/// lowerAcrossUnwindEdges - Find all variables which are alive across an unwind
/// edge and spill them.
void SjLjEHPrepare::lowerAcrossUnwindEdges(Function &F,
ArrayRef<InvokeInst *> Invokes) {
// Finally, scan the code looking for instructions with bad live ranges.
for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) {
for (BasicBlock::iterator II = BB->begin(), IIE = BB->end(); II != IIE;
++II) {
// Ignore obvious cases we don't have to handle. In particular, most
// instructions either have no uses or only have a single use inside the
// current block. Ignore them quickly.
Instruction *Inst = II;
if (Inst->use_empty())
continue;
if (Inst->hasOneUse() &&
cast<Instruction>(Inst->user_back())->getParent() == BB &&
!isa<PHINode>(Inst->user_back()))
continue;
// If this is an alloca in the entry block, it's not a real register
// value.
if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
if (isa<ConstantInt>(AI->getArraySize()) && BB == F.begin())
continue;
// Avoid iterator invalidation by copying users to a temporary vector.
SmallVector<Instruction *, 16> Users;
for (User *U : Inst->users()) {
Instruction *UI = cast<Instruction>(U);
if (UI->getParent() != BB || isa<PHINode>(UI))
Users.push_back(UI);
}
// Find all of the blocks that this value is live in.
SmallPtrSet<BasicBlock *, 64> LiveBBs;
LiveBBs.insert(Inst->getParent());
while (!Users.empty()) {
Instruction *U = Users.back();
Users.pop_back();
if (!isa<PHINode>(U)) {
MarkBlocksLiveIn(U->getParent(), LiveBBs);
} else {
// Uses for a PHI node occur in their predecessor block.
PHINode *PN = cast<PHINode>(U);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (PN->getIncomingValue(i) == Inst)
MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
}
}
// Now that we know all of the blocks that this thing is live in, see if
// it includes any of the unwind locations.
bool NeedsSpill = false;
for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
DEBUG(dbgs() << "SJLJ Spill: " << *Inst << " around "
<< UnwindBlock->getName() << "\n");
NeedsSpill = true;
break;
}
}
// If we decided we need a spill, do it.
// FIXME: Spilling this way is overkill, as it forces all uses of
// the value to be reloaded from the stack slot, even those that aren't
// in the unwind blocks. We should be more selective.
if (NeedsSpill) {
DemoteRegToStack(*Inst, true);
++NumSpilled;
}
}
}
// Go through the landing pads and remove any PHIs there.
for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
LandingPadInst *LPI = UnwindBlock->getLandingPadInst();
// Place PHIs into a set to avoid invalidating the iterator.
SmallPtrSet<PHINode *, 8> PHIsToDemote;
for (BasicBlock::iterator PN = UnwindBlock->begin(); isa<PHINode>(PN); ++PN)
PHIsToDemote.insert(cast<PHINode>(PN));
if (PHIsToDemote.empty())
continue;
// Demote the PHIs to the stack.
for (SmallPtrSet<PHINode *, 8>::iterator I = PHIsToDemote.begin(),
E = PHIsToDemote.end();
I != E; ++I)
DemotePHIToStack(*I);
// Move the landingpad instruction back to the top of the landing pad block.
LPI->moveBefore(UnwindBlock->begin());
}
}
/// GetShiftedValue - When CanEvaluateShifted returned true for an expression,
/// this value inserts the new computation that produces the shifted value.
static Value *GetShiftedValue(Value *V, unsigned NumBits, bool isLeftShift,
InstCombiner &IC) {
// We can always evaluate constants shifted.
if (Constant *C = dyn_cast<Constant>(V)) {
if (isLeftShift)
V = IC.Builder->CreateShl(C, NumBits);
else
V = IC.Builder->CreateLShr(C, NumBits);
// If we got a constantexpr back, try to simplify it with TD info.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
V = ConstantFoldConstantExpression(CE, IC.getDataLayout(),
IC.getTargetLibraryInfo());
return V;
}
Instruction *I = cast<Instruction>(V);
IC.Worklist.Add(I);
switch (I->getOpcode()) {
default: llvm_unreachable("Inconsistency with CanEvaluateShifted");
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
// Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
I->setOperand(0, GetShiftedValue(I->getOperand(0), NumBits,isLeftShift,IC));
I->setOperand(1, GetShiftedValue(I->getOperand(1), NumBits,isLeftShift,IC));
return I;
case Instruction::Shl: {
BinaryOperator *BO = cast<BinaryOperator>(I);
unsigned TypeWidth = BO->getType()->getScalarSizeInBits();
// We only accept shifts-by-a-constant in CanEvaluateShifted.
ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));
// We can always fold shl(c1)+shl(c2) -> shl(c1+c2).
if (isLeftShift) {
// If this is oversized composite shift, then unsigned shifts get 0.
unsigned NewShAmt = NumBits+CI->getZExtValue();
if (NewShAmt >= TypeWidth)
return Constant::getNullValue(I->getType());
BO->setOperand(1, ConstantInt::get(BO->getType(), NewShAmt));
BO->setHasNoUnsignedWrap(false);
BO->setHasNoSignedWrap(false);
return I;
}
// We turn shl(c)+lshr(c) -> and(c2) if the input doesn't already have
// zeros.
if (CI->getValue() == NumBits) {
APInt Mask(APInt::getLowBitsSet(TypeWidth, TypeWidth - NumBits));
V = IC.Builder->CreateAnd(BO->getOperand(0),
ConstantInt::get(BO->getContext(), Mask));
if (Instruction *VI = dyn_cast<Instruction>(V)) {
VI->moveBefore(BO);
VI->takeName(BO);
}
return V;
}
// We turn shl(c1)+shr(c2) -> shl(c3)+and(c4), but only when we know that
// the and won't be needed.
assert(CI->getZExtValue() > NumBits);
BO->setOperand(1, ConstantInt::get(BO->getType(),
CI->getZExtValue() - NumBits));
BO->setHasNoUnsignedWrap(false);
BO->setHasNoSignedWrap(false);
return BO;
}
case Instruction::LShr: {
BinaryOperator *BO = cast<BinaryOperator>(I);
unsigned TypeWidth = BO->getType()->getScalarSizeInBits();
// We only accept shifts-by-a-constant in CanEvaluateShifted.
ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));
// We can always fold lshr(c1)+lshr(c2) -> lshr(c1+c2).
if (!isLeftShift) {
// If this is oversized composite shift, then unsigned shifts get 0.
unsigned NewShAmt = NumBits+CI->getZExtValue();
if (NewShAmt >= TypeWidth)
return Constant::getNullValue(BO->getType());
BO->setOperand(1, ConstantInt::get(BO->getType(), NewShAmt));
BO->setIsExact(false);
return I;
}
// We turn lshr(c)+shl(c) -> and(c2) if the input doesn't already have
// zeros.
if (CI->getValue() == NumBits) {
APInt Mask(APInt::getHighBitsSet(TypeWidth, TypeWidth - NumBits));
V = IC.Builder->CreateAnd(I->getOperand(0),
ConstantInt::get(BO->getContext(), Mask));
if (Instruction *VI = dyn_cast<Instruction>(V)) {
VI->moveBefore(I);
VI->takeName(I);
}
return V;
}
// We turn lshr(c1)+shl(c2) -> lshr(c3)+and(c4), but only when we know that
// the and won't be needed.
assert(CI->getZExtValue() > NumBits);
BO->setOperand(1, ConstantInt::get(BO->getType(),
CI->getZExtValue() - NumBits));
BO->setIsExact(false);
return BO;
}
case Instruction::Select:
I->setOperand(1, GetShiftedValue(I->getOperand(1), NumBits,isLeftShift,IC));
I->setOperand(2, GetShiftedValue(I->getOperand(2), NumBits,isLeftShift,IC));
return I;
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// get into trouble with cyclic PHIs here because we only consider
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
PN->setIncomingValue(i, GetShiftedValue(PN->getIncomingValue(i),
NumBits, isLeftShift, IC));
return PN;
}
}
}
/// CanEvaluateShifted - See if we can compute the specified value, but shifted
/// logically to the left or right by some number of bits. This should return
/// true if the expression can be computed for the same cost as the current
/// expression tree. This is used to eliminate extraneous shifting from things
/// like:
/// %C = shl i128 %A, 64
/// %D = shl i128 %B, 96
/// %E = or i128 %C, %D
/// %F = lshr i128 %E, 64
/// where the client will ask if E can be computed shifted right by 64-bits. If
/// this succeeds, the GetShiftedValue function will be called to produce the
/// value.
static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
InstCombiner &IC) {
// We can always evaluate constants shifted.
if (isa<Constant>(V))
return true;
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return false;
// If this is the opposite shift, we can directly reuse the input of the shift
// if the needed bits are already zero in the input. This allows us to reuse
// the value which means that we don't care if the shift has multiple uses.
// TODO: Handle opposite shift by exact value.
ConstantInt *CI = 0;
if ((isLeftShift && match(I, m_LShr(m_Value(), m_ConstantInt(CI)))) ||
(!isLeftShift && match(I, m_Shl(m_Value(), m_ConstantInt(CI))))) {
if (CI->getZExtValue() == NumBits) {
// TODO: Check that the input bits are already zero with MaskedValueIsZero
#if 0
// If this is a truncate of a logical shr, we can truncate it to a smaller
// lshr iff we know that the bits we would otherwise be shifting in are
// already zeros.
uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
uint32_t BitWidth = Ty->getScalarSizeInBits();
if (MaskedValueIsZero(I->getOperand(0),
APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth)) &&
CI->getLimitedValue(BitWidth) < BitWidth) {
return CanEvaluateTruncated(I->getOperand(0), Ty);
}
#endif
}
}
// We can't mutate something that has multiple uses: doing so would
// require duplicating the instruction in general, which isn't profitable.
if (!I->hasOneUse()) return false;
switch (I->getOpcode()) {
default: return false;
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
// Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
return CanEvaluateShifted(I->getOperand(0), NumBits, isLeftShift, IC) &&
CanEvaluateShifted(I->getOperand(1), NumBits, isLeftShift, IC);
case Instruction::Shl: {
// We can often fold the shift into shifts-by-a-constant.
CI = dyn_cast<ConstantInt>(I->getOperand(1));
if (CI == 0) return false;
// We can always fold shl(c1)+shl(c2) -> shl(c1+c2).
if (isLeftShift) return true;
// We can always turn shl(c)+shr(c) -> and(c2).
if (CI->getValue() == NumBits) return true;
unsigned TypeWidth = I->getType()->getScalarSizeInBits();
// We can turn shl(c1)+shr(c2) -> shl(c3)+and(c4), but it isn't
// profitable unless we know the and'd out bits are already zero.
if (CI->getZExtValue() > NumBits) {
unsigned LowBits = TypeWidth - CI->getZExtValue();
if (MaskedValueIsZero(I->getOperand(0),
APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
return true;
}
return false;
}
case Instruction::LShr: {
// We can often fold the shift into shifts-by-a-constant.
CI = dyn_cast<ConstantInt>(I->getOperand(1));
if (CI == 0) return false;
// We can always fold lshr(c1)+lshr(c2) -> lshr(c1+c2).
if (!isLeftShift) return true;
// We can always turn lshr(c)+shl(c) -> and(c2).
if (CI->getValue() == NumBits) return true;
unsigned TypeWidth = I->getType()->getScalarSizeInBits();
// We can always turn lshr(c1)+shl(c2) -> lshr(c3)+and(c4), but it isn't
// profitable unless we know the and'd out bits are already zero.
if (CI->getValue().ult(TypeWidth) && CI->getZExtValue() > NumBits) {
unsigned LowBits = CI->getZExtValue() - NumBits;
if (MaskedValueIsZero(I->getOperand(0),
APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
return true;
}
return false;
}
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
return CanEvaluateShifted(SI->getTrueValue(), NumBits, isLeftShift, IC) &&
CanEvaluateShifted(SI->getFalseValue(), NumBits, isLeftShift, IC);
}
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// get into trouble with cyclic PHIs here because we only consider
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (!CanEvaluateShifted(PN->getIncomingValue(i), NumBits, isLeftShift,IC))
return false;
return true;
}
}
}
// If we have a PHI node with a vector type that has only 2 uses: feed
// itself and be an operand of extractelement at a constant location,
// try to replace the PHI of the vector type with a PHI of a scalar type.
Instruction *InstCombiner::scalarizePHI(ExtractElementInst &EI, PHINode *PN) {
// Verify that the PHI node has exactly 2 uses. Otherwise return NULL.
if (!PN->hasNUses(2))
return nullptr;
// If so, it's known at this point that one operand is PHI and the other is
// an extractelement node. Find the PHI user that is not the extractelement
// node.
auto iu = PN->user_begin();
Instruction *PHIUser = dyn_cast<Instruction>(*iu);
if (PHIUser == cast<Instruction>(&EI))
PHIUser = cast<Instruction>(*(++iu));
// Verify that this PHI user has one use, which is the PHI itself,
// and that it is a binary operation which is cheap to scalarize.
// otherwise return NULL.
if (!PHIUser->hasOneUse() || !(PHIUser->user_back() == PN) ||
!(isa<BinaryOperator>(PHIUser)) || !cheapToScalarize(PHIUser, true))
return nullptr;
// Create a scalar PHI node that will replace the vector PHI node
// just before the current PHI node.
PHINode *scalarPHI = cast<PHINode>(InsertNewInstWith(
PHINode::Create(EI.getType(), PN->getNumIncomingValues(), ""), *PN));
// Scalarize each PHI operand.
for (unsigned i = 0; i < PN->getNumIncomingValues(); i++) {
Value *PHIInVal = PN->getIncomingValue(i);
BasicBlock *inBB = PN->getIncomingBlock(i);
Value *Elt = EI.getIndexOperand();
// If the operand is the PHI induction variable:
if (PHIInVal == PHIUser) {
// Scalarize the binary operation. Its first operand is the
// scalar PHI, and the second operand is extracted from the other
// vector operand.
BinaryOperator *B0 = cast<BinaryOperator>(PHIUser);
unsigned opId = (B0->getOperand(0) == PN) ? 1 : 0;
Value *Op = InsertNewInstWith(
ExtractElementInst::Create(B0->getOperand(opId), Elt,
B0->getOperand(opId)->getName() + ".Elt"),
*B0);
Value *newPHIUser = InsertNewInstWith(
BinaryOperator::Create(B0->getOpcode(), scalarPHI, Op), *B0);
scalarPHI->addIncoming(newPHIUser, inBB);
} else {
// Scalarize PHI input:
Instruction *newEI = ExtractElementInst::Create(PHIInVal, Elt, "");
// Insert the new instruction into the predecessor basic block.
Instruction *pos = dyn_cast<Instruction>(PHIInVal);
BasicBlock::iterator InsertPos;
if (pos && !isa<PHINode>(pos)) {
InsertPos = ++pos->getIterator();
} else {
InsertPos = inBB->getFirstInsertionPt();
}
InsertNewInstWith(newEI, *InsertPos);
scalarPHI->addIncoming(newEI, inBB);
}
}
return replaceInstUsesWith(EI, scalarPHI);
}
void
DebriefDlg::Show()
{
FormWindow::Show();
Game::SetTimeCompression(1);
mission = 0;
campaign = Campaign::GetCampaign();
sim = Sim::GetSim();
if (sim)
ship = sim->GetPlayerShip();
if (campaign)
mission = campaign->GetMission();
if (mission_name) {
if (mission)
mission_name->SetText(mission->Name());
else
mission_name->SetText(Game::GetText("DebriefDlg.mission-name"));
}
if (mission_system) {
mission_system->SetText("");
if (mission) {
StarSystem* sys = mission->GetStarSystem();
if (sys)
mission_system->SetText(sys->Name());
}
}
if (mission_sector) {
mission_sector->SetText("");
if (mission) {
MissionElement* elem = mission->GetElements()[0];
if (elem)
mission_sector->SetText(elem->Region());
}
}
if (mission_time_start) {
if (mission) {
char txt[32];
FormatDayTime(txt, mission->Start());
mission_time_start->SetText(txt);
}
}
if (objectives) {
bool found_objectives = false;
if (sim && sim->GetPlayerElement()) {
Text text;
Element* elem = sim->GetPlayerElement();
for (int i = 0; i < elem->NumObjectives(); i++) {
Instruction* obj = elem->GetObjective(i);
text += Text("* ") + obj->GetDescription() + Text("\n");
found_objectives = true;
}
objectives->SetText(text);
}
if (!found_objectives) {
if (mission)
objectives->SetText(mission->Objective());
else
objectives->SetText(Game::GetText("DebriefDlg.unspecified"));
}
}
if (situation) {
if (mission)
situation->SetText(mission->Situation());
else
situation->SetText(Game::GetText("DebriefDlg.unknown"));
}
if (mission_score) {
mission_score->SetText(Game::GetText("DebriefDlg.no-stats"));
if (ship) {
for (int i = 0; i < ShipStats::NumStats(); i++) {
ShipStats* stats = ShipStats::GetStats(i);
if (stats && !strcmp(ship->Name(), stats->GetName())) {
stats->Summarize();
Player* player = Player::GetCurrentPlayer();
int points = stats->GetPoints() + stats->GetCommandPoints();
if (player && sim)
points = player->GetMissionPoints(stats, sim->StartTime()) + stats->GetCommandPoints();
char score[32];
sprintf_s(score, "%d %s", points, Game::GetText("DebriefDlg.points").data());
mission_score->SetText(score);
break;
}
}
}
}
DrawUnits();
}
/// \brief Assign DWARF discriminators.
