//===- 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/iMemory.h"
#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"
+using namespace llvm;
-/// updateAccessTypes - Depending on what type of accesses are in this set,
-/// decide whether the set contains just references, just modifications, or a
-/// mix.
+/// mergeSetIn - Merge the specified alias set into this alias set...
///
-void AliasSet::updateAccessType() {
- if (!Calls.empty() || !Invokes.empty()) {
- AccessTy = ModRef;
- } else if (!Loads.empty()) {
- if (Stores.empty())
- AccessTy = Refs;
- else
- AccessTy = ModRef;
- } else {
- AccessTy = Mods;
+void AliasSet::mergeSetIn(AliasSet &AS) {
+ assert(!AS.Forward && "Alias set is already forwarding!");
+ assert(!Forward && "This set is a forwarding set!!");
+
+ // Update the alias and access types of this set...
+ AccessTy |= AS.AccessTy;
+ AliasTy |= AS.AliasTy;
+
+ if (CallSites.empty()) { // Merge call sites...
+ if (!AS.CallSites.empty())
+ std::swap(CallSites, AS.CallSites);
+ } else if (!AS.CallSites.empty()) {
+ 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...
+
+ // Merge the list of constituent pointers...
+ if (AS.PtrList) {
+ *PtrListEnd = AS.PtrList;
+ AS.PtrList->second.setPrevInList(PtrListEnd);
+ PtrListEnd = AS.PtrListEnd;
+
+ AS.PtrList = 0;
+ AS.PtrListEnd = &AS.PtrList;
}
}
-/// mergeSetIn - Merge the specified alias set into this alias set...
-///
-void AliasSet::mergeSetIn(const AliasSet &AS) {
- // Merge instruction sets...
- Loads.insert( Loads.end(), AS.Loads.begin() , AS.Loads.end());
- Stores.insert( Stores.end(), AS.Stores.begin() , AS.Stores.end());
- Calls.insert( Calls.end(), AS.Calls.begin() , AS.Calls.end());
- Invokes.insert(Invokes.end(), AS.Invokes.begin(), AS.Invokes.end());
+void AliasSetTracker::removeAliasSet(AliasSet *AS) {
+ AliasSets.erase(AS);
+}
- // Update the alias and access types of this set...
- if (AS.getAliasType() == MayAlias)
- AliasTy = MayAlias;
- updateAccessType();
+void AliasSet::removeFromTracker(AliasSetTracker &AST) {
+ assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
+ AST.removeAliasSet(this);
}
-/// pointerAliasesSet - Return true if the specified pointer "may" (or must)
+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 (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...
+ assert(*PtrListEnd == 0 && "End of list is not null?");
+ *PtrListEnd = &Entry;
+ PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
+ RefCount++; // Entry points to alias set...
+}
+
+void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
+ CallSites.push_back(CS);
+
+ if (Function *F = CS.getCalledFunction()) {
+ if (AA.doesNotAccessMemory(F))
+ return;
+ else if (AA.onlyReadsMemory(F)) {
+ 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)
/// alias one of the members in the set.
///
-bool AliasSet::pointerAliasesSet(const Value *Ptr, AliasAnalysis &AA) const {
- if (!Calls.empty() || !Invokes.empty())
- return true;
- for (unsigned i = 0, e = Loads.size(); i != e; ++i)
- if (AA.alias(Ptr, Loads[i]->getOperand(0)))
- return true;
- for (unsigned i = 0, e = Stores.size(); i != e; ++i)
- if (AA.alias(Ptr, Stores[i]->getOperand(1)))
+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...
+ HashNodePair *SomePtr = getSomePointer();
+ assert(SomePtr && "Empty must-alias set??");
+ 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, Size, I->first, I->second.getSize()))
return true;
+
+ // Check the call sites list and invoke list...
+ if (!CallSites.empty())
+ // FIXME: this is pessimistic!
+ return true;
+
return false;
}
-/// getSomePointer - This method may only be called when the AliasType of the
-/// set is MustAlias. This is used to return any old pointer (which must alias
-/// all other pointers in the set) so that the caller can decide whether to turn
-/// this set into a may alias set or not.
-///
-Value *AliasSet::getSomePointer() const {
- assert(getAliasType() == MustAlias &&
- "Cannot call getSomePointer on a 'MayAlias' set!");
- assert(Calls.empty() && Invokes.empty() && "Call/invokes mean may alias!");
+bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
+ // FIXME: Use mod/ref information to prune this better!
