//===- llvm/Analysis/AliasSetTracker.h - Build Alias Sets -------*- C++ -*-===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file defines two classes: AliasSetTracker and AliasSet. These interface
// are used to classify a collection of pointer references into a maximal number
// of disjoint sets. Each AliasSet object constructed by the AliasSetTracker
// object refers to memory disjoint from the other sets.
-//
+//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_ALIASSETTRACKER_H
#define LLVM_ANALYSIS_ALIASSETTRACKER_H
-#include "llvm/Support/CallSite.h"
-#include "Support/iterator"
-#include "Support/hash_map"
-#include "Support/ilist"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/ADT/ilist_node.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/ValueHandle.h"
+#include <vector>
namespace llvm {
-class AliasAnalysis;
class LoadInst;
class StoreInst;
+class VAArgInst;
class AliasSetTracker;
class AliasSet;
-class AliasSet {
+class AliasSet : public ilist_node<AliasSet> {
friend class AliasSetTracker;
- struct PointerRec;
- typedef std::pair<Value* const, PointerRec> HashNodePair;
-
class PointerRec {
- HashNodePair **PrevInList, *NextInList;
+ Value *Val; // The pointer this record corresponds to.
+ PointerRec **PrevInList, *NextInList;
AliasSet *AS;
- unsigned Size;
+ uint64_t Size;
+ AAMDNodes AAInfo;
public:
- PointerRec() : PrevInList(0), NextInList(0), AS(0), Size(0) {}
+ PointerRec(Value *V)
+ : Val(V), PrevInList(nullptr), NextInList(nullptr), AS(nullptr), Size(0),
+ AAInfo(DenseMapInfo<AAMDNodes>::getEmptyKey()) {}
- HashNodePair *getNext() const { return NextInList; }
- bool hasAliasSet() const { return AS != 0; }
+ Value *getValue() const { return Val; }
+
+ PointerRec *getNext() const { return NextInList; }
+ bool hasAliasSet() const { return AS != nullptr; }
- HashNodePair** setPrevInList(HashNodePair **PIL) {
+ PointerRec** setPrevInList(PointerRec **PIL) {
PrevInList = PIL;
return &NextInList;
}
- void updateSize(unsigned NewSize) {
+ void updateSizeAndAAInfo(uint64_t NewSize, const AAMDNodes &NewAAInfo) {
if (NewSize > Size) Size = NewSize;
+
+ if (AAInfo == DenseMapInfo<AAMDNodes>::getEmptyKey())
+ // We don't have a AAInfo yet. Set it to NewAAInfo.
+ AAInfo = NewAAInfo;
+ else if (AAInfo != NewAAInfo)
+ // NewAAInfo conflicts with AAInfo.
+ AAInfo = DenseMapInfo<AAMDNodes>::getTombstoneKey();
}
- unsigned getSize() const { return Size; }
+ uint64_t getSize() const { return Size; }
+
+ /// getAAInfo - Return the AAInfo, or null if there is no
+ /// information or conflicting information.
+ AAMDNodes getAAInfo() const {
+ // If we have missing or conflicting AAInfo, return null.
+ if (AAInfo == DenseMapInfo<AAMDNodes>::getEmptyKey() ||
+ AAInfo == DenseMapInfo<AAMDNodes>::getTombstoneKey())
+ return AAMDNodes();
+ return AAInfo;
+ }
- AliasSet *getAliasSet(AliasSetTracker &AST) {
+ AliasSet *getAliasSet(AliasSetTracker &AST) {
assert(AS && "No AliasSet yet!");
if (AS->Forward) {
AliasSet *OldAS = AS;
AS = OldAS->getForwardedTarget(AST);
- if (--OldAS->RefCount == 0)
- OldAS->removeFromTracker(AST);
- AS->RefCount++;
+ AS->addRef();
+ OldAS->dropRef(AST);
}
return AS;
}
void setAliasSet(AliasSet *as) {
- assert(AS == 0 && "Already have an alias set!");
+ assert(!AS && "Already have an alias set!");
AS = as;
}
- void removeFromList() {
- if (NextInList) NextInList->second.PrevInList = PrevInList;
+ void eraseFromList() {
+ if (NextInList) NextInList->PrevInList = PrevInList;
*PrevInList = NextInList;
+ if (AS->PtrListEnd == &NextInList) {
+ AS->PtrListEnd = PrevInList;
+ assert(*AS->PtrListEnd == nullptr && "List not terminated right!");
+ }
+ delete this;
}
};
- HashNodePair *PtrList, **PtrListEnd; // Doubly linked list of nodes
- AliasSet *Forward; // Forwarding pointer
- AliasSet *Next, *Prev; // Doubly linked list of AliasSets
+ PointerRec *PtrList, **PtrListEnd; // Doubly linked list of nodes.