///
/// To assign discriminators, we examine the boundaries of every
/// basic block and its successors. Suppose there is a basic block B1
/// with successor B2. The last instruction I1 in B1 and the first
/// instruction I2 in B2 are located at the same file and line number.
/// This situation is illustrated in the following code snippet:
///
/// if (i < 10) x = i;
///
/// entry:
/// br i1 %cmp, label %if.then, label %if.end, !dbg !10
/// if.then:
/// %1 = load i32* %i.addr, align 4, !dbg !10
/// store i32 %1, i32* %x, align 4, !dbg !10
/// br label %if.end, !dbg !10
/// if.end:
/// ret void, !dbg !12
///
/// Notice how the branch instruction in block 'entry' and all the
/// instructions in block 'if.then' have the exact same debug location
/// information (!dbg !10).
///
/// To distinguish instructions in block 'entry' from instructions in
/// block 'if.then', we generate a new lexical block for all the
/// instruction in block 'if.then' that share the same file and line
/// location with the last instruction of block 'entry'.
///
/// This new lexical block will have the same location information as
/// the previous one, but with a new DWARF discriminator value.
///
/// One of the main uses of this discriminator value is in runtime
/// sample profilers. It allows the profiler to distinguish instructions
/// at location !dbg !10 that execute on different basic blocks. This is
/// important because while the predicate 'if (x < 10)' may have been
/// executed millions of times, the assignment 'x = i' may have only
/// executed a handful of times (meaning that the entry->if.then edge is
/// seldom taken).
///
/// If we did not have discriminator information, the profiler would
/// assign the same weight to both blocks 'entry' and 'if.then', which
/// in turn will make it conclude that the entry->if.then edge is very
/// hot.
///
/// To decide where to create new discriminator values, this function
/// traverses the CFG and examines instruction at basic block boundaries.
/// If the last instruction I1 of a block B1 is at the same file and line
/// location as instruction I2 of successor B2, then it creates a new
/// lexical block for I2 and all the instruction in B2 that share the same
/// file and line location as I2. This new lexical block will have a
/// different discriminator number than I1.
bool AddDiscriminators::runOnFunction(Function &F) {
// If the function has debug information, but the user has disabled
// discriminators, do nothing.
// Simlarly, if the function has no debug info, do nothing.
// Finally, if this module is built with dwarf versions earlier than 4,
// do nothing (discriminator support is a DWARF 4 feature).
if (NoDiscriminators ||
!hasDebugInfo(F) ||
F.getParent()->getDwarfVersion() < 4)
return false;
bool Changed = false;
Module *M = F.getParent();
LLVMContext &Ctx = M->getContext();
DIBuilder Builder(*M, /*AllowUnresolved*/ false);
// Traverse all the blocks looking for instructions in different
// blocks that are at the same file:line location.
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
BasicBlock *B = I;
TerminatorInst *Last = B->getTerminator();
DILocation LastDIL = Last->getDebugLoc().get();
if (!LastDIL)
continue;
for (unsigned I = 0; I < Last->getNumSuccessors(); ++I) {
BasicBlock *Succ = Last->getSuccessor(I);
Instruction *First = Succ->getFirstNonPHIOrDbgOrLifetime();
DILocation FirstDIL = First->getDebugLoc().get();
if (!FirstDIL)
continue;
// If the first instruction (First) of Succ is at the same file
// location as B's last instruction (Last), add a new
// discriminator for First's location and all the instructions
// in Succ that share the same location with First.
if (!FirstDIL->canDiscriminate(*LastDIL)) {
// Create a new lexical scope and compute a new discriminator
// number for it.
StringRef Filename = FirstDIL->getFilename();
auto *Scope = FirstDIL->getScope();
auto *File = Builder.createFile(Filename, Scope->getDirectory());
// FIXME: Calculate the discriminator here, based on local information,
// and delete MDLocation::computeNewDiscriminator(). The current
// solution gives different results depending on other modules in the
// same context. All we really need is to discriminate between
// FirstDIL and LastDIL -- a local map would suffice.
unsigned Discriminator = FirstDIL->computeNewDiscriminator();
auto *NewScope =
Builder.createLexicalBlockFile(Scope, File, Discriminator);
auto *NewDIL =
MDLocation::get(Ctx, FirstDIL->getLine(), FirstDIL->getColumn(),
NewScope, FirstDIL->getInlinedAt());
DebugLoc newDebugLoc = NewDIL;
// Attach this new debug location to First and every
// instruction following First that shares the same location.
for (BasicBlock::iterator I1(*First), E1 = Succ->end(); I1 != E1;
++I1) {
if (I1->getDebugLoc().get() != FirstDIL)
break;
I1->setDebugLoc(newDebugLoc);
DEBUG(dbgs() << NewDIL->getFilename() << ":" << NewDIL->getLine()
<< ":" << NewDIL->getColumn() << ":"
<< NewDIL->getDiscriminator() << *I1 << "\n");
}
DEBUG(dbgs() << "\n");
Changed = true;
}
}
}
return Changed;
}
/// The specified block is found to be reachable, clone it and
/// anything that it can reach.
void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
BasicBlock::const_iterator StartingInst,
std::vector<const BasicBlock*> &ToClone){
WeakVH &BBEntry = VMap[BB];
// Have we already cloned this block?
if (BBEntry) return;
// Nope, clone it now.
BasicBlock *NewBB;
BBEntry = NewBB = BasicBlock::Create(BB->getContext());
if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
// It is only legal to clone a function if a block address within that
// function is never referenced outside of the function. Given that, we
// want to map block addresses from the old function to block addresses in
// the clone. (This is different from the generic ValueMapper
// implementation, which generates an invalid blockaddress when
// cloning a function.)
//
// Note that we don't need to fix the mapping for unreachable blocks;
// the default mapping there is safe.
if (BB->hasAddressTaken()) {
Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
const_cast<BasicBlock*>(BB));
VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
}
bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
// Loop over all instructions, and copy them over, DCE'ing as we go. This
// loop doesn't include the terminator.
for (BasicBlock::const_iterator II = StartingInst, IE = --BB->end();
II != IE; ++II) {
Instruction *NewInst = II->clone();
// Eagerly remap operands to the newly cloned instruction, except for PHI
// nodes for which we defer processing until we update the CFG.
if (!isa<PHINode>(NewInst)) {
RemapInstruction(NewInst, VMap,
ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
// If we can simplify this instruction to some other value, simply add
// a mapping to that value rather than inserting a new instruction into
// the basic block.
if (Value *V =
SimplifyInstruction(NewInst, BB->getModule()->getDataLayout())) {
// On the off-chance that this simplifies to an instruction in the old
// function, map it back into the new function.
if (Value *MappedV = VMap.lookup(V))
V = MappedV;
VMap[&*II] = V;
delete NewInst;
continue;
}
}
if (II->hasName())
NewInst->setName(II->getName()+NameSuffix);
VMap[&*II] = NewInst; // Add instruction map to value.
NewBB->getInstList().push_back(NewInst);
hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
if (CodeInfo)
if (auto CS = ImmutableCallSite(&*II))
if (CS.hasOperandBundles())
CodeInfo->OperandBundleCallSites.push_back(NewInst);
if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
if (isa<ConstantInt>(AI->getArraySize()))
hasStaticAllocas = true;
else
hasDynamicAllocas = true;
}
}
// Finally, clone over the terminator.
const TerminatorInst *OldTI = BB->getTerminator();
bool TerminatorDone = false;
if (const BranchInst *BI = dyn_cast<BranchInst>(OldTI)) {
if (BI->isConditional()) {
// If the condition was a known constant in the callee...
ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
// Or is a known constant in the caller...
if (!Cond) {
Value *V = VMap.lookup(BI->getCondition());
Cond = dyn_cast_or_null<ConstantInt>(V);
}
// Constant fold to uncond branch!
if (Cond) {
BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
VMap[OldTI] = BranchInst::Create(Dest, NewBB);
ToClone.push_back(Dest);
TerminatorDone = true;
}
}
} else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
// If switching on a value known constant in the caller.
ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
if (!Cond) { // Or known constant after constant prop in the callee...
Value *V = VMap.lookup(SI->getCondition());
Cond = dyn_cast_or_null<ConstantInt>(V);
}
if (Cond) { // Constant fold to uncond branch!
SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
VMap[OldTI] = BranchInst::Create(Dest, NewBB);
ToClone.push_back(Dest);
TerminatorDone = true;
}
}
if (!TerminatorDone) {
Instruction *NewInst = OldTI->clone();
if (OldTI->hasName())
NewInst->setName(OldTI->getName()+NameSuffix);
NewBB->getInstList().push_back(NewInst);
VMap[OldTI] = NewInst; // Add instruction map to value.
if (CodeInfo)
if (auto CS = ImmutableCallSite(OldTI))
if (CS.hasOperandBundles())
CodeInfo->OperandBundleCallSites.push_back(NewInst);
// Recursively clone any reachable successor blocks.
const TerminatorInst *TI = BB->getTerminator();
for (const BasicBlock *Succ : TI->successors())
ToClone.push_back(Succ);
}
if (CodeInfo) {
CodeInfo->ContainsCalls |= hasCalls;
CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
BB != &BB->getParent()->front();
}
}
void StatsTracker::computeReachableUncovered() {
KModule *km = executor.kmodule;
Module *m = km->module;
static bool init = true;
const InstructionInfoTable &infos = *km->infos;
StatisticManager &sm = *theStatisticManager;
if (init) {
init = false;
// Compute call targets. It would be nice to use alias information
// instead of assuming all indirect calls hit all escaping
// functions, eh?
for (Module::iterator fnIt = m->begin(), fn_ie = m->end();
fnIt != fn_ie; ++fnIt) {
for (Function::iterator bbIt = fnIt->begin(), bb_ie = fnIt->end();
bbIt != bb_ie; ++bbIt) {
for (BasicBlock::iterator it = bbIt->begin(), ie = bbIt->end();
it != ie; ++it) {
if (isa<CallInst>(it) || isa<InvokeInst>(it)) {
CallSite cs(it);
if (isa<InlineAsm>(cs.getCalledValue())) {
// We can never call through here so assume no targets
// (which should be correct anyhow).
callTargets.insert(std::make_pair(it,
std::vector<Function*>()));
} else if (Function *target = getDirectCallTarget(cs)) {
callTargets[it].push_back(target);
} else {
callTargets[it] =
std::vector<Function*>(km->escapingFunctions.begin(),
km->escapingFunctions.end());
}
}
}
}
}
// Compute function callers as reflexion of callTargets.
for (calltargets_ty::iterator it = callTargets.begin(),
ie = callTargets.end(); it != ie; ++it)
for (std::vector<Function*>::iterator fit = it->second.begin(),
fie = it->second.end(); fit != fie; ++fit)
functionCallers[*fit].push_back(it->first);
// Initialize minDistToReturn to shortest paths through
// functions. 0 is unreachable.
std::vector<Instruction *> instructions;
for (Module::iterator fnIt = m->begin(), fn_ie = m->end();
fnIt != fn_ie; ++fnIt) {
if (fnIt->isDeclaration()) {
if (fnIt->doesNotReturn()) {
functionShortestPath[fnIt] = 0;
} else {
functionShortestPath[fnIt] = 1; // whatever
}
} else {
functionShortestPath[fnIt] = 0;
}
// Not sure if I should bother to preorder here. XXX I should.
for (Function::iterator bbIt = fnIt->begin(), bb_ie = fnIt->end();
bbIt != bb_ie; ++bbIt) {
for (BasicBlock::iterator it = bbIt->begin(), ie = bbIt->end();
it != ie; ++it) {
instructions.push_back(it);
unsigned id = infos.getInfo(it).id;
sm.setIndexedValue(stats::minDistToReturn,
id,
isa<ReturnInst>(it)
#if LLVM_VERSION_CODE < LLVM_VERSION(3, 1)
|| isa<UnwindInst>(it)
#endif
);
}
}
}
std::reverse(instructions.begin(), instructions.end());
// I'm so lazy it's not even worklisted.
bool changed;
do {
changed = false;
for (std::vector<Instruction*>::iterator it = instructions.begin(),
ie = instructions.end(); it != ie; ++it) {
Instruction *inst = *it;
unsigned bestThrough = 0;
if (isa<CallInst>(inst) || isa<InvokeInst>(inst)) {
std::vector<Function*> &targets = callTargets[inst];
for (std::vector<Function*>::iterator fnIt = targets.begin(),
ie = targets.end(); fnIt != ie; ++fnIt) {
uint64_t dist = functionShortestPath[*fnIt];
if (dist) {
dist = 1+dist; // count instruction itself
if (bestThrough==0 || dist<bestThrough)
bestThrough = dist;
}
}
} else {
bestThrough = 1;
}
if (bestThrough) {
unsigned id = infos.getInfo(*it).id;
uint64_t best, cur = best = sm.getIndexedValue(stats::minDistToReturn, id);
std::vector<Instruction*> succs = getSuccs(*it);
for (std::vector<Instruction*>::iterator it2 = succs.begin(),
ie = succs.end(); it2 != ie; ++it2) {
uint64_t dist = sm.getIndexedValue(stats::minDistToReturn,
infos.getInfo(*it2).id);
if (dist) {
uint64_t val = bestThrough + dist;
if (best==0 || val<best)
best = val;
}
}
// there's a corner case here when a function only includes a single
// instruction (a ret). in that case, we MUST update
// functionShortestPath, or it will remain 0 (erroneously indicating
// that no return instructions are reachable)
Function *f = inst->getParent()->getParent();
if (best != cur
|| (inst == f->begin()->begin()
&& functionShortestPath[f] != best)) {
sm.setIndexedValue(stats::minDistToReturn, id, best);
changed = true;
// Update shortest path if this is the entry point.
if (inst==f->begin()->begin())
functionShortestPath[f] = best;
}
}
}
} while (changed);
}
// compute minDistToUncovered, 0 is unreachable
std::vector<Instruction *> instructions;
for (Module::iterator fnIt = m->begin(), fn_ie = m->end();
fnIt != fn_ie; ++fnIt) {
// Not sure if I should bother to preorder here.
for (Function::iterator bbIt = fnIt->begin(), bb_ie = fnIt->end();
bbIt != bb_ie; ++bbIt) {
for (BasicBlock::iterator it = bbIt->begin(), ie = bbIt->end();
it != ie; ++it) {
unsigned id = infos.getInfo(it).id;
instructions.push_back(&*it);
sm.setIndexedValue(stats::minDistToUncovered,
id,
sm.getIndexedValue(stats::uncoveredInstructions, id));
}
}
}
std::reverse(instructions.begin(), instructions.end());
// I'm so lazy it's not even worklisted.
bool changed;
do {
changed = false;
for (std::vector<Instruction*>::iterator it = instructions.begin(),
ie = instructions.end(); it != ie; ++it) {
Instruction *inst = *it;
uint64_t best, cur = best = sm.getIndexedValue(stats::minDistToUncovered,
infos.getInfo(inst).id);
unsigned bestThrough = 0;
if (isa<CallInst>(inst) || isa<InvokeInst>(inst)) {
std::vector<Function*> &targets = callTargets[inst];
for (std::vector<Function*>::iterator fnIt = targets.begin(),
ie = targets.end(); fnIt != ie; ++fnIt) {
uint64_t dist = functionShortestPath[*fnIt];
if (dist) {
dist = 1+dist; // count instruction itself
if (bestThrough==0 || dist<bestThrough)
bestThrough = dist;
}
if (!(*fnIt)->isDeclaration()) {
uint64_t calleeDist = sm.getIndexedValue(stats::minDistToUncovered,
infos.getFunctionInfo(*fnIt).id);
if (calleeDist) {
calleeDist = 1+calleeDist; // count instruction itself
if (best==0 || calleeDist<best)
best = calleeDist;
}
}
}
} else {
bestThrough = 1;
}
if (bestThrough) {
std::vector<Instruction*> succs = getSuccs(inst);
for (std::vector<Instruction*>::iterator it2 = succs.begin(),
ie = succs.end(); it2 != ie; ++it2) {
uint64_t dist = sm.getIndexedValue(stats::minDistToUncovered,
infos.getInfo(*it2).id);
if (dist) {
uint64_t val = bestThrough + dist;
if (best==0 || val<best)
best = val;
}
}
}
if (best != cur) {
sm.setIndexedValue(stats::minDistToUncovered,
infos.getInfo(inst).id,
best);
changed = true;
}
}
} while (changed);
for (std::set<ExecutionState*>::iterator it = executor.states.begin(),
ie = executor.states.end(); it != ie; ++it) {
ExecutionState *es = *it;
uint64_t currentFrameMinDist = 0;
#if MULTITHREAD
for (Thread::stack_ty::iterator sfIt = es->stack().begin(),
sf_ie = es->stack().end(); sfIt != sf_ie; ++sfIt) {
Thread::stack_ty::iterator next = sfIt + 1;
KInstIterator kii;
if (next==es->stack().end()) {
kii = es->pc();
#else
for (ExecutionState::stack_ty::iterator sfIt = es->stack.begin(),
sf_ie = es->stack.end(); sfIt != sf_ie; ++sfIt) {
ExecutionState::stack_ty::iterator next = sfIt + 1;
KInstIterator kii;
if (next==es->stack.end()) {
kii = es->pc;
#endif
} else {
kii = next->caller;
++kii;
}
sfIt->minDistToUncoveredOnReturn = currentFrameMinDist;
currentFrameMinDist = computeMinDistToUncovered(kii, currentFrameMinDist);
}
}
}
/// AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) {
SmallPtrSet<Function*, 8> SCCNodes;
// Fill SCCNodes with the elements of the SCC. Used for quickly
// looking up whether a given CallGraphNode is in this SCC.
