/// RewriteUsesOfClonedInstructions - We just cloned the instructions from the
/// old header into the preheader. If there were uses of the values produced by
/// these instruction that were outside of the loop, we have to insert PHI nodes
/// to merge the two values. Do this now.
static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
BasicBlock *OrigPreheader,
ValueToValueMapTy &ValueMap) {
// Remove PHI node entries that are no longer live.
BasicBlock::iterator I, E = OrigHeader->end();
for (I = OrigHeader->begin(); PHINode *PN = dyn_cast<PHINode>(I); ++I)
PN->removeIncomingValue(PN->getBasicBlockIndex(OrigPreheader));
// Now fix up users of the instructions in OrigHeader, inserting PHI nodes
// as necessary.
SSAUpdater SSA;
for (I = OrigHeader->begin(); I != E; ++I) {
Value *OrigHeaderVal = I;
// If there are no uses of the value (e.g. because it returns void), there
// is nothing to rewrite.
if (OrigHeaderVal->use_empty())
continue;
Value *OrigPreHeaderVal = ValueMap[OrigHeaderVal];
// The value now exits in two versions: the initial value in the preheader
// and the loop "next" value in the original header.
SSA.Initialize(OrigHeaderVal->getType(), OrigHeaderVal->getName());
SSA.AddAvailableValue(OrigHeader, OrigHeaderVal);
SSA.AddAvailableValue(OrigPreheader, OrigPreHeaderVal);
// Visit each use of the OrigHeader instruction.
for (Value::use_iterator UI = OrigHeaderVal->use_begin(),
UE = OrigHeaderVal->use_end(); UI != UE; ) {
// Grab the use before incrementing the iterator.
Use &U = *UI;
// Increment the iterator before removing the use from the list.
++UI;
// SSAUpdater can't handle a non-PHI use in the same block as an
// earlier def. We can easily handle those cases manually.
Instruction *UserInst = cast<Instruction>(U.getUser());
if (!isa<PHINode>(UserInst)) {
BasicBlock *UserBB = UserInst->getParent();
// The original users in the OrigHeader are already using the
// original definitions.
if (UserBB == OrigHeader)
continue;
// Users in the OrigPreHeader need to use the value to which the
// original definitions are mapped.
if (UserBB == OrigPreheader) {
U = OrigPreHeaderVal;
continue;
}
}
// Anything else can be handled by SSAUpdater.
SSA.RewriteUse(U);
}
}
}
unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForAlloca(
const CodeMetrics &Metrics, Value *V) {
if (!V->getType()->isPointerTy()) return 0; // Not a pointer
unsigned Reduction = 0;
unsigned SROAReduction = 0;
bool CanSROAAlloca = true;
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI){
Instruction *I = cast<Instruction>(*UI);
if (ICmpInst *ICI = dyn_cast<ICmpInst>(I))
Reduction += countCodeReductionForAllocaICmp(Metrics, ICI);
if (CanSROAAlloca)
CanSROAAlloca = countCodeReductionForSROAInst(I, Worklist,
SROAReduction);
}
} while (!Worklist.empty());
return Reduction + (CanSROAAlloca ? SROAReduction : 0);
}
void GraphBuilder::visitPtrToIntInst(PtrToIntInst& I) {
DSNode* N = getValueDest(I.getOperand(0)).getNode();
if(I.hasOneUse()) {
if(isa<ICmpInst>(*(I.use_begin()))) {
NumBoringIntToPtr++;
return;
}
}
if(I.hasOneUse()) {
Value *V = dyn_cast<Value>(*(I.use_begin()));
DenseSet<Value *> Seen;
while(V && V->hasOneUse() &&
Seen.insert(V).second) {
if(isa<LoadInst>(V))
break;
if(isa<StoreInst>(V))
break;
if(isa<CallInst>(V))
break;
V = dyn_cast<Value>(*(V->use_begin()));
}
if(isa<BranchInst>(V)){
NumBoringIntToPtr++;
return;
}
}
if(N)
N->setPtrToIntMarker();
}
// GetTransitiveRedefinitions
// Returns the transitive closure of uses of the given variable that are
// redefinable. The instructions must dominate BB.
static void
GetTransitiveRedefinitions(Value *V, BasicBlock *BB, DominatorTree *DT,
set<Value*>& Redefinitions) {
assert(IsRedefinable(V) && "Parameter must be redefinable");
queue<Value*> Uses;
// Initialize the worklist with the given value.
Uses.push(V);
while (!Uses.empty()) {
Value *U = Uses.front();
assert(IsRedefinable(U) && "Value must be redefinable");
Uses.pop();
// Skip the visited values.
if (Redefinitions.count(U))
continue;
// Only redefine if the definition dominates the redefinition site.
if (Instruction *I = dyn_cast<Instruction>(U))
if (I->getParent() == BB || !DT->dominates(I->getParent(), BB))
continue;
// Insert the value into the redefinition list.
Redefinitions.insert(U);
// Add all its redefinable uses to the worklist.
for (auto UI = U->use_begin(), UE = U->use_end(); UI != UE; ++UI)
if (IsRedefinable(*UI))
Uses.push(*UI);
}
}
unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForConstant(
const CodeMetrics &Metrics, Value *V) {
unsigned Reduction = 0;
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
// We will be able to eliminate all but one of the successors.
const TerminatorInst &TI = cast<TerminatorInst>(*U);
const unsigned NumSucc = TI.getNumSuccessors();
unsigned Instrs = 0;
for (unsigned I = 0; I != NumSucc; ++I)
Instrs += Metrics.NumBBInsts.lookup(TI.getSuccessor(I));
// We don't know which blocks will be eliminated, so use the average size.
Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
continue;
}
// Figure out if this instruction will be removed due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
//
// FIXME: It would be nice to capture the fact that a load from a
// pointer-to-constant-global is actually a *really* good thing to zap.
// Unfortunately, we don't know the pointer that may get propagated here,
// so we can't make this decision.
if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
isa<AllocaInst>(Inst))
continue;
bool AllOperandsConstant = true;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
AllOperandsConstant = false;
break;
}
if (!AllOperandsConstant)
continue;
// We will get to remove this instruction...
Reduction += InlineConstants::InstrCost;
// And any other instructions that use it which become constants
// themselves.
Worklist.push_back(&Inst);
}
} while (!Worklist.empty());
return Reduction;
}
// Check if it is ok to perform this promotion.
bool SRETPromotion::isSafeToUpdateAllCallers(Function *F) {
if (F->use_empty())
// No users. OK to modify signature.
return true;
for (Value::use_iterator FnUseI = F->use_begin(), FnUseE = F->use_end();
FnUseI != FnUseE; ++FnUseI) {
// The function is passed in as an argument to (possibly) another function,
// we can't change it!
CallSite CS(*FnUseI);
Instruction *Call = CS.getInstruction();
// The function is used by something else than a call or invoke instruction,
// we can't change it!
if (!Call || !CS.isCallee(FnUseI))
return false;
CallSite::arg_iterator AI = CS.arg_begin();
Value *FirstArg = *AI;
if (!isa<AllocaInst>(FirstArg))
return false;
// Check FirstArg's users.
for (Value::use_iterator ArgI = FirstArg->use_begin(),
ArgE = FirstArg->use_end(); ArgI != ArgE; ++ArgI) {
User *U = *ArgI;
// If FirstArg user is a CallInst that does not correspond to current
// call site then this function F is not suitable for sret promotion.
if (CallInst *CI = dyn_cast<CallInst>(U)) {
if (CI != Call)
return false;
}
// If FirstArg user is a GEP whose all users are not LoadInst then
// this function F is not suitable for sret promotion.
else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
// TODO : Use dom info and insert PHINodes to collect get results
// from multiple call sites for this GEP.
if (GEP->getParent() != Call->getParent())
return false;
for (Value::use_iterator GEPI = GEP->use_begin(), GEPE = GEP->use_end();
GEPI != GEPE; ++GEPI)
if (!isa<LoadInst>(*GEPI))
return false;
}
// Any other FirstArg users make this function unsuitable for sret
// promotion.
else
return false;
}
}
return true;
}
void OptimizeReturned::visitCallSite(CallSite CS) {
for (unsigned i = 0, e = CS.getNumArgOperands(); i < e; ++i)
if (CS.paramHasAttr(1 + i, Attribute::Returned)) {
Instruction *Inst = CS.getInstruction();
Value *Arg = CS.getArgOperand(i);
// Ignore constants, globals, undef, etc.
if (isa<Constant>(Arg))
continue;
// Like replaceDominatedUsesWith but using Instruction/Use dominance.
for (auto UI = Arg->use_begin(), UE = Arg->use_end(); UI != UE;) {
Use &U = *UI++;
if (DT->dominates(Inst, U))
U.set(Inst);
}
}
}
// Predict that a comparison in which a register is an operand, the register is
// used before being defined in a successor block, and the successor block
// does not post-dominate will reach the successor block.
int BranchProbabilities::CheckGuardHeuristic()
{
BranchInst *BI = dyn_cast<BranchInst>(_TI);
bool bUses[2] = {false, false};
// If we don't have a conditional branch, abandon
if ((!BI) || (BI->isUnconditional()))
return -1;
// If the condition is not immediately dependent on a comparison, abandon
CmpInst *cmp = dyn_cast<CmpInst>(BI->getCondition());
if (!cmp)
return -1;
for (int i = 0; i < 2; i++)
{
if (_bPostDoms[i])
continue;
// Get the values being compared
Value *v = cmp->getOperand(i);
// For all uses of the first value check if the use post-dominates
for (Value::use_iterator UI = v->use_begin(), UE = v->use_end();
UI != UE; ++UI)
{
// if the use is not an instruction, skip it
Instruction *I = dyn_cast<Instruction>(*UI);
if (!I)
continue;
BasicBlock *UsingBlock = I->getParent();
// Check if the use is in either successor
for (int i = 0; i < 2; i++)
if (UsingBlock == _Succ[i])
bUses[i] = true;
}
}
if (bUses[0] == bUses[1])
return -1;
if (bUses[0])
return 0;
else
return 1;
}
bool LiveIRVariables::isLiveOut(Value &V, BasicBlock &BB) {
BasicBlock &DefBB = getDefiningBlock(V);
if (&DefBB == &BB) {
// If the value is defined within this basic block, just look for any use
// outside it.
for (Value::use_iterator UI = V.use_begin(),
UE = V.use_end(); UI != UE; ++UI) {
if (isa<Instruction>(*UI) && cast<Instruction>(*UI)->getParent() != &BB)
return true;
}
return false;
}
DominatorTree &DT = getAnalysis<DominatorTree>();
if (!DT.properlyDominates(&DefBB, &BB))
return false;
unsigned BBID = DFSOrdering.idFor(&BB) - 1;
BitVector &BackEdges = ReachableBackEdges[BBID];
bool BBIsBackEdgeTarget = isBackEdgeTarget(BB);
for (int i = BackEdges.find_first(); i != -1; i = BackEdges.find_next(i)) {
BasicBlock &ReachableBB = *DFSOrdering[i + 1];
// Ignore back edge targets that leave the dominance tree of def(V) and
// reenter it.
if (!DT.properlyDominates(&DefBB, &ReachableBB))
continue;
BitVector &ReachableBlocks = ReducedReachability[i];
for (int j = ReachableBlocks.find_first(); j != -1;
j = ReachableBlocks.find_next(j)) {
if ((unsigned)j == BBID && j == i && !BBIsBackEdgeTarget)
continue; // Skip trivial paths.
