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authornkozlovskiy <nmk@ydb.tech>2023-10-11 19:11:46 +0300
committernkozlovskiy <nmk@ydb.tech>2023-10-11 19:33:28 +0300
commit61b3971447e473726d6cdb23fc298e457b4d973c (patch)
treee2a2a864bb7717f7ae6138f6a3194a254dd2c7bb /contrib/libs/clang14-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
parenta674dc57d88d43c2e8e90a6084d5d2c988e0402c (diff)
downloadydb-61b3971447e473726d6cdb23fc298e457b4d973c.tar.gz
add sanitizers dependencies
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diff --git a/contrib/libs/clang14-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h b/contrib/libs/clang14-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
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+//===-- sanitizer_deadlock_detector.h ---------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of Sanitizer runtime.
+// The deadlock detector maintains a directed graph of lock acquisitions.
+// When a lock event happens, the detector checks if the locks already held by
+// the current thread are reachable from the newly acquired lock.
+//
+// The detector can handle only a fixed amount of simultaneously live locks
+// (a lock is alive if it has been locked at least once and has not been
+// destroyed). When the maximal number of locks is reached the entire graph
+// is flushed and the new lock epoch is started. The node ids from the old
+// epochs can not be used with any of the detector methods except for
+// nodeBelongsToCurrentEpoch().
+//
+// FIXME: this is work in progress, nothing really works yet.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_DEADLOCK_DETECTOR_H
+#define SANITIZER_DEADLOCK_DETECTOR_H
+
+#include "sanitizer_bvgraph.h"
+#include "sanitizer_common.h"
+
+namespace __sanitizer {
+
+// Thread-local state for DeadlockDetector.
+// It contains the locks currently held by the owning thread.
+template <class BV>
+class DeadlockDetectorTLS {
+ public:
+ // No CTOR.
+ void clear() {
+ bv_.clear();
+ epoch_ = 0;
+ n_recursive_locks = 0;
+ n_all_locks_ = 0;
+ }
+
+ bool empty() const { return bv_.empty(); }
+
+ void ensureCurrentEpoch(uptr current_epoch) {
+ if (epoch_ == current_epoch) return;
+ bv_.clear();
+ epoch_ = current_epoch;
+ n_recursive_locks = 0;
+ n_all_locks_ = 0;
+ }
+
+ uptr getEpoch() const { return epoch_; }
+
+ // Returns true if this is the first (non-recursive) acquisition of this lock.
+ bool addLock(uptr lock_id, uptr current_epoch, u32 stk) {
+ CHECK_EQ(epoch_, current_epoch);
+ if (!bv_.setBit(lock_id)) {
+ // The lock is already held by this thread, it must be recursive.
+ CHECK_LT(n_recursive_locks, ARRAY_SIZE(recursive_locks));
+ recursive_locks[n_recursive_locks++] = lock_id;
+ return false;
+ }
+ CHECK_LT(n_all_locks_, ARRAY_SIZE(all_locks_with_contexts_));
+ // lock_id < BV::kSize, can cast to a smaller int.
+ u32 lock_id_short = static_cast<u32>(lock_id);
+ LockWithContext l = {lock_id_short, stk};
+ all_locks_with_contexts_[n_all_locks_++] = l;
+ return true;
+ }
+
+ void removeLock(uptr lock_id) {
+ if (n_recursive_locks) {
+ for (sptr i = n_recursive_locks - 1; i >= 0; i--) {
+ if (recursive_locks[i] == lock_id) {
+ n_recursive_locks--;
+ Swap(recursive_locks[i], recursive_locks[n_recursive_locks]);
+ return;
+ }
+ }
+ }
+ if (!bv_.clearBit(lock_id))
+ return; // probably addLock happened before flush
+ if (n_all_locks_) {
+ for (sptr i = n_all_locks_ - 1; i >= 0; i--) {
+ if (all_locks_with_contexts_[i].lock == static_cast<u32>(lock_id)) {
+ Swap(all_locks_with_contexts_[i],
+ all_locks_with_contexts_[n_all_locks_ - 1]);
+ n_all_locks_--;
+ break;
+ }
+ }
+ }
+ }
+
+ u32 findLockContext(uptr lock_id) {
+ for (uptr i = 0; i < n_all_locks_; i++)
+ if (all_locks_with_contexts_[i].lock == static_cast<u32>(lock_id))
+ return all_locks_with_contexts_[i].stk;
+ return 0;
+ }
+
+ const BV &getLocks(uptr current_epoch) const {
+ CHECK_EQ(epoch_, current_epoch);
+ return bv_;
+ }
+
+ uptr getNumLocks() const { return n_all_locks_; }
+ uptr getLock(uptr idx) const { return all_locks_with_contexts_[idx].lock; }
+
+ private:
+ BV bv_;
+ uptr epoch_;
+ uptr recursive_locks[64];
+ uptr n_recursive_locks;
+ struct LockWithContext {
+ u32 lock;
+ u32 stk;
+ };
+ LockWithContext all_locks_with_contexts_[64];
+ uptr n_all_locks_;
+};
+
+// DeadlockDetector.
