motiejus/jakstys.lt
1
Fork 0
Code Releases Activity

more zig bootstrap updates

Browse Source
This commit is contained in:
Motiejus Jakštys 2024-11-12 23:54:20 +02:00
parent 23e0f39506
commit a240d21fca
1 changed files with 20 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
content/log/2024/zig-reproduced-without-binaries.md
View File

@ -5,10 +5,10 @@ slug: zig-reproduced-without-binaries
draft: true
---
I decided to bootstrap zig without using binaries that are [checked in the
I decided to bootstrap Zig without using binaries that are [checked in the
repository](https://github.com/ziglang/zig/blob/0.13.0/stage1/zig1.wasm) and
answer if the resulting `zig1.wasm` in the latest zig release (0.13.0) is the
same the one bootstrapped without those binaries.
answer if the resulting `zig1.wasm` in the latest Zig release (0.13.0) is the
same the one bootstrapped without using those binaries.
TLDR: yes, they are the same:
@ -20,7 +20,7 @@ $ sha256sum code/zig{,2}/stage1/zig1.wasm
I can now confidently say (and you can also check, you don't need to [trust
me][2]) that there is nothing hiding in `zig1.wasm` that hasn't been
checked-in.
checked-in as a source file.
Many, many thanks to [Hilton Chain][1] for reasons I that will become clear
later. The rest of this post walks through how I arrived to this claim.
@ -28,7 +28,7 @@ later. The rest of this post walks through how I arrived to this claim.
# Official zig1.wasm
Steps to acquire the official incarnation of `zig1.wasm` are straightforward:
download zig, build `zig3` using the official instructions, use it to
download Zig, build `zig3` using the official instructions, use it to
`update-zig1`:
```
@ -36,7 +36,7 @@ git clone https://github.com/ziglang/zig; cd zig
git checkout 0.13.0
mkdir build; pushd build
cmake ..
make -j install
make -j$(nproc) install
popd
build/stage3/bin/zig build update-zig1
```
@ -49,8 +49,7 @@ $ git diff --stat
1 file changed, 0 insertions(+), 0 deletions(-)
```
We will be comparing this `zig1.wasm` to the one bootstrapped in the next
section.
We will be comparing this file to the one bootstrapped in the next section.
# Binary-free zig1.wasm
@ -74,12 +73,12 @@ Date: 2022-11-13T01:35:20+02:00
1 file changed, 0 insertions(+), 0 deletions(-)
```
[Andrew's motivation][3] is legit from a Zig developer's perspective. However,
checked-in binary blobs have trust issues, regardless of what we think about
the author.
[Andrew's motivation][3] is reasonable from a Zig developer's perspective.
However, checked-in binary blobs have trust issues, regardless of what we think
about the author.
The last commit that can[^1] be built without binary blobs is the parent of
this one:
The last commit that can[^1] be built without using binary blobs is the parent
of this one:
```
commit 28514476ef8c824c3d189d98f23d0f8d23e496ea
@ -92,21 +91,20 @@ Date: 2022-11-01T05:29:55+02:00
use stage1 as a backend anymore.
```
Once C++ implementation was removed, Zig is required to build Zig. This is a
cyclic dependency, which Zig Core team breaks by continuously checking in *a*
Zig implementation in wasm, the `zig1.wasm` file, which is used to build the
compiler.
After this, Zig is required to build Zig. This is a cyclic dependency, which
Zig Core team breaks by continuously checking in *a* Zig compiler in
wasm, the `zig1.wasm` file, which is used to build the compiler.
Andrew suggests a motivated third-party to implement a [Zig
interpreter][zig-interpreter] in non-zig that could break this chain. While
interpreter][zig-interpreter] in non-Zig that could break this chain. While
that would be certainly be ideal, nobody has built it yet 🤷.
The steps to build "trusted"[^3] zig are roughly:
The steps to build "trusted"[^3] Zig are roughly:
1. Build zig from the C++ implementation of the commit above (with hacks and
1. Build Zig from the C++ implementation of the commit above (with hacks and
tricks to make it [actually compile][4]).
2. Use previous step to build the first Zig self-hosted.
3. Proceed to the next step. When the updated zig does not build, find creative
3. Proceed to the next step. When the updated Zig does not build, find creative
ways to build it anyway (or, when really stuck, ask @mlugg).
4. Goto 2 for [45+ times][5].
@ -131,7 +129,7 @@ $ ls -lh /gnu/store/kqwq8sjgwi561sp78vfi6xkgm9i3wysk-zig-0.13.0-zig1/bin/zig1.wa
```
Once I had `zig1.wasm` of 0.13.0, I did the same as I did in the official
`zig1.wasm`: built zig3, used it to build `zig1.wasm`, and voilà, the hashes of
`zig1.wasm`: built `zig3`, used it to build `zig1.wasm`, and voilà, the hashes of
the official `zig1.wasm` and the one built here match.
# Conclusion