Tracking issue for Windows ARM64 support

[dennisameling]

There's been a discussion about Windows ARM64 support here: #3021

I made a discussion comment there to keep track of the outstanding tasks to get basic ARM64 support to Git for Windows. However, @Alovchin91 informed me via Twitter that it was hard to keep track of the progress that way, requesting a dedicated issue. So here it is 😊

Open tasks for basic ARM64 support:

• ✔️ Enable compiling Git for Windows (git.exe etc.) natively for arm64 Windows arm64 support #2915 (comment)
• ✔️ Fix double .exe suffix in CMake generated build Fix double .exe suffixes in CMakeLists.txt  #2966
• ✔️ Include vcpkg DLLs in CMake build cmake(install): include vcpkg dlls #2971
• ✔️ Add ARM64 to /etc/profile added MSYSTEM=ARM64 case in /etc/profile git-sdk-32#6
• ✔️ Update /etc/profile in git-extra.install.in Start support for MSYSTEM=ARM64 build-extra#321
• ✔️ Modify git-wrapper in mingw32 to use the native git.exe, set MSYSTEM=ARM64, etc. Add arm64 support to git-wrapper MINGW-packages#44
• ✔️ Create portable version of ARM64 Git for Windows portable: add arm64 artifact option build-extra#323
• ✔️ Create MinGit package for ARM64 Git for Windows mingit: add arm64 artifact option build-extra#324
• ✔️ Create archive package for ARM64 Git for Windows archive: add arm64 artifact option build-extra#325
• ✔️ Create an installer for ARM64 installer: add arm64 artifact option build-extra#326
• ✔️ Add ARM64 artifacts to CI git-artifacts: add ARM64 artifacts #3017
• ✔️ Update Inno Setup installer in preparation for installing Git for Windows ARM64 to the 64-bit Program Files folder installer: Update Inno Setup from 5.6.1 to 6.1.2 build-extra#330
• ✔️ Create logic for ARM64 in Inno Setup installer, so that Git will be installed in the 64-bit Program Files folder installer: add 64-bit support for ARM64 build-extra#333
• ✔️ Fix Git Credential Manager Core (necessary for git push etc.) by referencing it from the mingw32 directory Git Credential Manager Core missing in ARM64 libexec folder #3015
• ✔️ Decrease the size of the ARM64 artifacts significantly Assorted fixes/enhancements for the git-artifacts workflow #3053
• ✔️ Fix issue where system-wide gitconfig can't be read ARM64: cannot read/write system gitconfig  #3071
• ✔️ Fix bug where cmd\git.exe is crashing when arm64/bin folder is present cmd\git.exe crashing when ARM64 folder is present in Git installation (git-wrapper) #3083
• ✔️ Fix issue with Git Credential Manager Core on ARM64 git-artifacts: Update ARM64 GCM Core workaround #3085
• ❓ Update Azure DevOps pipeline?
• ✔️ Update the daily "Git for Windows update check" for ARM64: git update-git-for-windows: download ARM64 Git for Windows if applicable build-extra#340
• ✔️ git --version --build-options returns AMD64 as the CPU cmake(): allow setting HOST_CPU for cross-compilation #3327
• Visual C++ for ARM64 needs to be installed, due to us using MSVC for the ARM64 builds. We can either include that in the installer or statically build (if possible)
• Documentation using --help (example: git log --help) doesn't work since Git looks for docs in the wrong location

Thanks to the changes that we did in the last few days, there's now a fully working build of Git for Windows ARM64.

Test build for ARM64 users, built on March 12, 2021: https://github.com/dennisameling/git/releases/tag/v2.31.0-rc2.windows.2

I think we're pretty much ready to publish a beta version of Git for Windows ARM64! @dscho what do you think? Please let me know if I missed something in the list above.

[dscho]

I'm a bit focused on making sure that the v2.31.0 release goes smoothly, and will be happy to pay more attention to the ARM64 side of things after that release is out (which will probably happen Tuesday or Wednesday this coming week).

[Alovchin91]

Hi @dennisameling ,

Thanks for your wonderful work! ❤️ Have been using MinGit lately (which is a 💎 by itself) and it works great on my SPX!

One thing I just found:

C:\Projects\rustup>git log --help
fatal: 'C:/MinGit/arm64/share/doc/git-doc': not a documentation directory.

While MinGit doesn't seem to contain git-doc anyway, what caught my attention is that git.exe tries to search for documentation in the arm64 directory, while docs seem to still be in mingw32.

