1 //===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the AliasSetTracker and AliasSet classes.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/AliasSetTracker.h"
15 #include "llvm/Analysis/AliasAnalysis.h"
16 #include "llvm/iMemory.h"
17 #include "llvm/iOther.h"
18 #include "llvm/iTerminators.h"
19 #include "llvm/Pass.h"
20 #include "llvm/Target/TargetData.h"
21 #include "llvm/Assembly/Writer.h"
22 #include "llvm/Support/InstIterator.h"
25 /// mergeSetIn - Merge the specified alias set into this alias set...
27 void AliasSet::mergeSetIn(AliasSet &AS) {
28 assert(!AS.Forward && "Alias set is already forwarding!");
29 assert(!Forward && "This set is a forwarding set!!");
31 // Update the alias and access types of this set...
32 AccessTy |= AS.AccessTy;
33 AliasTy |= AS.AliasTy;
35 if (CallSites.empty()) { // Merge call sites...
36 if (!AS.CallSites.empty())
37 std::swap(CallSites, AS.CallSites);
38 } else if (!AS.CallSites.empty()) {
39 CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
43 // FIXME: If AS's refcount is zero, nuke it now...
44 assert(RefCount != 0);
46 AS.Forward = this; // Forward across AS now...
47 RefCount++; // AS is now pointing to us...
49 // Merge the list of constituent pointers...
50 PtrListTail->second.setTail(AS.PtrListHead);
51 PtrListTail = AS.PtrListTail;
52 AS.PtrListHead = AS.PtrListTail = 0;
55 void AliasSetTracker::removeAliasSet(AliasSet *AS) {
59 void AliasSet::removeFromTracker(AliasSetTracker &AST) {
60 assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
61 AST.removeAliasSet(this);
64 void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
66 assert(!Entry.second.hasAliasSet() && "Entry already in set!");
68 AliasAnalysis &AA = AST.getAliasAnalysis();
70 if (isMustAlias()) // Check to see if we have to downgrade to _may_ alias
71 if (HashNodePair *P = getSomePointer()) {
72 AliasAnalysis::AliasResult Result =
73 AA.alias(P->first, P->second.getSize(), Entry.first, Size);
74 if (Result == AliasAnalysis::MayAlias)
76 else // First entry of must alias must have maximum size!
77 P->second.updateSize(Size);
78 assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
81 Entry.second.setAliasSet(this);
82 Entry.second.updateSize(Size);
84 // Add it to the end of the list...
86 PtrListTail->second.setTail(&Entry);
90 RefCount++; // Entry points to alias set...
93 void AliasSet::addCallSite(CallSite CS) {
94 CallSites.push_back(CS);
95 AliasTy = MayAlias; // FIXME: Too conservative?
99 /// aliasesPointer - Return true if the specified pointer "may" (or must)
100 /// alias one of the members in the set.
102 bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
103 AliasAnalysis &AA) const {
104 if (AliasTy == MustAlias) {
105 assert(CallSites.empty() && "Illegal must alias set!");
107 // If this is a set of MustAliases, only check to see if the pointer aliases
108 // SOME value in the set...
109 HashNodePair *SomePtr = getSomePointer();
110 assert(SomePtr && "Empty must-alias set??");
111 return AA.alias(SomePtr->first, SomePtr->second.getSize(), Ptr, Size);
114 // If this is a may-alias set, we have to check all of the pointers in the set
115 // to be sure it doesn't alias the set...
116 for (iterator I = begin(), E = end(); I != E; ++I)
117 if (AA.alias(Ptr, Size, I->first, I->second.getSize()))
120 // Check the call sites list and invoke list...
121 if (!CallSites.empty())
122 // FIXME: this is pessimistic!
128 bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
129 // FIXME: Too conservative!
134 /// findAliasSetForPointer - Given a pointer, find the one alias set to put the
135 /// instruction referring to the pointer into. If there are multiple alias sets
136 /// that may alias the pointer, merge them together and return the unified set.
138 AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
140 AliasSet *FoundSet = 0;
141 for (iterator I = begin(), E = end(); I != E; ++I)
142 if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
143 if (FoundSet == 0) { // If this is the first alias set ptr can go into...
144 FoundSet = I; // Remember it.
145 } else { // Otherwise, we must merge the sets...
146 FoundSet->mergeSetIn(*I); // Merge in contents...
153 AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
154 AliasSet *FoundSet = 0;
155 for (iterator I = begin(), E = end(); I != E; ++I)
156 if (!I->Forward && I->aliasesCallSite(CS, AA)) {
157 if (FoundSet == 0) { // If this is the first alias set ptr can go into...
158 FoundSet = I; // Remember it.
159 } else if (!I->Forward) { // Otherwise, we must merge the sets...
