Support Multi-Arch Docker Builds (The-OpenROAD-Project#1075)

Tested on Apple M1 and AWS Graviton.

+ Add support for multiple-architecture building
    + Support for amd64, ppc64le and arm64v8 added
    + amd64 and arm64v8 will be automatically built by the CI

~ Major CI Overhauls
   ~ Added composite actions for the Docker build and setting environment variables
   ~ pdk build is now its own job, and amd64/aarch64 have a job each
   ~ matrix -> design_matrix, designs only tested on amd64 for performance reasons

~ run/build base docker images now pushed to Docker Hub based on a hash of dependency lists (to work with the buildx `docker-container` driver)

- Remove pandas (overkill for what we're using it for)

- Remove `cugr`, `drcu` *for now* (they're x86-64 Linux-only utilities)

.github/actions/docker_build/action.yml

@@ -0,0 +1,59 @@
+name: Docker Build
+description: Build an OpenLane Docker Container
+inputs:
+  arch:
+    description: "The Docker architecture/platform to build for"
+    required: true
+    default: "amd64"
+  dockerhub_user:
+    description: The input dockerhub user
+    required: false
+    default: ""
+  dockerhub_password:
+    description: The input dockerhub password
+    required: false
+    default: ""
+runs:
+  using: "composite"
+  steps:
+    - uses: actions/checkout@v2
+    - uses: docker/setup-buildx-action@v2
+    - uses: ./.github/actions/set_env_variables
+
+    - name: Check If Going To Push An Image To Docker
+      shell: bash
+      run: |
+        export PUSHING=$(ruby -e 'if ("${{ github.event_name }}" != "pull_request" && "${{ inputs.dockerhub_user }}" != ""); print(1) else print(0) end')
+        echo "PUSHING=$PUSHING" >> $GITHUB_ENV
+
+    - name: Login to DockerHub
+      if: ${{ env.PUSHING == '1' }}
+      uses: docker/login-action@v1
+      with:
+        username: ${{ inputs.dockerhub_user }}
+        password: ${{ inputs.dockerhub_password }}
+
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v1
+
+    - name: Docker Build
+      shell: bash
+      run: |
+        export BUILD_IF_CANT_PULL=1
+        export BUILD_COMMAND="docker build"
+        if [ "$PUSHING" = "1" ]; then
+          export BUILD_IF_CANT_PULL_THEN_PUSH=1
+          export BUILD_COMMAND="docker buildx build --load --cache-from=type=gha --cache-to=type=gha,scope=${{ github.workflow }}}"
+        fi
+        export BUILD_ARCH=${{ inputs.arch }}
+        cd docker/ && make merge
+
+    - name: Export Docker Image
+      shell: bash
+      run: docker save -o /tmp/image-${{ inputs.arch }}.tar ${{ env.OPENLANE_IMAGE_NAME }}-${{ inputs.arch }}
+
+    - name: Upload Docker Image
+      uses: actions/upload-artifact@v2
+      with:
+        name: docker-image-${{ inputs.arch }}
+        path: /tmp/image-${{ inputs.arch }}.tar

.github/actions/set_env_variables/action.yml

@@ -0,0 +1,20 @@
+name: Set up environment variables
+description: Sets up various environment variables required by various OpenLane steps.
+runs:
+  using: "composite"
+  steps:
+    - name: Export Repo URL
+      shell: bash
+      run: echo "REPO_URL=https://github.com/${{ github.repository }}.git" >> $GITHUB_ENV
+
+    - name: Export PDK ROOT
+      shell: bash
+      run: echo "PDK_ROOT=/usr/local/pdk" >> $GITHUB_ENV
+
+    - name: Export Branch Name
+      shell: bash
+      run: echo "BRANCH_NAME=${GITHUB_REF##*/}" >> $GITHUB_ENV
+
+    - name: Export Temp Image Name
+      shell: bash
+      run: echo "OPENLANE_IMAGE_NAME=openlane:intermediate" >> $GITHUB_ENV

.github/scripts/run_tests.py

@@ -22,7 +22,7 @@
 import subprocess
 from gh import gh
 
-threads_used = int(subprocess.check_output(["nproc"]).decode("utf-8")) - 1
+threads_used = os.cpu_count() - 1
 test_name = "ci_test"
 design = sys.argv[1]
 print(f"Running on designs {test_name} using {threads_used} threads…")

.github/workflows/lint.yml

@@ -1,11 +1,10 @@
 name: Lint
 on:
-  # Runs on pushes to all but CID-latest-branches
-  # CID-latest branches automatically create PRs, let's just let the tests run on those
+  # Runs on all pushes to branches
   push:
-  # Runs on Pull Requests
+  # Runs on all PRs
   pull_request:
-  # Runs manually
+  # Manual Dispatch
   workflow_dispatch:
 
 jobs: