[swift-dev] Inability to leverage privacy in the stdlib

Dave Abrahams dabrahams at apple.com
Tue Nov 1 13:19:07 CDT 2016


on Tue Nov 01 2016, Alexis <swift-dev-AT-swift.org> wrote:

> Hmm, I excitedly prototyped out refactoring HashedCollections to
> properly use privacy and decent naming since I’m clobbering the whole
> file with the new indexing stuff anyway. Unfortunately I hit a linker
> error. I can’t seem to produce a reduced test case.

If you are doing privacy inside the stdlib, then this is similar to the
experience I recall having the last time I tried to do it.  I'm pretty
sure that's what the frontend team means when they say that it's
unsupported.

> Making similar but smaller changes to other files seems to always
> work.
>
> The commit of interest is this:
>
> https://github.com/apple/swift/commit/851228a1d59e292b020c16a0fba4561a76f8fec5
> <https://github.com/apple/swift/commit/851228a1d59e292b020c16a0fba4561a76f8fec5>
>
> But it requires all the native indexing stuff I’ve done: 
>
> https://github.com/apple/swift/compare/master...Gankro:dsindex2?expand=1
> <https://github.com/apple/swift/compare/master...Gankro:dsindex2?expand=1>
>
> The error I get:
>
> FAILED: : &&
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++
> -fno-stack-protector -stdlib=libc++ -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wcovered-switch-default -Wnon-virtual-dtor
> -Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -fcolor-diagnostics -Wdocumentation
> -Wimplicit-fallthrough -Wunreachable-code -Woverloaded-virtual -O2 -isysroot
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk
> -dynamiclib -Wl,-headerpad_max_install_names -stdlib=libc++ -target x86_64-apple-macosx10.9
> -isysroot
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk
> -arch x86_64 -F
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk/../../../Developer/Library/Frameworks
> -mmacosx-version-min=10.9 -lobjc
> -Wl,-sectcreate,__TEXT,__info_plist,/Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/swift-macosx-x86_64/stdlib/internal/SwiftExperimental/Info.plist
> -Wl,-application_extension
> -L/Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/swift-macosx-x86_64/./lib/swift/macosx/x86_64
> -L/Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/swift-macosx-x86_64/./bin/../lib/swift/macosx/x86_64
> -L/Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/swift-macosx-x86_64/./bin/../lib/swift/macosx
> -o lib/swift/macosx/x86_64/libswiftSwiftExperimental.dylib -install_name
> @rpath/libswiftSwiftExperimental.dylib
> stdlib/internal/SwiftExperimental/macosx/x86_64/SwiftExperimental.o
> -L/Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/llvm-macosx-x86_64/./lib
> lib/swift/macosx/x86_64/libswiftCore.dylib -framework Foundation -framework CoreFoundation && :
> Undefined symbols for architecture x86_64:
>   "type metadata accessor for Swift.(VariantSetStorage in _69BD46AE5A11D8B70E9CADC1ECE9CF76)",
> referenced from:
>       Swift.Set.formUnion <A where A1: Swift.Sequence, A == A1.Iterator.Element> (A1) -> () in
> SwiftExperimental.o
>       Swift.Set.init <A where A1: Swift.Sequence, A == A1.Iterator.Element> (A1) -> Swift.Set<A> in
> SwiftExperimental.o
>       Swift.Set.intersection (Swift.Set<A>) -> Swift.Set<A> in SwiftExperimental.o
>       Swift.Set.formSymmetricDifference (Swift.Set<A>) -> () in SwiftExperimental.o
> ld: symbol(s) not found for architecture x86_64
> clang: error: linker command failed with exit code 1 (use -v to see invocation)
> [648/1027] Compiling
> /Users/Beingessner/dev/swift/build/Ninja-RelWithDebInfoAssert/swift-macosx-x86_64/stdlib/public/SwiftOnoneSupport/macosx/x86_64/SwiftOnoneSupport.o
> ninja: build stopped: subcommand failed.
> utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting
>
>> On Nov 1, 2016, at 12:10 PM, Alexis via swift-dev <swift-dev at swift.org> wrote:
>> 
>> I made a PR with some basic privacy usage for Array, and everything seems to be working on OSX,
> but not Linux.
>> 
>> https://github.com/apple/swift/pull/5573 <https://github.com/apple/swift/pull/5573>
>> 
>> Exit Code: 1
>> 
>> Command Output (stderr):
>> --
>> /usr/bin/ld.gold: error:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftSwiftOnoneSupport.a(SwiftOnoneSupport.o):
>> multiple definition of
>> '_TTSfq4n_d___TTSgq5Si___TZFVs15ContiguousArrayP33_4E8E8F8E53AAC7AA89B428DCA7DB222B11_copyBufferfRGVs22_ContiguousArrayBufferx_T_'
>> /usr/bin/ld.gold:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftCore.a(Swift.o):
>> previous definition here
>> /usr/bin/ld.gold: error:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftSwiftOnoneSupport.a(SwiftOnoneSupport.o):
>> multiple definition of
>> '_TTSfq4n_d___TTSgq5Vs4Int8___TZFSaP33_4E8E8F8E53AAC7AA89B428DCA7DB222B11_copyBufferfRGVs22_ContiguousArrayBufferx_T_'
>> /usr/bin/ld.gold:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftCore.a(Swift.o):
>> previous definition here
