1193323Sed//===- llvm/Analysis/AliasAnalysis.h - Alias Analysis Interface -*- C++ -*-===//
2193323Sed//
3193323Sed//                     The LLVM Compiler Infrastructure
4193323Sed//
5193323Sed// This file is distributed under the University of Illinois Open Source
6193323Sed// License. See LICENSE.TXT for details.
7193323Sed//
8193323Sed//===----------------------------------------------------------------------===//
9193323Sed//
10193323Sed// This file defines the generic AliasAnalysis interface, which is used as the
11193323Sed// common interface used by all clients of alias analysis information, and
12193323Sed// implemented by all alias analysis implementations.  Mod/Ref information is
13193323Sed// also captured by this interface.
14193323Sed//
15193323Sed// Implementations of this interface must implement the various virtual methods,
16193323Sed// which automatically provides functionality for the entire suite of client
17193323Sed// APIs.
18193323Sed//
19218893Sdim// This API identifies memory regions with the Location class. The pointer
20218893Sdim// component specifies the base memory address of the region. The Size specifies
21218893Sdim// the maximum size (in address units) of the memory region, or UnknownSize if
22218893Sdim// the size is not known. The TBAA tag identifies the "type" of the memory
23218893Sdim// reference; see the TypeBasedAliasAnalysis class for details.
24193323Sed//
25218893Sdim// Some non-obvious details include:
26218893Sdim//  - Pointers that point to two completely different objects in memory never
27218893Sdim//    alias, regardless of the value of the Size component.
28218893Sdim//  - NoAlias doesn't imply inequal pointers. The most obvious example of this
29218893Sdim//    is two pointers to constant memory. Even if they are equal, constant
30218893Sdim//    memory is never stored to, so there will never be any dependencies.
31218893Sdim//    In this and other situations, the pointers may be both NoAlias and
32218893Sdim//    MustAlias at the same time. The current API can only return one result,
33218893Sdim//    though this is rarely a problem in practice.
34218893Sdim//
35193323Sed//===----------------------------------------------------------------------===//
36193323Sed
37252723Sdim#ifndef LLVM_ANALYSIS_ALIASANALYSIS_H
38252723Sdim#define LLVM_ANALYSIS_ALIASANALYSIS_H
39193323Sed
40252723Sdim#include "llvm/ADT/DenseMap.h"
41193323Sed#include "llvm/Support/CallSite.h"
42193323Sed
43193323Sednamespace llvm {
44193323Sed
45193323Sedclass LoadInst;
46193323Sedclass StoreInst;
47193323Sedclass VAArgInst;
48245431Sdimclass DataLayout;
49245431Sdimclass TargetLibraryInfo;
50193323Sedclass Pass;
51193323Sedclass AnalysisUsage;
52218893Sdimclass MemTransferInst;
53218893Sdimclass MemIntrinsic;
54245431Sdimclass DominatorTree;
55193323Sed
56193323Sedclass AliasAnalysis {
57193323Sedprotected:
58245431Sdim  const DataLayout *TD;
59245431Sdim  const TargetLibraryInfo *TLI;
60212904Sdim
61212904Sdimprivate:
62193323Sed  AliasAnalysis *AA;       // Previous Alias Analysis to chain to.
63193323Sed
64212904Sdimprotected:
65193323Sed  /// InitializeAliasAnalysis - Subclasses must call this method to initialize
66193323Sed  /// the AliasAnalysis interface before any other methods are called.  This is
67193323Sed  /// typically called by the run* methods of these subclasses.  This may be
68193323Sed  /// called multiple times.
69193323Sed  ///
70193323Sed  void InitializeAliasAnalysis(Pass *P);
71193323Sed
72193323Sed  /// getAnalysisUsage - All alias analysis implementations should invoke this
73198090Srdivacky  /// directly (using AliasAnalysis::getAnalysisUsage(AU)).
74193323Sed  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
75193323Sed
76193323Sedpublic:
77193323Sed  static char ID; // Class identification, replacement for typeinfo
78245431Sdim  AliasAnalysis() : TD(0), TLI(0), AA(0) {}
79193323Sed  virtual ~AliasAnalysis();  // We want to be subclassed
80193323Sed
81212904Sdim  /// UnknownSize - This is a special value which can be used with the
82212904Sdim  /// size arguments in alias queries to indicate that the caller does not
83212904Sdim  /// know the sizes of the potential memory references.
