[sanitizer] when recycling deadlock graph nodes, properly recycle edges

llvm-svn: 204233

2 files changed, 51 insertions, 2 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h b/compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
index 637153c90a2..965bd804284 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
@@ -153,6 +153,14 @@ class DeadlockDetector {
     if (!available_nodes_.empty())
       return getAvailableNode(data);
     if (!recycled_nodes_.empty()) {
+      // Printf("recycling: n_edges_ %zd\n", n_edges_);
+      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_);
@@ -233,7 +241,7 @@ class DeadlockDetector {
       if (n_edges_ < ARRAY_SIZE(edges_))
         edges_[n_edges_++] = Edge((u16)added_edges[i], (u16)cur_idx,
                                   dtls->findLockContext(added_edges[i]), stk);
-      // Printf("Edge [%zd]: %u %zd=>%zd\n", i, stk, added_edges[i], cur_idx);
+      // Printf("E%zd: %u %zd=>%zd\n", n_edges_, stk, added_edges[i], cur_idx);
     }
     return n_added_edges;
   }
@@ -256,7 +264,7 @@ class DeadlockDetector {
   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, 0);
+    addEdges(dtls, cur_node, stk);
     onLockAfter(dtls, cur_node, stk);
     return is_reachable;
   }
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_deadlock_detector_test.cc b/compiler-rt/lib/sanitizer_common/tests/sanitizer_deadlock_detector_test.cc
index a11b5a5141a..8f9bb329d6a 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_deadlock_detector_test.cc
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_deadlock_detector_test.cc
@@ -444,3 +444,44 @@ void RunLockContextTest() {
 TEST(DeadlockDetector, LockContextTest) {
   RunLockContextTest<BV2>();
 }
+
+template <class BV>
+void RunRemoveEdgesTest() {
+  ScopedDD<BV> sdd;
+  DeadlockDetector<BV> &d = *sdd.dp;
+  DeadlockDetectorTLS<BV> &dtls = sdd.dtls;
+  vector<uptr> node(BV::kSize);
+  u32 stk_from = 0, stk_to = 0;
+  for (size_t i = 0; i < BV::kSize; i++)
+    node[i] = d.newNode(0);
+
+  for (size_t i = 0; i < BV::kSize; i++)
+    EXPECT_FALSE(d.onLock(&dtls, node[i], i + 1));
+  for (size_t i = 0; i < BV::kSize; i++) {
+    for (uptr j = i + 1; j < BV::kSize; j++) {
+      EXPECT_TRUE(d.findEdge(node[i], node[j], &stk_from, &stk_to));
+      EXPECT_EQ(stk_from, i + 1);
+      EXPECT_EQ(stk_to, j + 1);
+    }
+  }
+  EXPECT_EQ(d.testOnlyGetEpoch(), d.size());
+  // Remove and re-create half of the nodes.
+  for (uptr i = 1; i < BV::kSize; i += 2)
+    d.removeNode(node[i]);
+  for (uptr i = 1; i < BV::kSize; i += 2)
+    node[i] = d.newNode(0);
+  EXPECT_EQ(d.testOnlyGetEpoch(), d.size());
+  // The edges from or to the removed nodes should be gone.
+  for (size_t i = 0; i < BV::kSize; i++) {
+    for (uptr j = i + 1; j < BV::kSize; j++) {
+      if ((i % 2) || (j % 2))
+        EXPECT_FALSE(d.findEdge(node[i], node[j], &stk_from, &stk_to));
+      else
+        EXPECT_TRUE(d.findEdge(node[i], node[j], &stk_from, &stk_to));
+    }
+  }
+}
+
+TEST(DeadlockDetector, RemoveEdgesTest) {
+  RunRemoveEdgesTest<BV1>();
+}