static bool isLessThan(SILValue Start, SILValue End) {
auto S = dyn_cast<IntegerLiteralInst>(Start.getDef());
if (!S)
return false;
auto E = dyn_cast<IntegerLiteralInst>(End.getDef());
if (!E)
return false;
return S->getValue().slt(E->getValue());
}
// Get the pair of array and index. Because we want to disambiguate between the
// two types of check bounds checks merge in the type into the lower bit of one
// of the addresse index.
static std::pair<ValueBase *, ArrayAccessDesc>
getArrayIndexPair(SILValue Array, SILValue ArrayIndex, ArrayCallKind K) {
assert((K == ArrayCallKind::kCheckIndex ||
K == ArrayCallKind::kCheckSubscript) &&
"Must be a bounds check call");
return std::make_pair(
Array.getDef(),
ArrayAccessDesc(ArrayIndex.getDef(), K == ArrayCallKind::kCheckIndex));
}
/// Two allocations of a mutable array struct cannot reference the same
/// storage after modification. So we can treat them as not aliasing for the
/// purpose of bound checking. The change would only be tracked through one of
/// the allocations.
static bool isIdentifiedUnderlyingArrayObject(SILValue V) {
// Allocations are safe.
if (isa<AllocationInst>(V.getDef()))
return true;
// Function arguments are safe.
if (auto Arg = dyn_cast<SILArgument>(V.getDef()))
return Arg->isFunctionArg();
return false;
}
AliasKeyTy AliasAnalysis::toAliasKey(SILValue V1, SILValue V2,
SILType Type1, SILType Type2) {
size_t idx1 = AliasValueBaseToIndex.getIndex(V1.getDef());
assert(idx1 != std::numeric_limits<size_t>::max() &&
"~0 index reserved for empty/tombstone keys");
size_t idx2 = AliasValueBaseToIndex.getIndex(V2.getDef());
assert(idx2 != std::numeric_limits<size_t>::max() &&
"~0 index reserved for empty/tombstone keys");
void *t1 = Type1.getOpaqueValue();
void *t2 = Type2.getOpaqueValue();
return {idx1, idx2, t1, t2};
}
/// Check if the root value for Value that comes
/// along the path from DomBB is equivalent to the
/// DomCondition.
SILValue CheckedCastBrJumpThreading::isArgValueEquivalentToCondition(
SILValue Value, SILBasicBlock *DomBB, SILValue DomValue,
DominanceInfo *DT) {
SmallPtrSet<ValueBase *, 16> SeenValues;
DomValue = DomValue.stripClassCasts();
while (true) {
Value = Value.stripClassCasts();
if (Value == DomValue)
return Value;
// We know how to propagate through BBArgs only.
auto *V = dyn_cast<SILArgument>(Value);
if (!V)
return SILValue();
// Have we visited this BB already?
if (!SeenValues.insert(Value.getDef()).second)
return SILValue();
if (SeenValues.size() > 10)
return SILValue();
SmallVector<SILValue, 4> IncomingValues;
if (!V->getIncomingValues(IncomingValues) || IncomingValues.empty())
return SILValue();
ValueBase *Def = nullptr;
for (auto IncomingValue : IncomingValues) {
// Each incoming value should be either from a block
// dominated by DomBB or it should be the value used in
// condition in DomBB
Value = IncomingValue.stripClassCasts();
if (Value == DomValue)
continue;
// Values should be the same
if (!Def)
Def = Value.getDef();
if (Def != Value.getDef())
return SILValue();
if (!DT->dominates(DomBB, Value.getDef()->getParentBB()))
return SILValue();
// OK, this value is a potential candidate
}
Value = IncomingValues[0];
}
}
bool
swift::
mayGuaranteedUseValue(SILInstruction *User, SILValue Ptr, AliasAnalysis *AA) {
// Only full apply sites can require a guaranteed lifetime. If we don't have
// one, bail.
if (!isa<FullApplySite>(User))
return false;
FullApplySite FAS(User);
// Ok, we have a full apply site. If the apply has no arguments, we don't need
// to worry about any guaranteed parameters.
if (!FAS.getNumArguments())
return false;
// Ok, we have an apply site with arguments. Look at the function type and
// iterate through the function parameters. If any of the parameters are
// guaranteed, attempt to prove that the passed in parameter cannot alias
// Ptr. If we fail, return true.
CanSILFunctionType FType = FAS.getSubstCalleeType();
auto Params = FType->getParameters();
for (unsigned i : indices(Params)) {
if (!Params[i].isGuaranteed())
continue;
SILValue Op = FAS.getArgument(i);
for (int i = 0, e = Ptr->getNumTypes(); i < e; i++)
if (!AA->isNoAlias(Op, SILValue(Ptr.getDef(), i)))
return true;
}
// Ok, we were able to prove that all arguments to the apply that were
// guaranteed do not alias Ptr. Return false.
return false;
}
static SILValue stripRCIdentityPreservingInsts(SILValue V) {
// First strip off RC identity preserving casts.
if (isRCIdentityPreservingCast(V->getKind()))
return cast<SILInstruction>(V.getDef())->getOperand(0);
// Then if we have a struct_extract that is extracting a non-trivial member
// from a struct with no other non-trivial members, a ref count operation on
// the struct is equivalent to a ref count operation on the extracted
// member. Strip off the extract.
