commit | b5f146a02aeb28b89df6a2494ddf700a98d372ec | [log] [tgz] |
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author | caitp <caitp@igalia.com> | Wed Dec 07 15:19:52 2016 |
committer | Commit bot <commit-bot@chromium.org> | Wed Dec 07 15:20:33 2016 |
tree | 8a14dd2d40c2d20fd7dd58a92c2c37a253e5ad5d | |
parent | 378b6b22fb7925ac5b672335a54599f5739e7758 [diff] |
[ignition] desugar GetIterator() via bytecode rather than via AST Introduces: - a new AST node representing the GetIterator() algorithm in the specification, to be used by ForOfStatement, YieldExpression (in the case of delegating yield*), and the future `for-await-of` loop proposed in http://tc39.github.io/proposal-async-iteration/#sec-async-iterator-value-unwrap-functions. - a new opcode (JumpIfJSReceiver), which is useful for `if Type(object) is not Object` checks which are common throughout the specification. This node is easily eliminated by TurboFan. The AST node is desugared specially in bytecode, rather than manually when building the AST. The benefit of this is that desugaring in the BytecodeGenerator is much simpler and easier to understand than desugaring the AST. This also reduces parse time very slightly, and allows us to use LoadIC rather than KeyedLoadIC, which seems to have better baseline performance. This results in a ~20% improvement in test/js-perf-test/Iterators micro-benchmarks, which I believe owes to the use of the slightly faster LoadIC as opposed to the KeyedLoadIC in the baseline case. Both produce identical optimized code via TurboFan when the type check can be eliminated, and the load can be replaced with a constant value. BUG=v8:4280 R=bmeurer@chromium.org, rmcilroy@chromium.org, adamk@chromium.org, neis@chromium.org, jarin@chromium.org TBR=rossberg@chromium.org Review-Url: https://codereview.chromium.org/2557593004 Cr-Commit-Position: refs/heads/master@{#41555}
V8 is Google's open source JavaScript engine.
V8 implements ECMAScript as specified in ECMA-262.
V8 is written in C++ and is used in Google Chrome, the open source browser from Google.
V8 can run standalone, or can be embedded into any C++ application.
V8 Project page: https://github.com/v8/v8/wiki
Checkout depot tools, and run
fetch v8
This will checkout V8 into the directory v8
and fetch all of its dependencies. To stay up to date, run
git pull origin gclient sync
For fetching all branches, add the following into your remote configuration in .git/config
:
fetch = +refs/branch-heads/*:refs/remotes/branch-heads/* fetch = +refs/tags/*:refs/tags/*
Please follow the instructions mentioned on the V8 wiki.