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
SCCNodes.insert((*I)->getFunction());
// Check if any of the functions in the SCC read or write memory. If they
// write memory then they can't be marked readnone or readonly.
bool ReadsMemory = false;
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
Function *F = (*I)->getFunction();
if (F == 0)
// External node - may write memory. Just give up.
return false;
AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(F);
if (MRB == AliasAnalysis::DoesNotAccessMemory)
// Already perfect!
continue;
// Definitions with weak linkage may be overridden at linktime with
// something that writes memory, so treat them like declarations.
if (F->isDeclaration() || F->mayBeOverridden()) {
if (!AliasAnalysis::onlyReadsMemory(MRB))
// May write memory. Just give up.
return false;
ReadsMemory = true;
continue;
}
// Scan the function body for instructions that may read or write memory.
for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
Instruction *I = &*II;
// Some instructions can be ignored even if they read or write memory.
// Detect these now, skipping to the next instruction if one is found.
CallSite CS(cast<Value>(I));
if (CS) {
// Ignore calls to functions in the same SCC.
if (CS.getCalledFunction() && SCCNodes.count(CS.getCalledFunction()))
continue;
AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(CS);
// If the call doesn't access arbitrary memory, we may be able to
// figure out something.
if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
// If the call does access argument pointees, check each argument.
if (AliasAnalysis::doesAccessArgPointees(MRB))
// Check whether all pointer arguments point to local memory, and
// ignore calls that only access local memory.
for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
CI != CE; ++CI) {
Value *Arg = *CI;
if (Arg->getType()->isPointerTy()) {
AliasAnalysis::Location Loc(Arg,
AliasAnalysis::UnknownSize,
I->getMetadata(LLVMContext::MD_tbaa));
if (!AA->pointsToConstantMemory(Loc, /*OrLocal=*/true)) {
if (MRB & AliasAnalysis::Mod)
// Writes non-local memory. Give up.
return false;
if (MRB & AliasAnalysis::Ref)
// Ok, it reads non-local memory.
ReadsMemory = true;
}
}
}
continue;
}
// The call could access any memory. If that includes writes, give up.
if (MRB & AliasAnalysis::Mod)
return false;
// If it reads, note it.
if (MRB & AliasAnalysis::Ref)
ReadsMemory = true;
continue;
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
// Ignore non-volatile loads from local memory. (Atomic is okay here.)
if (!LI->isVolatile()) {
AliasAnalysis::Location Loc = AA->getLocation(LI);
if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
// Ignore non-volatile stores to local memory. (Atomic is okay here.)
if (!SI->isVolatile()) {
AliasAnalysis::Location Loc = AA->getLocation(SI);
if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
} else if (VAArgInst *VI = dyn_cast<VAArgInst>(I)) {
// Ignore vaargs on local memory.
AliasAnalysis::Location Loc = AA->getLocation(VI);
if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
// Any remaining instructions need to be taken seriously! Check if they
// read or write memory.
if (I->mayWriteToMemory())
// Writes memory. Just give up.
return false;
// If this instruction may read memory, remember that.
ReadsMemory |= I->mayReadFromMemory();
}
}
// Success! Functions in this SCC do not access memory, or only read memory.
// Give them the appropriate attribute.
bool MadeChange = false;
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
Function *F = (*I)->getFunction();
if (F->doesNotAccessMemory())
// Already perfect!
continue;
if (F->onlyReadsMemory() && ReadsMemory)
// No change.
continue;
MadeChange = true;
// Clear out any existing attributes.
AttrBuilder B;
B.addAttribute(Attributes::ReadOnly)
.addAttribute(Attributes::ReadNone);
F->removeAttribute(AttributeSet::FunctionIndex,
Attributes::get(F->getContext(), B));
// Add in the new attribute.
B.clear();
B.addAttribute(ReadsMemory ? Attributes::ReadOnly : Attributes::ReadNone);
F->addAttribute(AttributeSet::FunctionIndex,
Attributes::get(F->getContext(), B));
if (ReadsMemory)
++NumReadOnly;
else
++NumReadNone;
}
return MadeChange;
}
MapVector<Instruction *, uint64_t>
llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
const TargetTransformInfo *TTI) {
// DemandedBits will give us every value's live-out bits. But we want
// to ensure no extra casts would need to be inserted, so every DAG
// of connected values must have the same minimum bitwidth.
EquivalenceClasses<Value *> ECs;
SmallVector<Value *, 16> Worklist;
SmallPtrSet<Value *, 4> Roots;
SmallPtrSet<Value *, 16> Visited;
DenseMap<Value *, uint64_t> DBits;
SmallPtrSet<Instruction *, 4> InstructionSet;
MapVector<Instruction *, uint64_t> MinBWs;
// Determine the roots. We work bottom-up, from truncs or icmps.
bool SeenExtFromIllegalType = false;
for (auto *BB : Blocks)
for (auto &I : *BB) {
InstructionSet.insert(&I);
if (TTI && (isa<ZExtInst>(&I) || isa<SExtInst>(&I)) &&
!TTI->isTypeLegal(I.getOperand(0)->getType()))
SeenExtFromIllegalType = true;
// Only deal with non-vector integers up to 64-bits wide.
if ((isa<TruncInst>(&I) || isa<ICmpInst>(&I)) &&
!I.getType()->isVectorTy() &&
I.getOperand(0)->getType()->getScalarSizeInBits() <= 64) {
// Don't make work for ourselves. If we know the loaded type is legal,
// don't add it to the worklist.
if (TTI && isa<TruncInst>(&I) && TTI->isTypeLegal(I.getType()))
continue;
Worklist.push_back(&I);
Roots.insert(&I);
}
}
// Early exit.
if (Worklist.empty() || (TTI && !SeenExtFromIllegalType))
return MinBWs;
// Now proceed breadth-first, unioning values together.
while (!Worklist.empty()) {
Value *Val = Worklist.pop_back_val();
Value *Leader = ECs.getOrInsertLeaderValue(Val);
if (Visited.count(Val))
continue;
Visited.insert(Val);
// Non-instructions terminate a chain successfully.
if (!isa<Instruction>(Val))
continue;
Instruction *I = cast<Instruction>(Val);
// If we encounter a type that is larger than 64 bits, we can't represent
// it so bail out.
if (DB.getDemandedBits(I).getBitWidth() > 64)
return MapVector<Instruction *, uint64_t>();
uint64_t V = DB.getDemandedBits(I).getZExtValue();
DBits[Leader] |= V;
DBits[I] = V;
// Casts, loads and instructions outside of our range terminate a chain
// successfully.
if (isa<SExtInst>(I) || isa<ZExtInst>(I) || isa<LoadInst>(I) ||
!InstructionSet.count(I))
continue;
// Unsafe casts terminate a chain unsuccessfully. We can't do anything
// useful with bitcasts, ptrtoints or inttoptrs and it'd be unsafe to
// transform anything that relies on them.
if (isa<BitCastInst>(I) || isa<PtrToIntInst>(I) || isa<IntToPtrInst>(I) ||
!I->getType()->isIntegerTy()) {
DBits[Leader] |= ~0ULL;
continue;
}
// We don't modify the types of PHIs. Reductions will already have been
// truncated if possible, and inductions' sizes will have been chosen by
// indvars.
if (isa<PHINode>(I))
continue;
if (DBits[Leader] == ~0ULL)
// All bits demanded, no point continuing.
continue;
for (Value *O : cast<User>(I)->operands()) {
ECs.unionSets(Leader, O);
Worklist.push_back(O);
}
}
// Now we've discovered all values, walk them to see if there are
// any users we didn't see. If there are, we can't optimize that
// chain.
for (auto &I : DBits)
for (auto *U : I.first->users())
if (U->getType()->isIntegerTy() && DBits.count(U) == 0)
DBits[ECs.getOrInsertLeaderValue(I.first)] |= ~0ULL;
for (auto I = ECs.begin(), E = ECs.end(); I != E; ++I) {
uint64_t LeaderDemandedBits = 0;
for (auto MI = ECs.member_begin(I), ME = ECs.member_end(); MI != ME; ++MI)
LeaderDemandedBits |= DBits[*MI];
uint64_t MinBW = (sizeof(LeaderDemandedBits) * 8) -
llvm::countLeadingZeros(LeaderDemandedBits);
// Round up to a power of 2
if (!isPowerOf2_64((uint64_t)MinBW))
MinBW = NextPowerOf2(MinBW);
// We don't modify the types of PHIs. Reductions will already have been
// truncated if possible, and inductions' sizes will have been chosen by
// indvars.
// If we are required to shrink a PHI, abandon this entire equivalence class.
bool Abort = false;
for (auto MI = ECs.member_begin(I), ME = ECs.member_end(); MI != ME; ++MI)
if (isa<PHINode>(*MI) && MinBW < (*MI)->getType()->getScalarSizeInBits()) {
Abort = true;
break;
}
if (Abort)
continue;
for (auto MI = ECs.member_begin(I), ME = ECs.member_end(); MI != ME; ++MI) {
if (!isa<Instruction>(*MI))
continue;
Type *Ty = (*MI)->getType();
if (Roots.count(*MI))
Ty = cast<Instruction>(*MI)->getOperand(0)->getType();
if (MinBW < Ty->getScalarSizeInBits())
MinBWs[cast<Instruction>(*MI)] = MinBW;
}
}
return MinBWs;
}
// Analyze interleaved accesses and collect them into interleaved load and
// store groups.
//
// When generating code for an interleaved load group, we effectively hoist all
// loads in the group to the location of the first load in program order. When
// generating code for an interleaved store group, we sink all stores to the
// location of the last store. This code motion can change the order of load
// and store instructions and may break dependences.
//
// The code generation strategy mentioned above ensures that we won't violate
// any write-after-read (WAR) dependences.
//
// E.g., for the WAR dependence: a = A[i]; // (1)
// A[i] = b; // (2)
//
// The store group of (2) is always inserted at or below (2), and the load
// group of (1) is always inserted at or above (1). Thus, the instructions will
// never be reordered. All other dependences are checked to ensure the
// correctness of the instruction reordering.
//
// The algorithm visits all memory accesses in the loop in bottom-up program
// order. Program order is established by traversing the blocks in the loop in
// reverse postorder when collecting the accesses.
//
// We visit the memory accesses in bottom-up order because it can simplify the
// construction of store groups in the presence of write-after-write (WAW)
// dependences.
//
// E.g., for the WAW dependence: A[i] = a; // (1)
// A[i] = b; // (2)
// A[i + 1] = c; // (3)
//
// We will first create a store group with (3) and (2). (1) can't be added to
// this group because it and (2) are dependent. However, (1) can be grouped
// with other accesses that may precede it in program order. Note that a
// bottom-up order does not imply that WAW dependences should not be checked.
void InterleavedAccessInfo::analyzeInterleaving(
bool EnablePredicatedInterleavedMemAccesses) {
LLVM_DEBUG(dbgs() << "LV: Analyzing interleaved accesses...\n");
const ValueToValueMap &Strides = LAI->getSymbolicStrides();
// Holds all accesses with a constant stride.
MapVector<Instruction *, StrideDescriptor> AccessStrideInfo;
collectConstStrideAccesses(AccessStrideInfo, Strides);
if (AccessStrideInfo.empty())
return;
// Collect the dependences in the loop.
collectDependences();
// Holds all interleaved store groups temporarily.
SmallSetVector<InterleaveGroup *, 4> StoreGroups;
// Holds all interleaved load groups temporarily.
SmallSetVector<InterleaveGroup *, 4> LoadGroups;
// Search in bottom-up program order for pairs of accesses (A and B) that can
// form interleaved load or store groups. In the algorithm below, access A
// precedes access B in program order. We initialize a group for B in the
// outer loop of the algorithm, and then in the inner loop, we attempt to
// insert each A into B's group if:
//
// 1. A and B have the same stride,
// 2. A and B have the same memory object size, and
// 3. A belongs in B's group according to its distance from B.
//
// Special care is taken to ensure group formation will not break any
// dependences.
for (auto BI = AccessStrideInfo.rbegin(), E = AccessStrideInfo.rend();
BI != E; ++BI) {
Instruction *B = BI->first;
StrideDescriptor DesB = BI->second;
// Initialize a group for B if it has an allowable stride. Even if we don't
// create a group for B, we continue with the bottom-up algorithm to ensure
// we don't break any of B's dependences.
InterleaveGroup *Group = nullptr;
if (isStrided(DesB.Stride) &&
(!isPredicated(B->getParent()) || EnablePredicatedInterleavedMemAccesses)) {
Group = getInterleaveGroup(B);
if (!Group) {
LLVM_DEBUG(dbgs() << "LV: Creating an interleave group with:" << *B
<< '\n');
Group = createInterleaveGroup(B, DesB.Stride, DesB.Align);
}
if (B->mayWriteToMemory())
StoreGroups.insert(Group);
else
LoadGroups.insert(Group);
}
for (auto AI = std::next(BI); AI != E; ++AI) {
Instruction *A = AI->first;
StrideDescriptor DesA = AI->second;
// Our code motion strategy implies that we can't have dependences
// between accesses in an interleaved group and other accesses located
// between the first and last member of the group. Note that this also
// means that a group can't have more than one member at a given offset.
// The accesses in a group can have dependences with other accesses, but
// we must ensure we don't extend the boundaries of the group such that
// we encompass those dependent accesses.
//
// For example, assume we have the sequence of accesses shown below in a
// stride-2 loop:
//
// (1, 2) is a group | A[i] = a; // (1)
// | A[i-1] = b; // (2) |
// A[i-3] = c; // (3)
// A[i] = d; // (4) | (2, 4) is not a group
//
// Because accesses (2) and (3) are dependent, we can group (2) with (1)
// but not with (4). If we did, the dependent access (3) would be within
// the boundaries of the (2, 4) group.
if (!canReorderMemAccessesForInterleavedGroups(&*AI, &*BI)) {
// If a dependence exists and A is already in a group, we know that A
// must be a store since A precedes B and WAR dependences are allowed.
// Thus, A would be sunk below B. We release A's group to prevent this
// illegal code motion. A will then be free to form another group with
// instructions that precede it.
if (isInterleaved(A)) {
InterleaveGroup *StoreGroup = getInterleaveGroup(A);
StoreGroups.remove(StoreGroup);
releaseGroup(StoreGroup);
}
// If a dependence exists and A is not already in a group (or it was
// and we just released it), B might be hoisted above A (if B is a
// load) or another store might be sunk below A (if B is a store). In
// either case, we can't add additional instructions to B's group. B
// will only form a group with instructions that it precedes.
break;
}
// At this point, we've checked for illegal code motion. If either A or B
// isn't strided, there's nothing left to do.
if (!isStrided(DesA.Stride) || !isStrided(DesB.Stride))
continue;
// Ignore A if it's already in a group or isn't the same kind of memory
// operation as B.
// Note that mayReadFromMemory() isn't mutually exclusive to
// mayWriteToMemory in the case of atomic loads. We shouldn't see those
// here, canVectorizeMemory() should have returned false - except for the
// case we asked for optimization remarks.
if (isInterleaved(A) ||
(A->mayReadFromMemory() != B->mayReadFromMemory()) ||
(A->mayWriteToMemory() != B->mayWriteToMemory()))
continue;
// Check rules 1 and 2. Ignore A if its stride or size is different from
// that of B.
if (DesA.Stride != DesB.Stride || DesA.Size != DesB.Size)
continue;
// Ignore A if the memory object of A and B don't belong to the same
// address space
if (getLoadStoreAddressSpace(A) != getLoadStoreAddressSpace(B))
continue;
// Calculate the distance from A to B.
const SCEVConstant *DistToB = dyn_cast<SCEVConstant>(
PSE.getSE()->getMinusSCEV(DesA.Scev, DesB.Scev));
if (!DistToB)
continue;
int64_t DistanceToB = DistToB->getAPInt().getSExtValue();
// Check rule 3. Ignore A if its distance to B is not a multiple of the
// size.
if (DistanceToB % static_cast<int64_t>(DesB.Size))
continue;
// All members of a predicated interleave-group must have the same predicate,
// and currently must reside in the same BB.
BasicBlock *BlockA = A->getParent();
BasicBlock *BlockB = B->getParent();
if ((isPredicated(BlockA) || isPredicated(BlockB)) &&
(!EnablePredicatedInterleavedMemAccesses || BlockA != BlockB))
continue;
// The index of A is the index of B plus A's distance to B in multiples
// of the size.
int IndexA =
Group->getIndex(B) + DistanceToB / static_cast<int64_t>(DesB.Size);
// Try to insert A into B's group.
if (Group->insertMember(A, IndexA, DesA.Align)) {
LLVM_DEBUG(dbgs() << "LV: Inserted:" << *A << '\n'
<< " into the interleave group with" << *B
<< '\n');
InterleaveGroupMap[A] = Group;
// Set the first load in program order as the insert position.
if (A->mayReadFromMemory())
Group->setInsertPos(A);
}
} // Iteration over A accesses.
} // Iteration over B accesses.
// Remove interleaved store groups with gaps.
for (InterleaveGroup *Group : StoreGroups)
if (Group->getNumMembers() != Group->getFactor()) {
LLVM_DEBUG(
dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n");
releaseGroup(Group);
}
// Remove interleaved groups with gaps (currently only loads) whose memory
// accesses may wrap around. We have to revisit the getPtrStride analysis,
// this time with ShouldCheckWrap=true, since collectConstStrideAccesses does
// not check wrapping (see documentation there).
// FORNOW we use Assume=false;
// TODO: Change to Assume=true but making sure we don't exceed the threshold
// of runtime SCEV assumptions checks (thereby potentially failing to
// vectorize altogether).
