Finally I zeroed in on 3 "calc" candidates from the stylesheet which are causing the CSS parser to fail:
height:calc(100vh - 200px) height:calc(100vh - 230px) max-height:calc(100vh - 200px) I think it is the very first one and the remaining two never get processed. I put in some debug statements in the code and the corresponding output for this is: ATUL: value->id = 0 propId = 1080 ATUL: in CSSPropertyHeight ATUL: in CSSPropertyWebkitLogicalHeight ATUL: in CSSCalcValue::create ATUL: in parseValueExpression, calling parseAdditiveValueExpression ATUL: calling CSSCalcBinaryOperation::create from parseAdditiveValueExpression ATUL: operatorCharacter = - ATUL: lhs = 1 rhs = 1 ATUL: leftSide category = ATUL: m_category = 5 5 ATUL: rightSide category = ATUL: m_category = 1 1 ATUL: m_category = 5 ASSERTION FAILED: leftSide->category() != CalcOther && rightSide->category() != CalcOther css/CSSCalculationValue.cpp(293) : static WTF::PassRefPtr<WebCore::CSSCalcBinaryOperation> WebCore::CSSCalcBinaryOperation::create(WTF::PassRefPtr<WebCore::CSSCalcExpressionNode>, WTF::PassRefPtr<WebCore::CSSCalcExpressionNode>, WebCore::CalcOperator) 1 0x12e8a80c bin/phantomjs() [0x12e8a80c] < stack trace removed > So the question is, is the calc expression valid one? Best regards, Atul. On Thu, Feb 9, 2017 at 2:17 PM, Atul Sowani <sow...@gmail.com> wrote: > @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 [1]) >> >> [1] 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-p >> age/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 >> >>>> webkit-dev@lists.webkit.org >> >>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >> > , >> > >> > _______________________________________________ >> > webkit-dev mailing list >> > webkit-dev@lists.webkit.org >> > https://lists.webkit.org/mailman/listinfo/webkit-dev >> >> >> -- >> Regards, >> Konstantin >> > >
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