Three coupled changes that unblock the ecdsa quantum-circuit
simulator's run on the C tier from neoblanka.
1. c/Makefile autodetects libgc-dev — if /usr/include/gc.h is
present, the build links Boehm and defines USE_BOEHM_GC. Without
GC, ul_free is a no-op (lumbda.h:35) and every allocation leaks;
small REPL snippets work but workloads with thousands of envs
OOM the process. Override with USE_GC=0 to force the malloc-only
path for diagnostics.
2. c/main.c calls GC_INIT before init_symbols, then GC_disable.
GC_INIT registers the stack base for conservative scan — without
it some Linux configs miss roots. GC_disable is a deliberate
stopgap: lumbda Values are NaN-boxed pointers that conservative
Boehm cannot recognize as pointers, so live targets get reclaimed
(env binding symbol payloads, SymbolEntry strings) and lookups
fail with "undefined: <sym>". Reproducing this without GC_disable
on the GC build: any sim.lsp call chain triggers the corruption
after ~100 named-let iterations. Until tracing is precise,
growing the heap is safer than wrong results. Long-running
workloads run under ulimit -v.
3. c/builtins.c gains rename-file and delete-file matching the
Python tier (lumbda.py:3468). sim.lsp's write-portal! pattern
(write to .tmp, rename) needs rename-file to land cross-tier
identical results.
4. tests/regression-named-let-leak.lsp + .sh pin four shapes that
blew up ecdsa: the c/TODO-named-let-bytecode.md repro, the F1
shape from foxhop.net's lumbda-c-tier-leak-SP.md (12-line
minimum), a 200-iter scaled variant, and a sim.lsp run-ops!
mirror. Wired into root Makefile as regression-named-let-leak;
added to test-all. Wrapper caps memory at 256 MB virt and 15s
per tier so a leak regression fails the run instead of consuming
host RAM.
Known limits:
- --fast JIT still has the named-let + inner user-fn call hang
(separate TODO; tree-walker handles this fine).
- GC_disable means the heap grows; workloads must bound their work
budget. ecdsa's sim runs comfortably in 5 MB.
Verified inside a 2G/2vCPU QEMU guest (foxhop.net ecdsa/vm-runner.sh):
- test-c (tree-walker) — 35/35 PASS
- bench-c (tree-walker) — score 18 matches Python tier byte-identical
- F1 probe (tree-walker) — all four steps PASS
Historical internal name "uncommonlisp" retired in favor of the
public name "lumbda" ahead of lumbda.com going live. Scope of
this commit:
Source files renamed:
uncommonlisp.py -> lumbda.py
asm/uncommonlisp.s -> asm/lumbda.s
c/uncommonlisp.h -> c/lumbda.h
whitepaper/uncommonlisp-whitepaper -> whitepaper/lumbda-whitepaper (.rst + .pdf)
Binaries renamed (tracked ones; c/ was always gitignored):
asm/uncommonlisp, asm/uncommonlisp-gc, asm/uncommonlisp.o,
asm/uncommonlisp-gc.o -> asm/lumbda(-gc)(.o)
c/.gitignore -> ignores lumbda
Internal string updates (sed pass ordered longest-first):
asm/uncommonlisp -> asm/lumbda
c/uncommonlisp -> c/lumbda
uncommonlisp.py -> lumbda.py
UNCOMMONLISP_BIN -> LUMBDA_BIN (asm/test.sh env var)
"uncommonlisp> " -> "lumbda> " (asm REPL prompt baked into binary)
UNCOMMONLISP -> LUMBDA (macros, comments)
uncommonlisp -> lumbda (prose)
Binary portal magic updated:
"ULPORTAL" -> "LUMBDAB1" # "Lumbda Binary v1"
Old portal files are not backward-compatible — this is a deliberate
break since it's the rename moment. S-expression portals already
carry their own ";; lumbda-portal v1" header and remain cleanly
versioned.
WHITEPAPER.pdf / WHITEPAPER.rst symlinks repointed to the renamed
files. Makefile's whitepaper target targets lumbda-whitepaper.pdf.
Not changed (intentional, separate phases):
- Filesystem directory /home/fox/git/uncommonlisp itself
(fox renames locally and the gitlab repo URL in a follow-up)
- tests.py hardcoded cwd=/home/fox/git/uncommonlisp
(matches the current on-disk location; will flip when the
directory rename ships)
- Git history (immutable; old commits still say uncommonlisp,
which is correct — that's what they were)
Verified:
137 asm no-GC + 137 asm GC + 571 Python + 83 C + 189 shared
functional tests all pass under the new names.
bench-gc-http (2000 req): all 4 cells behave as expected
(cells 1/2 flat, 3 leaks, 4 bounded at 1 chunk).
Python REPL, C REPL, asm REPL all start cleanly.
Full continuations: FullCont captures frames/stack/env with deep copy.
VM trampoline via setjmp/longjmp. Multi-shot safe via deep_copy_env.
Portal (new c/portal.c): serialize env + continuation to JSON,
resume on another machine. portal-checkpoint! triggers mid-VM save.
83/83 C unit tests + 181/181 functional tests pass.
Real native machine code via mmap(PROT_EXEC). No exec(). No strings.
Raw x86_64 bytes: mov, add, sub, imul, cmp, je, jne, call, ret, jmp.
ack(3,4): 0.12ms JIT vs 1.5ms CPython vs 28ms interpreter
fib-rec(20): 0.16ms JIT vs 3.4ms CPython vs 40ms interpreter
Added cond support to JIT (cascaded comparisons → conditional jumps).
Fixed JIT cache: sentinel value prevents retry on unjittable functions.
System V AMD64 ABI: args in rdi/rsi/rdx, callee-saved r12-r15.
Tail calls use jmp (true TCO at machine code level).
691 lines of jit.c. 114 functional tests pass. All C tests pass.
Complete C port of the Scheme interpreter. Same .lsp files run in
both Python and C with identical output.
Architecture:
- NaN-boxed 64-bit values (zero-alloc numbers)
- Hash-map environments with parent chain + global shortcut
- Interned symbols
- TCO via explicit loop (eval) and TAIL_CALL/SELF_TAIL_CALL (VM)
- Bytecode compiler with all opcodes including superinstructions
- 58 unit + integration tests
Makefile targets:
make test-all run Python (571) + C (58) tests
make examples run examples in both, compare output
make friction benchmark same .lsp in Python vs C
make c-build build C interpreter
make c-test run C tests
make c-repl C REPL
