Make the aliassettracker much more precise by actually tracking size

information for various accesses.  What a concept.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5647 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-02-26 22:11:00 +00:00
parent cd4d41cd4f
commit 31a9d185bf
2 changed files with 53 additions and 33 deletions

View File

@ -29,12 +29,19 @@ class AliasSet {
class PointerRec {
HashNodePair *NextInList;
AliasSet *AS;
unsigned Size;
public:
PointerRec() : NextInList(0), AS(0) {}
PointerRec() : NextInList(0), AS(0), Size(0) {}
HashNodePair *getNext() const { return NextInList; }
bool hasAliasSet() const { return AS != 0; }
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) {
@ -87,7 +94,7 @@ class AliasSet {
unsigned AliasTy : 1;
/// Define an iterator for alias sets... this is just a forward iterator.
class iterator : public forward_iterator<Value*, ptrdiff_t> {
class iterator : public forward_iterator<HashNodePair, ptrdiff_t> {
HashNodePair *CurNode;
public:
iterator(HashNodePair *CN = 0) : CurNode(CN) {}
@ -102,11 +109,11 @@ class AliasSet {
return *this;
}
value_type operator*() const {
value_type &operator*() const {
assert(CurNode && "Dereferencing AliasSet.end()!");
return CurNode->first;
return *CurNode;
}
value_type operator->() const { return operator*(); }
value_type *operator->() const { return &operator*(); }
iterator& operator++() { // Preincrement
assert(CurNode && "Advancing past AliasSet.end()!");
@ -148,8 +155,8 @@ private:
AliasSet() : PtrListHead(0), PtrListTail(0), Forward(0), RefCount(0),
AccessTy(NoModRef), AliasTy(MustAlias) {
}
Value *getSomePointer() const {
return PtrListHead ? PtrListHead->first : 0;
HashNodePair *getSomePointer() const {
return PtrListHead ? PtrListHead : 0;
}
/// getForwardedTarget - Return the real alias set this represents. If this
@ -170,13 +177,13 @@ private:
void removeFromTracker(AliasSetTracker &AST);
void addPointer(AliasSetTracker &AST, HashNodePair &Entry);
void addPointer(AliasSetTracker &AST, HashNodePair &Entry, unsigned Size);
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 aliasesPointer(const Value *Ptr, unsigned Size, AliasAnalysis &AA) const;
bool aliasesCallSite(CallSite CS, AliasAnalysis &AA) const;
};
@ -219,7 +226,7 @@ public:
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in...
AliasSet &getAliasSetForPointer(Value *P);
AliasSet &getAliasSetForPointer(Value *P, unsigned Size);
/// getAliasAnalysis - Return the underlying alias analysis object used by
/// this tracker.
@ -248,11 +255,11 @@ private:
AliasSet::PointerRec())).first;
}
void addPointer(Value *P, AliasSet::AccessType E) {
AliasSet &AS = getAliasSetForPointer(P);
void addPointer(Value *P, unsigned Size, AliasSet::AccessType E) {
AliasSet &AS = getAliasSetForPointer(P, Size);
AS.AccessTy |= E;
}
AliasSet *findAliasSetForPointer(const Value *Ptr);
AliasSet *findAliasSetForPointer(const Value *Ptr, unsigned Size);
AliasSet *findAliasSetForCallSite(CallSite CS);
};

