Support for cross-compiling on Linux by universeindex · Pull Request #465 · smartcmd/MinecraftConsoles

universeindex · 2026-03-04T18:49:14Z

Description

I've implemented support for cross-compiling a Windows build on a Linux host using clang-cl. I added a toolchain file at cmake/LinuxCrosscompile.cmake that achieves this. I also modified many source files to not use backslashes in include statements (which error with clang-cl) and use case-sensitive paths (many Linux filesystems are case-sensitive, unlike NTFS, which causes errors). I avoided changing actual functionality as much as possible, so I hope this isn't too intrusive. Additionally I apologize for the messy commit messages, I hope this isn't a big issue, I have detailed all of the changes I made here.

Changes

Include statements use forward slashes instead of backslashes
Include statements reference files with correct capitalization
Added a CMake toolchain file for using clang-cl on Linux
Minecraft.Client/Xbox/MinecraftWindows.rc is not compiled on Linux, this causes errors otherwise, as it can't find the windows SDK and I am unsure how to specify the location here.
I also added documentation for building on Linux.

Previous Behavior

Running CMake on Linux would throw a hardcoded error stating that Linux isn't supported. When removed, and clang-cl is set to be used, many errors occur due to include paths using backslashes and inconsistent capitalization. The only way to build and run on Linux before is to use a Windows VM, and there is no way to get proper code completion on a Linux IDE.

Root Cause

Backslashes in include paths are supported on Windows, but not other systems, and NTFS is case-insensitive, so include paths do not have to match capitalization, also not on other systems.

New Behavior

The game now compiles and outputs a Windows binary on Linux using clang-cl.

Fix Implementation

See changes section

…ace all #inlcudes containing backslashes with forward slashes (not supported outside MSVC)

…e in miles sound system, probably the abi blowing up

universeindex · 2026-03-04T18:55:22Z

P.S. I tested building on Windows, which still works fine, so hopefully there shouldn't be any issues

universeindex · 2026-03-04T19:03:46Z

Most commits made to upstream will probably conflict with those by overwriting the includes I changed back with backslashes, but I'll be fixing those until this is merged

void2012 · 2026-03-04T19:07:09Z

Yes, I will be very happy to have clang-cl support and cross compilation support. Actually, clang-cl will be a test site for /fp:fast because it optimizes better than MSVC. Let me review this one.

void2012 · 2026-03-04T19:08:36Z

Have you tested it compiling with MSVC? Both msbuild and cmake. I hope this doesn't break the MSVC compilation.

universeindex · 2026-03-04T19:10:14Z

I tested CMake w/ visual studio generator on Windows (with MSVC) which worked fine, but I haven't tried the normal .sln yet. I can do that now, but it might be a minute, i'm working on a really slow machine currently

universeindex · 2026-03-04T19:40:30Z

works fine, compiles and runs w/ visual studio build ^

void2012 · 2026-03-04T19:42:55Z

Could you please tell, aside from #includes, what did you change? Reviewing that much files is pain.

universeindex · 2026-03-04T19:46:27Z

I did rewrite Minecraft.Client/iob_shim.asm in C++ as IobShim.cpp because I couldn't get MASM to work under Linux, but that's it aside from the includes I believe.

DwifteJB · 2026-03-04T19:47:40Z

can confirm does compile on linux w/ cmake

well done :)

void2012 · 2026-03-04T19:51:44Z

That asm file wasn't really an asm thing rather a MSVC linker hack and it appears we don't actually need that at all.

DwifteJB · 2026-03-04T20:01:27Z

cmake/LinuxCrosscompile.cmake

+set(CMAKE_C_COMPILER_FRONTEND_VARIANT MSVC)
+set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT MSVC)
+
+add_compile_options(/winsysroot /opt/msvc --target=x86_64-pc-windows-msvc -fms-compatibility -fms-extensions -fdelayed-template-parsing)


the cmake file assumes /opt/msvc whereas https://github.com/mstorsjo/msvc-wine recommends ~/my_msvc/opt/msvc

just a simple issue as you can syslink or run the msvc-wine installer as root & install to /opt/msvc

@universeindex

oh, good catch, i think i might set it to CMAKE_BINARY_DIR/msvc so users can symlink one instead, or if theres a way to set options of a toolchain file that would be best
will change soon, not home atm

msvc-wine sets itself in the path directory (although the user has to set this up manually through something like .zshrc)

could do something like

whereis msbuild

to determine the directory?

if it isn't set as CMAKE_MSVC_DIR

opened pr on your fork that fixes this & a clang error universeindex#1

void2012 · 2026-03-04T20:55:54Z

I think __iob_func should be implemented as __declspec(naked) + __asm.

