1 //===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
3 // This file implements the AliasSetTracker and AliasSet classes.
5 //===----------------------------------------------------------------------===//
7 #include "llvm/Analysis/AliasSetTracker.h"
8 #include "llvm/Analysis/AliasAnalysis.h"
9 #include "llvm/iMemory.h"
10 #include "llvm/iOther.h"
11 #include "llvm/iTerminators.h"
12 #include "llvm/Pass.h"
13 #include "llvm/Target/TargetData.h"
14 #include "llvm/Assembly/Writer.h"
15 #include "llvm/Support/InstIterator.h"
17 /// mergeSetIn - Merge the specified alias set into this alias set...
19 void AliasSet::mergeSetIn(AliasSet &AS) {
20 assert(!AS.Forward && "Alias set is already forwarding!");
21 assert(!Forward && "This set is a forwarding set!!");
23 // Update the alias and access types of this set...
24 AccessTy |= AS.AccessTy;
25 AliasTy |= AS.AliasTy;
27 if (CallSites.empty()) { // Merge call sites...
28 if (!AS.CallSites.empty())
29 std::swap(CallSites, AS.CallSites);
30 } else if (!AS.CallSites.empty()) {
31 CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
35 // FIXME: If AS's refcount is zero, nuke it now...
36 assert(RefCount != 0);
38 AS.Forward = this; // Forward across AS now...
39 RefCount++; // AS is now pointing to us...
41 // Merge the list of constituent pointers...
42 PtrListTail->second.setTail(AS.PtrListHead);
43 PtrListTail = AS.PtrListTail;
44 AS.PtrListHead = AS.PtrListTail = 0;
47 void AliasSetTracker::removeAliasSet(AliasSet *AS) {
51 void AliasSet::removeFromTracker(AliasSetTracker &AST) {
52 assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
53 AST.removeAliasSet(this);
56 void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
58 assert(!Entry.second.hasAliasSet() && "Entry already in set!");
60 AliasAnalysis &AA = AST.getAliasAnalysis();
62 if (isMustAlias()) // Check to see if we have to downgrade to _may_ alias
63 if (HashNodePair *P = getSomePointer()) {
64 AliasAnalysis::AliasResult Result =
65 AA.alias(P->first, P->second.getSize(), Entry.first, Size);
66 if (Result == AliasAnalysis::MayAlias)
68 else // First entry of must alias must have maximum size!
69 P->second.updateSize(Size);
70 assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
73 Entry.second.setAliasSet(this);
74 Entry.second.updateSize(Size);
76 // Add it to the end of the list...
78 PtrListTail->second.setTail(&Entry);
82 RefCount++; // Entry points to alias set...
85 void AliasSet::addCallSite(CallSite CS) {
86 CallSites.push_back(CS);
87 AliasTy = MayAlias; // FIXME: Too conservative?
91 /// aliasesPointer - Return true if the specified pointer "may" (or must)
92 /// alias one of the members in the set.
94 bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
95 AliasAnalysis &AA) const {
96 if (AliasTy == MustAlias) {
97 assert(CallSites.empty() && "Illegal must alias set!");
99 // If this is a set of MustAliases, only check to see if the pointer aliases
100 // SOME value in the set...
101 HashNodePair *SomePtr = getSomePointer();
102 assert(SomePtr && "Empty must-alias set??");
103 return AA.alias(SomePtr->first, SomePtr->second.getSize(), Ptr, Size);
106 // If this is a may-alias set, we have to check all of the pointers in the set
107 // to be sure it doesn't alias the set...
108 for (iterator I = begin(), E = end(); I != E; ++I)
109 if (AA.alias(Ptr, Size, I->first, I->second.getSize()))
112 // Check the call sites list and invoke list...
113 if (!CallSites.empty())
114 // FIXME: this is pessimistic!
120 bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
121 // FIXME: Too conservative!
126 /// findAliasSetForPointer - Given a pointer, find the one alias set to put the
127 /// instruction referring to the pointer into. If there are multiple alias sets
128 /// that may alias the pointer, merge them together and return the unified set.
130 AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
132 AliasSet *FoundSet = 0;
133 for (iterator I = begin(), E = end(); I != E; ++I)
134 if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
135 if (FoundSet == 0) { // If this is the first alias set ptr can go into...
136 FoundSet = I; // Remember it.
137 } else { // Otherwise, we must merge the sets...
138 FoundSet->mergeSetIn(*I); // Merge in contents...
145 AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
146 AliasSet *FoundSet = 0;
147 for (iterator I = begin(), E = end(); I != E; ++I)
148 if (!I->Forward && I->aliasesCallSite(CS, AA)) {
149 if (FoundSet == 0) { // If this is the first alias set ptr can go into...
