[saagarjha]

My understanding is that CheerpX, but simulating a full userspace, can optimize all the way through system libraries, which are typically very general and have lots of code that is “dead” to your application. How would this approach fail for applications where the code tends to be more specific to the task?

[astrange]

Seeing through system libraries sounds problematic already, since some of them like libc violate aliasing when you can see their implementations, even in LLVM byte code form.

[carlopi]

I have to double check this, but the approach should be theoretically sound since we are quite strict with what functions are considered to have known call-sites: Function has to be internal (as in no visibility from outside) + no indirect uses (so no saving a pointer to the function somewhere). This should be enough to solve the problem you are thinking about.

[saagarjha]

That's actually a good point–more aggressive optimizations that peek through libraries that are not typically visible to the compiler are generally going to break things like allocators. Although, I guess something must be compiling them anyways, so perhaps it might end up OK?