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the default aa impl results. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25062 91177308-0d34-0410-b5e6-96231b3b80d8
550 lines
18 KiB
C++
550 lines
18 KiB
C++
//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the AliasSetTracker and AliasSet classes.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/AliasSetTracker.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Instructions.h"
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#include "llvm/Pass.h"
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#include "llvm/Type.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Support/InstIterator.h"
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#include <iostream>
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using namespace llvm;
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/// mergeSetIn - Merge the specified alias set into this alias set.
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///
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void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
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assert(!AS.Forward && "Alias set is already forwarding!");
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assert(!Forward && "This set is a forwarding set!!");
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// Update the alias and access types of this set...
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AccessTy |= AS.AccessTy;
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AliasTy |= AS.AliasTy;
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if (AliasTy == MustAlias) {
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// Check that these two merged sets really are must aliases. Since both
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// used to be must-alias sets, we can just check any pointer from each set
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// for aliasing.
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AliasAnalysis &AA = AST.getAliasAnalysis();
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HashNodePair *L = getSomePointer();
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HashNodePair *R = AS.getSomePointer();
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// If the pointers are not a must-alias pair, this set becomes a may alias.
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if (AA.alias(L->first, L->second.getSize(), R->first, R->second.getSize())
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!= AliasAnalysis::MustAlias)
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AliasTy = MayAlias;
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}
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if (CallSites.empty()) { // Merge call sites...
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if (!AS.CallSites.empty())
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std::swap(CallSites, AS.CallSites);
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} else if (!AS.CallSites.empty()) {
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CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
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AS.CallSites.clear();
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}
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AS.Forward = this; // Forward across AS now...
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addRef(); // AS is now pointing to us...
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// Merge the list of constituent pointers...
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if (AS.PtrList) {
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*PtrListEnd = AS.PtrList;
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AS.PtrList->second.setPrevInList(PtrListEnd);
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PtrListEnd = AS.PtrListEnd;
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AS.PtrList = 0;
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AS.PtrListEnd = &AS.PtrList;
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assert(*AS.PtrListEnd == 0 && "End of list is not null?");
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}
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}
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void AliasSetTracker::removeAliasSet(AliasSet *AS) {
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if (AliasSet *Fwd = AS->Forward) {
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Fwd->dropRef(*this);
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AS->Forward = 0;
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}
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AliasSets.erase(AS);
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}
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void AliasSet::removeFromTracker(AliasSetTracker &AST) {
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assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
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AST.removeAliasSet(this);
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}
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void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
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unsigned Size, bool KnownMustAlias) {
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assert(!Entry.second.hasAliasSet() && "Entry already in set!");
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// Check to see if we have to downgrade to _may_ alias.
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if (isMustAlias() && !KnownMustAlias)
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if (HashNodePair *P = getSomePointer()) {
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AliasAnalysis &AA = AST.getAliasAnalysis();
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AliasAnalysis::AliasResult Result =
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AA.alias(P->first, P->second.getSize(), Entry.first, Size);
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if (Result == AliasAnalysis::MayAlias)
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AliasTy = MayAlias;
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else // First entry of must alias must have maximum size!
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P->second.updateSize(Size);
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assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
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}
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Entry.second.setAliasSet(this);
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Entry.second.updateSize(Size);
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// Add it to the end of the list...
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assert(*PtrListEnd == 0 && "End of list is not null?");
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*PtrListEnd = &Entry;
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PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
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assert(*PtrListEnd == 0 && "End of list is not null?");
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addRef(); // Entry points to alias set...
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}
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void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
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CallSites.push_back(CS);
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if (Function *F = CS.getCalledFunction()) {
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AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS);
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if (Behavior == AliasAnalysis::DoesNotAccessMemory)
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return;
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else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
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AliasTy = MayAlias;
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AccessTy |= Refs;
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return;
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}
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}
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// FIXME: This should use mod/ref information to make this not suck so bad
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AliasTy = MayAlias;
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AccessTy = ModRef;
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}
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/// aliasesPointer - Return true if the specified pointer "may" (or must)
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/// alias one of the members in the set.
