[llvm] [Github] Add libc container (PR #181434)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/181434

This will let us run the libc full build tests inside of a container which means that we have same time by not having to install dependencies on every run in addition to not running into issues due to dependencies failing to install particularly around LLVM releases with the llvm.sh script.

>From ad9fe40cbb5abdc28555cc508e3123e26b45be19 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Fri, 13 Feb 2026 23:20:20 +0000
Subject: [PATCH] [Github] Add libc container

This will let us run the libc full build tests inside of a container
which means that we have same time by not having to install dependencies
on every run in addition to not running into issues due to dependencies
failing to install particularly around LLVM releases with the llvm.sh
script.
---
 .github/workflows/build-libc-container.yml   | 53 ++++++++++++++++++++
 .github/workflows/containers/libc/Dockerfile | 24 +++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 .github/workflows/build-libc-container.yml
 create mode 100644 .github/workflows/containers/libc/Dockerfile

diff --git a/.github/workflows/build-libc-container.yml b/.github/workflows/build-libc-container.yml
new file mode 100644
index 0000000000000..a6a0f34860831
--- /dev/null
+++ b/.github/workflows/build-libc-container.yml
@@ -0,0 +1,53 @@
+name: Build libc Container
+
+permissions:
+  contents: read
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - .github/workflows/build-libc-container.yml
+      - '.github/workflows/containers/libc/**'
+  pull_request:
+    paths:
+      - .github/workflows/build-libc-container.yml
+      - '.github/workflows/containers/libc/**'
+
+jobs:
+  build-libc-container:
+    name: Build libc container
+    if: github.repository_owner == 'llvm'
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout LLVM
+        uses: actions/checkout at 8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout: |
+            .github/workflows/containers/libc/
+            .github/actions/build-container
+      - name: Build Container
+        uses: ./.github/actions/build-container
+        with:
+          container-name: libc-ubuntu-24.04
+          dockerfile: .github/workflows/containers/libc/Dockerfile
+          target: ''
+          test-command: ${{ matrix.test-command }}
+  push-libc-container:
+    if: github.event_name == 'push'
+    needs:
+      - build-libc-container
+    permissions:
+      packages: write
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout LLVM
+        uses: actions/checkout at 8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout: |
+            .github/actions/push-container
+
+      - uses: ./.github/actions/push-container
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/containers/libc/Dockerfile b/.github/workflows/containers/libc/Dockerfile
new file mode 100644
index 0000000000000..78319d81a2ad0
--- /dev/null
+++ b/.github/workflows/containers/libc/Dockerfile
@@ -0,0 +1,24 @@
+FROM docker.io/library/ubuntu:24.04
+
+RUN apt-get update && \
+    apt-get install -y \
+    libmpfr-dev \
+    libgmp-dev \
+    libmpc-dev \
+    ninja-build \
+    sudo \
+    sccache \
+    wget \
+    lsb-release \
+    software-properties-common \
+    gnupg \
+    linux-libc-dev && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN wget https://apt.llvm.org/llvm.sh && \
+    chmod +x llvm.sh && \
+    sudo ./llvm.sh 21 && \
+    rm llvm.sh
+
+RUN ln -sf /usr/include/$(uname -p)-linux-gnu/asm /usr/include/asm