Could you please check on your side, on a complete Git setup? Thanks a lot! 😃

[dscho]

The documentation is not built as part of the CMake-based build. It will take quite some work to implement that. @Alovchin91 that's your chance to get involved! 😉

[Alovchin91]

@dscho I would be happy to help, but right now my capacity is extremely limited unfortunately and I have never had any proper experience with Cmake.

But wouldn't it be enough to point Git.exe from arm64 folder to the documentation in mingw32? 🤔

[dscho]

But wouldn't it be enough to point Git.exe from arm64 folder to the documentation in mingw32? 🤔

Not really, because the build configuration may differ in more than just the CPU architecture, even in ways affecting how/what parts of the documentation are compiled.

[Alovchin91]

Hmm, I think right now my concern is mostly about where does arm64 version look for docs in a full installer-based version of Git 🤔

I saw that it's also absent from the "normal" mingw32 MinGit build, so I suppose missing docs in those builds is not arm64 specific issue.

[dscho]

Right, documentation is excluded from MinGit builds.

But looking for the documentation in the wrong location, just because there is no documentation in the correct location, isn't a solution for the non-MinGit flavors of Git for Windows, either ;-)

[Alovchin91]

Ah, right, now I get your point 😁 For some reason I thought that the most part of the tools are redirected to mingw32 folder and arm64 only contains wrappers or helpers 😅

[dscho]

Thanks to @dennisameling tireless work, the Git executables are built for Windows/ARM64. The i686 version of the MINGW tools we're still relying on are things like curl.exe, but we do include all of the i686 Git executables at the moment, too.

[dennisameling]

Can confirm the help docs are only present in mingw32\share\doc\git-doc on a full installation and not in arm64\share\doc\git-doc.

The help function looks at GIT_HTML_PATH to find the help docs:

git/builtin/help.c

Lines 464 to 482 in 959b2f0

	static void get_html_page_path(struct strbuf *page_path, const char *page)
	{
	struct stat st;
	char *to_free = NULL;
	if (!html_path)
	html_path = to_free = system_path(GIT_HTML_PATH);
	/* Check that we have a git documentation directory. */
	if (!strstr(html_path, "://")) {
	if (stat(mkpath("%s/git.html", html_path), &st)
	|| !S_ISREG(st.st_mode))
	die("'%s': not a documentation directory.", html_path);
	}
	strbuf_init(page_path, 0);
	strbuf_addf(page_path, "%s/%s.html", html_path, page);
	free(to_free);
	}

This is defined in the CMake file:

git/contrib/buildsystems/CMakeLists.txt

Lines 206 to 217 in 959b2f0

	add_compile_definitions(PAGER_ENV="LESS=FRX LV=-c"
	GIT_EXEC_PATH="libexec/git-core"
	GIT_LOCALE_PATH="share/locale"
	GIT_MAN_PATH="share/man"
	GIT_INFO_PATH="share/info"
	GIT_HTML_PATH="share/doc/git-doc"
	DEFAULT_HELP_FORMAT="html"
	DEFAULT_GIT_TEMPLATE_DIR="share/git-core/templates"
	GIT_VERSION="${PROJECT_VERSION}.GIT"
	GIT_USER_AGENT="git/${PROJECT_VERSION}.GIT"
	BINDIR="bin"
	GIT_BUILT_FROM_COMMIT="")

@dscho would you be okay with a clause in the CMake file for Win ARM64 that sets GIT_HTML_PATH to ../mingw32/share/doc/git-doc for the time being? We can leverage the already available CMAKE_GENERATOR_PLATFORM for that logic.

[dscho]

would you be okay with a clause in the CMake file for Win ARM64 that sets GIT_HTML_PATH to ../mingw32/share/doc/git-doc for the time being?

I wonder how much work it would be to optionally use asciidoctor or asciidoc, if configured. These lines describe how asciidoc is called: https://github.com/git/git/blob/v2.31.0/Documentation/Makefile#L125-L133 And these describe how asciidoctor would be called instead: https://github.com/git/git/blob/v2.31.0/Documentation/Makefile#L179-L190

[dennisameling]

I wonder how much work it would be to optionally use asciidoctor or asciidoc, if configured.

Will have a look in the coming days.

Just created a PR for 64-bit ARM64 installer support: git-for-windows/build-extra#333

[dennisameling]

@dscho now that the 64-bit ARM64 installer PR has been merged, do you think we're ready to release a beta build of Git for Windows ARM64? I'm happy to look into the docs thing with asciidoctor and asciidoc mentioned above, but will only have time for that after May 7 due to work responsibilities and a break 😊 Thanks in advance!

[rimrul]

Check if the daily "Git for Windows update check" works correctly on ARM64

It'll probably run daily and check for updates, but when it detects an update, it'll try to download and install the x86 installer.