//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
//
+// 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 implements the AliasSetTracker and AliasSet classes.
-//
+//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
-#include "llvm/iTerminators.h"
+#include "llvm/Instructions.h"
#include "llvm/Pass.h"
+#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/InstIterator.h"
+#include <iostream>
+using namespace llvm;
-/// mergeSetIn - Merge the specified alias set into this alias set...
+/// mergeSetIn - Merge the specified alias set into this alias set.
///
-void AliasSet::mergeSetIn(AliasSet &AS) {
+void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
assert(!AS.Forward && "Alias set is already forwarding!");
assert(!Forward && "This set is a forwarding set!!");
AccessTy |= AS.AccessTy;
AliasTy |= AS.AliasTy;
+ if (AliasTy == MustAlias) {
+ // Check that these two merged sets really are must aliases. Since both
+ // used to be must-alias sets, we can just check any pointer from each set
+ // for aliasing.
+ AliasAnalysis &AA = AST.getAliasAnalysis();
+ HashNodePair *L = getSomePointer();
+ HashNodePair *R = AS.getSomePointer();
+
+ // If the pointers are not a must-alias pair, this set becomes a may alias.
+ if (AA.alias(L->first, L->second.getSize(), R->first, R->second.getSize())
+ != AliasAnalysis::MustAlias)
+ AliasTy = MayAlias;
+ }
+
if (CallSites.empty()) { // Merge call sites...
if (!AS.CallSites.empty())
std::swap(CallSites, AS.CallSites);
CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
AS.CallSites.clear();
}
-
- // FIXME: If AS's refcount is zero, nuke it now...
- assert(RefCount != 0);
AS.Forward = this; // Forward across AS now...
- RefCount++; // AS is now pointing to us...
+ addRef(); // AS is now pointing to us...
// Merge the list of constituent pointers...
- PtrListTail->second.setTail(AS.PtrListHead);
- PtrListTail = AS.PtrListTail;
- AS.PtrListHead = AS.PtrListTail = 0;
+ if (AS.PtrList) {
+ *PtrListEnd = AS.PtrList;
+ AS.PtrList->second.setPrevInList(PtrListEnd);
+ PtrListEnd = AS.PtrListEnd;
+
+ AS.PtrList = 0;
+ AS.PtrListEnd = &AS.PtrList;
+ assert(*AS.PtrListEnd == 0 && "End of list is not null?");
+ }
}
void AliasSetTracker::removeAliasSet(AliasSet *AS) {
+ if (AliasSet *Fwd = AS->Forward) {
+ Fwd->dropRef(*this);
+ AS->Forward = 0;
+ }
AliasSets.erase(AS);
}
}
void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
- unsigned Size) {
+ unsigned Size, bool KnownMustAlias) {
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
+ // Check to see if we have to downgrade to _may_ alias.
+ if (isMustAlias() && !KnownMustAlias)
if (HashNodePair *P = getSomePointer()) {
+ AliasAnalysis &AA = AST.getAliasAnalysis();
AliasAnalysis::AliasResult Result =
AA.alias(P->first, P->second.getSize(), Entry.first, Size);
if (Result == AliasAnalysis::MayAlias)
Entry.second.updateSize(Size);
// Add it to the end of the list...
- if (PtrListTail)
- PtrListTail->second.setTail(&Entry);
- else
- PtrListHead = &Entry;
- PtrListTail = &Entry;
- RefCount++; // Entry points to alias set...
+ assert(*PtrListEnd == 0 && "End of list is not null?");
+ *PtrListEnd = &Entry;
+ PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
+ assert(*PtrListEnd == 0 && "End of list is not null?");
+ addRef(); // Entry points to alias set...
}
-void AliasSet::addCallSite(CallSite CS) {
+void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
CallSites.push_back(CS);
- AliasTy = MayAlias; // FIXME: Too conservative?
