1 /*
2 * Copyright (c) 1997, 2025, 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).
14 *
15 * You should have received a copy of the GNU General Public License version
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
21 * questions.
22 *
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/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;
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 is_split_through_mergemem_terminating() const;
184
185 void verify_type_stability(const PhaseGVN* phase, const Type* union_of_input_types, const Type* new_type) const NOT_DEBUG_RETURN;
186 bool wait_for_cast_input_igvn(const PhaseIterGVN* igvn) 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 virtual const Type* Value(PhaseGVN* phase) const;
262 virtual Node* Identity(PhaseGVN* phase);
263 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
264 virtual const RegMask &out_RegMask() const;
265 virtual const RegMask &in_RegMask(uint) const;
266 #ifndef PRODUCT
267 virtual void dump_spec(outputStream *st) const;
268 #endif
269 #ifdef ASSERT
270 void verify_adr_type(VectorSet& visited, const TypePtr* at) const;
271 void verify_adr_type(bool recursive = false) const;
272 #else //ASSERT
273 void verify_adr_type(bool recursive = false) const {}
274 #endif //ASSERT
275
276 const TypeTuple* collect_types(PhaseGVN* phase) const;
277 };
278
279 //------------------------------GotoNode---------------------------------------
280 // GotoNodes perform direct branches.
281 class GotoNode : public Node {
282 public:
283 GotoNode( Node *control ) : Node(control) {}
284 virtual int Opcode() const;
285 virtual bool pinned() const { return true; }
286 virtual bool is_CFG() const { return true; }
287 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
288 virtual const Node *is_block_proj() const { return this; }
289 virtual bool depends_only_on_test() const { return false; }
290 virtual const Type *bottom_type() const { return Type::CONTROL; }
291 virtual const Type* Value(PhaseGVN* phase) const;
292 virtual Node* Identity(PhaseGVN* phase);
293 virtual const RegMask &out_RegMask() const;
294 };
295
296 //------------------------------CProjNode--------------------------------------
297 // control projection for node that produces multiple control-flow paths
298 class CProjNode : public ProjNode {
299 public:
300 CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}
301 virtual int Opcode() const;
302 virtual bool is_CFG() const { return true; }
303 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash
304 virtual const Node *is_block_proj() const { return in(0); }
305 virtual const RegMask &out_RegMask() const;
306 virtual uint ideal_reg() const { return 0; }
307 };
308
309 //---------------------------MultiBranchNode-----------------------------------
310 // This class defines a MultiBranchNode, a MultiNode which yields multiple
311 // control values. These are distinguished from other types of MultiNodes
312 // which yield multiple values, but control is always and only projection #0.
313 class MultiBranchNode : public MultiNode {
314 public:
315 MultiBranchNode( uint required ) : MultiNode(required) {
316 init_class_id(Class_MultiBranch);
317 }
318 // returns required number of users to be well formed.
319 virtual uint required_outcnt() const = 0;
320 };
321
322 //------------------------------IfNode-----------------------------------------
323 // Output selected Control, based on a boolean test
324 class IfNode : public MultiBranchNode {
325 public:
326 float _prob; // Probability of true path being taken.
327 float _fcnt; // Frequency counter
328
329 private:
330 AssertionPredicateType _assertion_predicate_type;
331
332 void init_node(Node* control, Node* bol) {
333 init_class_id(Class_If);
334 init_req(0, control);
335 init_req(1, bol);
336 }
337
338 // Size is bigger to hold the probability field. However, _prob does not
339 // change the semantics so it does not appear in the hash & cmp functions.
