Check that the String class is not movable in String.equals intrinsics.
Test: art/test.py
Bug: 68181300
Bug: 67628039
Change-Id: I66afa3ea010f758125f8aec79509f0255cb5ea03
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index 7684dc7..fcd2788 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -1464,8 +1464,16 @@
// All string objects must have the same type since String cannot be subclassed.
// Receiver must be a string object, so its class field is equal to all strings' class fields.
// If the argument is a string object, its class field must be equal to receiver's class field.
+ //
+ // As the String class is expected to be non-movable, we can read the class
+ // field from String.equals' arguments without read barriers.
+ AssertNonMovableStringClass();
+ // /* HeapReference<Class> */ temp = str->klass_
__ Ldr(temp, MemOperand(str.X(), class_offset));
+ // /* HeapReference<Class> */ temp1 = arg->klass_
__ Ldr(temp1, MemOperand(arg.X(), class_offset));
+ // Also, because we use the previously loaded class references only in the
+ // following comparison, we don't need to unpoison them.
__ Cmp(temp, temp1);
__ B(&return_false, ne);
}