// FIXME: Precompute this to speed this up.
if (V.isUsedInBasicBlock(DFSOrdering[j + 1]))
return true;
}
}
return false;
}
// For each instruction used by the value, remove() the function that contains
// the instruction. This should happen right before a call to RAUW.
void MergeFunctions::removeUsers(Value *V) {
std::vector<Value *> Worklist;
Worklist.push_back(V);
while (!Worklist.empty()) {
Value *V = Worklist.back();
Worklist.pop_back();
for (Value::use_iterator UI = V->use_begin(), UE = V->use_end();
UI != UE; ++UI) {
Use &U = UI.getUse();
if (Instruction *I = dyn_cast<Instruction>(U.getUser())) {
remove(I->getParent()->getParent());
} else if (isa<GlobalValue>(U.getUser())) {
// do nothing
} else if (Constant *C = dyn_cast<Constant>(U.getUser())) {
for (Value::use_iterator CUI = C->use_begin(), CUE = C->use_end();
CUI != CUE; ++CUI)
Worklist.push_back(*CUI);
}
}
}
}
bool ObjCARCContract::runOnFunction(Function &F) {
if (!EnableARCOpts)
return false;
// If nothing in the Module uses ARC, don't do anything.
if (!Run)
return false;
Changed = false;
AA = &getAnalysis<AliasAnalysis>();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
PA.setAA(&getAnalysis<AliasAnalysis>());
DEBUG(llvm::dbgs() << "**** ObjCARC Contract ****\n");
// Track whether it's ok to mark objc_storeStrong calls with the "tail"
// keyword. Be conservative if the function has variadic arguments.
// It seems that functions which "return twice" are also unsafe for the
// "tail" argument, because they are setjmp, which could need to
// return to an earlier stack state.
bool TailOkForStoreStrongs =
!F.isVarArg() && !F.callsFunctionThatReturnsTwice();
// For ObjC library calls which return their argument, replace uses of the
// argument with uses of the call return value, if it dominates the use. This
// reduces register pressure.
SmallPtrSet<Instruction *, 4> DependingInstructions;
SmallPtrSet<const BasicBlock *, 4> Visited;
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E;) {
Instruction *Inst = &*I++;
DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
// First try to peephole Inst. If there is nothing further we can do in
// terms of undoing objc-arc-expand, process the next inst.
if (tryToPeepholeInstruction(F, Inst, I, DependingInstructions, Visited,
TailOkForStoreStrongs))
continue;
// Otherwise, try to undo objc-arc-expand.
// Don't use GetArgRCIdentityRoot because we don't want to look through bitcasts
// and such; to do the replacement, the argument must have type i8*.
Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
// TODO: Change this to a do-while.
for (;;) {
// If we're compiling bugpointed code, don't get in trouble.
if (!isa<Instruction>(Arg) && !isa<Argument>(Arg))
break;
// Look through the uses of the pointer.
for (Value::use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
UI != UE; ) {
// Increment UI now, because we may unlink its element.
Use &U = *UI++;
unsigned OperandNo = U.getOperandNo();
// If the call's return value dominates a use of the call's argument
// value, rewrite the use to use the return value. We check for
// reachability here because an unreachable call is considered to
// trivially dominate itself, which would lead us to rewriting its
// argument in terms of its return value, which would lead to
// infinite loops in GetArgRCIdentityRoot.
if (DT->isReachableFromEntry(U) && DT->dominates(Inst, U)) {
Changed = true;
Instruction *Replacement = Inst;
Type *UseTy = U.get()->getType();
if (PHINode *PHI = dyn_cast<PHINode>(U.getUser())) {
// For PHI nodes, insert the bitcast in the predecessor block.
unsigned ValNo = PHINode::getIncomingValueNumForOperand(OperandNo);
BasicBlock *BB = PHI->getIncomingBlock(ValNo);
if (Replacement->getType() != UseTy)
Replacement = new BitCastInst(Replacement, UseTy, "",
&BB->back());
// While we're here, rewrite all edges for this PHI, rather
// than just one use at a time, to minimize the number of
// bitcasts we emit.
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i)
if (PHI->getIncomingBlock(i) == BB) {
// Keep the UI iterator valid.
if (UI != UE &&
&PHI->getOperandUse(
PHINode::getOperandNumForIncomingValue(i)) == &*UI)
++UI;
PHI->setIncomingValue(i, Replacement);
}
} else {
if (Replacement->getType() != UseTy)
Replacement = new BitCastInst(Replacement, UseTy, "",
cast<Instruction>(U.getUser()));
U.set(Replacement);
}
}
}
// If Arg is a no-op casted pointer, strip one level of casts and iterate.
if (const BitCastInst *BI = dyn_cast<BitCastInst>(Arg))
Arg = BI->getOperand(0);
else if (isa<GEPOperator>(Arg) &&
cast<GEPOperator>(Arg)->hasAllZeroIndices())
Arg = cast<GEPOperator>(Arg)->getPointerOperand();
else if (isa<GlobalAlias>(Arg) &&
!cast<GlobalAlias>(Arg)->mayBeOverridden())
Arg = cast<GlobalAlias>(Arg)->getAliasee();
else
break;
}
}
// If this function has no escaping allocas or suspicious vararg usage,
// objc_storeStrong calls can be marked with the "tail" keyword.
if (TailOkForStoreStrongs)
for (CallInst *CI : StoreStrongCalls)
CI->setTailCall();
StoreStrongCalls.clear();
return Changed;
}
Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB,
BasicBlock *PredBB,
const DominatorTree *DT) {
// If this is a non-instruction value, it can't require PHI translation.
Instruction *Inst = dyn_cast<Instruction>(V);
if (Inst == 0) return V;
// Determine whether 'Inst' is an input to our PHI translatable expression.
bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst);
// Handle inputs instructions if needed.
if (isInput) {
if (Inst->getParent() != CurBB) {
// If it is an input defined in a different block, then it remains an
// input.
return Inst;
}
// If 'Inst' is defined in this block and is an input that needs to be phi
// translated, we need to incorporate the value into the expression or fail.
// In either case, the instruction itself isn't an input any longer.
InstInputs.erase(std::find(InstInputs.begin(), InstInputs.end(), Inst));
// If this is a PHI, go ahead and translate it.
if (PHINode *PN = dyn_cast<PHINode>(Inst))
return AddAsInput(PN->getIncomingValueForBlock(PredBB));
// If this is a non-phi value, and it is analyzable, we can incorporate it
// into the expression by making all instruction operands be inputs.
if (!CanPHITrans(Inst))
return 0;
// All instruction operands are now inputs (and of course, they may also be
// defined in this block, so they may need to be phi translated themselves.
for (unsigned i = 0, e = Inst->getNumOperands(); i != e; ++i)
if (Instruction *Op = dyn_cast<Instruction>(Inst->getOperand(i)))
InstInputs.push_back(Op);
}
// Ok, it must be an intermediate result (either because it started that way
// or because we just incorporated it into the expression). See if its
// operands need to be phi translated, and if so, reconstruct it.
if (CastInst *Cast = dyn_cast<CastInst>(Inst)) {
if (!isSafeToSpeculativelyExecute(Cast)) return 0;
Value *PHIIn = PHITranslateSubExpr(Cast->getOperand(0), CurBB, PredBB, DT);
if (PHIIn == 0) return 0;
if (PHIIn == Cast->getOperand(0))
return Cast;
// Find an available version of this cast.
// Constants are trivial to find.
if (Constant *C = dyn_cast<Constant>(PHIIn))
return AddAsInput(ConstantExpr::getCast(Cast->getOpcode(),
C, Cast->getType()));
// Otherwise we have to see if a casted version of the incoming pointer
// is available. If so, we can use it, otherwise we have to fail.
for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
UI != E; ++UI) {
if (CastInst *CastI = dyn_cast<CastInst>(*UI))
if (CastI->getOpcode() == Cast->getOpcode() &&
CastI->getType() == Cast->getType() &&
(!DT || DT->dominates(CastI->getParent(), PredBB)))
return CastI;
}
return 0;
}
// Handle getelementptr with at least one PHI translatable operand.
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
SmallVector<Value*, 8> GEPOps;
bool AnyChanged = false;
for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB, DT);
if (GEPOp == 0) return 0;
AnyChanged |= GEPOp != GEP->getOperand(i);
GEPOps.push_back(GEPOp);
}
if (!AnyChanged)
return GEP;
// Simplify the GEP to handle 'gep x, 0' -> x etc.
if (Value *V = SimplifyGEPInst(GEPOps, TD, TLI, DT)) {
for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
RemoveInstInputs(GEPOps[i], InstInputs);
return AddAsInput(V);
}
// Scan to see if we have this GEP available.
Value *APHIOp = GEPOps[0];
for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
UI != E; ++UI) {
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
if (GEPI->getType() == GEP->getType() &&
GEPI->getNumOperands() == GEPOps.size() &&
GEPI->getParent()->getParent() == CurBB->getParent() &&
(!DT || DT->dominates(GEPI->getParent(), PredBB))) {
bool Mismatch = false;
for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
if (GEPI->getOperand(i) != GEPOps[i]) {
Mismatch = true;
break;
}
if (!Mismatch)
return GEPI;
}
}
return 0;
}
// Handle add with a constant RHS.
if (Inst->getOpcode() == Instruction::Add &&
isa<ConstantInt>(Inst->getOperand(1))) {
// PHI translate the LHS.
Constant *RHS = cast<ConstantInt>(Inst->getOperand(1));
bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap();
bool isNUW = cast<BinaryOperator>(Inst)->hasNoUnsignedWrap();
Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB, DT);
if (LHS == 0) return 0;
// If the PHI translated LHS is an add of a constant, fold the immediates.
if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(LHS))
if (BOp->getOpcode() == Instruction::Add)
if (ConstantInt *CI = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
LHS = BOp->getOperand(0);
RHS = ConstantExpr::getAdd(RHS, CI);
isNSW = isNUW = false;
// If the old 'LHS' was an input, add the new 'LHS' as an input.
if (std::count(InstInputs.begin(), InstInputs.end(), BOp)) {
RemoveInstInputs(BOp, InstInputs);
AddAsInput(LHS);
}
}
// See if the add simplifies away.
if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD, TLI, DT)) {
// If we simplified the operands, the LHS is no longer an input, but Res
// is.