// Additional optional optimizations:
// TODO: If we are peeling the loop and we know that the first pointer doesn't
// wrap then we can deduce that all pointers in the group don't wrap.
// This means that we can forcefully peel the loop in order to only have to
// check the first pointer for no-wrap. When we'll change to use Assume=true
// we'll only need at most one runtime check per interleaved group.
for (InterleaveGroup *Group : LoadGroups) {
// Case 1: A full group. Can Skip the checks; For full groups, if the wide
// load would wrap around the address space we would do a memory access at
// nullptr even without the transformation.
if (Group->getNumMembers() == Group->getFactor())
continue;
// Case 2: If first and last members of the group don't wrap this implies
// that all the pointers in the group don't wrap.
// So we check only group member 0 (which is always guaranteed to exist),
// and group member Factor - 1; If the latter doesn't exist we rely on
// peeling (if it is a non-reveresed accsess -- see Case 3).
Value *FirstMemberPtr = getLoadStorePointerOperand(Group->getMember(0));
if (!getPtrStride(PSE, FirstMemberPtr, TheLoop, Strides, /*Assume=*/false,
/*ShouldCheckWrap=*/true)) {
LLVM_DEBUG(
dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n");
releaseGroup(Group);
continue;
}
Instruction *LastMember = Group->getMember(Group->getFactor() - 1);
if (LastMember) {
Value *LastMemberPtr = getLoadStorePointerOperand(LastMember);
if (!getPtrStride(PSE, LastMemberPtr, TheLoop, Strides, /*Assume=*/false,
/*ShouldCheckWrap=*/true)) {
LLVM_DEBUG(
dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n");
releaseGroup(Group);
}
} else {
// Case 3: A non-reversed interleaved load group with gaps: We need
// to execute at least one scalar epilogue iteration. This will ensure
// we don't speculatively access memory out-of-bounds. We only need
// to look for a member at index factor - 1, since every group must have
// a member at index zero.
if (Group->isReverse()) {
LLVM_DEBUG(
dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n");
releaseGroup(Group);
continue;
}
LLVM_DEBUG(
dbgs() << "LV: Interleaved group requires epilogue iteration.\n");
RequiresScalarEpilogue = true;
}
}
}
bool AlignmentFromAssumptions::processAssumption(CallInst *ACall) {
Value *AAPtr;
const SCEV *AlignSCEV, *OffSCEV;
if (!extractAlignmentInfo(ACall, AAPtr, AlignSCEV, OffSCEV))
return false;
const SCEV *AASCEV = SE->getSCEV(AAPtr);
// Apply the assumption to all other users of the specified pointer.
SmallPtrSet<Instruction *, 32> Visited;
SmallVector<Instruction*, 16> WorkList;
for (User *J : AAPtr->users()) {
if (J == ACall)
continue;
if (Instruction *K = dyn_cast<Instruction>(J))
if (isValidAssumeForContext(ACall, K, DL, DT))
WorkList.push_back(K);
}
while (!WorkList.empty()) {
Instruction *J = WorkList.pop_back_val();
if (LoadInst *LI = dyn_cast<LoadInst>(J)) {
unsigned NewAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
LI->getPointerOperand(), SE);
if (NewAlignment > LI->getAlignment()) {
LI->setAlignment(NewAlignment);
++NumLoadAlignChanged;
}
} else if (StoreInst *SI = dyn_cast<StoreInst>(J)) {
unsigned NewAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
SI->getPointerOperand(), SE);
if (NewAlignment > SI->getAlignment()) {
SI->setAlignment(NewAlignment);
++NumStoreAlignChanged;
}
} else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(J)) {
unsigned NewDestAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
MI->getDest(), SE);
// For memory transfers, we need a common alignment for both the
// source and destination. If we have a new alignment for this
// instruction, but only for one operand, save it. If we reach the
// other operand through another assumption later, then we may
// change the alignment at that point.
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
unsigned NewSrcAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
MTI->getSource(), SE);
DenseMap<MemTransferInst *, unsigned>::iterator DI =
NewDestAlignments.find(MTI);
unsigned AltDestAlignment = (DI == NewDestAlignments.end()) ?
0 : DI->second;
DenseMap<MemTransferInst *, unsigned>::iterator SI =
NewSrcAlignments.find(MTI);
unsigned AltSrcAlignment = (SI == NewSrcAlignments.end()) ?
0 : SI->second;
DEBUG(dbgs() << "\tmem trans: " << NewDestAlignment << " " <<
AltDestAlignment << " " << NewSrcAlignment <<
" " << AltSrcAlignment << "\n");
// Of these four alignments, pick the largest possible...
unsigned NewAlignment = 0;
if (NewDestAlignment <= std::max(NewSrcAlignment, AltSrcAlignment))
NewAlignment = std::max(NewAlignment, NewDestAlignment);
if (AltDestAlignment <= std::max(NewSrcAlignment, AltSrcAlignment))
NewAlignment = std::max(NewAlignment, AltDestAlignment);
if (NewSrcAlignment <= std::max(NewDestAlignment, AltDestAlignment))
NewAlignment = std::max(NewAlignment, NewSrcAlignment);
if (AltSrcAlignment <= std::max(NewDestAlignment, AltDestAlignment))
NewAlignment = std::max(NewAlignment, AltSrcAlignment);
if (NewAlignment > MI->getAlignment()) {
MI->setAlignment(ConstantInt::get(Type::getInt32Ty(
MI->getParent()->getContext()), NewAlignment));
++NumMemIntAlignChanged;
}
NewDestAlignments.insert(std::make_pair(MTI, NewDestAlignment));
NewSrcAlignments.insert(std::make_pair(MTI, NewSrcAlignment));
} else if (NewDestAlignment > MI->getAlignment()) {
assert((!isa<MemIntrinsic>(MI) || isa<MemSetInst>(MI)) &&
"Unknown memory intrinsic");
MI->setAlignment(ConstantInt::get(Type::getInt32Ty(
MI->getParent()->getContext()), NewDestAlignment));
++NumMemIntAlignChanged;
}
}
// Now that we've updated that use of the pointer, look for other uses of
// the pointer to update.
Visited.insert(J);
for (User *UJ : J->users()) {
Instruction *K = cast<Instruction>(UJ);
if (!Visited.count(K) && isValidAssumeForContext(ACall, K, DL, DT))
WorkList.push_back(K);
}
}
return true;
}
virtual bool runOnModule(Module &M) {
LLVMContext &C = M.getContext();
Function *printError_func = (Function*)M.getOrInsertFunction("printErrorMessage", Type::getVoidTy(C), NULL);
BasicBlock* entryBlock = BasicBlock::Create(C, "", printError_func);
IRBuilder<> builder(entryBlock);
Constant *msg = ConstantArray::get(C, "ERROR! Array Index Out of Bounds", true);
Constant *zero_32 = Constant::getNullValue(IntegerType::getInt32Ty(C));
Constant *gep_params[] = {zero_32, zero_32};
GlobalVariable *errorMsg = new GlobalVariable(M, msg->getType(), true, GlobalValue::InternalLinkage, msg, "errorMsg");
Function *puts_func = (Function*)(M.getOrInsertFunction("puts", IntegerType::getInt32Ty(C), PointerType::getUnqual(IntegerType::getInt8Ty(C)), NULL));
Constant *msgptr = ConstantExpr::getGetElementPtr(errorMsg, gep_params);
Value *puts_params[] = {msgptr};
CallInst *puts_call = builder.CreateCall(puts_func, puts_params);
puts_call->setTailCall(false);
Function *exit_func = cast<Function>(M.getOrInsertFunction("exit", IntegerType::getVoidTy(C), Type::getInt32Ty(C),NULL));
Value *exit_val = ConstantInt::get(IntegerType::getInt32Ty(C), 1);
//create exit block. This block prints the error and calls exit system function
BasicBlock* exitBlock = BasicBlock::Create(C, "exitBlock", printError_func);
builder.CreateBr(exitBlock);
builder.SetInsertPoint(exitBlock);
builder.CreateCall(exit_func,exit_val);
builder.CreateBr(exitBlock);
int checksInserted = 0;
for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI)
{
//leave func defs alone
if (!MI->isDeclaration())
{
for (inst_iterator I = inst_begin(*MI), E = inst_end(*MI); I != E; ++I)
{
Instruction *inst = &*I;
if(GetElementPtrInst *gep = dyn_cast<GetElementPtrInst>(inst))
{
if (const ArrayType *ar = dyn_cast<ArrayType>(gep->getPointerOperandType()->getElementType()))
{
//increment checks inserted counter
checksInserted++;
//create split in basic block for function call insertion (branch)
Instruction* next = inst->getNextNode();
BasicBlock* oldBlock = inst->getParent();
BasicBlock* newBlock = SplitBlock(oldBlock, next, this);
//get upper limit and index used
unsigned upperLim = ar->getNumElements();
int index = gep->getNumOperands() - 1;
Value *vIndexUsed = gep->getOperand(index);
Value *vUpperLimit = ConstantInt::get(vIndexUsed->getType(), upperLim);
BasicBlock* checkUpperBlock = BasicBlock::Create(C, "checkUpperBlock", MI, newBlock);
BasicBlock* checkLowerBlock = BasicBlock::Create(C, "checkLowerBlock", MI, checkUpperBlock);
builder.SetInsertPoint(oldBlock);
//remove old terminator
TerminatorInst* term = oldBlock->getTerminator();
term->eraseFromParent();
//insert new one
builder.CreateBr(checkUpperBlock);
//configure uppper bound test
builder.SetInsertPoint(checkUpperBlock);
Value* condUpperInst = builder.CreateICmpSLT(vIndexUsed, vUpperLimit, "checkUpperBounds");
BasicBlock* errorBlock = BasicBlock::Create(C, "errorBlock", MI, newBlock);
builder.CreateCondBr(condUpperInst, checkLowerBlock, errorBlock);
//configure lower bound test
builder.SetInsertPoint(checkLowerBlock);
Value *vLowerLimit = ConstantInt::get(vIndexUsed->getType(), -1);
Value *condLowerInst = builder.CreateICmpSGT(vIndexUsed, vLowerLimit, "checkLowerBounds");
builder.CreateCondBr(condLowerInst, newBlock, errorBlock);
//setup error block. All this block does is call func to print error and exit
builder.SetInsertPoint(errorBlock);
builder.CreateCall(printError_func);
builder.CreateBr(errorBlock);
}
}
}
}
}
errs() << "This pass has inserted " << checksInserted << " checks\n";
return true;
}
/// setupEntryBlockAndCallSites - Setup the entry block by creating and filling
/// the function context and marking the call sites with the appropriate
/// values. These values are used by the DWARF EH emitter.
bool SjLjEHPrepare::setupEntryBlockAndCallSites(Function &F) {
SmallVector<ReturnInst *, 16> Returns;
SmallVector<InvokeInst *, 16> Invokes;
SmallSetVector<LandingPadInst *, 16> LPads;
// Look through the terminators of the basic blocks to find invokes.
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
if (Function *Callee = II->getCalledFunction())
if (Callee->isIntrinsic() &&
Callee->getIntrinsicID() == Intrinsic::donothing) {
// Remove the NOP invoke.
BranchInst::Create(II->getNormalDest(), II);
II->eraseFromParent();
continue;
}
Invokes.push_back(II);
LPads.insert(II->getUnwindDest()->getLandingPadInst());
} else if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
Returns.push_back(RI);
}
if (Invokes.empty())
return false;
NumInvokes += Invokes.size();
lowerIncomingArguments(F);
lowerAcrossUnwindEdges(F, Invokes);
Value *FuncCtx =
setupFunctionContext(F, makeArrayRef(LPads.begin(), LPads.end()));
BasicBlock *EntryBB = F.begin();
IRBuilder<> Builder(EntryBB->getTerminator());
// Get a reference to the jump buffer.
Value *JBufPtr = Builder.CreateConstGEP2_32(FuncCtx, 0, 5, "jbuf_gep");
// Save the frame pointer.
Value *FramePtr = Builder.CreateConstGEP2_32(JBufPtr, 0, 0, "jbuf_fp_gep");
Value *Val = Builder.CreateCall(FrameAddrFn, Builder.getInt32(0), "fp");
Builder.CreateStore(Val, FramePtr, /*isVolatile=*/true);
// Save the stack pointer.
Value *StackPtr = Builder.CreateConstGEP2_32(JBufPtr, 0, 2, "jbuf_sp_gep");
Val = Builder.CreateCall(StackAddrFn, "sp");
Builder.CreateStore(Val, StackPtr, /*isVolatile=*/true);
// Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
Value *SetjmpArg = Builder.CreateBitCast(JBufPtr, Builder.getInt8PtrTy());
Builder.CreateCall(BuiltinSetjmpFn, SetjmpArg);
// Store a pointer to the function context so that the back-end will know
// where to look for it.
Value *FuncCtxArg = Builder.CreateBitCast(FuncCtx, Builder.getInt8PtrTy());
Builder.CreateCall(FuncCtxFn, FuncCtxArg);
// At this point, we are all set up, update the invoke instructions to mark
// their call_site values.
for (unsigned I = 0, E = Invokes.size(); I != E; ++I) {
insertCallSiteStore(Invokes[I], I + 1);
ConstantInt *CallSiteNum =
ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1);
// Record the call site value for the back end so it stays associated with
// the invoke.
CallInst::Create(CallSiteFn, CallSiteNum, "", Invokes[I]);
}
// Mark call instructions that aren't nounwind as no-action (call_site ==
// -1). Skip the entry block, as prior to then, no function context has been
// created for this function and any unexpected exceptions thrown will go
// directly to the caller's context, which is what we want anyway, so no need
// to do anything here.
for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;)
for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
if (CallInst *CI = dyn_cast<CallInst>(I)) {
if (!CI->doesNotThrow())
insertCallSiteStore(CI, -1);
} else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
insertCallSiteStore(RI, -1);
}
// Register the function context and make sure it's known to not throw
CallInst *Register =
CallInst::Create(RegisterFn, FuncCtx, "", EntryBB->getTerminator());
Register->setDoesNotThrow();
// Following any allocas not in the entry block, update the saved SP in the
// jmpbuf to the new value.
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
if (BB == F.begin())
continue;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
if (CallInst *CI = dyn_cast<CallInst>(I)) {
if (CI->getCalledFunction() != StackRestoreFn)
continue;
} else if (!isa<AllocaInst>(I)) {
continue;
}
Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
StackAddr->insertAfter(I);
Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
StoreStackAddr->insertAfter(StackAddr);
}
}
// Finally, for any returns from this function, if this function contains an
// invoke, add a call to unregister the function context.
for (unsigned I = 0, E = Returns.size(); I != E; ++I)
CallInst::Create(UnregisterFn, FuncCtx, "", Returns[I]);
return true;
}
static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
const SimplifyQuery &SQ) {
bool FnChanged = false;
// Visiting in a pre-order depth-first traversal causes us to simplify early
// blocks before querying later blocks (which require us to analyze early
// blocks). Eagerly simplifying shallow blocks means there is strictly less
// work to do for deep blocks. This also means we don't visit unreachable
// blocks.
for (BasicBlock *BB : depth_first(&F.getEntryBlock())) {
bool BBChanged = false;
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
Instruction *II = &*BI++;
switch (II->getOpcode()) {
case Instruction::Select:
BBChanged |= processSelect(cast<SelectInst>(II), LVI);
break;
case Instruction::PHI:
BBChanged |= processPHI(cast<PHINode>(II), LVI, DT, SQ);
break;
case Instruction::ICmp:
case Instruction::FCmp:
BBChanged |= processCmp(cast<CmpInst>(II), LVI);
break;
case Instruction::Load:
case Instruction::Store:
BBChanged |= processMemAccess(II, LVI);
break;
case Instruction::Call:
case Instruction::Invoke:
BBChanged |= processCallSite(CallSite(II), LVI);
break;
case Instruction::SRem:
BBChanged |= processSRem(cast<BinaryOperator>(II), LVI);
break;
case Instruction::SDiv:
BBChanged |= processSDiv(cast<BinaryOperator>(II), LVI);
break;
case Instruction::UDiv:
case Instruction::URem:
BBChanged |= processUDivOrURem(cast<BinaryOperator>(II), LVI);
break;
case Instruction::AShr:
BBChanged |= processAShr(cast<BinaryOperator>(II), LVI);
break;
case Instruction::Add:
BBChanged |= processAdd(cast<BinaryOperator>(II), LVI);
break;
}
}
Instruction *Term = BB->getTerminator();
switch (Term->getOpcode()) {
case Instruction::Switch:
BBChanged |= processSwitch(cast<SwitchInst>(Term), LVI, DT);
break;
case Instruction::Ret: {
auto *RI = cast<ReturnInst>(Term);
// Try to determine the return value if we can. This is mainly here to
// simplify the writing of unit tests, but also helps to enable IPO by
// constant folding the return values of callees.
auto *RetVal = RI->getReturnValue();
if (!RetVal) break; // handle "ret void"
if (isa<Constant>(RetVal)) break; // nothing to do
if (auto *C = getConstantAt(RetVal, RI, LVI)) {
++NumReturns;
RI->replaceUsesOfWith(RetVal, C);
BBChanged = true;
}
}
}
FnChanged |= BBChanged;
}
return FnChanged;
}
Value *llvm::FindAvailablePtrLoadStore(Value *Ptr, Type *AccessTy,
bool AtLeastAtomic, BasicBlock *ScanBB,
BasicBlock::iterator &ScanFrom,
unsigned MaxInstsToScan,
AliasAnalysis *AA, bool *IsLoadCSE,
unsigned *NumScanedInst) {
if (MaxInstsToScan == 0)
MaxInstsToScan = ~0U;
const DataLayout &DL = ScanBB->getModule()->getDataLayout();
// Try to get the store size for the type.
auto AccessSize = LocationSize::precise(DL.getTypeStoreSize(AccessTy));
Value *StrippedPtr = Ptr->stripPointerCasts();
while (ScanFrom != ScanBB->begin()) {
// We must ignore debug info directives when counting (otherwise they
// would affect codegen).
