1 /*
2 * Copyright (c) 1997, 2024, 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
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7 * published by the Free Software Foundation.
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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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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 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 enum class AssertionPredicateType;
61
62 // The success projection of a Parse Predicate is always an IfTrueNode and the uncommon projection an IfFalseNode
63 typedef IfTrueNode ParsePredicateSuccessProj;
64 typedef IfFalseNode ParsePredicateUncommonProj;
65
66 //------------------------------RegionNode-------------------------------------
67 // The class of RegionNodes, which can be mapped to basic blocks in the
68 // program. Their inputs point to Control sources. PhiNodes (described
69 // below) have an input point to a RegionNode. Merged data inputs to PhiNodes
70 // correspond 1-to-1 with RegionNode inputs. The zero input of a PhiNode is
71 // the RegionNode, and the zero input of the RegionNode is itself.
72 class RegionNode : public Node {
73 public:
74 enum LoopStatus {
75 // No guarantee: the region may be an irreducible loop entry, thus we have to
76 // be careful when removing entry control to it.
77 MaybeIrreducibleEntry,
78 // Limited guarantee: this region may be (nested) inside an irreducible loop,
79 // but it will never be an irreducible loop entry.
80 NeverIrreducibleEntry,
81 // Strong guarantee: this region is not (nested) inside an irreducible loop.
82 Reducible,
83 };
84
85 private:
86 bool _is_unreachable_region;
87 LoopStatus _loop_status;
88
89 bool is_possible_unsafe_loop(const PhaseGVN* phase) const;
90 bool is_unreachable_from_root(const PhaseGVN* phase) const;
91 public:
92 // Node layout (parallels PhiNode):
93 enum { Region, // Generally points to self.
94 Control // Control arcs are [1..len)
95 };
96
97 RegionNode(uint required)
98 : Node(required),
99 _is_unreachable_region(false),
100 _loop_status(LoopStatus::NeverIrreducibleEntry)
101 {
102 init_class_id(Class_Region);
103 init_req(0, this);
104 }
105
106 Node* is_copy() const {
107 const Node* r = _in[Region];
108 if (r == nullptr)
109 return nonnull_req();
110 return nullptr; // not a copy!
111 }
112 PhiNode* has_phi() const; // returns an arbitrary phi user, or null
113 PhiNode* has_unique_phi() const; // returns the unique phi user, or null
114 // Is this region node unreachable from root?
115 bool is_unreachable_region(const PhaseGVN* phase);
116 #ifdef ASSERT
117 bool is_in_infinite_subgraph();
118 static bool are_all_nodes_in_infinite_subgraph(Unique_Node_List& worklist);
119 #endif //ASSERT
120 LoopStatus loop_status() const { return _loop_status; };
121 void set_loop_status(LoopStatus status);
122 DEBUG_ONLY(void verify_can_be_irreducible_entry() const;)
123
124 virtual int Opcode() const;
125 virtual uint size_of() const { return sizeof(*this); }
126 virtual bool pinned() const { return (const Node*)in(0) == this; }
127 virtual bool is_CFG() const { return true; }
128 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
129 virtual bool depends_only_on_test() const { return false; }
130 virtual const Type* bottom_type() const { return Type::CONTROL; }
131 virtual const Type* Value(PhaseGVN* phase) const;
132 virtual Node* Identity(PhaseGVN* phase);
133 virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
134 void remove_unreachable_subgraph(PhaseIterGVN* igvn);
135 virtual const RegMask &out_RegMask() const;
136 bool is_diamond() const;
137 void try_clean_mem_phis(PhaseIterGVN* phase);
138 bool optimize_trichotomy(PhaseIterGVN* igvn);
139 NOT_PRODUCT(virtual void dump_spec(outputStream* st) const;)
140 };
141
142 //------------------------------JProjNode--------------------------------------
143 // jump projection for node that produces multiple control-flow paths
144 class JProjNode : public ProjNode {
145 public:
146 JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}
147 virtual int Opcode() const;
148 virtual bool is_CFG() const { return true; }
149 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
150 virtual const Node* is_block_proj() const { return in(0); }
151 virtual const RegMask& out_RegMask() const;
152 virtual uint ideal_reg() const { return 0; }
153 };
154
155 //------------------------------PhiNode----------------------------------------
156 // PhiNodes merge values from different Control paths. Slot 0 points to the
157 // controlling RegionNode. Other slots map 1-for-1 with incoming control flow
158 // paths to the RegionNode.
