/// Emit code to release/destroy temporaries.
void PartialApplyCombiner::releaseTemporaries() {
// Insert releases and destroy_addrs as early as possible,
// because we don't want to keep objects alive longer than
// its really needed.
for (auto Op : Tmps) {
auto TmpType = Op->getType().getObjectType();
if (TmpType.isTrivial(PAI->getModule()))
continue;
for (auto *EndPoint : PAFrontier) {
Builder.setInsertionPoint(EndPoint);
if (!TmpType.isAddressOnly(PAI->getModule())) {
auto *Load = Builder.createLoad(PAI->getLoc(), Op);
Builder.createReleaseValue(PAI->getLoc(), Load, Atomicity::Atomic);
} else {
Builder.createDestroyAddr(PAI->getLoc(), Op);
}
}
}
}
/// Emit dealloc_stack for all temporaries.
void PartialApplyCombiner::deallocateTemporaries() {
// Insert dealloc_stack instructions at all function exit points.
for (SILBasicBlock &BB : *PAI->getFunction()) {
TermInst *Term = BB.getTerminator();
if (!Term->isFunctionExiting())
continue;
for (auto Op : Tmps) {
Builder.setInsertionPoint(Term);
Builder.createDeallocStack(PAI->getLoc(), Op);
}
}
}
/// Process an apply instruction which uses a partial_apply
/// as its callee.
/// Returns true on success.
bool PartialApplyCombiner::processSingleApply(FullApplySite AI) {
Builder.setInsertionPoint(AI.getInstruction());
Builder.setCurrentDebugScope(AI.getDebugScope());
// Prepare the args.
SmallVector<SILValue, 8> Args;
// First the ApplyInst args.
for (auto Op : AI.getArguments())
Args.push_back(Op);
SILInstruction *InsertionPoint = &*Builder.getInsertionPoint();
// Next, the partial apply args.
// Pre-process partial_apply arguments only once, lazily.
if (isFirstTime) {
isFirstTime = false;
if (!allocateTemporaries())
return false;
}
// Now, copy over the partial apply args.
for (auto Op : PAI->getArguments()) {
auto Arg = Op;
// If there is new temporary for this argument, use it instead.
if (isa<AllocStackInst>(Arg)) {
if (ArgToTmp.count(Arg)) {
Op = ArgToTmp.lookup(Arg);
}
}
Args.push_back(Op);
}
Builder.setInsertionPoint(InsertionPoint);
Builder.setCurrentDebugScope(AI.getDebugScope());
// The thunk that implements the partial apply calls the closure function
// that expects all arguments to be consumed by the function. However, the
// captured arguments are not arguments of *this* apply, so they are not
// pre-incremented. When we combine the partial_apply and this apply into
// a new apply we need to retain all of the closure non-address type
// arguments.
auto ParamInfo = PAI->getSubstCalleeType()->getParameters();
auto PartialApplyArgs = PAI->getArguments();
// Set of arguments that need to be released after each invocation.
SmallVector<SILValue, 8> ToBeReleasedArgs;
for (unsigned i = 0, e = PartialApplyArgs.size(); i < e; ++i) {
SILValue Arg = PartialApplyArgs[i];
if (!Arg->getType().isAddress()) {
// Retain the argument as the callee may consume it.
Builder.emitRetainValueOperation(PAI->getLoc(), Arg);
// For non consumed parameters (e.g. guaranteed), we also need to
// insert releases after each apply instruction that we create.
if (!ParamInfo[ParamInfo.size() - PartialApplyArgs.size() + i].
isConsumed())
ToBeReleasedArgs.push_back(Arg);
}
}
auto *F = FRI->getReferencedFunction();
SILType FnType = F->getLoweredType();
SILType ResultTy = F->getLoweredFunctionType()->getSILResult();
ArrayRef<Substitution> Subs = PAI->getSubstitutions();
if (!Subs.empty()) {
FnType = FnType.substGenericArgs(PAI->getModule(), Subs);
ResultTy = FnType.getAs<SILFunctionType>()->getSILResult();
}
FullApplySite NAI;
if (auto *TAI = dyn_cast<TryApplyInst>(AI))
NAI =
Builder.createTryApply(AI.getLoc(), FRI, FnType, Subs, Args,
TAI->getNormalBB(), TAI->getErrorBB());
else
NAI =
Builder.createApply(AI.getLoc(), FRI, FnType, ResultTy, Subs, Args,
cast<ApplyInst>(AI)->isNonThrowing());
// We also need to release the partial_apply instruction itself because it
// is consumed by the apply_instruction.