Instruction *Inst = &*--ScanFrom;
if (isa<DbgInfoIntrinsic>(Inst))
continue;
// Restore ScanFrom to expected value in case next test succeeds
ScanFrom++;
if (NumScanedInst)
++(*NumScanedInst);
// Don't scan huge blocks.
if (MaxInstsToScan-- == 0)
return nullptr;
--ScanFrom;
// If this is a load of Ptr, the loaded value is available.
// (This is true even if the load is volatile or atomic, although
// those cases are unlikely.)
if (LoadInst *LI = dyn_cast<LoadInst>(Inst))
if (AreEquivalentAddressValues(
LI->getPointerOperand()->stripPointerCasts(), StrippedPtr) &&
CastInst::isBitOrNoopPointerCastable(LI->getType(), AccessTy, DL)) {
// We can value forward from an atomic to a non-atomic, but not the
// other way around.
if (LI->isAtomic() < AtLeastAtomic)
return nullptr;
if (IsLoadCSE)
*IsLoadCSE = true;
return LI;
}
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
Value *StorePtr = SI->getPointerOperand()->stripPointerCasts();
// If this is a store through Ptr, the value is available!
// (This is true even if the store is volatile or atomic, although
// those cases are unlikely.)
if (AreEquivalentAddressValues(StorePtr, StrippedPtr) &&
CastInst::isBitOrNoopPointerCastable(SI->getValueOperand()->getType(),
AccessTy, DL)) {
// We can value forward from an atomic to a non-atomic, but not the
// other way around.
if (SI->isAtomic() < AtLeastAtomic)
return nullptr;
if (IsLoadCSE)
*IsLoadCSE = false;
return SI->getOperand(0);
}
// If both StrippedPtr and StorePtr reach all the way to an alloca or
// global and they are different, ignore the store. This is a trivial form
// of alias analysis that is important for reg2mem'd code.
if ((isa<AllocaInst>(StrippedPtr) || isa<GlobalVariable>(StrippedPtr)) &&
(isa<AllocaInst>(StorePtr) || isa<GlobalVariable>(StorePtr)) &&
StrippedPtr != StorePtr)
continue;
// If we have alias analysis and it says the store won't modify the loaded
// value, ignore the store.
if (AA && !isModSet(AA->getModRefInfo(SI, StrippedPtr, AccessSize)))
continue;
// Otherwise the store that may or may not alias the pointer, bail out.
++ScanFrom;
return nullptr;
}
// If this is some other instruction that may clobber Ptr, bail out.
if (Inst->mayWriteToMemory()) {
// If alias analysis claims that it really won't modify the load,
// ignore it.
if (AA && !isModSet(AA->getModRefInfo(Inst, StrippedPtr, AccessSize)))
continue;
// May modify the pointer, bail out.
++ScanFrom;
return nullptr;
}
}
// Got to the start of the block, we didn't find it, but are done for this
// block.
return nullptr;
}
/// tryMergingIntoMemset - When scanning forward over instructions, we look for
/// some other patterns to fold away. In particular, this looks for stores to
/// neighboring locations of memory. If it sees enough consecutive ones, it
/// attempts to merge them together into a memcpy/memset.
Instruction *MemCpyOpt::tryMergingIntoMemset(Instruction *StartInst,
Value *StartPtr, Value *ByteVal) {
if (TD == 0) return 0;
// Okay, so we now have a single store that can be splatable. Scan to find
// all subsequent stores of the same value to offset from the same pointer.
// Join these together into ranges, so we can decide whether contiguous blocks
// are stored.
MemsetRanges Ranges(*TD);
BasicBlock::iterator BI = StartInst;
for (++BI; !isa<TerminatorInst>(BI); ++BI) {
if (!isa<StoreInst>(BI) && !isa<MemSetInst>(BI)) {
// If the instruction is readnone, ignore it, otherwise bail out. We
// don't even allow readonly here because we don't want something like:
// A[1] = 2; strlen(A); A[2] = 2; -> memcpy(A, ...); strlen(A).
if (BI->mayWriteToMemory() || BI->mayReadFromMemory())
break;
continue;
}
if (StoreInst *NextStore = dyn_cast<StoreInst>(BI)) {
// If this is a store, see if we can merge it in.
if (!NextStore->isSimple()) break;
// Check to see if this stored value is of the same byte-splattable value.
if (ByteVal != isBytewiseValue(NextStore->getOperand(0)))
break;
// Check to see if this store is to a constant offset from the start ptr.
int64_t Offset;
if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(),
Offset, *TD))
break;
Ranges.addStore(Offset, NextStore);
} else {
MemSetInst *MSI = cast<MemSetInst>(BI);
if (MSI->isVolatile() || ByteVal != MSI->getValue() ||
!isa<ConstantInt>(MSI->getLength()))
break;
// Check to see if this store is to a constant offset from the start ptr.
int64_t Offset;
if (!IsPointerOffset(StartPtr, MSI->getDest(), Offset, *TD))
break;
Ranges.addMemSet(Offset, MSI);
}
}
// If we have no ranges, then we just had a single store with nothing that
// could be merged in. This is a very common case of course.
if (Ranges.empty())
return 0;
// If we had at least one store that could be merged in, add the starting
// store as well. We try to avoid this unless there is at least something
// interesting as a small compile-time optimization.
Ranges.addInst(0, StartInst);
// If we create any memsets, we put it right before the first instruction that
// isn't part of the memset block. This ensure that the memset is dominated
// by any addressing instruction needed by the start of the block.
IRBuilder<> Builder(BI);
// Now that we have full information about ranges, loop over the ranges and
// emit memset's for anything big enough to be worthwhile.
Instruction *AMemSet = 0;
for (MemsetRanges::const_iterator I = Ranges.begin(), E = Ranges.end();
I != E; ++I) {
const MemsetRange &Range = *I;
if (Range.TheStores.size() == 1) continue;
// If it is profitable to lower this range to memset, do so now.
if (!Range.isProfitableToUseMemset(*TD))
continue;
// Otherwise, we do want to transform this! Create a new memset.
// Get the starting pointer of the block.
StartPtr = Range.StartPtr;
// Determine alignment
unsigned Alignment = Range.Alignment;
if (Alignment == 0) {
Type *EltType =
cast<PointerType>(StartPtr->getType())->getElementType();
Alignment = TD->getABITypeAlignment(EltType);
}
AMemSet =
Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start, Alignment);
DEBUG(dbgs() << "Replace stores:\n";
for (unsigned i = 0, e = Range.TheStores.size(); i != e; ++i)
dbgs() << *Range.TheStores[i] << '\n';
dbgs() << "With: " << *AMemSet << '\n');
if (!Range.TheStores.empty())
AMemSet->setDebugLoc(Range.TheStores[0]->getDebugLoc());
// Zap all the stores.
for (SmallVector<Instruction*, 16>::const_iterator
SI = Range.TheStores.begin(),
SE = Range.TheStores.end(); SI != SE; ++SI) {
MD->removeInstruction(*SI);
(*SI)->eraseFromParent();
}
++NumMemSetInfer;
}
return AMemSet;
}
// Sinks \p I from the loop \p L's preheader to its uses. Returns true if
// sinking is successful.
// \p LoopBlockNumber is used to sort the insertion blocks to ensure
// determinism.
static bool sinkInstruction(Loop &L, Instruction &I,
const SmallVectorImpl<BasicBlock *> &ColdLoopBBs,
const SmallDenseMap<BasicBlock *, int, 16> &LoopBlockNumber,
LoopInfo &LI, DominatorTree &DT,
BlockFrequencyInfo &BFI) {
// Compute the set of blocks in loop L which contain a use of I.
SmallPtrSet<BasicBlock *, 2> BBs;
for (auto &U : I.uses()) {
Instruction *UI = cast<Instruction>(U.getUser());
// We cannot sink I to PHI-uses.
if (dyn_cast<PHINode>(UI))
return false;
// We cannot sink I if it has uses outside of the loop.
if (!L.contains(LI.getLoopFor(UI->getParent())))
return false;
BBs.insert(UI->getParent());
}
// findBBsToSinkInto is O(BBs.size() * ColdLoopBBs.size()). We cap the max
// BBs.size() to avoid expensive computation.
// FIXME: Handle code size growth for min_size and opt_size.
if (BBs.size() > MaxNumberOfUseBBsForSinking)
return false;
// Find the set of BBs that we should insert a copy of I.
SmallPtrSet<BasicBlock *, 2> BBsToSinkInto =
findBBsToSinkInto(L, BBs, ColdLoopBBs, DT, BFI);
if (BBsToSinkInto.empty())
return false;
// Copy the final BBs into a vector and sort them using the total ordering
// of the loop block numbers as iterating the set doesn't give a useful
// order. No need to stable sort as the block numbers are a total ordering.
SmallVector<BasicBlock *, 2> SortedBBsToSinkInto;
SortedBBsToSinkInto.insert(SortedBBsToSinkInto.begin(), BBsToSinkInto.begin(),
BBsToSinkInto.end());
llvm::sort(SortedBBsToSinkInto.begin(), SortedBBsToSinkInto.end(),
[&](BasicBlock *A, BasicBlock *B) {
return LoopBlockNumber.find(A)->second <
LoopBlockNumber.find(B)->second;
});
BasicBlock *MoveBB = *SortedBBsToSinkInto.begin();
// FIXME: Optimize the efficiency for cloned value replacement. The current
// implementation is O(SortedBBsToSinkInto.size() * I.num_uses()).
for (BasicBlock *N : makeArrayRef(SortedBBsToSinkInto).drop_front(1)) {
assert(LoopBlockNumber.find(N)->second >
LoopBlockNumber.find(MoveBB)->second &&
"BBs not sorted!");
// Clone I and replace its uses.
Instruction *IC = I.clone();
IC->setName(I.getName());
IC->insertBefore(&*N->getFirstInsertionPt());
// Replaces uses of I with IC in N
for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE;) {
Use &U = *UI++;
auto *I = cast<Instruction>(U.getUser());
if (I->getParent() == N)
U.set(IC);
}
// Replaces uses of I with IC in blocks dominated by N
replaceDominatedUsesWith(&I, IC, DT, N);
LLVM_DEBUG(dbgs() << "Sinking a clone of " << I << " To: " << N->getName()
<< '\n');
NumLoopSunkCloned++;
}
LLVM_DEBUG(dbgs() << "Sinking " << I << " To: " << MoveBB->getName() << '\n');
NumLoopSunk++;
I.moveBefore(&*MoveBB->getFirstInsertionPt());
return true;
}
void WorklessInstrument::CloneInnerLoop(Loop * pLoop, vector<BasicBlock *> & vecAdd, ValueToValueMapTy & VMap, set<BasicBlock *> & setCloned)
{
Function * pFunction = pLoop->getHeader()->getParent();
BasicBlock * pPreHeader = vecAdd[0];
SmallVector<BasicBlock *, 4> ExitBlocks;
pLoop->getExitBlocks(ExitBlocks);
set<BasicBlock *> setExitBlocks;
for(unsigned long i = 0; i < ExitBlocks.size(); i++)
{
setExitBlocks.insert(ExitBlocks[i]);
}
for(unsigned long i = 0; i < ExitBlocks.size(); i++ )
{
VMap[ExitBlocks[i]] = ExitBlocks[i];
}
vector<BasicBlock *> ToClone;
vector<BasicBlock *> BeenCloned;
//clone loop
ToClone.push_back(pLoop->getHeader());
while(ToClone.size()>0)
{
BasicBlock * pCurrent = ToClone.back();
ToClone.pop_back();
WeakVH & BBEntry = VMap[pCurrent];
if (BBEntry)
{
continue;
}
BasicBlock * NewBB;
BBEntry = NewBB = BasicBlock::Create(pCurrent->getContext(), "", pFunction);
if(pCurrent->hasName())
{
NewBB->setName(pCurrent->getName() + ".CPI");
}
if(pCurrent->hasAddressTaken())
{
errs() << "hasAddressTaken branch\n" ;
exit(0);
}
for(BasicBlock::const_iterator II = pCurrent->begin(); II != pCurrent->end(); ++II )
{
Instruction * NewInst = II->clone();
if(II->hasName())
{
NewInst->setName(II->getName() + ".CPI");
}
VMap[II] = NewInst;
NewBB->getInstList().push_back(NewInst);
}
const TerminatorInst *TI = pCurrent->getTerminator();
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
{
ToClone.push_back(TI->getSuccessor(i));
}
setCloned.insert(NewBB);
BeenCloned.push_back(NewBB);
}
//remap value used inside loop
vector<BasicBlock *>::iterator itVecBegin = BeenCloned.begin();
vector<BasicBlock *>::iterator itVecEnd = BeenCloned.end();
for(; itVecBegin != itVecEnd; itVecBegin ++)
{
for(BasicBlock::iterator II = (*itVecBegin)->begin(); II != (*itVecBegin)->end(); II ++ )
{
//II->dump();
RemapInstruction(II, VMap);
}
}
//add to the else if body
BasicBlock * pElseBody = vecAdd[1];
BasicBlock * pClonedHeader = cast<BasicBlock>(VMap[pLoop->getHeader()]);
BranchInst::Create(pClonedHeader, pElseBody);
//errs() << pPreHeader->getName() << "\n";
for(BasicBlock::iterator II = pClonedHeader->begin(); II != pClonedHeader->end(); II ++ )
{
if(PHINode * pPHI = dyn_cast<PHINode>(II))
{
vector<int> vecToRemoved;
for (unsigned i = 0, e = pPHI->getNumIncomingValues(); i != e; ++i)
{
if(pPHI->getIncomingBlock(i) == pPreHeader)
{
pPHI->setIncomingBlock(i, pElseBody);
}
}
}
}
set<BasicBlock *> setProcessedBlock;
for(unsigned long i = 0; i < ExitBlocks.size(); i++ )
{
if(setProcessedBlock.find(ExitBlocks[i]) != setProcessedBlock.end() )
{
continue;
}
else
{
setProcessedBlock.insert(ExitBlocks[i]);
}
for(BasicBlock::iterator II = ExitBlocks[i]->begin(); II != ExitBlocks[i]->end(); II ++ )
{
if(PHINode * pPHI = dyn_cast<PHINode>(II))
{
unsigned numIncomming = pPHI->getNumIncomingValues();
for(unsigned i = 0; i<numIncomming; i++)
{
BasicBlock * incommingBlock = pPHI->getIncomingBlock(i);
if(VMap.find(incommingBlock) != VMap.end() )
{
Value * incommingValue = pPHI->getIncomingValue(i);
if(VMap.find(incommingValue) != VMap.end() )
{
incommingValue = VMap[incommingValue];
}
pPHI->addIncoming(incommingValue, cast<BasicBlock>(VMap[incommingBlock]));
}
}
}
}
}
}
Value* ModuloSchedulerDriverPass::copyLoopBodyToHeader(Instruction* inst,
Instruction* induction, BasicBlock* header, int offset){
// Holds the body of the interesting loop
BasicBlock *body = inst->getParent();
assert(header && "Header is null");
assert(header->getTerminator() && "Header has no terminator");
// Maps the old instructions to the new Instructions
DenseMap<const Value *, Value *> ValueMap;
// Do the actual clone
stringstream iname;
iname<<"___"<<offset<<"___";
BasicBlock* newBB = CloneBasicBlock(body, ValueMap, iname.str().c_str());
// Fixing the dependencies for each of the instructions in the cloned BB
// They now depend on themselves rather on the old cloned BB.
for (BasicBlock::iterator it = newBB->begin(); it != newBB->end(); ++it) {
for (Instruction::op_iterator ops = (it)->op_begin(); ops != (it)->op_end(); ++ops) {
if (ValueMap.end() != ValueMap.find(*ops)) {
//*ops = ValueMap[*ops];
it->replaceUsesOfWith(*ops, ValueMap[*ops]);
}
}
}
// Fixing the PHI nodes since they are no longer needed
for (BasicBlock::iterator it = newBB->begin(); it != newBB->end(); ++it) {
if (PHINode *phi = dyn_cast<PHINode>(it)) {
// Taking the preheader entryfrom the PHI node
Value* prevalue = phi->getIncomingValue(phi->getBasicBlockIndex(header));
assert(prevalue && "no prevalue. Don't know what to do");
// If we are handling a PHI node which is the induction index ? A[PHI(i,0)] ?
// If so, turn it into A[i + offset]
if (ValueMap[induction] == phi) {
Instruction *add = subscripts::incrementValue(prevalue, offset);
//add->insertBefore(phi); This is the same as next line (compiles on LLVM2.1)
phi->getParent()->getInstList().insert(phi, add);
phi->replaceAllUsesWith(add);
} else {
// eliminating the PHI node all together
// This is just a regular variable or constant. No need to increment
// the index.
phi->replaceAllUsesWith(prevalue);
}
}
}
// Move all non PHI and non terminator instructions into the header.
while (!newBB->getFirstNonPHI()->isTerminator()) {
Instruction* inst = newBB->getFirstNonPHI();
if (dyn_cast<StoreInst>(inst)) {
inst->eraseFromParent();
} else {
inst->moveBefore(header->getTerminator());
}
}
newBB->dropAllReferences();
return ValueMap[inst];
}
/// Return true if we can evaluate the specified expression tree if the vector
/// elements were shuffled in a different order.
static bool CanEvaluateShuffled(Value *V, ArrayRef<int> Mask,
unsigned Depth = 5) {
// We can always reorder the elements of a constant.
if (isa<Constant>(V))
return true;
// We won't reorder vector arguments. No IPO here.
