Add CI workflow, Dependabot, and pin GoogleTest SHA

- CI workflow: 3-job matrix (Linux GCC, Linux Clang, macOS AppleClang)
  with system LLVM 19, Z3, clang-format and clang-tidy checks
- Dependabot: weekly grouped updates for GitHub Actions
- Pin GoogleTest GIT_TAG to commit SHA for v1.16.0
- Actions pinned to full SHAs (checkout v6.0.2, cache v5.0.1)
- Fix AuxVarEliminator.cpp: rename compact_signature_soft and
  compact_signature_hw to PascalCase to match project conventions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kyle-elliott-tob

.clang-tidy

@@ -22,6 +22,7 @@ Checks: "*,\
   -readability-identifier-length, \
   -readability-function-cognitive-complexity, \
   -bugprone-easily-swappable-parameters "
+HeaderFilterRegex: 'cobra/'
 WarningsAsErrors: ''
 CheckOptions:
   - key: 'bugprone-argument-comment.StrictMode'

.github/dependabot.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    groups:
+      actions:
+        patterns:
+          - "*"
+    open-pull-requests-limit: 5

.github/workflows/ci.yml

@@ -0,0 +1,109 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-24.04
+            cc: gcc-14
+            cxx: g++-14
+            name: Linux GCC
+            lint: false
+          - os: ubuntu-24.04
+            cc: clang-19
+            cxx: clang++-19
+            name: Linux Clang
+            lint: true
+          - os: macos-14
+            cc: clang
+            cxx: clang++
+            name: macOS
+            lint: false
+
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Install dependencies (Linux)
+        if: runner.os == 'Linux'
+        run: |
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key \
+            | sudo apt-key add -
+          echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-19 main" \
+            | sudo tee /etc/apt/sources.list.d/llvm.list
+          sudo apt-get update -qq
+          sudo apt-get install -y -qq \
+            llvm-19-dev clang-19 clang-format-19 clang-tidy-19 \
+            libz3-dev
+          echo "LLVM_DIR=/usr/lib/llvm-19/lib/cmake/llvm" >> "$GITHUB_ENV"
+
+      - name: Install dependencies (macOS)
+        if: runner.os == 'macOS'
+        run: |
+          brew install llvm@19 z3
+          LLVM_PREFIX="$(brew --prefix llvm@19)"
+          echo "${LLVM_PREFIX}/bin" >> "$GITHUB_PATH"
+          {
+            echo "LLVM_DIR=${LLVM_PREFIX}/lib/cmake/llvm"
+            echo "CC=${LLVM_PREFIX}/bin/clang"
+            echo "CXX=${LLVM_PREFIX}/bin/clang++"
+            echo "LDFLAGS=-L${LLVM_PREFIX}/lib/c++ -Wl,-rpath,${LLVM_PREFIX}/lib/c++"
+          } >> "$GITHUB_ENV"
+
+      - name: Cache GoogleTest
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        with:
+          path: build-deps/install
+          key: gtest-${{ matrix.os }}-${{ matrix.cc }}-v1.16.0
+
+      - name: Build dependencies
+        run: |
+          cmake -S dependencies -B build-deps \
+            -DCMAKE_C_COMPILER="${CC:-${{ matrix.cc }}}" \
+            -DCMAKE_CXX_COMPILER="${CXX:-${{ matrix.cxx }}}" \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DUSE_EXTERNAL_LLVM=ON
+          cmake --build build-deps
+
+      - name: Build CoBRA
+        run: |
+          cmake -S . -B build \
+            -DCMAKE_C_COMPILER="${CC:-${{ matrix.cc }}}" \
+            -DCMAKE_CXX_COMPILER="${CXX:-${{ matrix.cxx }}}" \
+            -DCMAKE_PREFIX_PATH="$(pwd)/build-deps/install" \
+            -DCMAKE_BUILD_TYPE=Release
+          cmake --build build
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+      - name: clang-format check
+        if: matrix.lint
+        run: |
+          find include lib tools \( -name '*.h' -o -name '*.cpp' \) -print0 \
+            | xargs -0 clang-format-19 --dry-run --Werror
+
+      - name: clang-tidy
+        if: matrix.lint
+        run: |
+          find lib tools -name '*.cpp' -print0 \
+            | xargs -0 clang-tidy-19 -p build --warnings-as-errors='*'

dependencies/googletest.cmake

@@ -19,7 +19,7 @@ else()
     message(STATUS "Building GoogleTest from source (v1.16.0)")
     cobra_add_dependency(googletest
         GIT_REPOSITORY https://github.com/google/googletest.git
-        GIT_TAG v1.16.0
+        GIT_TAG 6910c9d9165801d8827d628cb72eb7ea9dd538c5 # v1.16.0
         GIT_SHALLOW ON
         GIT_PROGRESS ON
         CMAKE_ARGS

lib/core/AuxVarEliminator.cpp

@@ -85,7 +85,7 @@ namespace cobra {
             return supported;
         }
 
-        __attribute__((target("bmi2"))) std::vector< uint64_t > compact_signature_hw(
+        __attribute__((target("bmi2"))) std::vector< uint64_t > CompactSignatureHw(
             const std::vector< uint64_t > &sig, uint64_t live_mask, uint32_t num_vars
         ) {
             uint32_t new_count = static_cast< uint32_t >(std::popcount(live_mask));
@@ -122,9 +122,9 @@ namespace cobra {
         std::vector< uint64_t > reduced;
 #if COBRA_X86
         if (has_bmi2()) {
-            reduced = compact_signature_hw(sig, live_mask, num_vars);
+            reduced = CompactSignatureHw(sig, live_mask, num_vars);
         } else {
-            reduced = compact_signature_soft(sig, live_mask, num_vars);
+            reduced = CompactSignatureSoft(sig, live_mask, num_vars);
         }
 #else
         reduced = CompactSignatureSoft(sig, live_mask, num_vars);

lib/core/ProductIdentityRecoverer.cpp

@@ -39,7 +39,7 @@ namespace cobra {
             const size_t sig_len = 1ULL << num_vars;
 
             // Compute boolean signatures for all 4 factors
-            const const Expr *factors[4] = {
+            const Expr *factors[4] = {
                 add_node.children[0]->children[0].get(),
                 add_node.children[0]->children[1].get(),
                 add_node.children[1]->children[0].get(),