+ if (Function *F = CS.getCalledFunction())
+ if (AA.doesNotAccessMemory(F))
+ return false;
- if (!Loads.empty())
- return Loads[0]->getOperand(0);
- assert(!Stores.empty() && "There are no instructions in this set!");
- return Stores[0]->getOperand(1);
+ return true;
}
-
/// findAliasSetForPointer - Given a pointer, find the one alias set to put the
/// 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 (unsigned i = 0; i != AliasSets.size(); ++i) {
- if (AliasSets[i].pointerAliasesSet(Ptr, AA)) {
+ 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...
- FoundSet = &AliasSets[i]; // Remember it.
+ FoundSet = I; // Remember it.
} else { // Otherwise, we must merge the sets...
- FoundSet->mergeSetIn(AliasSets[i]); // Merge in contents...
- AliasSets.erase(AliasSets.begin()+i); // Remove the set...
- --i; // Don't skip the next set
+ FoundSet->mergeSetIn(*I); // Merge in contents...
+ }
+ }
+
+ return FoundSet;
+}
+
+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...
+ FoundSet = I; // Remember it.
+ } else if (!I->Forward) { // Otherwise, we must merge the sets...
+ FoundSet->mergeSetIn(*I); // Merge in contents...
}
}
- }
return FoundSet;
}
-void AliasSetTracker::add(LoadInst *LI) {
- Value *Pointer = LI->getOperand(0);
-
- // Check to see if the loaded pointer aliases any sets...
- AliasSet *AS = findAliasSetForPointer(Pointer);
- if (AS) {
- AS->Loads.push_back(LI);
- // Check to see if we need to change this into a MayAlias set now...
- if (AS->getAliasType() == AliasSet::MustAlias)
- if (AA.alias(AS->getSomePointer(), Pointer) != AliasAnalysis::MustAlias)
- AS->AliasTy = AliasSet::MayAlias;
- AS->updateAccessType();
+
+
+/// getAliasSetForPointer - Return the alias set that the specified pointer
+/// lives in...
+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() && Size <= Entry.second.getSize()) {
+ // Return the set!
+ return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
+ } else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
+ // Add it to the alias set it aliases...
+ AS->addPointer(*this, Entry, Size);
+ return *AS;
} else {
- // Otherwise create a new alias set to hold the load...
+ // Otherwise create a new alias set to hold the loaded pointer...
AliasSets.push_back(AliasSet());
- AliasSets.back().Loads.push_back(LI);
- AliasSets.back().AccessTy = AliasSet::Refs;
+ AliasSets.back().addPointer(*this, Entry, Size);
+ return AliasSets.back();
}
}
+void AliasSetTracker::add(LoadInst *LI) {
+ AliasSet &AS =
+ addPointer(LI->getOperand(0),
+ AA.getTargetData().getTypeSize(LI->getType()), AliasSet::Refs);
+ if (LI->isVolatile()) AS.setVolatile();
+}
+
void AliasSetTracker::add(StoreInst *SI) {
- Value *Pointer = SI->getOperand(1);
-
- // Check to see if the loaded pointer aliases any sets...
- AliasSet *AS = findAliasSetForPointer(Pointer);
- if (AS) {
- AS->Stores.push_back(SI);
- // Check to see if we need to change this into a MayAlias set now...
- if (AS->getAliasType() == AliasSet::MustAlias)
- if (AA.alias(AS->getSomePointer(), Pointer) != AliasAnalysis::MustAlias)
- AS->AliasTy = AliasSet::MayAlias;
- AS->updateAccessType();
- } else {
- // Otherwise create a new alias set to hold the load...
+ AliasSet &AS =
+ addPointer(SI->getOperand(1),
+ AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()),
+ AliasSet::Mods);
+ if (SI->isVolatile()) AS.setVolatile();
+}
+
+
+void AliasSetTracker::add(CallSite CS) {
+ if (Function *F = CS.getCalledFunction())
+ if (AA.doesNotAccessMemory(F))
+ return;
+
+ AliasSet *AS = findAliasSetForCallSite(CS);
+ if (!AS) {
AliasSets.push_back(AliasSet());
- AliasSets.back().Stores.push_back(SI);
- AliasSets.back().AccessTy = AliasSet::Mods;
+ AS = &AliasSets.back();
}
+ AS->addCallSite(CS, AA);
}
+void AliasSetTracker::add(Instruction *I) {
+ // Dispatch to one of the other add methods...