if (auto *SEI = dyn_cast<StructExtractInst>(V))
if (SEI->isFieldOnlyNonTrivialField())
return SEI->getOperand();
// If we have a struct instruction with only one non-trivial stored field, the
// only reference count that can be modified is the non-trivial field. Return
// the non-trivial field.
if (auto *SI = dyn_cast<StructInst>(V))
if (SILValue NewValue = SI->getUniqueNonTrivialFieldValue())
return NewValue;
// If we have an unchecked_enum_data, strip off the unchecked_enum_data.
if (auto *UEDI = dyn_cast<UncheckedEnumDataInst>(V))
return UEDI->getOperand();
// If we have an enum instruction with a payload, strip off the enum to
// expose the enum's payload.
if (auto *EI = dyn_cast<EnumInst>(V))
if (EI->hasOperand())
return EI->getOperand();
// If we have a tuple_extract that is extracting the only non trivial member
// of a tuple, a retain_value on the tuple is equivalent to a retain_value on
// the extracted value.
if (auto *TEI = dyn_cast<TupleExtractInst>(V))
if (TEI->isEltOnlyNonTrivialElt())
return TEI->getOperand();
// If we are forming a tuple and the tuple only has one element with reference
// semantics, a retain_value on the tuple is equivalent to a retain value on
// the tuple operand.
if (auto *TI = dyn_cast<TupleInst>(V))
if (SILValue NewValue = TI->getUniqueNonTrivialElt())
return NewValue;
// Any SILArgument with a single predecessor from a "phi" perspective is
// dead. In such a case, the SILArgument must be rc-identical.
//
// This is the easy case. The difficult case is when you have an argument with
// /multiple/ predecessors.
//
// We do not need to insert this SILArgument into the visited SILArgument set
// since we will only visit it twice if we go around a back edge due to a
// different SILArgument that is actually being used for its phi node like
// purposes.
if (auto *A = dyn_cast<SILArgument>(V))
if (SILValue Result = A->getSingleIncomingValue())
return Result;
return SILValue();
}
static bool canApplyDecrementRefCount(OperandValueArrayRef Ops, SILValue Ptr,
AliasAnalysis *AA) {
// Ok, this apply *MAY* decrement ref counts. Now our strategy is to attempt
// to use properties of the pointer, the function's arguments, and the
// function itself to prove that the pointer cannot have its ref count
// affected by the applied function.
// TODO: Put in function property check section here when we get access to
// such information.
// First make sure that the underlying object of ptr is a local object which
// does not escape. This prevents the apply from indirectly via the global
// affecting the reference count of the pointer.
if (!isNonEscapingLocalObject(getUnderlyingObject(Ptr)))
return true;
// Now that we know that the function can not affect the pointer indirectly,
// make sure that the apply can not affect the pointer directly via the
// applies arguments by proving that the pointer can not alias any of the
// functions arguments.
for (auto Op : Ops) {
for (int i = 0, e = Ptr->getNumTypes(); i < e; i++) {
if (!AA->isNoAlias(Op, SILValue(Ptr.getDef(), i)))
return true;
}
}
// Success! The apply inst can not affect the reference count of ptr!
return false;
}
static bool canHoistArrayArgument(ApplyInst *SemanticsCall, SILValue Arr,
SILInstruction *InsertBefore,
DominanceInfo *DT) {
// We only know how to hoist inout, owned or guaranteed parameters.
auto Convention = getSelfParameterConvention(SemanticsCall);
if (Convention != ParameterConvention::Indirect_Inout &&
Convention != ParameterConvention::Direct_Owned &&
Convention != ParameterConvention::Direct_Guaranteed)
return false;
auto *SelfVal = Arr.getDef();
auto *SelfBB = SelfVal->getParentBB();
if (DT->dominates(SelfBB, InsertBefore->getParent()))
return true;
if (auto LI = dyn_cast<LoadInst>(SelfVal)) {
// Are we loading a value from an address in a struct defined at a point
// dominating the hoist point.
auto Val = LI->getOperand().getDef();
bool DoesNotDominate;
StructElementAddrInst *SEI;
while ((DoesNotDominate = !DT->dominates(Val->getParentBB(),
InsertBefore->getParent())) &&
(SEI = dyn_cast<StructElementAddrInst>(Val)))
Val = SEI->getOperand().getDef();
return DoesNotDominate == false;
}
return false;
}
SILValue SILValue::stripIndexingInsts() {
SILValue V = *this;
while (true) {
if (!isa<IndexingInst>(V.getDef()))
return V;
V = cast<IndexingInst>(V)->getBase();
}
}
static void mapOperands(SILInstruction *I,
const llvm::DenseMap<ValueBase *, SILValue> &ValueMap) {
for (auto &Opd : I->getAllOperands()) {
SILValue OrigVal = Opd.get();
ValueBase *OrigDef = OrigVal.getDef();
auto Found = ValueMap.find(OrigDef);
if (Found != ValueMap.end()) {
SILValue MappedVal = Found->second;
unsigned ResultIdx = OrigVal.getResultNumber();
// All mapped instructions have their result number set to zero. Except
// for arguments that we followed along one edge to their incoming value
// on that edge.
if (isa<SILArgument>(OrigDef))
ResultIdx = MappedVal.getResultNumber();
Opd.set(SILValue(MappedVal.getDef(), ResultIdx));
}
}
}
/// Analyse one potential induction variable starting at Arg.