+ AliasSet *Forward; // Forwarding pointer.
- std::vector<CallSite> CallSites; // All calls & invokes in this node
+ // All instructions without a specific address in this alias set.
+ std::vector<AssertingVH<Instruction> > UnknownInsts;
// RefCount - Number of nodes pointing to this AliasSet plus the number of
// AliasSets forwarding to it.
unsigned RefCount : 28;
- /// AccessType - Keep track of whether this alias set merely refers to the
- /// locations of memory, whether it modifies the memory, or whether it does
- /// both. The lattice goes from "NoModRef" to either Refs or Mods, then to
- /// ModRef as necessary.
+ /// The kinds of access this alias set models.
///
- enum AccessType {
- NoModRef = 0, Refs = 1, // Ref = bit 1
- Mods = 2, ModRef = 3 // Mod = bit 2
+ /// We keep track of whether this alias set merely refers to the locations of
+ /// memory (and not any particular access), whether it modifies or references
+ /// the memory, or whether it does both. The lattice goes from "NoAccess" to
+ /// either RefAccess or ModAccess, then to ModRefAccess as necessary.
+ enum AccessLattice {
+ NoAccess = 0,
+ RefAccess = 1,
+ ModAccess = 2,
+ ModRefAccess = RefAccess | ModAccess
};
- unsigned AccessTy : 2;
+ unsigned Access : 2;
- /// AliasType - Keep track the relationships between the pointers in the set.
- /// Lattice goes from MustAlias to MayAlias.
+ /// The kind of alias relationship between pointers of the set.
///
- enum AliasType {
- MustAlias = 0, MayAlias = 1
+ /// These represent conservatively correct alias results between any members
+ /// of the set. We represent these independently of the values of alias
+ /// results in order to pack it into a single bit. Lattice goes from
+ /// MustAlias to MayAlias.
+ enum AliasLattice {
+ SetMustAlias = 0, SetMayAlias = 1
};
- unsigned AliasTy : 1;
+ unsigned Alias : 1;
// Volatile - True if this alias set contains volatile loads or stores.
bool Volatile : 1;
- friend class ilist_traits<AliasSet>;
- AliasSet *getPrev() const { return Prev; }
- AliasSet *getNext() const { return Next; }
- void setPrev(AliasSet *P) { Prev = P; }
- void setNext(AliasSet *N) { Next = N; }
+ void addRef() { ++RefCount; }
+ void dropRef(AliasSetTracker &AST) {
+ assert(RefCount >= 1 && "Invalid reference count detected!");
+ if (--RefCount == 0)
+ removeFromTracker(AST);
+ }
+ Instruction *getUnknownInst(unsigned i) const {
+ assert(i < UnknownInsts.size());
+ return UnknownInsts[i];
+ }
+
public:
/// Accessors...
- bool isRef() const { return AccessTy & Refs; }
- bool isMod() const { return AccessTy & Mods; }
- bool isMustAlias() const { return AliasTy == MustAlias; }
- bool isMayAlias() const { return AliasTy == MayAlias; }
+ bool isRef() const { return Access & RefAccess; }
+ bool isMod() const { return Access & ModAccess; }
+ bool isMustAlias() const { return Alias == SetMustAlias; }
+ bool isMayAlias() const { return Alias == SetMayAlias; }
// isVolatile - Return true if this alias set contains volatile loads or
// stores.
bool isVolatile() const { return Volatile; }
-
/// isForwardingAliasSet - Return true if this alias set should be ignored as
/// part of the AliasSetTracker object.
bool isForwardingAliasSet() const { return Forward; }
/// mergeSetIn - Merge the specified alias set into this alias set...