159 class PhiNode : public TypeNode {
160 friend class PhaseRenumberLive;
161
162 const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.
163 // The following fields are only used for data PhiNodes to indicate
164 // that the PhiNode represents the value of a known instance field.
165 int _inst_mem_id; // Instance memory id (node index of the memory Phi)
166 int _inst_id; // Instance id of the memory slice.
167 const int _inst_index; // Alias index of the instance memory slice.
168 // Array elements references have the same alias_idx but different offset.
169 const int _inst_offset; // Offset of the instance memory slice.
170 // Size is bigger to hold the _adr_type field.
171 virtual uint hash() const; // Check the type
172 virtual bool cmp( const Node &n ) const;
173 virtual uint size_of() const { return sizeof(*this); }
174
175 // Determine if CMoveNode::is_cmove_id can be used at this join point.
176 Node* is_cmove_id(PhaseTransform* phase, int true_path);
177 bool wait_for_region_igvn(PhaseGVN* phase);
178 bool is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase);
179
180 static Node* clone_through_phi(Node* root_phi, const Type* t, uint c, PhaseIterGVN* igvn);
181 static Node* merge_through_phi(Node* root_phi, PhaseIterGVN* igvn);
182
183 bool must_wait_for_region_in_irreducible_loop(PhaseGVN* phase) const;
184
185 bool can_push_inline_types_down(PhaseGVN* phase, bool can_reshape, ciInlineKlass*& inline_klass);
186 InlineTypeNode* push_inline_types_down(PhaseGVN* phase, bool can_reshape, ciInlineKlass* inline_klass);
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 NOT_PRODUCT(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 NOT_PRODUCT(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, BoolNode* 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 #ifndef PRODUCT
464 AssertionPredicateType assertion_predicate_type() const {
465 return _assertion_predicate_type;
466 }
467
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 #ifndef PRODUCT
484 RangeCheckNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type)
485 : IfNode(control, bol, p, fcnt, assertion_predicate_type) {
486 init_class_id(Class_RangeCheck);
487 }
488 #endif // NOT PRODUCT
489
490 virtual int Opcode() const;
491 virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
492 };
493
494 // Special node that denotes a Parse Predicate added during parsing. A Parse Predicate serves as placeholder to later
495 // create Regular Predicates (Runtime Predicates with possible Assertion Predicates) above it. Together they form a
496 // Predicate Block. The Parse Predicate and Regular Predicates share the same uncommon trap.
497 // There are three kinds of Parse Predicates:
498 // Loop Parse Predicate, Profiled Loop Parse Predicate (both used by Loop Predication), and Loop Limit Check Parse
499 // Predicate (used for integer overflow checks when creating a counted loop).
500 // More information about predicates can be found in loopPredicate.cpp.
501 class ParsePredicateNode : public IfNode {
502 Deoptimization::DeoptReason _deopt_reason;
503 bool _useless; // If the associated loop dies, this parse predicate becomes useless and can be cleaned up by Value().
504 public:
505 ParsePredicateNode(Node* control, Deoptimization::DeoptReason deopt_reason, PhaseGVN* gvn);
506 virtual int Opcode() const;
507 virtual uint size_of() const { return sizeof(*this); }
508
509 Deoptimization::DeoptReason deopt_reason() const {
510 return _deopt_reason;
511 }
512
513 bool is_useless() const {
514 return _useless;
515 }
516
517 void mark_useless() {
518 _useless = true;
519 }
520
521 void mark_useful() {
522 _useless = false;
523 }
524
525 // Return the uncommon trap If projection of this Parse Predicate.
