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[cleanup] Clean kFullTransitionArray path in TransitionsAccessor::Insert

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There is a case where a TransitionArray shrinks during insertion. If
that's the case, we need to compute the index to insert again. However,
we can use the knowledge that already didn't appear in the array, and
after shrinking it shouldn't appear.

Change-Id: I3a742c5d37659064f143db1c4f345b0df35d0d42
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2238029
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68462}
This commit is contained in:
Santiago Aboy Solanes 2020-06-22 10:48:00 +01:00 committed by Commit Bot
parent 6a546bd967
commit 0da6b2cbfe
1 changed files with 15 additions and 19 deletions
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34
src/objects/transitions.cc
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@ -105,7 +105,6 @@ void TransitionsAccessor::Insert(Handle<Name> name, Handle<Map> target,
DisallowHeapAllocation no_gc;
TransitionArray array = transitions();
number_of_transitions = array.number_of_transitions();
new_nof = number_of_transitions;
int index = is_special_transition
? array.SearchSpecial(Symbol::cast(*name), &insertion_index)
@ -117,19 +116,20 @@ void TransitionsAccessor::Insert(Handle<Name> name, Handle<Map> target,
return;
}
++new_nof;
new_nof = number_of_transitions + 1;
CHECK_LE(new_nof, kMaxNumberOfTransitions);
DCHECK(insertion_index >= 0 && insertion_index <= number_of_transitions);
DCHECK_GE(insertion_index, 0);
DCHECK_LE(insertion_index, number_of_transitions);
// If there is enough capacity, insert new entry into the existing array.
if (new_nof <= array.Capacity()) {
array.SetNumberOfTransitions(new_nof);
for (index = number_of_transitions; index > insertion_index; --index) {
array.SetKey(index, array.GetKey(index - 1));
array.SetRawTarget(index, array.GetRawTarget(index - 1));
for (int i = number_of_transitions; i > insertion_index; --i) {
array.SetKey(i, array.GetKey(i - 1));
array.SetRawTarget(i, array.GetRawTarget(i - 1));
}
array.SetKey(index, *name);
array.SetRawTarget(index, HeapObjectReference::Weak(*target));
array.SetKey(insertion_index, *name);
array.SetRawTarget(insertion_index, HeapObjectReference::Weak(*target));
SLOW_DCHECK(array.IsSortedNoDuplicates());
return;
}
@ -147,23 +147,19 @@ void TransitionsAccessor::Insert(Handle<Name> name, Handle<Map> target,
DisallowHeapAllocation no_gc;
TransitionArray array = transitions();
if (array.number_of_transitions() != number_of_transitions) {
DCHECK(array.number_of_transitions() < number_of_transitions);
DCHECK_LT(array.number_of_transitions(), number_of_transitions);
number_of_transitions = array.number_of_transitions();
new_nof = number_of_transitions;
insertion_index = kNotFound;
int index = is_special_transition
? array.SearchSpecial(Symbol::cast(*name), &insertion_index)
: array.Search(details.kind(), *name, details.attributes(),
&insertion_index);
if (index == kNotFound) {
++new_nof;
} else {
insertion_index = index;
}
DCHECK(insertion_index >= 0 && insertion_index <= number_of_transitions);
CHECK_EQ(index, kNotFound);
USE(index);
DCHECK_GE(insertion_index, 0);
DCHECK_LE(insertion_index, number_of_transitions);
number_of_transitions = array.number_of_transitions();
new_nof = number_of_transitions + 1;
result->SetNumberOfTransitions(new_nof);
}