Dollar-Macro Check

A clang-tidy check that enforces $macros to visually separate them from regular identifiers.

With this check enabled, you will get warnings if you try to define a macro without prefixing its name with a $. Likewise, you will get a warning if you use a regular identifier that starts with $.

Build Requirements

• CMake 3.20+
• Ninja
• Clang/Clang++
• Pre-built LLVM and Clang

Building

Quick Start with Build Script

python build-plugin.py

This configures and builds the plugin, installing it to ./install/lib/dollar_macros.so.

Note: Requires LLVM to be pre-built at ./llvm-project/build/ (or specify with --llvm-build).

Using CMake Directly

# Configure
cmake -B build -S . \
  -DLLVM_SRC_DIR=./llvm-project \
  -DLLVM_BUILD_DIR=./llvm-project/build \
  -DCMAKE_INSTALL_PREFIX=./install

# Build
ninja -C build

# Install
ninja -C build install

Custom Paths

python build-plugin.py \
  --llvm-src /path/to/llvm-project \
  --llvm-build /path/to/llvm-project/build \
  --install-dir ./install

Usage

Configuration

Add the check to your .clang-tidy configuration:

Checks: 'dollar-macro'
CheckOptions:
  - key: dollar-macro.ignore-prefixes
    value: 'SOMELIB_,BOOST_'

Use ignore-prefixes to permit additional (comma-separated) prefixes:

• SOMELIB_ - Allow macros that use the SOMELIB_ prefix
• BOOST_ - Allow macros that use Boost's BOOST_ prefix

Reserved identifiers and system header macros are automatically excluded.

See example/.clang-tidy for a complete configuration example.

Command Line

Run clang-tidy with the plugin:

clang-tidy --load=/path/to/dollar_macros.so -checks='dollar-macro' file.cpp

Testing

The test/ directory contains test cases demonstrating the check's behavior:

lit test/