513701 - JS_ISSPACE has wrong space character check

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Robert Sayre]

+++ This bug was initially created as a clone of Bug #513379 +++

js_SkipWhiteSpace should check for characters matching the StrWhiteSpaceChar production in the ES5 spec. These are both whitespace and line terminators:

whitespace:
\u0009 Tab <TAB> 
\u000B Vertical Tab <VT> 
\u000C Form Feed <FF> 
\u0020 Space <SP> 
\u00A0 No-break space <NBSP> 
\uFEFF Byte Order Mark <BOM> 
Any other Unicode ―space separator <USP> 

line terminators:
\u000A Line Feed <LF> 
\u000D Carriage Return  <CR> 
\u2028 Line separator <LS> 
\u2029 Paragraph separator <PS>

Comment 1

[Andreas Gal :gal]

Attachment: patch

Comment 2

[Brendan Eich [:brendan]]

Comment on attachment 397992 [details] [diff] [review]
patch

>diff --git a/js/src/jsstr.h b/js/src/jsstr.h
>--- a/js/src/jsstr.h
>+++ b/js/src/jsstr.h
>@@ -520,17 +520,17 @@ extern const bool js_alnum[];
> #define JS_ISDIGIT(c)   (JS_CTYPE(c) == JSCT_DECIMAL_DIGIT_NUMBER)
> 
> static inline bool
> JS_ISSPACE(jschar c)
> {
>     unsigned w = c;
> 
>     if (w < 256)
>-        return w <= ' ' && (w == ' ' || (9 <= w && w <= 0xD));
>+        return (w <= ' ' && (w == ' ' || (9 <= w && w <= 0xD))) || (w == 0xA0);

Inconsistency! You didn't over-parenthesize w == ' ' (did WebKit? :-P so don't over-paren w == 0xA0:

        return (w <= ' ' && (w == ' ' || (9 <= w && w <= 0xD))) || w == 0xA0;

If there is a better machine code sequence, I hope GCC turns on the super-optimizer, runs it on this, and does even better some day.

/be

Comment 3

[Andreas Gal :gal]

http://hg.mozilla.org/tracemonkey/rev/e419ca583031

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

http://hg.mozilla.org/mozilla-central/rev/e419ca583031

Comment 5

[Robert Sayre]

http://hg.mozilla.org/releases/mozilla-1.9.2/rev/06fa314f56f2