84218893Sdim  static uint64_t const UnknownSize = ~UINT64_C(0);
85212904Sdim
86245431Sdim  /// getDataLayout - Return a pointer to the current DataLayout object, or
87245431Sdim  /// null if no DataLayout object is available.
88193323Sed  ///
89245431Sdim  const DataLayout *getDataLayout() const { return TD; }
90193323Sed
91245431Sdim  /// getTargetLibraryInfo - Return a pointer to the current TargetLibraryInfo
92245431Sdim  /// object, or null if no TargetLibraryInfo object is available.
93245431Sdim  ///
94245431Sdim  const TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
95245431Sdim
96245431Sdim  /// getTypeStoreSize - Return the DataLayout store size for the given type,
97198090Srdivacky  /// if known, or a conservative value otherwise.
98198090Srdivacky  ///
99226890Sdim  uint64_t getTypeStoreSize(Type *Ty);
100198090Srdivacky
101193323Sed  //===--------------------------------------------------------------------===//
102193323Sed  /// Alias Queries...
103193323Sed  ///
104193323Sed
105218893Sdim  /// Location - A description of a memory location.
106218893Sdim  struct Location {
107218893Sdim    /// Ptr - The address of the start of the location.
108218893Sdim    const Value *Ptr;
109218893Sdim    /// Size - The maximum size of the location, in address-units, or
110218893Sdim    /// UnknownSize if the size is not known.  Note that an unknown size does
111218893Sdim    /// not mean the pointer aliases the entire virtual address space, because
112218893Sdim    /// there are restrictions on stepping out of one object and into another.
113218893Sdim    /// See http://llvm.org/docs/LangRef.html#pointeraliasing
114218893Sdim    uint64_t Size;
115218893Sdim    /// TBAATag - The metadata node which describes the TBAA type of
116218893Sdim    /// the location, or null if there is no known unique tag.
117218893Sdim    const MDNode *TBAATag;
118218893Sdim
119218893Sdim    explicit Location(const Value *P = 0, uint64_t S = UnknownSize,
120218893Sdim                      const MDNode *N = 0)
121218893Sdim      : Ptr(P), Size(S), TBAATag(N) {}
122218893Sdim
123218893Sdim    Location getWithNewPtr(const Value *NewPtr) const {
124218893Sdim      Location Copy(*this);
125218893Sdim      Copy.Ptr = NewPtr;
126218893Sdim      return Copy;
127218893Sdim    }
128218893Sdim
129218893Sdim    Location getWithNewSize(uint64_t NewSize) const {
130218893Sdim      Location Copy(*this);
131218893Sdim      Copy.Size = NewSize;
132218893Sdim      return Copy;
133218893Sdim    }
134218893Sdim
135218893Sdim    Location getWithoutTBAATag() const {
136218893Sdim      Location Copy(*this);
137218893Sdim      Copy.TBAATag = 0;
138218893Sdim      return Copy;
139218893Sdim    }
140218893Sdim  };
141218893Sdim
142218893Sdim  /// getLocation - Fill in Loc with information about the memory reference by
143218893Sdim  /// the given instruction.
144218893Sdim  Location getLocation(const LoadInst *LI);
145218893Sdim  Location getLocation(const StoreInst *SI);
146218893Sdim  Location getLocation(const VAArgInst *VI);
147226890Sdim  Location getLocation(const AtomicCmpXchgInst *CXI);
148226890Sdim  Location getLocation(const AtomicRMWInst *RMWI);
149218893Sdim  static Location getLocationForSource(const MemTransferInst *MTI);
150218893Sdim  static Location getLocationForDest(const MemIntrinsic *MI);
151218893Sdim
152193323Sed  /// Alias analysis result - Either we know for sure that it does not alias, we
153193323Sed  /// know for sure it must alias, or we don't know anything: The two pointers
154193323Sed  /// _might_ alias.  This enum is designed so you can do things like:
155193323Sed  ///     if (AA.alias(P1, P2)) { ... }
156193323Sed  /// to check to see if two pointers might alias.
157193323Sed  ///
158212904Sdim  /// See docs/AliasAnalysis.html for more information on the specific meanings
159212904Sdim  /// of these values.
160212904Sdim  ///
161218893Sdim  enum AliasResult {
162218893Sdim    NoAlias = 0,        ///< No dependencies.
163218893Sdim    MayAlias,           ///< Anything goes.
164218893Sdim    PartialAlias,       ///< Pointers differ, but pointees overlap.
165218893Sdim    MustAlias           ///< Pointers are equal.
166218893Sdim  };
167193323Sed
168193323Sed  /// alias - The main low level interface to the alias analysis implementation.
169218893Sdim  /// Returns an AliasResult indicating whether the two pointers are aliased to
170218893Sdim  /// each other.  This is the interface that must be implemented by specific
171218893Sdim  /// alias analysis implementations.
172218893Sdim  virtual AliasResult alias(const Location &LocA, const Location &LocB);
173193323Sed
174218893Sdim  /// alias - A convenience wrapper.
175218893Sdim  AliasResult alias(const Value *V1, uint64_t V1Size,
176218893Sdim                    const Value *V2, uint64_t V2Size) {
177218893Sdim    return alias(Location(V1, V1Size), Location(V2, V2Size));
178218893Sdim  }
179218893Sdim
180218893Sdim  /// alias - A convenience wrapper.
181212904Sdim  AliasResult alias(const Value *V1, const Value *V2) {
182212904Sdim    return alias(V1, UnknownSize, V2, UnknownSize);
183212904Sdim  }
184212904Sdim
185199989Srdivacky  /// isNoAlias - A trivial helper function to check to see if the specified
186199989Srdivacky  /// pointers are no-alias.
187218893Sdim  bool isNoAlias(const Location &LocA, const Location &LocB) {
188218893Sdim    return alias(LocA, LocB) == NoAlias;
189199989Srdivacky  }
190193323Sed
191218893Sdim  /// isNoAlias - A convenience wrapper.
192218893Sdim  bool isNoAlias(const Value *V1, uint64_t V1Size,
193218893Sdim                 const Value *V2, uint64_t V2Size) {
194218893Sdim    return isNoAlias(Location(V1, V1Size), Location(V2, V2Size));
195218893Sdim  }
196218893Sdim
197245431Sdim  /// isNoAlias - A convenience wrapper.
198245431Sdim  bool isNoAlias(const Value *V1, const Value *V2) {
199245431Sdim    return isNoAlias(Location(V1), Location(V2));
200245431Sdim  }
201245431Sdim
202218893Sdim  /// isMustAlias - A convenience wrapper.
203218893Sdim  bool isMustAlias(const Location &LocA, const Location &LocB) {
204218893Sdim    return alias(LocA, LocB) == MustAlias;
205218893Sdim  }
206193323Sed
207218893Sdim  /// isMustAlias - A convenience wrapper.
208218893Sdim  bool isMustAlias(const Value *V1, const Value *V2) {
209218893Sdim    return alias(V1, 1, V2, 1) == MustAlias;
210218893Sdim  }
211218893Sdim
212218893Sdim  /// pointsToConstantMemory - If the specified memory location is
213218893Sdim  /// known to be constant, return true. If OrLocal is true and the
214218893Sdim  /// specified memory location is known to be "local" (derived from
215218893Sdim  /// an alloca), return true. Otherwise return false.
216218893Sdim  virtual bool pointsToConstantMemory(const Location &Loc,
217218893Sdim                                      bool OrLocal = false);
218218893Sdim
219218893Sdim  /// pointsToConstantMemory - A convenient wrapper.
220218893Sdim  bool pointsToConstantMemory(const Value *P, bool OrLocal = false) {
221218893Sdim    return pointsToConstantMemory(Location(P), OrLocal);
222218893Sdim  }
223218893Sdim
224193323Sed  //===--------------------------------------------------------------------===//
225193323Sed  /// Simple mod/ref information...
226193323Sed  ///
227193323Sed
228193323Sed  /// ModRefResult - Represent the result of a mod/ref query.  Mod and Ref are
229193323Sed  /// bits which may be or'd together.
230193323Sed  ///
231193323Sed  enum ModRefResult { NoModRef = 0, Ref = 1, Mod = 2, ModRef = 3 };
232193323Sed
233218893Sdim  /// These values define additional bits used to define the
234218893Sdim  /// ModRefBehavior values.
235218893Sdim  enum { Nowhere = 0, ArgumentPointees = 4, Anywhere = 8 | ArgumentPointees };
236193323Sed
237193323Sed  /// ModRefBehavior - Summary of how a function affects memory in the program.
