1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
#+TITLE: Bootstrapping, reproducibility, etc.
#+AUTHOR: Vincent Ambo
#+DATE: <2018-03-10 Sat>
* Compiler bootstrapping
This section contains notes about compiler bootstrapping, the
history thereof, which compilers need it - and so on:
** C
** Haskell
- self-hosted compiler (GHC)
** Common Lisp
CL is fairly interesting in this space because it is a language
that is defined via an ANSI standard that compiler implementations
normally actually follow!
CL has several ecosystem components that focus on making
abstracting away implementation-specific calls and if a self-hosted
compiler is written in CL using those components it can be
cross-bootstrapped.
** Python
* A note on runtimes
Sometimes the compiler just isn't enough ...
** LLVM
** JVM
* References
https://github.com/mame/quine-relay
https://manishearth.github.io/blog/2016/12/02/reflections-on-rusting-trust/
https://tests.reproducible-builds.org/debian/reproducible.html
* Slide thoughts:
1. Hardware trust has been discussed here a bunch, most recently
during the puri.sm talk. Hardware trust is important, as we see
with IME, but it's striking that people often take a leap to "I'm
now on my trusted Debian with free software".
Unless you built it yourself from scratch (Spoiler: you haven't)
you're placing trust in what is basically foreign binary blobs.
Agenda: Implications/attack vectors of this, state of the chicken
& egg, the topic of reproducibility, what can you do? (Nix!)
2. Chicken-and-egg issue
It's an important milestone for a language to become self-hosted:
You begin doing a kind of dogfeeding, you begin to enforce
reliability & consistency guarantees to avoid having to redo your
own codebase constantly and so on.
However, the implication is now that you need your own compiler
to compile itself.
Common examples:
- C/C++ compilers needed to build C/C++ compilers:
GCC 4.7 was the last version of GCC that could be built with a
standard C-compiler, nowadays it is mostly written in C++.
Certain versions of GCC can be built with LLVM/Clang.
Clang/LLVM can be compiled by itself and also GCC.
- Rust was originally written in OCAML but moved to being
self-hosted in 2011. Currently rustc-releases are always built
with a copy of the previous release.
It's relatively new so we can build the chain all the way.
Notable exceptions: Some popular languages are not self-hosted,
for example Clojure. Languages also have runtimes, which may be
written in something else (e.g. Haskell -> C runtime)
* How to help:
Most of this advice is about reproducible builds, not bootstrapping,
as that is a much harder project.
- fix reproducibility issues listed in Debian's issue tracker (focus
on non-Debian specific ones though)
- experiment with NixOS / GuixSD to get a better grasp on the
problem space of reproducibility
If you want to contribute to bootstrapping, look at
bootstrappable.org and their wiki. Several initiatives such as MES
could need help!
|
