Use side vector while sweeping jvmti-weak-table

In the code we were erasing all <K,V> pairs for which object reference
(Key) is changed, and then emplacing the ones which were moved. This
is not compatible with in-place compaction algorithms as then there is a
possibility that a to-space object reference being added to the map is
already there as a from-space reference.

In this CL, we change it to use a side vector to hold all updated <K,V>
until the end of map traversal, and then insert all of them back in the
map.

Bug: 160737021
Test: ART_USE_READ_BARRIER=false art/test/testrunner/testrunner.py
--host --debug -t 905-object-free

Change-Id: Ib416ca0b21d4a9fc44721495b798f82be9387900

1 files changed, 7 insertions, 7 deletions

diff --git a/openjdkjvmti/jvmti_weak_table.h b/openjdkjvmti/jvmti_weak_table.h
index afa2d1da0a..674b2a3d52 100644
--- a/openjdkjvmti/jvmti_weak_table.h
+++ b/openjdkjvmti/jvmti_weak_table.h
@@ -211,13 +211,13 @@ class JvmtiWeakTable : public art::gc::SystemWeakHolder {
   };
 
   using TagAllocator = JvmtiAllocator<std::pair<const art::GcRoot<art::mirror::Object>, T>>;
-  std::unordered_map<art::GcRoot<art::mirror::Object>,
-                     T,
-                     HashGcRoot,
-                     EqGcRoot,
-                     TagAllocator> tagged_objects_
-      GUARDED_BY(allow_disallow_lock_)
-      GUARDED_BY(art::Locks::mutator_lock_);
+  using TagMap = std::unordered_map<art::GcRoot<art::mirror::Object>,
+                                    T,
+                                    HashGcRoot,
+                                    EqGcRoot,
+                                    TagAllocator>;
+
+  TagMap tagged_objects_ GUARDED_BY(allow_disallow_lock_) GUARDED_BY(art::Locks::mutator_lock_);
   // To avoid repeatedly scanning the whole table, remember if we did that since the last sweep.
   bool update_since_last_sweep_;
 };