150 FoundSet = I; // Remember it.
151 } else if (!I->Forward) { // Otherwise, we must merge the sets...
152 FoundSet->mergeSetIn(*I); // Merge in contents...
162 /// getAliasSetForPointer - Return the alias set that the specified pointer
164 AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size){
165 AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
167 // Check to see if the pointer is already known...
168 if (Entry.second.hasAliasSet() && Size <= Entry.second.getSize()) {
170 return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
171 } else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
172 // Add it to the alias set it aliases...
173 AS->addPointer(*this, Entry, Size);
176 // Otherwise create a new alias set to hold the loaded pointer...
177 AliasSets.push_back(AliasSet());
178 AliasSets.back().addPointer(*this, Entry, Size);
179 return AliasSets.back();
183 void AliasSetTracker::add(LoadInst *LI) {
184 addPointer(LI->getOperand(0),
185 AA.getTargetData().getTypeSize(LI->getType()), AliasSet::Refs);
188 void AliasSetTracker::add(StoreInst *SI) {
189 addPointer(SI->getOperand(1),
190 AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()),
194 void AliasSetTracker::add(CallSite CS) {
195 AliasSet *AS = findAliasSetForCallSite(CS);
197 AliasSets.push_back(AliasSet());
198 AS = &AliasSets.back();
203 void AliasSetTracker::add(Instruction *I) {
204 // Dispatch to one of the other add methods...
205 if (LoadInst *LI = dyn_cast<LoadInst>(I))
207 else if (StoreInst *SI = dyn_cast<StoreInst>(I))
209 else if (CallInst *CI = dyn_cast<CallInst>(I))
211 else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
215 void AliasSetTracker::add(BasicBlock &BB) {
216 for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
220 void AliasSetTracker::add(const AliasSetTracker &AST) {
221 assert(&AA == &AST.AA &&
222 "Merging AliasSetTracker objects with different Alias Analyses!");
224 // Loop over all of the alias sets in AST, adding the pointers contained
225 // therein into the current alias sets. This can cause alias sets to be
226 // merged together in the current AST.
227 for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I)
228 if (!I->Forward) { // Ignore forwarding alias sets
229 AliasSet &AS = const_cast<AliasSet&>(*I);
231 // If there are any call sites in the alias set, add them to this AST.
232 for (unsigned i = 0, e = AS.CallSites.size(); i != e; ++i)
233 add(AS.CallSites[i]);
235 // Loop over all of the pointers in this alias set...
236 AliasSet::iterator I = AS.begin(), E = AS.end();
238 addPointer(I->first, I->second.getSize(),
239 (AliasSet::AccessType)AS.AccessTy);
243 //===----------------------------------------------------------------------===//
244 // AliasSet/AliasSetTracker Printing Support
245 //===----------------------------------------------------------------------===//
247 void AliasSet::print(std::ostream &OS) const {
248 OS << " AliasSet[" << (void*)this << "," << RefCount << "] ";
249 OS << (AliasTy == MustAlias ? "must" : "may ") << " alias, ";
251 case NoModRef: OS << "No access "; break;
252 case Refs : OS << "Ref "; break;
253 case Mods : OS << "Mod "; break;
254 case ModRef : OS << "Mod/Ref "; break;
255 default: assert(0 && "Bad value for AccessTy!");
258 OS << " forwarding to " << (void*)Forward;
261 if (begin() != end()) {
263 for (iterator I = begin(), E = end(); I != E; ++I) {
264 if (I != begin()) OS << ", ";
265 WriteAsOperand(OS << "(", I->first);
266 OS << ", " << I->second.getSize() << ")";
269 if (!CallSites.empty()) {
270 OS << "\n " << CallSites.size() << " Call Sites: ";
271 for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
273 WriteAsOperand(OS, CallSites[i].getCalledValue());
279 void AliasSetTracker::print(std::ostream &OS) const {
280 OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for "
281 << PointerMap.size() << " pointer values.\n";
282 for (const_iterator I = begin(), E = end(); I != E; ++I)
287 void AliasSet::dump() const { print (std::cerr); }
288 void AliasSetTracker::dump() const { print(std::cerr); }
291 //===----------------------------------------------------------------------===//
292 // AliasSetPrinter Pass
293 //===----------------------------------------------------------------------===//
296 class AliasSetPrinter : public FunctionPass {
297 AliasSetTracker *Tracker;
299 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
300 AU.setPreservesAll();
301 AU.addRequired<AliasAnalysis>();
304 virtual bool runOnFunction(Function &F) {
305 Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>());
307 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
312 /// print - Convert to human readable form
313 virtual void print(std::ostream &OS) const {
317 virtual void releaseMemory() {
321 RegisterPass<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer",
322 PassInfo::Analysis | PassInfo::Optimization);