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///
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bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
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AliasAnalysis &AA) const {
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if (AliasTy == MustAlias) {
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assert(CallSites.empty() && "Illegal must alias set!");
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// If this is a set of MustAliases, only check to see if the pointer aliases
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// SOME value in the set...
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HashNodePair *SomePtr = getSomePointer();
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assert(SomePtr && "Empty must-alias set??");
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return AA.alias(SomePtr->first, SomePtr->second.getSize(), Ptr, Size);
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}
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// If this is a may-alias set, we have to check all of the pointers in the set
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// to be sure it doesn't alias the set...
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for (iterator I = begin(), E = end(); I != E; ++I)
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if (AA.alias(Ptr, Size, I.getPointer(), I.getSize()))
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return true;
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// Check the call sites list and invoke list...
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if (!CallSites.empty()) {
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if (AA.hasNoModRefInfoForCalls())
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return true;
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for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
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if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size)
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!= AliasAnalysis::NoModRef)
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return true;
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}
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return false;
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}
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bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
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if (Function *F = CS.getCalledFunction())
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if (AA.doesNotAccessMemory(F))
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return false;
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if (AA.hasNoModRefInfoForCalls())
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return true;
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for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
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if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef ||
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AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef)
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return true;
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for (iterator I = begin(), E = end(); I != E; ++I)
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if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) !=
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AliasAnalysis::NoModRef)
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return true;
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return false;
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}
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/// findAliasSetForPointer - Given a pointer, find the one alias set to put the
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/// instruction referring to the pointer into. If there are multiple alias sets
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/// that may alias the pointer, merge them together and return the unified set.
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///
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AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
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unsigned Size) {
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AliasSet *FoundSet = 0;
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for (iterator I = begin(), E = end(); I != E; ++I)
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if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
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if (FoundSet == 0) { // If this is the first alias set ptr can go into.
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FoundSet = I; // Remember it.
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} else { // Otherwise, we must merge the sets.
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FoundSet->mergeSetIn(*I, *this); // Merge in contents.
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}
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}
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return FoundSet;
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}
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/// containsPointer - Return true if the specified location is represented by
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/// this alias set, false otherwise. This does not modify the AST object or
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/// alias sets.
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bool AliasSetTracker::containsPointer(Value *Ptr, unsigned Size) const {
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for (const_iterator I = begin(), E = end(); I != E; ++I)
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if (!I->Forward && I->aliasesPointer(Ptr, Size, AA))
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return true;
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return false;
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}
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AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
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AliasSet *FoundSet = 0;
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for (iterator I = begin(), E = end(); I != E; ++I)
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if (!I->Forward && I->aliasesCallSite(CS, AA)) {
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if (FoundSet == 0) { // If this is the first alias set ptr can go into.
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FoundSet = I; // Remember it.
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} else if (!I->Forward) { // Otherwise, we must merge the sets.
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FoundSet->mergeSetIn(*I, *this); // Merge in contents.
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}
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}
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return FoundSet;
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}
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/// getAliasSetForPointer - Return the alias set that the specified pointer
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/// lives in...
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AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size,
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bool *New) {
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AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
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// Check to see if the pointer is already known...
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if (Entry.second.hasAliasSet()) {
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Entry.second.updateSize(Size);
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// Return the set!
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return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
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} else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
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// Add it to the alias set it aliases...
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AS->addPointer(*this, Entry, Size);
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return *AS;
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} else {
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if (New) *New = true;
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// Otherwise create a new alias set to hold the loaded pointer...
