//===- 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 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 <vector>
+#include "llvm/Support/CallSite.h"
+#include "llvm/ADT/iterator"
+#include "llvm/ADT/hash_map"
+#include "llvm/ADT/ilist"
+
+namespace llvm {
+
class AliasAnalysis;
class LoadInst;
class StoreInst;
-class CallInst;
-class InvokeInst;
-class Value;
+class FreeInst;
class AliasSetTracker;
+class AliasSet;
class AliasSet {
friend class AliasSetTracker;
- std::vector<LoadInst*> Loads;
- std::vector<StoreInst*> Stores;
- std::vector<CallInst*> Calls;
- std::vector<InvokeInst*> Invokes;
-public:
+
+ class PointerRec;
+ typedef std::pair<Value* const, PointerRec> HashNodePair;
+
+ class PointerRec {
+ HashNodePair **PrevInList, *NextInList;
+ AliasSet *AS;
+ unsigned Size;
+ public:
+ PointerRec() : PrevInList(0), NextInList(0), AS(0), Size(0) {}
+
+ HashNodePair *getNext() const { return NextInList; }
+ bool hasAliasSet() const { return AS != 0; }
+
+ HashNodePair** setPrevInList(HashNodePair **PIL) {
+ PrevInList = PIL;
+ return &NextInList;
+ }
+
+ void updateSize(unsigned NewSize) {
+ if (NewSize > Size) Size = NewSize;
+ }
+
+ unsigned getSize() const { return Size; }
+
+ AliasSet *getAliasSet(AliasSetTracker &AST) {
+ assert(AS && "No AliasSet yet!");
+ if (AS->Forward) {
+ AliasSet *OldAS = AS;
+ AS = OldAS->getForwardedTarget(AST);
+ AS->addRef();
+ OldAS->dropRef(AST);
+ }
+ return AS;
+ }
+
+ void setAliasSet(AliasSet *as) {
+ assert(AS == 0 && "Already have an alias set!");
+ AS = as;
+ }
+
+ void removeFromList() {
+ if (NextInList) NextInList->second.PrevInList = PrevInList;
+ *PrevInList = NextInList;
+ if (AS->PtrListEnd == &NextInList) {
+ AS->PtrListEnd = PrevInList;
+ assert(*AS->PtrListEnd == 0 && "List not terminated right!");
+ }
+ }
+ };
+
+ HashNodePair *PtrList, **PtrListEnd; // Doubly linked list of nodes
+ AliasSet *Forward; // Forwarding pointer
+ AliasSet *Next, *Prev; // Doubly linked list of AliasSets
+
+ std::vector<CallSite> CallSites; // All calls & invokes in this node
+
+ // 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 "None" (alias set not present) to either Refs
- /// or Mods, then to ModRef as neccesary.
+ /// both. The lattice goes from "NoModRef" to either Refs or Mods, then to
+ /// ModRef as necessary.
///
enum AccessType {
- Refs, Mods, ModRef
+ NoModRef = 0, Refs = 1, // Ref = bit 1
+ Mods = 2, ModRef = 3 // Mod = bit 2
};
+ unsigned AccessTy : 2;
/// AliasType - Keep track the relationships between the pointers in the set.
/// Lattice goes from MustAlias to MayAlias.
///
enum AliasType {
- MustAlias, MayAlias
+ MustAlias = 0, MayAlias = 1
};
-private:
- enum AccessType AccessTy;
- enum AliasType AliasTy;
+ unsigned AliasTy : 1;
+
+ // Volatile - True if this alias set contains volatile loads or stores.
+ bool Volatile : 1;
+
+ friend struct 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);
+ }
+
public:
/// Accessors...
- enum AccessType getAccessType() const { return AccessTy; }
- enum AliasType getAliasType() const { return AliasTy; }
+ bool isRef() const { return AccessTy & Refs; }
+ bool isMod() const { return AccessTy & Mods; }
+ bool isMustAlias() const { return AliasTy == MustAlias; }
+ bool isMayAlias() const { return AliasTy == MayAlias; }
- // TODO: in the future, add a fixed size (4? 2?) cache of pointers that we
- // know are in the alias set, to cut down time answering "pointeraliasesset"
- // queries.
+ // isVolatile - Return true if this alias set contains volatile loads or
+ // stores.
+ bool isVolatile() const { return Volatile; }
- /// pointerAliasesSet - Return true if the specified pointer "may" (or must)
- /// alias one of the members in the set.
- ///
- bool pointerAliasesSet(const Value *Ptr, AliasAnalysis &AA) const;
+ /// 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(const 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 == 0; }
+
+ void print(std::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;
+ public:
+ iterator(HashNodePair *CN = 0) : 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*(); }
- const std::vector<LoadInst*> &getLoads() const { return Loads; }
- const std::vector<StoreInst*> &getStores() const { return Stores; }
- const std::vector<CallInst*> &getCalls() const { return Calls; }
- const std::vector<InvokeInst*> &getInvokes() const { return Invokes; }
+ Value *getPointer() const { return CurNode->first; }
+ unsigned getSize() const { return CurNode->second.getSize(); }
+
+ iterator& operator++() { // Preincrement
+ assert(CurNode && "Advancing past AliasSet.end()!");
+ CurNode = CurNode->second.getNext();
+ return *this;
+ }
+ iterator operator++(int) { // Postincrement
+ iterator tmp = *this; ++*this; return tmp;
+ }
+ };
private:
- AliasSet() : AliasTy(MustAlias) {} // Can only be created by AliasSetTracker
- void updateAccessType();
- Value *getSomePointer() const;
+ // 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) {
+ assert(0 && "Copy ctor called!?!?!");
+ abort();
+ }
+
+ HashNodePair *getSomePointer() const {
+ return PtrList;
+ }
+
+ /// getForwardedTarget - Return the real alias set this represents. If this
+ /// has been merged with another set and is forwarding, return the ultimate
+ /// destination set. This also implements the union-find collapsing as well.
+ AliasSet *getForwardedTarget(AliasSetTracker &AST) {
+ if (!Forward) return this;
+
+ AliasSet *Dest = Forward->getForwardedTarget(AST);
+ if (Dest != Forward) {
+ Dest->addRef();
+ Forward->dropRef(AST);
+ Forward = Dest;
+ }
+ return Dest;
+ }
+
+ void removeFromTracker(AliasSetTracker &AST);
+
+ void addPointer(AliasSetTracker &AST, HashNodePair &Entry, unsigned Size,
+ bool KnownMustAlias = false);
+ void addCallSite(CallSite CS, AliasAnalysis &AA);
+ void setVolatile() { Volatile = true; }
+
+ /// 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;
};
+inline std::ostream& operator<<(std::ostream &OS, const AliasSet &AS) {
+ AS.print(OS);
+ return OS;
+}
+
class AliasSetTracker {
AliasAnalysis &AA;
- std::vector<AliasSet> AliasSets;
+ ilist<AliasSet> AliasSets;
+
+ // Map from pointers to their node
+ hash_map<Value*, AliasSet::PointerRec> 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) {}
-
/// add methods - These methods are used to add different types of
/// instructions to the alias sets. Adding a new instruction can result in
/// one of three actions happening:
/// 3. If the instruction aliases multiple sets, merge the sets, and add
/// the instruction to the result.
///
- void add(LoadInst *LI);
- void add(StoreInst *SI);
- void add(CallInst *CI);
- void add(InvokeInst *II);
+ /// 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, unsigned Size); // Add a location
+ bool add(LoadInst *LI);
+ bool add(StoreInst *SI);
+ bool add(FreeInst *FI);
+ 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(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
+
+ /// 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.
+ bool remove(Value *Ptr, unsigned Size); // Remove a location
+ bool remove(LoadInst *LI);
+ bool remove(StoreInst *SI);
+ bool remove(FreeInst *FI);
+ bool remove(CallSite CS);
+ bool remove(CallInst *CI) { return remove(CallSite(CI)); }
+ bool remove(InvokeInst *II) { return remove(CallSite(II)); }
+ bool remove(Instruction *I);
+ void remove(AliasSet &AS);
+
+ void clear() {
+ PointerMap.clear();
+ AliasSets.clear();
+ }
/// getAliasSets - Return the alias sets that are active.
- const std::vector<AliasSet> &getAliasSets() const { return AliasSets; }
+ ///
+ 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);
+
+ /// getAliasSetForPointerIfExists - Return the alias set containing the
+ /// location specified if one exists, otherwise return null.
+ AliasSet *getAliasSetForPointerIfExists(Value *P, unsigned Size) {
+ return findAliasSetForPointer(P, Size);
+ }
+
+ /// 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(Value *P, unsigned Size) 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;
+
+ const_iterator begin() const { return AliasSets.begin(); }
+ const_iterator end() const { return AliasSets.end(); }
+
+ iterator begin() { return AliasSets.begin(); }
+ iterator end() { return AliasSets.end(); }
+
+ void print(std::ostream &OS) const;
+ void dump() const;
private:
- AliasSet *findAliasSetForPointer(const Value *Ptr);
- void mergeAllSets();
+ 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;
+ }
+
+ AliasSet &addPointer(Value *P, unsigned Size, AliasSet::AccessType E,
+ bool &NewSet) {
+ NewSet = false;
+ AliasSet &AS = getAliasSetForPointer(P, Size, &NewSet);
+ AS.AccessTy |= E;
+ return AS;
+ }
+ AliasSet *findAliasSetForPointer(const Value *Ptr, unsigned Size);
+
+ AliasSet *findAliasSetForCallSite(CallSite CS);
};
+inline std::ostream& operator<<(std::ostream &OS, const AliasSetTracker &AST) {
+ AST.print(OS);
+ return OS;
+}
+
+} // End llvm namespace
+
#endif
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