SILValue Lowering::emitIsa(SILGenFunction &SGF, SILLocation loc,
Expr *operand, Type targetType,
CheckedCastKind castKind) {
// Handle collection downcasts separately.
if (castKind == CheckedCastKind::ArrayDowncast ||
castKind == CheckedCastKind::DictionaryDowncast ||
castKind == CheckedCastKind::SetDowncast) {
ManagedValue operandMV = SGF.emitRValueAsSingleValue(operand);
ManagedValue optValue = emitCollectionDowncastExpr(
SGF, operandMV, operand->getType(), loc,
targetType,
SGFContext(), /*conditional=*/true)
.getAsSingleValue(SGF, loc);
// Materialize the input.
SILValue optValueTemp;
if (optValue.getType().isAddress()) {
optValueTemp = optValue.forward(SGF);
} else {
optValueTemp = SGF.emitTemporaryAllocation(loc, optValue.getType());
optValue.forwardInto(SGF, loc, optValueTemp);
}
return SGF.emitDoesOptionalHaveValue(loc, optValueTemp);
}
// Prepare a jump destination here.
ExitableFullExpr scope(SGF, CleanupLocation::get(loc));
auto i1Ty = SILType::getBuiltinIntegerType(1, SGF.getASTContext());
SGF.emitCheckedCastBranch(loc, operand, targetType, SGFContext(),
[&](ManagedValue value) {
SILValue yes = SGF.B.createIntegerLiteral(loc, i1Ty, 1);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, yes);
},
[&] {
SILValue no = SGF.B.createIntegerLiteral(loc, i1Ty, 0);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, no);
});
auto contBB = scope.exit();
auto isa = new (SGF.SGM.M) SILArgument(contBB, i1Ty);
return isa;
}
RValue Lowering::emitConditionalCheckedCast(SILGenFunction &SGF,
SILLocation loc,
ManagedValue operand,
Type operandType,
Type optTargetType,
CheckedCastKind castKind,
SGFContext C) {
// Drill into the result type.
CanType resultObjectType =
optTargetType->getCanonicalType().getAnyOptionalObjectType();
assert(resultObjectType);
// Handle collection downcasts directly; they have specific library
// entry points.
if (castKind == CheckedCastKind::ArrayDowncast ||
castKind == CheckedCastKind::DictionaryDowncast ||
castKind == CheckedCastKind::SetDowncast) {
return emitCollectionDowncastExpr(SGF, operand, operandType, loc,
resultObjectType, C,
/*conditional=*/true);
}
operand = adjustForConditionalCheckedCastOperand(loc, operand,
operandType->getCanonicalType(),
resultObjectType, SGF);
auto someDecl = SGF.getASTContext().getOptionalSomeDecl();
auto &resultTL = SGF.getTypeLowering(optTargetType);
// Set up a result buffer if desirable/required.
SILValue resultBuffer;
SILValue resultObjectBuffer;
Optional<TemporaryInitialization> resultObjectTemp;
SGFContext resultObjectCtx;
if (resultTL.isAddressOnly() ||
(C.getEmitInto() && C.getEmitInto()->getAddressOrNull())) {
SILType resultTy = resultTL.getLoweredType();
resultBuffer = SGF.getBufferForExprResult(loc, resultTy, C);
resultObjectBuffer =
SGF.B.createInitEnumDataAddr(loc, resultBuffer, someDecl,
resultTy.getAnyOptionalObjectType().getAddressType());
resultObjectTemp.emplace(resultObjectBuffer, CleanupHandle::invalid());
resultObjectCtx = SGFContext(&resultObjectTemp.getValue());
}
// Prepare a jump destination here.
ExitableFullExpr scope(SGF, CleanupLocation::get(loc));
auto operandCMV = ConsumableManagedValue::forOwned(operand);
SGF.emitCheckedCastBranch(loc, operandCMV, operandType,
resultObjectType, resultObjectCtx,
// The success path.
[&](ManagedValue objectValue) {
// If we're not emitting into a temporary, just wrap up the result
// in Some and go to the continuation block.
if (!resultObjectTemp) {
auto some = SGF.B.createEnum(loc, objectValue.forward(SGF),
someDecl, resultTL.getLoweredType());
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, { some });
return;
}
// Otherwise, make sure the value is in the context.
if (!objectValue.isInContext()) {
objectValue.forwardInto(SGF, loc, resultObjectBuffer);
}
SGF.B.createInjectEnumAddr(loc, resultBuffer, someDecl);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc);
},
// The failure path.
[&] {
auto noneDecl = SGF.getASTContext().getOptionalNoneDecl();
// If we're not emitting into a temporary, just wrap up the result
// in None and go to the continuation block.
if (!resultObjectTemp) {
auto none =
SGF.B.createEnum(loc, nullptr, noneDecl, resultTL.getLoweredType());
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, { none });
// Just construct the enum directly in the context.
} else {
SGF.B.createInjectEnumAddr(loc, resultBuffer, noneDecl);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc);
}
});
// Enter the continuation block.
auto contBB = scope.exit();
ManagedValue result;
if (resultObjectTemp) {
result = SGF.manageBufferForExprResult(resultBuffer, resultTL, C);
} else {
auto argument =
new (SGF.F.getModule()) SILArgument(contBB, resultTL.getLoweredType());
result = SGF.emitManagedRValueWithCleanup(argument, resultTL);
}
return RValue(SGF, loc, optTargetType->getCanonicalType(), result);
}