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return false;
// Two users may expect different orders of the elements. Don't try it.
if (!I->hasOneUse())
return false;
if (Depth == 0) return false;
switch (I->getOpcode()) {
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::ICmp:
case Instruction::FCmp:
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::GetElementPtr: {
for (Value *Operand : I->operands()) {
if (!CanEvaluateShuffled(Operand, Mask, Depth-1))
return false;
}
return true;
}
case Instruction::InsertElement: {
ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(2));
if (!CI) return false;
int ElementNumber = CI->getLimitedValue();
// Verify that 'CI' does not occur twice in Mask. A single 'insertelement'
// can't put an element into multiple indices.
bool SeenOnce = false;
for (int i = 0, e = Mask.size(); i != e; ++i) {
if (Mask[i] == ElementNumber) {
if (SeenOnce)
return false;
SeenOnce = true;
}
}
return CanEvaluateShuffled(I->getOperand(0), Mask, Depth-1);
}
}
return false;
}
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<DominatorTree>();
PA.setAA(&getAnalysis<AliasAnalysis>());
// 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() << "ObjCARCContract: Visiting: " << *Inst << "\n");
// Only these library routines return their argument. In particular,
// objc_retainBlock does not necessarily return its argument.
InstructionClass Class = GetBasicInstructionClass(Inst);
switch (Class) {
case IC_FusedRetainAutorelease:
case IC_FusedRetainAutoreleaseRV:
break;
case IC_Autorelease:
case IC_AutoreleaseRV:
if (ContractAutorelease(F, Inst, Class, DependingInstructions, Visited))
continue;
break;
case IC_Retain:
// Attempt to convert retains to retainrvs if they are next to function
// calls.
if (!OptimizeRetainCall(F, Inst))
break;
// If we succeed in our optimization, fall through.
// FALLTHROUGH
case IC_RetainRV: {
// If we're compiling for a target which needs a special inline-asm
// marker to do the retainAutoreleasedReturnValue optimization,
// insert it now.
if (!RetainRVMarker)
break;
BasicBlock::iterator BBI = Inst;
BasicBlock *InstParent = Inst->getParent();
// Step up to see if the call immediately precedes the RetainRV call.
// If it's an invoke, we have to cross a block boundary. And we have
// to carefully dodge no-op instructions.
do {
if (&*BBI == InstParent->begin()) {
BasicBlock *Pred = InstParent->getSinglePredecessor();
if (!Pred)
goto decline_rv_optimization;
BBI = Pred->getTerminator();
break;
}
--BBI;
} while (IsNoopInstruction(BBI));
if (&*BBI == GetObjCArg(Inst)) {
DEBUG(dbgs() << "ObjCARCContract: Adding inline asm marker for "
"retainAutoreleasedReturnValue optimization.\n");
Changed = true;
InlineAsm *IA =
InlineAsm::get(FunctionType::get(Type::getVoidTy(Inst->getContext()),
/*isVarArg=*/false),
RetainRVMarker->getString(),
/*Constraints=*/"", /*hasSideEffects=*/true);
CallInst::Create(IA, "", Inst);
}
decline_rv_optimization:
break;
}
case IC_InitWeak: {
// objc_initWeak(p, null) => *p = null
CallInst *CI = cast<CallInst>(Inst);
if (IsNullOrUndef(CI->getArgOperand(1))) {
Value *Null =
ConstantPointerNull::get(cast<PointerType>(CI->getType()));
Changed = true;
new StoreInst(Null, CI->getArgOperand(0), CI);
DEBUG(dbgs() << "OBJCARCContract: Old = " << *CI << "\n"
<< " New = " << *Null << "\n");
CI->replaceAllUsesWith(Null);
CI->eraseFromParent();
}
continue;
}
case IC_Release:
ContractRelease(Inst, I);
continue;
case IC_User:
// Be conservative if the function has any alloca instructions.
// Technically we only care about escaping alloca instructions,
// but this is sufficient to handle some interesting cases.
if (isa<AllocaInst>(Inst))
TailOkForStoreStrongs = false;
continue;
case IC_IntrinsicUser:
// Remove calls to @clang.arc.use(...).
Inst->eraseFromParent();
continue;
default:
continue;
}
DEBUG(dbgs() << "ObjCARCContract: Finished List.\n\n");
// Don't use GetObjCArg because we don't want to look through bitcasts
// and such; to do the replacement, the argument must have type i8*.
const Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
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::const_use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
UI != UE; ) {
Use &U = UI.getUse();
unsigned OperandNo = UI.getOperandNo();
++UI; // Increment UI now, because we may unlink its element.
// 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 GetObjCArg.
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 (&PHI->getOperandUse(
PHINode::getOperandNumForIncomingValue(i)) ==
&UI.getUse())
++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 (SmallPtrSet<CallInst *, 8>::iterator I = StoreStrongCalls.begin(),
E = StoreStrongCalls.end(); I != E; ++I)
(*I)->setTailCall();
StoreStrongCalls.clear();
return Changed;
}
Value *
InstCombiner::EvaluateInDifferentElementOrder(Value *V, ArrayRef<int> Mask) {
// Mask.size() does not need to be equal to the number of vector elements.
assert(V->getType()->isVectorTy() && "can't reorder non-vector elements");
if (isa<UndefValue>(V)) {
return UndefValue::get(VectorType::get(V->getType()->getScalarType(),
Mask.size()));
}
if (isa<ConstantAggregateZero>(V)) {
return ConstantAggregateZero::get(
VectorType::get(V->getType()->getScalarType(),
Mask.size()));
}
if (Constant *C = dyn_cast<Constant>(V)) {
SmallVector<Constant *, 16> MaskValues;
for (int i = 0, e = Mask.size(); i != e; ++i) {
if (Mask[i] == -1)
MaskValues.push_back(UndefValue::get(Builder->getInt32Ty()));
else
MaskValues.push_back(Builder->getInt32(Mask[i]));
}
return ConstantExpr::getShuffleVector(C, UndefValue::get(C->getType()),
ConstantVector::get(MaskValues));
}
Instruction *I = cast<Instruction>(V);
switch (I->getOpcode()) {
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::ICmp:
case Instruction::FCmp:
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::Select:
case Instruction::GetElementPtr: {
SmallVector<Value*, 8> NewOps;
bool NeedsRebuild = (Mask.size() != I->getType()->getVectorNumElements());
for (int i = 0, e = I->getNumOperands(); i != e; ++i) {
Value *V = EvaluateInDifferentElementOrder(I->getOperand(i), Mask);
NewOps.push_back(V);
NeedsRebuild |= (V != I->getOperand(i));
}
if (NeedsRebuild) {
return buildNew(I, NewOps);
}
return I;
}
case Instruction::InsertElement: {
int Element = cast<ConstantInt>(I->getOperand(2))->getLimitedValue();
// The insertelement was inserting at Element. Figure out which element
// that becomes after shuffling. The answer is guaranteed to be unique
// by CanEvaluateShuffled.
bool Found = false;
int Index = 0;
for (int e = Mask.size(); Index != e; ++Index) {
if (Mask[Index] == Element) {
Found = true;
break;
}
}
// If element is not in Mask, no need to handle the operand 1 (element to
// be inserted). Just evaluate values in operand 0 according to Mask.
if (!Found)
return EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
Value *V = EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
return InsertElementInst::Create(V, I->getOperand(1),
Builder->getInt32(Index), "", I);
}
}
llvm_unreachable("failed to reorder elements of vector instruction!");
}
// Add the remainder of the reduction-variable chain to the instruction vector
// (the initial PHINode has already been added). If successful, the object is
// marked as valid.
void LoopReroll::SimpleLoopReduction::add(Loop *L) {
assert(!Valid && "Cannot add to an already-valid chain");
// The reduction variable must be a chain of single-use instructions
// (including the PHI), except for the last value (which is used by the PHI
// and also outside the loop).
Instruction *C = Instructions.front();
do {
C = cast<Instruction>(*C->use_begin());
if (C->hasOneUse()) {
if (!C->isBinaryOp())
return;
if (!(isa<PHINode>(Instructions.back()) ||
C->isSameOperationAs(Instructions.back())))
return;
Instructions.push_back(C);
}
} while (C->hasOneUse());
if (Instructions.size() < 2 ||
!C->isSameOperationAs(Instructions.back()) ||
C->use_begin() == C->use_end())
return;
// C is now the (potential) last instruction in the reduction chain.
for (Value::use_iterator UI = C->use_begin(), UIE = C->use_end();
UI != UIE; ++UI) {
// The only in-loop user can be the initial PHI.
if (L->contains(cast<Instruction>(*UI)))
if (cast<Instruction>(*UI ) != Instructions.front())
return;
}
Instructions.push_back(C);
Valid = true;
}
bool PPCLoopDataPrefetch::runOnLoop(Loop *L) {
bool MadeChange = false;
// Only prefetch in the inner-most loop
if (!L->empty())
return MadeChange;
SmallPtrSet<const Value *, 32> EphValues;
CodeMetrics::collectEphemeralValues(L, AC, EphValues);
// Calculate the number of iterations ahead to prefetch
CodeMetrics Metrics;
for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
I != IE; ++I) {
// If the loop already has prefetches, then assume that the user knows
// what he or she is doing and don't add any more.
for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end();
J != JE; ++J)
if (CallInst *CI = dyn_cast<CallInst>(J))
if (Function *F = CI->getCalledFunction())
if (F->getIntrinsicID() == Intrinsic::prefetch)
return MadeChange;
Metrics.analyzeBasicBlock(*I, *TTI, EphValues);
}
unsigned LoopSize = Metrics.NumInsts;
if (!LoopSize)
LoopSize = 1;
unsigned ItersAhead = PrefDist/LoopSize;
if (!ItersAhead)
ItersAhead = 1;
SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>, 16> PrefLoads;
for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
I != IE; ++I) {
for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end();
J != JE; ++J) {
Value *PtrValue;
Instruction *MemI;
if (LoadInst *LMemI = dyn_cast<LoadInst>(J)) {
MemI = LMemI;
PtrValue = LMemI->getPointerOperand();
} else if (StoreInst *SMemI = dyn_cast<StoreInst>(J)) {
if (!PrefetchWrites) continue;
MemI = SMemI;
PtrValue = SMemI->getPointerOperand();
} else continue;
unsigned PtrAddrSpace = PtrValue->getType()->getPointerAddressSpace();
if (PtrAddrSpace)
continue;
if (L->isLoopInvariant(PtrValue))
continue;
const SCEV *LSCEV = SE->getSCEV(PtrValue);
const SCEVAddRecExpr *LSCEVAddRec = dyn_cast<SCEVAddRecExpr>(LSCEV);
if (!LSCEVAddRec)
continue;
// We don't want to double prefetch individual cache lines. If this load
// is known to be within one cache line of some other load that has
// already been prefetched, then don't prefetch this one as well.
bool DupPref = false;
for (SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>,
16>::iterator K = PrefLoads.begin(), KE = PrefLoads.end();
K != KE; ++K) {
const SCEV *PtrDiff = SE->getMinusSCEV(LSCEVAddRec, K->second);
if (const SCEVConstant *ConstPtrDiff =
dyn_cast<SCEVConstant>(PtrDiff)) {
int64_t PD = std::abs(ConstPtrDiff->getValue()->getSExtValue());
if (PD < (int64_t) CacheLineSize) {
DupPref = true;
break;
}
}
}
if (DupPref)
continue;
const SCEV *NextLSCEV = SE->getAddExpr(LSCEVAddRec, SE->getMulExpr(
SE->getConstant(LSCEVAddRec->getType(), ItersAhead),
LSCEVAddRec->getStepRecurrence(*SE)));
if (!isSafeToExpand(NextLSCEV, *SE))
continue;
PrefLoads.push_back(std::make_pair(MemI, LSCEVAddRec));
Type *I8Ptr = Type::getInt8PtrTy((*I)->getContext(), PtrAddrSpace);
SCEVExpander SCEVE(*SE, J->getModule()->getDataLayout(), "prefaddr");
Value *PrefPtrValue = SCEVE.expandCodeFor(NextLSCEV, I8Ptr, MemI);
IRBuilder<> Builder(MemI);
Module *M = (*I)->getParent()->getParent();
Type *I32 = Type::getInt32Ty((*I)->getContext());
Value *PrefetchFunc = Intrinsic::getDeclaration(M, Intrinsic::prefetch);
Builder.CreateCall(
PrefetchFunc,
{PrefPtrValue,
ConstantInt::get(I32, MemI->mayReadFromMemory() ? 0 : 1),
ConstantInt::get(I32, 3), ConstantInt::get(I32, 1)});
MadeChange = true;
}
}
return MadeChange;
}
// Reroll the provided loop with respect to the provided induction variable.
// Generally, we're looking for a loop like this:
//
// %iv = phi [ (preheader, ...), (body, %iv.next) ]
// f(%iv)
// %iv.1 = add %iv, 1 <-- a root increment
// f(%iv.1)
// %iv.2 = add %iv, 2 <-- a root increment
// f(%iv.2)
// %iv.scale_m_1 = add %iv, scale-1 <-- a root increment
// f(%iv.scale_m_1)
// ...
// %iv.next = add %iv, scale
// %cmp = icmp(%iv, ...)
// br %cmp, header, exit
//
// Notably, we do not require that f(%iv), f(%iv.1), etc. be isolated groups of
// instructions. In other words, the instructions in f(%iv), f(%iv.1), etc. can
// be intermixed with eachother. The restriction imposed by this algorithm is
// that the relative order of the isomorphic instructions in f(%iv), f(%iv.1),
// etc. be the same.
//
// First, we collect the use set of %iv, excluding the other increment roots.
// This gives us f(%iv). Then we iterate over the loop instructions (scale-1)
// times, having collected the use set of f(%iv.(i+1)), during which we:
// - Ensure that the next unmatched instruction in f(%iv) is isomorphic to
// the next unmatched instruction in f(%iv.(i+1)).
// - Ensure that both matched instructions don't have any external users
// (with the exception of last-in-chain reduction instructions).
// - Track the (aliasing) write set, and other side effects, of all
// instructions that belong to future iterations that come before the matched
// instructions. If the matched instructions read from that write set, then
// f(%iv) or f(%iv.(i+1)) has some dependency on instructions in
// f(%iv.(j+1)) for some j > i, and we cannot reroll the loop. Similarly,
// if any of these future instructions had side effects (could not be
// speculatively executed), and so do the matched instructions, when we
// cannot reorder those side-effect-producing instructions, and rerolling
// fails.
//
// Finally, we make sure that all loop instructions are either loop increment
// roots, belong to simple latch code, parts of validated reductions, part of
// f(%iv) or part of some f(%iv.i). If all of that is true (and all reductions
// have been validated), then we reroll the loop.
bool LoopReroll::reroll(Instruction *IV, Loop *L, BasicBlock *Header,
const SCEV *IterCount,
ReductionTracker &Reductions) {
const SCEVAddRecExpr *RealIVSCEV = cast<SCEVAddRecExpr>(SE->getSCEV(IV));
uint64_t Inc = cast<SCEVConstant>(RealIVSCEV->getOperand(1))->
getValue()->getZExtValue();
// The collection of loop increment instructions.
SmallInstructionVector LoopIncs;
uint64_t Scale = Inc;
// The effective induction variable, IV, is normally also the real induction
// variable. When we're dealing with a loop like:
// for (int i = 0; i < 500; ++i)
// x[3*i] = ...;
// x[3*i+1] = ...;
// x[3*i+2] = ...;
// then the real IV is still i, but the effective IV is (3*i).
Instruction *RealIV = IV;
if (Inc == 1 && !findScaleFromMul(RealIV, Scale, IV, LoopIncs))
return false;
assert(Scale <= MaxInc && "Scale is too large");
assert(Scale > 1 && "Scale must be at least 2");
// The set of increment instructions for each increment value.
SmallVector<SmallInstructionVector, 32> Roots(Scale-1);
SmallInstructionSet AllRoots;
if (!collectAllRoots(L, Inc, Scale, IV, Roots, AllRoots, LoopIncs))
return false;
DEBUG(dbgs() << "LRR: Found all root induction increments for: " <<
*RealIV << "\n");
// An array of just the possible reductions for this scale factor. When we
// collect the set of all users of some root instructions, these reduction
// instructions are treated as 'final' (their uses are not considered).
// This is important because we don't want the root use set to search down
// the reduction chain.
SmallInstructionSet PossibleRedSet;
SmallInstructionSet PossibleRedLastSet, PossibleRedPHISet;
Reductions.restrictToScale(Scale, PossibleRedSet, PossibleRedPHISet,
PossibleRedLastSet);
// We now need to check for equivalence of the use graph of each root with
// that of the primary induction variable (excluding the roots). Our goal
// here is not to solve the full graph isomorphism problem, but rather to
// catch common cases without a lot of work. As a result, we will assume
// that the relative order of the instructions in each unrolled iteration
// is the same (although we will not make an assumption about how the
// different iterations are intermixed). Note that while the order must be
// the same, the instructions may not be in the same basic block.
