// Allow casting a struct by value when all elements in toType correspond to
// an element of the same size or larger laid out in the same order in
// fromType. The assumption is that if fromType has larger elements, or
// additional elements, their presence cannot induce a more compact layout of
// the overlapping elements.
//
// struct {A, B} -> A is castable
// struct {A, B, C} -> struct {A, B} is castable
// struct { struct {A, B}, C} -> struct {A, B} is castable
// struct { A, B, C} -> struct { struct {A, B}, C} is NOT castable
static bool canUnsafeCastStruct(SILType fromType, StructDecl *fromStruct,
SILType toType, SILModule &M) {
auto fromRange = fromStruct->getStoredProperties();
if (fromRange.begin() == fromRange.end())
return false;
// Can the first element of fromStruct be cast by value into toType?
SILType fromEltTy = fromType.getFieldType(*fromRange.begin(), M);
if (SILType::canUnsafeCastValue(fromEltTy, toType, M))
return true;
// Otherwise, flatten one level of struct elements on each side.
StructDecl *toStruct = toType.getStructOrBoundGenericStruct();
if (!toStruct)
return false;
auto toRange = toStruct->getStoredProperties();
for (auto toI = toRange.begin(), toE = toRange.end(),
fromI = fromRange.begin(), fromE = fromRange.end();
toI != toE; ++toI, ++fromI) {
if (fromI == fromE)
return false; // fromType is a struct with fewer elements.
SILType fromEltTy = fromType.getFieldType(*fromI, M);
SILType toEltTy = toType.getFieldType(*toI, M);
if (!SILType::canUnsafeCastValue(fromEltTy, toEltTy, M))
return false;
}
// fromType's overlapping elements are compatible.
return true;
}
/// 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 an 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)
return SubEltNumber;
auto *Inst = cast<SILInstruction>(Pointer);
if (auto *PBI = dyn_cast<ProjectBoxInst>(Inst)) {
Pointer = PBI->getOperand();
} else 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;
}
}
}
bool swift::ArraySemanticsCall::replaceByAppendingValues(
SILModule &M, SILFunction *AppendFn, SILFunction *ReserveFn,
const SmallVectorImpl<SILValue> &Vals, SubstitutionMap Subs) {
assert(getKind() == ArrayCallKind::kAppendContentsOf &&
"Must be an append_contentsOf call");
assert(AppendFn && "Must provide an append SILFunction");
// We only handle loadable types.
if (any_of(Vals, [&M](SILValue V) -> bool {
return !V->getType().isLoadable(M);
}))
return false;
CanSILFunctionType AppendFnTy = AppendFn->getLoweredFunctionType();
SILValue ArrRef = SemanticsCall->getArgument(1);
SILBuilderWithScope Builder(SemanticsCall);
auto Loc = SemanticsCall->getLoc();
auto *FnRef = Builder.createFunctionRefFor(Loc, AppendFn);
if (Vals.size() > 1) {
// Create a call to reserveCapacityForAppend() to reserve space for multiple
// elements.
FunctionRefBaseInst *ReserveFnRef =
Builder.createFunctionRefFor(Loc, ReserveFn);
SILFunctionType *ReserveFnTy =
ReserveFnRef->getType().castTo<SILFunctionType>();
assert(ReserveFnTy->getNumParameters() == 2);
StructType *IntType =
ReserveFnTy->getParameters()[0].getType()->castTo<StructType>();
StructDecl *IntDecl = IntType->getDecl();
VarDecl *field = *IntDecl->getStoredProperties().begin();
SILType BuiltinIntTy =SILType::getPrimitiveObjectType(
field->getInterfaceType()->getCanonicalType());
IntegerLiteralInst *CapacityLiteral =
Builder.createIntegerLiteral(Loc, BuiltinIntTy, Vals.size());
StructInst *Capacity = Builder.createStruct(Loc,
SILType::getPrimitiveObjectType(CanType(IntType)), {CapacityLiteral});
Builder.createApply(Loc, ReserveFnRef, Subs, {Capacity, ArrRef}, false);
}
for (SILValue V : Vals) {
auto SubTy = V->getType();
auto &ValLowering = Builder.getModule().getTypeLowering(SubTy);
auto CopiedVal = ValLowering.emitCopyValue(Builder, Loc, V);
auto *AllocStackInst = Builder.createAllocStack(Loc, SubTy);
ValLowering.emitStoreOfCopy(Builder, Loc, CopiedVal, AllocStackInst,
IsInitialization_t::IsInitialization);
SILValue Args[] = {AllocStackInst, ArrRef};
Builder.createApply(Loc, FnRef, Subs, Args, false);
Builder.createDeallocStack(Loc, AllocStackInst);
if (!isConsumedParameter(AppendFnTy->getParameters()[0].getConvention())) {
ValLowering.emitDestroyValue(Builder, Loc, CopiedVal);
}
}
CanSILFunctionType AppendContentsOfFnTy =
SemanticsCall->getReferencedFunction()->getLoweredFunctionType();
if (AppendContentsOfFnTy->getParameters()[0].getConvention() ==
ParameterConvention::Direct_Owned) {
SILValue SrcArray = SemanticsCall->getArgument(0);
Builder.createReleaseValue(SemanticsCall->getLoc(), SrcArray,
Builder.getDefaultAtomicity());
}
removeCall();
return true;
}