View File

@ -10,11 +10,10 @@
#include "llvm/iOther.h"
#include "llvm/iTerminators.h"
#include "llvm/Pass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/InstIterator.h"
// FIXME: This should keep sizes associated with pointers!
/// mergeSetIn - Merge the specified alias set into this alias set...
///
void AliasSet::mergeSetIn(AliasSet &AS) {
@ -54,17 +53,25 @@ void AliasSet::removeFromTracker(AliasSetTracker &AST) {
AST.removeAliasSet(this);
}
void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry){
void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
unsigned Size) {
assert(!Entry.second.hasAliasSet() && "Entry already in set!");
AliasAnalysis &AA = AST.getAliasAnalysis();
if (isMustAlias()) // Check to see if we have to downgrade to _may_ alias
if (Value *V = getSomePointer())
if (AA.alias(V, ~0, Entry.first, ~0) == AliasAnalysis::MayAlias)
if (HashNodePair *P = getSomePointer()) {
AliasAnalysis::AliasResult Result =
AA.alias(P->first, P->second.getSize(), Entry.first, Size);
if (Result == AliasAnalysis::MayAlias)
AliasTy = MayAlias;
else // First entry of must alias must have maximum size!
P->second.updateSize(Size);
assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
}
Entry.second.setAliasSet(this);
Entry.second.updateSize(Size);
// Add it to the end of the list...
if (PtrListTail)
@ -77,27 +84,28 @@ void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry){
void AliasSet::addCallSite(CallSite CS) {
CallSites.push_back(CS);
AliasTy = MayAlias; // FIXME: Too conservative
AliasTy = MayAlias; // FIXME: Too conservative?
}
/// aliasesPointer - Return true if the specified pointer "may" (or must)
/// alias one of the members in the set.
///
bool AliasSet::aliasesPointer(const Value *Ptr, AliasAnalysis &AA) const {
bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
AliasAnalysis &AA) const {
if (AliasTy == MustAlias) {
assert(CallSites.empty() && "Illegal must alias set!");
// If this is a set of MustAliases, only check to see if the pointer aliases
// SOME value in the set...
Value *SomePtr = getSomePointer();
HashNodePair *SomePtr = getSomePointer();
assert(SomePtr && "Empty must-alias set??");
return AA.alias(SomePtr, ~0, Ptr, ~0);
return AA.alias(SomePtr->first, SomePtr->second.getSize(), Ptr, Size);
}
// If this is a may-alias set, we have to check all of the pointers in the set
// to be sure it doesn't alias the set...
for (iterator I = begin(), E = end(); I != E; ++I)
if (AA.alias(Ptr, ~0, *I, ~0))
if (AA.alias(Ptr, Size, I->first, I->second.getSize()))
return true;
// Check the call sites list and invoke list...
@ -118,10 +126,11 @@ bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
/// instruction referring to the pointer into. If there are multiple alias sets
/// that may alias the pointer, merge them together and return the unified set.
///
AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr) {
AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
unsigned Size) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesPointer(Ptr, AA)) {
if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
if (FoundSet == 0) { // If this is the first alias set ptr can go into...
FoundSet = I; // Remember it.
} else { // Otherwise, we must merge the sets...
@ -151,31 +160,34 @@ AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in...
AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer) {
AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size){
AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
// Check to see if the pointer is already known...
if (Entry.second.hasAliasSet()) {
if (Entry.second.hasAliasSet() && Size <= Entry.second.getSize()) {
// Return the set!
return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
} else if (AliasSet *AS = findAliasSetForPointer(Pointer)) {
} else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
// Add it to the alias set it aliases...
AS->addPointer(*this, Entry);
AS->addPointer(*this, Entry, Size);
return *AS;
} else {
// Otherwise create a new alias set to hold the loaded pointer...
AliasSets.push_back(AliasSet());
AliasSets.back().addPointer(*this, Entry);
AliasSets.back().addPointer(*this, Entry, Size);
return AliasSets.back();
}
}
void AliasSetTracker::add(LoadInst *LI) {
addPointer(LI->getOperand(0), AliasSet::Refs);
addPointer(LI->getOperand(0),
AA.getTargetData().getTypeSize(LI->getType()), AliasSet::Refs);
}
void AliasSetTracker::add(StoreInst *SI) {
addPointer(SI->getOperand(1), AliasSet::Mods);
addPointer(SI->getOperand(1),
AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()),
AliasSet::Mods);
}
void AliasSetTracker::add(CallSite CS) {
@ -221,7 +233,8 @@ void AliasSet::print(std::ostream &OS) const {
OS << "Pointers: ";
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I != begin()) OS << ", ";
WriteAsOperand(OS, *I);
WriteAsOperand(OS << "(", I->first);
OS << ", " << I->second.getSize() << ")";
}
}
if (!CallSites.empty()) {