RemoveInstInputs(LHS, InstInputs);
return AddAsInput(Res);
}
// If we didn't modify the add, just return it.
if (LHS == Inst->getOperand(0) && RHS == Inst->getOperand(1))
return Inst;
// Otherwise, see if we have this add available somewhere.
for (Value::use_iterator UI = LHS->use_begin(), E = LHS->use_end();
UI != E; ++UI) {
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(*UI))
if (BO->getOpcode() == Instruction::Add &&
BO->getOperand(0) == LHS && BO->getOperand(1) == RHS &&
BO->getParent()->getParent() == CurBB->getParent() &&
(!DT || DT->dominates(BO->getParent(), PredBB)))
return BO;
}
return 0;
}
// Otherwise, we failed.
return 0;
}
void* MCJITHelper::dynamicInlinerForOpenOSR(Function* F1, Instruction* OSRSrc, void* extra, void* profDataAddr) {
DynamicInlinerInfo* inlineInfo = (DynamicInlinerInfo*) extra;
MCJITHelper* TheHelper = inlineInfo->TheHelper;
bool verbose = TheHelper->verbose;
assert(OSRSrc->getParent()->getParent() == F1 && "MCJIT messed up the objects");
if (verbose) {
std::cerr << "Value for F1 is " << F1 << std::endl;
std::cerr << "Value for OSRSrc is " << OSRSrc << std::endl;
std::cerr << "Value for extra is " << extra << std::endl;
std::cerr << "Value for profDataAddr is " << profDataAddr << std::endl;
}
std::pair<Function*, StateMap*> identityPair = StateMap::generateIdentityMapping(F1);
Function* F2 = identityPair.first;
StateMap* M = identityPair.second;
Value* valToInlineInF2 = M->getCorrespondingOneToOneValue(inlineInfo->valToInline);
Instruction* OSRSrcInF2 = cast<Instruction>(M->getCorrespondingOneToOneValue(OSRSrc));
assert (OSRSrcInF2 != nullptr && "TODO cannot find corresponding OSRSrc in temporary F2");
if (OSRLibrary::removeOSRPoint(*OSRSrcInF2) && verbose) {
std::cerr << "OSR point removed after cloning F1" << std::endl;
}
Instruction* LPad = M->getLandingPad(OSRSrc);
StateMap* M_F2toOSRContFun;
LivenessAnalysis LA(F1);
std::vector<Value*>* valuesToPass = OSRLibrary::getLiveValsVecAtInstr(OSRSrc, LA);
std::string OSRDestFunName = (F2->getName().str()).append("OSRCont");
Function* OSRContFun = OSRLibrary::genContinuationFunc(TheHelper->Context,
*F1, *F2, *OSRSrc, *LPad, *valuesToPass, *M, &OSRDestFunName, verbose, &M_F2toOSRContFun);
Value* valToInline = M_F2toOSRContFun->getCorrespondingOneToOneValue(valToInlineInF2);
assert (valToInline != nullptr && "broken state map for continuation function");
delete valuesToPass;
delete F2;
delete M;
delete M_F2toOSRContFun;
// create a module for generated code
std::string modForJITName = "OpenOSRDynInline";
modForJITName.append(OSRDestFunName);
std::unique_ptr<Module> modForJIT = llvm::make_unique<Module>(modForJITName, TheHelper->Context);
Module* modForJIT_ptr = modForJIT.get();
// determine which function is called
uint64_t calledFun = (uint64_t)profDataAddr;
std::cerr << "Address of invoked function: " << calledFun << std::endl;
Function* funToInline = nullptr;
for (AddrSymPair &pair: TheHelper->CompiledFunAddrTable) {
if (pair.first == calledFun) {
std::string &FunName = pair.second;
funToInline = TheHelper->getFunction(FunName);
break;
}
}
Function* myFunToInline = nullptr;
if (funToInline == nullptr) {
std::cerr << "Sorry, I could not determine which function was called!" << std::endl;
} else {
std::cerr << "Function being inlined: " << funToInline->getName().str() << std::endl;
ValueToValueMapTy VMap;
myFunToInline = CloneFunction(funToInline, VMap, false, nullptr);
myFunToInline->addFnAttr(Attribute::AlwaysInline);
myFunToInline->setLinkage(Function::LinkageTypes::PrivateLinkage);
modForJIT_ptr->getFunctionList().push_back(myFunToInline);
OSRLibrary::fixUsesOfFunctionsAndGlobals(funToInline, myFunToInline);
for (Value::use_iterator UI = valToInline->use_begin(),
UE = valToInline->use_end(); UI != UE; ) {
Use &U = *(UI++);
if (CallInst* CI = dyn_cast<CallInst>(U.getUser())) {
if (CI->getParent()->getParent() != OSRContFun) continue;
if (verbose) {
raw_os_ostream errStream(std::cerr);
std::cerr << "Updating instruction ";
CI->print(errStream);
std::cerr << std::endl;
}
U.set(myFunToInline);
}
}
}
modForJIT_ptr->getFunctionList().push_back(OSRContFun);
verifyFunction(*OSRContFun, &outs());
// remove dead code & inline when possible
FunctionPassManager FPM(modForJIT_ptr);
FPM.add(createCFGSimplificationPass());
FPM.doInitialization();
FPM.run(*OSRContFun);
if (funToInline != nullptr) {
PassManager PM;
PM.add(llvm::createAlwaysInlinerPass());
PM.run(*modForJIT_ptr);
}
// compile code
TheHelper->addModule(std::move(modForJIT));
return (void*)TheHelper->JIT->getFunctionAddress(OSRDestFunName);
}
/// FindPromotableValuesInLoop - Check the current loop for stores to definite
/// pointers, which are not loaded and stored through may aliases and are safe
/// for promotion. If these are found, create an alloca for the value, add it
/// to the PromotedValues list, and keep track of the mapping from value to
/// alloca.
void LICM::FindPromotableValuesInLoop(
std::vector<std::pair<AllocaInst*, Value*> > &PromotedValues,
std::map<Value*, AllocaInst*> &ValueToAllocaMap) {
Instruction *FnStart = CurLoop->getHeader()->getParent()->begin()->begin();
// Loop over all of the alias sets in the tracker object.
for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
I != E; ++I) {
AliasSet &AS = *I;
// We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores.
if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->getValue()))
continue;
assert(!AS.empty() &&
"Must alias set should have at least one pointer element in it!");
Value *V = AS.begin()->getValue();
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
{
bool PointerOk = true;
for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I)
if (V->getType() != I->getValue()->getType()) {
PointerOk = false;
break;
}
if (!PointerOk)
continue;
}
// It isn't safe to promote a load/store from the loop if the load/store is
// conditional. For example, turning:
//
// for () { if (c) *P += 1; }
//
// into:
//
// tmp = *P; for () { if (c) tmp +=1; } *P = tmp;
//
// is not safe, because *P may only be valid to access if 'c' is true.
//
// It is safe to promote P if all uses are direct load/stores and if at
// least one is guaranteed to be executed.
bool GuaranteedToExecute = false;
bool InvalidInst = false;
for (Value::use_iterator UI = V->use_begin(), UE = V->use_end();
UI != UE; ++UI) {
// Ignore instructions not in this loop.
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use->getParent()))
continue;
if (!isa<LoadInst>(Use) && !isa<StoreInst>(Use)) {
InvalidInst = true;
break;
}
if (!GuaranteedToExecute)
GuaranteedToExecute = isSafeToExecuteUnconditionally(*Use);
}
// If there is an non-load/store instruction in the loop, we can't promote
// it. If there isn't a guaranteed-to-execute instruction, we can't
// promote.
if (InvalidInst || !GuaranteedToExecute)
continue;
const Type *Ty = cast<PointerType>(V->getType())->getElementType();
AllocaInst *AI = new AllocaInst(Ty, 0, V->getName()+".tmp", FnStart);
PromotedValues.push_back(std::make_pair(AI, V));
// Update the AST and alias analysis.
CurAST->copyValue(V, AI);
for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I)
ValueToAllocaMap.insert(std::make_pair(I->getValue(), AI));
DEBUG(errs() << "LICM: Promoting value: " << *V << "\n");
}
}
/// PromoteValuesInLoop - Try to promote memory values to scalars by sinking
/// stores out of the loop and moving loads to before the loop. We do this by
/// looping over the stores in the loop, looking for stores to Must pointers
/// which are loop invariant. We promote these memory locations to use allocas
/// instead. These allocas can easily be raised to register values by the
/// PromoteMem2Reg functionality.
///
void LICM::PromoteValuesInLoop() {
// PromotedValues - List of values that are promoted out of the loop. Each
// value has an alloca instruction for it, and a canonical version of the
// pointer.
std::vector<std::pair<AllocaInst*, Value*> > PromotedValues;
std::map<Value*, AllocaInst*> ValueToAllocaMap; // Map of ptr to alloca
FindPromotableValuesInLoop(PromotedValues, ValueToAllocaMap);
if (ValueToAllocaMap.empty()) return; // If there are values to promote.
Changed = true;
NumPromoted += PromotedValues.size();
std::vector<Value*> PointerValueNumbers;
// Emit a copy from the value into the alloca'd value in the loop preheader
TerminatorInst *LoopPredInst = Preheader->getTerminator();
for (unsigned i = 0, e = PromotedValues.size(); i != e; ++i) {
Value *Ptr = PromotedValues[i].second;
// If we are promoting a pointer value, update alias information for the
// inserted load.
Value *LoadValue = 0;
if (isa<PointerType>(cast<PointerType>(Ptr->getType())->getElementType())) {
// Locate a load or store through the pointer, and assign the same value
// to LI as we are loading or storing. Since we know that the value is
// stored in this loop, this will always succeed.
for (Value::use_iterator UI = Ptr->use_begin(), E = Ptr->use_end();
UI != E; ++UI)
if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) {
LoadValue = LI;
break;
} else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) {
if (SI->getOperand(1) == Ptr) {
LoadValue = SI->getOperand(0);
break;
}
}
assert(LoadValue && "No store through the pointer found!");
PointerValueNumbers.push_back(LoadValue); // Remember this for later.
}
// Load from the memory we are promoting.
LoadInst *LI = new LoadInst(Ptr, Ptr->getName()+".promoted", LoopPredInst);
if (LoadValue) CurAST->copyValue(LoadValue, LI);
// Store into the temporary alloca.
new StoreInst(LI, PromotedValues[i].first, LoopPredInst);
}
// Scan the basic blocks in the loop, replacing uses of our pointers with
// uses of the allocas in question.
