AliasAnalysis.h revision 8e0d1c03ca7fd86e6879b4e37d0d7f0e982feef6
1//===- llvm/Analysis/AliasAnalysis.h - Alias Analysis Interface -*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the generic AliasAnalysis interface, which is used as the 11// common interface used by all clients of alias analysis information, and 12// implemented by all alias analysis implementations. Mod/Ref information is 13// also captured by this interface. 14// 15// Implementations of this interface must implement the various virtual methods, 16// which automatically provides functionality for the entire suite of client 17// APIs. 18// 19// This API identifies memory regions with the Location class. The pointer 20// component specifies the base memory address of the region. The Size specifies 21// the maximum size (in address units) of the memory region, or UnknownSize if 22// the size is not known. The TBAA tag identifies the "type" of the memory 23// reference; see the TypeBasedAliasAnalysis class for details. 24// 25// Some non-obvious details include: 26// - Pointers that point to two completely different objects in memory never 27// alias, regardless of the value of the Size component. 28// - NoAlias doesn't imply inequal pointers. The most obvious example of this 29// is two pointers to constant memory. Even if they are equal, constant 30// memory is never stored to, so there will never be any dependencies. 31// In this and other situations, the pointers may be both NoAlias and 32// MustAlias at the same time. The current API can only return one result, 33// though this is rarely a problem in practice. 34// 35//===----------------------------------------------------------------------===// 36 37#ifndef LLVM_ANALYSIS_ALIAS_ANALYSIS_H 38#define LLVM_ANALYSIS_ALIAS_ANALYSIS_H 39 40#include "llvm/Support/CallSite.h" 41#include "llvm/ADT/DenseMap.h" 42 43namespace llvm { 44 45class LoadInst; 46class StoreInst; 47class VAArgInst; 48class TargetData; 49class TargetLibraryInfo; 50class Pass; 51class AnalysisUsage; 52class MemTransferInst; 53class MemIntrinsic; 54class DominatorTree; 55 56class AliasAnalysis { 57protected: 58 const TargetData *TD; 59 const TargetLibraryInfo *TLI; 60 61private: 62 AliasAnalysis *AA; // Previous Alias Analysis to chain to. 63 64protected: 65 /// InitializeAliasAnalysis - Subclasses must call this method to initialize 66 /// the AliasAnalysis interface before any other methods are called. This is 67 /// typically called by the run* methods of these subclasses. This may be 68 /// called multiple times. 69 /// 70 void InitializeAliasAnalysis(Pass *P); 71 72 /// getAnalysisUsage - All alias analysis implementations should invoke this 73 /// directly (using AliasAnalysis::getAnalysisUsage(AU)). 74 virtual void getAnalysisUsage(AnalysisUsage &AU) const; 75 76public: 77 static char ID; // Class identification, replacement for typeinfo 78 AliasAnalysis() : TD(0), TLI(0), AA(0) {} 79 virtual ~AliasAnalysis(); // We want to be subclassed 80 81 /// UnknownSize - This is a special value which can be used with the 82 /// size arguments in alias queries to indicate that the caller does not 83 /// know the sizes of the potential memory references. 84 static uint64_t const UnknownSize = ~UINT64_C(0); 85 86 /// getTargetData - Return a pointer to the current TargetData object, or 87 /// null if no TargetData object is available. 88 /// 89 const TargetData *getTargetData() const { return TD; } 90 91 /// getTargetLibraryInfo - Return a pointer to the current TargetLibraryInfo 92 /// object, or null if no TargetLibraryInfo object is available. 93 /// 94 const TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; } 95 96 /// getTypeStoreSize - Return the TargetData store size for the given type, 97 /// if known, or a conservative value otherwise. 98 /// 99 uint64_t getTypeStoreSize(Type *Ty); 100 101 //===--------------------------------------------------------------------===// 102 /// Alias Queries... 103 /// 104 105 /// Location - A description of a memory location. 106 struct Location { 107 /// Ptr - The address of the start of the location. 