Add a nightly ASAN build.

.github/workflows/asan.yaml

@@ -0,0 +1,80 @@
+name: CI - Address Sanitizer (nightly)
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+on:
+  schedule:
+    - cron: "0 12 * * *" # Daily at 12:00 UTC
+  workflow_dispatch: # allows triggering the workflow run manually
+  pull_request:  # Automatically trigger on pull requests affecting this file
+    branches:
+      - main
+    paths:
+      - '**workflows/asan.yml'
+
+jobs:
+  upstream-dev:
+    runs-on: ubuntu-20.04-16core
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.12"]
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938  # v4.2.0
+        with:
+          path: jax
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938  # v4.2.0
+        with:
+          repository: python/cpython
+          path: cpython
+          ref: v3.12.6
+      - name: Install clang 18
+        run: |
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo deb http://apt.llvm.org/focal/ llvm-toolchain-focal-18 main | sudo tee -a /etc/apt/sources.list
+          sudo apt update
+          sudo apt install clang-18 libstdc++-10-dev
+      - name: Build CPython with ASAN enabled
+        env:
+          ASAN_OPTIONS: detect_leaks=0
+        run: |
+          cd cpython
+          mkdir ${GITHUB_WORKSPACE}/cpythonasan
+          CC=clang-18 ./configure --prefix ${GITHUB_WORKSPACE}/cpythonasan --with-address-sanitizer --without-pymalloc
+          make -j16
+          make install
+          ${GITHUB_WORKSPACE}/cpythonasan/bin/python3 -m venv ${GITHUB_WORKSPACE}/venv
+      - name: Install JAX test requirements
+        env:
+          ASAN_OPTIONS: detect_leaks=0
+        run: |
+          source ${GITHUB_WORKSPACE}/venv/bin/activate
+          cd jax
+          pip install -r build/test-requirements.txt
+      - name: Build and install JAX
+        env:
+          ASAN_OPTIONS: detect_leaks=0
+        run: |
+          source ${GITHUB_WORKSPACE}/venv/bin/activate
+          cd jax
+          python build/build.py --bazel_options=--copt=-fsanitize=address --clang_path=/usr/bin/clang-18
+          pip install dist/jaxlib-*.whl
+          pip install -e .
+      - name: Run tests
+        env:
+          ASAN_OPTIONS: detect_leaks=0
+          JAX_NUM_GENERATED_CASES: 1
+          JAX_ENABLE_X64: true
+          JAX_SKIP_SLOW_TESTS: true
+          PY_COLORS: 1
+        run: |
+          source ${GITHUB_WORKSPACE}/venv/bin/activate
+          cd jax
+          echo "JAX_NUM_GENERATED_CASES=$JAX_NUM_GENERATED_CASES"
+          echo "JAX_ENABLE_X64=$JAX_ENABLE_X64"
+          echo "JAX_SKIP_SLOW_TESTS=$JAX_SKIP_SLOW_TESTS"
+          # The LD_PRELOAD works around https://github.com/google/sanitizers/issues/934#issuecomment-649516500
+          LD_PRELOAD=/lib/x86_64-linux-gnu/libstdc++.so.6 python -m pytest -n auto --tb=short --maxfail=20 tests
+