Tighten minimumRegisterRequirements()
https://bugs.webkit.org/show_bug.cgi?id=129538
Reviewed by Andreas Kling.
Source/WebCore:
Fix small things that made minimumRegisterRequirements() a little optimistic
when dealing with attributes.
Test: fast/selectors/adjacent-descendant-tail-register-requirement.html
* cssjit/SelectorCompiler.cpp:
(WebCore::SelectorCompiler::SelectorCodeGenerator::SelectorCodeGenerator):
Attribute Set does not do value matching, the case sensitive value matching is irrelevant
The problem is that flag is also used by minimumRegisterRequirements()
to find if one more register is needed.
Set the flag to case sensitive to avoid reserving one extra register.
(WebCore::SelectorCompiler::minimumRegisterRequirements):
Use a new backtrackingFlag to know if there is a descendant tail, thus a backtracking register
reserved.
This is better than using the backtracking action because the backtracking chain could be
an adjacent chain inside a descendant chain.
The flags are designed for that, just set one for minimumRegisterRequirements().
The 2 extra registers for the attribute count and address become limited to all attributes
except the last one. We don't keep a copy for the last matching, those registers were not needed.
(WebCore::SelectorCompiler::SelectorCodeGenerator::computeBacktrackingInformation):
LayoutTests:
* fast/selectors/adjacent-descendant-tail-register-requirement-expected.txt: Added.
* fast/selectors/adjacent-descendant-tail-register-requirement.html: Added.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@164932 268f45cc-cd09-0410-ab3c-d52691b4dbfc
5 files changed
