[libcxx-commits] [libcxx] r347399 - [libcxx] Mark stray symbols as hidden to try and fix the build

Tue Nov 27 10:46:38 PST 2018

Okay, thanks for the clarifications. Just make sure you're using the CMake option _LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT if you're building your own libc++. This will make sure that _LIBCPP_HIDE_FROM_ABI_PER_TU is always defined for anyone using your build of libc++.

Louis

> On Nov 27, 2018, at 13:35, Erik van der Poel <erikv at google.com> wrote:
> 
> Yes, we had a number of programs with a few very large stack frames, and this setting (based on Louis' great work) solved that particular problem.
> 
> On Tue, Nov 27, 2018 at 10:02 AM Jordan Rupprecht <rupprecht at google.com <mailto:rupprecht at google.com>> wrote:
> I'm not really sure why; I was just the lucky build cop and started seeing failures in that area :)
> 
> Fortunately Erik helped and suggested "_LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT:BOOL=ON" as a fix. The only context I can pull up is this: http://lists.llvm.org/pipermail/cfe-dev/2018-August/059156.html <http://lists.llvm.org/pipermail/cfe-dev/2018-August/059156.html>. Looks like we were hitting stack overflows without it.
> 
> On Wed, Nov 21, 2018 at 9:34 AM Benjamin Kramer <benny.kra at gmail.com <mailto:benny.kra at gmail.com>> wrote:
> We are defining _LIBCPP_HIDE_FROM_ABI_PER_TU in our libc++ build. I don't know why though.
> 
> Jordan, do you remember why we need that flag?
> 
> On Wed, Nov 21, 2018 at 6:30 PM Louis Dionne <ldionne at apple.com <mailto:ldionne at apple.com>> wrote:
> Thanks!
> 
> The problem is, as the error says, that I did not apply the attribute to the first declaration of that operator+. I missed it because we have this frustrating habit of declaring and defining heavily templated functions separately.
> 
> Also, how come are you using internal_linkage? Are you defining _LIBCPP_HIDE_FROM_ABI_PER_TU, and if so, why? Just trying to gather some user input.
> 
> Louis
> 
>> On Nov 21, 2018, at 12:21, Benjamin Kramer <benny.kra at gmail.com <mailto:benny.kra at gmail.com>> wrote:
>> 
>> I'm still seeing things like
>> 
>> In file included from llvm/projects/libcxx/src/ios.cpp:12:
>> In file included from llvm/projects/libcxx/include/ios:216:
>> In file included from llvm/projects/libcxx/include/__locale:15:
>> llvm/projects/libcxx/include/string:4041:1: error: 'internal_linkage' attribute does not appear on the first declaration of 'operator+'
>> operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
>> ^
>> llvm/projects/libcxx/include/string:584:1: note: previous definition is here
>> operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
>> ^
>> 
>> Any idea what's going on?
>> 
>> On Wed, Nov 21, 2018 at 6:03 PM Louis Dionne via libcxx-commits <libcxx-commits at lists.llvm.org <mailto:libcxx-commits at lists.llvm.org>> wrote:
>> 
>> 
>> 
>> ---------- Forwarded message ----------
>> From: Louis Dionne <ldionne at apple.com <mailto:ldionne at apple.com>>
>> To: libcxx-commits at lists.llvm.org <mailto:libcxx-commits at lists.llvm.org>
>> Cc: 
>> Bcc: 
>> Date: Wed, 21 Nov 2018 17:00:52 -0000
>> Subject: [libcxx] r347399 - [libcxx] Mark stray symbols as hidden to try and fix the build
>> Author: ldionne
>> Date: Wed Nov 21 09:00:52 2018
>> New Revision: 347399
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=347399&view=rev <http://llvm.org/viewvc/llvm-project?rev=347399&view=rev>
>> Log:
>> [libcxx] Mark stray symbols as hidden to try and fix the build
>> 
>> r347395 changed the ABI list on Linux, but two of those symbols are still
>> being exported from the shared object:
>> 
>>     _ZSt18make_exception_ptrINSt3__112future_errorEESt13exception_ptrT_
>>     _ZNSt3__1plIcNS_11char_traitsIcEENS_9allocatorIcEEEENS_12basic_stringIT_T0_T1_EERKS9_PKS6_
>> 
>> This commit makes sure those symbols are not exported, as they should be.
>> 
>> Modified:
>>     libcxx/trunk/include/exception
>>     libcxx/trunk/include/string
>> 
>> Modified: libcxx/trunk/include/exception
>> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/exception?rev=347399&r1=347398&r2=347399&view=diff <http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/exception?rev=347399&r1=347398&r2=347399&view=diff>
>> ==============================================================================
>> --- libcxx/trunk/include/exception (original)
>> +++ libcxx/trunk/include/exception Wed Nov 21 09:00:52 2018
>> @@ -164,7 +164,7 @@ public:
>>  };
>> 
>>  template<class _Ep>
>> -exception_ptr
>> +_LIBCPP_INLINE_VISIBILITY exception_ptr
>>  make_exception_ptr(_Ep __e) _NOEXCEPT
>>  {
>>  #ifndef _LIBCPP_NO_EXCEPTIONS
>> @@ -223,7 +223,7 @@ _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void r
>>  template <class _E> void *__GetExceptionInfo(_E);
>> 
>>  template<class _Ep>
>> -exception_ptr
>> +_LIBCPP_INLINE_VISIBILITY exception_ptr
>>  make_exception_ptr(_Ep __e) _NOEXCEPT
>>  {
>>    return __copy_exception_ptr(_VSTD::addressof(__e), __GetExceptionInfo(__e));
>> 
>> Modified: libcxx/trunk/include/string
>> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/string?rev=347399&r1=347398&r2=347399&view=diff <http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/string?rev=347399&r1=347398&r2=347399&view=diff>
>> ==============================================================================
>> --- libcxx/trunk/include/string (original)
>> +++ libcxx/trunk/include/string Wed Nov 21 09:00:52 2018
>> @@ -4036,7 +4036,7 @@ operator+(_CharT __lhs, const basic_stri
>>  }
>> 
>>  template<class _CharT, class _Traits, class _Allocator>
>> -_LIBCPP_INLINE_VISIBILITY
>> +inline _LIBCPP_INLINE_VISIBILITY
>>  basic_string<_CharT, _Traits, _Allocator>
>>  operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
>>  {
>> 
>> 
>> 
>> 
>> 
>> ---------- Forwarded message ----------
>> From: Louis Dionne via libcxx-commits <libcxx-commits at lists.llvm.org <mailto:libcxx-commits at lists.llvm.org>>
>> To: libcxx-commits at lists.llvm.org <mailto:libcxx-commits at lists.llvm.org>
>> Cc: 
>> Bcc: 
>> Date: Wed, 21 Nov 2018 09:00:53 -0800 (PST)
>> Subject: [libcxx-commits] [libcxx] r347399 - [libcxx] Mark stray symbols as hidden to try and fix the build
>> _______________________________________________
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