Clang in MSVC 2019

[blend2d]

Clang in MSVC 2019

[kobalicek]

Do you know how to pass these to clang-cl or it's a complete nonsense? With CMake it's really hard to avoid CMake defaults in this case, which turn exceptions on. This is definitely an issue that I would like to fix for both MSVC and Clang.

[martin31821]

You can pass -XClang $arbitraryOption to clang-cl as well as oclang (for mac os) to pass the default linux clang options.

[iryont]

martin31821 is right:

https://clang.llvm.org/docs/UsersManual.html#clang-cl

  -Xclang <arg>           Pass <arg> to the clang compiler

That should be trivial fix within cmake file.

[iryont]

Perhaps it might not be possible after all. Xclang does not appear to be working as I expected it to work. Some insight:

https://reviews.llvm.org/D53457

However, we are indeed lucky, the funny fact is that /clang: was actually implemented within clang-cl. So the following does the trick:

list(APPEND BLEND2D_PRIVATE_CFLAGS /clang:-fno-exceptions /clang:-fno-rtti /clang:-fno-math-errno)

Well, almost, since we are getting those warnings:

2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]
2>clang-cl : warning : argument unused during compilation: '-fno-exceptions' [-Wunused-command-line-argument]

The rest went away though.

[iryont]

Those flags are used during compilation:

/c /I"C:\X64-LIBS\BLEND2D\3RDPARTY\ASMJIT\SRC" /nologo /W4 /WX- /diagnostics:column /O2 /Ob2 /Oi /D WIN32 /D _WINDOWS /D NDEBUG /D BL_STATIC /D BL_BUILD_OPT_AVX2 /D ASMJIT_STATIC /D ASMJIT_NO_STDCXX /D "CMAKE_INTDIR=\"Release\"" /D _MBCS /EHsc /MD /GS- /fp:precise /GR- /Fo"BLEND2D.DIR\RELEASE\\" /Gd /TP -m64   -Zc:strictStrings -Zc:threadSafeInit- -volatile:iso /clang:-fno-exceptions /clang:-fno-rtti /clang:-fno-math-errno C:\X64-LIBS\BLEND2D\SRC\BLEND2D\API-NOCXX.CPP

Perhaps it ignores -fno-exceptions because of /EHsc which states:

If you use /EHs or /EHsc, then your catch(...) clause does not catch asynchronous structured exceptions. Access violations and managed System.Exception exceptions are not caught, and objects in scope when an asynchronous exception is generated are not destroyed even if the asynchronous exception is handled.

Perhaps instead we can use this:

  /GX-                    Disable exception handling
  /GX                     Enable exception handling

It's from LLVM UsersManual I did post before.

Edit:

I'm afraid not, it ignores it again just like no-exceptions.

[kobalicek]

I tried to fix all the warnings in 7f88f7b, however, the -fno-exceptions is not possible this way, so I have to find another way to set it. The warnings should be gone though.

[iryont]

Seems like it was taken care of. I suppose we might as well just close this issue? After all, it's pretty much resolved, unless of course you want to keep it open for the no-exceptions.

[kobalicek]

Yeah closing, I don't think I can fix the exception options today and it's not critical anyway :)