[cfe-dev] New operator and some others don't have matching symbol names between clang and visual studio?

Thu Dec 26 00:35:19 PST 2013

You are correct that "-cxx-abi microsoft" with an appropriate win32 triple
is what I would consider ABI compatible.  However, reliance on that cc1
flag is ill-advised.  I (and to my knowledge all others involved in the
MSVC ABI effort) want the triple to implicitly control which ABI is
selected while removing the -cxx-abi flag altogether.

On Wed, Dec 25, 2013 at 11:39 PM, Astron B <boldaster at gmail.com> wrote:

> Hey David,
>
> Thanks a lot for the quick response. I had assumed this mode was already
> enabled since while using clang++.exe it said the target is i686-pc-win32
> rather than i686-pc-mingw. When calling the clang driver cc1 directly is
> "-cxx-abi" "microsoft" the argument that enables this mode? Thanks.
>
>
> On Thu, Dec 26, 2013 at 2:28 PM, David Majnemer <david.majnemer at gmail.com>wrote:
>
>> clang++.exe defaults to the mingw ABI.  It seems you want to use
>> clang-cl.exe, it uses the MSVC ABI.  Note that clang-cl.exe's argument
>> parsing is compatible with MSVC's cl.exe while clang++.exe is compatible
>> with gcc.
>>
>>
>> On Wed, Dec 25, 2013 at 10:03 PM, Astron B <boldaster at gmail.com> wrote:
>>
>>> Hey,
>>>
>>> I have an issue while trying to link some clang compiled code. When I
>>> compile my test dll with clang I get a new operator like this:
>>>
>>> __Znwj
>>>
>>> I guess this is conformant with GCC's naming.
>>>
>>> But when compiling with visual studio the new operator is:
>>>
>>> Searching libraries
>>>     Searching C:\Program Files (x86)\Microsoft Visual Studio
>>> 11.0\VC\LIB\MSVCRTD.lib:
>>>       Found __purecall
>>>         Referenced in ConsoleApplication2.obj
>>>         Loaded MSVCRTD.lib(MSVCR110D.dll)
>>>       Found "void * __cdecl operator new(unsigned int)" (??2 at YAPAXI@Z)
>>>         Referenced in ConsoleApplication2.obj
>>>         Loaded MSVCRTD.lib(MSVCR110D.dll)
>>>       Found "void __cdecl operator delete(void *)" (??3 at YAXPAX@Z)
>>>         Referenced in ConsoleApplication2.obj
>>>         Loaded MSVCRTD.lib(MSVCR110D.dll)
>>>
>>> I also noticed that with Clang I get a symbol for pure call catches
>>> called:
>>> ___cxa_pure_virtual
>>>
>>> I assume the __purecall above is the visual studio version.
>>>
>>> When I try to link the clang compiled object file using link.exe I get
>>> unresolved symbol errors because of this.
>>>
>>> F:\LLVM-fresh\vs11\bin\Debug>clang++ -c testdll.cpp -o testdll.o -v
>>> clang version 3.5 (trunk)
>>> Target: i686-pc-win32
>>> Thread model: posix
>>>  "F:\LLVM-fresh\vs11\bin\Debug\clang++.exe" -cc1 -triple i686-pc-win32
>>> -emit-obj
>>>  -mrelax-all -disable-free -main-file-name testdll.cpp
>>> -mrelocation-model static
>>>  -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases
>>> -target-cpu
>>> pentium4 -v -coverage-file "F:\\LLVM-fresh\\vs11\\bin\\Debug\\testdll.o"
>>> -resour
>>> ce-dir "F:\\LLVM-fresh\\vs11\\bin\\Debug\\..\\lib\\clang\\3.5"
>>> -internal-isystem
>>>  "F:\\LLVM-fresh\\vs11\\bin\\Debug\\..\\lib\\clang\\3.5\\include"
>>> -internal-isys
>>> tem "C:\\Program Files (x86)\\Microsoft Visual Studio 10.0\\VC\\INCLUDE"
>>> -intern
>>> al-isystem "C:\\Program Files (x86)\\Microsoft Visual Studio
>>> 10.0\\VC\\ATLMFC\\I
>>> NCLUDE" -internal-isystem "C:\\Program Files (x86)\\Microsoft
>>> SDKs\\Windows\\v7.
>>> 0A\\include" -std=c++11 -fdeprecated-macro -fdebug-compilation-dir
>>> "F:\\LLVM-fre
>>> sh\\vs11\\bin\\Debug" -ferror-limit 19 -fmessage-length 80
>>> -mstackrealign -fms-e
>>> xtensions -fms-compatibility -fmsc-version=1700
>>> -fdelayed-template-parsing -fobj
>>> c-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option
>>> -fcolor-di
>>> agnostics -vectorize-slp -o testdll.o -x c++ testdll.cpp
>>> clang -cc1 version 3.5 based upon LLVM 3.5svn default target
>>> i686-pc-win32
>>> #include "..." search starts here:
>>> #include <...> search starts here:
>>>  F:\LLVM-fresh\vs11\bin\Debug\..\lib\clang\3.5\include
>>>  C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE
>>>  C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\ATLMFC\INCLUDE
>>>  C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include
>>> End of search list.
>>>
>>> F:\LLVM-fresh\vs11\bin\Debug>nm testdll.o
>>> 00000000 t .text
>>> 00000000 t .text
>>> 00000001 a @feat.00
>>> 00000000 T __ZN7testOneC2Ev
>>>          U __Znwj
>>> 00000000 T _whatever
>>>
>>> F:\LLVM-fresh\vs11\bin\Debug>
>>>
>>>
>>> C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin>link /DLL
>>> /NOENTRY te
>>> stdll.o /VERBOSE
>>> Microsoft (R) Incremental Linker Version 11.00.50727.1
>>> Copyright (C) Microsoft Corporation.  All rights reserved.
>>>
>>>
>>> Starting pass 1
>>>
>>> Searching libraries
>>>
>>> Finished searching libraries
>>>
>>> Finished pass 1
>>>
>>> testdll.o : error LNK2019: unresolved external symbol __Znwj referenced
>>> in funct
>>> ion _whatever
>>> testdll.dll : fatal error LNK1120: 1 unresolved externals
>>>
>>>
>>>
>>> How can I get this to link? Thanks.
>>>
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>>
>>>
>>
>
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