Release Builds

Release builds produce optimized binaries for production deployment. Phase 5 applies Cargo profile settings tuned during Phase 3 optimization.

Optimization Profiles

Phase 3 writes [profile.release] settings to the output project’s Cargo.toml. Three profiles are available:

Cargo.toml Configuration

[profile.release]
opt-level = 3
lto = "fat"
codegen-units = 1
strip = "symbols"
panic = "abort"

What Each Setting Does

opt-level = 3 – Maximum optimization. Enables auto-vectorization, loop unrolling, and function inlining beyond the default level 2.

lto = "fat" – Link-Time Optimization across all crates. Allows the linker to optimize across crate boundaries, eliminating dead code and enabling cross-crate inlining. Increases build time significantly.

codegen-units = 1 – Forces single-threaded code generation. This allows LLVM to see the entire crate at once, enabling better optimization at the cost of slower compilation.

strip = "symbols" – Removes debug symbols from the final binary, reducing size by 50-80%.

panic = "abort" – Generates abort on panic instead of unwinding. Reduces binary size and improves performance by eliminating unwind tables.

Profile-Guided Optimization (PGO)

For maximum performance, PGO uses a profiling run to guide optimization:

# Step 1: Build with instrumentation
RUSTFLAGS="-Cprofile-generate=/tmp/pgo-data" \
    cargo build --release

# Step 2: Run representative workload
./target/release/app < benchmark-input.txt

# Step 3: Rebuild with profile data
RUSTFLAGS="-Cprofile-use=/tmp/pgo-data/merged.profdata" \
    cargo build --release

PGO typically provides an additional 5-15% speedup over standard release builds by optimizing branch prediction and code layout.

Size Optimization

For deployment-constrained environments (embedded, WASM):

[profile.release]
opt-level = "z"      # Optimize for size
lto = true
codegen-units = 1
strip = true
panic = "abort"

CLI Usage

# Standard release build
batuta build --release

# With aggressive optimization
batuta build --release --profile aggressive

# Check binary size
ls -lh rust-output/target/release/app

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