///
- void mergeSetIn(AliasSet &AS);
+ void mergeSetIn(AliasSet &AS, AliasSetTracker &AST);
// Alias Set iteration - Allow access to all of the pointer which are part of
// this alias set...
class iterator;
iterator begin() const { return iterator(PtrList); }
iterator end() const { return iterator(); }
+ bool empty() const { return PtrList == nullptr; }
- void print(std::ostream &OS) const;
+ void print(raw_ostream &OS) const;
void dump() const;
/// Define an iterator for alias sets... this is just a forward iterator.
- class iterator : public forward_iterator<HashNodePair, ptrdiff_t> {
- HashNodePair *CurNode;
+ class iterator : public std::iterator<std::forward_iterator_tag,
+ PointerRec, ptrdiff_t> {
+ PointerRec *CurNode;
public:
- iterator(HashNodePair *CN = 0) : CurNode(CN) {}
-
+ explicit iterator(PointerRec *CN = nullptr) : CurNode(CN) {}
+
bool operator==(const iterator& x) const {
return CurNode == x.CurNode;
}
bool operator!=(const iterator& x) const { return !operator==(x); }
- const iterator &operator=(const iterator &I) {
- CurNode = I.CurNode;
- return *this;
- }
-
value_type &operator*() const {
assert(CurNode && "Dereferencing AliasSet.end()!");
return *CurNode;
}
value_type *operator->() const { return &operator*(); }
-
+
+ Value *getPointer() const { return CurNode->getValue(); }
+ uint64_t getSize() const { return CurNode->getSize(); }
+ AAMDNodes getAAInfo() const { return CurNode->getAAInfo(); }
+
iterator& operator++() { // Preincrement
assert(CurNode && "Advancing past AliasSet.end()!");
- CurNode = CurNode->second.getNext();
+ CurNode = CurNode->getNext();
return *this;
}
iterator operator++(int) { // Postincrement
- iterator tmp = *this; ++*this; return tmp;
+ iterator tmp = *this; ++*this; return tmp;
}
};
private:
- // Can only be created by AliasSetTracker
- AliasSet() : PtrList(0), PtrListEnd(&PtrList), Forward(0), RefCount(0),
- AccessTy(NoModRef), AliasTy(MustAlias), Volatile(false) {
- }
- AliasSet(const AliasSet &AS) {
- // AliasSet's only get copy constructed in simple circumstances. In
- // particular, they cannot have any pointers in their list. Despite this,
- // we have to be sure to update the PtrListEnd to not point to the source
- // AliasSet's list.
- assert(AS.PtrList == 0 && "AliasSet has pointers in it!");
- PtrList = 0; PtrListEnd = &PtrList;
- Forward = AS.Forward; RefCount = AS.RefCount;
- AccessTy = AS.AccessTy; AliasTy = AS.AliasTy; Volatile = AS.Volatile;
+ // Can only be created by AliasSetTracker. Also, ilist creates one
+ // to serve as a sentinel.
+ friend struct ilist_sentinel_traits<AliasSet>;
+ AliasSet()
+ : PtrList(nullptr), PtrListEnd(&PtrList), Forward(nullptr), RefCount(0),
+ Access(NoAccess), Alias(SetMustAlias), Volatile(false) {
}
- HashNodePair *getSomePointer() const {
+ AliasSet(const AliasSet &AS) = delete;
+ void operator=(const AliasSet &AS) = delete;
+
+ PointerRec *getSomePointer() const {
return PtrList;
}
AliasSet *Dest = Forward->getForwardedTarget(AST);
if (Dest != Forward) {
- Dest->RefCount++;
- if (--Forward->RefCount == 0)
- Forward->removeFromTracker(AST);
+ Dest->addRef();
+ Forward->dropRef(AST);
Forward = Dest;
}
return Dest;
void removeFromTracker(AliasSetTracker &AST);
- void addPointer(AliasSetTracker &AST, HashNodePair &Entry, unsigned Size);
- void addCallSite(CallSite CS, AliasAnalysis &AA);
+ void addPointer(AliasSetTracker &AST, PointerRec &Entry, uint64_t Size,
+ const AAMDNodes &AAInfo,
+ bool KnownMustAlias = false);
+ void addUnknownInst(Instruction *I, AliasAnalysis &AA);
+ void removeUnknownInst(AliasSetTracker &AST, Instruction *I) {
+ bool WasEmpty = UnknownInsts.empty();
+ for (size_t i = 0, e = UnknownInsts.size(); i != e; ++i)
+ if (UnknownInsts[i] == I) {
+ UnknownInsts[i] = UnknownInsts.back();
+ UnknownInsts.pop_back();
+ --i; --e; // Revisit the moved entry.