+// For deadlock detection to work we need one global DeadlockDetector object
+// and one DeadlockDetectorTLS object per evey thread.
+// This class is not thread safe, all concurrent accesses should be guarded
+// by an external lock.
+// Most of the methods of this class are not thread-safe (i.e. should
+// be protected by an external lock) unless explicitly told otherwise.
+template <class BV>
+class DeadlockDetector {
+ public:
+ typedef BV BitVector;
+
+ uptr size() const { return g_.size(); }
+
+ // No CTOR.
+ void clear() {
+ current_epoch_ = 0;
+ available_nodes_.clear();
+ recycled_nodes_.clear();
+ g_.clear();
+ n_edges_ = 0;
+ }
+
+ // Allocate new deadlock detector node.
+ // If we are out of available nodes first try to recycle some.
+ // If there is nothing to recycle, flush the graph and increment the epoch.
+ // Associate 'data' (opaque user's object) with the new node.
+ uptr newNode(uptr data) {
+ if (!available_nodes_.empty())
+ return getAvailableNode(data);
+ if (!recycled_nodes_.empty()) {
+ for (sptr i = n_edges_ - 1; i >= 0; i--) {
+ if (recycled_nodes_.getBit(edges_[i].from) ||
+ recycled_nodes_.getBit(edges_[i].to)) {
+ Swap(edges_[i], edges_[n_edges_ - 1]);
+ n_edges_--;
+ }
+ }
+ CHECK(available_nodes_.empty());
+ // removeEdgesFrom was called in removeNode.
+ g_.removeEdgesTo(recycled_nodes_);
+ available_nodes_.setUnion(recycled_nodes_);
+ recycled_nodes_.clear();
+ return getAvailableNode(data);
+ }
+ // We are out of vacant nodes. Flush and increment the current_epoch_.
+ current_epoch_ += size();
+ recycled_nodes_.clear();
+ available_nodes_.setAll();
+ g_.clear();
+ n_edges_ = 0;
+ return getAvailableNode(data);
+ }
+
+ // Get data associated with the node created by newNode().
+ uptr getData(uptr node) const { return data_[nodeToIndex(node)]; }
+
+ bool nodeBelongsToCurrentEpoch(uptr node) {
+ return node && (node / size() * size()) == current_epoch_;
+ }
+
+ void removeNode(uptr node) {
+ uptr idx = nodeToIndex(node);
+ CHECK(!available_nodes_.getBit(idx));
+ CHECK(recycled_nodes_.setBit(idx));
+ g_.removeEdgesFrom(idx);
+ }
+
+ void ensureCurrentEpoch(DeadlockDetectorTLS<BV> *dtls) {
+ dtls->ensureCurrentEpoch(current_epoch_);
+ }
+
+ // Returns true if there is a cycle in the graph after this lock event.
+ // Ideally should be called before the lock is acquired so that we can
+ // report a deadlock before a real deadlock happens.
+ bool onLockBefore(DeadlockDetectorTLS<BV> *dtls, uptr cur_node) {
+ ensureCurrentEpoch(dtls);
+ uptr cur_idx = nodeToIndex(cur_node);
+ return g_.isReachable(cur_idx, dtls->getLocks(current_epoch_));
+ }
+
+ u32 findLockContext(DeadlockDetectorTLS<BV> *dtls, uptr node) {
+ return dtls->findLockContext(nodeToIndex(node));
+ }
+
+ // Add cur_node to the set of locks held currently by dtls.