InductionInfo *analyseIndVar(SILArgument *HeaderVal, BuiltinInst *Inc,
IntegerLiteralInst *IncVal) {
if (IncVal->getValue() != 1)
return nullptr;
// Find the start value.
auto *PreheaderTerm = dyn_cast<BranchInst>(Preheader->getTerminator());
if (!PreheaderTerm)
return nullptr;
auto Start = PreheaderTerm->getArg(HeaderVal->getIndex());
// Find the exit condition.
auto CondBr = dyn_cast<CondBranchInst>(ExitingBlk->getTerminator());
if (!CondBr)
return nullptr;
if (ExitBlk == CondBr->getFalseBB())
return nullptr;
assert(ExitBlk == CondBr->getTrueBB() &&
"The loop's exiting blocks terminator must exit");
auto Cond = CondBr->getCondition();
SILValue End;
// Look for a compare of induction variable + 1.
// TODO: obviously we need to handle many more patterns.
if (!match(Cond, m_ApplyInst(BuiltinValueKind::ICMP_EQ,
m_TupleExtractInst(m_Specific(Inc), 0),
m_SILValue(End))) &&
!match(Cond,
m_ApplyInst(BuiltinValueKind::ICMP_EQ, m_SILValue(End),
m_TupleExtractInst(m_Specific(Inc), 0)))) {
DEBUG(llvm::dbgs() << " found no exit condition\n");
return nullptr;
}
// Make sure our end value is loop invariant.
if (!dominates(DT, End, Preheader))
return nullptr;
DEBUG(llvm::dbgs() << " found an induction variable (ICMP_EQ): "
<< *HeaderVal << " start: " << *Start.getDef()
<< " end: " << *End.getDef());
// Check whether the addition is overflow checked by a cond_fail or whether
// code in the preheader's predecessor ensures that we won't overflow.
bool IsRangeChecked = false;
if (!isOverflowChecked(Inc)) {
IsRangeChecked = isRangeChecked(Start, End, Preheader, DT);
if (!IsRangeChecked)
return nullptr;
}
return new (Allocator.Allocate()) InductionInfo(
HeaderVal, Inc, Start, End, BuiltinValueKind::ICMP_EQ, IsRangeChecked);
}
static SILValue getArrayStructPointer(ArrayCallKind K, SILValue Array) {
assert(K != ArrayCallKind::kNone);
if (K < ArrayCallKind::kMakeMutable) {
auto LI = dyn_cast<LoadInst>(Array.getDef());
if (!LI) {
return Array;
}
return LI->getOperand();
}
return Array;
}
/// Copy the array load to the insert point.
static SILValue copyArrayLoad(SILValue ArrayStructValue,
SILInstruction *InsertBefore,
DominanceInfo *DT) {
if (DT->dominates(ArrayStructValue.getDef()->getParentBB(),
InsertBefore->getParent()))
return ArrayStructValue;
auto *LI = cast<LoadInst>(ArrayStructValue.getDef());
// Recursively move struct_element_addr.
auto *Val = LI->getOperand().getDef();
auto *InsertPt = InsertBefore;
while (!DT->dominates(Val->getParentBB(), InsertBefore->getParent())) {
auto *Inst = cast<StructElementAddrInst>(Val);
Inst->moveBefore(InsertPt);
Val = Inst->getOperand().getDef();
InsertPt = Inst;
}
return SILValue(LI->clone(InsertBefore), 0);
}
// Walk backwards in BB looking for the last use of a given
// value, and add it to the set of release points.
static bool addLastUse(SILValue V, SILBasicBlock *BB,
ReleaseTracker &Tracker) {
for (auto I = BB->rbegin(); I != BB->rend(); ++I) {
for (auto &Op : I->getAllOperands())
if (Op.get().getDef() == V.getDef()) {
Tracker.trackLastRelease(&*I);
return true;
}
}
llvm_unreachable("BB is expected to have a use of a closure");
return false;
}
bool swift::mayUseValue(SILInstruction *User, SILValue Ptr,
AliasAnalysis *AA) {
// If Inst is an instruction that we know can never use values with reference
// semantics, return true.
if (canNeverUseValues(User))
return false;
// If the user is a load or a store and we can prove that it does not access
// the object then return true.
// Notice that we need to check all of the values of the object.
if (isa<StoreInst>(User)) {
for (int i = 0, e = Ptr->getNumTypes(); i < e; i++) {
if (AA->mayWriteToMemory(User, SILValue(Ptr.getDef(), i)))
return true;
}
return false;
}
if (isa<LoadInst>(User) ) {
for (int i = 0, e = Ptr->getNumTypes(); i < e; i++) {
if (AA->mayReadFromMemory(User, SILValue(Ptr.getDef(), i)))
return true;
}
return false;
}
// If we have a terminator instruction, see if it can use ptr. This currently
// means that we first show that TI cannot indirectly use Ptr and then use
// alias analysis on the arguments.
if (auto *TI = dyn_cast<TermInst>(User))
return canTerminatorUseValue(TI, Ptr, AA);
// TODO: If we add in alias analysis support here for apply inst, we will need
// to check that the pointer does not escape.
