments mask for blackholes: accept all registers
754 // and all stack slots. This would avoid any redundant register moves
755 // for blackhole inputs.
756 return RegMask::All;
757 }
758 #ifndef PRODUCT
759 virtual void format(PhaseRegAlloc* ra, outputStream* st) const;
760 #endif
761 };
762
763
764 #endif // SHARE_OPTO_CFGNODE_HPP