pub fn heads() -> Vec<(Opcode, &'static str)>Expand description
Every name this module can give an instruction, with the opcode it gives it to.
This is what a rule file could be written about, so that the back end’s coverage check can ask what one
is written about and say where the difference is. It comes out of the same functions
head_of asks rather than out of a list, because a list of names checked against another
list of names is a test that both were typed the same way, which is not the question worth
asking.
The sweep is over every type the compiler has, including the ones nothing here has a name for. A width with no name contributes nothing and costs nothing, and the day one of them gets a name it appears here without anybody remembering to add it, which is the property that makes this worth generating rather than writing down.