`AllocArt{Field,Method}Array()` requires mutator lock.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: If11ba77ddcbab62442d18067f4fc9df910f86bb0

1 files changed, 9 insertions, 3 deletions

diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 0fc18335da..406172ca5d 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -540,13 +540,19 @@ class ClassLinker {
       REQUIRES(!Locks::dex_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  // Allocating `ArtField` and `ArtMethod` arrays can lead to adding new arenas to
+  // the `LinearAlloc` but the CMC GC's `CompactionPause()` does not expect new
+  // arenas being concurrently added. Therefore we require these allocations to be
+  // done with the mutator lock held shared as this prevents concurrent execution
+  // with the `CompactionPause()` where we hold the mutator lock exclusively.
   LengthPrefixedArray<ArtField>* AllocArtFieldArray(Thread* self,
                                                     LinearAlloc* allocator,
-                                                    size_t length);
-
+                                                    size_t length)
+      REQUIRES_SHARED(Locks::mutator_lock_);
   LengthPrefixedArray<ArtMethod>* AllocArtMethodArray(Thread* self,
                                                       LinearAlloc* allocator,
-                                                      size_t length);
+                                                      size_t length)
+      REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Convenience AllocClass() overload that uses mirror::Class::InitializeClassVisitor
   // for the class initialization and uses the `java_lang_Class` from class roots