// Otherwise, assume that Inst can use Target.
return true;
}
/// Given an address defined by 'Def', find the object root and all direct uses,
/// not including:
/// - 'Def' itself
/// - Transitive uses of 'Def' (listed elsewhere in DestUserInsts)
///
/// If the returned root is not 'Def' itself, then 'Def' must be an address
/// projection that can be trivially rematerialized with the root as its
/// operand.
static ValueBase *
findAddressRootAndUsers(ValueBase *Def,
SmallPtrSetImpl<SILInstruction*> &RootUserInsts) {
if (isa<InitEnumDataAddrInst>(Def) || isa<InitExistentialAddrInst>(Def)) {
SILValue InitRoot = cast<SILInstruction>(Def)->getOperand(0);
for (auto *Use : InitRoot.getUses()) {
auto *UserInst = Use->getUser();
if (UserInst == Def)
continue;
RootUserInsts.insert(UserInst);
}
return InitRoot.getDef();
}
return Def;
}
SILValue SILValue::stripValueProjections() {
SILValue V = *this;
while (true) {
V = stripSinglePredecessorArgs(V);
switch (V->getKind()) {
case ValueKind::StructExtractInst:
case ValueKind::TupleExtractInst:
V = cast<SILInstruction>(V.getDef())->getOperand(0);
continue;
default:
return V;
}
}
}
SILValue SILValue::stripCasts() {
SILValue V = *this;
while (true) {
V = stripSinglePredecessorArgs(V);
auto K = V->getKind();
if (isRCIdentityPreservingCast(K)
|| K == ValueKind::UncheckedTrivialBitCastInst
|| K == ValueKind::MarkDependenceInst) {
V = cast<SILInstruction>(V.getDef())->getOperand(0);
continue;
}
return V;
}
}
/// Look for checks that guarantee that start is less than or equal to end.
static bool isSignedLessEqual(SILValue Start, SILValue End, SILBasicBlock &BB) {
// If we have an inclusive range "low...up" the loop exit count will be
// "up + 1" but the overflow check is on "up".
SILValue PreInclusiveEnd;
if (!match(
End.getDef(),
m_TupleExtractInst(m_ApplyInst(BuiltinValueKind::SAddOver,
m_SILValue(PreInclusiveEnd), m_One()),
0)))
PreInclusiveEnd = SILValue();
bool IsPreInclusiveEndLEQ = false;
bool IsPreInclusiveEndGTEnd = false;
for (auto &Inst : BB)
if (auto CF = dyn_cast<CondFailInst>(&Inst)) {
// Try to match a cond_fail on "XOR , (SLE Start, End), 1".
if (match(CF->getOperand().getDef(),
m_ApplyInst(BuiltinValueKind::Xor,
m_ApplyInst(BuiltinValueKind::ICMP_SLE,
m_Specific(Start.getDef()),
m_Specific(End.getDef())),
m_One())))
return true;
// Inclusive ranges will have a check on the upper value (before adding
// one).
if (PreInclusiveEnd) {
if (match(CF->getOperand().getDef(),
m_ApplyInst(BuiltinValueKind::Xor,
m_ApplyInst(BuiltinValueKind::ICMP_SLE,
m_Specific(Start.getDef()),
m_Specific(PreInclusiveEnd.getDef())),
m_One())))
IsPreInclusiveEndLEQ = true;
if (match(CF->getOperand().getDef(),
m_ApplyInst(BuiltinValueKind::Xor,
m_ApplyInst(BuiltinValueKind::ICMP_SGT,
m_Specific(End.getDef()),
m_Specific(PreInclusiveEnd.getDef())),
m_One())))
IsPreInclusiveEndGTEnd = true;
if (IsPreInclusiveEndLEQ && IsPreInclusiveEndGTEnd)
return true;
}
}
return false;
}
SILValue SILValue::stripAddressProjections() {
SILValue V = *this;
while (true) {
V = stripSinglePredecessorArgs(V);
switch (V->getKind()) {
case ValueKind::StructElementAddrInst:
case ValueKind::TupleElementAddrInst:
case ValueKind::RefElementAddrInst:
case ValueKind::UncheckedTakeEnumDataAddrInst:
V = cast<SILInstruction>(V.getDef())->getOperand(0);
continue;
default:
return V;
}
}
}
SILValue ConstantTracker::scanProjections(SILValue addr,
SmallVectorImpl<Projection> *Result) {
for (;;) {
if (Projection::isAddrProjection(addr)) {
SILInstruction *I = cast<SILInstruction>(addr.getDef());
if (Result) {
Optional<Projection> P = Projection::addressProjectionForInstruction(I);
Result->push_back(P.getValue());
}
addr = I->getOperand(0);
continue;
}
if (SILValue param = getParam(addr)) {
// Go to the caller.
addr = param;
continue;
}
// Return the base address = the first address which is not a projection.
