[vm] Fix non-reproducibility of VM builds.
We recently removed two kind bits from `Function` to free up space for other
bits. This left two bits in `RawFunction::kind_tag_` unused and no longer
deterministically initialized. This caused `Function` objects saved in the
snapshot within the `.rodata` section of the `dart` binary to be serialized with
a non-deterministic kind tag. We now zero-initialize the kind tag.
# Test Plan
I built the `runtime` target (which includes `dart`) 10 times locally and
received the same SHA256 hash for `dart` each time.
Change-Id: Ib0de4b4b040e26a92a1ba3364460bcec0f665789
Reviewed-on: https://dart-review.googlesource.com/57624
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index bd98c07..7457318 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -7067,6 +7067,7 @@
Heap::Space space) {
ASSERT(!owner.IsNull() || (kind == RawFunction::kSignatureFunction));
const Function& result = Function::Handle(Function::New(space));
+ result.set_kind_tag(0);
result.set_parameter_types(Object::empty_array());
result.set_parameter_names(Object::empty_array());
result.set_name(name);
