chore: run mac builds on master

.github/ensure-builder/action.yml

@@ -31,6 +31,14 @@ runs:
           echo "runner_concurrency=20" >> $GITHUB_OUTPUT
           echo "runner_label=$USERNAME-x86" >> $GITHUB_OUTPUT
           echo "ttl=40" >> $GITHUB_OUTPUT
+        elif [[ $TYPE == builder-mac-x86 ]]; then
+          # 64-core ARM instance type
+          echo "instance_type=mac1.metal" >> $GITHUB_OUTPUT
+          echo "ami_id=?????" >> $GITHUB_OUTPUT
+          echo "ebs_cache_size=256" >> $GITHUB_OUTPUT
+          echo "runner_concurrency=8" >> $GITHUB_OUTPUT
+          echo "runner_label=$USERNAME-arm" >> $GITHUB_OUTPUT
+          echo "ttl=40" >> $GITHUB_OUTPUT
         elif [[ $TYPE == builder-arm ]]; then
           # 64-core ARM instance type
           echo "instance_type=r6g.16xlarge" >> $GITHUB_OUTPUT

.github/workflows/ci-mac.yml

@@ -0,0 +1,120 @@
+name: CI (Mac)
+on:
+  push:
+    branches:
+      - master
+      - '*/*mac-build'
+  workflow_dispatch:
+    inputs: {}
+concurrency:
+  group: ci-master-mac
+env:
+  RUN_ID: ${{ github.run_id }}
+  RUN_ATTEMPT: ${{ github.run_attempt }}
+  USERNAME: master
+  GITHUB_TOKEN: ${{ github.token }}
+  GH_SELF_HOSTED_RUNNER_TOKEN: ${{ secrets.GH_SELF_HOSTED_RUNNER_TOKEN }}
+  AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+  AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+  BUILD_INSTANCE_SSH_KEY: ${{ secrets.BUILD_INSTANCE_SSH_KEY }}
+  GIT_COMMIT: ${{ github.sha }}
+  # kludge until we move away from runners
+  WAIT_FOR_RUNNERS: false
+jobs:
+  setup:
+    uses: ./.github/workflows/setup-runner.yml
+    with:
+      username: ${{ github.event.pull_request.user.login || github.actor }}
+      runner_type: builder-mac-x86
+    secrets: inherit
+
+  changes:
+    runs-on: ubuntu-20.04
+    # Required permissions.
+    permissions:
+      pull-requests: read
+    # Set job outputs to values from filter step
+    outputs:
+      barretenberg: ${{ steps.filter.outputs.barretenberg }}
+    steps:
+      - uses: actions/checkout@v4
+        with: { ref: "${{ env.GIT_COMMIT }}" }
+      - uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36
+        id: filter
+        with:
+          filters: |
+            barretenberg:
+              - 'barretenberg/**'
+
+  build:
+    needs: [changes]
+    if: needs.changes.outputs.barretenberg == 'true'
+    runs-on: ${{ github.event.pull_request.user.login || github.actor }}-arm
+    steps:
+      - uses: actions/checkout@v4
+        with: { ref: "${{ env.GIT_COMMIT }}" }
+      - uses: ./.github/ci-setup-action
+        with:
+          concurrency_key: build-mac
+
+      - name: Install bleeding edge cmake
+        run: |
+          sudo apt -y remove --purge cmake
+          sudo snap install cmake --classic
+
+      - name: Create Build Environment
+        run: |
+          sudo apt-get update
+          sudo apt-get -y install ninja-build
+
+      - name: Install Clang16
+        run: |
+          wget https://github.com/llvm/llvm-project/releases/download/llvmorg-16.0.0/clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz
+          tar -xvf clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz
+          sudo cp clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/* /usr/local/bin/
+          sudo cp -r clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/include/* /usr/local/include/
+          sudo cp -r clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/lib/* /usr/local/lib/
+          sudo cp -r clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/share/* /usr/local/share/
+
+      - name: Compile Barretenberg
+        run: |
+          cd barretenberg/cpp
+
+          cmake --preset default -DCMAKE_CXX_FLAGS="-stdlib=libc++" -DCMAKE_BUILD_TYPE=RelWithAssert -DTARGET_ARCH=westmere
+          cmake --build --preset default --target bb
+
+
+  rerun-check:
+    runs-on: ubuntu-20.04
+    permissions:
+      actions: write
+    needs: [setup, build]
+    if: ${{ !cancelled() }}
+    steps:
+      - name: Check for Rerun
+        env:
+          # We treat any skipped or failing jobs as a failure for the workflow as a whole.
+          HAD_FAILURE: ${{ contains(needs.*.result, 'failure') }}
+          GH_REPO: ${{ github.repository }}
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          if [[ $HAD_FAILURE == true ]] && [[ $RUN_ATTEMPT -lt 2 ]] ; then
+            echo "Retrying first workflow failure. This is a stop-gap until things are more stable."
+            gh workflow run rerun.yml -F run_id=${{ github.run_id }}
+          fi
+
+  # NOTE: we only notify failures after a rerun has occurred
+  notify:
+    needs: [build]
+    runs-on: ubuntu-latest
+    if: ${{ github.ref == 'refs/heads/master' && failure() && github.run_attempt >= 2 }}
+    steps:
+      - name: Send notification to aztec3-ci channel if workflow failed on master
+        uses: slackapi/[email protected]
+        with:
+          payload: |
+            {
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_NOTIFY_WORKFLOW_TRIGGER_URL }}