108 const Value *Ptr; 109 /// Size - The maximum size of the location, in address-units, or 110 /// UnknownSize if the size is not known. Note that an unknown size does 111 /// not mean the pointer aliases the entire virtual address space, because 112 /// there are restrictions on stepping out of one object and into another. 113 /// See http://llvm.org/docs/LangRef.html#pointeraliasing 114 uint64_t Size; 115 /// TBAATag - The metadata node which describes the TBAA type of 116 /// the location, or null if there is no known unique tag. 117 const MDNode *TBAATag; 118 119 explicit Location(const Value *P = 0, uint64_t S = UnknownSize, 120 const MDNode *N = 0) 121 : Ptr(P), Size(S), TBAATag(N) {} 122 123 Location getWithNewPtr(const Value *NewPtr) const { 124 Location Copy(*this); 125 Copy.Ptr = NewPtr; 126 return Copy; 127 } 128 129 Location getWithNewSize(uint64_t NewSize) const { 130 Location Copy(*this); 131 Copy.Size = NewSize; 132 return Copy; 133 } 134 135 Location getWithoutTBAATag() const { 136 Location Copy(*this); 137 Copy.TBAATag = 0; 138 return Copy; 139 } 140 }; 141 142 /// getLocation - Fill in Loc with information about the memory reference by 143 /// the given instruction. 144 Location getLocation(const LoadInst *LI); 145 Location getLocation(const StoreInst *SI); 146 Location getLocation(const VAArgInst *VI); 147 Location getLocation(const AtomicCmpXchgInst *CXI); 148 Location getLocation(const AtomicRMWInst *RMWI); 149 static Location getLocationForSource(const MemTransferInst *MTI); 150 static Location getLocationForDest(const MemIntrinsic *MI); 151 152 /// Alias analysis result - Either we know for sure that it does not alias, we 153 /// know for sure it must alias, or we don't know anything: The two pointers 154 /// _might_ alias. This enum is designed so you can do things like: 155 /// if (AA.alias(P1, P2)) { ... } 156 /// to check to see if two pointers might alias. 157 /// 158 /// See docs/AliasAnalysis.html for more information on the specific meanings 159 /// of these values. 160 /// 161 enum AliasResult { 162 NoAlias = 0, ///< No dependencies. 163 MayAlias, ///< Anything goes. 164 PartialAlias, ///< Pointers differ, but pointees overlap. 165 MustAlias ///< Pointers are equal. 166 }; 167 168 /// alias - The main low level interface to the alias analysis implementation. 169 /// Returns an AliasResult indicating whether the two pointers are aliased to 170 /// each other. This is the interface that must be implemented by specific 171 /// alias analysis implementations. 172 virtual AliasResult alias(const Location &LocA, const Location &LocB); 173 174 /// alias - A convenience wrapper. 175 AliasResult alias(const Value *V1, uint64_t V1Size, 176 const Value *V2, uint64_t V2Size) { 177 return alias(Location(V1, V1Size), Location(V2, V2Size)); 178 } 179 180 /// alias - A convenience wrapper. 181 AliasResult alias(const Value *V1, const Value *V2) { 182 return alias(V1, UnknownSize, V2, UnknownSize); 183 } 184 185 /// isNoAlias - A trivial helper function to check to see if the specified 186 /// pointers are no-alias. 187 bool isNoAlias(const Location &LocA, const Location &LocB) { 188 return alias(LocA, LocB) == NoAlias; 189 } 190 191 /// isNoAlias - A convenience wrapper. 192 bool isNoAlias(const Value *V1, uint64_t V1Size, 193 const Value *V2, uint64_t V2Size) { 194 return isNoAlias(Location(V1, V1Size), Location(V2, V2Size)); 195 } 196 197 /// isMustAlias - A convenience wrapper. 198 bool isMustAlias(const Location &LocA, const Location &LocB) { 199 return alias(LocA, LocB) == MustAlias; 200 } 201 202 /// isMustAlias - A convenience wrapper. 203 bool isMustAlias(const Value *V1, const Value *V2) { 204 return alias(V1, 1, V2, 1) == MustAlias; 205 } 206 207 /// pointsToConstantMemory - If the specified memory location is 208 /// known to be constant, return true. If OrLocal is true and the 209 /// specified memory location is known to be "local" (derived from 210 /// an alloca), return true. Otherwise return false. 211 virtual bool pointsToConstantMemory(const Location &Loc, 212 bool OrLocal = false); 213 214 /// pointsToConstantMemory - A convenient wrapper. 215 bool pointsToConstantMemory(const Value *P, bool OrLocal = false) { 216 return pointsToConstantMemory(Location(P), OrLocal); 217 } 218 219 //===--------------------------------------------------------------------===// 220 /// Simple mod/ref information... 221 /// 222 223 /// ModRefResult - Represent the result of a mod/ref query. Mod and Ref are 224 /// bits which may be or'd together. 225 /// 226 enum ModRefResult { NoModRef = 0, Ref = 1, Mod = 2, ModRef = 3 }; 227 228 /// These values define additional bits used to define the 229 /// ModRefBehavior values. 230 enum { Nowhere = 0, ArgumentPointees = 4, Anywhere = 8 | ArgumentPointees }; 231 232 /// ModRefBehavior - Summary of how a function affects memory in the program. 233 /// Loads from constant globals are not considered memory accesses for this 234 /// interface. Also, functions may freely modify stack space local to their 235 /// invocation without having to report it through these interfaces. 236 enum ModRefBehavior { 237 /// DoesNotAccessMemory - This function does not perform any non-local loads 238 /// or stores to memory. 239 /// 240 /// This property corresponds to the GCC 'const' attribute. 241 /// This property corresponds to the LLVM IR 'readnone' attribute. 242 /// This property corresponds to the IntrNoMem LLVM intrinsic flag. 243 DoesNotAccessMemory = Nowhere | NoModRef, 244 245 /// OnlyReadsArgumentPointees - The only memory references in this function 246 /// (if it has any) are non-volatile loads from objects pointed to by its 247 /// pointer-typed arguments, with arbitrary offsets. 248 /// 249 /// This property corresponds to the IntrReadArgMem LLVM intrinsic flag. 250 OnlyReadsArgumentPointees = ArgumentPointees | Ref, 251 252 /// OnlyAccessesArgumentPointees - The only memory references in this 253 /// function (if it has any) are non-volatile loads and stores from objects 254 /// pointed to by its pointer-typed arguments, with arbitrary offsets. 255 /// 256 /// This property corresponds to the IntrReadWriteArgMem LLVM intrinsic flag. 257 OnlyAccessesArgumentPointees = ArgumentPointees | ModRef, 258 259 /// OnlyReadsMemory - This function does not perform any non-local stores or 260 /// volatile loads, but may read from any memory location. 261 /// 262 /// This property corresponds to the GCC 'pure' attribute. 263 /// This property corresponds to the LLVM IR 'readonly' attribute. 264 /// This property corresponds to the IntrReadMem LLVM intrinsic flag. 265 OnlyReadsMemory = Anywhere | Ref, 266 267 /// UnknownModRefBehavior - This indicates that the function could not be 268 /// classified into one of the behaviors above. 269 UnknownModRefBehavior = Anywhere | ModRef 270 }; 271 272 /// getModRefBehavior - Return the behavior when calling the given call site. 273 virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS); 274 275 /// getModRefBehavior - Return the behavior when calling the given function. 276 /// For use when the call site is not known. 277 virtual ModRefBehavior getModRefBehavior(const Function *F); 278 279 /// doesNotAccessMemory - If the specified call is known to never read or 280 /// write memory, return true. If the call only reads from known-constant 281 /// memory, it is also legal to return true. Calls that unwind the stack 282 /// are legal for this predicate. 283 /// 284 /// Many optimizations (such as CSE and LICM) can be performed on such calls 285 /// without worrying about aliasing properties, and many calls have this 286 /// property (e.g. calls to 'sin' and 'cos'). 287 /// 288 /// This property corresponds to the GCC 'const' attribute. 289 /// 290 bool doesNotAccessMemory(ImmutableCallSite CS) { 291 return getModRefBehavior(CS) == DoesNotAccessMemory; 292 } 293 294 /// doesNotAccessMemory - If the specified function is known to never read or 295 /// write memory, return true. For use when the call site is not known. 296 /// 297 bool doesNotAccessMemory(const Function *F) { 298 return getModRefBehavior(F) == DoesNotAccessMemory; 299 } 300 301 /// onlyReadsMemory - If the specified call is known to only read from 302 /// non-volatile memory (or not access memory at all), return true. Calls 303 /// that unwind the stack are legal for this predicate. 