Demo of the precompiler for C/C++, which is essentially a high-performance C/C++ file splitter that breaks large source files into smaller compilation units based on function and variable dependencies. Both GCC and Clang C/C++ compilers are supported.
cargo run
The usage information is displayed as follows:
cargo run -- --help
Testing on SQLite's 9.6MB amalgamation file (~260K LOC) with 48-core parallel compilation:
| Metric | Original | Split | Improvement |
|---|---|---|---|
| Compilation time | ~35s | ~6s | 5.8x faster |
| PUs generated | 1 | 2503 | - |
| Code size (text) | 970.0K | 970.5K | 0.05% diff |
Why splitting helps: A single large file cannot be parallelized. Splitting into 2503 PUs enables full utilization of all CPU cores.
- Split mode is designed for single large amalgamation files (like SQLite) where the file cannot otherwise be parallelized
- Passthrough mode is appropriate for multi-file projects - files below the threshold (default: 1MB) pass through without splitting
- Code size is virtually identical between original and split binaries (verified with stripped executables)
- For incremental builds, split mode enables finer granularity - changing one function only requires recompiling a ~35KB PU vs an entire source file
| Test Suite | Result |
|---|---|
| SQLite amalgamation | 2503/2503 (100%) |
| Vim source files (125 files) | 8304/8304 (100%) |