+
+ if (Function *F = CS.getCalledFunction()) {
+ AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS);
+ if (Behavior == AliasAnalysis::DoesNotAccessMemory)
+ return;
+ else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
+ AliasTy = MayAlias;
+ AccessTy |= Refs;
+ return;
+ }
+ }
+
+ // FIXME: This should use mod/ref information to make this not suck so bad
+ AliasTy = MayAlias;
+ AccessTy = ModRef;
}
/// aliasesPointer - Return true if the specified pointer "may" (or must)
// 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, Size, I->first, I->second.getSize()))
+ if (AA.alias(Ptr, Size, I.getPointer(), I.getSize()))
return true;
// Check the call sites list and invoke list...
- if (!CallSites.empty())
- // FIXME: this is pessimistic!
- return true;
+ if (!CallSites.empty()) {
+ if (AA.hasNoModRefInfoForCalls())
+ return true;
+
+ for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+ if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size)
+ != AliasAnalysis::NoModRef)
+ return true;
+ }
return false;
}
bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
- // FIXME: Too conservative!
- return true;
+ if (Function *F = CS.getCalledFunction())
+ if (AA.doesNotAccessMemory(F))
+ return false;
+
+ if (AA.hasNoModRefInfoForCalls())
+ return true;
+
+ for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+ if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef ||
+ AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef)
+ return true;
+
+ for (iterator I = begin(), E = end(); I != E; ++I)
+ if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) !=
+ AliasAnalysis::NoModRef)
+ return true;
+
+ return false;
}
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
- if (FoundSet == 0) { // If this is the first alias set ptr can go into...
+ 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...
- FoundSet->mergeSetIn(*I); // Merge in contents...
+ } else { // Otherwise, we must merge the sets.
+ FoundSet->mergeSetIn(*I, *this); // Merge in contents.
}
}
return FoundSet;
}
+/// 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 AliasSetTracker::containsPointer(Value *Ptr, unsigned Size) const {
+ for (const_iterator I = begin(), E = end(); I != E; ++I)
+ if (!I->Forward && I->aliasesPointer(Ptr, Size, AA))
+ return true;
+ return false;
+}
+
+
+
AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesCallSite(CS, AA)) {
- if (FoundSet == 0) { // If this is the first alias set ptr can go into...
+ if (FoundSet == 0) { // If this is the first alias set ptr can go into.
FoundSet = I; // Remember it.
- } else if (!I->Forward) { // Otherwise, we must merge the sets...
- FoundSet->mergeSetIn(*I); // Merge in contents...
+ } else if (!I->Forward) { // Otherwise, we must merge the sets.
+ FoundSet->mergeSetIn(*I, *this); // Merge in contents.
}
}
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in...
-AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size){
+AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size,
+ bool *New) {
AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
// Check to see if the pointer is already known...
- if (Entry.second.hasAliasSet() && Size <= Entry.second.getSize()) {
+ if (Entry.second.hasAliasSet()) {
+ Entry.second.updateSize(Size);
// Return the set!
return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
} else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
AS->addPointer(*this, Entry, Size);
return *AS;
} else {
+ if (New) *New = true;
// Otherwise create a new alias set to hold the loaded pointer...
- AliasSets.push_back(AliasSet());
+ AliasSets.push_back(new AliasSet());
AliasSets.back().addPointer(*this, Entry, Size);
return AliasSets.back();
}
}
-void AliasSetTracker::add(LoadInst *LI) {
- addPointer(LI->getOperand(0),
- AA.getTargetData().getTypeSize(LI->getType()), AliasSet::Refs);
+bool AliasSetTracker::add(Value *Ptr, unsigned Size) {
+ bool NewPtr;
+ addPointer(Ptr, Size, AliasSet::NoModRef, NewPtr);
+ return NewPtr;
+}
+
+
+bool AliasSetTracker::add(LoadInst *LI) {
+ bool NewPtr;
+ AliasSet &AS = addPointer(LI->getOperand(0),
+ AA.getTargetData().getTypeSize(LI->getType()),
+ AliasSet::Refs, NewPtr);
+ if (LI->isVolatile()) AS.setVolatile();
+ return NewPtr;
}
-void AliasSetTracker::add(StoreInst *SI) {
- addPointer(SI->getOperand(1),
- AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()),
- AliasSet::Mods);
+bool AliasSetTracker::add(StoreInst *SI) {
+ bool NewPtr;
+ Value *Val = SI->getOperand(0);
+ AliasSet &AS = addPointer(SI->getOperand(1),
+ AA.getTargetData().getTypeSize(Val->getType()),
+ AliasSet::Mods, NewPtr);
+ if (SI->isVolatile()) AS.setVolatile();
+ return NewPtr;
}
-void AliasSetTracker::add(CallSite CS) {
+bool AliasSetTracker::add(FreeInst *FI) {
+ bool NewPtr;
+ AliasSet &AS = addPointer(FI->getOperand(0), ~0,
+ AliasSet::Mods, NewPtr);
+
+ // Free operations are volatile ops (cannot be moved).