304 /// 305 /// This property allows many common optimizations to be performed in the 306 /// absence of interfering store instructions, such as CSE of strlen calls. 307 /// 308 /// This property corresponds to the GCC 'pure' attribute. 309 /// 310 bool onlyReadsMemory(ImmutableCallSite CS) { 311 return onlyReadsMemory(getModRefBehavior(CS)); 312 } 313 314 /// onlyReadsMemory - If the specified function is known to only read from 315 /// non-volatile memory (or not access memory at all), return true. For use 316 /// when the call site is not known. 317 /// 318 bool onlyReadsMemory(const Function *F) { 319 return onlyReadsMemory(getModRefBehavior(F)); 320 } 321 322 /// onlyReadsMemory - Return true if functions with the specified behavior are 323 /// known to only read from non-volatile memory (or not access memory at all). 324 /// 325 static bool onlyReadsMemory(ModRefBehavior MRB) { 326 return !(MRB & Mod); 327 } 328 329 /// onlyAccessesArgPointees - Return true if functions with the specified 330 /// behavior are known to read and write at most from objects pointed to by 331 /// their pointer-typed arguments (with arbitrary offsets). 332 /// 333 static bool onlyAccessesArgPointees(ModRefBehavior MRB) { 334 return !(MRB & Anywhere & ~ArgumentPointees); 335 } 336 337 /// doesAccessArgPointees - Return true if functions with the specified 338 /// behavior are known to potentially read or write from objects pointed 339 /// to be their pointer-typed arguments (with arbitrary offsets). 340 /// 341 static bool doesAccessArgPointees(ModRefBehavior MRB) { 342 return (MRB & ModRef) && (MRB & ArgumentPointees); 343 } 344 345 /// getModRefInfo - Return information about whether or not an instruction may 346 /// read or write the specified memory location. An instruction 347 /// that doesn't read or write memory may be trivially LICM'd for example. 348 ModRefResult getModRefInfo(const Instruction *I, 349 const Location &Loc) { 350 switch (I->getOpcode()) { 351 case Instruction::VAArg: return getModRefInfo((const VAArgInst*)I, Loc); 352 case Instruction::Load: return getModRefInfo((const LoadInst*)I, Loc); 353 case Instruction::Store: return getModRefInfo((const StoreInst*)I, Loc); 354 case Instruction::Fence: return getModRefInfo((const FenceInst*)I, Loc); 355 case Instruction::AtomicCmpXchg: 356 return getModRefInfo((const AtomicCmpXchgInst*)I, Loc); 357 case Instruction::AtomicRMW: 358 return getModRefInfo((const AtomicRMWInst*)I, Loc); 359 case Instruction::Call: return getModRefInfo((const CallInst*)I, Loc); 360 case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc); 361 default: return NoModRef; 362 } 363 } 364 365 /// getModRefInfo - A convenience wrapper. 366 ModRefResult getModRefInfo(const Instruction *I, 367 const Value *P, uint64_t Size) { 368 return getModRefInfo(I, Location(P, Size)); 369 } 370 371 /// getModRefInfo (for call sites) - Return whether information about whether 372 /// a particular call site modifies or reads the specified memory location. 373 virtual ModRefResult getModRefInfo(ImmutableCallSite CS, 374 const Location &Loc); 375 376 /// getModRefInfo (for call sites) - A convenience wrapper. 377 ModRefResult getModRefInfo(ImmutableCallSite CS, 378 const Value *P, uint64_t Size) { 379 return getModRefInfo(CS, Location(P, Size)); 380 } 381 382 /// getModRefInfo (for calls) - Return whether information about whether 383 /// a particular call modifies or reads the specified memory location. 384 ModRefResult getModRefInfo(const CallInst *C, const Location &Loc) { 385 return getModRefInfo(ImmutableCallSite(C), Loc); 386 } 387 388 /// getModRefInfo (for calls) - A convenience wrapper. 389 ModRefResult getModRefInfo(const CallInst *C, const Value *P, uint64_t Size) { 390 return getModRefInfo(C, Location(P, Size)); 391 } 392 393 /// getModRefInfo (for invokes) - Return whether information about whether 394 /// a particular invoke modifies or reads the specified memory location. 395 ModRefResult getModRefInfo(const InvokeInst *I, 396 const Location &Loc) { 397 return getModRefInfo(ImmutableCallSite(I), Loc); 398 } 399 400 /// getModRefInfo (for invokes) - A convenience wrapper. 