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revision as I start to use it though. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3954 91177308-0d34-0410-b5e6-96231b3b80d8
173 lines
5.6 KiB
C++
173 lines
5.6 KiB
C++
//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
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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/iMemory.h"
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#include "llvm/iOther.h"
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#include "llvm/iTerminators.h"
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/// updateAccessTypes - Depending on what type of accesses are in this set,
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/// decide whether the set contains just references, just modifications, or a
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/// mix.
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///
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void AliasSet::updateAccessType() {
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if (!Calls.empty() || !Invokes.empty()) {
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AccessTy = ModRef;
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} else if (!Loads.empty()) {
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if (Stores.empty())
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AccessTy = Refs;
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else
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AccessTy = ModRef;
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} else {
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AccessTy = Mods;
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}
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}
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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(const AliasSet &AS) {
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// Merge instruction sets...
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Loads.insert( Loads.end(), AS.Loads.begin() , AS.Loads.end());
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Stores.insert( Stores.end(), AS.Stores.begin() , AS.Stores.end());
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Calls.insert( Calls.end(), AS.Calls.begin() , AS.Calls.end());
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Invokes.insert(Invokes.end(), AS.Invokes.begin(), AS.Invokes.end());
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// Update the alias and access types of this set...
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if (AS.getAliasType() == MayAlias)
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AliasTy = MayAlias;
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updateAccessType();
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}
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/// pointerAliasesSet - 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::pointerAliasesSet(const Value *Ptr, AliasAnalysis &AA) const {
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if (!Calls.empty() || !Invokes.empty())
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return true;
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for (unsigned i = 0, e = Loads.size(); i != e; ++i)
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if (AA.alias(Ptr, Loads[i]->getOperand(0)))
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return true;
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for (unsigned i = 0, e = Stores.size(); i != e; ++i)
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if (AA.alias(Ptr, Stores[i]->getOperand(1)))
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return true;
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return false;
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}
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/// getSomePointer - This method may only be called when the AliasType of the
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/// set is MustAlias. This is used to return any old pointer (which must alias
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/// all other pointers in the set) so that the caller can decide whether to turn
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/// this set into a may alias set or not.
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///
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Value *AliasSet::getSomePointer() const {
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assert(getAliasType() == MustAlias &&
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"Cannot call getSomePointer on a 'MayAlias' set!");
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assert(Calls.empty() && Invokes.empty() && "Call/invokes mean may alias!");
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if (!Loads.empty())
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return Loads[0]->getOperand(0);
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assert(!Stores.empty() && "There are no instructions in this set!");
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return Stores[0]->getOperand(1);
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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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AliasSet *FoundSet = 0;
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for (unsigned i = 0; i != AliasSets.size(); ++i) {
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if (AliasSets[i].pointerAliasesSet(Ptr, AA)) {
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if (FoundSet == 0) { // If this is the first alias set ptr can go into...
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FoundSet = &AliasSets[i]; // Remember it.
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} else { // Otherwise, we must merge the sets...
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FoundSet->mergeSetIn(AliasSets[i]); // Merge in contents...
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AliasSets.erase(AliasSets.begin()+i); // Remove the set...
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--i; // Don't skip the next set
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}
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}
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}
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return FoundSet;
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}
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void AliasSetTracker::add(LoadInst *LI) {
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Value *Pointer = LI->getOperand(0);
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// Check to see if the loaded pointer aliases any sets...
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AliasSet *AS = findAliasSetForPointer(Pointer);
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if (AS) {
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AS->Loads.push_back(LI);
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// Check to see if we need to change this into a MayAlias set now...
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if (AS->getAliasType() == AliasSet::MustAlias)
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if (AA.alias(AS->getSomePointer(), Pointer) != AliasAnalysis::MustAlias)
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AS->AliasTy = AliasSet::MayAlias;
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AS->updateAccessType();
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} else {
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// Otherwise create a new alias set to hold the load...
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AliasSets.push_back(AliasSet());
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AliasSets.back().Loads.push_back(LI);
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AliasSets.back().AccessTy = AliasSet::Refs;
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}
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}
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void AliasSetTracker::add(StoreInst *SI) {
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Value *Pointer = SI->getOperand(1);
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// Check to see if the loaded pointer aliases any sets...
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AliasSet *AS = findAliasSetForPointer(Pointer);
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if (AS) {
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AS->Stores.push_back(SI);
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// Check to see if we need to change this into a MayAlias set now...
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if (AS->getAliasType() == AliasSet::MustAlias)
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if (AA.alias(AS->getSomePointer(), Pointer) != AliasAnalysis::MustAlias)
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AS->AliasTy = AliasSet::MayAlias;
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AS->updateAccessType();
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} else {
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// Otherwise create a new alias set to hold the load...
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AliasSets.push_back(AliasSet());
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AliasSets.back().Stores.push_back(SI);
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AliasSets.back().AccessTy = AliasSet::Mods;
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}
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}
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void AliasSetTracker::mergeAllSets() {
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if (AliasSets.size() < 2) return; // Noop
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// Merge all of the sets into set #0
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for (unsigned i = 1, e = AliasSets.size(); i != e; ++i)
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AliasSets[0].mergeSetIn(AliasSets[i]);
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// Delete extraneous sets...
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AliasSets.erase(AliasSets.begin()+1, AliasSets.end());
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}
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void AliasSetTracker::add(CallInst *CI) {
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if (!AliasSets.empty()) {
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mergeAllSets();
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} else {
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AliasSets.push_back(AliasSet());
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}
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AliasSets[0].AccessTy = AliasSet::ModRef;
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AliasSets[0].AliasTy = AliasSet::MayAlias;
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AliasSets[0].Calls.push_back(CI);
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}
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void AliasSetTracker::add(InvokeInst *II) {
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if (!AliasSets.empty()) {
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mergeAllSets();
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} else {
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AliasSets.push_back(AliasSet());
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}
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AliasSets[0].AccessTy = AliasSet::ModRef;
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AliasSets[0].AliasTy = AliasSet::MayAlias;
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AliasSets[0].Invokes.push_back(II);
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}
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