//
for (Loop::block_iterator I = CurLoop->block_begin(),
E = CurLoop->block_end(); I != E; ++I) {
BasicBlock *BB = *I;
// Rewrite all loads and stores in the block of the pointer...
for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
if (LoadInst *L = dyn_cast<LoadInst>(II)) {
std::map<Value*, AllocaInst*>::iterator
I = ValueToAllocaMap.find(L->getOperand(0));
if (I != ValueToAllocaMap.end())
L->setOperand(0, I->second); // Rewrite load instruction...
} else if (StoreInst *S = dyn_cast<StoreInst>(II)) {
std::map<Value*, AllocaInst*>::iterator
I = ValueToAllocaMap.find(S->getOperand(1));
if (I != ValueToAllocaMap.end())
S->setOperand(1, I->second); // Rewrite store instruction...
}
}
}
// Now that the body of the loop uses the allocas instead of the original
// memory locations, insert code to copy the alloca value back into the
// original memory location on all exits from the loop. Note that we only
// want to insert one copy of the code in each exit block, though the loop may
// exit to the same block more than once.
//
SmallPtrSet<BasicBlock*, 16> ProcessedBlocks;
SmallVector<BasicBlock*, 8> ExitBlocks;
CurLoop->getExitBlocks(ExitBlocks);
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
if (!ProcessedBlocks.insert(ExitBlocks[i]))
continue;
// Copy all of the allocas into their memory locations.
BasicBlock::iterator BI = ExitBlocks[i]->getFirstNonPHI();
Instruction *InsertPos = BI;
unsigned PVN = 0;
for (unsigned i = 0, e = PromotedValues.size(); i != e; ++i) {
// Load from the alloca.
LoadInst *LI = new LoadInst(PromotedValues[i].first, "", InsertPos);
// If this is a pointer type, update alias info appropriately.
if (isa<PointerType>(LI->getType()))
CurAST->copyValue(PointerValueNumbers[PVN++], LI);
// Store into the memory we promoted.
new StoreInst(LI, PromotedValues[i].second, InsertPos);
}
}
// Now that we have done the deed, use the mem2reg functionality to promote
// all of the new allocas we just created into real SSA registers.
//
std::vector<AllocaInst*> PromotedAllocas;
PromotedAllocas.reserve(PromotedValues.size());
for (unsigned i = 0, e = PromotedValues.size(); i != e; ++i)
PromotedAllocas.push_back(PromotedValues[i].first);
PromoteMemToReg(PromotedAllocas, *DT, *DF, CurAST);
}
/// PromoteAliasSet - Try to promote memory values to scalars by sinking
/// stores out of the loop and moving loads to before the loop. We do this by
/// looping over the stores in the loop, looking for stores to Must pointers
/// which are loop invariant.
///
void LICM::PromoteAliasSet(AliasSet &AS) {
// We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores.
if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->getValue()))
return;
assert(!AS.empty() &&
"Must alias set should have at least one pointer element in it!");
Value *SomePtr = AS.begin()->getValue();
// It isn't safe to promote a load/store from the loop if the load/store is
// conditional. For example, turning:
//
// for () { if (c) *P += 1; }
//
// into:
//
// tmp = *P; for () { if (c) tmp +=1; } *P = tmp;
//
// is not safe, because *P may only be valid to access if 'c' is true.
//
// It is safe to promote P if all uses are direct load/stores and if at
// least one is guaranteed to be executed.
bool GuaranteedToExecute = false;
SmallVector<Instruction*, 64> LoopUses;
SmallPtrSet<Value*, 4> PointerMustAliases;
// We start with an alignment of one and try to find instructions that allow
// us to prove better alignment.
unsigned Alignment = 1;
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
Value *ASIV = ASI->getValue();
PointerMustAliases.insert(ASIV);
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
if (SomePtr->getType() != ASIV->getType())
return;
for (Value::use_iterator UI = ASIV->use_begin(), UE = ASIV->use_end();
UI != UE; ++UI) {
// Ignore instructions that are outside the loop.
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use))
continue;
// If there is an non-load/store instruction in the loop, we can't promote
// it.
if (LoadInst *load = dyn_cast<LoadInst>(Use)) {
assert(!load->isVolatile() && "AST broken");
if (!load->isSimple())
return;
} else if (StoreInst *store = dyn_cast<StoreInst>(Use)) {
// Stores *of* the pointer are not interesting, only stores *to* the
// pointer.
if (Use->getOperand(1) != ASIV)
continue;
assert(!store->isVolatile() && "AST broken");
if (!store->isSimple())
return;
// Note that we only check GuaranteedToExecute inside the store case
// so that we do not introduce stores where they did not exist before
// (which would break the LLVM concurrency model).
// If the alignment of this instruction allows us to specify a more
// restrictive (and performant) alignment and if we are sure this
// instruction will be executed, update the alignment.
// Larger is better, with the exception of 0 being the best alignment.
unsigned InstAlignment = store->getAlignment();
if ((InstAlignment > Alignment || InstAlignment == 0)
&& (Alignment != 0))
if (isGuaranteedToExecute(*Use)) {
GuaranteedToExecute = true;
Alignment = InstAlignment;
}
if (!GuaranteedToExecute)
GuaranteedToExecute = isGuaranteedToExecute(*Use);
} else
return; // Not a load or store.
LoopUses.push_back(Use);
}
}
// If there isn't a guaranteed-to-execute instruction, we can't promote.
if (!GuaranteedToExecute)
return;
// Otherwise, this is safe to promote, lets do it!
DEBUG(dbgs() << "LICM: Promoting value stored to in loop: " <<*SomePtr<<'\n');
Changed = true;
++NumPromoted;
// Grab a debug location for the inserted loads/stores; given that the
// inserted loads/stores have little relation to the original loads/stores,
// this code just arbitrarily picks a location from one, since any debug
// location is better than none.
DebugLoc DL = LoopUses[0]->getDebugLoc();
SmallVector<BasicBlock*, 8> ExitBlocks;
CurLoop->getUniqueExitBlocks(ExitBlocks);
// We use the SSAUpdater interface to insert phi nodes as required.
SmallVector<PHINode*, 16> NewPHIs;
SSAUpdater SSA(&NewPHIs);
LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks,
*CurAST, DL, Alignment);
// Set up the preheader to have a definition of the value. It is the live-out
// value from the preheader that uses in the loop will use.
LoadInst *PreheaderLoad =
new LoadInst(SomePtr, SomePtr->getName()+".promoted",
Preheader->getTerminator());
PreheaderLoad->setAlignment(Alignment);
PreheaderLoad->setDebugLoc(DL);
SSA.AddAvailableValue(Preheader, PreheaderLoad);
// Rewrite all the loads in the loop and remember all the definitions from
// stores in the loop.
Promoter.run(LoopUses);
// If the SSAUpdater didn't use the load in the preheader, just zap it now.
if (PreheaderLoad->use_empty())
PreheaderLoad->eraseFromParent();
}
/*
* Renaming uses of V to uses of vSSA_PHI
* The rule of renaming is:
* - All uses of V in the dominator tree of vSSA_PHI are renamed
* - Uses of V in the same basicblock of vSSA_PHI are only renamed if they are not in PHI functions
* - Uses of V in the dominance frontier follow the same rules of sigma renaming
*/
void vSSA::renameUsesToPhi(Value *V, PHINode *phi)
{
// This vector of Instruction* points to the uses of operand.
// This auxiliary vector of pointers is used because the use_iterators are invalidated when we do the renaming
SmallVector<Instruction*, 25> usepointers;
unsigned i = 0, n = V->getNumUses();
usepointers.resize(n);
// This vector contains pointers to all sigmas that have its operand renamed to vSSA_phi
// For them, we need to try to create phi functions again
SmallVector<PHINode*, 25> sigmasRenamed;
BasicBlock *BB_next = phi->getParent();
// Get the dominance frontier of the successor
DominanceFrontier::iterator DF_BB = DF_->find(BB_next);
for (Value::use_iterator uit = V->use_begin(), uend = V->use_end(); uit != uend; ++uit, ++i)
usepointers[i] = dyn_cast<Instruction>(*uit);
BasicBlock *BB_parent = phi->getParent();
for (i = 0; i < n; ++i) {
// Check if the use is in the dominator tree of vSSA_PHI
if (DT_->dominates(BB_parent, usepointers[i]->getParent())) {
if (BB_parent != usepointers[i]->getParent()) {
usepointers[i]->replaceUsesOfWith(V, phi);
// If this use is in a sigma, we need to check whether phis creation are needed again for this sigma
if (PHINode *sigma = dyn_cast<PHINode>(usepointers[i])) {
if (sigma->getName().startswith(vSSA_SIG)) {
sigmasRenamed.push_back(sigma);
}
}
}
else if (!isa<PHINode>(usepointers[i]))
usepointers[i]->replaceUsesOfWith(V, phi);
}
// Check if the use is in the dominance frontier of phi
else if (DF_BB->second.find(usepointers[i]->getParent()) != DF_BB->second.end()) {
// Check if the user is a PHI node (it has to be, but only for precaution)
if (PHINode *phiuser = dyn_cast<PHINode>(usepointers[i])) {
for (unsigned i = 0, e = phiuser->getNumIncomingValues(); i < e; ++i) {
Value *operand = phiuser->getIncomingValue(i);
if (operand != V)
continue;
if (DT_->dominates(BB_next, phiuser->getIncomingBlock(i))) {
phiuser->setIncomingValue(i, phi);
}
}
}
}
}
for (unsigned k = 0, f = phi->getNumIncomingValues(); k < f; ++k) {
PHINode *p = dyn_cast<PHINode>(phi->getIncomingValue(k));
if (!p || !p->getName().startswith(vSSA_SIG))
continue;
Value *V = p->getIncomingValue(0);
n = V->getNumUses();
usepointers.resize(n);
unsigned i = 0;
for (Value::use_iterator uit = V->use_begin(), uend = V->use_end(); uit != uend; ++uit, ++i)
usepointers[i] = dyn_cast<Instruction>(*uit);
for (i = 0; i < n; ++i) {
// Check if the use is in the dominator tree of vSSA_PHI
if (DT_->dominates(BB_parent, usepointers[i]->getParent())) {
if (BB_parent != usepointers[i]->getParent()) {
usepointers[i]->replaceUsesOfWith(V, phi);
// If this use is in a sigma, we need to check whether phis creation are needed again for this sigma
if (PHINode *sigma = dyn_cast<PHINode>(usepointers[i])) {
if (sigma->getName().startswith(vSSA_SIG)) {
sigmasRenamed.push_back(sigma);
}
}
}
else if (!isa<PHINode>(usepointers[i]))
usepointers[i]->replaceUsesOfWith(V, phi);
}
// Check if the use is in the dominance frontier of phi
else if (DF_BB->second.find(usepointers[i]->getParent()) != DF_BB->second.end()) {
// Check if the user is a PHI node (it has to be, but only for precaution)
if (PHINode *phiuser = dyn_cast<PHINode>(usepointers[i])) {
for (unsigned i = 0, e = phiuser->getNumIncomingValues(); i < e; ++i) {
Value *operand = phiuser->getIncomingValue(i);
if (operand != V)
continue;
if (DT_->dominates(BB_next, phiuser->getIncomingBlock(i))) {
phiuser->setIncomingValue(i, phi);
}
}
}
}
}
}
// Try to create phis again for the sigmas whose operand was renamed to vSSA_phi
// Also, renaming may need to be done again
for (SmallVectorImpl<PHINode*>::iterator vit = sigmasRenamed.begin(), vend = sigmasRenamed.end(); vit != vend; ++vit) {
renameUsesToSigma(phi, *vit);
SmallVector<PHINode*, 25> vssaphis_created = insertPhisForSigma(phi, *vit);
//insertSigmaAsOperandOfPhis(vssaphis_created, *vit);
populatePhis(vssaphis_created, (*vit)->getIncomingValue(0));
}
// Creation of phis may require the creation of sigmas that were not created previosly, so we do it now
createSigmasIfNeeded(phi->getParent());
}
/// updateCallSites - Update all sites that call F to use NF.