SmallInstructionSet Exclude(AllRoots);
Exclude.insert(LoopIncs.begin(), LoopIncs.end());
DenseSet<Instruction *> BaseUseSet;
collectInLoopUserSet(L, IV, Exclude, PossibleRedSet, BaseUseSet);
DenseSet<Instruction *> AllRootUses;
std::vector<DenseSet<Instruction *> > RootUseSets(Scale-1);
bool MatchFailed = false;
for (unsigned i = 0; i < Scale-1 && !MatchFailed; ++i) {
DenseSet<Instruction *> &RootUseSet = RootUseSets[i];
collectInLoopUserSet(L, Roots[i], SmallInstructionSet(),
PossibleRedSet, RootUseSet);
DEBUG(dbgs() << "LRR: base use set size: " << BaseUseSet.size() <<
" vs. iteration increment " << (i+1) <<
" use set size: " << RootUseSet.size() << "\n");
if (BaseUseSet.size() != RootUseSet.size()) {
MatchFailed = true;
break;
}
// In addition to regular aliasing information, we need to look for
// instructions from later (future) iterations that have side effects
// preventing us from reordering them past other instructions with side
// effects.
bool FutureSideEffects = false;
AliasSetTracker AST(*AA);
// The map between instructions in f(%iv.(i+1)) and f(%iv).
DenseMap<Value *, Value *> BaseMap;
assert(L->getNumBlocks() == 1 && "Cannot handle multi-block loops");
for (BasicBlock::iterator J1 = Header->begin(), J2 = Header->begin(),
JE = Header->end(); J1 != JE && !MatchFailed; ++J1) {
if (cast<Instruction>(J1) == RealIV)
continue;
if (cast<Instruction>(J1) == IV)
continue;
if (!BaseUseSet.count(J1))
continue;
if (PossibleRedPHISet.count(J1)) // Skip reduction PHIs.
continue;
while (J2 != JE && (!RootUseSet.count(J2) ||
std::find(Roots[i].begin(), Roots[i].end(), J2) !=
Roots[i].end())) {
// As we iterate through the instructions, instructions that don't
// belong to previous iterations (or the base case), must belong to
// future iterations. We want to track the alias set of writes from
// previous iterations.
if (!isa<PHINode>(J2) && !BaseUseSet.count(J2) &&
!AllRootUses.count(J2)) {
if (J2->mayWriteToMemory())
AST.add(J2);
// Note: This is specifically guarded by a check on isa<PHINode>,
// which while a valid (somewhat arbitrary) micro-optimization, is
// needed because otherwise isSafeToSpeculativelyExecute returns
// false on PHI nodes.
if (!isSimpleLoadStore(J2) && !isSafeToSpeculativelyExecute(J2, DL))
FutureSideEffects = true;
}
++J2;
}
if (!J1->isSameOperationAs(J2)) {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 << "\n");
MatchFailed = true;
break;
}
// Make sure that this instruction, which is in the use set of this
// root instruction, does not also belong to the base set or the set of
// some previous root instruction.
if (BaseUseSet.count(J2) || AllRootUses.count(J2)) {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 << " (prev. case overlap)\n");
MatchFailed = true;
break;
}
// Make sure that we don't alias with any instruction in the alias set
// tracker. If we do, then we depend on a future iteration, and we
// can't reroll.
if (J2->mayReadFromMemory()) {
for (AliasSetTracker::iterator K = AST.begin(), KE = AST.end();
K != KE && !MatchFailed; ++K) {
if (K->aliasesUnknownInst(J2, *AA)) {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 << " (depends on future store)\n");
MatchFailed = true;
break;
}
}
}
// If we've past an instruction from a future iteration that may have
// side effects, and this instruction might also, then we can't reorder
// them, and this matching fails. As an exception, we allow the alias
// set tracker to handle regular (simple) load/store dependencies.
if (FutureSideEffects &&
((!isSimpleLoadStore(J1) && !isSafeToSpeculativelyExecute(J1)) ||
(!isSimpleLoadStore(J2) && !isSafeToSpeculativelyExecute(J2)))) {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 <<
" (side effects prevent reordering)\n");
MatchFailed = true;
break;
}
// For instructions that are part of a reduction, if the operation is
// associative, then don't bother matching the operands (because we
// already know that the instructions are isomorphic, and the order
// within the iteration does not matter). For non-associative reductions,
// we do need to match the operands, because we need to reject
// out-of-order instructions within an iteration!
// For example (assume floating-point addition), we need to reject this:
// x += a[i]; x += b[i];
// x += a[i+1]; x += b[i+1];
// x += b[i+2]; x += a[i+2];
bool InReduction = Reductions.isPairInSame(J1, J2);
if (!(InReduction && J1->isAssociative())) {
bool Swapped = false, SomeOpMatched = false;;
for (unsigned j = 0; j < J1->getNumOperands() && !MatchFailed; ++j) {
Value *Op2 = J2->getOperand(j);
// If this is part of a reduction (and the operation is not
// associatve), then we match all operands, but not those that are
// part of the reduction.
if (InReduction)
if (Instruction *Op2I = dyn_cast<Instruction>(Op2))
if (Reductions.isPairInSame(J2, Op2I))
continue;
DenseMap<Value *, Value *>::iterator BMI = BaseMap.find(Op2);
if (BMI != BaseMap.end())
Op2 = BMI->second;
else if (std::find(Roots[i].begin(), Roots[i].end(),
(Instruction*) Op2) != Roots[i].end())
Op2 = IV;
if (J1->getOperand(Swapped ? unsigned(!j) : j) != Op2) {
// If we've not already decided to swap the matched operands, and
// we've not already matched our first operand (note that we could
// have skipped matching the first operand because it is part of a
// reduction above), and the instruction is commutative, then try
// the swapped match.
if (!Swapped && J1->isCommutative() && !SomeOpMatched &&
J1->getOperand(!j) == Op2) {
Swapped = true;
} else {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 << " (operand " << j << ")\n");
MatchFailed = true;
break;
}
}
SomeOpMatched = true;
}
}
if ((!PossibleRedLastSet.count(J1) && hasUsesOutsideLoop(J1, L)) ||
(!PossibleRedLastSet.count(J2) && hasUsesOutsideLoop(J2, L))) {
DEBUG(dbgs() << "LRR: iteration root match failed at " << *J1 <<
" vs. " << *J2 << " (uses outside loop)\n");
MatchFailed = true;
break;
}
if (!MatchFailed)
BaseMap.insert(std::pair<Value *, Value *>(J2, J1));
AllRootUses.insert(J2);
Reductions.recordPair(J1, J2, i+1);
++J2;
}
}
if (MatchFailed)
return false;
DEBUG(dbgs() << "LRR: Matched all iteration increments for " <<
*RealIV << "\n");
DenseSet<Instruction *> LoopIncUseSet;
collectInLoopUserSet(L, LoopIncs, SmallInstructionSet(),
SmallInstructionSet(), LoopIncUseSet);
DEBUG(dbgs() << "LRR: Loop increment set size: " <<
LoopIncUseSet.size() << "\n");
// Make sure that all instructions in the loop have been included in some
// use set.
for (BasicBlock::iterator J = Header->begin(), JE = Header->end();
J != JE; ++J) {
if (isa<DbgInfoIntrinsic>(J))
continue;
if (cast<Instruction>(J) == RealIV)
continue;
if (cast<Instruction>(J) == IV)
continue;
if (BaseUseSet.count(J) || AllRootUses.count(J) ||
(LoopIncUseSet.count(J) && (J->isTerminator() ||
isSafeToSpeculativelyExecute(J, DL))))
continue;
if (AllRoots.count(J))
continue;
if (Reductions.isSelectedPHI(J))
continue;
DEBUG(dbgs() << "LRR: aborting reroll based on " << *RealIV <<
" unprocessed instruction found: " << *J << "\n");
MatchFailed = true;
break;
}
if (MatchFailed)
return false;
DEBUG(dbgs() << "LRR: all instructions processed from " <<
*RealIV << "\n");
if (!Reductions.validateSelected())
return false;
// At this point, we've validated the rerolling, and we're committed to
// making changes!
Reductions.replaceSelected();
// Remove instructions associated with non-base iterations.
for (BasicBlock::reverse_iterator J = Header->rbegin();
J != Header->rend();) {
if (AllRootUses.count(&*J)) {
Instruction *D = &*J;
DEBUG(dbgs() << "LRR: removing: " << *D << "\n");
D->eraseFromParent();
continue;
}
++J;
}
// Insert the new induction variable.
const SCEV *Start = RealIVSCEV->getStart();
if (Inc == 1)
Start = SE->getMulExpr(Start,
SE->getConstant(Start->getType(), Scale));
const SCEVAddRecExpr *H =
cast<SCEVAddRecExpr>(SE->getAddRecExpr(Start,
SE->getConstant(RealIVSCEV->getType(), 1),
L, SCEV::FlagAnyWrap));
{ // Limit the lifetime of SCEVExpander.
SCEVExpander Expander(*SE, "reroll");
Value *NewIV = Expander.expandCodeFor(H, IV->getType(), Header->begin());
for (DenseSet<Instruction *>::iterator J = BaseUseSet.begin(),
JE = BaseUseSet.end(); J != JE; ++J)
(*J)->replaceUsesOfWith(IV, NewIV);
if (BranchInst *BI = dyn_cast<BranchInst>(Header->getTerminator())) {
if (LoopIncUseSet.count(BI)) {
const SCEV *ICSCEV = RealIVSCEV->evaluateAtIteration(IterCount, *SE);
if (Inc == 1)
ICSCEV =
SE->getMulExpr(ICSCEV, SE->getConstant(ICSCEV->getType(), Scale));
// Iteration count SCEV minus 1
const SCEV *ICMinus1SCEV =
SE->getMinusSCEV(ICSCEV, SE->getConstant(ICSCEV->getType(), 1));
Value *ICMinus1; // Iteration count minus 1
if (isa<SCEVConstant>(ICMinus1SCEV)) {
ICMinus1 = Expander.expandCodeFor(ICMinus1SCEV, NewIV->getType(), BI);
} else {
BasicBlock *Preheader = L->getLoopPreheader();
if (!Preheader)
Preheader = InsertPreheaderForLoop(L, this);
ICMinus1 = Expander.expandCodeFor(ICMinus1SCEV, NewIV->getType(),
Preheader->getTerminator());
}
Value *Cond = new ICmpInst(BI, CmpInst::ICMP_EQ, NewIV, ICMinus1,
"exitcond");
BI->setCondition(Cond);
if (BI->getSuccessor(1) != Header)
BI->swapSuccessors();
}
}
}
SimplifyInstructionsInBlock(Header, DL, TLI);
DeleteDeadPHIs(Header, TLI);
++NumRerolledLoops;
return true;
}
Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator &I) {
bool isLeftShift = I.getOpcode() == Instruction::Shl;
// See if we can propagate this shift into the input, this covers the trivial
// cast of lshr(shl(x,c1),c2) as well as other more complex cases.
if (I.getOpcode() != Instruction::AShr &&
CanEvaluateShifted(Op0, Op1->getZExtValue(), isLeftShift, *this)) {
DEBUG(dbgs() << "ICE: GetShiftedValue propagating shift through expression"
" to eliminate shift:\n IN: " << *Op0 << "\n SH: " << I <<"\n");
return ReplaceInstUsesWith(I,
GetShiftedValue(Op0, Op1->getZExtValue(), isLeftShift, *this));
}
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
// shl i32 X, 32 = 0 and srl i8 Y, 9 = 0, ... just don't eliminate
// a signed shift.
//
if (Op1->uge(TypeBits)) {
if (I.getOpcode() != Instruction::AShr)
return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
// ashr i32 X, 32 --> ashr i32 X, 31
I.setOperand(1, ConstantInt::get(I.getType(), TypeBits-1));
return &I;
}
// ((X*C1) << C2) == (X * (C1 << C2))
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
if (BO->getOpcode() == Instruction::Mul && isLeftShift)
if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
return BinaryOperator::CreateMul(BO->getOperand(0),
ConstantExpr::getShl(BOOp, Op1));
// Try to fold constant and into select arguments.
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
if (Instruction *R = FoldOpIntoSelect(I, SI))
return R;
if (isa<PHINode>(Op0))
if (Instruction *NV = FoldOpIntoPhi(I))
return NV;
// Fold shift2(trunc(shift1(x,c1)), c2) -> trunc(shift2(shift1(x,c1),c2))
if (TruncInst *TI = dyn_cast<TruncInst>(Op0)) {
Instruction *TrOp = dyn_cast<Instruction>(TI->getOperand(0));
// If 'shift2' is an ashr, we would have to get the sign bit into a funny
// place. Don't try to do this transformation in this case. Also, we
// require that the input operand is a shift-by-constant so that we have
// confidence that the shifts will get folded together. We could do this
// xform in more cases, but it is unlikely to be profitable.
if (TrOp && I.isLogicalShift() && TrOp->isShift() &&
isa<ConstantInt>(TrOp->getOperand(1))) {
// Okay, we'll do this xform. Make the shift of shift.
Constant *ShAmt = ConstantExpr::getZExt(Op1, TrOp->getType());
// (shift2 (shift1 & 0x00FF), c2)
Value *NSh = Builder->CreateBinOp(I.getOpcode(), TrOp, ShAmt,I.getName());
// For logical shifts, the truncation has the effect of making the high
// part of the register be zeros. Emulate this by inserting an AND to
// clear the top bits as needed. This 'and' will usually be zapped by
// other xforms later if dead.
unsigned SrcSize = TrOp->getType()->getScalarSizeInBits();
unsigned DstSize = TI->getType()->getScalarSizeInBits();
APInt MaskV(APInt::getLowBitsSet(SrcSize, DstSize));
// The mask we constructed says what the trunc would do if occurring
// between the shifts. We want to know the effect *after* the second
// shift. We know that it is a logical shift by a constant, so adjust the
// mask as appropriate.
if (I.getOpcode() == Instruction::Shl)
MaskV <<= Op1->getZExtValue();
else {
assert(I.getOpcode() == Instruction::LShr && "Unknown logical shift");
MaskV = MaskV.lshr(Op1->getZExtValue());
}
// shift1 & 0x00FF
Value *And = Builder->CreateAnd(NSh,
ConstantInt::get(I.getContext(), MaskV),
TI->getName());
// Return the value truncated to the interesting size.
return new TruncInst(And, I.getType());
}
}
if (Op0->hasOneUse()) {
if (BinaryOperator *Op0BO = dyn_cast<BinaryOperator>(Op0)) {
// Turn ((X >> C) + Y) << C -> (X + (Y << C)) & (~0 << C)
Value *V1, *V2;
ConstantInt *CC;
switch (Op0BO->getOpcode()) {
default: break;
case Instruction::Add:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
// These operators commute.
// Turn (Y + (X >> C)) << C -> (X + (Y << C)) & (~0 << C)
if (isLeftShift && Op0BO->getOperand(1)->hasOneUse() &&
match(Op0BO->getOperand(1), m_Shr(m_Value(V1),
m_Specific(Op1)))) {
Value *YS = // (Y << C)
Builder->CreateShl(Op0BO->getOperand(0), Op1, Op0BO->getName());
// (X + (Y << C))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), YS, V1,
Op0BO->getOperand(1)->getName());
uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
}
// Turn (Y + ((X >> C) & CC)) << C -> ((X & (CC << C)) + (Y << C))
Value *Op0BOOp1 = Op0BO->getOperand(1);
if (isLeftShift && Op0BOOp1->hasOneUse() &&
match(Op0BOOp1,
m_And(m_OneUse(m_Shr(m_Value(V1), m_Specific(Op1))),
m_ConstantInt(CC)))) {
Value *YS = // (Y << C)
Builder->CreateShl(Op0BO->getOperand(0), Op1,
Op0BO->getName());
// X & (CC << C)
Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
V1->getName()+".mask");
return BinaryOperator::Create(Op0BO->getOpcode(), YS, XM);
}
}
// FALL THROUGH.
case Instruction::Sub: {
// Turn ((X >> C) + Y) << C -> (X + (Y << C)) & (~0 << C)
if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
match(Op0BO->getOperand(0), m_Shr(m_Value(V1),
m_Specific(Op1)))) {
Value *YS = // (Y << C)
Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
// (X + (Y << C))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), V1, YS,
Op0BO->getOperand(0)->getName());
uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
}
// Turn (((X >> C)&CC) + Y) << C -> (X + (Y << C)) & (CC << C)
if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
match(Op0BO->getOperand(0),
m_And(m_OneUse(m_Shr(m_Value(V1), m_Value(V2))),
m_ConstantInt(CC))) && V2 == Op1) {
Value *YS = // (Y << C)
Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
// X & (CC << C)
Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
V1->getName()+".mask");
return BinaryOperator::Create(Op0BO->getOpcode(), XM, YS);
}
break;
}
}
// If the operand is an bitwise operator with a constant RHS, and the
// shift is the only use, we can pull it out of the shift.
if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
bool isValid = true; // Valid only for And, Or, Xor
bool highBitSet = false; // Transform if high bit of constant set?
switch (Op0BO->getOpcode()) {
default: isValid = false; break; // Do not perform transform!
case Instruction::Add:
isValid = isLeftShift;
break;
case Instruction::Or:
case Instruction::Xor:
highBitSet = false;
break;
case Instruction::And:
highBitSet = true;
break;
}
// If this is a signed shift right, and the high bit is modified
// by the logical operation, do not perform the transformation.
// The highBitSet boolean indicates the value of the high bit of
// the constant which would cause it to be modified for this
// operation.
//
if (isValid && I.getOpcode() == Instruction::AShr)
isValid = Op0C->getValue()[TypeBits-1] == highBitSet;
if (isValid) {
Constant *NewRHS = ConstantExpr::get(I.getOpcode(), Op0C, Op1);
Value *NewShift =
Builder->CreateBinOp(I.getOpcode(), Op0BO->getOperand(0), Op1);
NewShift->takeName(Op0BO);
return BinaryOperator::Create(Op0BO->getOpcode(), NewShift,
NewRHS);
}
}
}
}
// Find out if this is a shift of a shift by a constant.