238193323Sed  /// Loads from constant globals are not considered memory accesses for this
239193323Sed  /// interface.  Also, functions may freely modify stack space local to their
240193323Sed  /// invocation without having to report it through these interfaces.
241193323Sed  enum ModRefBehavior {
242218893Sdim    /// DoesNotAccessMemory - This function does not perform any non-local loads
243218893Sdim    /// or stores to memory.
244218893Sdim    ///
245218893Sdim    /// This property corresponds to the GCC 'const' attribute.
246218893Sdim    /// This property corresponds to the LLVM IR 'readnone' attribute.
247218893Sdim    /// This property corresponds to the IntrNoMem LLVM intrinsic flag.
248218893Sdim    DoesNotAccessMemory = Nowhere | NoModRef,
249193323Sed
250218893Sdim    /// OnlyReadsArgumentPointees - The only memory references in this function
251218893Sdim    /// (if it has any) are non-volatile loads from objects pointed to by its
252218893Sdim    /// pointer-typed arguments, with arbitrary offsets.
253218893Sdim    ///
254218893Sdim    /// This property corresponds to the IntrReadArgMem LLVM intrinsic flag.
255218893Sdim    OnlyReadsArgumentPointees = ArgumentPointees | Ref,
256193323Sed
257218893Sdim    /// OnlyAccessesArgumentPointees - The only memory references in this
258218893Sdim    /// function (if it has any) are non-volatile loads and stores from objects
259218893Sdim    /// pointed to by its pointer-typed arguments, with arbitrary offsets.
260218893Sdim    ///
261218893Sdim    /// This property corresponds to the IntrReadWriteArgMem LLVM intrinsic flag.
262218893Sdim    OnlyAccessesArgumentPointees = ArgumentPointees | ModRef,
263193323Sed
264218893Sdim    /// OnlyReadsMemory - This function does not perform any non-local stores or
265218893Sdim    /// volatile loads, but may read from any memory location.
266218893Sdim    ///
267218893Sdim    /// This property corresponds to the GCC 'pure' attribute.
268218893Sdim    /// This property corresponds to the LLVM IR 'readonly' attribute.
269218893Sdim    /// This property corresponds to the IntrReadMem LLVM intrinsic flag.
270218893Sdim    OnlyReadsMemory = Anywhere | Ref,
271193323Sed
272218893Sdim    /// UnknownModRefBehavior - This indicates that the function could not be
273218893Sdim    /// classified into one of the behaviors above.
274218893Sdim    UnknownModRefBehavior = Anywhere | ModRef
275193323Sed  };
276193323Sed
277193323Sed  /// getModRefBehavior - Return the behavior when calling the given call site.
278212904Sdim  virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
279193323Sed
280193323Sed  /// getModRefBehavior - Return the behavior when calling the given function.
281193323Sed  /// For use when the call site is not known.
282212904Sdim  virtual ModRefBehavior getModRefBehavior(const Function *F);
283193323Sed
284193323Sed  /// doesNotAccessMemory - If the specified call is known to never read or
285193323Sed  /// write memory, return true.  If the call only reads from known-constant
286193323Sed  /// memory, it is also legal to return true.  Calls that unwind the stack
287193323Sed  /// are legal for this predicate.
288193323Sed  ///
289193323Sed  /// Many optimizations (such as CSE and LICM) can be performed on such calls
290193323Sed  /// without worrying about aliasing properties, and many calls have this
291193323Sed  /// property (e.g. calls to 'sin' and 'cos').
292193323Sed  ///
293193323Sed  /// This property corresponds to the GCC 'const' attribute.
294193323Sed  ///
295212904Sdim  bool doesNotAccessMemory(ImmutableCallSite CS) {
296193323Sed    return getModRefBehavior(CS) == DoesNotAccessMemory;
297193323Sed  }
298193323Sed
299193323Sed  /// doesNotAccessMemory - If the specified function is known to never read or
300193323Sed  /// write memory, return true.  For use when the call site is not known.
301193323Sed  ///
302212904Sdim  bool doesNotAccessMemory(const Function *F) {
303193323Sed    return getModRefBehavior(F) == DoesNotAccessMemory;
304193323Sed  }
305193323Sed
306193323Sed  /// onlyReadsMemory - If the specified call is known to only read from
307193323Sed  /// non-volatile memory (or not access memory at all), return true.  Calls
308193323Sed  /// that unwind the stack are legal for this predicate.
