// Get the aggregate member based on the top of the projection stack.
static SILValue getMember(SILInstruction *inst, ProjectionPath &projStack) {
if (!projStack.empty()) {
const Projection &proj = projStack.back();
return proj.getOperandForAggregate(inst);
}
return SILValue();
}
SILValue ConstantTracker::getStoredValue(SILInstruction *loadInst,
ProjectionPath &projStack) {
SILInstruction *store = links[loadInst];
if (!store && callerTracker)
store = callerTracker->links[loadInst];
if (!store) return SILValue();
assert(isa<LoadInst>(loadInst) || isa<CopyAddrInst>(loadInst));
// Push the address projections of the load onto the stack.
SmallVector<Projection, 4> loadProjections;
scanProjections(loadInst->getOperand(0), &loadProjections);
for (const Projection &proj : loadProjections) {
projStack.push_back(proj);
}
// Pop the address projections of the store from the stack.
SmallVector<Projection, 4> storeProjections;
scanProjections(store->getOperand(1), &storeProjections);
for (auto iter = storeProjections.rbegin(); iter != storeProjections.rend();
++iter) {
const Projection &proj = *iter;
// The corresponding load-projection must match the store-projection.
if (projStack.empty() || projStack.back() != proj)
return SILValue();
projStack.pop_back();
}
if (isa<StoreInst>(store))
return store->getOperand(0);
// The copy_addr instruction is both a load and a store. So we follow the link
// again.
assert(isa<CopyAddrInst>(store));
return getStoredValue(store, projStack);
}