+ void onLockAfter(DeadlockDetectorTLS<BV> *dtls, uptr cur_node, u32 stk = 0) {
+ ensureCurrentEpoch(dtls);
+ uptr cur_idx = nodeToIndex(cur_node);
+ dtls->addLock(cur_idx, current_epoch_, stk);
+ }
+
+ // Experimental *racy* fast path function.
+ // Returns true if all edges from the currently held locks to cur_node exist.
+ bool hasAllEdges(DeadlockDetectorTLS<BV> *dtls, uptr cur_node) {
+ uptr local_epoch = dtls->getEpoch();
+ // Read from current_epoch_ is racy.
+ if (cur_node && local_epoch == current_epoch_ &&
+ local_epoch == nodeToEpoch(cur_node)) {
+ uptr cur_idx = nodeToIndexUnchecked(cur_node);
+ for (uptr i = 0, n = dtls->getNumLocks(); i < n; i++) {
+ if (!g_.hasEdge(dtls->getLock(i), cur_idx))
+ return false;
+ }
+ return true;
+ }
+ return false;
+ }
+
+ // Adds edges from currently held locks to cur_node,
+ // returns the number of added edges, and puts the sources of added edges
+ // into added_edges[].
+ // Should be called before onLockAfter.
+ uptr addEdges(DeadlockDetectorTLS<BV> *dtls, uptr cur_node, u32 stk,
+ int unique_tid) {
+ ensureCurrentEpoch(dtls);
+ uptr cur_idx = nodeToIndex(cur_node);
+ uptr added_edges[40];
+ uptr n_added_edges = g_.addEdges(dtls->getLocks(current_epoch_), cur_idx,
+ added_edges, ARRAY_SIZE(added_edges));
+ for (uptr i = 0; i < n_added_edges; i++) {
+ if (n_edges_ < ARRAY_SIZE(edges_)) {
+ Edge e = {(u16)added_edges[i], (u16)cur_idx,
+ dtls->findLockContext(added_edges[i]), stk,
+ unique_tid};
+ edges_[n_edges_++] = e;
+ }
+ }
+ return n_added_edges;
+ }
+
+ bool findEdge(uptr from_node, uptr to_node, u32 *stk_from, u32 *stk_to,
+ int *unique_tid) {
+ uptr from_idx = nodeToIndex(from_node);
+ uptr to_idx = nodeToIndex(to_node);
+ for (uptr i = 0; i < n_edges_; i++) {
+ if (edges_[i].from == from_idx && edges_[i].to == to_idx) {
+ *stk_from = edges_[i].stk_from;
+ *stk_to = edges_[i].stk_to;
+ *unique_tid = edges_[i].unique_tid;
+ return true;
+ }
+ }
+ return false;
+ }
+
+ // Test-only function. Handles the before/after lock events,
+ // returns true if there is a cycle.
+ bool onLock(DeadlockDetectorTLS<BV> *dtls, uptr cur_node, u32 stk = 0) {
+ ensureCurrentEpoch(dtls);
+ bool is_reachable = !isHeld(dtls, cur_node) && onLockBefore(dtls, cur_node);
+ addEdges(dtls, cur_node, stk, 0);
+ onLockAfter(dtls, cur_node, stk);
+ return is_reachable;
+ }
+
+ // Handles the try_lock event, returns false.
+ // When a try_lock event happens (i.e. a try_lock call succeeds) we need
+ // to add this lock to the currently held locks, but we should not try to
+ // change the lock graph or to detect a cycle. We may want to investigate
+ // whether a more aggressive strategy is possible for try_lock.
+ bool onTryLock(DeadlockDetectorTLS<BV> *dtls, uptr cur_node, u32 stk = 0) {
+ ensureCurrentEpoch(dtls);
+ uptr cur_idx = nodeToIndex(cur_node);
+ dtls->addLock(cur_idx, current_epoch_, stk);
+ return false;
+ }
+
+ // Returns true iff dtls is empty (no locks are currently held) and we can
+ // add the node to the currently held locks w/o changing the global state.
+ // This operation is thread-safe as it only touches the dtls.