340 virtual uint size_of() const { return sizeof(*this); }
341
342 // Helper methods for fold_compares
343 bool cmpi_folds(PhaseIterGVN* igvn, bool fold_ne = false);
344 bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);
345 bool has_shared_region(IfProjNode* proj, IfProjNode*& success, IfProjNode*& fail) const;
346 bool has_only_uncommon_traps(IfProjNode* proj, IfProjNode*& success, IfProjNode*& fail, PhaseIterGVN* igvn) const;
347 Node* merge_uncommon_traps(IfProjNode* proj, IfProjNode* success, IfProjNode* fail, PhaseIterGVN* igvn);
348 static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);
349 bool is_cmp_with_loadrange(IfProjNode* proj) const;
350 bool is_null_check(IfProjNode* proj, PhaseIterGVN* igvn) const;
351 bool is_side_effect_free_test(IfProjNode* proj, PhaseIterGVN* igvn) const;
352 static void reroute_side_effect_free_unc(IfProjNode* proj, IfProjNode* dom_proj, PhaseIterGVN* igvn);
353 bool fold_compares_helper(IfProjNode* proj, IfProjNode* success, IfProjNode* fail, PhaseIterGVN* igvn);
354 static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);
355
356 protected:
357 IfProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r) const;
358 Node* Ideal_common(PhaseGVN *phase, bool can_reshape);
359 Node* search_identical(int dist, PhaseIterGVN* igvn);
360
361 Node* simple_subsuming(PhaseIterGVN* igvn);
362
363 public:
364
365 // Degrees of branch prediction probability by order of magnitude:
366 // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.
367 // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)
368 #define PROB_UNLIKELY_MAG(N) (1e- ## N ## f)
369 #define PROB_LIKELY_MAG(N) (1.0f-PROB_UNLIKELY_MAG(N))
370
371 // Maximum and minimum branch prediction probabilties
372 // 1 in 1,000,000 (magnitude 6)
373 //
374 // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX
375 // they are used to distinguish different situations:
376 //
377 // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to
378 // very likely (unlikely) but with a concrete possibility of a rare
379 // contrary case. These constants would be used for pinning
380 // measurements, and as measures for assertions that have high
381 // confidence, but some evidence of occasional failure.
382 //
383 // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which
384 // there is no evidence at all that the contrary case has ever occurred.
385
386 #define PROB_NEVER PROB_UNLIKELY_MAG(6)
387 #define PROB_ALWAYS PROB_LIKELY_MAG(6)
388
389 #define PROB_MIN PROB_UNLIKELY_MAG(6)
390 #define PROB_MAX PROB_LIKELY_MAG(6)
391
392 // Static branch prediction probabilities
393 // 1 in 10 (magnitude 1)
394 #define PROB_STATIC_INFREQUENT PROB_UNLIKELY_MAG(1)
395 #define PROB_STATIC_FREQUENT PROB_LIKELY_MAG(1)
396
397 // Fair probability 50/50
398 #define PROB_FAIR (0.5f)
399
400 // Unknown probability sentinel
401 #define PROB_UNKNOWN (-1.0f)
402
403 // Probability "constructors", to distinguish as a probability any manifest
404 // constant without a names
405 #define PROB_LIKELY(x) ((float) (x))
406 #define PROB_UNLIKELY(x) (1.0f - (float)(x))
407
408 // Other probabilities in use, but without a unique name, are documented
409 // here for lack of a better place:
410 //
411 // 1 in 1000 probabilities (magnitude 3):
412 // threshold for converting to conditional move
413 // likelihood of null check failure if a null HAS been seen before
414 // likelihood of slow path taken in library calls
415 //
416 // 1 in 10,000 probabilities (magnitude 4):
417 // threshold for making an uncommon trap probability more extreme
418 // threshold for for making a null check implicit
419 // likelihood of needing a gc if eden top moves during an allocation
420 // likelihood of a predicted call failure
421 //
422 // 1 in 100,000 probabilities (magnitude 5):
423 // threshold for ignoring counts when estimating path frequency
424 // likelihood of FP clipping failure
425 // likelihood of catching an exception from a try block
426 // likelihood of null check failure if a null has NOT been seen before
427 //
428 // Magic manifest probabilities such as 0.83, 0.7, ... can be found in
429 // gen_subtype_check() and catch_inline_exceptions().
