662969 - Silence the clang warnings issued because of alignment requirements increase when compiling jsparse.h

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[(no longer active)]

These warnings drive me nuts.  We get thousands of them when compiling jsparse.h.

In file included from /Users/ehsanakhgari/moz/tmp/js/src/jsatom.cpp:58:
/Users/ehsanakhgari/moz/tmp/js/src/jsparse.h:654:16: warning: cast from 'char *' to 'JSParseNode *' increases required alignment from 1 to 8 [-Wcast-align]
        return (JSParseNode *)((char *)pn_tail - offsetof(JSParseNode, pn_next));
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Comment 1

[(no longer active)]

Attachment: Patch (v1)

Comment 2

[Jeff Walden [:Waldo]]

Comment on attachment 538143 [details] [diff] [review]
Patch (v1)

>-        return (JSParseNode *)((char *)pn_tail - offsetof(JSParseNode, pn_next));
>+        return (JSParseNode *)(void *)((char *)pn_tail - offsetof(JSParseNode, pn_next));

More uintptr_t:

>+        return (JSParseNode *)(uintptr_t(pn_tail) - offsetof(JSParseNode, pn_next));

(reinterpret_cast<> butts up against the JS line length limit in this case, hence why I wouldn't use it.)

Comment 3

[(no longer active)]

http://hg.mozilla.org/tracemonkey/rev/f25adc3d6d65

Comment 4

[Chris Leary [:cdleary] (not checking bugmail)]

cdleary-bot mozilla-central merge info:
http://hg.mozilla.org/mozilla-central/rev/f25adc3d6d65