How to integrate a gcc patch in riscv-none-elf-gcc-xpack ?

[bvernoux]

A contributor David Carne (@davidcarne) have created the patch gcc-12.2.0-riscv-wch-fast-interrupt.patch to add support of "WCH-Interrupt-fast" for WCH WCH56x(and potentially other WCH RISC-V MCU)

• This patch has been tested with https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/tag/v12.2.0-1.1

This patch work fine (see the toolchain pre-built with this patch https://hydrabus.com/hydrausb3_toolchain)
So far I have not found how to integrate it (in a clean way) with riscv-none-elf-gcc-xpack (My workaround is to patch the Work/cache/gcc-12.2.0.tar.xz with this patch)
Does anyone could help to integrate that patch ?

[ilg-ul]

If you want only to integrate the patch into your local build, there is a mechanism to apply a patch after the archive is downloaded. The patch must be located in the patches folder, and have a specific name, including the version.

If you would like to have the patch included in this distribution, things are more complicated, you have to contribute the patches to GNU GCC, and after the next GCC is released, they'll be in the xPack too.

[bvernoux]

I would like both in fact

1. Short term to have the procedure to put the patch in the paches folder (which one and with which exact name and format ?)
   • To have also a way to rebuild it without using Docker if possible (on a Ubuntu LTS distribution for different target at least Linux & Windows)
2. Mid/Long term to have the patch included in GNU GCC if you can help on that you are welcome

[ilg-ul]

Identify the function that downloads and extracts the gcc sources and somewhere there you should identify a variable which holds the patch name.

Please note that the build scripts will shortly be updated to a new version of the build environment.

For contributing the patch to GNU, I suggest you first discuss the issues with the RISC-V GCC maintainers, I am not involved in development, I'm just compiling the sources.

[bvernoux]

I have tried to build it with your details but it was not "Applying" the patch (the build was fine but without applying the patch on gcc source, checked with source code/deploy files vs my reference patch applied by hand)

rm -rf ${HOME}/Work/riscv-none-elf-gcc-xpack.git; \
git clone \
  --branch v12.2.0-1.1 \
  https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack.git \
  ${HOME}/Work/riscv-none-elf-gcc-xpack.git; \
git -C ${HOME}/Work/riscv-none-elf-gcc-xpack.git submodule update --init --recursive

cp ${HOME}/gcc-12.2.0-riscv-wch-fast-interrupt.patch ${HOME}/Work/riscv-none-elf-gcc-xpack.git/patches/gcc-12.2.0.patch.diff

bash ${HOME}/Work/riscv-none-elf-gcc-xpack.git/scripts/helper/build.sh preload-images
docker images
docker system prune --force

screen -S arm
sudo rm -rf ~/Work/riscv-none-elf-gcc-*-*
bash ${HOME}/Work/riscv-none-elf-gcc-xpack.git/scripts/helper/build.sh --develop --disable-tests --disable-multilib --linux64 --win64

[ilg-ul]

Are you sure you have a patches/gcc-12.2.0.patch.diff file?

In common-versions-source.sh add a set -x before calling the download_cross_gcc function and an exit 1 after it, clean everything and rerun. This should give you a better picture of what is happening.

[bvernoux]

I confirm I have ~/Work/riscv-none-elf-gcc-xpack.git/patches/gcc-12.2.0.patch.diff (file size is 4083 bytes)
I obtain following log:

+ echo '[tar -x' -f /Host/home/ben/Work/cache/gcc-12.2.0.tar.xz '--no-same-owner]'
[tar -x -f /Host/home/ben/Work/cache/gcc-12.2.0.tar.xz --no-same-owner]
+ tar -x -f /Host/home/ben/Work/cache/gcc-12.2.0.tar.xz --no-same-owner
+ '[' 3 -ge 3 ']'
+ cd gcc-12.2.0
+ do_patch ''
+ '[' '!' -z '' ']'
+ chmod -R +w gcc-12.2.0
+ local with_update_config_sub=
+ '[' '' == y ']'
+ exit 1

Which confirm the do_patch is applied on empty file instead of expected gcc-12.2.0.patch.diff

I have understood the issue there was a missing
GCC_PATCH_FILE_NAME="gcc-${GCC_VERSION}.patch.diff" just before the 1st download_cross_gcc

[ilg-ul]

Oops! Yes, the variable must be defined before the function call.

[bvernoux]

Thanks for your help