BinaryOperator *ShiftOp = dyn_cast<BinaryOperator>(Op0);
if (ShiftOp && !ShiftOp->isShift())
ShiftOp = 0;
if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
// This is a constant shift of a constant shift. Be careful about hiding
// shl instructions behind bit masks. They are used to represent multiplies
// by a constant, and it is important that simple arithmetic expressions
// are still recognizable by scalar evolution.
//
// The transforms applied to shl are very similar to the transforms applied
// to mul by constant. We can be more aggressive about optimizing right
// shifts.
//
// Combinations of right and left shifts will still be optimized in
// DAGCombine where scalar evolution no longer applies.
ConstantInt *ShiftAmt1C = cast<ConstantInt>(ShiftOp->getOperand(1));
uint32_t ShiftAmt1 = ShiftAmt1C->getLimitedValue(TypeBits);
uint32_t ShiftAmt2 = Op1->getLimitedValue(TypeBits);
assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
if (ShiftAmt1 == 0) return 0; // Will be simplified in the future.
Value *X = ShiftOp->getOperand(0);
IntegerType *Ty = cast<IntegerType>(I.getType());
// Check for (X << c1) << c2 and (X >> c1) >> c2
if (I.getOpcode() == ShiftOp->getOpcode()) {
uint32_t AmtSum = ShiftAmt1+ShiftAmt2; // Fold into one big shift.
// If this is oversized composite shift, then unsigned shifts get 0, ashr
// saturates.
if (AmtSum >= TypeBits) {
if (I.getOpcode() != Instruction::AShr)
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
AmtSum = TypeBits-1; // Saturate to 31 for i32 ashr.
}
return BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, AmtSum));
}
if (ShiftAmt1 == ShiftAmt2) {
// If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
if (I.getOpcode() == Instruction::LShr &&
ShiftOp->getOpcode() == Instruction::Shl) {
APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt1));
return BinaryOperator::CreateAnd(X,
ConstantInt::get(I.getContext(), Mask));
}
} else if (ShiftAmt1 < ShiftAmt2) {
uint32_t ShiftDiff = ShiftAmt2-ShiftAmt1;
// (X >>?,exact C1) << C2 --> X << (C2-C1)
// The inexact version is deferred to DAGCombine so we don't hide shl
// behind a bit mask.
if (I.getOpcode() == Instruction::Shl &&
ShiftOp->getOpcode() != Instruction::Shl &&
ShiftOp->isExact()) {
assert(ShiftOp->getOpcode() == Instruction::LShr ||
ShiftOp->getOpcode() == Instruction::AShr);
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
BinaryOperator *NewShl = BinaryOperator::Create(Instruction::Shl,
X, ShiftDiffCst);
NewShl->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
NewShl->setHasNoSignedWrap(I.hasNoSignedWrap());
return NewShl;
}
// (X << C1) >>u C2 --> X >>u (C2-C1) & (-1 >> C2)
if (I.getOpcode() == Instruction::LShr &&
ShiftOp->getOpcode() == Instruction::Shl) {
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
// (X <<nuw C1) >>u C2 --> X >>u (C2-C1)
if (ShiftOp->hasNoUnsignedWrap()) {
BinaryOperator *NewLShr = BinaryOperator::Create(Instruction::LShr,
X, ShiftDiffCst);
NewLShr->setIsExact(I.isExact());
return NewLShr;
}
Value *Shift = Builder->CreateLShr(X, ShiftDiffCst);
APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
return BinaryOperator::CreateAnd(Shift,
ConstantInt::get(I.getContext(),Mask));
}
// We can't handle (X << C1) >>s C2, it shifts arbitrary bits in. However,
// we can handle (X <<nsw C1) >>s C2 since it only shifts in sign bits.
if (I.getOpcode() == Instruction::AShr &&
ShiftOp->getOpcode() == Instruction::Shl) {
if (ShiftOp->hasNoSignedWrap()) {
// (X <<nsw C1) >>s C2 --> X >>s (C2-C1)
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
BinaryOperator *NewAShr = BinaryOperator::Create(Instruction::AShr,
X, ShiftDiffCst);
NewAShr->setIsExact(I.isExact());
return NewAShr;
}
}
} else {
assert(ShiftAmt2 < ShiftAmt1);
uint32_t ShiftDiff = ShiftAmt1-ShiftAmt2;
// (X >>?exact C1) << C2 --> X >>?exact (C1-C2)
// The inexact version is deferred to DAGCombine so we don't hide shl
// behind a bit mask.
if (I.getOpcode() == Instruction::Shl &&
ShiftOp->getOpcode() != Instruction::Shl &&
ShiftOp->isExact()) {
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
BinaryOperator *NewShr = BinaryOperator::Create(ShiftOp->getOpcode(),
X, ShiftDiffCst);
NewShr->setIsExact(true);
return NewShr;
}
// (X << C1) >>u C2 --> X << (C1-C2) & (-1 >> C2)
if (I.getOpcode() == Instruction::LShr &&
ShiftOp->getOpcode() == Instruction::Shl) {
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
if (ShiftOp->hasNoUnsignedWrap()) {
// (X <<nuw C1) >>u C2 --> X <<nuw (C1-C2)
BinaryOperator *NewShl = BinaryOperator::Create(Instruction::Shl,
X, ShiftDiffCst);
NewShl->setHasNoUnsignedWrap(true);
return NewShl;
}
Value *Shift = Builder->CreateShl(X, ShiftDiffCst);
APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
return BinaryOperator::CreateAnd(Shift,
ConstantInt::get(I.getContext(),Mask));
}
// We can't handle (X << C1) >>s C2, it shifts arbitrary bits in. However,
// we can handle (X <<nsw C1) >>s C2 since it only shifts in sign bits.
if (I.getOpcode() == Instruction::AShr &&
ShiftOp->getOpcode() == Instruction::Shl) {
if (ShiftOp->hasNoSignedWrap()) {
// (X <<nsw C1) >>s C2 --> X <<nsw (C1-C2)
ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
BinaryOperator *NewShl = BinaryOperator::Create(Instruction::Shl,
X, ShiftDiffCst);
NewShl->setHasNoSignedWrap(true);
return NewShl;
}
}
}
}
return 0;
}
Formula* EncoderPass::makeTraceFormula() {
MSTimer timer1;
if(options->printDuration()) {
timer1.start();
}
// Create an empty trace formula
Formula *formula = new Formula();
// Prepare the CFG variables
encoder->prepareControlFlow(targetFun);
// Pre-process the global variables
initGlobalVariables();
// Save the line numbers of the call to assert
initAssertCalls();
bool isWeigted = false;
unsigned oldLine = 0;
Instruction *lastInstruction = NULL;
std::vector<ExprPtr> currentConstraits;
// Iterate through the function in Topological Order
// encode each instructions in SMT constraints
// @See: eli.thegreenplace.net/2013/09/16/analyzing-function-cfgs-with-llvm/
ReversePostOrderTraversal<Function*> RPOT(this->targetFun);
ReversePostOrderTraversal<Function*>::rpo_iterator itb;
for (itb=RPOT.begin(); itb!=RPOT.end(); ++itb) {
BasicBlock *bb = *itb;
// Propagate pointers when we enter in a new basicblock
ExprPtr e = ctx->propagatePointers(bb);
if (e) {
e->setHard();
formula->add(e);
}
// HFTF: Encode bug free blocks as hard
bool doEncodeBB = true;
if (options->htfUsed()) {
if(profile->isBugFreeBlock(bb)) {
doEncodeBB = false;
}
}
// Iterate through the basicblocks
for (BasicBlock::iterator iti=bb->begin(), eti=bb->end();
iti!=eti; ++iti) {
Instruction *i = iti;
bool doEncodeInst = doEncodeBB;
// Check the line number
unsigned line = 0;
if (MDNode *N = i->getMetadata("dbg")) {
DILocation Loc(N);
line = Loc.getLineNumber();
// Instruction related to an assert
if (ctx->isAssertCall(line)) {
isWeigted = false;
doEncodeInst = true;
} else {
// Instruction with line number
// (not related to an assert)
isWeigted = true;
}
} else {
// Instruction with no line number
isWeigted = false;
}
// Hardened Trace Formula
if (options->htfUsed() && !doEncodeInst) {
isWeigted = false;
}
// Encode the instruction in a SMT formula
ExprPtr expr = NULL;
switch (i->getOpcode()) {
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
expr = encoder->encode(cast<BinaryOperator>(i));
break;
case Instruction::Select:
expr = encoder->encode(cast<SelectInst>(i));
break;
case Instruction::PHI:
expr = encoder->encode(cast<PHINode>(i));
isWeigted = false;
break;
case Instruction::Br:
expr = encoder->encode(cast<BranchInst>(i), loops);
isWeigted = false;
break;
case Instruction::Switch:
expr = encoder->encode(cast<SwitchInst>(i));
break;
case Instruction::ICmp:
expr = encoder->encode(cast<ICmpInst>(i));
break;
case Instruction::Call:
expr = encoder->encode(cast<CallInst>(i), preCond, postCond);
if (!expr) {
// Do not encode sniper_x functions.
continue;
}
isWeigted = false;
break;
case Instruction::Alloca:
expr = encoder->encode(cast<AllocaInst>(i));
if (!expr) {
continue;
}
isWeigted = false;
break;
case Instruction::Store:
expr = encoder->encode(cast<StoreInst>(i));
break;
case Instruction::Load:
expr = encoder->encode(cast<LoadInst>(i), postCond);
break;
case Instruction::GetElementPtr:
expr = encoder->encode(cast<GetElementPtrInst>(i));
isWeigted = false;
break;
case Instruction::SExt:
expr = encoder->encode(cast<SExtInst>(i));
isWeigted = false;
break;
case Instruction::ZExt:
expr = encoder->encode(cast<ZExtInst>(i));
isWeigted = false;
break;
case Instruction::Ret:
expr = encoder->encode(cast<ReturnInst>(i));
isWeigted = false;
break;
case Instruction::Unreachable:
// Do not encode.
continue;
case Instruction::PtrToInt: {
// Instruction added by SNIPER
std::string instName = i->getName().str();
std::string prefix("sniper_ptrVal");
if (!instName.compare(0, prefix.size(), prefix)) {
continue;
}
// NO BREAK!
}
case Instruction::VAArg:
case Instruction::Invoke:
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::IntToPtr:
case Instruction::BitCast:
case Instruction::FCmp:
case Instruction::ExtractElement:
case Instruction::InsertElement:
case Instruction::ShuffleVector:
case Instruction::ExtractValue:
case Instruction::InsertValue:
i->dump();
assert("unsupported LLVM instruction!\n");
break;
default:
llvm_unreachable("Illegal opcode!");
}
assert(expr && "Expression is null!");
// Atoi checking
if (isAtoiFunction(i)) {
isWeigted = false;
}
// Instruction with line number
if (isWeigted) {
// Add each instruction separately
if (options->instructionGranularityLevel()) {
expr->setInstruction(i);
expr->setSoft();
formula->add(expr);
}
// Pack and add all instructions from
// the same line number
else if (options->lineGranularityLevel()) {
assert(line>0 && "Illegal line number!");
// New line, Add the collect constraints to the formula
if (line!=oldLine && oldLine!=0) {
assert(!currentConstraits.empty() && "No constraints!");
assert(lastInstruction && "Instruction is null!");
ExprPtr e = Expression::mkAnd(currentConstraits);
e->setInstruction(lastInstruction);
e->setSoft();
formula->add(e);
currentConstraits.clear();
}
currentConstraits.push_back(expr);
oldLine = line;
lastInstruction = i;
}
// Block level
else if (options->blockGranularityLevel()) {
currentConstraits.push_back(expr);
} else {
assert("Unknow granularity level!");
}
}
// Instruction with no line number
else {
expr->setHard();
formula->add(expr);
}
}
// End of basic block iteration
if (options->blockGranularityLevel()) {
if (!currentConstraits.empty()) {
ExprPtr e = Expression::mkAnd(currentConstraits);
e->setInstruction(lastInstruction);
e->setSoft();
formula->add(e);
currentConstraits.clear();
}
}
}
// Add the remaining soft constraints to the formula
if (!currentConstraits.empty()) {
assert(options->lineGranularityLevel()
&& "Some instructions could not be encoded!");
assert(lastInstruction && "Instruction is null!");
ExprPtr e = Expression::mkAnd(currentConstraits);
e->setInstruction(lastInstruction);
e->setSoft();
formula->add(e);
currentConstraits.clear();
}
if(options->printDuration()) {
timer1.stop("Trace Formula Encoding Time");
}
return formula;
}
/// SimplifyWithOpReplaced - See if V simplifies when its operand Op is
/// replaced with RepOp.
static Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
const DataLayout *TD,
const TargetLibraryInfo *TLI) {
// Trivial replacement.
if (V == Op)
return RepOp;
Instruction *I = dyn_cast<Instruction>(V);
if (!I)
return nullptr;
// If this is a binary operator, try to simplify it with the replaced op.
if (BinaryOperator *B = dyn_cast<BinaryOperator>(I)) {
if (B->getOperand(0) == Op)
return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), TD, TLI);
if (B->getOperand(1) == Op)
return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, TD, TLI);
}
// Same for CmpInsts.
if (CmpInst *C = dyn_cast<CmpInst>(I)) {
if (C->getOperand(0) == Op)
return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), TD,
TLI);
if (C->getOperand(1) == Op)
return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, TD,
TLI);
}
// TODO: We could hand off more cases to instsimplify here.
// If all operands are constant after substituting Op for RepOp then we can
// constant fold the instruction.
if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
// Build a list of all constant operands.
SmallVector<Constant*, 8> ConstOps;
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
if (I->getOperand(i) == Op)
ConstOps.push_back(CRepOp);
else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
ConstOps.push_back(COp);
else
break;
}
// All operands were constants, fold it.
if (ConstOps.size() == I->getNumOperands()) {
if (CmpInst *C = dyn_cast<CmpInst>(I))
return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
ConstOps[1], TD, TLI);
if (LoadInst *LI = dyn_cast<LoadInst>(I))
if (!LI->isVolatile())
return ConstantFoldLoadFromConstPtr(ConstOps[0], TD);
return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
ConstOps, TD, TLI);
}
}
return nullptr;
}
static MemoryAccessKind checkFunctionMemoryAccess(Function &F, AAResults &AAR,
const SCCNodeSet &SCCNodes) {
FunctionModRefBehavior MRB = AAR.getModRefBehavior(&F);
if (MRB == FMRB_DoesNotAccessMemory)
// Already perfect!
return MAK_ReadNone;
// Definitions with weak linkage may be overridden at linktime with
// something that writes memory, so treat them like declarations.
if (F.isDeclaration() || F.mayBeOverridden()) {
if (AliasAnalysis::onlyReadsMemory(MRB))
return MAK_ReadOnly;
// Conservatively assume it writes to memory.
return MAK_MayWrite;
}
// Scan the function body for instructions that may read or write memory.
bool ReadsMemory = false;
for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
Instruction *I = &*II;
// Some instructions can be ignored even if they read or write memory.
// Detect these now, skipping to the next instruction if one is found.
CallSite CS(cast<Value>(I));
if (CS) {
// Ignore calls to functions in the same SCC, as long as the call sites
// don't have operand bundles. Calls with operand bundles are allowed to
// have memory effects not described by the memory effects of the call
// target.
if (!CS.hasOperandBundles() && CS.getCalledFunction() &&
SCCNodes.count(CS.getCalledFunction()))
continue;
FunctionModRefBehavior MRB = AAR.getModRefBehavior(CS);
// If the call doesn't access memory, we're done.
if (!(MRB & MRI_ModRef))
continue;
if (!AliasAnalysis::onlyAccessesArgPointees(MRB)) {
// The call could access any memory. If that includes writes, give up.
if (MRB & MRI_Mod)
return MAK_MayWrite;
// If it reads, note it.
if (MRB & MRI_Ref)
ReadsMemory = true;
continue;
}
// Check whether all pointer arguments point to local memory, and
// ignore calls that only access local memory.
for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
CI != CE; ++CI) {
Value *Arg = *CI;
if (!Arg->getType()->isPtrOrPtrVectorTy())
continue;
AAMDNodes AAInfo;
I->getAAMetadata(AAInfo);
MemoryLocation Loc(Arg, MemoryLocation::UnknownSize, AAInfo);
// Skip accesses to local or constant memory as they don't impact the
// externally visible mod/ref behavior.
if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
if (MRB & MRI_Mod)
// Writes non-local memory. Give up.
return MAK_MayWrite;
if (MRB & MRI_Ref)
// Ok, it reads non-local memory.
ReadsMemory = true;
}
continue;
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
// Ignore non-volatile loads from local memory. (Atomic is okay here.)
if (!LI->isVolatile()) {
MemoryLocation Loc = MemoryLocation::get(LI);
if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
// Ignore non-volatile stores to local memory. (Atomic is okay here.)
if (!SI->isVolatile()) {
MemoryLocation Loc = MemoryLocation::get(SI);
if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
} else if (VAArgInst *VI = dyn_cast<VAArgInst>(I)) {
// Ignore vaargs on local memory.
MemoryLocation Loc = MemoryLocation::get(VI);
if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
continue;
}
// Any remaining instructions need to be taken seriously! Check if they
// read or write memory.
if (I->mayWriteToMemory())
// Writes memory. Just give up.
return MAK_MayWrite;
// If this instruction may read memory, remember that.
ReadsMemory |= I->mayReadFromMemory();
}
return ReadsMemory ? MAK_ReadOnly : MAK_ReadNone;
}