>> /usr/bin/ld.gold: error:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftSwiftOnoneSupport.a(SwiftOnoneSupport.o):
>> multiple definition of
>> '_TTSfq4n_d___TTSgq5Vs5UInt8___TZFSaP33_4E8E8F8E53AAC7AA89B428DCA7DB222B11_copyBufferfRGVs22_ContiguousArrayBufferx_T_'
>> /usr/bin/ld.gold:
>> /home/buildnode/jenkins/workspace/swift-PR-Linux/branch-master/buildbot_linux/swift-linux-x86_64/lib/swift_static/linux/libswiftCore.a(Swift.o):
>> previous definition here
>> clang-4.0: error: linker command failed with exit code 1 (use -v to see invocation)
>> <unknown>:0: error: link command failed with exit code 1 (use -v to see invocation)
>> 
>> --
>> 
>> Close... (made copyBuffer private)
>> 
>> 
>>> On Oct 29, 2016, at 6:04 PM, Dave Abrahams via swift-dev <swift-dev at swift.org <mailto:swift-dev at swift.org>> wrote:
>>> 
>>> 
>>> on Sat Oct 29 2016, Alexis <swift-dev-AT-swift.org <http://swift-dev-at-swift.org/>> wrote:
>>> 
>>>>> On Oct 29, 2016, at 12:13 AM, Slava Pestov <spestov at apple.com <mailto:spestov at apple.com>> wrote:
>>>>> 
>>>>> It will become the default, but not yet, so yeah, you shouldn’t merge anything that only builds
>>>> with this flag set.
>>>>> 
>>>>> Can you share the patch that adds private modifiers along with the
>>>>> linker errors you are seeing? Now would be a good time to sort out
>>>>> these issues.
>>>> 
>>>> I’m actually having trouble reproducing this now? I just rebased my
>>>> branches onto master and using private/fileprivate on types, aliases,
>>>> and functions seems to work perfectly fine (I tried a few things in
>>>> Array and Dictionary). Did something interesting just get merged?
>>> 
>>> I suggest you try making and testing a pull request.  Often things seem
>>> to work because of the way we build and test locally, but fail in the
>>> full CI environment.
>>> 
>>>> 
>>>>> 
>>>>>> On Oct 28, 2016, at 4:16 PM, Alexis Beingessner <abeingessner at apple.com <mailto:abeingessner at apple.com>
>>>> <mailto:abeingessner at apple.com <mailto:abeingessner at apple.com>>> wrote:
>>>>>> 
>>>>>> Won't merging anything relying on this flag break the build? Is this going to become the "new"
>>>> default soon?
>>>>>> 
>>>>>> On Oct 28, 2016, at 6:43 PM, Slava Pestov <spestov at apple.com <mailto:spestov at apple.com> <mailto:spestov at apple.com <mailto:spestov at apple.com>>> wrote:
>>>>>> 
>>>>>>> 
>>>>>>>> On Oct 23, 2016, at 4:13 PM, Michael Gottesman via swift-dev
>>>>>>>> <swift-dev at swift.org <mailto:swift-dev at swift.org> <mailto:swift-dev at swift.org <mailto:swift-dev at swift.org>>> wrote:
>>>>>>>> 
>>>>>>>> 
>>>>>>>>> On Oct 23, 2016, at 3:30 PM, Alexis Beingessner via swift-dev
>>>>>>>>> <swift-dev at swift.org <mailto:swift-dev at swift.org> <mailto:swift-dev at swift.org <mailto:swift-dev at swift.org>>> wrote:
>>>>>>>>> 
>>>>>>>>> Dave pointed out to me this week that the build crashes if the
>>>>>>>>> stdlib tries to use private/fileprivate. I tried it myself and
>>>>>>>>> lo and behold the linker can't find the private symbols. He
>>>>>>>>> couldn't recall what about the build caused that, though.
>>>>>>>>> 
>>>>>>>>> Can anyone recall why this is? How hard is it to fix?
>>>>>>>> 
>>>>>>>> I am not 100% sure, but if it happens only with the stdlib and
>>>>>>>> has to do with access control, I wouldn't be surprised if it has
>>>>>>>> to do with -sil-serialize-all and friends. But I may be
>>>>>>>> correct. I think Jordan is the right person to answer this
>>>>>>>> question.
>>>>>>>> 
>>>>>>>> What do you think Jordan?
>>>>>>>> Michael
>>>>>>> 
>>>>>>> Hi Alexis,
>>>>>>> 
>>>>>>> You can build the stdlib without sil-serialize-all now by passing a flag to build-script:
>>>>>>> 
>>>>>>> ./utils/build-script — --swift-stdlib-enable-resilience
>>>>>>> 
>>>>>>> Give that a shot and see if it fixes the issues you’re having with ‘private’.
>>>>>>> 
>>>>>>>> 
>>>>>>>>> _______________________________________________
>>>>>>>>> swift-dev mailing list
>>>>>>>>> swift-dev at swift.org <mailto:swift-dev at swift.org> <mailto:swift-dev at swift.org <mailto:swift-dev at swift.org>>
>>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-dev <https://lists.swift.org/mailman/listinfo/swift-dev>
>>>> <https://lists.swift.org/mailman/listinfo/swift-dev <https://lists.swift.org/mailman/listinfo/swift-dev>>
>>>>>>>> 
>>>>>>>> _______________________________________________
>>>>>>>> swift-dev mailing list
>>>>>>>> swift-dev at swift.org <mailto:swift-dev at swift.org> <mailto:swift-dev at swift.org <mailto:swift-dev at swift.org>>
>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-dev <https://lists.swift.org/mailman/listinfo/swift-dev>
>>>> <https://lists.swift.org/mailman/listinfo/swift-dev <https://lists.swift.org/mailman/listinfo/swift-dev>>
>>>>>>> 
>>>>> 
>>>> 
>>>> _______________________________________________
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>>>> 
>>> 
>>> -- 
>>> -Dave
>>> 
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-- 
-Dave



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