Previously when building subtype class id ranges for a class in AOT, we
looped over the entire class table, even though in most cases, the
number of actual subclasses and implementors of the class is a small
subset of all loaded classes.
Instead, use the same hierarchy information in both JIT and AOT, only
falling back to traversing the entire class table in cases where the
hierarchy information is missing.
Additional changes:
* Do not generate unused type argument checks if the subtype class id
range to check is empty.
* Only generate a nullability check when checking that an instance
type argument is a subtype of non-nullable Object in null safe mode.
* Fix AbstractType::IsSubtypeOf so _Closure <: Function.
Fixes https://github.com/dart-lang/sdk/issues/46936
TEST=vm/cc/HierarchyInfo
Cq-Include-Trybots: luci.dart.try:vm-kernel-linux-release-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-nnbd-linux-release-x64-try,vm-kernel-tsan-linux-release-x64-try,vm-kernel-linux-product-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-linux-release-simarm-try,vm-kernel-linux-release-simarm64-try
Change-Id: Ic0310208d271ef04e778f070f420ae0abbdd47d3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/210581
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Tess Strickland
431ed5183f