1348477 - stylo: stop updating the stylist during PresShell destruction

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Cameron McCormack (:heycam)]

I noticed that when the PresShell for a document is being destroyed, we end up doing wasted work in re-building selector maps in response to the pref style sheet being removed.

    #0  DynamicAtom::AddRef (this=0x7f5ba9554670) at /z/moz/d/xpcom/ds/nsAtomTable.cpp:454
    #1  0x00007f5bd6963864 in Gecko_AddRefAtom (aAtom=0x7f5ba9554670) at /z/moz/d/layout/style/ServoBindings.cpp:743
    #2  0x00007f5bda2ef06c in style::gecko_string_cache::{{impl}}::from (ptr=0x7f5ba9554670) at /z/moz/d/servo/components/style/gecko_string_cache/mod.rs:293
    #3  0x00007f5bda3515a8 in style::gecko_string_cache::{{impl}}::clone (self=<optimized out>) at /z/moz/d/servo/components/style/gecko_string_cache/mod.rs:218
    #4  style::stylist::SelectorMap::get_id_name (rule=0x7ffc9f016b30) at /z/moz/d/servo/components/style/stylist.rs:1086
    #5  0x00007f5bda351131 in style::stylist::SelectorMap::insert (self=0x7f5bbc2a5440, rule=...) at /z/moz/d/servo/components/style/stylist.rs:1061
    #6  0x00007f5bda34c536 in style::stylist::{{impl}}::add_stylesheet::{{closure}} (rule=0x7f5ba267c380) at /z/moz/d/servo/components/style/stylist.rs:250
    #7  0x00007f5bda356429 in style::stylesheets::effective_rules<closure> (rules=..., device=0x7f5bbc3a5c50, f=0x7ffc9f017310) at /z/moz/d/servo/components/style/stylesheets.rs:748
    #8  0x00007f5bda3560f7 in style::stylesheets::Stylesheet::effective_rules<closure> (self=0x7f5ba97c4130, device=0x7f5bbc3a5c50, f=...) at /z/moz/d/servo/components/style/stylesheets.rs:725
    #9  0x00007f5bda34c197 in style::stylist::Stylist::add_stylesheet (self=0x7f5bbc2a5410, stylesheet=0x7f5ba97c4130) at /z/moz/d/servo/components/style/stylist.rs:236
    #10 0x00007f5bda34b633 in style::stylist::Stylist::update (self=0x7f5bbc2a5410, doc_stylesheets=..., ua_stylesheets=..., stylesheets_changed=true) at /z/moz/d/servo/components/style/stylist.rs:204
    #11 0x00007f5bda30b46f in style::gecko::data::PerDocumentStyleDataImpl::flush_stylesheets (self=0x7f5bab2b8ec8) at /z/moz/d/servo/components/style/gecko/data.rs:99
    #12 0x00007f5bd9ed4398 in geckoservo::glue::Servo_StyleSet_RemoveStyleSheet (raw_data=0x7f5bab2b8ec0, raw_sheet=0x7f5bc1996630, flush=true) at /z/moz/d/servo/ports/geckolib/glue.rs:478
    #13 0x00007f5bd698726b in mozilla::ServoStyleSet::RemoveStyleSheet (this=0x7f5ba708b500, aType=mozilla::SheetType::User, aSheet=0x7f5bc1d852c0) at /z/moz/d/layout/style/ServoStyleSet.cpp:461
    #14 0x00007f5bd44ad487 in mozilla::StyleSetHandle::Ptr::RemoveStyleSheet (this=0x7f5bbbf58018, aType=mozilla::SheetType::User, aSheet=0x7f5bc1d852c0) at /z/moz/d/obj/dist/include/mozilla/StyleSetHandleInlines.h:160
    #15 0x00007f5bd6b519d7 in mozilla::PresShell::RemovePreferenceStyles (this=0x7f5bbbf58000) at /z/moz/d/layout/base/PresShell.cpp:1510
