ladybird/Libraries/LibJS/Position.h

/*
 * Copyright (c) 2023, Andreas Kling <andreas@ladybird.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Types.h>

namespace JS {

struct Position {
    size_t line { 0 };
    size_t column { 0 };
    size_t offset { 0 };
};

}
LibJS: Make line-and-column resolution fast for large minified JS Instead of caching start-of-line offsets, we now cache byte offsets at regular intervals. This fixes an issue where we had terrible performance on large minified JS, since that often means one very, VERY long line (with no line endings to cache). My machine was spending ~35ms per stack frame when throwing errors on some heavy minified websites, and after this patch, we now spend <1ms per stack frame. 2023-09-12 13:03:56 +02:00			`/*`
Meta: Update my e-mail address everywhere 2024-10-04 13:19:50 +02:00			`* Copyright (c) 2023, Andreas Kling <andreas@ladybird.org>`
LibJS: Make line-and-column resolution fast for large minified JS Instead of caching start-of-line offsets, we now cache byte offsets at regular intervals. This fixes an issue where we had terrible performance on large minified JS, since that often means one very, VERY long line (with no line endings to cache). My machine was spending ~35ms per stack frame when throwing errors on some heavy minified websites, and after this patch, we now spend <1ms per stack frame. 2023-09-12 13:03:56 +02:00			`*`
			`* SPDX-License-Identifier: BSD-2-Clause`
			`*/`

			`#pragma once`

LibJS: Cache source code positions more often The source code position cache was moved from a line based approach to a "chunk"-based approach to improve performance on large, minified JavaScript files with few lines, but this has had an adverse effect on _multi-line_ source files. Reintroduce some of the old behaviour by caching lines again, with some added sanity limits to avoid caching empty/overly small lines. Source code positions in files with few lines will still be cached less often, since minified JavaScript files can be assumed to be unusually large, and since stack traces for minified JavaScript are less useful as well. On WPT tests with large JavaScript dependencies like `css/css-masking/animations/clip-interpolation.html` this reduces the amount of time spent in `SourceCode::range_from_offsets` by as much as 99.98%, for the small small price of 80KB extra memory usage. 2024-12-01 22:21:18 +01:00			`#include <AK/Types.h>`

LibJS: Make line-and-column resolution fast for large minified JS Instead of caching start-of-line offsets, we now cache byte offsets at regular intervals. This fixes an issue where we had terrible performance on large minified JS, since that often means one very, VERY long line (with no line endings to cache). My machine was spending ~35ms per stack frame when throwing errors on some heavy minified websites, and after this patch, we now spend <1ms per stack frame. 2023-09-12 13:03:56 +02:00			`namespace JS {`

			`struct Position {`
			`size_t line { 0 };`
			`size_t column { 0 };`
			`size_t offset { 0 };`
			`};`

			`}`