1 /* 2 * Copyright (c) 1997, 2008, 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 // Portions of code courtesy of Clifford Click 26 27 // Optimization - Graph Style 28 29 class Matcher; 30 class Node; 31 class RegionNode; 32 class TypeNode; 33 class PhiNode; 34 class GotoNode; 35 class MultiNode; 36 class MultiBranchNode; 37 class IfNode; 38 class PCTableNode; 39 class JumpNode; 40 class CatchNode; 41 class NeverBranchNode; 42 class ProjNode; 43 class CProjNode; 44 class IfTrueNode; 45 class IfFalseNode; 46 class CatchProjNode; 47 class JProjNode; 48 class JumpProjNode; 49 class SCMemProjNode; 50 class PhaseIdealLoop; 51 52 //------------------------------RegionNode------------------------------------- 53 // The class of RegionNodes, which can be mapped to basic blocks in the 54 // program. Their inputs point to Control sources. PhiNodes (described 55 // below) have an input point to a RegionNode. Merged data inputs to PhiNodes 56 // correspond 1-to-1 with RegionNode inputs. The zero input of a PhiNode is 57 // the RegionNode, and the zero input of the RegionNode is itself. 58 class RegionNode : public Node { 59 public: 60 // Node layout (parallels PhiNode): 61 enum { Region, // Generally points to self. 62 Control // Control arcs are [1..len) 63 }; 64 65 RegionNode( uint required ) : Node(required) { 66 init_class_id(Class_Region); 67 init_req(0,this); 68 } 69 70 Node* is_copy() const { 71 const Node* r = _in[Region]; 72 if (r == NULL) 73 return nonnull_req(); 74 return NULL; // not a copy! 75 } 76 PhiNode* has_phi() const; // returns an arbitrary phi user, or NULL 77 PhiNode* has_unique_phi() const; // returns the unique phi user, or NULL 78 // Is this region node unreachable from root? 79 bool is_unreachable_region(PhaseGVN *phase) const; 80 virtual int Opcode() const; 81 virtual bool pinned() const { return (const Node *)in(0) == this; } 82 virtual bool is_CFG () const { return true; } 83 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash 84 virtual bool depends_only_on_test() const { return false; } 85 virtual const Type *bottom_type() const { return Type::CONTROL; } 86 virtual const Type *Value( PhaseTransform *phase ) const; 87 virtual Node *Identity( PhaseTransform *phase ); 88 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 89 virtual const RegMask &out_RegMask() const; 90 }; 91 92 //------------------------------JProjNode-------------------------------------- 93 // jump projection for node that produces multiple control-flow paths 94 class JProjNode : public ProjNode { 95 public: 96 JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {} 97 virtual int Opcode() const; 98 virtual bool is_CFG() const { return true; } 99 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash 100 virtual const Node* is_block_proj() const { return in(0); } 101 virtual const RegMask& out_RegMask() const; 102 virtual uint ideal_reg() const { return 0; } 103 }; 104 105 //------------------------------PhiNode---------------------------------------- 106 // PhiNodes merge values from different Control paths. Slot 0 points to the 107 // controlling RegionNode. Other slots map 1-for-1 with incoming control flow 108 // paths to the RegionNode. For speed reasons (to avoid another pass) we 109 // can turn PhiNodes into copys in-place by NULL'ing out their RegionNode 110 // input in slot 0. 111 class PhiNode : public TypeNode { 112 const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes. 113 const int _inst_id; // Instance id of the memory slice. 114 const int _inst_index; // Alias index of the instance memory slice. 115 // Array elements references have the same alias_idx but different offset. 116 const int _inst_offset; // Offset of the instance memory slice. 117 // Size is bigger to hold the _adr_type field. 118 virtual uint hash() const; // Check the type 119 virtual uint cmp( const Node &n ) const; 120 virtual uint size_of() const { return sizeof(*this); } 121 122 // Determine if CMoveNode::is_cmove_id can be used at this join point. 