pub fn ret_of(ty: Type, at: usize) -> Option<&'static str>Expand description
What the instruction that leaves a returned value in its register is called, for the value at that place in its own register file.
Keyed off the same two questions head_of asks, so a type this can give back is a type it can
take in. The place is the one a call counted to when it laid the return out, which is per file
rather than over the whole list: a structure of a double and a long gives both of them back
at place zero.
The register itself is not here. It is in the operand table in rucc_target::x86_64, which is
where the first one has always been, and the two names below are how a value says which of the
two it is. A convention with more than two registers to come back in would need more names, and
there is none, which is what the None at the end is about.