Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 76811693b10007dba19a08e3395e0c072c4bc0be
https://github.com/WebKit/WebKit/commit/76811693b10007dba19a08e3395e0c072c4bc0be
Author: Alexey Shvayka <ashva...@apple.com>
Date: 2024-02-28 (Wed, 28 Feb 2024)
Changed paths:
M JSTests/microbenchmarks/default-value-destructuring-array.js
R JSTests/microbenchmarks/destructuring-array-literal.js
M JSTests/microbenchmarks/destructuring-swap.js
M JSTests/test262/expectations.yaml
M Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
M Source/JavaScriptCore/parser/Nodes.h
Log Message:
-----------
[JSC] Remove ArrayPatternNode::emitDirectBinding()
https://bugs.webkit.org/show_bug.cgi?id=187085
<rdar://problem/121959952>
Reviewed by Yusuke Suzuki.
This patch removes special bytecode generation path for code like `[a, b] = [b,
a]` that wasn't
spec-compliant: it skipped invocation of iterator protocol, which was
observable when built-ins like
`Array.prototype[Symbol.iterator]` were modified.
There is no way to guard the special code path with some sort of built-ins
check without bloating
the bytecode size: we would still need to emit regular iterator protocol code,
which actually
isn't even slower after DFG / FTL, as demonstated by existing microbenchmark.
Only very obscure / synthetic tests are recorded to be slower after this change.
This patch was A/B tested not to affect JS3, SP2, and SP3.
Aligns JSC with the spec, V8, and SpiderMonkey.
ToT patch
destructuring-swap 53.4546+-0.1895 ^
51.3538+-0.2101 ^ definitely 1.0409x faster
default-value-destructuring-array 36.5455+-0.4078 !
105.0089+-0.4452 ! definitely 2.8734x slower
* JSTests/microbenchmarks/default-value-destructuring-array.js:
* JSTests/microbenchmarks/destructuring-array-literal.js:
Removed, it was very synthetic test targeting emitDirectBinding().
* JSTests/microbenchmarks/destructuring-swap.js:
* JSTests/test262/expectations.yaml: Mark 24 tests as passing.
* Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp:
(JSC::DestructuringAssignmentNode::emitBytecode):
(JSC::ArrayPatternNode::emitDirectBinding): Deleted.
* Source/JavaScriptCore/parser/Nodes.h:
(JSC::DestructuringPatternNode::isRestParameter const):
(JSC::DestructuringPatternNode::emitDirectBinding): Deleted.
Canonical link: https://commits.webkit.org/275474@main
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