@Konstantin thanks for the suggestions. I disabled CSS JIT on x85 but there was no negative impact on the results on x86. So I guess the issue is a genuine ppc64le problem. I have picked up the starting points mentioned in this thread earlier and debugging the issue. I have also isolated the issue to a single CSS file which is causing the problem. Now I am trying to isolate the exact entry in the CSS file which is causing the trouble.
Thanks! Atul. On Tue, Feb 7, 2017 at 3:53 PM, Konstantin Tokarev <annu...@yandex.ru> wrote: > > > 07.02.2017, 12:55, "Atul Sowani" <sow...@gmail.com>: > > Thanks Geoffrey, Alex, Yoav for the debugging pointer. I am debugging > the issue further using this information and will most likely need some > more help in immediate future as well. > > > > Unfortunately, I don't have a stand-alone test case which can be tested > with qtwebkit. I am trying to load a page using PhantomJS and it's > crashing. The typical URLs which cause it to crash are http://engadget.com > and http://cnn.com - both of these load without any issue on x86 platform > though, so the issue seems to be specific to ppc64le. > > A few suggestions: > > 1. I suppose you are building with disabled JIT, as WebKit does not > implement JIT for any PPC variant in official tree. This may introduce > subtle differences in behavior, for example I once encountered layout test > that was failing only when CSS JIT was disabled. You can try building > without JIT on x86_64 and compare. > > 2. It might be miscompilation, as your platform may not be as thoroughly > tested as more mainstream ones. You can try to build with -O0, -O1, -O2 > (default is -O3). Alternatively, try building with different compiler (at > least GCC and Clang support ppc64le and are fine for WebKit, xlC may not > work though), or try different version of your compiler. > > 3. Note that webkit-qt list is more appropriate for issues specific for > QtWebKit. Make sure you are using latest release (technology preview 5 at > the moment ) > >  https://github.com/annulen/webkit/releases/tag/qtwebkit-tp5 > > > > > Thanks, > > Atul. > > > > On Mon, Feb 6, 2017 at 5:56 PM, Yoav Weiss <y...@yoav.ws> wrote: > >> Hi Atul, > >> > >> I second Alex's suggestion (perhaps followed by > HTMLLinkElement::process() and other places in that file that refer to > `hrefAttr`). > >> If you have a test case online, I could try to take a look and maybe > provide more guidance. > >> > >> Cheers :) > >> Yoav > >> > >> On Fri, Feb 3, 2017 at 9:19 PM Alex Christensen <achristen...@apple.com> > wrote: > >>> I would start looking at HTMLLinkElement::parseAttribute. > >>> LinkHeader.cpp contains parsers for link headers, which are related. > Yoav knows more about those. Those parsers ought to be united more. > >>> > >>>> On Feb 3, 2017, at 1:17 AM, Atul Sowani <sow...@gmail.com> wrote: > >>>> At present I am focusing on CSSParser::findURI() particularly > and CSSParser::realLex() other related functionality in CSSParser.cpp > - hope I am on right track. ;-) > >>>> > >>>> Please let me know if I should be looking at some other functionality > as well to resolve this issue. > >>>> > >>>> Thanks! > >>>> Atul. > >>>> > >>>> On Fri, Feb 3, 2017 at 2:33 PM, Atul Sowani <sow...@gmail.com> wrote: > >>>>> Hi, > >>>>> > >>>>> I came across an issue in qtwebkit CSS parser while working on a > PhantomJS crash. The issue seems to be with parsing of <link rel="..." > href="..."> type elements in an HTML page. What I observed is that the > parser is trying to interpret the value for href given inside > double-quotes. The value contains a "-" (e.g. " > http://some.domain.com/some-page-etc-etc"). The "-" sign is being > interpreted as minus and then things go wrong. In another case I found that > "\g" embedded in the value (e.g. "http://some.domain.com/some- > page/global/something") is also creating issues. In essence, the parser > is trying to interpret the value, which I believe, it should not. > >>>>> > >>>>> I am willing to dive further into it to debug and fix the issue, but > looking at the complexity and size of WebCore, I think I would benefit a > lot to expedite a fix, if I could get some tips about which code > area/functionality I should specifically focus in the WebCore. Looking > forward to some help in this regard. > >>>>> > >>>>> Thanks, > >>>>> Atul. > >>>> _______________________________________________ > >>>> webkit-dev mailing list > >>>> firstname.lastname@example.org > >>>> https://lists.webkit.org/mailman/listinfo/webkit-dev > > , > > > > _______________________________________________ > > webkit-dev mailing list > > email@example.com > > https://lists.webkit.org/mailman/listinfo/webkit-dev > > > -- > Regards, > Konstantin >
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