/// Transform AccessedStorage from a callee into the caller context. If this is
/// uniquely identified local storage, then return an invalid storage object.
///
/// For correctness, AccessEnforcementOpts relies on all Argument access to
/// either be mapped into the caller's context or marked as an unidentified
/// access at the call site.
///
/// Note: This does *not* map the storage index into the caller function's index
/// range. (When the storage value doesn't need to be remapped, it returns the
/// original storage value.) It's simpler to set the storage index later when it
/// is actually added to the function's storageAccessSet.
static StorageAccessInfo
transformCalleeStorage(const StorageAccessInfo &storage,
FullApplySite fullApply) {
switch (storage.getKind()) {
case AccessedStorage::Box:
case AccessedStorage::Stack:
// Do not merge local storage.
return StorageAccessInfo(AccessedStorage(), storage);
case AccessedStorage::Global:
// Global accesses is universal.
return storage;
case AccessedStorage::Class: {
// If the object's value is an argument, translate it into a value on the
// caller side.
SILValue obj = storage.getObjectProjection().getObject();
if (auto *arg = dyn_cast<SILFunctionArgument>(obj)) {
SILValue argVal = getCallerArg(fullApply, arg->getIndex());
if (argVal) {
auto &proj = storage.getObjectProjection().getProjection();
// Remap the argument source value and inherit the old storage info.
return StorageAccessInfo(AccessedStorage(argVal, proj), storage);
}
}
// Otherwise, continue to reference the value in the callee because we don't
// have any better placeholder for a callee-defined object.
return storage;
}
case AccessedStorage::Argument: {
// Transitively search for the storage base in the caller.
SILValue argVal = getCallerArg(fullApply, storage.getParamIndex());
if (argVal) {
// Remap the argument source value and inherit the old storage info.
auto calleeStorage = findAccessedStorageNonNested(argVal);
if (calleeStorage)
return StorageAccessInfo(calleeStorage, storage);
}
// If the argument can't be transformed, demote it to an unidentified
// access.
return StorageAccessInfo(
AccessedStorage(storage.getValue(), AccessedStorage::Unidentified),
storage);
}
case AccessedStorage::Nested:
llvm_unreachable("Unexpected nested access");
case AccessedStorage::Yield:
// Continue to hold on to yields from the callee because we don't have
// any better placeholder in the callee.
return storage;
case AccessedStorage::Unidentified:
// For unidentified storage, continue to reference the value in the callee
// because we don't have any better placeholder for a callee-defined object.
return storage;
}
}
bool StorageAccessInfo::mergeFrom(const StorageAccessInfo &RHS) {
bool changed = false;
SILAccessKind accessKind = getAccessKind();
assert(accessKind == SILAccessKind::Read
|| accessKind == SILAccessKind::Modify && "uninitialized info");
if (updateAccessKind(accessKind, RHS.getAccessKind())) {
setAccessKind(accessKind);
changed = true;
}
if (hasNoNestedConflict() && !RHS.hasNoNestedConflict()) {
setNoNestedConflict(false);
changed = true;
}
return changed;
}
/// Transform AccessedStorage from a callee into the caller context. If this is
/// uniquely identified local storage, then return an invalid storage object.
///
/// For correctness, AccessEnforcementOpts relies on all Argument access to
/// either be mapped into the caller's context or marked as an unidentified
/// access at the call site.
///
/// Note: This does *not* map the storage index into the caller function's index
/// range. (When the storage value doesn't need to be remapped, it returns the
/// original storage value.) It's simpler to set the storage index later when it
/// is actually added to the function's storageAccessSet.
static StorageAccessInfo
transformCalleeStorage(const StorageAccessInfo &storage,
FullApplySite fullApply) {
switch (storage.getKind()) {
case AccessedStorage::Box:
case AccessedStorage::Stack:
// Do not merge local storage.
return StorageAccessInfo(AccessedStorage(), storage);
case AccessedStorage::Global:
// Global accesses is universal.
return storage;
case AccessedStorage::Class: {
// If the object's value is an argument, translate it into a value on the
// caller side.
SILValue obj = storage.getObjectProjection().getObject();
if (auto *arg = dyn_cast<SILFunctionArgument>(obj)) {
SILValue argVal = getCallerArg(fullApply, arg->getIndex());
if (argVal) {
auto *instr = storage.getObjectProjection().getInstr();
// Remap the argument source value and inherit the old storage info.
return StorageAccessInfo(AccessedStorage(argVal, instr), storage);
}
}
// Otherwise, continue to reference the value in the callee because we don't
// have any better placeholder for a callee-defined object.
return storage;
}
case AccessedStorage::Argument: {
// Transitively search for the storage base in the caller.
SILValue argVal = getCallerArg(fullApply, storage.getParamIndex());
if (argVal) {
// Remap the argument source value and inherit the old storage info.
auto calleeStorage = findAccessedStorageNonNested(argVal);
if (calleeStorage)
return StorageAccessInfo(calleeStorage, storage);
}
// If the argument can't be transformed, demote it to an unidentified
// access.
//
// This is an untested bailout. It is only reachable if the call graph
// contains an edge that getCallerArg is unable to analyze OR if
// findAccessedStorageNonNested returns an invalid SILValue, which won't
// pass SIL verification.
//
// FIXME: In case argVal is invalid, support Unidentified access for invalid
// values. This would also be useful for partially invalidating results.
return StorageAccessInfo(
AccessedStorage(argVal, AccessedStorage::Unidentified), storage);
}
case AccessedStorage::Nested:
llvm_unreachable("Unexpected nested access");
case AccessedStorage::Yield:
// Continue to hold on to yields from the callee because we don't have
// any better placeholder in the callee.
return storage;
case AccessedStorage::Unidentified:
// For unidentified storage, continue to reference the value in the callee
// because we don't have any better placeholder for a callee-defined object.
return storage;
}
llvm_unreachable("unhandled kind");
}