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AliasSets.push_back(new AliasSet());
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AliasSets.back().addPointer(*this, Entry, Size);
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return AliasSets.back();
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}
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}
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bool AliasSetTracker::add(Value *Ptr, unsigned Size) {
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bool NewPtr;
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addPointer(Ptr, Size, AliasSet::NoModRef, NewPtr);
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return NewPtr;
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}
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bool AliasSetTracker::add(LoadInst *LI) {
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bool NewPtr;
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AliasSet &AS = addPointer(LI->getOperand(0),
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AA.getTargetData().getTypeSize(LI->getType()),
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AliasSet::Refs, NewPtr);
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if (LI->isVolatile()) AS.setVolatile();
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return NewPtr;
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}
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bool AliasSetTracker::add(StoreInst *SI) {
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bool NewPtr;
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Value *Val = SI->getOperand(0);
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AliasSet &AS = addPointer(SI->getOperand(1),
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AA.getTargetData().getTypeSize(Val->getType()),
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AliasSet::Mods, NewPtr);
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if (SI->isVolatile()) AS.setVolatile();
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return NewPtr;
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}
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bool AliasSetTracker::add(FreeInst *FI) {
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bool NewPtr;
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AliasSet &AS = addPointer(FI->getOperand(0), ~0,
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AliasSet::Mods, NewPtr);
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// Free operations are volatile ops (cannot be moved).
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AS.setVolatile();
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return NewPtr;
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}
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bool AliasSetTracker::add(CallSite CS) {
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if (Function *F = CS.getCalledFunction())
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if (AA.doesNotAccessMemory(F))
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return true; // doesn't alias anything
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AliasSet *AS = findAliasSetForCallSite(CS);
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if (!AS) {
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AliasSets.push_back(new AliasSet());
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AS = &AliasSets.back();
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AS->addCallSite(CS, AA);
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return true;
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} else {
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AS->addCallSite(CS, AA);
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return false;
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}
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}
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bool AliasSetTracker::add(Instruction *I) {
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// Dispatch to one of the other add methods...
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if (LoadInst *LI = dyn_cast<LoadInst>(I))
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return add(LI);
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else if (StoreInst *SI = dyn_cast<StoreInst>(I))
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return add(SI);
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else if (CallInst *CI = dyn_cast<CallInst>(I))
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return add(CI);
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else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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return add(II);
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else if (FreeInst *FI = dyn_cast<FreeInst>(I))
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return add(FI);
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return true;
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}
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void AliasSetTracker::add(BasicBlock &BB) {
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for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
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add(I);
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}
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void AliasSetTracker::add(const AliasSetTracker &AST) {
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assert(&AA == &AST.AA &&
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"Merging AliasSetTracker objects with different Alias Analyses!");
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// Loop over all of the alias sets in AST, adding the pointers contained
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// therein into the current alias sets. This can cause alias sets to be
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// merged together in the current AST.
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for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I)
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if (!I->Forward) { // Ignore forwarding alias sets
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AliasSet &AS = const_cast<AliasSet&>(*I);
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// If there are any call sites in the alias set, add them to this AST.
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for (unsigned i = 0, e = AS.CallSites.size(); i != e; ++i)
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add(AS.CallSites[i]);
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// Loop over all of the pointers in this alias set...
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AliasSet::iterator I = AS.begin(), E = AS.end();
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bool X;
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for (; I != E; ++I)
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addPointer(I.getPointer(), I.getSize(),
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(AliasSet::AccessType)AS.AccessTy, X);
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}
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}
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/// remove - Remove the specified (potentially non-empty) alias set from the
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/// tracker.
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void AliasSetTracker::remove(AliasSet &AS) {
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bool SetDead;
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do {
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AliasSet::iterator I = AS.begin();
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Value *Ptr = I.getPointer(); ++I;
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// deleteValue will delete the set automatically when the last pointer
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// reference is destroyed. "Predict" when this will happen.