CallGraphNode *SRETPromotion::updateCallSites(Function *F, Function *NF) {
CallGraph &CG = getAnalysis<CallGraph>();
SmallVector<Value*, 16> Args;
// Attributes - Keep track of the parameter attributes for the arguments.
SmallVector<AttributeWithIndex, 8> ArgAttrsVec;
// Get a new callgraph node for NF.
CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF);
while (!F->use_empty()) {
CallSite CS(*F->use_begin());
Instruction *Call = CS.getInstruction();
const AttrListPtr &PAL = F->getAttributes();
// Add any return attributes.
if (Attributes attrs = PAL.getRetAttributes())
ArgAttrsVec.push_back(AttributeWithIndex::get(0, attrs));
// Copy arguments, however skip first one.
CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
Value *FirstCArg = *AI;
++AI;
// 0th parameter attribute is reserved for return type.
// 1th parameter attribute is for first 1st sret argument.
unsigned ParamIndex = 2;
while (AI != AE) {
Args.push_back(*AI);
if (Attributes Attrs = PAL.getParamAttributes(ParamIndex))
ArgAttrsVec.push_back(AttributeWithIndex::get(ParamIndex - 1, Attrs));
++ParamIndex;
++AI;
}
// Add any function attributes.
if (Attributes attrs = PAL.getFnAttributes())
ArgAttrsVec.push_back(AttributeWithIndex::get(~0, attrs));
AttrListPtr NewPAL = AttrListPtr::get(ArgAttrsVec.begin(), ArgAttrsVec.end());
// Build new call instruction.
Instruction *New;
if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
Args.begin(), Args.end(), "", Call);
cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
cast<InvokeInst>(New)->setAttributes(NewPAL);
} else {
New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call);
cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
cast<CallInst>(New)->setAttributes(NewPAL);
if (cast<CallInst>(Call)->isTailCall())
cast<CallInst>(New)->setTailCall();
}
Args.clear();
ArgAttrsVec.clear();
New->takeName(Call);
// Update the callgraph to know that the callsite has been transformed.
CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()];
CalleeNode->removeCallEdgeFor(Call);
CalleeNode->addCalledFunction(New, NF_CGN);
// Update all users of sret parameter to extract value using extractvalue.
for (Value::use_iterator UI = FirstCArg->use_begin(),
UE = FirstCArg->use_end(); UI != UE; ) {
User *U2 = *UI++;
CallInst *C2 = dyn_cast<CallInst>(U2);
if (C2 && (C2 == Call))
continue;
GetElementPtrInst *UGEP = cast<GetElementPtrInst>(U2);
ConstantInt *Idx = cast<ConstantInt>(UGEP->getOperand(2));
Value *GR = ExtractValueInst::Create(New, Idx->getZExtValue(),
"evi", UGEP);
while(!UGEP->use_empty()) {
// isSafeToUpdateAllCallers has checked that all GEP uses are
// LoadInsts
LoadInst *L = cast<LoadInst>(*UGEP->use_begin());
L->replaceAllUsesWith(GR);
L->eraseFromParent();
}
UGEP->eraseFromParent();
continue;
}
Call->eraseFromParent();
}
return NF_CGN;
}
//
// Method: registerAllocaInst()
//
// Description:
// Register a single alloca instruction.
//
// Inputs:
// AI - The alloca which requires registration.
//
// Return value:
// NULL - The alloca was not registered.
// Otherwise, the call to poolregister() is returned.
//
CallInst *
RegisterStackObjPass::registerAllocaInst (AllocaInst *AI) {
//
// Determine if any use (direct or indirect) escapes this function. If
// not, then none of the checks will consult the MetaPool, and we can
// forego registering the alloca.
//
#if 0
bool MustRegisterAlloca = false;
#else
//
// FIXME: For now, register all allocas. The reason is that this
// optimization requires that other optimizations be executed, and those are
// not integrated into LLVM yet.
//
bool MustRegisterAlloca = true;
#endif
std::vector<Value *> AllocaWorkList;
AllocaWorkList.push_back (AI);
while ((!MustRegisterAlloca) && (AllocaWorkList.size())) {
Value * V = AllocaWorkList.back();
AllocaWorkList.pop_back();
Value::use_iterator UI = V->use_begin();
for (; UI != V->use_end(); ++UI) {
// We cannot handle PHI nodes or Select instructions
if (isa<PHINode>(*UI) || isa<SelectInst>(*UI)) {
MustRegisterAlloca = true;
continue;
}
// The pointer escapes if it's stored to memory somewhere.
StoreInst * SI;
if ((SI = dyn_cast<StoreInst>(*UI)) && (SI->getOperand(0) == V)) {
MustRegisterAlloca = true;
continue;
}
// GEP instructions are okay, but need to be added to the worklist
if (isa<GetElementPtrInst>(*UI)) {
AllocaWorkList.push_back (*UI);
continue;
}
// Cast instructions are okay as long as they cast to another pointer
// type
if (CastInst * CI = dyn_cast<CastInst>(*UI)) {
if (isa<PointerType>(CI->getType())) {
AllocaWorkList.push_back (*UI);
continue;
} else {
MustRegisterAlloca = true;
continue;
}
}
#if 0
if (ConstantExpr *cExpr = dyn_cast<ConstantExpr>(*UI)) {
if (cExpr->getOpcode() == Instruction::Cast) {
AllocaWorkList.push_back (*UI);
continue;
} else {
MustRegisterAlloca = true;
continue;
}
}
#endif
CallInst * CI1;
if ((CI1 = dyn_cast<CallInst>(*UI))) {
if (!(CI1->getCalledFunction())) {
MustRegisterAlloca = true;
continue;
}
std::string FuncName = CI1->getCalledFunction()->getName();
if (FuncName == "exactcheck3") {
AllocaWorkList.push_back (*UI);
continue;
} else if ((FuncName == "llvm.memcpy.i32") ||
(FuncName == "llvm.memcpy.i64") ||
(FuncName == "llvm.memset.i32") ||
(FuncName == "llvm.memset.i64") ||
(FuncName == "llvm.memmove.i32") ||
(FuncName == "llvm.memmove.i64") ||
(FuncName == "llva_memcpy") ||
(FuncName == "llva_memset") ||
(FuncName == "llva_strncpy") ||
(FuncName == "llva_invokememcpy") ||
(FuncName == "llva_invokestrncpy") ||
(FuncName == "llva_invokememset") ||
(FuncName == "memcmp")) {
continue;
} else {
MustRegisterAlloca = true;
continue;
}
}
}
}
if (!MustRegisterAlloca) {
++SavedRegAllocs;
return 0;
}
//
// Insert the alloca registration.
//
//
// Create an LLVM Value for the allocation size. Insert a multiplication
// instruction if the allocation allocates an array.
//
Type * Int32Type = IntegerType::getInt32Ty(AI->getContext());
unsigned allocsize = TD->getTypeAllocSize(AI->getAllocatedType());
Value *AllocSize = ConstantInt::get (AI->getOperand(0)->getType(), allocsize);
if (AI->isArrayAllocation()) {
Value * Operand = AI->getOperand(0);
AllocSize = BinaryOperator::Create(Instruction::Mul,
AllocSize,
Operand,
"sizetmp",
AI);
}
AllocSize = castTo (AllocSize, Int32Type, "sizetmp", AI);
//
// Attempt to insert the call to register the alloca'ed object after all of
// the alloca instructions in the basic block.
//
Instruction *iptI = AI;
BasicBlock::iterator InsertPt = AI;
iptI = ++InsertPt;
if (AI->getParent() == (&(AI->getParent()->getParent()->getEntryBlock()))) {
InsertPt = AI->getParent()->begin();
while (&(*(InsertPt)) != AI)
++InsertPt;
while (isa<AllocaInst>(InsertPt))
++InsertPt;
iptI = InsertPt;
}
//
// Insert a call to register the object.
//
PointerType * VoidPtrTy = getVoidPtrType(AI->getContext());
Instruction *Casted = castTo (AI, VoidPtrTy, AI->getName()+".casted", iptI);
Value * CastedPH = ConstantPointerNull::get (VoidPtrTy);
std::vector<Value *> args;
args.push_back (CastedPH);
args.push_back (Casted);
args.push_back (AllocSize);
// Update statistics
++StackRegisters;
return CallInst::Create (PoolRegister, args, "", iptI);
}
/// RewriteUsesOfClonedInstructions - We just cloned the instructions from the
/// old header into the preheader. If there were uses of the values produced by
/// these instruction that were outside of the loop, we have to insert PHI nodes
/// to merge the two values. Do this now.
static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
BasicBlock *OrigPreheader,
ValueToValueMapTy &ValueMap,
SmallVectorImpl<PHINode*> *InsertedPHIs) {
// Remove PHI node entries that are no longer live.
BasicBlock::iterator I, E = OrigHeader->end();
for (I = OrigHeader->begin(); PHINode *PN = dyn_cast<PHINode>(I); ++I)
PN->removeIncomingValue(PN->getBasicBlockIndex(OrigPreheader));
// Now fix up users of the instructions in OrigHeader, inserting PHI nodes
// as necessary.
SSAUpdater SSA(InsertedPHIs);
for (I = OrigHeader->begin(); I != E; ++I) {
Value *OrigHeaderVal = &*I;
// If there are no uses of the value (e.g. because it returns void), there
// is nothing to rewrite.
if (OrigHeaderVal->use_empty())
continue;
Value *OrigPreHeaderVal = ValueMap.lookup(OrigHeaderVal);
// The value now exits in two versions: the initial value in the preheader
// and the loop "next" value in the original header.
SSA.Initialize(OrigHeaderVal->getType(), OrigHeaderVal->getName());
SSA.AddAvailableValue(OrigHeader, OrigHeaderVal);
SSA.AddAvailableValue(OrigPreheader, OrigPreHeaderVal);
// Visit each use of the OrigHeader instruction.
for (Value::use_iterator UI = OrigHeaderVal->use_begin(),
UE = OrigHeaderVal->use_end();
UI != UE;) {
// Grab the use before incrementing the iterator.
Use &U = *UI;
// Increment the iterator before removing the use from the list.
++UI;
// SSAUpdater can't handle a non-PHI use in the same block as an
// earlier def. We can easily handle those cases manually.
Instruction *UserInst = cast<Instruction>(U.getUser());
if (!isa<PHINode>(UserInst)) {
BasicBlock *UserBB = UserInst->getParent();
// The original users in the OrigHeader are already using the
// original definitions.
if (UserBB == OrigHeader)
continue;
// Users in the OrigPreHeader need to use the value to which the
// original definitions are mapped.
if (UserBB == OrigPreheader) {
U = OrigPreHeaderVal;
continue;
}
}
// Anything else can be handled by SSAUpdater.
SSA.RewriteUse(U);
}
// Replace MetadataAsValue(ValueAsMetadata(OrigHeaderVal)) uses in debug
// intrinsics.
SmallVector<DbgValueInst *, 1> DbgValues;
llvm::findDbgValues(DbgValues, OrigHeaderVal);
for (auto &DbgValue : DbgValues) {
// The original users in the OrigHeader are already using the original
// definitions.
BasicBlock *UserBB = DbgValue->getParent();
if (UserBB == OrigHeader)
continue;
// Users in the OrigPreHeader need to use the value to which the
// original definitions are mapped and anything else can be handled by
// the SSAUpdater. To avoid adding PHINodes, check if the value is
// available in UserBB, if not substitute undef.
Value *NewVal;
if (UserBB == OrigPreheader)
NewVal = OrigPreHeaderVal;
else if (SSA.HasValueForBlock(UserBB))
NewVal = SSA.GetValueInMiddleOfBlock(UserBB);
else
NewVal = UndefValue::get(OrigHeaderVal->getType());
DbgValue->setOperand(0,
MetadataAsValue::get(OrigHeaderVal->getContext(),
ValueAsMetadata::get(NewVal)));
}
}
}
Value* LoopTripCount::insertTripCount(Loop* L, Instruction* InsertPos)
{
// inspired from Loop::getCanonicalInductionVariable
BasicBlock *H = L->getHeader();
BasicBlock* LoopPred = L->getLoopPredecessor();
BasicBlock* startBB = NULL;//which basicblock stores start value
int OneStep = 0;// the extra add or plus step for calc
Assert(LoopPred, "Require Loop has a Pred");
DEBUG(errs()<<"loop depth:"<<L->getLoopDepth()<<"\n");
/** whats difference on use of predecessor and preheader??*/
//RET_ON_FAIL(self->getLoopLatch()&&self->getLoopPreheader());
//assert(self->getLoopLatch() && self->getLoopPreheader() && "need loop simplify form" );
ret_null_fail(L->getLoopLatch(), "need loop simplify form");
BasicBlock* TE = NULL;//True Exit
SmallVector<BasicBlock*,4> Exits;
L->getExitingBlocks(Exits);
if(Exits.size()==1) TE = Exits.front();
else{
if(std::find(Exits.begin(),Exits.end(),L->getLoopLatch())!=Exits.end()) TE = L->getLoopLatch();
else{
SmallVector<llvm::Loop::Edge,4> ExitEdges;
L->getExitEdges(ExitEdges);
//stl 用法,先把所有满足条件的元素(出口的结束符是不可到达)移动到数组的末尾,再统一删除
ExitEdges.erase(std::remove_if(ExitEdges.begin(), ExitEdges.end(),
[](llvm::Loop::Edge& I){
return isa<UnreachableInst>(I.second->getTerminator());
}), ExitEdges.end());
if(ExitEdges.size()==1) TE = const_cast<BasicBlock*>(ExitEdges.front().first);
}
}
//process true exit
ret_null_fail(TE, "need have a true exit");
Instruction* IndOrNext = NULL;
Value* END = NULL;
//终止块的终止指令：分情况讨论branchinst,switchinst;
//跳转指令br bool a1,a2;condition<-->bool
if(isa<BranchInst>(TE->getTerminator())){
const BranchInst* EBR = cast<BranchInst>(TE->getTerminator());
Assert(EBR->isConditional(), "end branch is not conditional");
ICmpInst* EC = dyn_cast<ICmpInst>(EBR->getCondition());
if(EC->getPredicate() == EC->ICMP_SGT){
Assert(!L->contains(EBR->getSuccessor(0)), *EBR<<":abnormal exit with great than");//终止块的终止指令---->跳出执行循环外的指令
OneStep += 1;
} else if(EC->getPredicate() == EC->ICMP_EQ)
Assert(!L->contains(EBR->getSuccessor(0)), *EBR<<":abnormal exit with great than");
else if(EC->getPredicate() == EC->ICMP_SLT) {
ret_null_fail(!L->contains(EBR->getSuccessor(1)), *EBR<<":abnormal exit with less than");
} else {
ret_null_fail(0, *EC<<" unknow combination of end condition");
}
IndOrNext = dyn_cast<Instruction>(castoff(EC->getOperand(0)));//去掉类型转化
END = EC->getOperand(1);
DEBUG(errs()<<"end value:"<<*EC<<"\n");
}else if(isa<SwitchInst>(TE->getTerminator())){
SwitchInst* ESW = const_cast<SwitchInst*>(cast<SwitchInst>(TE->getTerminator()));
IndOrNext = dyn_cast<Instruction>(castoff(ESW->getCondition()));
for(auto I = ESW->case_begin(),E = ESW->case_end();I!=E;++I){
if(!L->contains(I.getCaseSuccessor())){
ret_null_fail(!END,"");
assert(!END && "shouldn't have two ends");
END = I.getCaseValue();
}
}
DEBUG(errs()<<"end value:"<<*ESW<<"\n");
}else{
assert(0 && "unknow terminator type");
}
ret_null_fail(L->isLoopInvariant(END), "end value should be loop invariant");//至此得END值
Value* start = NULL;
Value* ind = NULL;
Instruction* next = NULL;
bool addfirst = false;//add before icmp ed
DISABLE(errs()<<*IndOrNext<<"\n");
if(isa<LoadInst>(IndOrNext)){
//memory depend analysis
Value* PSi = IndOrNext->getOperand(0);//point type Step.i
int SICount[2] = {0};//store in predecessor count,store in loop body count
for( auto I = PSi->use_begin(),E = PSi->use_end();I!=E;++I){
DISABLE(errs()<<**I<<"\n");
StoreInst* SI = dyn_cast<StoreInst>(*I);
if(!SI || SI->getOperand(1) != PSi) continue;
if(!start&&L->isLoopInvariant(SI->getOperand(0))) {
if(SI->getParent() != LoopPred)
if(std::find(pred_begin(LoopPred),pred_end(LoopPred),SI->getParent()) == pred_end(LoopPred)) continue;
start = SI->getOperand(0);
startBB = SI->getParent();
++SICount[0];
}
Instruction* SI0 = dyn_cast<Instruction>(SI->getOperand(0));
if(L->contains(SI) && SI0 && SI0->getOpcode() == Instruction::Add){
next = SI0;
++SICount[1];
}
}
Assert(SICount[0]==1 && SICount[1]==1, "");
ind = IndOrNext;
}else{
if(isa<PHINode>(IndOrNext)){
PHINode* PHI = cast<PHINode>(IndOrNext);
ind = IndOrNext;
if(castoff(PHI->getIncomingValue(0)) == castoff(PHI->getIncomingValue(1)) && PHI->getParent() != H)
ind = castoff(PHI->getIncomingValue(0));
addfirst = false;
}else if(IndOrNext->getOpcode() == Instruction::Add){
next = IndOrNext;
addfirst = true;
}else{
Assert(0 ,"unknow how to analysis");
}
for(auto I = H->begin();isa<PHINode>(I);++I){
PHINode* P = cast<PHINode>(I);
if(ind && P == ind){
//start = P->getIncomingValueForBlock(L->getLoopPredecessor());
start = tryFindStart(P, L, startBB);
next = dyn_cast<Instruction>(P->getIncomingValueForBlock(L->getLoopLatch()));
}else if(next && P->getIncomingValueForBlock(L->getLoopLatch()) == next){
//start = P->getIncomingValueForBlock(L->getLoopPredecessor());
start = tryFindStart(P, L, startBB);
ind = P;
}
}
}
Assert(start ,"couldn't find a start value");
//process complex loops later
//DEBUG(if(L->getLoopDepth()>1 || !L->getSubLoops().empty()) return NULL);
DEBUG(errs()<<"start value:"<<*start<<"\n");
DEBUG(errs()<<"ind value:"<<*ind<<"\n");
DEBUG(errs()<<"next value:"<<*next<<"\n");
//process non add later
unsigned next_phi_idx = 0;
ConstantInt* Step = NULL,*PrevStep = NULL;/*only used if next is phi node*/
ret_null_fail(next, "");
PHINode* next_phi = dyn_cast<PHINode>(next);
do{
if(next_phi) {
next = dyn_cast<Instruction>(next_phi->getIncomingValue(next_phi_idx));
ret_null_fail(next, "");
DEBUG(errs()<<"next phi "<<next_phi_idx<<":"<<*next<<"\n");
if(Step&&PrevStep){
Assert(Step->getSExtValue() == PrevStep->getSExtValue(),"");
}
PrevStep = Step;
}
Assert(next->getOpcode() == Instruction::Add , "why induction increment is not Add");
Assert(next->getOperand(0) == ind ,"why induction increment is not add it self");
Step = dyn_cast<ConstantInt>(next->getOperand(1));
Assert(Step,"");
}while(next_phi && ++next_phi_idx<next_phi->getNumIncomingValues());
//RET_ON_FAIL(Step->equalsInt(1));
//assert(VERBOSE(Step->equalsInt(1),Step) && "why induction increment number is not 1");
Value* RES = NULL;
//if there are no predecessor, we can insert code into start value basicblock
IRBuilder<> Builder(InsertPos);
Assert(start->getType()->isIntegerTy() && END->getType()->isIntegerTy() , " why increment is not integer type");
if(start->getType() != END->getType()){
start = Builder.CreateCast(CastInst::getCastOpcode(start, false,
END->getType(), false),start,END->getType());
}
if(Step->getType() != END->getType()){
//Because Step is a Constant, so it casted is constant
Step = dyn_cast<ConstantInt>(Builder.CreateCast(CastInst::getCastOpcode(Step, false,
END->getType(), false),Step,END->getType()));
AssertRuntime(Step);
}
if(Step->isMinusOne())
RES = Builder.CreateSub(start,END);
else//Step Couldn't be zero
RES = Builder.CreateSub(END, start);
if(addfirst) OneStep -= 1;
if(Step->isMinusOne()) OneStep*=-1;
assert(OneStep<=1 && OneStep>=-1);
RES = (OneStep==1)?Builder.CreateAdd(RES,Step):(OneStep==-1)?Builder.CreateSub(RES, Step):RES;
if(!Step->isMinusOne()&&!Step->isOne())
RES = Builder.CreateSDiv(RES, Step);
RES->setName(H->getName()+".tc");
return RES;
}
/// PromoteAliasSet - Try to promote memory values to scalars by sinking
/// stores out of the loop and moving loads to before the loop. We do this by
/// looping over the stores in the loop, looking for stores to Must pointers
/// which are loop invariant.