160 FoundSet->mergeSetIn(*I); // Merge in contents...
170 /// getAliasSetForPointer - Return the alias set that the specified pointer
172 AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size){
173 AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
175 // Check to see if the pointer is already known...
176 if (Entry.second.hasAliasSet() && Size <= Entry.second.getSize()) {
178 return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
179 } else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
180 // Add it to the alias set it aliases...
181 AS->addPointer(*this, Entry, Size);
184 // Otherwise create a new alias set to hold the loaded pointer...
185 AliasSets.push_back(AliasSet());
186 AliasSets.back().addPointer(*this, Entry, Size);
187 return AliasSets.back();
191 void AliasSetTracker::add(LoadInst *LI) {
193 addPointer(LI->getOperand(0),
194 AA.getTargetData().getTypeSize(LI->getType()), AliasSet::Refs);
195 if (LI->isVolatile()) AS.setVolatile();
198 void AliasSetTracker::add(StoreInst *SI) {
200 addPointer(SI->getOperand(1),
201 AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()),
203 if (SI->isVolatile()) AS.setVolatile();
207 void AliasSetTracker::add(CallSite CS) {
208 AliasSet *AS = findAliasSetForCallSite(CS);
210 AliasSets.push_back(AliasSet());
211 AS = &AliasSets.back();
216 void AliasSetTracker::add(Instruction *I) {
217 // Dispatch to one of the other add methods...
218 if (LoadInst *LI = dyn_cast<LoadInst>(I))
220 else if (StoreInst *SI = dyn_cast<StoreInst>(I))
222 else if (CallInst *CI = dyn_cast<CallInst>(I))
224 else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
228 void AliasSetTracker::add(BasicBlock &BB) {
229 for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
233 void AliasSetTracker::add(const AliasSetTracker &AST) {
234 assert(&AA == &AST.AA &&
235 "Merging AliasSetTracker objects with different Alias Analyses!");
237 // Loop over all of the alias sets in AST, adding the pointers contained
238 // therein into the current alias sets. This can cause alias sets to be
239 // merged together in the current AST.
240 for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I)
241 if (!I->Forward) { // Ignore forwarding alias sets
242 AliasSet &AS = const_cast<AliasSet&>(*I);
244 // If there are any call sites in the alias set, add them to this AST.
245 for (unsigned i = 0, e = AS.CallSites.size(); i != e; ++i)
246 add(AS.CallSites[i]);
248 // Loop over all of the pointers in this alias set...
249 AliasSet::iterator I = AS.begin(), E = AS.end();
251 addPointer(I->first, I->second.getSize(),
252 (AliasSet::AccessType)AS.AccessTy);
256 //===----------------------------------------------------------------------===//
257 // AliasSet/AliasSetTracker Printing Support
258 //===----------------------------------------------------------------------===//
260 void AliasSet::print(std::ostream &OS) const {
261 OS << " AliasSet[" << (void*)this << "," << RefCount << "] ";
262 OS << (AliasTy == MustAlias ? "must" : "may ") << " alias, ";
264 case NoModRef: OS << "No access "; break;
265 case Refs : OS << "Ref "; break;
266 case Mods : OS << "Mod "; break;
267 case ModRef : OS << "Mod/Ref "; break;
268 default: assert(0 && "Bad value for AccessTy!");
270 if (isVolatile()) OS << "[volatile] ";
272 OS << " forwarding to " << (void*)Forward;
275 if (begin() != end()) {
277 for (iterator I = begin(), E = end(); I != E; ++I) {
278 if (I != begin()) OS << ", ";
279 WriteAsOperand(OS << "(", I->first);
280 OS << ", " << I->second.getSize() << ")";
283 if (!CallSites.empty()) {
284 OS << "\n " << CallSites.size() << " Call Sites: ";
285 for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
287 WriteAsOperand(OS, CallSites[i].getCalledValue());
293 void AliasSetTracker::print(std::ostream &OS) const {
294 OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for "
295 << PointerMap.size() << " pointer values.\n";
296 for (const_iterator I = begin(), E = end(); I != E; ++I)
301 void AliasSet::dump() const { print (std::cerr); }
302 void AliasSetTracker::dump() const { print(std::cerr); }
304 //===----------------------------------------------------------------------===//
305 // AliasSetPrinter Pass
306 //===----------------------------------------------------------------------===//
309 class AliasSetPrinter : public FunctionPass {
310 AliasSetTracker *Tracker;
312 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
313 AU.setPreservesAll();
314 AU.addRequired<AliasAnalysis>();
317 virtual bool runOnFunction(Function &F) {
318 Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>());
320 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
325 /// print - Convert to human readable form
326 virtual void print(std::ostream &OS) const {
330 virtual void releaseMemory() {
334 RegisterPass<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer",
335 PassInfo::Analysis | PassInfo::Optimization);