/// Emit a materializeForSet operation that simply loads the l-value
/// into the result buffer. This operation creates a callback to write
/// the l-value back.
SILValue
MaterializeForSetEmitter::emitUsingGetterSetter(SILGenFunction &gen,
SILLocation loc,
ManagedValue self,
RValue &&indices,
SILValue resultBuffer,
SILValue callbackBuffer,
SILFunction *&callback) {
// Copy the indices into the callback storage.
const TypeLowering *indicesTL = nullptr;
CleanupHandle indicesCleanup = CleanupHandle::invalid();
CanType indicesFormalType;
if (isa<SubscriptDecl>(WitnessStorage)) {
indicesFormalType = indices.getType();
indicesTL = &gen.getTypeLowering(indicesFormalType);
SILValue allocatedCallbackBuffer =
gen.B.createAllocValueBuffer(loc, indicesTL->getLoweredType(),
callbackBuffer);
// Emit into the buffer.
auto init = gen.useBufferAsTemporary(loc, allocatedCallbackBuffer,
*indicesTL);
indicesCleanup = init->getInitializedCleanup();
indices.copyInto(gen, init.get(), loc);
}
// Set up the result buffer.
resultBuffer =
gen.B.createPointerToAddress(loc, resultBuffer,
Conformance
? RequirementStorageType.getAddressType()
: WitnessStorageType.getAddressType());
TemporaryInitialization init(resultBuffer, CleanupHandle::invalid());
// Evaluate the getter into the result buffer.
LValue lv = buildLValue(gen, loc, self, std::move(indices), AccessKind::Read);
ManagedValue result = gen.emitLoadOfLValue(loc, std::move(lv),
SGFContext(&init));
if (!result.isInContext()) {
result.forwardInto(gen, loc, resultBuffer);
}
// Forward the cleanup on the saved indices.
if (indicesCleanup.isValid()) {
gen.Cleanups.setCleanupState(indicesCleanup, CleanupState::Dead);
}
callback = createSetterCallback(gen.F, indicesTL, indicesFormalType);
return resultBuffer;
}
