5 ms·

The grandparent post refers to the fact that Zig ships with C, C++ library source that it lazily cross-builds (at least for linux, I don't recall how it solves

The grandparent post refers to the fact that Zig ships with C, C++ library source that it lazily cross-builds (at least for linux, I don't recall how it solves this problem for macOS or windows). And possibly it uses lld too? Since Zig ships with these, it makes the whole cross-build experience much smoother and less dependent on whether your host OS distribution includes packages for your desired target OS/architecture.

brabel 2y ago
Exactly. Zig tooling includes a linker, and that's also cross-platform. Zig can generate actual runnable executables that run anywhere from a single machine. As far as I can tell, D's DMD can cross compile but not link. I probably missed that before (actually, I think I was trying with LDC, I found the page where they document the process while searching for it just now: https://wiki.dlang.org/Cross-compiling_with_LDC https://wiki.dlang.org/Cross-compiling_with_LDC if you try those options, nothing works, at least from MacOS). I just tried and this only works with the -c option (compile, but not link): dmd -os=linux -c source/app.d Without `-c`: ``` Error: linker exited with status 1 cc app.o -o app -m64 -Xlinker -no_compact_unwind -L/Users/me/dlang/dmd-2.109.1/osx/bin/../lib -Xlinker -Bstatic -lphobos2 -Xlinker -Bdynamic -lpthread -lm (dmd-2.109.1) ``` I am sure Walter knows how to compile on one machine, then go to another machine and do the linking or whatever is needed. I know nothing about those, but with Zig I need not know anything other than which flag to use to cross compile. It's a huge difference. D should do that, otherwise it's just not competitive for people like me (I am just an average joe programmer who knows how to write code but has very little interest in learning how linkers work).
- wyldfire 2y ago
  > I am sure Walter knows how to compile on one machine, then go to another machine and do the linking or whatever is needed. Historically, you would or at least could get your compiler and linker from different vendors -- assembler, disassembler and other tools too. So it's normal/common for C compilers like gcc, clang, dmd to not be distributed like Zig is. But I would dare say that the way Zig is doing it is a great model for others. > go to another machine and do the linking BTW - if you use something like debian/ubuntu for development, they have compilers+linkers+binutils for several different architectures available to make cross-building without Zig at least a little bit easier.
  - kubkon 2y ago
    FYI, Zig is in the process of dropping dependence on lld on Linux and Windows; macOS uses Zig's own linker since roughly 2021 as far as I recall. Tracking issue for reference: https://github.com/ziglang/zig/issues/8726 https://github.com/ziglang/zig/issues/8726
- WalterBright 2y ago
  A cross-linker would be required for that to work. If you use a cross-linker with D, it should work.
  - brabel 2y ago
    Given Zig has one, it might actually be possible to delegate to that then? It would be awesome to have a post explaining how to do that :)
    - zellyn 2y ago
      The older “cross compiling Go with Zig” post might give a good start if you want to figure it out
      - brabel 2y ago
        I had a look at the post. It only shows how to tell the Go compiler how to use Zig as the C Compiler. In our case, what we need is to tell Zig to link the object files created by D. I've had a look and saw that Zig is still implementing the `ld` command, but there's already a `ld.ldd` command which might work if you know what magical options to use. I've tried to link my D object file but it can't find a whole lot of generated symbols, and a quick search online does not tell me where do I get those symbols from. That's always what happens when I try to do stuff with D that's not well documented. I tried this (used the dmd -v option to get the linker command): zig ld.lld -L/Users/me/dlang/dmd-2.109.1/osx/bin/../lib app.o Output: ``` ld.lld: error: undefined symbol: _d_assert_msg >>> referenced by myd/source/app.d >>> app.o:(_D4core8internal5newaa__T6makeAATAyaTiZQoFNaNeHQoiZSQByQBwQBq7AAShell) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format5write__T14formattedWriteTSQBm5stdio4File17LockingTextWriterTaTS3app__T9StringMapTiZQnZQDaFNfKQCqMxAaQBmZk) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format5write__T14formattedWriteTSQBm5stdio4File17LockingTextWriterTaTS3app__T9StringMapTiZQnZQDaFNfKQCqMxAaQBmZk) >>> referenced 27 more times ld.lld: error: undefined symbol: _aaLen >>> referenced by myd/source/app.d >>> app.o:(_D4core8internal5newaa__T6makeAATAyaTiZQoFNaNeHQoiZSQByQBwQBq7AAShell) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format8internal5write__T15formatValueImplTSQBw5stdio4File17LockingTextWriterTHiHAyaiTaZQClFNfKQCaQuMKxSQEeQEd4spec__T10FormatSpecTaZQpZv) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format8internal5write__T15formatValueImplTSQBw5stdio4File17LockingTextWriterTHAyaiTaZQCjFNfKQByQsMKxSQEcQEb4spec__T10FormatSpecTaZQpZv) ld.lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors) ``` Do you know how to get past that?