+ if (LoadInst *LI = dyn_cast<LoadInst>(I))
+ add(LI);
+ else if (StoreInst *SI = dyn_cast<StoreInst>(I))
+ add(SI);
+ else if (CallInst *CI = dyn_cast<CallInst>(I))
+ add(CI);
+ else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
+ add(II);
+}
+
+void AliasSetTracker::add(BasicBlock &BB) {
+ for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
+ add(I);
+}
-void AliasSetTracker::mergeAllSets() {
- if (AliasSets.size() < 2) return; // Noop
+void AliasSetTracker::add(const AliasSetTracker &AST) {
+ assert(&AA == &AST.AA &&
+ "Merging AliasSetTracker objects with different Alias Analyses!");
- // Merge all of the sets into set #0
- for (unsigned i = 1, e = AliasSets.size(); i != e; ++i)
- AliasSets[0].mergeSetIn(AliasSets[i]);
+ // 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);
- // Delete extraneous sets...
- AliasSets.erase(AliasSets.begin()+1, AliasSets.end());
+ // 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();
+ for (; I != E; ++I)
+ addPointer(I->first, I->second.getSize(),
+ (AliasSet::AccessType)AS.AccessTy);
+ }
}
-void AliasSetTracker::add(CallInst *CI) {
- if (!AliasSets.empty()) {
- mergeAllSets();
- } else {
- AliasSets.push_back(AliasSet());
- }
- AliasSets[0].AccessTy = AliasSet::ModRef;
- AliasSets[0].AliasTy = AliasSet::MayAlias;
- AliasSets[0].Calls.push_back(CI);
+
+// remove 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::remove(Value *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
+ if (--AS->RefCount == 0)
+ AS->removeFromTracker(*this);
+
+ PointerMap.erase(I);
}
-void AliasSetTracker::add(InvokeInst *II) {
- if (!AliasSets.empty()) {
- mergeAllSets();
- } else {
- AliasSets.push_back(AliasSet());
+
+//===----------------------------------------------------------------------===//
+// AliasSet/AliasSetTracker Printing Support
+//===----------------------------------------------------------------------===//
+
+void AliasSet::print(std::ostream &OS) const {
+ OS << " AliasSet[" << (void*)this << "," << RefCount << "] ";
+ OS << (AliasTy == MustAlias ? "must" : "may ") << " alias, ";
+ switch (AccessTy) {
+ case NoModRef: OS << "No access "; break;
+ case Refs : OS << "Ref "; break;
+ case Mods : OS << "Mod "; break;
+ case ModRef : OS << "Mod/Ref "; break;
+ default: assert(0 && "Bad value for AccessTy!");
}
- AliasSets[0].AccessTy = AliasSet::ModRef;
- AliasSets[0].AliasTy = AliasSet::MayAlias;
- AliasSets[0].Invokes.push_back(II);
+ if (isVolatile()) OS << "[volatile] ";
+ if (Forward)
+ OS << " forwarding to " << (void*)Forward;
+
+
+ if (begin() != end()) {
+ OS << "Pointers: ";
+ for (iterator I = begin(), E = end(); I != E; ++I) {
+ if (I != begin()) OS << ", ";
+ WriteAsOperand(OS << "(", I->first);
+ OS << ", " << I->second.getSize() << ")";
+ }
+ }
+ if (!CallSites.empty()) {
+ OS << "\n " << CallSites.size() << " Call Sites: ";
+ for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
+ if (i) OS << ", ";
+ WriteAsOperand(OS, CallSites[i].getCalledValue());
+ }
+ }
+ OS << "\n";
+}
+
+void AliasSetTracker::print(std::ostream &OS) const {
+ OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for "
+ << PointerMap.size() << " pointer values.\n";
+ for (const_iterator I = begin(), E = end(); I != E; ++I)
+ I->print(OS);
+ OS << "\n";
+}
+
+void AliasSet::dump() const { print (std::cerr); }
+void AliasSetTracker::dump() const { print(std::cerr); }
+
+//===----------------------------------------------------------------------===//
+// AliasSetPrinter Pass
+//===----------------------------------------------------------------------===//
+
+namespace {
+ class AliasSetPrinter : public FunctionPass {
+ AliasSetTracker *Tracker;
+ public:
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<AliasAnalysis>();
+ }
+
+ virtual bool runOnFunction(Function &F) {
+ Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>());
+
+ for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
+ Tracker->add(*I);
+ return false;
+ }
+
+ /// print - Convert to human readable form
+ virtual void print(std::ostream &OS) const {
+ Tracker->print(OS);
+ }
+
+ virtual void releaseMemory() {
+ delete Tracker;
+ }
+ };
+ RegisterPass<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer",
+ PassInfo::Analysis | PassInfo::Optimization);
}