123 Node* is_cmove_id(PhaseTransform* phase, int true_path); 124 125 public: 126 // Node layout (parallels RegionNode): 127 enum { Region, // Control input is the Phi's region. 128 Input // Input values are [1..len) 129 }; 130 131 PhiNode( Node *r, const Type *t, const TypePtr* at = NULL, 132 const int iid = TypeOopPtr::InstanceTop, 133 const int iidx = Compile::AliasIdxTop, 134 const int ioffs = Type::OffsetTop ) 135 : TypeNode(t,r->req()), 136 _adr_type(at), 137 _inst_id(iid), 138 _inst_index(iidx), 139 _inst_offset(ioffs) 140 { 141 init_class_id(Class_Phi); 142 init_req(0, r); 143 verify_adr_type(); 144 } 145 // create a new phi with in edges matching r and set (initially) to x 146 static PhiNode* make( Node* r, Node* x ); 147 // extra type arguments override the new phi's bottom_type and adr_type 148 static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL ); 149 // create a new phi with narrowed memory type 150 PhiNode* slice_memory(const TypePtr* adr_type) const; 151 PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const; 152 // like make(r, x), but does not initialize the in edges to x 153 static PhiNode* make_blank( Node* r, Node* x ); 154 155 // Accessors 156 RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; } 157 158 Node* is_copy() const { 159 // The node is a real phi if _in[0] is a Region node. 160 DEBUG_ONLY(const Node* r = _in[Region];) 161 assert(r != NULL && r->is_Region(), "Not valid control"); 162 return NULL; // not a copy! 163 } 164 165 bool is_tripcount() const; 166 167 // Determine a unique non-trivial input, if any. 168 // Ignore casts if it helps. Return NULL on failure. 169 Node* unique_input(PhaseTransform *phase); 170 171 // Check for a simple dead loop. 172 enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; 173 LoopSafety simple_data_loop_check(Node *in) const; 174 // Is it unsafe data loop? It becomes a dead loop if this phi node removed. 175 bool is_unsafe_data_reference(Node *in) const; 176 int is_diamond_phi() const; 177 virtual int Opcode() const; 178 virtual bool pinned() const { return in(0) != 0; } 179 virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; } 180 181 const int inst_id() const { return _inst_id; } 182 const int inst_index() const { return _inst_index; } 183 const int inst_offset() const { return _inst_offset; } 184 bool is_same_inst_field(const Type* tp, int id, int index, int offset) { 185 return type()->basic_type() == tp->basic_type() && 186 inst_id() == id && 187 inst_index() == index && 188 inst_offset() == offset && 189 type()->higher_equal(tp); 190 } 191 192 virtual const Type *Value( PhaseTransform *phase ) const; 193 virtual Node *Identity( PhaseTransform *phase ); 194 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 195 virtual const RegMask &out_RegMask() const; 196 virtual const RegMask &in_RegMask(uint) const; 197 #ifndef PRODUCT 198 virtual void dump_spec(outputStream *st) const; 199 #endif 200 #ifdef ASSERT 201 void verify_adr_type(VectorSet& visited, const TypePtr* at) const; 202 void verify_adr_type(bool recursive = false) const; 203 #else //ASSERT 204 void verify_adr_type(bool recursive = false) const {} 205 #endif //ASSERT 206 }; 207 208 //------------------------------GotoNode--------------------------------------- 209 // GotoNodes perform direct branches. 210 class GotoNode : public Node { 211 public: 212 GotoNode( Node *control ) : Node(control) { 213 init_flags(Flag_is_Goto); 214 } 215 virtual int Opcode() const; 216 virtual bool pinned() const { return true; } 217 virtual bool is_CFG() const { return true; } 218 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash 219 virtual const Node *is_block_proj() const { return this; } 220 virtual bool depends_only_on_test() const { return false; } 221 virtual const Type *bottom_type() const { return Type::CONTROL; } 222 virtual const Type *Value( PhaseTransform *phase ) const; 223 virtual Node *Identity( PhaseTransform *phase ); 224 virtual const RegMask &out_RegMask() const; 225 }; 226 227 //------------------------------CProjNode-------------------------------------- 228 // control projection for node that produces multiple control-flow paths 229 class CProjNode : public ProjNode { 230 public: 231 CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {} 232 virtual int Opcode() const; 233 virtual bool is_CFG() const { return true; } 234 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash 235 virtual const Node *is_block_proj() const { return in(0); } 236 virtual const RegMask &out_RegMask() const; 237 virtual uint ideal_reg() const { return 0; } 238 }; 239 240 //---------------------------MultiBranchNode----------------------------------- 241 // This class defines a MultiBranchNode, a MultiNode which yields multiple 242 // control values. These are distinguished from other types of MultiNodes 243 // which yield multiple values, but control is always and only projection #0. 244 class MultiBranchNode : public MultiNode { 245 public: 246 MultiBranchNode( uint required ) : MultiNode(required) { 247 init_class_id(Class_MultiBranch); 248 } 249 // returns required number of users to be well formed. 250 virtual int required_outcnt() const = 0; 251 }; 252 253 //------------------------------IfNode----------------------------------------- 254 // Output selected Control, based on a boolean test 255 class IfNode : public MultiBranchNode { 256 // Size is bigger to hold the probability field. However, _prob does not 257 // change the semantics so it does not appear in the hash & cmp functions. 258 virtual uint size_of() const { return sizeof(*this); } 259 public: 260 261 // Degrees of branch prediction probability by order of magnitude: 262 // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance. 263 // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N) 264 #define PROB_UNLIKELY_MAG(N) (1e- ## N ## f) 265 #define PROB_LIKELY_MAG(N) (1.0f-PROB_UNLIKELY_MAG(N)) 266 267 // Maximum and minimum branch prediction probabilties 268 // 1 in 1,000,000 (magnitude 6) 269 // 270 // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX 271 // they are used to distinguish different situations: 272 // 273 // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to 274 // very likely (unlikely) but with a concrete possibility of a rare 275 // contrary case. These constants would be used for pinning 276 // measurements, and as measures for assertions that have high 277 // confidence, but some evidence of occasional failure. 278 // 279 // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which 280 // there is no evidence at all that the contrary case has ever occurred. 281 282 #define PROB_NEVER PROB_UNLIKELY_MAG(6) 283 #define PROB_ALWAYS PROB_LIKELY_MAG(6) 284 285 #define PROB_MIN PROB_UNLIKELY_MAG(6) 286 #define PROB_MAX PROB_LIKELY_MAG(6) 287 288 // Static branch prediction probabilities 289 // 1 in 10 (magnitude 1) 290 #define PROB_STATIC_INFREQUENT PROB_UNLIKELY_MAG(1) 291 #define PROB_STATIC_FREQUENT PROB_LIKELY_MAG(1) 292 293 // Fair probability 50/50 294 #define PROB_FAIR (0.5f) 295 296 // Unknown probability sentinel 297 #define PROB_UNKNOWN (-1.0f) 298 299 // Probability "constructors", to distinguish as a probability any manifest 300 // constant without a names 301 #define PROB_LIKELY(x) ((float) (x)) 302 #define PROB_UNLIKELY(x) (1.0f - (float)(x)) 303 304 // Other probabilities in use, but without a unique name, are documented 305 // here for lack of a better place: 306 // 307 // 1 in 1000 probabilities (magnitude 3): 308 // threshold for converting to conditional move 309 // likelihood of null check failure if a null HAS been seen before 310 // likelihood of slow path taken in library calls 311 // 312 // 1 in 10,000 probabilities (magnitude 4): 313 // threshold for making an uncommon trap probability more extreme 314 // threshold for for making a null check implicit 315 // likelihood of needing a gc if eden top moves during an allocation 316 // likelihood of a predicted call failure 317 // 318 // 1 in 100,000 probabilities (magnitude 5): 319 // threshold for ignoring counts when estimating path frequency 320 // likelihood of FP clipping failure 321 // likelihood of catching an exception from a try block 322 // likelihood of null check failure if a null has NOT been seen before 323 // 324 // Magic manifest probabilities such as 0.83, 0.7, ... can be found in 325 // gen_subtype_check() and catch_inline_exceptions(). 