llvm-6502/lib/Analysis/AliasSetTracker.cpp
Dan Gohman 844731a7f1 Clean up the use of static and anonymous namespaces. This turned up
several things that were neither in an anonymous namespace nor static
but not intended to be global.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51017 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-13 00:00:25 +00:00

593 lines
19 KiB
C++

//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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/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.
///
void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
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 (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);
} else if (!AS.CallSites.empty()) {
CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
AS.CallSites.clear();
}
AS.Forward = this; // Forward across AS now...
addRef(); // 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;
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::removeFromTracker(AliasSetTracker &AST) {
assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
AST.removeAliasSet(this);
}
void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
unsigned Size, bool KnownMustAlias) {
assert(!Entry.second.hasAliasSet() && "Entry already in set!");
// 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)
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);
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);
AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(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)
/// alias one of the members in the set.
///
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.getPointer(), I.getSize()))
return true;
// Check the call sites list and invoke list...
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 {
if (AA.doesNotAccessMemory(CS))
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;
}
/// 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,
unsigned Size) {
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.
FoundSet = I; // Remember it.
} 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.
FoundSet = I; // Remember it.
} else if (!I->Forward) { // Otherwise, we must merge the sets.
FoundSet->mergeSetIn(*I, *this); // Merge in contents.
}
}
return FoundSet;
}
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in...
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()) {
Entry.second.updateSize(Size);
// 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 {
if (New) *New = true;
// Otherwise create a new alias set to hold the loaded pointer...
AliasSets.push_back(new AliasSet());
AliasSets.back().addPointer(*this, Entry, Size);
return AliasSets.back();
}
}
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().getTypeStoreSize(LI->getType()),
AliasSet::Refs, NewPtr);
if (LI->isVolatile()) AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(StoreInst *SI) {
bool NewPtr;
Value *Val = SI->getOperand(0);
AliasSet &AS = addPointer(SI->getOperand(1),
AA.getTargetData().getTypeStoreSize(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);
// Free operations are volatile ops (cannot be moved).
AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(VAArgInst *VAAI) {
bool NewPtr;
addPointer(VAAI->getOperand(0), ~0, AliasSet::ModRef, NewPtr);
return NewPtr;
}
bool AliasSetTracker::add(CallSite CS) {
if (AA.doesNotAccessMemory(CS))
return true; // doesn't alias anything
AliasSet *AS = findAliasSetForCallSite(CS);
if (!AS) {
AliasSets.push_back(new AliasSet());
AS = &AliasSets.back();
AS->addCallSite(CS, AA);
return true;
} else {
AS->addCallSite(CS, AA);
return false;
}
}
bool AliasSetTracker::add(Instruction *I) {
// Dispatch to one of the other add methods...
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return add(LI);
else if (StoreInst *SI = dyn_cast<StoreInst>(I))
return add(SI);
else if (CallInst *CI = dyn_cast<CallInst>(I))
return add(CI);
else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
return add(II);
else if (FreeInst *FI = dyn_cast<FreeInst>(I))
return add(FI);
else if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return add(VAAI);
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) {
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().getTypeStoreSize(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().getTypeStoreSize(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(VAArgInst *VAAI) {
AliasSet *AS = findAliasSetForPointer(VAAI->getOperand(0), ~0);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(CallSite CS) {
if (AA.doesNotAccessMemory(CS))
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);
else if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return remove(VAAI);
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);
// If this is a call instruction, remove the callsite from the appropriate
// AliasSet.
CallSite CS = CallSite::get(PtrVal);
if (CS.getInstruction())
if (!AA.doesNotAccessMemory(CS))
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
// 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
//===----------------------------------------------------------------------===//
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!");
}
if (isVolatile()) OS << "[volatile] ";
if (Forward)
OS << " forwarding to " << (void*)Forward;
if (!empty()) {
OS << "Pointers: ";
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I != begin()) OS << ", ";
WriteAsOperand(OS << "(", I.getPointer());
OS << ", " << I.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 (cerr); }
void AliasSetTracker::dump() const { print(cerr); }
//===----------------------------------------------------------------------===//
// AliasSetPrinter Pass
//===----------------------------------------------------------------------===//
namespace {
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>();
}
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);
Tracker->print(cerr);
delete Tracker;
return false;
}
};
}
char AliasSetPrinter::ID = 0;
static RegisterPass<AliasSetPrinter>
X("print-alias-sets", "Alias Set Printer", false, true);