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_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 3504d7a..3b23798 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -967,7 +967,15 @@
// 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();
+ // Also, because we use the loaded class references only to compare them, we
+ // don't need to unpoison them.
+ // /* HeapReference<Class> */ ecx = str->klass_
__ movl(ecx, Address(str, class_offset));
+ // if (ecx != /* HeapReference<Class> */ arg->klass_) return false
__ cmpl(ecx, Address(arg, class_offset));
__ j(kNotEqual, &return_false);
}