+ }
+ if (!WasEmpty && UnknownInsts.empty())
+ dropRef(AST);
+ }
void setVolatile() { Volatile = true; }
+public:
/// aliasesPointer - Return true if the specified pointer "may" (or must)
/// alias one of the members in the set.
///
- bool aliasesPointer(const Value *Ptr, unsigned Size, AliasAnalysis &AA) const;
- bool aliasesCallSite(CallSite CS, AliasAnalysis &AA) const;
+ bool aliasesPointer(const Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo,
+ AliasAnalysis &AA) const;
+ bool aliasesUnknownInst(const Instruction *Inst, AliasAnalysis &AA) const;
};
-inline std::ostream& operator<<(std::ostream &OS, const AliasSet &AS) {
+inline raw_ostream& operator<<(raw_ostream &OS, const AliasSet &AS) {
AS.print(OS);
return OS;
}
class AliasSetTracker {
+ /// CallbackVH - A CallbackVH to arrange for AliasSetTracker to be
+ /// notified whenever a Value is deleted.
+ class ASTCallbackVH final : public CallbackVH {
+ AliasSetTracker *AST;
+ void deleted() override;
+ void allUsesReplacedWith(Value *) override;
+ public:
+ ASTCallbackVH(Value *V, AliasSetTracker *AST = nullptr);
+ ASTCallbackVH &operator=(Value *V);
+ };
+ /// ASTCallbackVHDenseMapInfo - Traits to tell DenseMap that tell us how to
+ /// compare and hash the value handle.
+ struct ASTCallbackVHDenseMapInfo : public DenseMapInfo<Value *> {};
+
AliasAnalysis &AA;
ilist<AliasSet> AliasSets;
+ typedef DenseMap<ASTCallbackVH, AliasSet::PointerRec*,
+ ASTCallbackVHDenseMapInfo>
+ PointerMapType;
+
// Map from pointers to their node
- hash_map<Value*, AliasSet::PointerRec> PointerMap;
+ PointerMapType PointerMap;
+
public:
/// AliasSetTracker ctor - Create an empty collection of AliasSets, and use
/// the specified alias analysis object to disambiguate load and store
/// addresses.
- AliasSetTracker(AliasAnalysis &aa) : AA(aa) {}
+ explicit AliasSetTracker(AliasAnalysis &aa) : AA(aa) {}
+ ~AliasSetTracker() { clear(); }
/// add methods - These methods are used to add different types of
/// instructions to the alias sets. Adding a new instruction can result in
/// These methods return true if inserting the instruction resulted in the
/// addition of a new alias set (i.e., the pointer did not alias anything).
///
+ bool add(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo); // Add a loc.
bool add(LoadInst *LI);
bool add(StoreInst *SI);
- bool add(CallSite CS); // Call/Invoke instructions
- bool add(CallInst *CI) { return add(CallSite(CI)); }
- bool add(InvokeInst *II) { return add(CallSite(II)); }
+ bool add(VAArgInst *VAAI);
bool add(Instruction *I); // Dispatch to one of the other add methods...
void add(BasicBlock &BB); // Add all instructions in basic block
void add(const AliasSetTracker &AST); // Add alias relations from another AST
-
- /// deleteValue method - This method is used to remove a pointer value from
- /// the AliasSetTracker entirely. It should be used when an instruction is
- /// deleted from the program to update the AST. If you don't use this, you
- /// would have dangling pointers to deleted instructions.
- ///
- void deleteValue(Value *PtrVal);
+ bool addUnknown(Instruction *I);
+
+ /// remove methods - These methods are used to remove all entries that might
+ /// be aliased by the specified instruction. These methods return true if any
+ /// alias sets were eliminated.
+ // Remove a location
+ bool remove(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo);
+ bool remove(LoadInst *LI);
+ bool remove(StoreInst *SI);
+ bool remove(VAArgInst *VAAI);
+ bool remove(Instruction *I);
+ void remove(AliasSet &AS);
+ bool removeUnknown(Instruction *I);
+
+ void clear();
/// getAliasSets - Return the alias sets that are active.