309193323Sed  ///
310193323Sed  /// This property allows many common optimizations to be performed in the
311193323Sed  /// absence of interfering store instructions, such as CSE of strlen calls.
312193323Sed  ///
313193323Sed  /// This property corresponds to the GCC 'pure' attribute.
314193323Sed  ///
315212904Sdim  bool onlyReadsMemory(ImmutableCallSite CS) {
316218893Sdim    return onlyReadsMemory(getModRefBehavior(CS));
317193323Sed  }
318193323Sed
319193323Sed  /// onlyReadsMemory - If the specified function is known to only read from
320193323Sed  /// non-volatile memory (or not access memory at all), return true.  For use
321193323Sed  /// when the call site is not known.
322193323Sed  ///
323212904Sdim  bool onlyReadsMemory(const Function *F) {
324218893Sdim    return onlyReadsMemory(getModRefBehavior(F));
325193323Sed  }
326193323Sed
327218893Sdim  /// onlyReadsMemory - Return true if functions with the specified behavior are
328218893Sdim  /// known to only read from non-volatile memory (or not access memory at all).
329218893Sdim  ///
330218893Sdim  static bool onlyReadsMemory(ModRefBehavior MRB) {
331218893Sdim    return !(MRB & Mod);
332218893Sdim  }
333193323Sed
334218893Sdim  /// onlyAccessesArgPointees - Return true if functions with the specified
335218893Sdim  /// behavior are known to read and write at most from objects pointed to by
336218893Sdim  /// their pointer-typed arguments (with arbitrary offsets).
337218893Sdim  ///
338218893Sdim  static bool onlyAccessesArgPointees(ModRefBehavior MRB) {
339218893Sdim    return !(MRB & Anywhere & ~ArgumentPointees);
340218893Sdim  }
341218893Sdim
342218893Sdim  /// doesAccessArgPointees - Return true if functions with the specified
343235633Sdim  /// behavior are known to potentially read or write from objects pointed
344218893Sdim  /// to be their pointer-typed arguments (with arbitrary offsets).
345218893Sdim  ///
346218893Sdim  static bool doesAccessArgPointees(ModRefBehavior MRB) {
347218893Sdim    return (MRB & ModRef) && (MRB & ArgumentPointees);
348218893Sdim  }
349218893Sdim
350193323Sed  /// getModRefInfo - Return information about whether or not an instruction may
351218893Sdim  /// read or write the specified memory location.  An instruction
352193323Sed  /// that doesn't read or write memory may be trivially LICM'd for example.
353218893Sdim  ModRefResult getModRefInfo(const Instruction *I,
354218893Sdim                             const Location &Loc) {
355218893Sdim    switch (I->getOpcode()) {
356218893Sdim    case Instruction::VAArg:  return getModRefInfo((const VAArgInst*)I, Loc);
357218893Sdim    case Instruction::Load:   return getModRefInfo((const LoadInst*)I,  Loc);
358218893Sdim    case Instruction::Store:  return getModRefInfo((const StoreInst*)I, Loc);
359226890Sdim    case Instruction::Fence:  return getModRefInfo((const FenceInst*)I, Loc);
360226890Sdim    case Instruction::AtomicCmpXchg:
361226890Sdim      return getModRefInfo((const AtomicCmpXchgInst*)I, Loc);
362226890Sdim    case Instruction::AtomicRMW:
363226890Sdim      return getModRefInfo((const AtomicRMWInst*)I, Loc);
364218893Sdim    case Instruction::Call:   return getModRefInfo((const CallInst*)I,  Loc);
365218893Sdim    case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc);
366218893Sdim    default:                  return NoModRef;
367218893Sdim    }
368218893Sdim  }
369193323Sed
370218893Sdim  /// getModRefInfo - A convenience wrapper.
371218893Sdim  ModRefResult getModRefInfo(const Instruction *I,
372218893Sdim                             const Value *P, uint64_t Size) {
373218893Sdim    return getModRefInfo(I, Location(P, Size));
374218893Sdim  }
375218893Sdim
376252723Sdim  /// getModRefInfo (for call sites) - Return information about whether
377218893Sdim  /// a particular call site modifies or reads the specified memory location.