    #16 0x00007f5bd6b4fc70 in mozilla::PresShell::Destroy (this=0x7f5bbbf58000) at /z/moz/d/layout/base/PresShell.cpp:1294
    #17 0x00007f5bd6bd634d in nsDocumentViewer::DestroyPresShell (this=0x7f5bb1b0ebd0) at /z/moz/d/layout/base/nsDocumentViewer.cpp:4574
    #18 0x00007f5bd6bd280f in nsDocumentViewer::Hide (this=0x7f5bb1b0ebd0) at /z/moz/d/layout/base/nsDocumentViewer.cpp:2180
    #19 0x00007f5bd83875c3 in nsDocShell::SetVisibility (this=0x7f5ba974f000, aVisibility=false) at /z/moz/d/docshell/base/nsDocShell.cpp:6513
    #20 0x00007f5bd44945ad in nsFrameLoader::Hide (this=0x7f5ba98d43d0) at /z/moz/d/dom/base/nsFrameLoader.cpp:1295
    #21 0x00007f5bd6de3eef in nsHideViewer::Run (this=0x7f5ba268e8d0) at /z/moz/d/layout/generic/nsSubDocumentFrame.cpp:928
    #22 0x00007f5bd41efb2c in nsContentUtils::RemoveScriptBlocker () at /z/moz/d/dom/base/nsContentUtils.cpp:5264
    #23 0x00007f5bd3b7c719 in nsAutoScriptBlocker::~nsAutoScriptBlocker (this=0x7ffc9f0181a8) at /z/moz/d/dom/base/nsContentUtils.h:2938
    #24 0x00007f5bd6bd636e in nsDocumentViewer::DestroyPresShell (this=0x7f5bad063a10) at /z/moz/d/layout/base/nsDocumentViewer.cpp:4576
    #25 0x00007f5bd6bd280f in nsDocumentViewer::Hide (this=0x7f5bad063a10) at /z/moz/d/layout/base/nsDocumentViewer.cpp:2180
    #26 0x00007f5bd83875c3 in nsDocShell::SetVisibility (this=0x7f5bbc5b2800, aVisibility=false) at /z/moz/d/docshell/base/nsDocShell.cpp:6513
    #27 0x00007f5bd44945ad in nsFrameLoader::Hide (this=0x7f5bbbfa2f50) at /z/moz/d/dom/base/nsFrameLoader.cpp:1295
    #28 0x00007f5bd6de3eef in nsHideViewer::Run (this=0x7f5ba19700b0) at /z/moz/d/layout/generic/nsSubDocumentFrame.cpp:928
    #29 0x00007f5bd41efb2c in nsContentUtils::RemoveScriptBlocker () at /z/moz/d/dom/base/nsContentUtils.cpp:5264
    #30 0x00007f5bd3b7c719 in nsAutoScriptBlocker::~nsAutoScriptBlocker (this=0x7ffc9f0184a8) at /z/moz/d/dom/base/nsContentUtils.h:2938
    #31 0x00007f5bd6bd636e in nsDocumentViewer::DestroyPresShell (this=0x7f5bc4b76b40) at /z/moz/d/layout/base/nsDocumentViewer.cpp:4576
    #32 0x00007f5bd6bcf2a8 in nsDocumentViewer::Destroy (this=0x7f5bc4b76b40) at /z/moz/d/layout/base/nsDocumentViewer.cpp:1708
    #33 0x00007f5bd836502f in nsDocShell::Destroy (this=0x7f5bb24e3800) at /z/moz/d/docshell/base/nsDocShell.cpp:5868
    #34 0x00007f5bd83f49be in nsXULWindow::Destroy (this=0x7f5bb243f9d0) at /z/moz/d/xpfe/appshell/nsXULWindow.cpp:501
    ...

Comment 1

[u459114]

Find a way to supress stylist updat while PresShell is destroying.

Comment 2

[Bobby Holley (:bholley)]

Just checking - bz, is this still unfixed after bug 1361843?

Comment 3

[Boris Zbarsky [:bzbarsky]]

I think it's pretty much fixed.  We're still clearing the stylist, before we then go to destroy it, so there might be a tiny amount of wasted work there, maybe.  But we're not going to do the rebuild unless someone asks for styles after the pref stylesheet is removed, which they better not!