+ ///
const ilist<AliasSet> &getAliasSets() const { return AliasSets; }
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in. If the New argument is non-null, this method sets the value to
/// true if a new alias set is created to contain the pointer (because the
/// pointer didn't alias anything).
- AliasSet &getAliasSetForPointer(Value *P, unsigned Size, bool *New = 0);
+ AliasSet &getAliasSetForPointer(Value *P, uint64_t Size,
+ const AAMDNodes &AAInfo,
+ bool *New = nullptr);
+
+ /// getAliasSetForPointerIfExists - Return the alias set containing the
+ /// location specified if one exists, otherwise return null.
+ AliasSet *getAliasSetForPointerIfExists(const Value *P, uint64_t Size,
+ const AAMDNodes &AAInfo) {
+ return findAliasSetForPointer(P, Size, AAInfo);
+ }
+
+ /// containsPointer - Return true if the specified location is represented by
+ /// this alias set, false otherwise. This does not modify the AST object or
+ /// alias sets.
+ bool containsPointer(const Value *P, uint64_t Size,
+ const AAMDNodes &AAInfo) const;
+
+ /// Return true if the specified instruction "may" (or must) alias one of the
+ /// members in any of the sets.
+ bool containsUnknown(const Instruction *I) const;
/// getAliasAnalysis - Return the underlying alias analysis object used by
/// this tracker.
AliasAnalysis &getAliasAnalysis() const { return AA; }
+ /// deleteValue method - This method is used to remove a pointer value from
+ /// the AliasSetTracker entirely. It should be used when an instruction is
+ /// deleted from the program to update the AST. If you don't use this, you
+ /// would have dangling pointers to deleted instructions.
+ ///
+ void deleteValue(Value *PtrVal);
+
+ /// copyValue - This method should be used whenever a preexisting value in the
+ /// program is copied or cloned, introducing a new value. Note that it is ok
+ /// for clients that use this method to introduce the same value multiple
+ /// times: if the tracker already knows about a value, it will ignore the
+ /// request.
+ ///
+ void copyValue(Value *From, Value *To);
+
+
typedef ilist<AliasSet>::iterator iterator;
typedef ilist<AliasSet>::const_iterator const_iterator;
iterator begin() { return AliasSets.begin(); }
iterator end() { return AliasSets.end(); }
- void print(std::ostream &OS) const;
+ void print(raw_ostream &OS) const;
void dump() const;
private:
friend class AliasSet;
void removeAliasSet(AliasSet *AS);
- AliasSet::HashNodePair &getEntryFor(Value *V) {
- // Standard operator[], except that it returns the whole pair, not just
- // ->second.
- return *PointerMap.insert(AliasSet::HashNodePair(V,
- AliasSet::PointerRec())).first;
+ // getEntryFor - Just like operator[] on the map, except that it creates an
+ // entry for the pointer if it doesn't already exist.
+ AliasSet::PointerRec &getEntryFor(Value *V) {
+ AliasSet::PointerRec *&Entry = PointerMap[ASTCallbackVH(V, this)];
+ if (!Entry)
+ Entry = new AliasSet::PointerRec(V);
+ return *Entry;
}
- AliasSet &addPointer(Value *P, unsigned Size, AliasSet::AccessType E,
+ AliasSet &addPointer(Value *P, uint64_t Size, const AAMDNodes &AAInfo,
+ AliasSet::AccessLattice E,
bool &NewSet) {
NewSet = false;
- AliasSet &AS = getAliasSetForPointer(P, Size, &NewSet);
- AS.AccessTy |= E;
+ AliasSet &AS = getAliasSetForPointer(P, Size, AAInfo, &NewSet);
+ AS.Access |= E;
return AS;
}
- AliasSet *findAliasSetForPointer(const Value *Ptr, unsigned Size);
+ AliasSet *findAliasSetForPointer(const Value *Ptr, uint64_t Size,
+ const AAMDNodes &AAInfo);
- AliasSet *findAliasSetForCallSite(CallSite CS);
+ AliasSet *findAliasSetForUnknownInst(Instruction *Inst);
};
-inline std::ostream& operator<<(std::ostream &OS, const AliasSetTracker &AST) {
+inline raw_ostream& operator<<(raw_ostream &OS, const AliasSetTracker &AST) {
AST.print(OS);
return OS;
}
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