bazel: build OpenROAD and run ORFS flows

Signed-off-by: Øyvind Harboe <[email protected]>

Author: oharboe

.github/workflows/github-actions-bazel-build.yml

@@ -0,0 +1,47 @@
+name: bazel-build
+
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+
+jobs:
+  Build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Create Cache Timestamp
+        id: cache_timestamp
+        uses: nanzm/[email protected]
+        with:
+          format: 'YYYY-MM-DD-HH-mm-ss'
+
+      - name: Mount bazel cache
+        uses: actions/cache@v4
+        with:
+          path: "~/.cache/bazel"
+          key: bazelcache_${{ steps.cache_timestamp.outputs.time }}
+          restore-keys: bazelcache_
+
+      - name: Build
+        run: |
+          # FIXME once OpenROAD is converted fully to bzlmod, we can remove this
+          (cd tools/OpenROAD && bazelisk build :openroad -c opt)
+          cd flow
+          bazelisk build ...
+
+      - name: Trim Bazel Cache
+        run: |
+          echo "Trim download cache"
+          du -sh $(bazelisk info repository_cache)
+          rm -r $(bazelisk info repository_cache)
+
+          echo "Other remaining things that are big"
+          du -h -t 200M ~/.cache/bazel/*/ | sort -hr