378212904Sdim  virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
379218893Sdim                                     const Location &Loc);
380193323Sed
381218893Sdim  /// getModRefInfo (for call sites) - A convenience wrapper.
382218893Sdim  ModRefResult getModRefInfo(ImmutableCallSite CS,
383218893Sdim                             const Value *P, uint64_t Size) {
384218893Sdim    return getModRefInfo(CS, Location(P, Size));
385218893Sdim  }
386218893Sdim
387252723Sdim  /// getModRefInfo (for calls) - Return information about whether
388218893Sdim  /// a particular call modifies or reads the specified memory location.
389218893Sdim  ModRefResult getModRefInfo(const CallInst *C, const Location &Loc) {
390218893Sdim    return getModRefInfo(ImmutableCallSite(C), Loc);
391218893Sdim  }
392218893Sdim
393218893Sdim  /// getModRefInfo (for calls) - A convenience wrapper.
394218893Sdim  ModRefResult getModRefInfo(const CallInst *C, const Value *P, uint64_t Size) {
395218893Sdim    return getModRefInfo(C, Location(P, Size));
396218893Sdim  }
397218893Sdim
398252723Sdim  /// getModRefInfo (for invokes) - Return information about whether
399218893Sdim  /// a particular invoke modifies or reads the specified memory location.
400218893Sdim  ModRefResult getModRefInfo(const InvokeInst *I,
401218893Sdim                             const Location &Loc) {
402218893Sdim    return getModRefInfo(ImmutableCallSite(I), Loc);
403218893Sdim  }
404218893Sdim
405218893Sdim  /// getModRefInfo (for invokes) - A convenience wrapper.
406218893Sdim  ModRefResult getModRefInfo(const InvokeInst *I,
407218893Sdim                             const Value *P, uint64_t Size) {
408218893Sdim    return getModRefInfo(I, Location(P, Size));
409218893Sdim  }
410218893Sdim
411252723Sdim  /// getModRefInfo (for loads) - Return information about whether
412218893Sdim  /// a particular load modifies or reads the specified memory location.
413218893Sdim  ModRefResult getModRefInfo(const LoadInst *L, const Location &Loc);
414218893Sdim
415218893Sdim  /// getModRefInfo (for loads) - A convenience wrapper.
416218893Sdim  ModRefResult getModRefInfo(const LoadInst *L, const Value *P, uint64_t Size) {
417218893Sdim    return getModRefInfo(L, Location(P, Size));
418218893Sdim  }
419218893Sdim
420252723Sdim  /// getModRefInfo (for stores) - Return information about whether
421218893Sdim  /// a particular store modifies or reads the specified memory location.
422218893Sdim  ModRefResult getModRefInfo(const StoreInst *S, const Location &Loc);
423218893Sdim
424218893Sdim  /// getModRefInfo (for stores) - A convenience wrapper.
425218893Sdim  ModRefResult getModRefInfo(const StoreInst *S, const Value *P, uint64_t Size){
426218893Sdim    return getModRefInfo(S, Location(P, Size));
427218893Sdim  }
428218893Sdim
429252723Sdim  /// getModRefInfo (for fences) - Return information about whether
430226890Sdim  /// a particular store modifies or reads the specified memory location.
431226890Sdim  ModRefResult getModRefInfo(const FenceInst *S, const Location &Loc) {
432226890Sdim    // Conservatively correct.  (We could possibly be a bit smarter if
433226890Sdim    // Loc is a alloca that doesn't escape.)
434226890Sdim    return ModRef;
435226890Sdim  }
436226890Sdim
437226890Sdim  /// getModRefInfo (for fences) - A convenience wrapper.
438226890Sdim  ModRefResult getModRefInfo(const FenceInst *S, const Value *P, uint64_t Size){
439226890Sdim    return getModRefInfo(S, Location(P, Size));
440226890Sdim  }
441226890Sdim
442252723Sdim  /// getModRefInfo (for cmpxchges) - Return information about whether
443226890Sdim  /// a particular cmpxchg modifies or reads the specified memory location.
444226890Sdim  ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc);
445226890Sdim
446226890Sdim  /// getModRefInfo (for cmpxchges) - A convenience wrapper.