if (auto *TAI = dyn_cast<TryApplyInst>(AI)) {
Builder.setInsertionPoint(TAI->getNormalBB()->begin());
for (auto Arg : ToBeReleasedArgs) {
Builder.emitReleaseValueOperation(PAI->getLoc(), Arg);
}
Builder.createStrongRelease(AI.getLoc(), PAI, Atomicity::Atomic);
Builder.setInsertionPoint(TAI->getErrorBB()->begin());
// Release the non-consumed parameters.
for (auto Arg : ToBeReleasedArgs) {
Builder.emitReleaseValueOperation(PAI->getLoc(), Arg);
}
Builder.createStrongRelease(AI.getLoc(), PAI, Atomicity::Atomic);
Builder.setInsertionPoint(AI.getInstruction());
} else {
// Release the non-consumed parameters.
for (auto Arg : ToBeReleasedArgs) {
Builder.emitReleaseValueOperation(PAI->getLoc(), Arg);
}
Builder.createStrongRelease(AI.getLoc(), PAI, Atomicity::Atomic);
}
SilCombiner->replaceInstUsesWith(*AI.getInstruction(), NAI.getInstruction());
SilCombiner->eraseInstFromFunction(*AI.getInstruction());
return true;
}
/// Returns true on success.
bool PartialApplyCombiner::allocateTemporaries() {
// Copy the original arguments of the partial_apply into
// newly created temporaries and use these temporaries instead of
// the original arguments afterwards.
// This is done to "extend" the life-time of original partial_apply
// arguments, as they may be destroyed/deallocated before the last
// use by one of the apply instructions.
// TODO:
// Copy arguments of the partial_apply into new temporaries
// only if the lifetime of arguments ends before their uses
// by apply instructions.
bool needsReleases = false;
CanSILFunctionType PAITy =
dyn_cast<SILFunctionType>(PAI->getCallee()->getType().getSwiftType());
// Emit a destroy value for each captured closure argument.
ArrayRef<SILParameterInfo> Params = PAITy->getParameters();
auto Args = PAI->getArguments();
unsigned Delta = Params.size() - Args.size();
llvm::SmallVector<std::pair<SILValue, unsigned>, 8> ArgsToHandle;
for (unsigned AI = 0, AE = Args.size(); AI != AE; ++AI) {
SILValue Arg = Args[AI];
SILParameterInfo Param = Params[AI + Delta];
if (Param.isIndirectMutating())
continue;
// Create a temporary and copy the argument into it, if:
// - the argument stems from an alloc_stack
// - the argument is consumed by the callee and is indirect
// (e.g. it is an @in argument)
if (isa<AllocStackInst>(Arg) ||
(Param.isConsumed() && Param.isIndirect())) {
// If the temporary is non-trivial, we need to release it later.
if (!Arg->getType().isTrivial(PAI->getModule()))
needsReleases = true;
ArgsToHandle.push_back(std::make_pair(Arg, AI));
}
}
if (needsReleases) {
// Compute the set of endpoints, which will be used to insert releases of
// temporaries. This may fail if the frontier is located on a critical edge
// which we may not split (no CFG changes in SILCombine).
ValueLifetimeAnalysis VLA(PAI);
if (!VLA.computeFrontier(PAFrontier, ValueLifetimeAnalysis::DontModifyCFG))
return false;
}
for (auto ArgWithIdx : ArgsToHandle) {
SILValue Arg = ArgWithIdx.first;
Builder.setInsertionPoint(PAI->getFunction()->begin()->begin());
// Create a new temporary at the beginning of a function.
auto *Tmp = Builder.createAllocStack(PAI->getLoc(), Arg->getType(),
{/*Constant*/ true, ArgWithIdx.second});
Builder.setInsertionPoint(PAI);
// Copy argument into this temporary.
Builder.createCopyAddr(PAI->getLoc(), Arg, Tmp,
IsTake_t::IsNotTake,
IsInitialization_t::IsInitialization);
Tmps.push_back(Tmp);
ArgToTmp.insert(std::make_pair(Arg, Tmp));
}
return true;
}