430
431 IfNode(Node* control, Node* bol, float p, float fcnt);
432 IfNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type);
433
434 static IfNode* make_with_same_profile(IfNode* if_node_profile, Node* ctrl, Node* bol);
435
436 IfTrueNode* true_proj() const {
437 return proj_out(true)->as_IfTrue();
438 }
439
440 IfTrueNode* true_proj_or_null() const {
441 ProjNode* true_proj = proj_out_or_null(true);
442 return true_proj == nullptr ? nullptr : true_proj->as_IfTrue();
443 }
444
445 IfFalseNode* false_proj() const {
446 return proj_out(false)->as_IfFalse();
447 }
448
449 IfFalseNode* false_proj_or_null() const {
450 ProjNode* false_proj = proj_out_or_null(false);
451 return false_proj == nullptr ? nullptr : false_proj->as_IfFalse();
452 }
453
454 virtual int Opcode() const;
455 virtual bool pinned() const { return true; }
456 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
457 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
458 virtual const Type* Value(PhaseGVN* phase) const;
459 virtual uint required_outcnt() const { return 2; }
460 virtual const RegMask &out_RegMask() const;
461 Node* fold_compares(PhaseIterGVN* phase);
462 static Node* up_one_dom(Node* curr, bool linear_only = false);
463 bool is_zero_trip_guard() const;
464 Node* dominated_by(Node* prev_dom, PhaseIterGVN* igvn, bool pin_array_access_nodes);
465 ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call, Deoptimization::DeoptReason reason = Deoptimization::Reason_none) const;
466
467 // Takes the type of val and filters it through the test represented
468 // by if_proj and returns a more refined type if one is produced.
469 // Returns null is it couldn't improve the type.
470 static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);
471
472 AssertionPredicateType assertion_predicate_type() const {
473 return _assertion_predicate_type;
474 }
475
476 #ifndef PRODUCT
477 virtual void dump_spec(outputStream *st) const;
478 #endif
479
480 bool same_condition(const Node* dom, PhaseIterGVN* igvn) const;
481 };
482
483 class RangeCheckNode : public IfNode {
484 private:
485 int is_range_check(Node*& range, Node*& index, jint& offset);
486
487 public:
488 RangeCheckNode(Node* control, Node* bol, float p, float fcnt) : IfNode(control, bol, p, fcnt) {
489 init_class_id(Class_RangeCheck);
490 }
491
492 RangeCheckNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type)
493 : IfNode(control, bol, p, fcnt, assertion_predicate_type) {
494 init_class_id(Class_RangeCheck);
495 }
496
497 virtual int Opcode() const;
498 virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
499 };
500
501 // Special node that denotes a Parse Predicate added during parsing. A Parse Predicate serves as placeholder to later
502 // create Regular Predicates (Runtime Predicates with possible Assertion Predicates) above it. Together they form a
503 // Predicate Block. The Parse Predicate and Regular Predicates share the same uncommon trap.
504 // There are three kinds of Parse Predicates:
505 // Loop Parse Predicate, Profiled Loop Parse Predicate (both used by Loop Predication), and Loop Limit Check Parse
506 // Predicate (used for integer overflow checks when creating a counted loop).
507 // More information about predicates can be found in loopPredicate.cpp.
508 class ParsePredicateNode : public IfNode {
509 Deoptimization::DeoptReason _deopt_reason;
510
511 // When a Parse Predicate loses its connection to a loop head, it will be marked useless by
512 // EliminateUselessPredicates and cleaned up by Value(). It can also become useless when cloning it to both loops
513 // during Loop Multiversioning - we no longer use the old version.
514 PredicateState _predicate_state;
515 public:
516 ParsePredicateNode(Node* control, Deoptimization::DeoptReason deopt_reason, PhaseGVN* gvn);
517 virtual int Opcode() const;
518 virtual uint size_of() const { return sizeof(*this); }
519
520 Deoptimization::DeoptReason deopt_reason() const {
521 return _deopt_reason;
522 }
523
524 bool is_useless() const {
525 return _predicate_state == PredicateState::Useless;
526 }
527
528 void mark_useless(PhaseIterGVN& igvn);
529
530 void mark_maybe_useful() {
531 _predicate_state = PredicateState::MaybeUseful;
532 }
533
534 bool is_useful() const {
535 return _predicate_state == PredicateState::Useful;
536 }
537
538 void mark_useful() {
539 _predicate_state = PredicateState::Useful;
540 }
541
542 // Return the uncommon trap If projection of this Parse Predicate.