+ AS.setVolatile();
+ return NewPtr;
+}
+
+
+bool AliasSetTracker::add(CallSite CS) {
+ if (Function *F = CS.getCalledFunction())
+ if (AA.doesNotAccessMemory(F))
+ return true; // doesn't alias anything
+
AliasSet *AS = findAliasSetForCallSite(CS);
if (!AS) {
- AliasSets.push_back(AliasSet());
+ AliasSets.push_back(new AliasSet());
AS = &AliasSets.back();
+ AS->addCallSite(CS, AA);
+ return true;
+ } else {
+ AS->addCallSite(CS, AA);
+ return false;
}
- AS->addCallSite(CS);
}
-void AliasSetTracker::add(Instruction *I) {
+bool AliasSetTracker::add(Instruction *I) {
// Dispatch to one of the other add methods...
if (LoadInst *LI = dyn_cast<LoadInst>(I))
- add(LI);
+ return add(LI);
else if (StoreInst *SI = dyn_cast<StoreInst>(I))
- add(SI);
+ return add(SI);
else if (CallInst *CI = dyn_cast<CallInst>(I))
- add(CI);
+ return add(CI);
else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
- add(II);
+ return add(II);
+ else if (FreeInst *FI = dyn_cast<FreeInst>(I))
+ return add(FI);
+ return true;
+}
+
+void AliasSetTracker::add(BasicBlock &BB) {
+ for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
+ add(I);
+}
+
+void AliasSetTracker::add(const AliasSetTracker &AST) {
+ assert(&AA == &AST.AA &&
+ "Merging AliasSetTracker objects with different Alias Analyses!");
+
+ // Loop over all of the alias sets in AST, adding the pointers contained
+ // therein into the current alias sets. This can cause alias sets to be
+ // merged together in the current AST.
+ for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I)
+ if (!I->Forward) { // Ignore forwarding alias sets
+ AliasSet &AS = const_cast<AliasSet&>(*I);
+
+ // If there are any call sites in the alias set, add them to this AST.
+ for (unsigned i = 0, e = AS.CallSites.size(); i != e; ++i)
+ add(AS.CallSites[i]);
+
+ // Loop over all of the pointers in this alias set...
+ AliasSet::iterator I = AS.begin(), E = AS.end();
+ bool X;
+ for (; I != E; ++I)
+ addPointer(I.getPointer(), I.getSize(),
+ (AliasSet::AccessType)AS.AccessTy, X);
+ }
+}
+
+/// remove - Remove the specified (potentially non-empty) alias set from the
+/// tracker.
+void AliasSetTracker::remove(AliasSet &AS) {
+ bool SetDead;
+ do {
+ AliasSet::iterator I = AS.begin();
+ Value *Ptr = I.getPointer(); ++I;
+
+ // deleteValue will delete the set automatically when the last pointer
+ // reference is destroyed. "Predict" when this will happen.
