// parseFunctions resolves function constants and it injects the
// necessary function prolog and epilog code.
//
// What the latter means, is that we analyze the registers being
// used. If any of them are registers that are guaranteed to
// be preserved across function calls, then we explicitly inject stack
// push/pop instructions to save their state.
//
// If there are any `return` instructions, we replace them with `set pc, $$`.
// Where `$$` is a label we generate which points to the function epilog.
func parseFunctions(ast *parser.AST) (err error) {
list := ast.Functions()
for i := range list {
if err = parseFuncConst(ast, list[i]); err != nil {
return
}
fixFunctionReturns(ast, list[i])
injectFunctionCode(ast, list[i])
}
return
}
