Add package: gn

[thunder-coding]

TODOs:

• Add gn
• Test if it works
  Sample project compile well on aarch64 Android 11
• Create a termux_setup_gn script
  - [ ] Add a package that requires gn to build to test termux_setup_gn
  - [ ] Add package v8
  - [ ] nodejs link to shared v8

[thunder-coding]

Its not picking up the correct linker

cxx = aarch64-linux-android-clang++
ar = aarch64-linux-android-ar
ld = aarch64-linux-android-clang++

Notice -clang++ at the end instead of -ld

Same problem for other archs

EDIT: The gn gen.py was correct, it choose the correct ld. I have disabled building of gn_unittests which is basically unit tests which are useless to build (especially on CI)

[thunder-coding]

The compiled gn works well and for testing termux_setup_gn script, I will be adding the v8 package and make nodejs link to that v8. The v8 version will be kept roughly near to nodejs' in order to reduce number of patches.

Also while building Node.js 16, v8 seems to compile for wrong arch, so having shared v8 makes sense. See suhan-paradkar#8

@xeffyr I need your approval before working on this

[ghost]

Please make sure you have checked how termux_setup_golang or termux_setup_cmake work and adjust termux_setup_gn accordingly.

Specifically:

• Need integrity check of downloaded tarball. No matter whether it has been downloaded and checked previously. You need to verify it always.
• Do not re-install gn if it was already installed.

[ghost]

Fails at

ERROR at //BUILD.gn:5285:3: Assertion failed.
  assert(!is_component_build)
  ^-----

Possibly you need to add is_component_build=false.

[suhan-paradkar]

It requires libicu now??

[thunder-coding]

It requires libicu now??

It requires icu for i18n support

[hnmn]

ig target_os="android" be correct
Also target_os = ['android'] need in .gclient

[hnmn]

https://v8.dev/docs/cross-compile-arm

[thunder-coding]

I got it why v8 fails with shared libicu. libicu is missing pkg configs, I will push the fix soon.

And I got v8 building for x86_64. aarch64 build is going on.

If it passes, I will add patches for v8 which will be stealed from nodejs v8 patches

[suhan-paradkar]

Well.. 32 bit CPUs are facing few strange problems with gn..

[thunder-coding]

Well.. 32 bit CPUs are facing few strange problems with gn..

Probably that's due to some variables defined in scripts/build/termux_step_setup_toolchain.sh

Will try unsetting all of them after CI for aarch64 and x86_64 pass

[suhan-paradkar]

Well... About aarch64 build... Looks like the CI ran out of space...

[suhan-paradkar]

Same about x86_64 too...
You may need to free up space just like in rust...
See

termux-packages/.github/workflows/packages.yml

Line 111 in 30328a6

if grep -qP '^rust$' ./built_packages.txt ; then

[thunder-coding]

Now, that I have revised libicu to include pkg-config, I can confirm that V8 is looking for icu-i18n.pc at a really wrong place

https://github.com/chromium/chromium/blob/be8ee8535827682b07c0864c165eb9bca4005521/build/config/sysroot.gni#L20

Setting sysroot to /data/data/com.termux/files may help

The reason why it should be /data/data/com.termux/files instead of @TERMUX_PREFIX@ is https://github.com/chromium/chromium/blob/be8ee8535827682b07c0864c165eb9bca4005521/build/config/linux/pkg-config.py#L62

[thunder-coding]

https://github.com/chromium/chromium/blob/master/docs/clang.md

Seems like V8 uses a different clang binary than what we expect to compile stuff with.

I need some help with this since I don't have much knowledge about these compiler stuff

[ghost]

@thunder-coding The problem is --sysroot=../../../../../../../data/data/com.termux/files. Termux prefix is not valid compiler system root. There should be something like --sysroot=$TERMUX_STANDALONE_TOOLCHAIN/sysroot instead. Any headers and library paths of dependencies should be included through CFLAGS and LDFLAGS respectively.

[thunder-coding]

The input errors seem to be prominent even after setting sysroot to $TERMUX_STANDALONE_TOOLCHAIN/sysroot

[hnmn]

v8_enable_i18n_support=false try this

[thunder-coding]

v8_enable_i18n_support=false try this

This works, but at the cost of i18n support which is not desired.

[hnmn]

Can we just follow the official build guide for cross compiling v8?
Ig gn is looking for ndk at $v8_root/third_party

[thunder-coding]

Can we just follow the official build guide for cross compiling v8?
Ig gn is looking for ndk at $v8_root/third_party

I tried this approach and build fails with some GN import errors.

GN doesn't seem to respect $CC, $CXX and other environment variables. To cross compile for Android, target_os="android" needs ro be passed to GN args, but it fails as I said above. So I am gonna try providing a fake GCC instead.

[thunder-coding]

V8 seems to have a lot of problems compiling for Termux. Should I skip adding it? Atleast we can have GN for those who would like to have it...

[thunder-coding]

Okay, so I have removed all my commits for V8. I might try if I can get it building in another PR. And about the termux_setup_gn script, I am sure it will work, but for evey package that requires GN to build, we may need to patch respective BUILD.gn file of the same in order to make it choose correct build tools because GN doesn't by itself choose proper build tools from environment variables.