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[regexp] Don't clone new JSRegExps when there is no feedback vector

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When creating a new JSRegExp for a literal, we sometimes create a
boilerplate and store it in the feedback vector. Then for future
creations, we can copy the boilerplate instead of re-creating the
regexp from scratch.

When we don't have a feedback vector, we currently create a
boilerplate, copy it and return the copy, and then throw out the
boilerplate, which is unnecessary. We can just return the first
JSRegExp we create.

Change-Id: I98b4e3a3082654ea989e0e6ba1524ce080b0125c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1776086
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63496}
This commit is contained in:
Peter Marshall 2019-08-29 18:35:51 +02:00 committed by Commit Bot
parent 14243f1206
commit 6498f8bb33
1 changed files with 5 additions and 4 deletions
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9
src/runtime/runtime-literals.cc
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@ -655,15 +655,16 @@ RUNTIME_FUNCTION(Runtime_CreateRegExpLiteral) {
DCHECK(maybe_vector->IsFeedbackVector());
vector = Handle<FeedbackVector>::cast(maybe_vector);
}
Handle<Object> boilerplate;
if (vector.is_null()) {
Handle<JSRegExp> new_regexp;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, boilerplate,
isolate, new_regexp,
JSRegExp::New(isolate, pattern, JSRegExp::Flags(flags)));
return *JSRegExp::Copy(Handle<JSRegExp>::cast(boilerplate));
return *new_regexp;
}
// Check if boilerplate exists. If not, create it first.
Handle<JSRegExp> boilerplate;
Handle<Object> literal_site(vector->Get(literal_slot)->cast<Object>(),
isolate);
if (!HasBoilerplate(literal_site)) {
@ -676,7 +677,7 @@ RUNTIME_FUNCTION(Runtime_CreateRegExpLiteral) {
}
vector->Set(literal_slot, *boilerplate);
}
return *JSRegExp::Copy(Handle<JSRegExp>::cast(boilerplate));
return *JSRegExp::Copy(boilerplate);
}
} // namespace internal