Repository Guidelines — tofino

Purpose

The Tofino backend targets the Tofino 1/2 chip family. It transforms frontend P4 IR into a Tofino-specific pipeline IR and performs resource allocation for the target architecture.

Key Entry Points

• backends/tofino/bf-p4c/README.md: design overview, dependencies, and terminology.
• backends/tofino/CMakeLists.txt: build targets and options.
• backends/tofino/bf-p4c/: main compiler logic.
• backends/tofino/bf-p4c/parde/, mau/, phv/: parser/deparser, match-action, and PHV allocation subsystems.

Architecture Notes

• Mid-end transforms frontend IR into a Tofino pipeline IR rooted at IR::BFN::Pipe.
• Backend focuses on resource allocation and architecture-specific scheduling across parser/deparser and MAU stages.

Dependencies (Tests)

• Tests rely on the Tofino assembler and model; see backends/tofino/bf-p4c/README.md for setup and required versions.

Tests & Outputs

• Test targets are backend-specific; see backends/tofino/ CMake files and bf-p4c/ CMake/CMakelists for custom targets.
• Idiomatic filtered runs: ctest --test-dir build -j<N> --output-on-failure -R tofino.
• Integration inputs and expected outputs live under testdata/.

Navigation Tips

• Start in bf-p4c/ and follow the pipeline IR (IR::BFN::*) and subsystem directories (parde/, mau/, phv/).