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[parser] Improve hole check elision in async arrow funcs

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Use the position of commas in async arrow expressions to mark the
initializer position of any parameters that might have been set in the
preceding parameter.

This extends https://chromium-review.googlesource.com/c/v8/v8/+/1710671
to async arrow heads.

Bug: v8:8510, chromium:997320
Change-Id: I98e0ac817c7f53fbf1dced98fb6891a386ee7803
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1781057
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63542}
This commit is contained in:
Dan Elphick 2019-09-02 14:55:08 +01:00 committed by Commit Bot
parent bf78435b2c
commit afca89f848
2 changed files with 13 additions and 1 deletions
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6
src/parsing/parser-base.h
View File

@ -2566,6 +2566,7 @@ void ParserBase<Impl>::ParseArguments(
Consume(Token::LPAREN);
AccumulationScope accumulation_scope(expression_scope());
int variable_index = 0;
while (peek() != Token::RPAREN) {
int start_pos = peek_position();
bool is_spread = Check(Token::ELLIPSIS);
@ -2593,6 +2594,10 @@ void ParserBase<Impl>::ParseArguments(
argument = factory()->NewSpread(argument, start_pos, expr_pos);
}
args->Add(argument);
variable_index =
expression_scope()->SetInitializers(variable_index, peek_position());
if (!Check(Token::COMMA)) break;
}
@ -3123,7 +3128,6 @@ ParserBase<Impl>::ParseLeftHandSideContinuation(ExpressionT result) {
ParseArguments(&args, &has_spread, kMaybeArrowHead);
if (V8_LIKELY(peek() == Token::ARROW)) {
fni_.RemoveAsyncKeywordFromEnd();
expression_scope()->SetInitializers(0, peek_position());
next_arrow_function_info_.scope = maybe_arrow.ValidateAndCreateScope();
scope_snapshot.Reparent(next_arrow_function_info_.scope);
// async () => ...

8
test/mjsunit/regress/regress-crbug-997320.js Normal file
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@ -0,0 +1,8 @@
// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --no-lazy --stress-lazy-source-positions
// Flags: --enable-lazy-source-positions
async(a, b = a) => {};