return addr;
}
}
SILInstruction *optimizeBitOp(BuiltinInst *BI,
CombineFunc combine,
NeutralFunc isNeutral,
ZeroFunc isZero,
SILBuilder &Builder,
SILCombiner *C) {
SILValue firstOp;
APInt bits;
if (!getBitOpArgs(BI, firstOp, bits))
return nullptr;
// Combine all bits of consecutive bit operations, e.g. ((op & c1) & c2) & c3
SILValue op = firstOp;
BuiltinInst *Prev;
APInt prevBits;
while ((Prev = dyn_cast<BuiltinInst>(op)) &&
Prev->getBuiltinInfo().ID == BI->getBuiltinInfo().ID &&
getBitOpArgs(Prev, op, prevBits)) {
combine(bits, prevBits);
}
if (isNeutral(bits))
// The bit operation has no effect, e.g. x | 0 -> x
return C->replaceInstUsesWith(*BI, op.getDef());
if (isZero(bits))
// The bit operation yields to a constant, e.g. x & 0 -> 0
return Builder.createIntegerLiteral(BI->getLoc(), BI->getType(), bits);
if (op != firstOp) {
// We combined multiple bit operations to a single one,
// e.g. (x & c1) & c2 -> x & (c1 & c2)
auto *newLI = Builder.createIntegerLiteral(BI->getLoc(), BI->getType(),
bits);
return Builder.createBuiltin(BI->getLoc(), BI->getName(), BI->getType(),
BI->getSubstitutions(),
{ op, newLI });
}
return nullptr;
}
/// Like ValueIsPHI but also check if the PHI has no source
/// operands, i.e., it was just added.
static SILArgument *ValueIsNewPHI(SILValue Val, SILSSAUpdater *Updater) {
SILArgument *PHI = ValueIsPHI(Val, Updater);
if (PHI) {
auto *PhiBB = PHI->getParent();
size_t PhiIdx = PHI->getIndex();
// If all predecessor edges are 'not set' this is a new phi.
for (auto *PredBB : PhiBB->getPreds()) {
OperandValueArrayRef Edges =
getEdgeValuesForTerminator(PredBB->getTerminator(), PhiBB);
assert(PhiIdx < Edges.size() && "Not enough edges!");
SILValue V = Edges[PhiIdx];
// Check for the 'not set' sentinel.
if (V.getDef() != Updater->PHISentinel.get())
return nullptr;
}
return PHI;
}
return nullptr;
}
/// Compute the subelement number indicated by the specified pointer (which is
/// derived from the root by a series of tuple/struct element addresses) by
/// treating the type as a linearized namespace with sequential elements. For
/// example, given:
///
/// root = alloc { a: { c: i64, d: i64 }, b: (i64, i64) }
/// tmp1 = struct_element_addr root, 1
/// tmp2 = tuple_element_addr tmp1, 0
///
/// This will return a subelement number of 2.
///
/// If this pointer is to within a existential projection, it returns ~0U.
///
static unsigned computeSubelement(SILValue Pointer, SILInstruction *RootInst) {
unsigned SubEltNumber = 0;
SILModule &M = RootInst->getModule();
while (1) {
// If we got to the root, we're done.
if (RootInst == Pointer.getDef())
return SubEltNumber;
auto *Inst = cast<SILInstruction>(Pointer);
if (auto *TEAI = dyn_cast<TupleElementAddrInst>(Inst)) {
SILType TT = TEAI->getOperand().getType();
// Keep track of what subelement is being referenced.
for (unsigned i = 0, e = TEAI->getFieldNo(); i != e; ++i) {
SubEltNumber += getNumSubElements(TT.getTupleElementType(i), M);
}
Pointer = TEAI->getOperand();
} else if (auto *SEAI = dyn_cast<StructElementAddrInst>(Inst)) {
SILType ST = SEAI->getOperand().getType();
// Keep track of what subelement is being referenced.
StructDecl *SD = SEAI->getStructDecl();
for (auto *D : SD->getStoredProperties()) {
if (D == SEAI->getField()) break;
SubEltNumber += getNumSubElements(ST.getFieldType(D, M), M);
}
Pointer = SEAI->getOperand();
} else {
assert((isa<InitExistentialAddrInst>(Inst) || isa<InjectEnumAddrInst>(Inst))&&
"Unknown access path instruction");
// Cannot promote loads and stores from within an existential projection.
return ~0U;
}
}
}
/// Analyse one instruction wrt. the instructions we have seen so far.
void analyseInstruction(SILInstruction *Inst) {
SILValue Array;
ArrayCallKind K;
auto BoundsEffect =
mayChangeArraySize(Inst, K, Array, ReleaseSafeArrayReferences, RCIA);
if (BoundsEffect == ArrayBoundsEffect::kMayChangeAny) {
DEBUG(llvm::dbgs() << " no safe because kMayChangeAny " << *Inst);
allArraysInMemoryAreUnsafe = true;
// No need to store specific arrays in this case.
UnsafeArrays.clear();
return;
}
assert(Array ||
K == ArrayCallKind::kNone &&
"Need to have an array for array semantic functions");
// We need to make sure that the array container is not aliased in ways
// that we don't understand.
if (Array && !isIdentifiedUnderlyingArrayObject(Array)) {
DEBUG(llvm::dbgs()
<< " not safe because of not identified underlying object "
<< *Array.getDef() << " in " << *Inst);
allArraysInMemoryAreUnsafe = true;
// No need to store specific arrays in this case.
