Building LLVM on mac-arm64

[oxisto]

First attempt to build LLVM on mac-arm64. Not sure, if I understood the profile system correctly.

Closes #1091

[saudet]

Yes, the profiles need to be updated too. It's essentially the same as I did for JavaCPP itself in commit bytedeco/javacpp@87a6194.

[oxisto]

@saudet I might need your help on this one. I think I got the profiles correct now.

Do I need to change

javacpp-presets/llvm/cppbuild.sh

Lines 90 to 95 in fb4bba0

	macosx-*)
	$CMAKE -S ../llvm -B $LLVM_BUILD -DLLVM_CCACHE_BUILD=ON -DCMAKE_EXE_LINKER_FLAGS='-Wl,-rpath,@loader_path/' -DCMAKE_INSTALL_PREFIX=$INSTALL_PATH -DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_LINK_LLVM_DYLIB=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=all -DLLVM_ENABLE_LIBXML2=OFF -DLLVM_INCLUDE_TESTS=OFF -DLLVM_ENABLE_PROJECTS="$PROJECTS"
	make -C $LLVM_BUILD -j $MAKEJ
	make -C $LLVM_BUILD install > /dev/null
	cp $INSTALL_PATH/lib/LLVMPolly.so $INSTALL_PATH/lib/libLLVMPolly.so
	;;

this as well to split it up and pass -arch or is this taken care of on another level?

[oxisto]

@saudet I might need your help on this one. I think I got the profiles correct now.

Do I need to change

javacpp-presets/llvm/cppbuild.sh

Lines 90 to 95 in fb4bba0

	macosx-*)
	$CMAKE -S ../llvm -B $LLVM_BUILD -DLLVM_CCACHE_BUILD=ON -DCMAKE_EXE_LINKER_FLAGS='-Wl,-rpath,@loader_path/' -DCMAKE_INSTALL_PREFIX=$INSTALL_PATH -DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_LINK_LLVM_DYLIB=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=all -DLLVM_ENABLE_LIBXML2=OFF -DLLVM_INCLUDE_TESTS=OFF -DLLVM_ENABLE_PROJECTS="$PROJECTS"
	make -C $LLVM_BUILD -j $MAKEJ
	make -C $LLVM_BUILD install > /dev/null
	cp $INSTALL_PATH/lib/LLVMPolly.so $INSTALL_PATH/lib/libLLVMPolly.so
	;;

this as well to split it up and pass -arch or is this taken care of on another level?

I think I got now. Should hopefully run now.

[saudet]

At first glance, that looks alright, thanks!

For consistency though, let's add the macosx-arm64 lines before the ones for macosx-x86_64.

[oxisto]

At first glance, that looks alright, thanks!

For consistency though, let's add the macosx-arm64 lines before the ones for macosx-x86_64.

I can switch that, no problem.

There seems to be a build error on llvm when building for arm64 though :(

/bin/sh: ../../../../bin/clang-tblgen: Bad CPU type in executable
7079
[  8%] Building arm_cde.h...
7080
make[2]: *** [tools/clang/lib/Headers/arm_bf16.h] Error 126
7081
make[2]: *** Waiting for unfinished jobs....
7082
[INFO] ------------------------------------------------------------------------
7083
/bin/sh: ../../../../bin/clang-tblgen: Bad CPU type in executable

It looks like the target is still x86 :(

-- LLVM default target triple: x86_64-apple-darwin20.6.0
1923

[saudet]

Since we're cross compiling, we need to prebuild those tools for x86_64 first, as with linux-arm64:
https://github.com/bytedeco/javacpp-presets/blob/master/llvm/cppbuild.sh#L62-L75

[oxisto]

Since we're cross compiling, we need to prebuild those tools for x86_64 first, as with linux-arm64:
https://github.com/bytedeco/javacpp-presets/blob/master/llvm/cppbuild.sh#L62-L75

I added that step as well now and things seem to look good now on my x86 test machine.

[oxisto]

I am a bit lost why this still fails. It works fine on my Mac mini x86, it produces an arm64 binar without any errors.

[saudet]

Those binaries need to be built for x86_64, not arm64. Maybe your version of Mac comes with an emulator for arm64 binaries, but that's not the case of the machines running for GitHub Actions.

[oxisto]

Those binaries need to be built for x86_64, not arm64. Maybe your version of Mac comes with an emulator for arm64 binaries, but that's not the case of the machines running for GitHub Actions.

What was confusing me is that for the linux-arm64 example you referred my to the target triple and target arch was set to arm64, not x86_64.

[oxisto]

Looks like this finally compiled 🥳 As @saudet suggested, I will move the arm64 entries before the x86_64 ones - any other cleanup wanted? Is there any way to actually retrieve the build artefacts and check if they are in fact arm64?

[saudet]

After this gets merged, the snapshots will be available for download: http://bytedeco.org/builds/

Before we do that though, there are still a lot of places where arm64 is still after x86_64. Please update everything!

[oxisto]

After this gets merged, the snapshots will be available for download: http://bytedeco.org/builds/

Before we do that though, there are still a lot of places where arm64 is still after x86_64. Please update everything!

I was following the style of the individual files. For example in the cppbuild.sh, x86_64 was already placed before arm64 for Linux. Should I fix these already existing inconsistencies as well?

[saudet]

Right, some places have been a bit off like that, but don't worry about those. Just do the mac ones "right". Thanks!