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SetDead = I == AS.end();
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deleteValue(Ptr); // Delete all of the pointers from the set
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} while (!SetDead);
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}
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bool AliasSetTracker::remove(Value *Ptr, unsigned Size) {
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AliasSet *AS = findAliasSetForPointer(Ptr, Size);
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if (!AS) return false;
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remove(*AS);
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return true;
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}
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bool AliasSetTracker::remove(LoadInst *LI) {
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unsigned Size = AA.getTargetData().getTypeSize(LI->getType());
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AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size);
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if (!AS) return false;
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remove(*AS);
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return true;
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}
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bool AliasSetTracker::remove(StoreInst *SI) {
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unsigned Size = AA.getTargetData().getTypeSize(SI->getOperand(0)->getType());
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AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size);
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if (!AS) return false;
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remove(*AS);
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return true;
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}
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bool AliasSetTracker::remove(FreeInst *FI) {
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AliasSet *AS = findAliasSetForPointer(FI->getOperand(0), ~0);
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if (!AS) return false;
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remove(*AS);
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return true;
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}
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bool AliasSetTracker::remove(CallSite CS) {
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if (Function *F = CS.getCalledFunction())
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if (AA.doesNotAccessMemory(F))
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return false; // doesn't alias anything
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AliasSet *AS = findAliasSetForCallSite(CS);
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if (!AS) return false;
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remove(*AS);
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return true;
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}
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bool AliasSetTracker::remove(Instruction *I) {
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// Dispatch to one of the other remove methods...
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if (LoadInst *LI = dyn_cast<LoadInst>(I))
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return remove(LI);
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else if (StoreInst *SI = dyn_cast<StoreInst>(I))
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return remove(SI);
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else if (CallInst *CI = dyn_cast<CallInst>(I))
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return remove(CI);
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else if (FreeInst *FI = dyn_cast<FreeInst>(I))
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return remove(FI);
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return true;
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}
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// deleteValue method - This method is used to remove a pointer value from the
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// AliasSetTracker entirely. It should be used when an instruction is deleted
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// from the program to update the AST. If you don't use this, you would have
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// dangling pointers to deleted instructions.
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//
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void AliasSetTracker::deleteValue(Value *PtrVal) {
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// Notify the alias analysis implementation that this value is gone.
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AA.deleteValue(PtrVal);
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// First, look up the PointerRec for this pointer.
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hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
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if (I == PointerMap.end()) return; // Noop
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// If we found one, remove the pointer from the alias set it is in.
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AliasSet::HashNodePair &PtrValEnt = *I;
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AliasSet *AS = PtrValEnt.second.getAliasSet(*this);
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// Unlink from the list of values...
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PtrValEnt.second.removeFromList();
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// Stop using the alias set
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AS->dropRef(*this);
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PointerMap.erase(I);
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}
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// copyValue - This method should be used whenever a preexisting value in the
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// program is copied or cloned, introducing a new value. Note that it is ok for
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// clients that use this method to introduce the same value multiple times: if
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// the tracker already knows about a value, it will ignore the request.
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//
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void AliasSetTracker::copyValue(Value *From, Value *To) {
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// Notify the alias analysis implementation that this value is copied.
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AA.copyValue(From, To);
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// First, look up the PointerRec for this pointer.
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hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(From);
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if (I == PointerMap.end() || !I->second.hasAliasSet())
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return; // Noop
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AliasSet::HashNodePair &Entry = getEntryFor(To);
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if (Entry.second.hasAliasSet()) return; // Already in the tracker!
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// Add it to the alias set it aliases...
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AliasSet *AS = I->second.getAliasSet(*this);
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AS->addPointer(*this, Entry, I->second.getSize(), true);
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}
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//===----------------------------------------------------------------------===//
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// AliasSet/AliasSetTracker Printing Support
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//===----------------------------------------------------------------------===//
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void AliasSet::print(std::ostream &OS) const {
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OS << " AliasSet[" << (void*)this << "," << RefCount << "] ";
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OS << (AliasTy == MustAlias ? "must" : "may ") << " alias, ";
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switch (AccessTy) {
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case NoModRef: OS << "No access "; break;
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case Refs : OS << "Ref "; break;
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case Mods : OS << "Mod "; break;
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case ModRef : OS << "Mod/Ref "; break;
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default: assert(0 && "Bad value for AccessTy!");
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}
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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.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 (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);
|
|
Tracker->print(std::cerr);
|
|
delete Tracker;
|
|
return false;
|
|
}
|
|
};
|
|
RegisterOpt<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer");
|
|
}
|