526 ParsePredicateUncommonProj* uncommon_proj() const {
527 return proj_out(0)->as_IfFalse();
528 }
529
530 Node* uncommon_trap() const;
531
532 Node* Ideal(PhaseGVN* phase, bool can_reshape) {
533 return nullptr; // Don't optimize
534 }
535
536 const Type* Value(PhaseGVN* phase) const;
537 NOT_PRODUCT(void dump_spec(outputStream* st) const;)
538 };
539
540 class IfProjNode : public CProjNode {
541 public:
542 IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
543 virtual Node* Identity(PhaseGVN* phase);
544
545 void pin_array_access_nodes(PhaseIterGVN* igvn);
546
547 protected:
548 // Type of If input when this branch is always taken
549 virtual bool always_taken(const TypeTuple* t) const = 0;
550 };
551
552 class IfTrueNode : public IfProjNode {
553 public:
554 IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
555 init_class_id(Class_IfTrue);
556 }
557 virtual int Opcode() const;
558
559 protected:
560 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
561 };
562
563 class IfFalseNode : public IfProjNode {
564 public:
565 IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
566 init_class_id(Class_IfFalse);
567 }
568 virtual int Opcode() const;
569
570 protected:
571 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
572 };
573
574
575 //------------------------------PCTableNode------------------------------------
576 // Build an indirect branch table. Given a control and a table index,
577 // control is passed to the Projection matching the table index. Used to
578 // implement switch statements and exception-handling capabilities.
579 // Undefined behavior if passed-in index is not inside the table.
580 class PCTableNode : public MultiBranchNode {
581 virtual uint hash() const; // Target count; table size
582 virtual bool cmp( const Node &n ) const;
583 virtual uint size_of() const { return sizeof(*this); }
584
585 public:
586 const uint _size; // Number of targets
587
588 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
589 init_class_id(Class_PCTable);
590 init_req(0, ctrl);
591 init_req(1, idx);
592 }
593 virtual int Opcode() const;
594 virtual const Type* Value(PhaseGVN* phase) const;
595 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
596 virtual const Type *bottom_type() const;
597 virtual bool pinned() const { return true; }
598 virtual int required_outcnt() const { return _size; }
599 };
600
601 //------------------------------JumpNode---------------------------------------
602 // Indirect branch. Uses PCTable above to implement a switch statement.
603 // It emits as a table load and local branch.
604 class JumpNode : public PCTableNode {
605 virtual uint size_of() const { return sizeof(*this); }
606 public:
607 float* _probs; // probability of each projection
608 float _fcnt; // total number of times this Jump was executed
609 JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
610 : PCTableNode(control, switch_val, size),
611 _probs(probs), _fcnt(cnt) {
612 init_class_id(Class_Jump);
613 }
614 virtual int Opcode() const;
615 virtual const RegMask& out_RegMask() const;
616 virtual const Node* is_block_proj() const { return this; }
617 };
618
619 class JumpProjNode : public JProjNode {
620 virtual uint hash() const;
621 virtual bool cmp( const Node &n ) const;
622 virtual uint size_of() const { return sizeof(*this); }
623
624 private:
625 const int _dest_bci;
626 const uint _proj_no;
627 const int _switch_val;
628 public:
629 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
630 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
631 init_class_id(Class_JumpProj);
632 }
633
634 virtual int Opcode() const;
635 virtual const Type* bottom_type() const { return Type::CONTROL; }
636 int dest_bci() const { return _dest_bci; }
637 int switch_val() const { return _switch_val; }
638 uint proj_no() const { return _proj_no; }
639 #ifndef PRODUCT
640 virtual void dump_spec(outputStream *st) const;
641 virtual void dump_compact_spec(outputStream *st) const;
642 #endif
643 };
644
645 //------------------------------CatchNode--------------------------------------
646 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by
647 // a just-prior call. Looks like a PCTableNode but emits no code - just the
648 // table. The table lookup and branch is implemented by RethrowNode.