447226890Sdim  ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX,
448226890Sdim                             const Value *P, unsigned Size) {
449226890Sdim    return getModRefInfo(CX, Location(P, Size));
450226890Sdim  }
451226890Sdim
452252723Sdim  /// getModRefInfo (for atomicrmws) - Return information about whether
453226890Sdim  /// a particular atomicrmw modifies or reads the specified memory location.
454226890Sdim  ModRefResult getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc);
455226890Sdim
456226890Sdim  /// getModRefInfo (for atomicrmws) - A convenience wrapper.
457226890Sdim  ModRefResult getModRefInfo(const AtomicRMWInst *RMW,
458226890Sdim                             const Value *P, unsigned Size) {
459226890Sdim    return getModRefInfo(RMW, Location(P, Size));
460226890Sdim  }
461226890Sdim
462252723Sdim  /// getModRefInfo (for va_args) - Return information about whether
463218893Sdim  /// a particular va_arg modifies or reads the specified memory location.
464218893Sdim  ModRefResult getModRefInfo(const VAArgInst* I, const Location &Loc);
465218893Sdim
466218893Sdim  /// getModRefInfo (for va_args) - A convenience wrapper.
467218893Sdim  ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, uint64_t Size){
468218893Sdim    return getModRefInfo(I, Location(P, Size));
469218893Sdim  }
470218893Sdim
471193323Sed  /// getModRefInfo - Return information about whether two call sites may refer
472212904Sdim  /// to the same set of memory locations.  See
473212904Sdim  ///   http://llvm.org/docs/AliasAnalysis.html#ModRefInfo
474212904Sdim  /// for details.
475212904Sdim  virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
476212904Sdim                                     ImmutableCallSite CS2);
477193323Sed
478245431Sdim  /// callCapturesBefore - Return information about whether a particular call
479245431Sdim  /// site modifies or reads the specified memory location.
480245431Sdim  ModRefResult callCapturesBefore(const Instruction *I,
481245431Sdim                                  const AliasAnalysis::Location &MemLoc,
482245431Sdim                                  DominatorTree *DT);
483245431Sdim
484245431Sdim  /// callCapturesBefore - A convenience wrapper.
485245431Sdim  ModRefResult callCapturesBefore(const Instruction *I, const Value *P,
486245431Sdim                                  uint64_t Size, DominatorTree *DT) {
487245431Sdim    return callCapturesBefore(I, Location(P, Size), DT);
488245431Sdim  }
489245431Sdim
490193323Sed  //===--------------------------------------------------------------------===//
491193323Sed  /// Higher level methods for querying mod/ref information.
492193323Sed  ///
493193323Sed
494193323Sed  /// canBasicBlockModify - Return true if it is possible for execution of the
495193323Sed  /// specified basic block to modify the value pointed to by Ptr.
496218893Sdim  bool canBasicBlockModify(const BasicBlock &BB, const Location &Loc);
497193323Sed
498218893Sdim  /// canBasicBlockModify - A convenience wrapper.
499218893Sdim  bool canBasicBlockModify(const BasicBlock &BB, const Value *P, uint64_t Size){
500218893Sdim    return canBasicBlockModify(BB, Location(P, Size));
501218893Sdim  }
502218893Sdim
503193323Sed  /// canInstructionRangeModify - Return true if it is possible for the
504193323Sed  /// execution of the specified instructions to modify the value pointed to by
505193323Sed  /// Ptr.  The instructions to consider are all of the instructions in the
506193323Sed  /// range of [I1,I2] INCLUSIVE.  I1 and I2 must be in the same basic block.
507193323Sed  bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
508218893Sdim                                 const Location &Loc);
509193323Sed
510218893Sdim  /// canInstructionRangeModify - A convenience wrapper.
511218893Sdim  bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
512218893Sdim                                 const Value *Ptr, uint64_t Size) {
513218893Sdim    return canInstructionRangeModify(I1, I2, Location(Ptr, Size));
514218893Sdim  }
515218893Sdim
516193323Sed  //===--------------------------------------------------------------------===//
517193323Sed  /// Methods that clients should call when they transform the program to allow
518193323Sed  /// alias analyses to update their internal data structures.  Note that these
519193323Sed  /// methods may be called on any instruction, regardless of whether or not
520193323Sed  /// they have pointer-analysis implications.
521193323Sed  ///
522193323Sed
523193323Sed  /// deleteValue - This method should be called whenever an LLVM Value is
524193323Sed  /// deleted from the program, for example when an instruction is found to be
525193323Sed  /// redundant and is eliminated.
