This is false. There are multiple safe C implementations. compcert and https://staff.aist.go.jp/y.oiwa/FailSafeC/index-en.html are two such.
"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.