[webkit-changes] [WebKit/WebKit] a6abdb: [JSC] Function#bind's default length should be 0

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: a6abdb2470fd861af34a0b62bcb0828665958f8e
      https://github.com/WebKit/WebKit/commit/a6abdb2470fd861af34a0b62bcb0828665958f8e
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-04-06 (Thu, 06 Apr 2023)

  Changed paths:
    A JSTests/stress/function-bind-proxy.js
    M Source/JavaScriptCore/dfg/DFGOperations.cpp
    M Source/JavaScriptCore/runtime/FunctionPrototype.cpp

  Log Message:
  -----------
  [JSC] Function#bind's default length should be 0
https://bugs.webkit.org/show_bug.cgi?id=254728
rdar://107408929

Reviewed by Alexey Shvayka.

We should use 0 for default length for Function#bind's JSBoundFunction.
And set PNaN only when we explicitly defer the computation of length
for JSBoundFunction (just wrapping JSFunction). PNaN is a signal that
it will lazily compute "length".

* JSTests/stress/function-bind-proxy.js: Added.
(f1):
* Source/JavaScriptCore/dfg/DFGOperations.cpp:
(JSC::DFG::JSC_DEFINE_JIT_OPERATION):
* Source/JavaScriptCore/runtime/FunctionPrototype.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):

Canonical link: https://commits.webkit.org/262692@main