543 ParsePredicateUncommonProj* uncommon_proj() const {
544 return false_proj();
545 }
546
547 Node* uncommon_trap() const;
548
549 Node* Ideal(PhaseGVN* phase, bool can_reshape) {
550 return nullptr; // Don't optimize
551 }
552
553 const Type* Value(PhaseGVN* phase) const;
554 NOT_PRODUCT(void dump_spec(outputStream* st) const;)
555 };
556
557 class IfProjNode : public CProjNode {
558 public:
559 IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}
560 virtual Node* Identity(PhaseGVN* phase);
561
562 // Return the other IfProj node.
563 IfProjNode* other_if_proj() const {
564 return in(0)->as_If()->proj_out(1 - _con)->as_IfProj();
565 }
566
567 void pin_array_access_nodes(PhaseIterGVN* igvn);
568
569 protected:
570 // Type of If input when this branch is always taken
571 virtual bool always_taken(const TypeTuple* t) const = 0;
572 };
573
574 class IfTrueNode : public IfProjNode {
575 public:
576 IfTrueNode( IfNode *ifnode ) : IfProjNode(ifnode,1) {
577 init_class_id(Class_IfTrue);
578 }
579 virtual int Opcode() const;
580
581 protected:
582 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }
583 };
584
585 class IfFalseNode : public IfProjNode {
586 public:
587 IfFalseNode( IfNode *ifnode ) : IfProjNode(ifnode,0) {
588 init_class_id(Class_IfFalse);
589 }
590 virtual int Opcode() const;
591
592 protected:
593 virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }
594 };
595
596
597 //------------------------------PCTableNode------------------------------------
598 // Build an indirect branch table. Given a control and a table index,
599 // control is passed to the Projection matching the table index. Used to
600 // implement switch statements and exception-handling capabilities.
601 // Undefined behavior if passed-in index is not inside the table.
602 class PCTableNode : public MultiBranchNode {
603 virtual uint hash() const; // Target count; table size
604 virtual bool cmp( const Node &n ) const;
605 virtual uint size_of() const { return sizeof(*this); }
606
607 public:
608 const uint _size; // Number of targets
609
610 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {
611 init_class_id(Class_PCTable);
612 init_req(0, ctrl);
613 init_req(1, idx);
614 }
615 virtual int Opcode() const;
616 virtual const Type* Value(PhaseGVN* phase) const;
617 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
618 virtual const Type *bottom_type() const;
619 virtual bool pinned() const { return true; }
620 virtual uint required_outcnt() const { return _size; }
621 };
622
623 //------------------------------JumpNode---------------------------------------
624 // Indirect branch. Uses PCTable above to implement a switch statement.
625 // It emits as a table load and local branch.
626 class JumpNode : public PCTableNode {
627 virtual uint size_of() const { return sizeof(*this); }
628 public:
629 float* _probs; // probability of each projection
630 float _fcnt; // total number of times this Jump was executed
631 JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)
632 : PCTableNode(control, switch_val, size),
633 _probs(probs), _fcnt(cnt) {
634 init_class_id(Class_Jump);
635 }
636 virtual int Opcode() const;
637 virtual const RegMask& out_RegMask() const;
638 virtual const Node* is_block_proj() const { return this; }
639 };
640
641 class JumpProjNode : public JProjNode {
642 virtual uint hash() const;
643 virtual bool cmp( const Node &n ) const;
644 virtual uint size_of() const { return sizeof(*this); }
645
646 private:
647 const int _dest_bci;
648 const uint _proj_no;
649 const int _switch_val;
650 public:
651 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)
652 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {
653 init_class_id(Class_JumpProj);
654 }
655
656 virtual int Opcode() const;
657 virtual const Type* bottom_type() const { return Type::CONTROL; }
658 int dest_bci() const { return _dest_bci; }
659 int switch_val() const { return _switch_val; }
660 uint proj_no() const { return _proj_no; }
661 #ifndef PRODUCT
662 virtual void dump_spec(outputStream *st) const;
663 virtual void dump_compact_spec(outputStream *st) const;
664 #endif
665 };
666
667 //------------------------------CatchNode--------------------------------------
668 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by
669 // a just-prior call. Looks like a PCTableNode but emits no code - just the
670 // table. The table lookup and branch is implemented by RethrowNode.
