Bug 157786 – Function with default parameter values that are arrow functions that capture this isn't working

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Saam Barati]

I.e
function foo(x = ()=>this) { return x() }

[Saam Barati]

This might actually be fixed on TOT. I'll check

[Saam Barati]

this is broken in ToT

[Radar WebKit Bug Importer]

<rdar://problem/26327329>

[GSkachkov]

Ups. 
Looks like very close to already fixed issue :-(
https://bugs.webkit.org/show_bug.cgi?id=157079
We did store of foo's 'this' in lexical scope after we generate default values in initializeDefaultParameterValuesAndSetupFunctionScopeStack. So we need to store 'this' earlier

[Saam Barati]

Created attachment 279318 [details]
patch

[WebKit Commit Bot]

Attachment 279318 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h:860:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:814:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:973:  Missing space before {  [whitespace/braces] [5]
Total errors found: 3 in 5 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Geoffrey Garen]

Comment on attachment 279318 [details]
patch

r=me

[Saam Barati]

Created attachment 279327 [details]
patch for landing

[WebKit Commit Bot]

Attachment 279327 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h:860:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:814:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:973:  Missing space before {  [whitespace/braces] [5]
Total errors found: 3 in 5 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Saam Barati]

Created attachment 279328 [details]
patch for landing

[WebKit Commit Bot]

Attachment 279328 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h:860:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:813:  Extra space before ( in function call  [whitespace/parens] [4]
ERROR: Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:972:  Missing space before {  [whitespace/braces] [5]
Total errors found: 3 in 5 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[WebKit Commit Bot]

Comment on attachment 279328 [details]
patch for landing

Clearing flags on attachment: 279328

Committed r201122: <http://trac.webkit.org/changeset/201122>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Benjamin Poulain]

There is a 7x regression in Sunspider's tofte. This patch is the only one in the range on Mozilla's bot.

Our bots also show the regression.

[Saam Barati]

(In reply to comment #14)
> There is a 7x regression in Sunspider's tofte. This patch is the only one in
> the range on Mozilla's bot.
> 
> Our bots also show the regression.

Ok. I'm fairly sure I know what would cause this.
I'll fix when I get into the office.

[Chris Dumez]

We see a ~5% JetStream regression on iOS in this range.

[Saam Barati]

fixing regression in:
https://bugs.webkit.org/show_bug.cgi?id=157908