alt Hacker NewsThe example you set up was about f() calling into g() calling into h(). Why do you mention h() calling into g() now?
The whole thread is about how the traditional calling convention makes it difficult to implement TCO in C. Functions with different arity having different stack layout is indeed one of the roadblocks, so I think we agree here, no?
That was in response to a specific point that TCO needed callee-cleanup. But nobody cares about TCO in non-recursive call stacks, and nobody does cross-module recursion. Hence my question: if the only situation where anyone would care whether TCO is being performed is one in which the compiler can see both sides of the call, what does it matter what the calling convention is? The compiler is not bound to use any calling convention to generate the code for the call, it can just generate the caller and callee to be compatible with other and with no one else.