tree ff04c6edd05a1db55aa142a4f823f686db1eb582
parent 8fbaaffd2ef77c4fe10063be1780d70b3831ed22
author Tess Strickland <sstrickl@google.com> 1629397921 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1629397921 +0000

[vm/compiler] Reduce number of subtype comparisons in AOT.

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>