brabel 2y ago

Exactly. Zig tooling includes a linker, and that's also cross-platform. Zig can generate actual runnable executables that run anywhere from a single machine. As far as I can tell, D's DMD can cross compile but not link. I probably missed that before (actually, I think I was trying with LDC, I found the page where they document the process while searching for it just now: https://wiki.dlang.org/Cross-compiling_with_LDC https://wiki.dlang.org/Cross-compiling_with_LDC if you try those options, nothing works, at least from MacOS). I just tried and this only works with the -c option (compile, but not link): dmd -os=linux -c source/app.d Without `-c`: ``` Error: linker exited with status 1 cc app.o -o app -m64 -Xlinker -no_compact_unwind -L/Users/me/dlang/dmd-2.109.1/osx/bin/../lib -Xlinker -Bstatic -lphobos2 -Xlinker -Bdynamic -lpthread -lm (dmd-2.109.1) ``` I am sure Walter knows how to compile on one machine, then go to another machine and do the linking or whatever is needed. I know nothing about those, but with Zig I need not know anything other than which flag to use to cross compile. It's a huge difference. D should do that, otherwise it's just not competitive for people like me (I am just an average joe programmer who knows how to write code but has very little interest in learning how linkers work).

wyldfire 2y ago
> I am sure Walter knows how to compile on one machine, then go to another machine and do the linking or whatever is needed. Historically, you would or at least could get your compiler and linker from different vendors -- assembler, disassembler and other tools too. So it's normal/common for C compilers like gcc, clang, dmd to not be distributed like Zig is. But I would dare say that the way Zig is doing it is a great model for others. > go to another machine and do the linking BTW - if you use something like debian/ubuntu for development, they have compilers+linkers+binutils for several different architectures available to make cross-building without Zig at least a little bit easier.
- kubkon 2y ago
  FYI, Zig is in the process of dropping dependence on lld on Linux and Windows; macOS uses Zig's own linker since roughly 2021 as far as I recall. Tracking issue for reference: https://github.com/ziglang/zig/issues/8726 https://github.com/ziglang/zig/issues/8726
WalterBright 2y ago
A cross-linker would be required for that to work. If you use a cross-linker with D, it should work.
- brabel 2y ago
  Given Zig has one, it might actually be possible to delegate to that then? It would be awesome to have a post explaining how to do that :)
  - zellyn 2y ago
    The older “cross compiling Go with Zig” post might give a good start if you want to figure it out
    - brabel 2y ago
      I had a look at the post. It only shows how to tell the Go compiler how to use Zig as the C Compiler. In our case, what we need is to tell Zig to link the object files created by D. I've had a look and saw that Zig is still implementing the `ld` command, but there's already a `ld.ldd` command which might work if you know what magical options to use. I've tried to link my D object file but it can't find a whole lot of generated symbols, and a quick search online does not tell me where do I get those symbols from. That's always what happens when I try to do stuff with D that's not well documented. I tried this (used the dmd -v option to get the linker command): zig ld.lld -L/Users/me/dlang/dmd-2.109.1/osx/bin/../lib app.o Output: ``` ld.lld: error: undefined symbol: _d_assert_msg >>> referenced by myd/source/app.d >>> app.o:(_D4core8internal5newaa__T6makeAATAyaTiZQoFNaNeHQoiZSQByQBwQBq7AAShell) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format5write__T14formattedWriteTSQBm5stdio4File17LockingTextWriterTaTS3app__T9StringMapTiZQnZQDaFNfKQCqMxAaQBmZk) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format5write__T14formattedWriteTSQBm5stdio4File17LockingTextWriterTaTS3app__T9StringMapTiZQnZQDaFNfKQCqMxAaQBmZk) >>> referenced 27 more times ld.lld: error: undefined symbol: _aaLen >>> referenced by myd/source/app.d >>> app.o:(_D4core8internal5newaa__T6makeAATAyaTiZQoFNaNeHQoiZSQByQBwQBq7AAShell) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format8internal5write__T15formatValueImplTSQBw5stdio4File17LockingTextWriterTHiHAyaiTaZQClFNfKQCaQuMKxSQEeQEd4spec__T10FormatSpecTaZQpZv) >>> referenced by myd/source/app.d >>> app.o:(_D3std6format8internal5write__T15formatValueImplTSQBw5stdio4File17LockingTextWriterTHAyaiTaZQCjFNfKQByQsMKxSQEcQEb4spec__T10FormatSpecTaZQpZv) ld.lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors) ``` Do you know how to get past that?