526193323Sed  ///
527193323Sed  virtual void deleteValue(Value *V);
528193323Sed
529193323Sed  /// copyValue - This method should be used whenever a preexisting value in the
530193323Sed  /// program is copied or cloned, introducing a new value.  Note that analysis
531193323Sed  /// implementations should tolerate clients that use this method to introduce
532193323Sed  /// the same value multiple times: if the analysis already knows about a
533193323Sed  /// value, it should ignore the request.
534193323Sed  ///
535193323Sed  virtual void copyValue(Value *From, Value *To);
536193323Sed
537218893Sdim  /// addEscapingUse - This method should be used whenever an escaping use is
538218893Sdim  /// added to a pointer value.  Analysis implementations may either return
539218893Sdim  /// conservative responses for that value in the future, or may recompute
540218893Sdim  /// some or all internal state to continue providing precise responses.
541218893Sdim  ///
542218893Sdim  /// Escaping uses are considered by anything _except_ the following:
543218893Sdim  ///  - GEPs or bitcasts of the pointer
544218893Sdim  ///  - Loads through the pointer
545218893Sdim  ///  - Stores through (but not of) the pointer
546218893Sdim  virtual void addEscapingUse(Use &U);
547218893Sdim
548193323Sed  /// replaceWithNewValue - This method is the obvious combination of the two
549193323Sed  /// above, and it provided as a helper to simplify client code.
550193323Sed  ///
551193323Sed  void replaceWithNewValue(Value *Old, Value *New) {
552193323Sed    copyValue(Old, New);
553193323Sed    deleteValue(Old);
554193323Sed  }
555193323Sed};
556193323Sed
557223017Sdim// Specialize DenseMapInfo for Location.
558223017Sdimtemplate<>
559223017Sdimstruct DenseMapInfo<AliasAnalysis::Location> {
560223017Sdim  static inline AliasAnalysis::Location getEmptyKey() {
561223017Sdim    return
562223017Sdim      AliasAnalysis::Location(DenseMapInfo<const Value *>::getEmptyKey(),
563223017Sdim                              0, 0);
564223017Sdim  }
565223017Sdim  static inline AliasAnalysis::Location getTombstoneKey() {
566223017Sdim    return
567223017Sdim      AliasAnalysis::Location(DenseMapInfo<const Value *>::getTombstoneKey(),
568223017Sdim                              0, 0);
569223017Sdim  }
570223017Sdim  static unsigned getHashValue(const AliasAnalysis::Location &Val) {
571223017Sdim    return DenseMapInfo<const Value *>::getHashValue(Val.Ptr) ^
572223017Sdim           DenseMapInfo<uint64_t>::getHashValue(Val.Size) ^
573223017Sdim           DenseMapInfo<const MDNode *>::getHashValue(Val.TBAATag);
574223017Sdim  }
575223017Sdim  static bool isEqual(const AliasAnalysis::Location &LHS,
576223017Sdim                      const AliasAnalysis::Location &RHS) {
577223017Sdim    return LHS.Ptr == RHS.Ptr &&
578223017Sdim           LHS.Size == RHS.Size &&
579223017Sdim           LHS.TBAATag == RHS.TBAATag;
580223017Sdim  }
581223017Sdim};
582223017Sdim
583193323Sed/// isNoAliasCall - Return true if this pointer is returned by a noalias
584193323Sed/// function.
585193323Sedbool isNoAliasCall(const Value *V);
586193323Sed
587263509Sdim/// isNoAliasArgument - Return true if this is an argument with the noalias
588263509Sdim/// attribute.
589263509Sdimbool isNoAliasArgument(const Value *V);
590263509Sdim
591193323Sed/// isIdentifiedObject - Return true if this pointer refers to a distinct and
592193323Sed/// identifiable object.  This returns true for:
593198090Srdivacky///    Global Variables and Functions (but not Global Aliases)
594252723Sdim///    Allocas
595193323Sed///    ByVal and NoAlias Arguments
596252723Sdim///    NoAlias returns (e.g. calls to malloc)
597193323Sed///
598193323Sedbool isIdentifiedObject(const Value *V);
599193323Sed
600193323Sed} // End llvm namespace
601193323Sed
602193323Sed#endif
603