Closed
Bug 1411030
Opened 7 years ago
Closed 7 years ago
Fails with -Werror=class-memaccess on dom/BindingUtils.h
Categories
(Core :: DOM: Core & HTML, defect)
Core
DOM: Core & HTML
Tracking
()
RESOLVED
FIXED
mozilla58
Tracking | Status | |
---|---|---|
firefox58 | --- | fixed |
People
(Reporter: Sylvestre, Assigned: andi)
References
(Blocks 1 open bug)
Details
Attachments
(1 file)
0:47.63 In file included from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/dom/ToJSValue.h:12:0, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/dom/WindowBinding.h:14, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/ScrollbarStyles.h:12, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsPresContext.h:41, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/dom/Element.h:28, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/PseudoElementHashEntry.h:10, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/EffectCompositor.h:13, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/ServoBindings.h:18, 0:47.63 from /root/firefox-gcc-last/intl/locale/nsLanguageAtomService.cpp:14, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/intl/locale/Unified_cpp_intl_locale0.cpp:47: 0:47.63 /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/dom/BindingUtils.h: In constructor 'mozilla::dom::ProtoAndIfaceCache::PageTableCache::PageTableCache()': 0:47.63 /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/dom/BindingUtils.h:482:40: error: 'void* memset(void*, int, size_t)' clearing an object of non-trivial type 'class mozilla::Array<mozilla::Array<JS::Heap<JSObject*>, 16>*, 97>'; use assignment or value-initialization instead [-Werror=class-memaccess] 0:47.63 memset(&mPages, 0, sizeof(mPages)); 0:47.63 ^ 0:47.63 In file included from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/Span.h:23:0, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsTSubstring.h:16, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsAString.h:22, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsSubstring.h:10, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsString.h:14, 0:47.63 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/nsStringGlue.h:21, 0:47.64 from /root/firefox-gcc-last/intl/locale/DateTimeFormat.h:12, 0:47.64 from /root/firefox-gcc-last/intl/locale/DateTimeFormat.cpp:7, 0:47.64 from /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/intl/locale/Unified_cpp_intl_locale0.cpp:2: 0:47.64 /root/firefox-gcc-last/obj-x86_64-pc-linux-gnu/dist/include/mozilla/Array.h:22:7: note: 'class mozilla::Array<mozilla::Array<JS::Heap<JSObject*>, 16>*, 97>' declared here 0:47.64 class Array 0:47.64 ^~~~~
Assignee | ||
Comment 1•7 years ago
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Here I don't think we should modify: Array() { memset(...) }, because if we do so we might end up in a similar scenario where we pass to Array first template argument as of a non TriviallyCopyable type that has undefined behavior for memset, memcpy etc. In this particular case I think the best approach would be to do a loop-initialization something similar with the destructor of the class.
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Comment 3•7 years ago
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mozreview-review |
Comment on attachment 8921390 [details] Bug 1411030 - memset only the underlying vector from the Array container. https://reviewboard.mozilla.org/r/192422/#review197634 ::: commit-message-ce1a8:1 (Diff revision 1) > +Bug 1411030 - do not use memset, on a non trivially type. r?froydnj "non trivially type" is not really a thing. Please correct the commit message. ::: dom/bindings/BindingUtils.h:482 (Diff revision 1) > - memset(&mPages, 0, sizeof(mPages)); > + for (size_t i = 0; i < ArrayLength(mPages); ++i) { > + mPages[i] = nullptr; > + } I am not super-excited about this change; it's more code, possibly slower, and the compiler (in some cases) will just turn it back into a memset anyway! Does the warning go away if you do: `memset(mPages.begin(), 0, sizeof(mPages));` instead?
Attachment #8921390 -
Flags: review?(nfroyd)
Assignee | ||
Comment 4•7 years ago
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(In reply to Nathan Froyd [:froydnj] from comment #3) > Comment on attachment 8921390 [details] > Bug 1411030 - do not use memset, on a non trivially type. > > https://reviewboard.mozilla.org/r/192422/#review197634 > > ::: commit-message-ce1a8:1 > (Diff revision 1) > > +Bug 1411030 - do not use memset, on a non trivially type. r?froydnj > > "non trivially type" is not really a thing. Please correct the commit > message. > > ::: dom/bindings/BindingUtils.h:482 > (Diff revision 1) > > - memset(&mPages, 0, sizeof(mPages)); > > + for (size_t i = 0; i < ArrayLength(mPages); ++i) { > > + mPages[i] = nullptr; > > + } > > I am not super-excited about this change; it's more code, possibly slower, > and the compiler (in some cases) will just turn it back into a memset anyway! > > Does the warning go away if you do: > > `memset(mPages.begin(), 0, sizeof(mPages));` > > instead? It should work, since the underlying type is a T*.
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Comment 6•7 years ago
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mozreview-review |
Comment on attachment 8921390 [details] Bug 1411030 - memset only the underlying vector from the Array container. https://reviewboard.mozilla.org/r/192422/#review197654 Thanks!
Attachment #8921390 -
Flags: review?(nfroyd) → review+
Pushed by nfroyd@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/a08737444fc3 memset only the underlying vector from the Array container. r=froydnj
Comment 8•7 years ago
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We're sorry - something has gone wrong while rewriting or rebasing your commits. The commits being pushed no longer match what was requested. Please file a bug.
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Comment 9•7 years ago
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bugherder |
https://hg.mozilla.org/mozilla-central/rev/a08737444fc3
Status: NEW → RESOLVED
Closed: 7 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla58
Reporter | ||
Updated•6 years ago
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Assignee: nobody → bpostelnicu
Updated•6 years ago
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Component: DOM → DOM: Core & HTML
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Description
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