326 327 float _prob; // Probability of true path being taken. 328 float _fcnt; // Frequency counter 329 IfNode( Node *control, Node *b, float p, float fcnt ) 330 : MultiBranchNode(2), _prob(p), _fcnt(fcnt) { 331 init_class_id(Class_If); 332 init_req(0,control); 333 init_req(1,b); 334 } 335 virtual int Opcode() const; 336 virtual bool pinned() const { return true; } 337 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; } 338 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 339 virtual const Type *Value( PhaseTransform *phase ) const; 340 virtual int required_outcnt() const { return 2; } 341 virtual const RegMask &out_RegMask() const; 342 void dominated_by(Node* prev_dom, PhaseIterGVN* igvn); 343 int is_range_check(Node* &range, Node* &index, jint &offset); 344 Node* fold_compares(PhaseGVN* phase); 345 static Node* up_one_dom(Node* curr, bool linear_only = false); 346 347 // Takes the type of val and filters it through the test represented 348 // by if_proj and returns a more refined type if one is produced. 349 // Returns NULL is it couldn't improve the type. 350 static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj); 351 352 #ifndef PRODUCT 353 virtual void dump_spec(outputStream *st) const; 354 #endif 355 }; 356 357 class IfTrueNode : public CProjNode { 358 public: 359 IfTrueNode( IfNode *ifnode ) : CProjNode(ifnode,1) { 360 init_class_id(Class_IfTrue); 361 } 362 virtual int Opcode() const; 363 virtual Node *Identity( PhaseTransform *phase ); 364 }; 365 366 class IfFalseNode : public CProjNode { 367 public: 368 IfFalseNode( IfNode *ifnode ) : CProjNode(ifnode,0) { 369 init_class_id(Class_IfFalse); 370 } 371 virtual int Opcode() const; 372 virtual Node *Identity( PhaseTransform *phase ); 373 }; 374 375 376 //------------------------------PCTableNode------------------------------------ 377 // Build an indirect branch table. Given a control and a table index, 378 // control is passed to the Projection matching the table index. Used to 379 // implement switch statements and exception-handling capabilities. 380 // Undefined behavior if passed-in index is not inside the table. 381 class PCTableNode : public MultiBranchNode { 382 virtual uint hash() const; // Target count; table size 383 virtual uint cmp( const Node &n ) const; 384 virtual uint size_of() const { return sizeof(*this); } 385 386 public: 387 const uint _size; // Number of targets 388 389 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) { 390 init_class_id(Class_PCTable); 391 init_req(0, ctrl); 392 init_req(1, idx); 393 } 394 virtual int Opcode() const; 395 virtual const Type *Value( PhaseTransform *phase ) const; 396 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 397 virtual const Type *bottom_type() const; 398 virtual bool pinned() const { return true; } 399 virtual int required_outcnt() const { return _size; } 400 }; 401 402 //------------------------------JumpNode--------------------------------------- 403 // Indirect branch. Uses PCTable above to implement a switch statement. 404 // It emits as a table load and local branch. 