static void checkStaticExclusivity(SILFunction &Fn, PostOrderFunctionInfo *PO,
AccessSummaryAnalysis *ASA) {
// The implementation relies on the following SIL invariants:
// - All incoming edges to a block must have the same in-progress
// accesses. This enables the analysis to not perform a data flow merge
// on incoming edges.
// - Further, for a given address each of the in-progress
// accesses must have begun in the same order on all edges. This ensures
// consistent diagnostics across changes to the exploration of the CFG.
// - On return from a function there are no in-progress accesses. This
// enables a sanity check for lean analysis state at function exit.
// - Each end_access instruction corresponds to exactly one begin access
// instruction. (This is encoded in the EndAccessInst itself)
// - begin_access arguments cannot be basic block arguments.
// This enables the analysis to look back to find the *single* storage
// storage location accessed.
if (Fn.empty())
return;
AccessState State(ASA);
// For each basic block, track the stack of current accesses on
// exit from that block.
llvm::SmallDenseMap<SILBasicBlock *, Optional<StorageMap>, 32>
BlockOutAccesses;
BlockOutAccesses[Fn.getEntryBlock()] = StorageMap();
for (auto *BB : PO->getReversePostOrder()) {
Optional<StorageMap> &BBState = BlockOutAccesses[BB];
// Because we use a reverse post-order traversal, unless this is the entry
// at least one of its predecessors must have been reached. Use the out
// state for that predecessor as our in state. The SIL verifier guarantees
// that all incoming edges must have the same current accesses.
for (auto *Pred : BB->getPredecessorBlocks()) {
auto it = BlockOutAccesses.find(Pred);
if (it == BlockOutAccesses.end())
continue;
const Optional<StorageMap> &PredAccesses = it->getSecond();
if (PredAccesses) {
BBState = PredAccesses;
break;
}
}
// The in-progress accesses for the current program point, represented
// as map from storage locations to the accesses in progress for the
// location.
State.Accesses = BBState.getPointer();
for (auto &I : *BB)
checkForViolationsAtInstruction(I, State);
}
// Now that we've collected violations and suppressed calls, emit
// diagnostics.
for (auto &Violation : State.ConflictingAccesses) {
diagnoseExclusivityViolation(Violation, State.CallsToSwap,
Fn.getASTContext());
}
}
static void checkStaticExclusivity(SILFunction &Fn, PostOrderFunctionInfo *PO,
AccessSummaryAnalysis *ASA) {
// The implementation relies on the following SIL invariants:
// - All incoming edges to a block must have the same in-progress
// accesses. This enables the analysis to not perform a data flow merge
// on incoming edges.
// - Further, for a given address each of the in-progress
// accesses must have begun in the same order on all edges. This ensures
// consistent diagnostics across changes to the exploration of the CFG.
// - On return from a function there are no in-progress accesses. This
// enables a sanity check for lean analysis state at function exit.
// - Each end_access instruction corresponds to exactly one begin access
// instruction. (This is encoded in the EndAccessInst itself)
// - begin_access arguments cannot be basic block arguments.
// This enables the analysis to look back to find the *single* storage
// storage location accessed.
if (Fn.empty())
return;
// Collects calls the Standard Library swap() for Fix-Its.
llvm::SmallVector<ApplyInst *, 8> CallsToSwap;
// Stores the accesses that have been found to conflict. Used to defer
// emitting diagnostics until we can determine whether they should
// be suppressed.
llvm::SmallVector<ConflictingAccess, 4> ConflictingAccesses;
// For each basic block, track the stack of current accesses on
// exit from that block.
llvm::SmallDenseMap<SILBasicBlock *, Optional<StorageMap>, 32>
BlockOutAccesses;
BlockOutAccesses[Fn.getEntryBlock()] = StorageMap();
for (auto *BB : PO->getReversePostOrder()) {
Optional<StorageMap> &BBState = BlockOutAccesses[BB];
// Because we use a reverse post-order traversal, unless this is the entry
// at least one of its predecessors must have been reached. Use the out
// state for that predecessor as our in state. The SIL verifier guarantees
// that all incoming edges must have the same current accesses.
for (auto *Pred : BB->getPredecessorBlocks()) {
auto it = BlockOutAccesses.find(Pred);
if (it == BlockOutAccesses.end())
continue;
const Optional<StorageMap> &PredAccesses = it->getSecond();
if (PredAccesses) {
BBState = PredAccesses;
break;
}
}
// The in-progress accesses for the current program point, represented
// as map from storage locations to the accesses in progress for the
// location.
StorageMap &Accesses = *BBState;
for (auto &I : *BB) {
// Apply transfer functions. Beginning an access
// increments the read or write count for the storage location;
// Ending onr decrements the count.
if (auto *BAI = dyn_cast<BeginAccessInst>(&I)) {
SILAccessKind Kind = BAI->getAccessKind();
const AccessedStorage &Storage = findAccessedStorage(BAI->getSource());
AccessInfo &Info = Accesses[Storage];
const IndexTrieNode *SubPath = ASA->findSubPathAccessed(BAI);
if (auto Conflict = shouldReportAccess(Info, Kind, SubPath)) {
ConflictingAccesses.emplace_back(Storage, *Conflict,
RecordedAccess(BAI, SubPath));
}
Info.beginAccess(BAI, SubPath);
continue;
}
if (auto *EAI = dyn_cast<EndAccessInst>(&I)) {
auto It = Accesses.find(findAccessedStorage(EAI->getSource()));
AccessInfo &Info = It->getSecond();
BeginAccessInst *BAI = EAI->getBeginAccess();
const IndexTrieNode *SubPath = ASA->findSubPathAccessed(BAI);
Info.endAccess(EAI, SubPath);
// If the storage location has no more in-progress accesses, remove
// it to keep the StorageMap lean.
if (!Info.hasAccessesInProgress())
Accesses.erase(It);
continue;
}
if (auto *AI = dyn_cast<ApplyInst>(&I)) {
// Record calls to swap() for potential Fix-Its.
if (isCallToStandardLibrarySwap(AI, Fn.getASTContext()))
CallsToSwap.push_back(AI);
else
checkForViolationsInNoEscapeClosures(Accesses, AI, ASA,
ConflictingAccesses);
continue;
}
if (auto *TAI = dyn_cast<TryApplyInst>(&I)) {
checkForViolationsInNoEscapeClosures(Accesses, TAI, ASA,
ConflictingAccesses);
continue;
}
// Sanity check to make sure entries are properly removed.
assert((!isa<ReturnInst>(&I) || Accesses.size() == 0) &&
"Entries were not properly removed?!");
}
}
// Now that we've collected violations and suppressed calls, emit
// diagnostics.
for (auto &Violation : ConflictingAccesses) {
diagnoseExclusivityViolation(Violation, CallsToSwap, Fn.getASTContext());
}
}