UnsafeArrays.clear();
return;
}
if (BoundsEffect == ArrayBoundsEffect::kMayChangeArg) {
UnsafeArrays.insert(Array);
return;
}
assert(BoundsEffect == ArrayBoundsEffect::kNone);
}
/// \brief Removes instructions that create the callee value if they are no
/// longer necessary after inlining.
static void
cleanupCalleeValue(SILValue CalleeValue, ArrayRef<SILValue> CaptureArgs,
ArrayRef<SILValue> FullArgs) {
SmallVector<SILInstruction*, 16> InstsToDelete;
for (SILValue V : FullArgs) {
if (SILInstruction *I = dyn_cast<SILInstruction>(V))
if (I != CalleeValue.getDef() &&
isInstructionTriviallyDead(I))
InstsToDelete.push_back(I);
}
recursivelyDeleteTriviallyDeadInstructions(InstsToDelete, true);
// Handle the case where the callee of the apply is a load instruction.
if (LoadInst *LI = dyn_cast<LoadInst>(CalleeValue)) {
assert(CalleeValue.getResultNumber() == 0);
SILInstruction *ABI = dyn_cast<AllocBoxInst>(LI->getOperand());
assert(ABI && LI->getOperand().getResultNumber() == 1);
// The load instruction must have no more uses left to erase it.
if (!LI->use_empty())
return;
LI->eraseFromParent();
// Look through uses of the alloc box the load is loading from to find up to
// one store and up to one strong release.
StoreInst *SI = nullptr;
StrongReleaseInst *SRI = nullptr;
for (auto UI = ABI->use_begin(), UE = ABI->use_end(); UI != UE; ++UI) {
if (SI == nullptr && isa<StoreInst>(UI.getUser())) {
SI = cast<StoreInst>(UI.getUser());
assert(SI->getDest() == SILValue(ABI, 1));
} else if (SRI == nullptr && isa<StrongReleaseInst>(UI.getUser())) {
SRI = cast<StrongReleaseInst>(UI.getUser());
assert(SRI->getOperand() == SILValue(ABI, 0));
} else
return;
}
// If we found a store, record its source and erase it.
if (SI) {
CalleeValue = SI->getSrc();
SI->eraseFromParent();
} else {
CalleeValue = SILValue();
}
// If we found a strong release, replace it with a strong release of the
// source of the store and erase it.
if (SRI) {
if (CalleeValue.isValid())
SILBuilderWithScope(SRI)
.emitStrongReleaseAndFold(SRI->getLoc(), CalleeValue);
SRI->eraseFromParent();
}
assert(ABI->use_empty());
ABI->eraseFromParent();
if (!CalleeValue.isValid())
return;
}
if (auto *PAI = dyn_cast<PartialApplyInst>(CalleeValue)) {
assert(CalleeValue.getResultNumber() == 0);
SILValue Callee = PAI->getCallee();
if (!tryDeleteDeadClosure(PAI))
return;
CalleeValue = Callee;
}
if (auto *TTTFI = dyn_cast<ThinToThickFunctionInst>(CalleeValue)) {
assert(CalleeValue.getResultNumber() == 0);
SILValue Callee = TTTFI->getCallee();
if (!tryDeleteDeadClosure(TTTFI))
return;
CalleeValue = Callee;
}
if (FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(CalleeValue)) {
assert(CalleeValue.getResultNumber() == 0);
if (!FRI->use_empty())
return;
FRI->eraseFromParent();
}
}
/// \brief Devirtualize an apply of a class method.
///
/// \p AI is the apply to devirtualize.
/// \p ClassOrMetatype is a class value or metatype value that is the
/// self argument of the apply we will devirtualize.
/// return the result value of the new ApplyInst if created one or null.
DevirtualizationResult swift::devirtualizeClassMethod(FullApplySite AI,
SILValue ClassOrMetatype) {
DEBUG(llvm::dbgs() << " Trying to devirtualize : " << *AI.getInstruction());
SILModule &Mod = AI.getModule();
auto *CMI = cast<ClassMethodInst>(AI.getCallee());
auto ClassOrMetatypeType = ClassOrMetatype.getType();
auto *F = getTargetClassMethod(Mod, ClassOrMetatypeType, CMI->getMember());
CanSILFunctionType GenCalleeType = F->getLoweredFunctionType();
auto Subs = getSubstitutionsForCallee(Mod, GenCalleeType,
ClassOrMetatypeType, AI);
CanSILFunctionType SubstCalleeType = GenCalleeType;
if (GenCalleeType->isPolymorphic())
SubstCalleeType = GenCalleeType->substGenericArgs(Mod, Mod.getSwiftModule(), Subs);
SILBuilderWithScope B(AI.getInstruction());
FunctionRefInst *FRI = B.createFunctionRef(AI.getLoc(), F);
// Create the argument list for the new apply, casting when needed
// in order to handle covariant indirect return types and
// contravariant argument types.
llvm::SmallVector<SILValue, 8> NewArgs;
auto Args = AI.getArguments();
auto ParamTypes = SubstCalleeType->getParameterSILTypes();
for (unsigned i = 0, e = Args.size() - 1; i != e; ++i)
NewArgs.push_back(castValueToABICompatibleType(&B, AI.getLoc(), Args[i],
Args[i].getType(),
ParamTypes[i]).getValue());
// Add the self argument, upcasting if required because we're
// calling a base class's method.
auto SelfParamTy = SubstCalleeType->getSelfParameter().getSILType();
NewArgs.push_back(castValueToABICompatibleType(&B, AI.getLoc(),
ClassOrMetatype,
ClassOrMetatypeType,
SelfParamTy).getValue());
// If we have a direct return type, make sure we use the subst callee return
// type. If we have an indirect return type, AI's return type of the empty
// tuple should be ok.
