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Hydrogen

Self-hosted compiler architecture

This is contributor documentation. Release users install hydrogen-stage1 and do not need the historical C++ bootstrap to use Hydrogen.

The Hydrogen-written compiler emits standalone Linux x86-64 ELF executables by default. It binds the complete source/reference closure of its CLI project and can compile itself. It can additionally produce a constrained PE32+ UEFI console application.

UEFI proof target

Section titled “UEFI proof target”

The uefi-x64 path is implemented in Hydrogen. It writes a minimal PE32+ EFI image, provides an x86-64 EFI entry stub, encodes console text as UTF-16, and calls the firmware text-output function through the UEFI system table. mtools and xorriso package that executable into boot media; they do not compile it.

This is intentionally not a general ABI/runtime layer. It currently lowers the console proof profile—ASCII literals passed to System.Console.WriteLine from the static entry point. Managed heap support, firmware wrappers, keyboard support, graphics, and general foreign-function calls are future work.

Rebuild from a seed

Section titled “Rebuild from a seed”

Keep a verified compiler outside a new output directory, then rebuild the compiler project with it:

Terminal window
"$HYDROGEN" build samples/self_hosting/Hydrogen.Compiler.Cli/Hydrogen.Compiler.Cli.hyproj \
  -o hydrogen-rebuilt
chmod +x hydrogen-rebuilt

A clean source-only checkout still needs a trusted initial seed. Repeated bootstrap proofs build successive generations and verify their behavior and representative artifacts.