///
void LICM::PromoteAliasSet(AliasSet &AS) {
// We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores.
if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->getValue()))
return;
assert(!AS.empty() &&
"Must alias set should have at least one pointer element in it!");
Value *SomePtr = AS.begin()->getValue();
// It isn't safe to promote a load/store from the loop if the load/store is
// conditional. For example, turning:
//
// for () { if (c) *P += 1; }
//
// into:
//
// tmp = *P; for () { if (c) tmp +=1; } *P = tmp;
//
// is not safe, because *P may only be valid to access if 'c' is true.
//
// It is safe to promote P if all uses are direct load/stores and if at
// least one is guaranteed to be executed.
bool GuaranteedToExecute = false;
SmallVector<Instruction*, 64> LoopUses;
SmallPtrSet<Value*, 4> PointerMustAliases;
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
Value *ASIV = ASI->getValue();
PointerMustAliases.insert(ASIV);
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
if (SomePtr->getType() != ASIV->getType())
return;
for (Value::use_iterator UI = ASIV->use_begin(), UE = ASIV->use_end();
UI != UE; ++UI) {
// Ignore instructions that are outside the loop.
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use))
continue;
// If there is an non-load/store instruction in the loop, we can't promote
// it.
if (isa<LoadInst>(Use))
assert(!cast<LoadInst>(Use)->isVolatile() && "AST broken");
else if (isa<StoreInst>(Use)) {
assert(!cast<StoreInst>(Use)->isVolatile() && "AST broken");
if (Use->getOperand(0) == ASIV) return;
} else
return; // Not a load or store.
if (!GuaranteedToExecute)
GuaranteedToExecute = isSafeToExecuteUnconditionally(*Use);
LoopUses.push_back(Use);
}
}
// If there isn't a guaranteed-to-execute instruction, we can't promote.
if (!GuaranteedToExecute)
return;
// Otherwise, this is safe to promote, lets do it!
DEBUG(dbgs() << "LICM: Promoting value stored to in loop: " <<*SomePtr<<'\n');
Changed = true;
++NumPromoted;
// We use the SSAUpdater interface to insert phi nodes as required.
SmallVector<PHINode*, 16> NewPHIs;
SSAUpdater SSA(&NewPHIs);
// It wants to know some value of the same type as what we'll be inserting.
Value *SomeValue;
if (isa<LoadInst>(LoopUses[0]))
SomeValue = LoopUses[0];
else
SomeValue = cast<StoreInst>(LoopUses[0])->getOperand(0);
SSA.Initialize(SomeValue->getType(), SomeValue->getName());
// First step: bucket up uses of the pointers by the block they occur in.
// This is important because we have to handle multiple defs/uses in a block
// ourselves: SSAUpdater is purely for cross-block references.
// FIXME: Want a TinyVector<Instruction*> since there is usually 0/1 element.
DenseMap<BasicBlock*, std::vector<Instruction*> > UsesByBlock;
for (unsigned i = 0, e = LoopUses.size(); i != e; ++i) {
Instruction *User = LoopUses[i];
UsesByBlock[User->getParent()].push_back(User);
}
// Okay, now we can iterate over all the blocks in the loop with uses,
// processing them. Keep track of which loads are loading a live-in value.
SmallVector<LoadInst*, 32> LiveInLoads;
DenseMap<Value*, Value*> ReplacedLoads;
for (unsigned LoopUse = 0, e = LoopUses.size(); LoopUse != e; ++LoopUse) {
Instruction *User = LoopUses[LoopUse];
std::vector<Instruction*> &BlockUses = UsesByBlock[User->getParent()];
// If this block has already been processed, ignore this repeat use.
if (BlockUses.empty()) continue;
// Okay, this is the first use in the block. If this block just has a
// single user in it, we can rewrite it trivially.
if (BlockUses.size() == 1) {
// If it is a store, it is a trivial def of the value in the block.
if (isa<StoreInst>(User)) {
SSA.AddAvailableValue(User->getParent(),
cast<StoreInst>(User)->getOperand(0));
} else {
// Otherwise it is a load, queue it to rewrite as a live-in load.
LiveInLoads.push_back(cast<LoadInst>(User));
}
BlockUses.clear();
continue;
}
// Otherwise, check to see if this block is all loads. If so, we can queue
// them all as live in loads.
bool HasStore = false;
for (unsigned i = 0, e = BlockUses.size(); i != e; ++i) {
if (isa<StoreInst>(BlockUses[i])) {
HasStore = true;
break;
}
}
if (!HasStore) {
for (unsigned i = 0, e = BlockUses.size(); i != e; ++i)
LiveInLoads.push_back(cast<LoadInst>(BlockUses[i]));
BlockUses.clear();
continue;
}
// Otherwise, we have mixed loads and stores (or just a bunch of stores).
// Since SSAUpdater is purely for cross-block values, we need to determine
// the order of these instructions in the block. If the first use in the
// block is a load, then it uses the live in value. The last store defines
// the live out value. We handle this by doing a linear scan of the block.
BasicBlock *BB = User->getParent();
Value *StoredValue = 0;
for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
if (LoadInst *L = dyn_cast<LoadInst>(II)) {
// If this is a load from an unrelated pointer, ignore it.
if (!PointerMustAliases.count(L->getOperand(0))) continue;
// If we haven't seen a store yet, this is a live in use, otherwise
// use the stored value.
if (StoredValue) {
L->replaceAllUsesWith(StoredValue);
ReplacedLoads[L] = StoredValue;
} else {
LiveInLoads.push_back(L);
}
continue;
}
if (StoreInst *S = dyn_cast<StoreInst>(II)) {
// If this is a store to an unrelated pointer, ignore it.
if (!PointerMustAliases.count(S->getOperand(1))) continue;
// Remember that this is the active value in the block.
StoredValue = S->getOperand(0);
}
}
// The last stored value that happened is the live-out for the block.
assert(StoredValue && "Already checked that there is a store in block");
SSA.AddAvailableValue(BB, StoredValue);
BlockUses.clear();
}
// Now that all the intra-loop values are classified, set up the preheader.
// It gets a load of the pointer we're promoting, and it is the live-out value
// from the preheader.
LoadInst *PreheaderLoad = new LoadInst(SomePtr,SomePtr->getName()+".promoted",
Preheader->getTerminator());
SSA.AddAvailableValue(Preheader, PreheaderLoad);
// Now that the preheader is good to go, set up the exit blocks. Each exit
// block gets a store of the live-out values that feed them. Since we've
// already told the SSA updater about the defs in the loop and the preheader
// definition, it is all set and we can start using it.
SmallVector<BasicBlock*, 8> ExitBlocks;
CurLoop->getUniqueExitBlocks(ExitBlocks);
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
BasicBlock *ExitBlock = ExitBlocks[i];
Value *LiveInValue = SSA.GetValueInMiddleOfBlock(ExitBlock);
Instruction *InsertPos = ExitBlock->getFirstNonPHI();
new StoreInst(LiveInValue, SomePtr, InsertPos);
}
// Okay, now we rewrite all loads that use live-in values in the loop,
// inserting PHI nodes as necessary.
for (unsigned i = 0, e = LiveInLoads.size(); i != e; ++i) {
LoadInst *ALoad = LiveInLoads[i];
Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
ALoad->replaceAllUsesWith(NewVal);
CurAST->copyValue(ALoad, NewVal);
ReplacedLoads[ALoad] = NewVal;
}
// If the preheader load is itself a pointer, we need to tell alias analysis
// about the new pointer we created in the preheader block and about any PHI
// nodes that just got inserted.
if (PreheaderLoad->getType()->isPointerTy()) {
// Copy any value stored to or loaded from a must-alias of the pointer.
CurAST->copyValue(SomeValue, PreheaderLoad);
for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i)
CurAST->copyValue(SomeValue, NewPHIs[i]);
}
// Now that everything is rewritten, delete the old instructions from the body
// of the loop. They should all be dead now.
for (unsigned i = 0, e = LoopUses.size(); i != e; ++i) {
Instruction *User = LoopUses[i];
// If this is a load that still has uses, then the load must have been added
// as a live value in the SSAUpdate data structure for a block (e.g. because
// the loaded value was stored later). In this case, we need to recursively
// propagate the updates until we get to the real value.
if (!User->use_empty()) {
Value *NewVal = ReplacedLoads[User];
assert(NewVal && "not a replaced load?");
// Propagate down to the ultimate replacee. The intermediately loads
// could theoretically already have been deleted, so we don't want to
// dereference the Value*'s.
DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal);
while (RLI != ReplacedLoads.end()) {
NewVal = RLI->second;
RLI = ReplacedLoads.find(NewVal);
}
User->replaceAllUsesWith(NewVal);
CurAST->copyValue(User, NewVal);
}
CurAST->deleteValue(User);
User->eraseFromParent();
}
// fwew, we're done!
}
bool InferAddressSpaces::rewriteWithNewAddressSpaces(
ArrayRef<WeakTrackingVH> Postorder,
const ValueToAddrSpaceMapTy &InferredAddrSpace, Function *F) const {
// For each address expression to be modified, creates a clone of it with its
// pointer operands converted to the new address space. Since the pointer
// operands are converted, the clone is naturally in the new address space by
// construction.
