sem

Performance

5 optimizations that make sem significantly faster:

• xxHash64 replaces SHA-256 for content and structural hashing (~10x faster)
• Zero-allocation streaming structural hash hashes AST tokens directly from source bytes
• Cached tree resolution resolves git trees once per scope instead of per file (31% faster on ranges)
• LTO + codegen-units=1 for better cross-crate inlining
• HashSet<&str> eliminates String allocations in entity matching

Benchmarks (hyperfine -N, 50 runs)

| Scenario | v0.2.0 | v0.3.0 | Change |
|---|---|---|---|
| Small (1 file) | 7ms | 5ms | 29% faster |
| Medium (5 files) | 10ms | 8ms | 20% faster |
| Large (13 files) | 22ms | 19ms | 14% faster |
| Range (8 commits) | 35ms | 24ms | 31% faster |

sem diff is now faster than git diff on medium commits (8ms vs 9ms) while providing full entity-level semantic analysis.

New since v0.2.0

• PHP support (13 languages total)
• Fortran support
• C++, Ruby, C# support
• Java and C support
• sem blame for entity-level blame
• sem graph for cross-file dependency graph
• sem impact for transitive impact analysis
• Parallel entity extraction via rayon
• Cosmetic vs structural change detection via AST-normalized structural hashing
• Incremental graph updates
• llms.txt for AI agent consumption