Add CI action that reports clang-tidy warnings as review comments.

 #xls-build-gardener

.github/workflows/review-actions.yml

@@ -0,0 +1,59 @@
+name: Auto Review Analyzers
+
+on:
+  push:
+    branches:
+      - main
+    paths-ignore:
+      # Do not trigger action when docs are updated.
+      - 'docs/**'
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  clang-tidy:
+    runs-on:
+      labels: ubuntu-22.04-64core
+
+    permissions:
+      # Open PR comments
+      pull-requests: write
+      # OPTIONAL: auto-closing conversations requires the `contents` permission
+      contents: write
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+        fetch-depth: 0
+
+    - name: Fetch base branch to compare to
+      run: |
+        git remote add review-base "https://github.com/${{ github.event.pull_request.base.repo.full_name }}"
+        git fetch --no-tags --no-recurse-submodules review-base "${{ github.event.pull_request.base.ref }}"
+
+    - name: Restore Nightly Bazel Cache
+      uses: actions/cache/restore@v4
+      with:
+        path: "~/.cache/bazel"
+        key: bazel-cache-nightly-${{ runner.os }}-${{ github.sha }}
+        restore-keys: bazel-cache-nightly-${{ runner.os }}-
+
+    - name: Create compilation DB
+      run: |
+        xls/dev_tools/make-compilation-db.sh
+
+    - name: Run clang-tidy on diff
+      run: |
+        mkdir clang-tidy-result
+        git diff -U1000 "$(git merge-base HEAD review-base/${{ github.event.pull_request.base.ref }})" | xls/dev_tools/run-clang-tidy-diff.sh -p1 -path build -export-fixes clang-tidy-result/fixes.yml
+
+    - name: Run clang-tidy-pr-comments action
+      uses: hzeller/clang-tidy-pr-comments@master
+      with:
+        # Token to allow commenting
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        clang_tidy_fixes: clang-tidy-result/fixes.yml
+        request_changes: true
+        suggestions_per_comment: 10

xls/dev_tools/make-compilation-db.sh

@@ -19,7 +19,7 @@ set -e
 readonly OUTPUT_BASE="$(bazel info output_base)"
 
 readonly COMPDB_SCRIPT="${OUTPUT_BASE}/external/com_grail_bazel_compdb/generate.py"
-[ -r "${COMPDB_SCRIPT}" ] || bazel fetch @com_grail_bazel_compdb//...
+[ -r "${COMPDB_SCRIPT}" ] || bazel fetch --noshow_progress @com_grail_bazel_compdb//...
 
 python3 "${COMPDB_SCRIPT}"
 
@@ -33,4 +33,3 @@ s/ -f[^ ]*/ /g             # remove all -fxyz options
 s/ --target[^ ]*/ /g       # target platform not needed, might confuse
 s/ -stdlib=libc++/ /       # otherwise, clang-tidy does not find c++ headers
 EOF
-

xls/dev_tools/run-clang-tidy-diff.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Copyright 2023 The XLS Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Prepare compilation DB and run clang-tidy-diff that we already have
+# bundled in our toolchain.
+# Reads a unified diff from stdin. If a header is removed, we want to get
+# enough context to see that it is not used anywhere; so invoke like
+#
+# git diff -U1000 | xls/dev_tools/run-clang-tidy-cached.sh -p1
+
+CLANG_TIDY_LLVM_BASE="$(bazel info output_base)/external/llvm_toolchain_llvm/"
+
+"${CLANG_TIDY_LLVM_BASE}/share/clang/clang-tidy-diff.py" \
+  -clang-tidy-binary="${CLANG_TIDY_LLVM_BASE}/bin/clang-tidy" "$@"

xls/dslx/errors.cc

@@ -14,8 +14,8 @@
 
 #include "xls/dslx/errors.h"
 
-#include <string>
-#include <string_view>
+//#include <string>   testing
+//#include <string_view>
 
 #include "absl/status/status.h"
 #include "absl/strings/str_cat.h"

xls/ir/function_builder.cc

@@ -19,7 +19,7 @@
 #include <memory>
 #include <optional>
 #include <ostream>
-#include <string>
+// #include <string>  // testing clang tidy
 #include <string_view>
 #include <utility>
 #include <variant>