ValueToValueMapTy ValueWithNewAddrSpace;
SmallVector<const Use *, 32> UndefUsesToFix;
for (Value* V : Postorder) {
unsigned NewAddrSpace = InferredAddrSpace.lookup(V);
if (V->getType()->getPointerAddressSpace() != NewAddrSpace) {
ValueWithNewAddrSpace[V] = cloneValueWithNewAddressSpace(
V, NewAddrSpace, ValueWithNewAddrSpace, &UndefUsesToFix);
}
}
if (ValueWithNewAddrSpace.empty())
return false;
// Fixes all the undef uses generated by cloneInstructionWithNewAddressSpace.
for (const Use *UndefUse : UndefUsesToFix) {
User *V = UndefUse->getUser();
User *NewV = cast<User>(ValueWithNewAddrSpace.lookup(V));
unsigned OperandNo = UndefUse->getOperandNo();
assert(isa<UndefValue>(NewV->getOperand(OperandNo)));
NewV->setOperand(OperandNo, ValueWithNewAddrSpace.lookup(UndefUse->get()));
}
SmallVector<Instruction *, 16> DeadInstructions;
// Replaces the uses of the old address expressions with the new ones.
for (const WeakTrackingVH &WVH : Postorder) {
assert(WVH && "value was unexpectedly deleted");
Value *V = WVH;
Value *NewV = ValueWithNewAddrSpace.lookup(V);
if (NewV == nullptr)
continue;
DEBUG(dbgs() << "Replacing the uses of " << *V
<< "\n with\n " << *NewV << '\n');
if (Constant *C = dyn_cast<Constant>(V)) {
Constant *Replace = ConstantExpr::getAddrSpaceCast(cast<Constant>(NewV),
C->getType());
if (C != Replace) {
DEBUG(dbgs() << "Inserting replacement const cast: "
<< Replace << ": " << *Replace << '\n');
C->replaceAllUsesWith(Replace);
V = Replace;
}
}
Value::use_iterator I, E, Next;
for (I = V->use_begin(), E = V->use_end(); I != E; ) {
Use &U = *I;
// Some users may see the same pointer operand in multiple operands. Skip
// to the next instruction.
I = skipToNextUser(I, E);
if (isSimplePointerUseValidToReplace(U)) {
// If V is used as the pointer operand of a compatible memory operation,
// sets the pointer operand to NewV. This replacement does not change
// the element type, so the resultant load/store is still valid.
U.set(NewV);
continue;
}
User *CurUser = U.getUser();
// Handle more complex cases like intrinsic that need to be remangled.
if (auto *MI = dyn_cast<MemIntrinsic>(CurUser)) {
if (!MI->isVolatile() && handleMemIntrinsicPtrUse(MI, V, NewV))
continue;
}
if (auto *II = dyn_cast<IntrinsicInst>(CurUser)) {
if (rewriteIntrinsicOperands(II, V, NewV))
continue;
}
if (isa<Instruction>(CurUser)) {
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(CurUser)) {
// If we can infer that both pointers are in the same addrspace,
// transform e.g.
// %cmp = icmp eq float* %p, %q
// into
// %cmp = icmp eq float addrspace(3)* %new_p, %new_q
unsigned NewAS = NewV->getType()->getPointerAddressSpace();
int SrcIdx = U.getOperandNo();
int OtherIdx = (SrcIdx == 0) ? 1 : 0;
Value *OtherSrc = Cmp->getOperand(OtherIdx);
if (Value *OtherNewV = ValueWithNewAddrSpace.lookup(OtherSrc)) {
if (OtherNewV->getType()->getPointerAddressSpace() == NewAS) {
Cmp->setOperand(OtherIdx, OtherNewV);
Cmp->setOperand(SrcIdx, NewV);
continue;
}
}
// Even if the type mismatches, we can cast the constant.
if (auto *KOtherSrc = dyn_cast<Constant>(OtherSrc)) {
if (isSafeToCastConstAddrSpace(KOtherSrc, NewAS)) {
Cmp->setOperand(SrcIdx, NewV);
Cmp->setOperand(OtherIdx,
ConstantExpr::getAddrSpaceCast(KOtherSrc, NewV->getType()));
continue;
}
}
}
if (AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(CurUser)) {
unsigned NewAS = NewV->getType()->getPointerAddressSpace();
if (ASC->getDestAddressSpace() == NewAS) {
ASC->replaceAllUsesWith(NewV);
DeadInstructions.push_back(ASC);
continue;
}
}
// Otherwise, replaces the use with flat(NewV).
if (Instruction *I = dyn_cast<Instruction>(V)) {
BasicBlock::iterator InsertPos = std::next(I->getIterator());
while (isa<PHINode>(InsertPos))
++InsertPos;
U.set(new AddrSpaceCastInst(NewV, V->getType(), "", &*InsertPos));
} else {
U.set(ConstantExpr::getAddrSpaceCast(cast<Constant>(NewV),
V->getType()));
}
}
}
if (V->use_empty()) {
if (Instruction *I = dyn_cast<Instruction>(V))
DeadInstructions.push_back(I);
}
}
for (Instruction *I : DeadInstructions)
RecursivelyDeleteTriviallyDeadInstructions(I);
return true;
}
//
// Method: processFunction()
//
// Description:
// This method searches for calls to a specified run-time check. For every
// such call, it replaces the pointer that the call checks with the return
// value of the call.
//
// This allows functions like boundscheck() to return a rewrite pointer;
// this code changes the program to use the returned rewrite pointer instead
// of the original pointer which was passed into boundscheck().
//
// Inputs:
// M - The module to modify.
// Check - A reference to a structure describing the checking function to
// process.
//
// Return value:
// false - No modifications were made to the Module.
// true - One or more modifications were made to the module.
//
bool
RewriteOOB::processFunction (Module & M, const CheckInfo & Check) {
//
// Get a pointer to the checking function. If the checking function does
// not exist within the program, then do nothing.
//
Function * F = M.getFunction (Check.name);
if (!F)
return false;
//
// Ensure the function has the right number of arguments and that its
// result is a pointer type.
//
assert (isa<PointerType>(F->getReturnType()));
//
// To avoid recalculating the dominator information each time we process a
// use of the specified function F, we will record the function containing
// the call instruction to F and the corresponding dominator information; we
// will then update this information only when the next use is a call
// instruction belonging to a different function. We are helped by the fact
// that iterating through uses often groups uses within the same function.
//
Function * CurrentFunction = 0;
DominatorTree * domTree = 0;
//
// Iterate though all calls to the function and modify the use of the
// operand to be the result of the function.
//
bool modified = false;
for (Value::use_iterator FU = F->use_begin(); FU != F->use_end(); ++FU) {
//
// We are only concerned about call instructions; any other use is of
// no interest to the organization.
//
if (CallInst * CI = dyn_cast<CallInst>(*FU)) {
//
// We're going to make a change. Mark that we will have done so.
//
modified = true;
//
// Get the operand that needs to be replaced as well as the operand
// with all of the casts peeled away. Increment the operand index by
// one because a call instruction's first operand is the function to
// call.
//
Value * RealOperand = Check.getCheckedPointer (CI);
Value * PeeledOperand = RealOperand->stripPointerCasts();
//
// Cast the result of the call instruction to match that of the original
// value.
//
BasicBlock::iterator i(CI);
Instruction * CastCI = castTo (CI,
PeeledOperand->getType(),
PeeledOperand->getName(),
++i);
//
// Get dominator information for the function.
//
if ((CI->getParent()->getParent()) != CurrentFunction) {
CurrentFunction = CI->getParent()->getParent();
domTree = &getAnalysis<DominatorTree>(*CurrentFunction);
}
//
// For every use that the call instruction dominates, change the use to
// use the result of the call instruction. We first collect the uses
// that need to be modified before doing the modifications to avoid any
// iterator invalidation errors.
//
std::vector<User *> Uses;
Value::use_iterator UI = PeeledOperand->use_begin();
for (; UI != PeeledOperand->use_end(); ++UI) {
if (Instruction * Use = dyn_cast<Instruction>(*UI))
if ((CI != Use) && (domTree->dominates (CI, Use))) {
Uses.push_back (*UI);
++Changes;
}
}
while (Uses.size()) {
User * Use = Uses.back();
Uses.pop_back();
Use->replaceUsesOfWith (PeeledOperand, CastCI);
}
}
}
return modified;
}
bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
BasicBlock *DefBB = I->getParent();
// If the result of a {s|z}ext and its source are both live out, rewrite all
// other uses of the source with result of extension.
Value *Src = I->getOperand(0);
if (Src->hasOneUse())
return false;
// Only do this xform if truncating is free.
if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
return false;
// Only safe to perform the optimization if the source is also defined in
// this block.
if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
return false;
bool DefIsLiveOut = false;
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
// Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
DefIsLiveOut = true;
break;
}
if (!DefIsLiveOut)
return false;
// Make sure non of the uses are PHI nodes.
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
// Be conservative. We don't want this xform to end up introducing
// reloads just before load / store instructions.
if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
return false;
}
// InsertedTruncs - Only insert one trunc in each block once.
DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
bool MadeChange = false;
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
// Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
// Both src and def are live in this block. Rewrite the use.
Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
if (!InsertedTrunc) {
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
}
// Replace a use of the {s|z}ext source with a use of the result.
TheUse = InsertedTrunc;
++NumExtUses;
MadeChange = true;
}
return MadeChange;
}
void InlineCostAnalyzer::FunctionInfo::countCodeReductionForPointerPair(
const CodeMetrics &Metrics, DenseMap<Value *, unsigned> &PointerArgs,
Value *V, unsigned ArgIdx) {
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI){
Instruction *I = cast<Instruction>(*UI);
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has variable indices, we won't be able to do much with it.
if (!GEP->hasAllConstantIndices())
continue;
// Unless the GEP is in-bounds, some comparisons will be non-constant.
// Fortunately, the real-world cases where this occurs uses in-bounds
// GEPs, and so we restrict the optimization to them here.
if (!GEP->isInBounds())
continue;
// Constant indices just change the constant offset. Add the resulting
// value both to our worklist for this argument, and to the set of
// viable paired values with future arguments.
PointerArgs[GEP] = ArgIdx;
Worklist.push_back(GEP);
continue;
}
// Track pointer through casts. Even when the result is not a pointer, it
// remains a constant relative to constants derived from other constant
// pointers.
if (CastInst *CI = dyn_cast<CastInst>(I)) {
PointerArgs[CI] = ArgIdx;
Worklist.push_back(CI);
continue;
}
// There are two instructions which produce a strict constant value when
// applied to two related pointer values. Ignore everything else.
if (!isa<ICmpInst>(I) && I->getOpcode() != Instruction::Sub)
continue;
assert(I->getNumOperands() == 2);
// Ensure that the two operands are in our set of potentially paired
// pointers (or are derived from them).
Value *OtherArg = I->getOperand(0);
if (OtherArg == V)
OtherArg = I->getOperand(1);
DenseMap<Value *, unsigned>::const_iterator ArgIt
= PointerArgs.find(OtherArg);
if (ArgIt == PointerArgs.end())
continue;
std::pair<unsigned, unsigned> ArgPair(ArgIt->second, ArgIdx);
if (ArgPair.first > ArgPair.second)
std::swap(ArgPair.first, ArgPair.second);
PointerArgPairWeights[ArgPair]
+= countCodeReductionForConstant(Metrics, I);
}
} while (!Worklist.empty());
}