…ot with explicit -imsvc paths

DwifteJB · 2026-03-04T21:26:55Z

I think __iob_func should be implemented as __declspec(naked) + __asm.

_declspec(naked) seems to not be working since __asm seems to have been dropped for x64 (if you want to use it you have to use a .asm file, like how 4J seems to have done it)

__attribute__((naked)) & __asm__() works however

DwifteJB · 2026-03-04T21:27:23Z

will need someone to test compiling on windows however

void2012 · 2026-03-04T21:30:15Z

I think __iob_func should be implemented as __declspec(naked) + __asm.

_declspec(naked) seems to not be working since __asm seems to have been dropped for x64 (if you want to use it you have to use a .asm file, like how 4J seems to have done it)

__attribute__((naked)) & __asm__() works however

Forgot about it that, as I am used to x86 development. Uncool, Microsoft. Anyway, maybe conditionally use the .asm file for MSVC assembler and .cpp with [[__gnu__::__naked__]] for Clang-cl?

DRAGONTOS · 2026-03-04T21:31:08Z

i dont seem to be able to compile this

universeindex · 2026-03-05T23:52:08Z

i've been trying for ages and I genuinely have no clue how to add a clang build option to msbuild, really sorry. it works fine in cmake but visual studio just isn't playing along. if someone else can figure it out thats great, but I give up

void2012 · 2026-03-05T23:56:35Z

Install Clang-cl with visual studio installer, add new configuration for a project, call it ClangRelease, set the toolchain from v145 to Clang-cl

universeindex · 2026-03-06T00:00:46Z

I get that, but my issue is that it's just not creating a new configuration. I select new and click ok then nothing happens, doesn't add the config at all
https://files.catbox.moe/ds1lvy.mp4

niansa · 2026-03-06T10:44:43Z

You can just use this: https://github.com/mstorsjo/msvc-wine
To install MSVC to /opt/msvc:

sudo mkdir /opt/msvc
sudo chown -R $USER /opt/msvc
./vsdownload.py --dest /opt/msvc
./install.sh /opt/msvc

Then add it to PATH:

export PATH="/opt/msvc/bin/x64:$PATH"

And then you can just use the Toolchain file and everything should work perfectly. This also adds a working rc executable to PATH, etc.

void2012 · 2026-03-06T10:46:16Z

Folks say msvc-wine doesn't work for them.

DwifteJB · 2026-03-06T10:46:24Z

You can just use this: https://github.com/mstorsjo/msvc-wine

To install MSVC to /opt/msvc:
sudo mkdir /opt/msvc

sudo chown -R $USER /opt/msvc

./vsdownload.py --dest /opt/msvc

./install.sh /opt/msvc
Then add it to PATH:
export PATH="/opt/msvc/bin/x64:$PATH"
And then you can just use the Toolchain file and everything should work perfectly. This also adds a working rc executable to PATH, etc.

... this is what this pull request is doing... 😭😭😭

niansa · 2026-03-06T10:46:51Z

Huh? It's working perfectly fine for me. This is exactly how I got this to work on my system.

DwifteJB · 2026-03-06T10:47:35Z

Folks say msvc-wine doesn't work for them.

they need lld installed which should probably be mentioned

niansa · 2026-03-06T10:47:38Z

... this is what this pull request is doing... 😭😭😭

Is there a script included that already does this? If so then ignore me I guess lol
I just saw people discussing llvm-rc which isn't actually needed if done this way.

DwifteJB · 2026-03-06T10:48:19Z

that's the issue i had at the very least before it started working, an ambiguous error due to no lld linker

niansa · 2026-03-06T10:48:44Z

they need lld installed which should probably be mentioned

Yes lld is needed.

Let me just create a fresh Debian Trixie Distrobox to figure out everything that is required.

DwifteJB · 2026-03-06T10:49:20Z

... this is what this pull request is doing... 😭😭😭

Is there a script included that already does this? If so then ignore me I guess lol

I just saw people discussing llvm-rc which isn't actually needed if done this way.

there's no script to install but it's mentioned in compile.md within the project, might be a good idea to use something like docker / nix so we can containerise the actual building so it works no matter what system (macos, linux, windows, etc)

DwifteJB · 2026-03-06T10:50:16Z

they need lld installed which should probably be mentioned

Yes lld is needed.

Let me just create a fresh Debian Trixie Distrobox to figure out everything that is required.

i tested with arch, all that's required is base-devel, cmake, gcc, ninja & lld from my knowledge (and obviously msvc-wine & wine)

niansa · 2026-03-06T10:52:08Z

Alright I'll put together a Dockerfile real quick then.

niansa · 2026-03-06T11:44:23Z

There are Dockerfiles already in the repo lol

Either way in case anyone can use it, here's a script I wrote for testing purposes:

# Fresh Debian Trixie install

dpkg --add-architecture i386
apt update
apt install wine wine32 wine64 msitools git python3 cmake ninja-build lld-19 llvm-19 clang-19

DISPLAY= wineboot

# MSVC install
(
    git clone https://github.com/mstorsjo/msvc-wine.git
    cd msvc-wine
    git checkout 32b504c63b869681cda6824a20e30b74cb718432

    mkdir /opt/msvc
    ./vsdownload.py --dest /opt/msvc --accept-license
    ./install.sh /opt/msvc

    ln -s /usr/bin/clang-cl{-19,}
    ln -s /usr/bin/lld-link{-19,}
)

# MSVC setup
export PATH="/opt/msvc/bin/x64:$PATH"

# Project build
(
    git clone https://github.com/universeindex/MinecraftConsoles.git --depth 1 --recursive
    cd MinecraftConsoles
    mkdir build
    cd build
    cmake .. -GNinja -DCMAKE_TOOLCHAIN_FILE=../cmake/LinuxCrosscompile.cmake
    ninja
)

niansa · 2026-03-06T11:48:14Z

I might try to get this to build using clang-cl with mingw 🤔
That would avoid a LOT of complications but probably introduces other complications on the way

universeindex · 2026-03-06T12:07:34Z

tried this, but i started to get many more strange errors, i think lce depends on msvc specific stdlib stuff
i think this system works fine, we just need to add clang-cl into the visual studio build and then this pr is done (hopefully)
later i could add scripts to automatically download the msvc toolchain, but due to the eula it would have to download the official packages and extract those, which requires the msitools package

niansa · 2026-03-06T12:18:40Z

Yeah, fuck this codebase lol... using backslashes in include paths is already insane enough
Depending on MSVC sucks, but the quality... who the HECK thought it'd be a good idea to using namespace std; in every single header file??

universeindex · 2026-03-06T12:20:03Z

God only knows

BlueishSapphire · 2026-03-06T18:05:57Z

Would it be reasonable to split this into multiple PRs? Converting backslashes to forward slashes and fixing the casing issues in #includes would be easy to split off into a new PR and merge it right now. It would also make developing on HEAD on linux a lot easier in the meantime while the rest of this PR is still being developed.

universeindex · 2026-03-06T18:31:45Z

good idea actually, didnt think of that
not sure how i would go about that now that all my changes are mangled together though.. probably I'll make a new branch on my fork and start from scratch, i used scripts to do the conversion anyways so it shouldn't be that hard
I'm not home now but i can gladly do that over the weekend, thanks for the idea

void2012 · 2026-03-06T18:33:11Z

Okay, screw the Visual Studio solution file, I can't add new configuration either. Let's add clang-cl as cmake only for now. Resolve the branch conflicts and imma merge this one.

universeindex · 2026-03-06T18:45:01Z

We love microslop <3
I'll see if i can fix merge conflicts soon but I am still a little busy at school right now, so sorry if it takes a few hours

