Added missing include file <optional>

[martinwinter-huawei]

There is an include file (<optional>) missing (in AzslcCodeEmissionMutator.h) when trying to build on Linux. The compiler used is gcc 12.1.0.

[siliconvoodoo]

The problem I believe, is that this wouldn't build on MacOS since they have an ancient stdlib. Maybe this is finally solved idk, but mac environment is the reason why there is src/external/tiny/optional.h in the first place. It'd be nice if a test build on mac can be attempted before merging.

bests

[martinwinter-huawei]

Unfortunately, I cannot test on Mac, but I changed the new commit such that it takes the proper stl libraries for both Windows and Linux and leaves Mac as is.

[jeremyong-az]

AFAICT, Linux should have included the 3rd party optional lib here instead of std::optional. Can you include the compile errors you were seeing on Linux?

[delanyinspiron6400]

AFAICT, Linux should have included the 3rd party optional lib here instead of std::optional. Can you include the compile errors you were seeing on Linux?

At the moment, src/AzslcCodeEmissionMutator.h uses std::optional instead of just optional. If I change this to optional, i.e. such that Linux now uses tiny/optional, I get the following errors:

• src/AzslcEmitter.cpp -> passing argument discards qualifiers, need to add const to the assert_value method in external/tiny/optional.h
• src/Texture2DMSto2DCodeMutator.cpp -> optional has no member named emplace, since that is not implemented in external/tiny/optional.h

If I add an implementation to external/tiny/optional.h for emplace and fix the method, then it also compiles.

What is now the preferred way? Letting Linux also use the proper stl or fixing the external package?

[jeremyong-az]

I believe we can actually just remove the STL workarounds. @siliconvoodoo and @galibzon may have insight here but I believe they were added initially due to a lack of complete compiler support on Linux and Apple Clang.

[martinwinter-huawei]

I believe we can actually just remove the STL workarounds. @siliconvoodoo and @galibzon may have insight here but I believe they were added initially due to a lack of complete compiler support on Linux and Apple Clang.

That would certainly be the cleanest option. Especially since optional was added with C++17, hence lacking support of a compiler for such a feature should not be an issue of azslc, but should result in upgrading the compiler.

[siliconvoodoo]

Yes we can, and should. It was for XCode9.

[martinwinter-huawei]

Yes we can, and should. It was for XCode9.

The new commit upgraded both variant and optional to the proper STL implementations.

[jeremyong-az]

Looks a lot cleaner thanks!

[siliconvoodoo]

Seems that we're getting an error on Mac, from Jackson Brendan report:

In file included from /Users/breja/github/AZSLc/src/StdUtils.h:29:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk/usr/include/c++/v1/variant:506:12: error: address of overloaded function '__dispatch' does not match required type 'const
      AZ::ShaderCompiler::TokensLocation (std::__variant_detail::__visitation::__variant::__value_visitor<AZ::ShaderCompiler::GetDefinitionNodeTokensLocation_Visitor> &&, const std::__variant_detail::__base<std::__variant_detail::_Trait::_Available,
      std::monostate, AZ::ShaderCompiler::VarInfo, AZ::ShaderCompiler::FunctionInfo, AZ::ShaderCompiler::OverloadSetInfo, AZ::ShaderCompiler::ClassInfo, AZ::ShaderCompiler::SRGInfo, AZ::ShaderCompiler::TypeRefInfo, AZ::ShaderCompiler::TypeAliasInfo> &)'
    return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~