649 class CatchNode : public PCTableNode {
650 public:
651 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
652 init_class_id(Class_Catch);
653 }
654 virtual int Opcode() const;
655 virtual const Type* Value(PhaseGVN* phase) const;
656 };
657
658 // CatchProjNode controls which exception handler is targeted after a call.
659 // It is passed in the bci of the target handler, or no_handler_bci in case
660 // the projection doesn't lead to an exception handler.
661 class CatchProjNode : public CProjNode {
662 virtual uint hash() const;
663 virtual bool cmp( const Node &n ) const;
664 virtual uint size_of() const { return sizeof(*this); }
665
666 private:
667 const int _handler_bci;
668
669 public:
670 enum {
671 fall_through_index = 0, // the fall through projection index
672 catch_all_index = 1, // the projection index for catch-alls
673 no_handler_bci = -1 // the bci for fall through or catch-all projs
674 };
675
676 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
677 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
678 init_class_id(Class_CatchProj);
679 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
680 }
681
682 virtual int Opcode() const;
683 virtual Node* Identity(PhaseGVN* phase);
684 virtual const Type *bottom_type() const { return Type::CONTROL; }
685 int handler_bci() const { return _handler_bci; }
686 bool is_handler_proj() const { return _handler_bci >= 0; }
687 #ifndef PRODUCT
688 virtual void dump_spec(outputStream *st) const;
689 #endif
690 };
691
692
693 //---------------------------------CreateExNode--------------------------------
694 // Helper node to create the exception coming back from a call
695 class CreateExNode : public TypeNode {
696 public:
697 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
698 init_req(0, control);
699 init_req(1, i_o);
700 }
701 virtual int Opcode() const;
702 virtual Node* Identity(PhaseGVN* phase);
703 virtual bool pinned() const { return true; }
704 uint match_edge(uint idx) const { return 0; }
705 virtual uint ideal_reg() const { return Op_RegP; }
706 };
707
708 //------------------------------NeverBranchNode-------------------------------
709 // The never-taken branch. Used to give the appearance of exiting infinite
710 // loops to those algorithms that like all paths to be reachable. Encodes
711 // empty.
712 class NeverBranchNode : public MultiBranchNode {
713 public:
714 NeverBranchNode(Node* ctrl) : MultiBranchNode(1) {
715 init_req(0, ctrl);
716 init_class_id(Class_NeverBranch);
717 }
718 virtual int Opcode() const;
719 virtual bool pinned() const { return true; };
720 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
721 virtual const Type* Value(PhaseGVN* phase) const;
722 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
723 virtual int required_outcnt() const { return 2; }
724 virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const { }
725 virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
726 #ifndef PRODUCT
727 virtual void format( PhaseRegAlloc *, outputStream *st ) const;
728 #endif
729 };
730
731 //------------------------------BlackholeNode----------------------------
732 // Blackhole all arguments. This node would survive through the compiler
733 // the effects on its arguments, and would be finally matched to nothing.
734 class BlackholeNode : public MultiNode {
735 public:
736 BlackholeNode(Node* ctrl) : MultiNode(1) {
737 init_req(TypeFunc::Control, ctrl);
738 init_class_id(Class_Blackhole);
739 }
740 virtual int Opcode() const;
741 virtual uint ideal_reg() const { return 0; } // not matched in the AD file
742 virtual const Type* bottom_type() const { return TypeTuple::MEMBAR; }
743
744 const RegMask &in_RegMask(uint idx) const {
745 // Fake the incoming arguments mask for blackholes: accept all registers
746 // and all stack slots. This would avoid any redundant register moves
747 // for blackhole inputs.
748 return RegMask::All;
749 }
750 #ifndef PRODUCT
751 virtual void format(PhaseRegAlloc* ra, outputStream* st) const;
752 #endif
753 };
754
755
756 #endif // SHARE_OPTO_CFGNODE_HPP