[libcxx-dev] libcxxbi, itanium symbols for Mac OS 10.13

Tue Jun 2 11:19:49 PDT 2020

Just to be clear -- I didn't have to do any of that.

Just

1. install clang-9.0
2. use it to build TOT with the build line you outlined

> export CXX=/path/to/clang++-9.0
> export CC=/path/to/clang-9.0
> cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$BUILD_DIR/install -DLLVM_ENABLE_PROJECTS="libcxx;libcxxabi" $SRC_DIR
> ninja -j8

done.

Ken

On 2020-06-02, at 11:00 AM, llvm at dyatkovskiy.com wrote:

> + ldionne@
>  
> Ken, Louis,
>  
> After all also can confirm similar conditions.
>  
> 1. It won't built latest Xcode clang I was able to get for 10.13, namely this one:
> Apple LLVM version 10.0.0 (clang-1000.10.43.1)
> Target: x86_64-apple-darwin17.7.0
> Thread model: posix
> InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
>  
> 2. I was only able to get it pass through with the following bootstrap sequence:
>   2.1. Get TOT llvm
>   Phase 1
>   2.2. Build it with clang enabled and with *static* libcxx and libcxxabi projects enabled. So, following options should be "OFF" in cmake:
>      * LIBCXXABI_ENABLE_SHARED
>      * LIBCXX_ENABLE_SHARED
>      Note, "check-cxx" rule will give you a lot of errors on this step. Just because there are no shared libs.
>   2.3. install it into custom dir
>   Phase 2
>   2.4. Build libcxx and libcxx with CMAKE_C_COMPILER and CMAKE_CXX_COMPILER set to toolchain you get on step 2.3.
>   2.5. Install into desired dir. The result would be working libcxx and libcxxabi (both static and shared).
>  
> Conclusions.
> Solutions mentioned in this thread are quite different from standard guidelines. May be we should update them?
>  
> -Stepan
>  
> 02.06.2020, 20:20, "Ken Cunningham" <ken.cunningham.webuse at gmail.com>:
> We find it builds fine with an Xcode clang > 1001. It does not build with the latest Xcode clang  available on 10.13, but it does build with clang-9.0 on 10.13 (just confirmed it with your build line).
>  
> Here's a log from 10.13 successfully building libc++abi.dyib (and the rest of clang) using clang-9 last night.
>  
> <https://build.macports.org/builders/ports-10.13_x86_64-builder/builds/85088/steps/install-port/logs/stdio>.
>  
>  
> hope this helps,
>  
> K
>  
>  
>  
> On Jun 2, 2020, at 6:42 AM, Louis Dionne via libcxx-dev <libcxx-dev at lists.llvm.org> wrote:
>  
> Hmm, something like a year old clang should work, so this must be an actual bug. Can you provide a link to a gist containing the full output of the build command? Also, please use `-v` so we can see individual compiler invocations.
>  
> Thanks,
> Louis
>  
> On Jun 2, 2020, at 04:50, llvm at dyatkovskiy.com wrote:
>  
> Nope, it fails for TOT as well.
>  
> commit e70cf280f80c0933dd500ff18c7a17af8057b28c (HEAD -> master, origin/master, origin/HEAD)
> Author: Sam Parker <sam.parker at arm.com>
> Date: Tue Jun 2 09:04:20 2020 +0100
>  
> [NFC][ARM][AArch64] Test runs
>  
> Add code size tests runs for memory ops for both architectures.
>  
> Error message:
>  
> Undefined symbols for architecture x86_64:
> "__ZTIDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTIPDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTIPKDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTSDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTSPDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTSPKDu", referenced from:
> -exported_symbol[s_list] command line option
> ld: symbol(s) not found for architecture x86_64
>  
> Thanks!
> Stepan
>  
> 02.06.2020, 02:50, "via libcxx-dev" <libcxx-dev at lists.llvm.org>:
> I'm sorry, I reproduced this issue only with clang version which is 4 weeks old. Commit ff4a3ee4.
> It wasn't yet tested with newer clang versions. I'll check tomorrow and let you know.
>  
> Thanks!
> Stepan
>  
> 02.06.2020, 01:12, "via libcxx-dev" <libcxx-dev at lists.llvm.org>:
> Louis,
> how recent clang should be? I have this error for 31th of May version, for this commit 595212569.
>  
> Thanks!
>  
> 01.06.2020, 23:54, "Louis Dionne" <ldionne at apple.com>:
> Hi,
>  
> I just updated http://llvm.org/PR43749, which I wasn't aware of. As I explain in the bug report:
>  
>     The issue is that the compiler emits type information for fundamental types in libc++abi, and your compiler doesn't know about char8_t yet, so it doesn't emit the type information for those. libc++abi tries to export these symbols and it fails to do so, because they haven't been generated in the dylib by the compiler.
>  
>     Getting a linker error is quite nice, because otherwise you'd be producing a libc++abi.dylib that doesn't work properly at runtime (say if you try to use typeid(char8_t) in your program).
>  
> I hope that answers your question. The problem should go away if you use a recent Clang. If it doesn't please ping me again.
>  
> Thanks,
> Louis
>  
> On Jun 1, 2020, at 15:39, llvm at dyatkovskiy.com wrote:
>  
> Hi Louis!
>  
> I found your commit in llvm-project, libcxxabi, namely this one:
>  
> commit 223df5b54021cfa4c67d4e09e1dc1b3b9e6a9de7 (refs/bisect/bad)
> Author: Louis Dionne <ldionne at apple.com>
> Date: Thu Jun 27 20:17:22 2019 +0000
>  
> In this commit you added exported symbols for different platforms for libcxxabi, for apple:
>  
> I'm currently trying to build it for Mac OS 10.13.6, x86_64, and bumped into unresolved symbols errors:
>  
> Undefined symbols for architecture x86_64:
> "__ZTIDu", referenced from:
> -exported_symbol[s_list] command line option
> "__ZTIPDu", referenced from:
> -exported_symbol[s_list] command line option
>  
> I noticed that you added itanium-base.exp for APPLE platforms by default (no other conditions):
>  
> > if (APPLE)
> > target_link_libraries(cxxabi_shared PRIVATE "-Wl,-exported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/itanium-base.exp")
>  
> I'm not expert of x86_64 arch, especially for darwin. Are we using Itanium ABI by default on Mac OS 10.13 for x86_64 arch?
> If so, what did I miss, for there are symbols which must be exported, but absent in my compilation. I compile libcxxabi with following commands:
>  
> cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$BUILD_DIR/install -DLLVM_ENABLE_PROJECTS="libcxx;libcxxabi" $SRC_DIR
> ninja -j8
>  
> There is also bug, which seems to be related to this commit:
> https://bugs.llvm.org/show_bug.cgi?id=43749
>  
> Thanks!
> Stepan Dyatkovskiy
>  
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