671 class CatchNode : public PCTableNode {
672 public:
673 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){
674 init_class_id(Class_Catch);
675 }
676 virtual int Opcode() const;
677 virtual const Type* Value(PhaseGVN* phase) const;
678 };
679
680 // CatchProjNode controls which exception handler is targeted after a call.
681 // It is passed in the bci of the target handler, or no_handler_bci in case
682 // the projection doesn't lead to an exception handler.
683 class CatchProjNode : public CProjNode {
684 virtual uint hash() const;
685 virtual bool cmp( const Node &n ) const;
686 virtual uint size_of() const { return sizeof(*this); }
687
688 private:
689 const int _handler_bci;
690
691 public:
692 enum {
693 fall_through_index = 0, // the fall through projection index
694 catch_all_index = 1, // the projection index for catch-alls
695 no_handler_bci = -1 // the bci for fall through or catch-all projs
696 };
697
698 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)
699 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {
700 init_class_id(Class_CatchProj);
701 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");
702 }
703
704 virtual int Opcode() const;
705 virtual Node* Identity(PhaseGVN* phase);
706 virtual const Type *bottom_type() const { return Type::CONTROL; }
707 int handler_bci() const { return _handler_bci; }
708 bool is_handler_proj() const { return _handler_bci >= 0; }
709 #ifndef PRODUCT
710 virtual void dump_spec(outputStream *st) const;
711 #endif
712 };
713
714
715 //---------------------------------CreateExNode--------------------------------
716 // Helper node to create the exception coming back from a call
717 class CreateExNode : public TypeNode {
718 public:
719 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {
720 init_req(0, control);
721 init_req(1, i_o);
722 }
723 virtual int Opcode() const;
724 virtual Node* Identity(PhaseGVN* phase);
725 virtual bool pinned() const { return true; }
726 uint match_edge(uint idx) const { return 0; }
727 virtual uint ideal_reg() const { return Op_RegP; }
728 };
729
730 //------------------------------NeverBranchNode-------------------------------
731 // The never-taken branch. Used to give the appearance of exiting infinite
732 // loops to those algorithms that like all paths to be reachable. Encodes
733 // empty.
734 class NeverBranchNode : public MultiBranchNode {
735 public:
736 NeverBranchNode(Node* ctrl) : MultiBranchNode(1) {
737 init_req(0, ctrl);
738 init_class_id(Class_NeverBranch);
739 }
740 virtual int Opcode() const;
741 virtual bool pinned() const { return true; };
742 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }
743 virtual const Type* Value(PhaseGVN* phase) const;
744 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
745 virtual uint required_outcnt() const { return 2; }
746 virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const { }
747 virtual uint size(PhaseRegAlloc *ra_) const { return 0; }
748 #ifndef PRODUCT
749 virtual void format( PhaseRegAlloc *, outputStream *st ) const;
750 #endif
751 };
752
753 //------------------------------BlackholeNode----------------------------
754 // Blackhole all arguments. This node would survive through the compiler
755 // the effects on its arguments, and would be finally matched to nothing.
756 class BlackholeNode : public MultiNode {
757 public:
758 BlackholeNode(Node* ctrl) : MultiNode(1) {
759 init_req(TypeFunc::Control, ctrl);
760 }
761 virtual int Opcode() const;
762 virtual uint ideal_reg() const { return 0; } // not matched in the AD file
763 virtual const Type* bottom_type() const { return TypeTuple::MEMBAR; }
764 virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
765
766 const RegMask &in_RegMask(uint idx) const {
767 // Fake the incoming arguments mask for blackholes: accept all registers
768 // and all stack slots. This would avoid any redundant register moves
769 // for blackhole inputs.
770 return RegMask::ALL;
771 }
772 #ifndef PRODUCT
773 virtual void format(PhaseRegAlloc* ra, outputStream* st) const;
774 #endif
775 };
776
777
778 #endif // SHARE_OPTO_CFGNODE_HPP