401 ModRefResult getModRefInfo(const InvokeInst *I, 402 const Value *P, uint64_t Size) { 403 return getModRefInfo(I, Location(P, Size)); 404 } 405 406 /// getModRefInfo (for loads) - Return whether information about whether 407 /// a particular load modifies or reads the specified memory location. 408 ModRefResult getModRefInfo(const LoadInst *L, const Location &Loc); 409 410 /// getModRefInfo (for loads) - A convenience wrapper. 411 ModRefResult getModRefInfo(const LoadInst *L, const Value *P, uint64_t Size) { 412 return getModRefInfo(L, Location(P, Size)); 413 } 414 415 /// getModRefInfo (for stores) - Return whether information about whether 416 /// a particular store modifies or reads the specified memory location. 417 ModRefResult getModRefInfo(const StoreInst *S, const Location &Loc); 418 419 /// getModRefInfo (for stores) - A convenience wrapper. 420 ModRefResult getModRefInfo(const StoreInst *S, const Value *P, uint64_t Size){ 421 return getModRefInfo(S, Location(P, Size)); 422 } 423 424 /// getModRefInfo (for fences) - Return whether information about whether 425 /// a particular store modifies or reads the specified memory location. 426 ModRefResult getModRefInfo(const FenceInst *S, const Location &Loc) { 427 // Conservatively correct. (We could possibly be a bit smarter if 428 // Loc is a alloca that doesn't escape.) 429 return ModRef; 430 } 431 432 /// getModRefInfo (for fences) - A convenience wrapper. 433 ModRefResult getModRefInfo(const FenceInst *S, const Value *P, uint64_t Size){ 434 return getModRefInfo(S, Location(P, Size)); 435 } 436 437 /// getModRefInfo (for cmpxchges) - Return whether information about whether 438 /// a particular cmpxchg modifies or reads the specified memory location. 439 ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc); 440 441 /// getModRefInfo (for cmpxchges) - A convenience wrapper. 442 ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX, 443 const Value *P, unsigned Size) { 444 return getModRefInfo(CX, Location(P, Size)); 445 } 446 447 /// getModRefInfo (for atomicrmws) - Return whether information about whether 448 /// a particular atomicrmw modifies or reads the specified memory location. 449 ModRefResult getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc); 450 451 /// getModRefInfo (for atomicrmws) - A convenience wrapper. 452 ModRefResult getModRefInfo(const AtomicRMWInst *RMW, 453 const Value *P, unsigned Size) { 454 return getModRefInfo(RMW, Location(P, Size)); 455 } 456 457 /// getModRefInfo (for va_args) - Return whether information about whether 458 /// a particular va_arg modifies or reads the specified memory location. 459 ModRefResult getModRefInfo(const VAArgInst* I, const Location &Loc); 460 461 /// getModRefInfo (for va_args) - A convenience wrapper. 462 ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, uint64_t Size){ 463 return getModRefInfo(I, Location(P, Size)); 464 } 465 466 /// getModRefInfo - Return information about whether two call sites may refer 467 /// to the same set of memory locations. See 468 /// http://llvm.org/docs/AliasAnalysis.html#ModRefInfo 469 /// for details. 470 virtual ModRefResult getModRefInfo(ImmutableCallSite CS1, 471 ImmutableCallSite CS2); 472 473 /// callCapturesBefore - Return information about whether a particular call 474 /// site modifies or reads the specified memory location. 475 ModRefResult callCapturesBefore(const Instruction *I, 476 const AliasAnalysis::Location &MemLoc, 477 DominatorTree *DT); 478 479 /// callCapturesBefore - A convenience wrapper. 480 ModRefResult callCapturesBefore(const Instruction *I, const Value *P, 481 uint64_t Size, DominatorTree *DT) { 482 return callCapturesBefore(I, Location(P, Size), DT); 483 } 484 485 //===--------------------------------------------------------------------===// 486 /// Higher level methods for querying mod/ref information. 487 /// 488 489 /// canBasicBlockModify - Return true if it is possible for execution of the 490 /// specified basic block to modify the value pointed to by Ptr. 491 bool canBasicBlockModify(const BasicBlock &BB, const Location &Loc); 492 493 /// canBasicBlockModify - A convenience wrapper. 