# BOOTSTRAP

How `ww` builds itself.

`ww` is self-hosted: the ww-side compiler/assembler/linker/driver live
under `selfhost/cmd/` and reach a byte-identical fixed point under
`make bootstrap`. But the *first* ww binary on a fresh checkout has to
come from somewhere. Today, that "somewhere" is a small C bootstrap
toolchain — the **Cstage**:

    cmd/wcc/   frontend library (lex, parse, check)  → libwcc.a
    cmd/w6c/    amd64 compiler   .ww → .s
    cmd/w6a/    amd64 assembler  .s  → .o
    cmd/w6l/    amd64 linker     .o  → static ELF
    cmd/ww/    user-facing driver (orchestrates w6c → w6a → w6l)

Cstage is built with `cc`. Once it exists, it compiles the
ww-rewritten tools (the **wwstage**) under `selfhost/cmd/`, which then
self-compile to a byte-identical fixed point. After that, no C is
involved.

## Build flow

    cstage     (cc → C tools, one-time)
      │
      ├──→ ww1   wwstage tools, built by Cstage
      │     │
      │     └──→ ww2   wwstage self-compiles
      │            │
      │            └──→ ww3   ww2 self-compiles
      │                   │
      │                   ↓
      │              cmp ww2 ww3   →   fixed point ✓
      ↑
      └ from here on, no C is invoked

## Make targets

    make                builds cstage + wwstage + libs
    make cstage         Cstage only (cc → ww, w6c, w6a, w6l, wwdump, libs)
    make wwstage        wwstage only (assumes cstage)
    make bootstrap      three-stage build; gates on cmp ww2 == ww3
    make test           runs all tests, including 990–995 (ww-side
                        tools vs C-side tools, byte-for-byte, plus
                        the wwstage rebuilding itself in 995)

Without cc:

    make bootstrap-snapshot   populate bootstrap/$(ARCH)/ from the
                              currently-built wwstage (gitignored
                              by default)
    make nocc                 cold-start from bootstrap/$(ARCH)/,
                              rebuild the wwstage from source, gate
                              on `stage-0 == rebuilt` byte-for-byte.
                              cc is never invoked.

## Status

Phase 10 of `PLAN.md` is at its first exit criterion: the bootstrap is
green and `selfhost/cmd/{wcc,w6c,w6a,w6l,ww}` are byte-identical to their
Cstage counterparts. Test 995 pins the stronger property — the
wwstage rebuilds every one of its own tools through `ww_ww + w6c_ww +
w6a_ww + w6l_ww`, byte-for-byte. Test 996 pins the equivalent for the
dynamic linker: `w6l_ww` with `-L`/`-l` produces a byte-identical
PT_INTERP+PT_DYNAMIC binary to C-side `w6l` on snake.

`make nocc` is wired and verifies stage-0 self-reproduction locally;
the stage-0 binaries under `bootstrap/$(ARCH)/` are gitignored until
ready to commit. The second exit criterion — deleting the C trees —
is **still deferred to v1.0**: shipping the stage-0 binaries is a
one-way door (they become the project's new trust surface), and the
compiler is still churning. A `git clone` today still requires `cc`
unless the local working copy has already done `make
bootstrap-snapshot` once.

## What "no C" looks like

The pieces are already wired; only the binary commit is held back.
When the compiler stabilises:

1. On each supported arch, run `make wwstage && make bootstrap-snapshot`
   to populate `bootstrap/<arch>/{ww,w6c,w6a,w6l}` from the current
   wwstage. Verify with `make nocc`.
2. `git add -f bootstrap/<arch>/{ww,w6c,w6a,w6l}` — explicit because
   the dir is gitignored. The binary SHAs become the new trust
   surface.
3. Delete `cmd/wcc/`, `cmd/w6c/`, `cmd/w6a/`, `cmd/w6l/`, `cmd/ww/`.
   Drop `CC`/`AR` C-tool dependencies from the top-level Makefile.
4. Move `selfhost/cmd/*` to `cmd/*` and `make nocc` becomes the
   default `make`.
5. Build path: stage-0 binary → ww1 → ww2 → fixed point, same as
   today, just without `cc`.

This is the standard self-hosting story (Go, Rust, OCaml all do
variants of it). The bootstrap binaries become the new "trusting
trust" surface.