[vm/compiler] Improve CallTargets::CreateAndExpand
It should expand past abstract classes if that allows to merge
two consequtive ranges with the same target into one.
In Dart 2 mode cid ranges are often interrupted by
abstract classes introduced by mixin transformation.
This change allows to expand ranges past those classes and
merge consequtive ranges that have the same target.
Change-Id: Ic0f4fa956d989609bebbe6f8d275491c562aa492
Reviewed-on: https://dart-review.googlesource.com/61929
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
diff --git a/runtime/vm/compiler/backend/il.cc b/runtime/vm/compiler/backend/il.cc
index f773c95..81e98f8 100644
--- a/runtime/vm/compiler/backend/il.cc
+++ b/runtime/vm/compiler/backend/il.cc
@@ -3142,18 +3142,27 @@
}
}
}
+
// Spread class-ids to following classes where a lookup yields the same
// method.
+ const intptr_t max_cid = Isolate::Current()->class_table()->NumCids();
for (int idx = 0; idx < length; idx++) {
int upper_limit_cid =
- (idx == length - 1) ? 1000000000 : targets[idx + 1].cid_start;
+ (idx == length - 1) ? max_cid : targets[idx + 1].cid_start;
const Function& target = *targets.TargetAt(idx)->target;
if (MethodRecognizer::PolymorphicTarget(target)) continue;
+ // The code below makes attempt to avoid spreading class-id range
+ // into a suffix that consists purely of abstract classes to
+ // shorten the range.
+ // However such spreading is beneficial when it allows to
+ // merge to consequtive ranges.
+ intptr_t cid_end_including_abstract = targets[idx].cid_end;
for (int i = targets[idx].cid_end + 1; i < upper_limit_cid; i++) {
bool class_is_abstract = false;
if (FlowGraphCompiler::LookupMethodFor(i, name, args_desc, &fn,
&class_is_abstract) &&
fn.raw() == target.raw()) {
+ cid_end_including_abstract = i;
if (!class_is_abstract) {
targets[idx].cid_end = i;
}
@@ -3161,6 +3170,16 @@
break;
}
}
+
+ // Check if we have a suffix that consists of abstract classes
+ // and expand into it if that would allow us to merge this
+ // range with subsequent range.
+ if ((cid_end_including_abstract > targets[idx].cid_end) &&
+ (idx < length - 1) &&
+ ((cid_end_including_abstract + 1) == targets[idx + 1].cid_start) &&
+ (target.raw() == targets.TargetAt(idx + 1)->target->raw())) {
+ targets[idx].cid_end = cid_end_including_abstract;
+ }
}
targets.MergeIntoRanges();
return &targets;
