> There is no particular need to rewrite existing C code, provided the same benefit can be obtained more cheaply by alternative implementations of C
To be clear, those "alternative implementations" do not exist, and no-one actually working on C compilers or tools to make C code safer has been able to produce one, or even come up with a credible plan for producing one.
"Fail-Safe C" is a research project that has been dead for ten years. Note:
> Some benchmark results show that the execution time are around 3 to 5 times of the original, natively-compiled programs, in avarage
That overhead is actually a lot higher than similar projects I also consider failures, such as CCured.
To be clear, when we talk about "an alternative implementation of C", it needs to give similar performance and other properties (e.g. function and data interop) to other C compilers. You can't impose a 3-5x slowdown and say "look, C is safe".
When everything else fails, kill the bug with hardware memory tagging spray.
> To be clear, when we talk about "an alternative implementation of C", it needs to give similar performance and other properties (e.g. function and data interop) to other C compilers. You can't impose a 3-5x slowdown and say "look, C is safe".
Pretty much every language (except rust) which claims to be "C but safe" has the same issue, except you have to rewrite your program in it.
A C interpreter is not exactly the sort of thing that the embedded software industry has been waiting to deploy in production.
Further, CHERI is not enough to achieve temporal memory safety, it only provides the primitive that one could use to implement an efficient, correct tracing GC.
Perhaps most importantly, one can not use CHERI today. It is just not an option. Memory safe languages exist, and have existed for quite some time.
Pointer tagging and other approaches like CHERI are very promising. Keeping in mind of course that they double the size of pointers and have a global runtime performance cost. Less ambitious but otherwise similar mitigations are already being adopted.
(Disclaimer: been there, done that, part of the CHERI team)
Best of luck with the research, I'm quite bullish on the work.