405 class JumpNode : public PCTableNode { 406 public: 407 JumpNode( Node* control, Node* switch_val, uint size) : PCTableNode(control, switch_val, size) { 408 init_class_id(Class_Jump); 409 } 410 virtual int Opcode() const; 411 virtual const RegMask& out_RegMask() const; 412 virtual const Node* is_block_proj() const { return this; } 413 }; 414 415 class JumpProjNode : public JProjNode { 416 virtual uint hash() const; 417 virtual uint cmp( const Node &n ) const; 418 virtual uint size_of() const { return sizeof(*this); } 419 420 private: 421 const int _dest_bci; 422 const uint _proj_no; 423 const int _switch_val; 424 public: 425 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val) 426 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) { 427 init_class_id(Class_JumpProj); 428 } 429 430 virtual int Opcode() const; 431 virtual const Type* bottom_type() const { return Type::CONTROL; } 432 int dest_bci() const { return _dest_bci; } 433 int switch_val() const { return _switch_val; } 434 uint proj_no() const { return _proj_no; } 435 #ifndef PRODUCT 436 virtual void dump_spec(outputStream *st) const; 437 #endif 438 }; 439 440 //------------------------------CatchNode-------------------------------------- 441 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by 442 // a just-prior call. Looks like a PCTableNode but emits no code - just the 443 // table. The table lookup and branch is implemented by RethrowNode. 444 class CatchNode : public PCTableNode { 445 public: 446 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){ 447 init_class_id(Class_Catch); 448 } 449 virtual int Opcode() const; 450 virtual const Type *Value( PhaseTransform *phase ) const; 451 }; 452 453 // CatchProjNode controls which exception handler is targetted after a call. 454 // It is passed in the bci of the target handler, or no_handler_bci in case 455 // the projection doesn't lead to an exception handler. 456 class CatchProjNode : public CProjNode { 457 virtual uint hash() const; 458 virtual uint cmp( const Node &n ) const; 459 virtual uint size_of() const { return sizeof(*this); } 460 461 private: 462 const int _handler_bci; 463 464 public: 465 enum { 466 fall_through_index = 0, // the fall through projection index 467 catch_all_index = 1, // the projection index for catch-alls 468 no_handler_bci = -1 // the bci for fall through or catch-all projs 469 }; 470 471 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci) 472 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) { 473 init_class_id(Class_CatchProj); 474 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0"); 475 } 476 477 virtual int Opcode() const; 478 virtual Node *Identity( PhaseTransform *phase ); 479 virtual const Type *bottom_type() const { return Type::CONTROL; } 480 int handler_bci() const { return _handler_bci; } 481 bool is_handler_proj() const { return _handler_bci >= 0; } 482 #ifndef PRODUCT 483 virtual void dump_spec(outputStream *st) const; 484 #endif 485 }; 486 487 488 //---------------------------------CreateExNode-------------------------------- 489 // Helper node to create the exception coming back from a call 490 class CreateExNode : public TypeNode { 491 public: 492 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) { 493 init_req(0, control); 494 init_req(1, i_o); 495 } 496 virtual int Opcode() const; 497 virtual Node *Identity( PhaseTransform *phase ); 498 virtual bool pinned() const { return true; } 499 uint match_edge(uint idx) const { return 0; } 500 virtual uint ideal_reg() const { return Op_RegP; } 501 }; 502 503 //------------------------------NeverBranchNode------------------------------- 504 // The never-taken branch. Used to give the appearance of exiting infinite 505 // loops to those algorithms that like all paths to be reachable. Encodes 506 // empty. 507 class NeverBranchNode : public MultiBranchNode { 508 public: 509 NeverBranchNode( Node *ctrl ) : MultiBranchNode(1) { init_req(0,ctrl); } 510 virtual int Opcode() const; 511 virtual bool pinned() const { return true; }; 512 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; } 513 virtual const Type *Value( PhaseTransform *phase ) const; 514 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 515 virtual int required_outcnt() const { return 2; } 516 virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { } 517 virtual uint size(PhaseRegAlloc *ra_) const { return 0; } 518 #ifndef PRODUCT 519 virtual void format( PhaseRegAlloc *, outputStream *st ) const; 520 #endif 521 };