+ bool onFirstLock(DeadlockDetectorTLS<BV> *dtls, uptr node, u32 stk = 0) {
+ if (!dtls->empty()) return false;
+ if (dtls->getEpoch() && dtls->getEpoch() == nodeToEpoch(node)) {
+ dtls->addLock(nodeToIndexUnchecked(node), nodeToEpoch(node), stk);
+ return true;
+ }
+ return false;
+ }
+
+ // Finds a path between the lock 'cur_node' (currently not held in dtls)
+ // and some currently held lock, returns the length of the path
+ // or 0 on failure.
+ uptr findPathToLock(DeadlockDetectorTLS<BV> *dtls, uptr cur_node, uptr *path,
+ uptr path_size) {
+ tmp_bv_.copyFrom(dtls->getLocks(current_epoch_));
+ uptr idx = nodeToIndex(cur_node);
+ CHECK(!tmp_bv_.getBit(idx));
+ uptr res = g_.findShortestPath(idx, tmp_bv_, path, path_size);
+ for (uptr i = 0; i < res; i++)
+ path[i] = indexToNode(path[i]);
+ if (res)
+ CHECK_EQ(path[0], cur_node);
+ return res;
+ }
+
+ // Handle the unlock event.
+ // This operation is thread-safe as it only touches the dtls.
+ void onUnlock(DeadlockDetectorTLS<BV> *dtls, uptr node) {
+ if (dtls->getEpoch() == nodeToEpoch(node))
+ dtls->removeLock(nodeToIndexUnchecked(node));
+ }
+
+ // Tries to handle the lock event w/o writing to global state.
+ // Returns true on success.
+ // This operation is thread-safe as it only touches the dtls
+ // (modulo racy nature of hasAllEdges).
+ bool onLockFast(DeadlockDetectorTLS<BV> *dtls, uptr node, u32 stk = 0) {
+ if (hasAllEdges(dtls, node)) {
+ dtls->addLock(nodeToIndexUnchecked(node), nodeToEpoch(node), stk);
+ return true;
+ }
+ return false;
+ }
+
+ bool isHeld(DeadlockDetectorTLS<BV> *dtls, uptr node) const {
+ return dtls->getLocks(current_epoch_).getBit(nodeToIndex(node));
+ }
+
+ uptr testOnlyGetEpoch() const { return current_epoch_; }
+ bool testOnlyHasEdge(uptr l1, uptr l2) {
+ return g_.hasEdge(nodeToIndex(l1), nodeToIndex(l2));
+ }
+ // idx1 and idx2 are raw indices to g_, not lock IDs.
+ bool testOnlyHasEdgeRaw(uptr idx1, uptr idx2) {
+ return g_.hasEdge(idx1, idx2);
+ }
+
+ void Print() {
+ for (uptr from = 0; from < size(); from++)
+ for (uptr to = 0; to < size(); to++)
+ if (g_.hasEdge(from, to))
+ Printf(" %zx => %zx\n", from, to);
+ }
+
+ private:
+ void check_idx(uptr idx) const { CHECK_LT(idx, size()); }
+
+ void check_node(uptr node) const {
+ CHECK_GE(node, size());
+ CHECK_EQ(current_epoch_, nodeToEpoch(node));
+ }
+
+ uptr indexToNode(uptr idx) const {
+ check_idx(idx);
+ return idx + current_epoch_;
+ }
+
+ uptr nodeToIndexUnchecked(uptr node) const { return node % size(); }
+
+ uptr nodeToIndex(uptr node) const {
+ check_node(node);
+ return nodeToIndexUnchecked(node);
+ }
+
+ uptr nodeToEpoch(uptr node) const { return node / size() * size(); }
+
+ uptr getAvailableNode(uptr data) {
+ uptr idx = available_nodes_.getAndClearFirstOne();
+ data_[idx] = data;
+ return indexToNode(idx);
+ }
+
+ struct Edge {
+ u16 from;
+ u16 to;
+ u32 stk_from;
+ u32 stk_to;
+ int unique_tid;
+ };
+
+ uptr current_epoch_;
+ BV available_nodes_;
+ BV recycled_nodes_;
+ BV tmp_bv_;
+ BVGraph<BV> g_;
+ uptr data_[BV::kSize];
+ Edge edges_[BV::kSize * 32];
+ uptr n_edges_;
+};
+
+} // namespace __sanitizer
+
+#endif // SANITIZER_DEADLOCK_DETECTOR_H