ci.yml

name: CI

on:
  push:
    branches: [main]
  pull_request:

# A new push to a PR supersedes the run already in flight for it. Pushes to
# main are never cancelled, so every commit there keeps its own CI result.
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: ${{ github.event_name == 'pull_request' }}

jobs:
  check:
    name: Format and elaboration
    runs-on: ubuntu-latest
    timeout-minutes: 30
    defaults:
      run:
        # The mill build lives in scala/, not at the repo root.
        working-directory: scala

    steps:
      - uses: actions/checkout@v7
        with:
          # scala/testchipip is vendored as a submodule and is a build dependency.
          submodules: recursive

      - uses: actions/setup-java@v5
        with:
          distribution: temurin
          java-version: '17'

      - name: Cache mill and coursier downloads
        uses: actions/cache@v6
        with:
          path: |
            ~/.cache/mill
            ~/.cache/coursier
          key: mill-${{ runner.os }}-${{ hashFiles('scala/build.mill', 'scala/mill') }}
          restore-keys: mill-${{ runner.os }}-

      # The vendored scala/testchipip submodule is excluded via
      # project.excludePaths in scala/.scalafmt.conf, so this only covers this
      # repo's own sources.
      - name: Check formatting
        run: |
          ./mill mill.scalalib.scalafmt/checkFormatAll

      # Type-checks everything, including the ChiselSim suites. Those are not
      # run here: each `simulate` call builds its own Verilator model, which is
      # far too slow for per-PR CI. Run them locally with `./mill test`.
      - name: Compile
        id: compile
        if: ${{ !cancelled() }}
        run: |
          ./mill test.compile

      # Elaboration-only suites: these run firtool but never start a simulator.
      - name: Elaborate RTL and check register codegen
        if: ${{ !cancelled() && steps.compile.outcome == 'success' }}
        run: |
          ./mill test.testOnly \
            edu.berkeley.cs.uciedigital.phy.PhySpec \
            edu.berkeley.cs.uciedigital.phytest.PhyTestSpec \
            edu.berkeley.cs.uciedigital.tilelink.CodegenSpec

      # Every other test in TileLinkSpec drives a simulator, so select the one
      # generator test by name rather than running the suite.
      - name: Elaborate UcieTL
        if: ${{ !cancelled() && steps.compile.outcome == 'success' }}
        run: |
          ./mill test.testOnly edu.berkeley.cs.uciedigital.tilelink.TileLinkSpec \
            -- -z "generate valid SystemVerilog"