[llvm-commits] CVS: llvm/include/llvm/Analysis/AliasSetTracker.h
Chris Lattner
lattner at cs.uiuc.edu
Mon Feb 24 14:39:00 PST 2003
Changes in directory llvm/include/llvm/Analysis:
AliasSetTracker.h updated: 1.1 -> 1.2
---
Log message:
This is a substantial rewrite of the AliasSetTracker class which now uses
a union-find based algorithm, is significantly faster, and is more general.
It will also scale to handle call instructions correctly, which is a nice
added bonus.
This includes a new pass -print-alias-sets which can be used to show how
alias sets are formed for a particular analysis.
---
Diffs of the changes:
Index: llvm/include/llvm/Analysis/AliasSetTracker.h
diff -u llvm/include/llvm/Analysis/AliasSetTracker.h:1.1 llvm/include/llvm/Analysis/AliasSetTracker.h:1.2
--- llvm/include/llvm/Analysis/AliasSetTracker.h:1.1 Thu Sep 26 16:49:04 2002
+++ llvm/include/llvm/Analysis/AliasSetTracker.h Mon Feb 24 14:37:52 2003
@@ -10,80 +10,194 @@
#ifndef LLVM_ANALYSIS_ALIASSETTRACKER_H
#define LLVM_ANALYSIS_ALIASSETTRACKER_H
-#include <vector>
+#include "llvm/Support/CallSite.h"
+#include "Support/iterator"
+#include "Support/hash_map"
+#include "Support/ilist"
class AliasAnalysis;
class LoadInst;
class StoreInst;
-class CallInst;
-class InvokeInst;
-class Value;
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:
+
+ struct PointerRec;
+ typedef std::pair<Value* const, PointerRec> HashNodePair;
+
+ class PointerRec {
+ HashNodePair *NextInList;
+ AliasSet *AS;
+ public:
+ PointerRec() : NextInList(0), AS(0) {}
+
+ HashNodePair *getNext() const { return NextInList; }
+ bool hasAliasSet() const { return AS != 0; }
+
+ 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++;
+ }
+ return AS;
+ }
+
+ void setAliasSet(AliasSet *as) {
+ assert(AS == 0 && "Already have an alias set!");
+ AS = as;
+ }
+ void setTail(HashNodePair *T) {
+ assert(NextInList == 0 && "Already have tail!");
+ NextInList = T;
+ }
+ };
+
+ HashNodePair *PtrListHead, *PtrListTail; // Singly 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 : 29;
+
/// 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 neccesary.
///
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;
-public:
- /// Accessors...
- enum AccessType getAccessType() const { return AccessTy; }
- enum AliasType getAliasType() const { return AliasTy; }
+ unsigned AliasTy : 1;
- // 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.
+ /// Define an iterator for alias sets... this is just a forward iterator.
+ class iterator : public forward_iterator<Value*, 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->first;
+ }
+ value_type operator->() const { return operator*(); }
+
+ 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;
+ }
+ };
- /// 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;
+ 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; }
+
+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; }
/// mergeSetIn - Merge the specified alias set into this alias set...
///
- void mergeSetIn(const AliasSet &AS);
+ void mergeSetIn(AliasSet &AS);
- 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; }
+ // Alias Set iteration - Allow access to all of the pointer which are part of
+ // this alias set...
+ iterator begin() const { return iterator(PtrListHead); }
+ iterator end() const { return iterator(); }
+
+ void print(std::ostream &OS) const;
+ void dump() const;
private:
- AliasSet() : AliasTy(MustAlias) {} // Can only be created by AliasSetTracker
- void updateAccessType();
- Value *getSomePointer() const;
+ // Can only be created by AliasSetTracker
+ AliasSet() : PtrListHead(0), PtrListTail(0), Forward(0), RefCount(0),
+ AccessTy(NoModRef), AliasTy(MustAlias) {
+ }
+ Value *getSomePointer() const {
+ return PtrListHead ? PtrListHead->first : 0;
+ }
+
+ /// 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->RefCount++;
+ if (--Forward->RefCount == 0)
+ Forward->removeFromTracker(AST);
+ Forward = Dest;
+ }
+ return Dest;
+ }
+
+ void removeFromTracker(AliasSetTracker &AST);
+
+ void addPointer(AliasSetTracker &AST, HashNodePair &Entry);
+ void addCallSite(CallSite CS);
+
+ /// aliasesPointer - Return true if the specified pointer "may" (or must)
+ /// alias one of the members in the set.
+ ///
+ bool aliasesPointer(const Value *Ptr, 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:
@@ -95,15 +209,57 @@
///
void add(LoadInst *LI);
void add(StoreInst *SI);
- void add(CallInst *CI);
- void add(InvokeInst *II);
+ void add(CallSite CS); // Call/Invoke instructions
+ void add(CallInst *CI) { add(CallSite(CI)); }
+ void add(InvokeInst *II) { add(CallSite(II)); }
+ void add(Instruction *I); // Dispatch to one of the other add methods...
/// 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...
+ AliasSet &getAliasSetForPointer(Value *P);
+
+ /// getAliasAnalysis - Return the underlying alias analysis object used by
+ /// this tracker.
+ AliasAnalysis &getAliasAnalysis() const { return AA; }
+
+ 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:
+ 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;
+ }
+
+ void addPointer(Value *P, AliasSet::AccessType E) {
+ AliasSet &AS = getAliasSetForPointer(P);
+ AS.AccessTy |= E;
+ }
AliasSet *findAliasSetForPointer(const Value *Ptr);
- void mergeAllSets();
+
+ AliasSet *findAliasSetForCallSite(CallSite CS);
};
+
+inline std::ostream& operator<<(std::ostream &OS, const AliasSetTracker &AST) {
+ AST.print(OS);
+ return OS;
+}
#endif
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