BlueishSapphire · 2026-03-06T19:09:52Z

I can make a new branch and PR with the #include changes, I'll just have to run a couple sed scripts

universeindex · 2026-03-06T19:11:26Z

looks like void is ready to merge this existing one once i fix up merge conflicts though, so maybe not, sorry

DRAGONTOS · 2026-03-06T19:52:23Z

    ninja

this script made me possible to also compile this :3

AE70 · 2026-03-06T21:10:41Z

Since there's no updates, I fixed the conflicts and got this to work in one of the latest commit of upstream and can merge automatically as of speaking, PR the PR? https://github.com/AE70/MinecraftConsoles/tree/pr465 .

DRAGONTOS · 2026-03-06T21:34:54Z

Since there's no updates, I fixed the conflicts and got this to work in one of the latest commit of upstream and can merge automatically as of speaking, PR the PR? https://github.com/AE70/MinecraftConsoles/tree/pr465 .

it doesnt seem to have audio but that could be a upstream issue

AE70 · 2026-03-06T21:45:57Z

it doesnt seem to have audio but that could be a upstream issue

not upstream issue, need to fix that.

universeindex · 2026-03-07T00:02:46Z

was it one of my commits that broke audio? i never touched that, last i checked it was working, weird

universeindex added 9 commits March 3, 2026 13:07

Updated CMakeLists.txt to support cross-compiling on linux host, repl…

cbd8d4f

…ace all #inlcudes containing backslashes with forward slashes (not supported outside MSVC)

I am suffering

0234a3d

remove compile_commands.json

a544e96

Cross compilation working, does not actually run and crashes somewher…

bdeec50

…e in miles sound system, probably the abi blowing up

stuff

728f124

Fix merge conflicts

8434825

fix merge conflicts, build issues

620181f

update, merge upstream, fix conflicts (again)

e212021

fix other stuff

1dbfe11

Merge branch 'main' into main

746fe06

void2012 mentioned this pull request Mar 4, 2026

Implement Crossplatform (Linux, macOS, etc) support #460

Closed

Merge branch 'main' into main

b87774a

DwifteJB reviewed Mar 4, 2026

View reviewed changes

fix: auto-detect winsysroot from msbuild location & replace /winsysro…

bf31940

…ot with explicit -imsvc paths

fix: implement IobShim.cpp

ee78a74

Conversation

universeindex commented Mar 4, 2026

Description

Changes

Previous Behavior

Root Cause

New Behavior

Fix Implementation

Uh oh!

universeindex commented Mar 4, 2026

Uh oh!

universeindex commented Mar 4, 2026

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

universeindex commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

universeindex commented Mar 4, 2026

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

universeindex commented Mar 4, 2026

Uh oh!

DwifteJB commented Mar 4, 2026

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

DwifteJB Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

void2012 Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

universeindex Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

DwifteJB Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

DwifteJB Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

DwifteJB commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

DwifteJB commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

void2012 commented Mar 4, 2026

Uh oh!

DRAGONTOS commented Mar 4, 2026

Uh oh!

universeindex commented Mar 5, 2026

Uh oh!

void2012 commented Mar 5, 2026

Uh oh!

universeindex commented Mar 6, 2026

Uh oh!

niansa commented Mar 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

void2012 commented Mar 6, 2026

Uh oh!

DwifteJB commented Mar 6, 2026

Uh oh!

niansa commented Mar 6, 2026

Uh oh!

DwifteJB commented Mar 6, 2026

Uh oh!

niansa commented Mar 6, 2026

Uh oh!

DwifteJB commented Mar 6, 2026

Uh oh!

niansa commented Mar 6, 2026

universeindex commented Mar 4, 2026 •

edited

Loading

DwifteJB Mar 4, 2026 •

edited

Loading

DwifteJB commented Mar 4, 2026 •

edited

Loading

DwifteJB commented Mar 4, 2026 •

edited

Loading

niansa commented Mar 6, 2026 •

edited

Loading

niansa commented Mar 6, 2026 •

edited

Loading

niansa commented Mar 6, 2026 •

edited

Loading

AE70 commented Mar 6, 2026 •

edited

Loading