494 bool canBasicBlockModify(const BasicBlock &BB, const Value *P, uint64_t Size){ 495 return canBasicBlockModify(BB, Location(P, Size)); 496 } 497 498 /// canInstructionRangeModify - Return true if it is possible for the 499 /// execution of the specified instructions to modify the value pointed to by 500 /// Ptr. The instructions to consider are all of the instructions in the 501 /// range of [I1,I2] INCLUSIVE. I1 and I2 must be in the same basic block. 502 bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2, 503 const Location &Loc); 504 505 /// canInstructionRangeModify - A convenience wrapper. 506 bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2, 507 const Value *Ptr, uint64_t Size) { 508 return canInstructionRangeModify(I1, I2, Location(Ptr, Size)); 509 } 510 511 //===--------------------------------------------------------------------===// 512 /// Methods that clients should call when they transform the program to allow 513 /// alias analyses to update their internal data structures. Note that these 514 /// methods may be called on any instruction, regardless of whether or not 515 /// they have pointer-analysis implications. 516 /// 517 518 /// deleteValue - This method should be called whenever an LLVM Value is 519 /// deleted from the program, for example when an instruction is found to be 520 /// redundant and is eliminated. 521 /// 522 virtual void deleteValue(Value *V); 523 524 /// copyValue - This method should be used whenever a preexisting value in the 525 /// program is copied or cloned, introducing a new value. Note that analysis 526 /// implementations should tolerate clients that use this method to introduce 527 /// the same value multiple times: if the analysis already knows about a 528 /// value, it should ignore the request. 529 /// 530 virtual void copyValue(Value *From, Value *To); 531 532 /// addEscapingUse - This method should be used whenever an escaping use is 533 /// added to a pointer value. Analysis implementations may either return 534 /// conservative responses for that value in the future, or may recompute 535 /// some or all internal state to continue providing precise responses. 536 /// 537 /// Escaping uses are considered by anything _except_ the following: 538 /// - GEPs or bitcasts of the pointer 539 /// - Loads through the pointer 540 /// - Stores through (but not of) the pointer 541 virtual void addEscapingUse(Use &U); 542 543 /// replaceWithNewValue - This method is the obvious combination of the two 544 /// above, and it provided as a helper to simplify client code. 545 /// 546 void replaceWithNewValue(Value *Old, Value *New) { 547 copyValue(Old, New); 548 deleteValue(Old); 549 } 550}; 551 552// Specialize DenseMapInfo for Location. 553template<> 554struct DenseMapInfo<AliasAnalysis::Location> { 555 static inline AliasAnalysis::Location getEmptyKey() { 556 return 557 AliasAnalysis::Location(DenseMapInfo<const Value *>::getEmptyKey(), 558 0, 0); 559 } 560 static inline AliasAnalysis::Location getTombstoneKey() { 561 return 562 AliasAnalysis::Location(DenseMapInfo<const Value *>::getTombstoneKey(), 563 0, 0); 564 } 565 static unsigned getHashValue(const AliasAnalysis::Location &Val) { 566 return DenseMapInfo<const Value *>::getHashValue(Val.Ptr) ^ 567 DenseMapInfo<uint64_t>::getHashValue(Val.Size) ^ 568 DenseMapInfo<const MDNode *>::getHashValue(Val.TBAATag); 569 } 570 static bool isEqual(const AliasAnalysis::Location &LHS, 571 const AliasAnalysis::Location &RHS) { 572 return LHS.Ptr == RHS.Ptr && 573 LHS.Size == RHS.Size && 574 LHS.TBAATag == RHS.TBAATag; 575 } 576}; 577 578/// isNoAliasCall - Return true if this pointer is returned by a noalias 579/// function. 580bool isNoAliasCall(const Value *V); 581 582/// isIdentifiedObject - Return true if this pointer refers to a distinct and 583/// identifiable object. This returns true for: 584/// Global Variables and Functions (but not Global Aliases) 585/// Allocas and Mallocs 586/// ByVal and NoAlias Arguments 587/// NoAlias returns 588/// 589bool isIdentifiedObject(const Value *V); 590 591/// isKnownNonNull - Return true if this pointer couldn't possibly be null by 592/// its definition. This returns true for allocas, non-extern-weak globals and 593/// byval arguments. 594bool isKnownNonNull(const Value *V); 595 596} // End llvm namespace 597 598#endif 599