SILType ResultTy = AI.getType();
if (!SubstCalleeType->hasIndirectResult()) {
ResultTy = SubstCalleeType->getSILResult();
}
SILType SubstCalleeSILType =
SILType::getPrimitiveObjectType(SubstCalleeType);
FullApplySite NewAI;
SILBasicBlock *ResultBB = nullptr;
SILBasicBlock *NormalBB = nullptr;
SILValue ResultValue;
bool ResultCastRequired = false;
SmallVector<Operand *, 4> OriginalResultUses;
if (!isa<TryApplyInst>(AI)) {
NewAI = B.createApply(AI.getLoc(), FRI, SubstCalleeSILType, ResultTy,
Subs, NewArgs, cast<ApplyInst>(AI)->isNonThrowing());
ResultValue = SILValue(NewAI.getInstruction(), 0);
} else {
auto *TAI = cast<TryApplyInst>(AI);
// Create new normal and error BBs only if:
// - re-using a BB would create a critical edge
// - or, the result of the new apply would be of different
// type than the argument of the original normal BB.
if (TAI->getNormalBB()->getSinglePredecessor())
ResultBB = TAI->getNormalBB();
else {
ResultBB = B.getFunction().createBasicBlock();
ResultBB->createBBArg(ResultTy);
}
NormalBB = TAI->getNormalBB();
SILBasicBlock *ErrorBB = nullptr;
if (TAI->getErrorBB()->getSinglePredecessor())
ErrorBB = TAI->getErrorBB();
else {
ErrorBB = B.getFunction().createBasicBlock();
ErrorBB->createBBArg(TAI->getErrorBB()->getBBArg(0)->getType());
}
NewAI = B.createTryApply(AI.getLoc(), FRI, SubstCalleeSILType,
Subs, NewArgs,
ResultBB, ErrorBB);
if (ErrorBB != TAI->getErrorBB()) {
B.setInsertionPoint(ErrorBB);
B.createBranch(TAI->getLoc(), TAI->getErrorBB(),
{ErrorBB->getBBArg(0)});
}
// Does the result value need to be casted?
ResultCastRequired = ResultTy != NormalBB->getBBArg(0)->getType();
if (ResultBB != NormalBB)
B.setInsertionPoint(ResultBB);
else if (ResultCastRequired) {
B.setInsertionPoint(NormalBB->begin());
// Collect all uses, before casting.
for (auto *Use : NormalBB->getBBArg(0)->getUses()) {
OriginalResultUses.push_back(Use);
}
NormalBB->getBBArg(0)->replaceAllUsesWith(SILUndef::get(AI.getType(), Mod));
NormalBB->replaceBBArg(0, ResultTy, nullptr);
}
// The result value is passed as a parameter to the normal block.
ResultValue = ResultBB->getBBArg(0);
}
// Check if any casting is required for the return value.
ResultValue = castValueToABICompatibleType(&B, NewAI.getLoc(), ResultValue,
ResultTy, AI.getType()).getValue();
DEBUG(llvm::dbgs() << " SUCCESS: " << F->getName() << "\n");
NumClassDevirt++;
if (NormalBB) {
if (NormalBB != ResultBB) {
// If artificial normal BB was introduced, branch
// to the original normal BB.
B.createBranch(NewAI.getLoc(), NormalBB, { ResultValue });
} else if (ResultCastRequired) {
// Update all original uses by the new value.
for(auto *Use: OriginalResultUses) {
Use->set(ResultValue);
}
}
return std::make_pair(NewAI.getInstruction(), NewAI);
}
// We need to return a pair of values here:
// - the first one is the actual result of the devirtualized call, possibly
// casted into an appropriate type. This SILValue may be a BB arg, if it
// was a cast between optional types.
// - the second one is the new apply site.
return std::make_pair(ResultValue.getDef(), NewAI);
}
/// The main AA entry point. Performs various analyses on V1, V2 in an attempt
/// to disambiguate the two values.
AliasResult AliasAnalysis::aliasInner(SILValue V1, SILValue V2,
SILType TBAAType1,
SILType TBAAType2) {
#ifndef NDEBUG
// If alias analysis is disabled, always return may alias.
if (!shouldRunAA())
return AliasResult::MayAlias;
#endif
// If the two values equal, quickly return must alias.
if (isSameValueOrGlobal(V1, V2))
return AliasResult::MustAlias;
DEBUG(llvm::dbgs() << "ALIAS ANALYSIS:\n V1: " << *V1.getDef()
<< " V2: " << *V2.getDef());
// Pass in both the TBAA types so we can perform typed access TBAA and the
// actual types of V1, V2 so we can perform class based TBAA.
if (!typesMayAlias(TBAAType1, TBAAType2))
return AliasResult::NoAlias;
#ifndef NDEBUG
if (!shouldRunBasicAA())
return AliasResult::MayAlias;
#endif
// Strip off any casts on V1, V2.