+ SetDead = I == AS.end();
+ deleteValue(Ptr); // Delete all of the pointers from the set
+ } while (!SetDead);
+}
+
+bool AliasSetTracker::remove(Value *Ptr, unsigned Size) {
+ AliasSet *AS = findAliasSetForPointer(Ptr, Size);
+ if (!AS) return false;
+ remove(*AS);
+ return true;
+}
+
+bool AliasSetTracker::remove(LoadInst *LI) {
+ unsigned Size = AA.getTargetData().getTypeSize(LI->getType());
+ AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size);
+ if (!AS) return false;
+ remove(*AS);
+ return true;
+}
+
+bool AliasSetTracker::remove(StoreInst *SI) {
+ unsigned Size = AA.getTargetData().getTypeSize(SI->getOperand(0)->getType());
+ AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size);
+ if (!AS) return false;
+ remove(*AS);
+ return true;
+}
+
+bool AliasSetTracker::remove(FreeInst *FI) {
+ AliasSet *AS = findAliasSetForPointer(FI->getOperand(0), ~0);
+ if (!AS) return false;
+ remove(*AS);
+ return true;
+}
+
+bool AliasSetTracker::remove(CallSite CS) {
+ if (Function *F = CS.getCalledFunction())
+ if (AA.doesNotAccessMemory(F))
+ return false; // doesn't alias anything
+
+ AliasSet *AS = findAliasSetForCallSite(CS);
+ if (!AS) return false;
+ remove(*AS);
+ return true;
+}
+
+bool AliasSetTracker::remove(Instruction *I) {
+ // Dispatch to one of the other remove methods...
+ if (LoadInst *LI = dyn_cast<LoadInst>(I))
+ return remove(LI);
+ else if (StoreInst *SI = dyn_cast<StoreInst>(I))
+ return remove(SI);
+ else if (CallInst *CI = dyn_cast<CallInst>(I))
+ return remove(CI);
+ else if (FreeInst *FI = dyn_cast<FreeInst>(I))
+ return remove(FI);
+ return true;
}
+
+// 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 AliasSetTracker::deleteValue(Value *PtrVal) {
+ // Notify the alias analysis implementation that this value is gone.
+ AA.deleteValue(PtrVal);
+
+ // First, look up the PointerRec for this pointer.
+ hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
+ if (I == PointerMap.end()) return; // Noop
+
+ // If we found one, remove the pointer from the alias set it is in.
+ AliasSet::HashNodePair &PtrValEnt = *I;
+ AliasSet *AS = PtrValEnt.second.getAliasSet(*this);
+
+ // Unlink from the list of values...
+ PtrValEnt.second.removeFromList();
+ // Stop using the alias set
+ AS->dropRef(*this);
+ PointerMap.erase(I);
+}
+
+// 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 AliasSetTracker::copyValue(Value *From, Value *To) {
+ // Notify the alias analysis implementation that this value is copied.
+ AA.copyValue(From, To);
+
+ // First, look up the PointerRec for this pointer.
+ hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(From);
+ if (I == PointerMap.end() || !I->second.hasAliasSet())
+ return; // Noop
+
+ AliasSet::HashNodePair &Entry = getEntryFor(To);
+ if (Entry.second.hasAliasSet()) return; // Already in the tracker!
+
+ // Add it to the alias set it aliases...
+ AliasSet *AS = I->second.getAliasSet(*this);
+ AS->addPointer(*this, Entry, I->second.getSize(), true);
+}
+
+
+
//===----------------------------------------------------------------------===//
// AliasSet/AliasSetTracker Printing Support
//===----------------------------------------------------------------------===//
case ModRef : OS << "Mod/Ref "; break;
default: assert(0 && "Bad value for AccessTy!");
}
+ if (isVolatile()) OS << "[volatile] ";
if (Forward)
OS << " forwarding to " << (void*)Forward;
OS << "Pointers: ";
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I != begin()) OS << ", ";
- WriteAsOperand(OS << "(", I->first);
- OS << ", " << I->second.getSize() << ")";
+ WriteAsOperand(OS << "(", I.getPointer());
+ OS << ", " << I.getSize() << ")";
}
}
if (!CallSites.empty()) {
for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
if (i) OS << ", ";
WriteAsOperand(OS, CallSites[i].getCalledValue());
- }
+ }
}
OS << "\n";
}
void AliasSet::dump() const { print (std::cerr); }
void AliasSetTracker::dump() const { print(std::cerr); }
-
//===----------------------------------------------------------------------===//
// AliasSetPrinter Pass
//===----------------------------------------------------------------------===//
Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>());
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
- Tracker->add(*I);
+ Tracker->add(&*I);
return false;
}
/// print - Convert to human readable form
- virtual void print(std::ostream &OS) const {
+ virtual void print(std::ostream &OS, const Module* = 0) const {
Tracker->print(OS);
}
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