zig run/cc: recognize "-x language"

[motiejus]

This commit adds support for "-x language" for a couple of hand-picked supported languages. There is no reason the list of supported languages to not grow (e.g. add "c-header"), but I'd like to keep it small at the start.

Alternative 1

I first tried to add a new type "Language", and then add that to the CSourceFile. But oh boy what a change it turns out to be. So I am keeping myself tied to FileExt and see what you folks think.

Alternative 2

I tried adding Language: ?[]const u8 to CSourceFile. However, the language/ext, whatever we want to call it, still needs to be interpreted in the main loop: one kind of handling for source files, other kind of handling for everything else.

Test case

standalone.c

#include <iostream>

int main() {
    std::cout << "elho\n";
}

Compile and run:

$ ./zig run -x c++ -lc++ standalone.c
elho
$ ./zig c++ -x c++ standalone.c -o standalone && ./standalone
elho
$ .zig/x-lang/bin/zig cc -lc++ -x c++ standalone.c -o standalone  && ./standalone 
elho

Fixes #10915

[sagehane]

Does this PR work with build.zig too?

Something like:

    const exe = b.addExecutable("whatever", null);
    exe.addCSourceFiles(&.{
        "file1.c",
        "file2.c",
    }, &.{
        "-x c++",
    });

I know a bizarre project that only compiles when compiling Lua with a C++ compiler, and this would greatly help.

[N00byEdge]

wouldn't it be "-x", "c++"? For zig build it doesn't matter anyways, you can add cpp files aready afaik. @sagehane

[sagehane]

With the status-quo, my code above would be treated as C files because of their file extensions.
The issue isn't that I need C++ support; it's that I need to treat .c files as C++.

And the stdlib currently only has addCSourceFile to handle both C and C++, so there's no way to work around it afaik.

Edit: That said, the name of addCSouceFile is quite misleading tbh. But I doubt the solution is to make addCppSourceFile and a new function for every type of language Clang supports.

[motiejus]

cc @bfredl this is one of the prerequisites to compile neovim with zig cc.

[motiejus]

Does this PR work with build.zig too?

Something like:

    const exe = b.addExecutable("whatever", null);
    exe.addCSourceFiles(&.{
        "file1.c",
        "file2.c",
    }, &.{
        "-x c++",
    });

I know a bizarre project that only compiles when compiling Lua with a C++ compiler, and this would greatly help.

Not in this PR. That could be added, but I am not sure if the approach will be accepted in the first place. So I will not extend the scope yet.

[motiejus]

@sandhose's comment from #10915 (comment):

Can you try with #13544? I just added it to understand assembler-with-cpp.

@motiejus I built your PR and tried ; it fails with the following error:

$ /tmp/zig/build/stage3/bin/zig cc -target aarch64-linux-gnu -g -O0 -ffunction-sections -fdata-sections -fPIC -gdwarf-4 -fno-omit-frame
-pointer -Wall -Wextra -xassembler-with-cpp -DCFG_TARGET_OS_linux -DCFG_TARGET_ARCH_aarch64 -DCFG_TARGET_ENV_gnu -o /tmp/aarch_aapcs64.o -c src/arch/aar
ch_aapcs64.s
error: language 'assembly' is unsupported in this context

To reproduce:

git clone https://github.com/rust-lang/stacker
cd stacker/psm
zig cc -target aarch64-linux-gnu -g -O0 -ffunction-sections -fdata-sections -fPIC -gdwarf-4 -fno-omit-frame-pointer -Wall -Wextra -xassembler-with-cpp -DCFG_TARGET_OS_linux -DCFG_TARGET_ARCH_aarch64 -DCFG_TARGET_ENV_gnu -o /tmp/aarch_aapcs64.o -c src/arch/aarch_aapcs64.s

Thanks for providing the reproducible case. I've updated the PR and it no longer throws this error. Please test the current version.

[morenol]

@sandhose's comment from #10915 (comment):

Can you try with #13544? I just added it to understand assembler-with-cpp.

@motiejus I built your PR and tried ; it fails with the following error:

$ /tmp/zig/build/stage3/bin/zig cc -target aarch64-linux-gnu -g -O0 -ffunction-sections -fdata-sections -fPIC -gdwarf-4 -fno-omit-frame
-pointer -Wall -Wextra -xassembler-with-cpp -DCFG_TARGET_OS_linux -DCFG_TARGET_ARCH_aarch64 -DCFG_TARGET_ENV_gnu -o /tmp/aarch_aapcs64.o -c src/arch/aar
ch_aapcs64.s
error: language 'assembly' is unsupported in this context

To reproduce:

git clone https://github.com/rust-lang/stacker
cd stacker/psm
zig cc -target aarch64-linux-gnu -g -O0 -ffunction-sections -fdata-sections -fPIC -gdwarf-4 -fno-omit-frame-pointer -Wall -Wextra -xassembler-with-cpp -DCFG_TARGET_OS_linux -DCFG_TARGET_ARCH_aarch64 -DCFG_TARGET_ENV_gnu -o /tmp/aarch_aapcs64.o -c src/arch/aarch_aapcs64.s

Thanks for providing the reproducible case. I've updated the PR and it no longer throws this error. Please test the current version.

I build from this branch (macos) and it worked for me. Thanks! Looking forward to having a zig release with this

[kassane]

Is it intended to add support to -x c++-module too?

[motiejus]

Is it intended to add support to -x c++-module too?

Once this is merged, you are welcome to do so, should be relatively easy if you have a use case.

From my experience with working on this, it's difficult to add an extension without good understanding and example on how it will be used.

[andrewrk]

Excellent work. I see only one more thing to be done before merging, which is to add the new field ext to the cache hash in the addNonIncrementalStuffToCacheManifest (search for extra_flags).

[motiejus]

whoops, meant to comment in #14462.