//===- 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/Compiler.h"
#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/Streams.h"
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...
if (AS.PtrList) {
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)
assert(*PtrListEnd == 0 && "End of list is not null?");
*PtrListEnd = &Entry;
PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
- RefCount++; // Entry points to alias set...
+ assert(*PtrListEnd == 0 && "End of list is not null?");
+ addRef(); // 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))
+ AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS);
+ if (Behavior == AliasAnalysis::DoesNotAccessMemory)
return;
- else if (AA.onlyReadsMemory(F)) {
+ else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
AliasTy = MayAlias;
- AccessTy = Refs;
+ AccessTy |= Refs;
return;
}
}
// 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: Use mod/ref information to prune this better!
if (Function *F = CS.getCalledFunction())
if (AA.doesNotAccessMemory(F))
return false;
- return true;
+ 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) {
- AliasSet &AS =
- 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) {
- AliasSet &AS =
- 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;
}
+bool AliasSetTracker::add(FreeInst *FI) {
+ bool NewPtr;
+ AliasSet &AS = addPointer(FI->getOperand(0), ~0,
+ AliasSet::Mods, NewPtr);
-void AliasSetTracker::add(CallSite CS) {
+ // 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;
+ 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, AA);
}
-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) {
// 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);
+ bool X;
+ for (; I != E; ++I) {
+ AliasSet &NewAS = addPointer(I.getPointer(), I.getSize(),
+ (AliasSet::AccessType)AS.AccessTy, X);
+ if (AS.isVolatile()) NewAS.setVolatile();
+ }
}
}
+/// remove - Remove the specified (potentially non-empty) alias set from the
+/// tracker.
+void AliasSetTracker::remove(AliasSet &AS) {
+ // Drop all call sites.
+ AS.CallSites.clear();
+
+ // Clear the alias set.
+ unsigned NumRefs = 0;
+ while (!AS.empty()) {
+ AliasSet::HashNodePair *P = AS.PtrList;
+
+ // Unlink from the list of values.
+ P->second.removeFromList();
+
+ // Remember how many references need to be dropped.
+ ++NumRefs;
+
+ // Finally, remove the entry.
+ Value *Remove = P->first; // Take a copy because it is invalid to pass
+ PointerMap.erase(Remove); // a reference to the data being erased.
+ }
+
+ // Stop using the alias set, removing it.
+ AS.RefCount -= NumRefs;
+ if (AS.RefCount == 0)
+ AS.removeFromTracker(*this);
+}
+
+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;
+}
-// remove method - This method is used to remove a pointer value from the
+
+// 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::remove(Value *PtrVal) {
- // First, look up the PointerRec for this pointer...
+void AliasSetTracker::deleteValue(Value *PtrVal) {
+ // Notify the alias analysis implementation that this value is gone.
+ AA.deleteValue(PtrVal);
+
+ // If this is a call instruction, remove the callsite from the appropriate
+ // AliasSet.
+ CallSite CS = CallSite::get(PtrVal);
+ if (CS.getInstruction()) {
+ Function *F = CS.getCalledFunction();
+ if (!F || !AA.doesNotAccessMemory(F)) {
+ if (AliasSet *AS = findAliasSetForCallSite(CS))
+ AS->removeCallSite(CS);
+ }
+ }
+
+ // First, look up the PointerRec for this pointer.
hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
if (I == PointerMap.end()) return; // Noop
// Unlink from the list of values...
PtrValEnt.second.removeFromList();
// Stop using the alias set
- if (--AS->RefCount == 0)
- AS->removeFromTracker(*this);
-
+ 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
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";
}
OS << "\n";
}
-void AliasSet::dump() const { print (std::cerr); }
-void AliasSetTracker::dump() const { print(std::cerr); }
+void AliasSet::dump() const { print (cerr); }
+void AliasSetTracker::dump() const { print(cerr); }
//===----------------------------------------------------------------------===//
// AliasSetPrinter Pass
//===----------------------------------------------------------------------===//
namespace {
- class AliasSetPrinter : public FunctionPass {
+ class VISIBILITY_HIDDEN AliasSetPrinter : public FunctionPass {
AliasSetTracker *Tracker;
public:
+ static char ID; // Pass identification, replacement for typeid
+ AliasSetPrinter() : FunctionPass((intptr_t)&ID) {}
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<AliasAnalysis>();
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() {
+ Tracker->add(&*I);
+ Tracker->print(cerr);
delete Tracker;
+ return false;
}
};
- RegisterPass<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer",
- PassInfo::Analysis | PassInfo::Optimization);
+ char AliasSetPrinter::ID = 0;
+ RegisterPass<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer");
}
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