[libc++][CI] Adds GCC trunk image. (#132271)

As discussed during the last monthly meeting we want to be able to test
the GCC development version in our CI, but we don't want to commit to
support this compiler version.

This adds the image to the CI Docker image. At the moment GCC-15 will
not pass the CI. Having it in the Docker image makes it possible to
validate fixes.

---------

Co-authored-by: Louis Dionne <[email protected]>
Co-authored-by: Hristo Hristov <[email protected]>

Author: 3 people

libcxx/utils/ci/Dockerfile

@@ -48,8 +48,8 @@ FROM $BASE_IMAGE AS builder-base
 ENV DEBIAN_FRONTEND=noninteractive
 
 # populated in the docker-compose file
-ARG GCC_LATEST_VERSION
-ENV GCC_LATEST_VERSION=${GCC_LATEST_VERSION}
+ARG GCC_HEAD_VERSION
+ENV GCC_HEAD_VERSION=${GCC_HEAD_VERSION}
 
 # populated in the docker-compose file
 ARG LLVM_HEAD_VERSION
@@ -147,12 +147,18 @@ RUN <<EOF
   set -e
   sudo git clone https://github.com/compiler-explorer/infra.git /tmp/ce-infra
   (cd /tmp/ce-infra && sudo make ce)
-  sudo /tmp/ce-infra/bin/ce_install install compilers/c++/x86/gcc $GCC_LATEST_VERSION.1.0
-  sudo /tmp/ce-infra/bin/ce_install install compilers/c++/x86/gcc $((GCC_LATEST_VERSION - 1)).1.0
-  sudo ln -s /opt/compiler-explorer/gcc-$GCC_LATEST_VERSION.1.0/bin/gcc /usr/bin/gcc-$GCC_LATEST_VERSION
-  sudo ln -s /opt/compiler-explorer/gcc-$GCC_LATEST_VERSION.1.0/bin/g++ /usr/bin/g++-$GCC_LATEST_VERSION
-  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_LATEST_VERSION - 1)).1.0/bin/gcc /usr/bin/gcc-$((GCC_LATEST_VERSION - 1))
-  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_LATEST_VERSION - 1)).1.0/bin/g++ /usr/bin/g++-$((GCC_LATEST_VERSION - 1))
+  # Current ToT, we do not guarantee any support in our support matrix.
+  sudo /tmp/ce-infra/bin/ce_install --enable nightly install compilers/c++/nightly/gcc trunk
+  sudo ln -s /opt/compiler-explorer/gcc-snapshot/bin/gcc /usr/bin/gcc-$GCC_HEAD_VERSION
+  sudo ln -s /opt/compiler-explorer/gcc-snapshot/bin/g++ /usr/bin/g++-$GCC_HEAD_VERSION
+  # The latest release.
+  sudo /tmp/ce-infra/bin/ce_install install compilers/c++/x86/gcc $((GCC_HEAD_VERSION - 1)).1.0
+  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_HEAD_VERSION - 1)).1.0/bin/gcc /usr/bin/gcc-$((GCC_HEAD_VERSION - 1))
+  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_HEAD_VERSION - 1)).1.0/bin/g++ /usr/bin/g++-$((GCC_HEAD_VERSION - 1))
+  # For CI transitions.
+  sudo /tmp/ce-infra/bin/ce_install install compilers/c++/x86/gcc $((GCC_HEAD_VERSION - 2)).1.0
+  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_HEAD_VERSION - 2)).1.0/bin/gcc /usr/bin/gcc-$((GCC_HEAD_VERSION - 2))
+  sudo ln -s /opt/compiler-explorer/gcc-$((GCC_HEAD_VERSION - 2)).1.0/bin/g++ /usr/bin/g++-$((GCC_HEAD_VERSION - 2))
   sudo rm -rf /tmp/ce-infra
 EOF
 

libcxx/utils/ci/docker-compose.yml

@@ -1,5 +1,5 @@
 x-versions: &compiler_versions
-  GCC_LATEST_VERSION: 14
+  GCC_HEAD_VERSION: 15
   LLVM_HEAD_VERSION: 21
 
 services: