Why would it need to be readable to be applicable to bootstrapping?
Some idealistic projects like live-bootstrap go a step further and don't even allow generated sources in the full source bootstrap chain, even if they are readable in principle, because the xz debacle showed that a configure script, which is also readable in principle, can contain a backdoor. In those projects you could probably still bootstrap Eurydice from sources, and then do the rust -> c translation of the rust compiler as an ordinary build step, before compiling it with a bootstrapped C compiler.
Wouldn't you want to audit the final outputs? Except nobody is going to bother analyzing my hand all the assembly produced by the final tool.
In other words, I am not seeing the value of pursuing the discovery of Thompson-style Trojans, no matter what the original source language was. It is one of these risks that one has to live with.
* compile “real” compiler with a different trusted compiler, producing “independent real compiler”
* compile the “real” compiler again using itself and the “independent compiler” - if the outputs don’t match, then you have detected the issue.
Source level transformation is a brilliant way to generate the “independent compiler”.
https://en.wikipedia.org/wiki/Backdoor_(computing)#Counterme...
Now, trust/security is one aspect of things, that's true...
But another important aspect of all of this is building understandable, maintainable, controllable software and AI's from the ground up, for future generations...
Let's suppose that in the future, there is no longer source code for compilers, they are only black-box compilers that future AI (which is also black-box by then) uses... At that point, humanity has lost control! No more source can be compiled without a black-box compiler, without an AI, and any source code so compiled will be controlled by whatever unknown things have been implanted in the original compiler!
Phrased another way, when humanity requires AI to generate new AI's (i.e., no scientists, computer scientists, programmers or other people know how to generate an AI from the ground up, from transistors on up, and control every layer of abstraction on top of that from assemblers to compilers to neural networks)... then humanity is lost, because at that point, humanity (not knowing how to build AI again from scratch, and control it at every step) quite literally has lost control of AI!
Future humanity cannot have that.
Future humanity requires, absolutely requires, transparency at every abstraction level... no black boxes should exist anywhere!
Future humanity also requires the requisite education, to be able to understand, manage and control each level of hardware/software abstraction, but that is outside of the scope of this HN post... :-)
Anyway, Stabbles, you get it!