V1 = V1.stripCasts();
V2 = V2.stripCasts();
DEBUG(llvm::dbgs() << " After Cast Stripping V1:" << *V1.getDef());
DEBUG(llvm::dbgs() << " After Cast Stripping V2:" << *V2.getDef());
// Ok, we need to actually compute an Alias Analysis result for V1, V2. Begin
// by finding the "base" of V1, V2 by stripping off all casts and GEPs.
SILValue O1 = getUnderlyingObject(V1);
SILValue O2 = getUnderlyingObject(V2);
DEBUG(llvm::dbgs() << " Underlying V1:" << *O1.getDef());
DEBUG(llvm::dbgs() << " Underlying V2:" << *O2.getDef());
// If O1 and O2 do not equal, see if we can prove that they cannot be the
// same object. If we can, return No Alias.
if (O1 != O2 && aliasUnequalObjects(O1, O2))
return AliasResult::NoAlias;
// Ok, either O1, O2 are the same or we could not prove anything based off of
// their inequality.
// Next: ask escape analysis. This catches cases where we compare e.g. a
// non-escaping pointer with another (maybe escaping) pointer. Escape analysis
// uses the connection graph to check if the pointers may point to the same
// content.
// Note that escape analysis must work with the original pointers and not the
// underlying objects because it treats projections differently.
if (!EA->canPointToSameMemory(V1, V2)) {
DEBUG(llvm::dbgs() << " Found not-aliased objects based on"
"escape analysis\n");
return AliasResult::NoAlias;
}
// Now we climb up use-def chains and attempt to do tricks based off of GEPs.
// First if one instruction is a gep and the other is not, canonicalize our
// inputs so that V1 always is the instruction containing the GEP.
if (!NewProjection::isAddressProjection(V1) &&
NewProjection::isAddressProjection(V2)) {
std::swap(V1, V2);
std::swap(O1, O2);
}
// If V1 is an address projection, attempt to use information from the
// aggregate type tree to disambiguate it from V2.
if (NewProjection::isAddressProjection(V1)) {
AliasResult Result = aliasAddressProjection(V1, V2, O1, O2);
if (Result != AliasResult::MayAlias)
return Result;
}
// We could not prove anything. Be conservative and return that V1, V2 may
// alias.
return AliasResult::MayAlias;
}
/// Check if the value \p Value is known to be zero, non-zero or unknown.
IsZeroKind swift::isZeroValue(SILValue Value) {
// Inspect integer literals.
if (auto *L = dyn_cast<IntegerLiteralInst>(Value.getDef())) {
if (!L->getValue())
return IsZeroKind::Zero;
return IsZeroKind::NotZero;
}
// Inspect Structs.
switch (Value.getDef()->getKind()) {
// Bitcast of zero is zero.
case ValueKind::UncheckedTrivialBitCastInst:
// Extracting from a zero class returns a zero.
case ValueKind::StructExtractInst:
return isZeroValue(cast<SILInstruction>(Value.getDef())->getOperand(0));
default:
break;
}
// Inspect casts.
if (auto *BI = dyn_cast<BuiltinInst>(Value.getDef())) {
switch (BI->getBuiltinInfo().ID) {
case BuiltinValueKind::IntToPtr:
case BuiltinValueKind::PtrToInt:
case BuiltinValueKind::ZExt:
return isZeroValue(BI->getArguments()[0]);
case BuiltinValueKind::UDiv:
case BuiltinValueKind::SDiv: {
if (IsZeroKind::Zero == isZeroValue(BI->getArguments()[0]))
return IsZeroKind::Zero;
return IsZeroKind::Unknown;
}
case BuiltinValueKind::Mul:
case BuiltinValueKind::SMulOver:
case BuiltinValueKind::UMulOver: {
IsZeroKind LHS = isZeroValue(BI->getArguments()[0]);
IsZeroKind RHS = isZeroValue(BI->getArguments()[1]);
if (LHS == IsZeroKind::Zero || RHS == IsZeroKind::Zero)
return IsZeroKind::Zero;
return IsZeroKind::Unknown;
}
default:
return IsZeroKind::Unknown;
}
}
// Handle results of XXX_with_overflow arithmetic.
if (auto *T = dyn_cast<TupleExtractInst>(Value.getDef())) {
// Make sure we are extracting the number value and not
// the overflow flag.
if (T->getFieldNo() != 0)
return IsZeroKind::Unknown;
BuiltinInst *BI = dyn_cast<BuiltinInst>(T->getOperand());
if (!BI)
return IsZeroKind::Unknown;
return isZeroValue(BI);
}
//Inspect allocations and pointer literals.
if (isa<StringLiteralInst>(Value.getDef()) ||
isa<AllocationInst>(Value.getDef()) ||
isa<GlobalAddrInst>(Value.getDef()))
return IsZeroKind::NotZero;
return IsZeroKind::Unknown;
}