15.3.146  src/lib/compiler/back/low/regor/liveness.api

## liveness.api  -- Computing live variables.

# Compiled by:
#     src/lib/compiler/back/low/lib/lowhalf.lib

stipulate
    package iht =  int_hashtable;                                               # int_hashtable                 is from   src/lib/src/int-hashtable.pkg
    package rkj =  registerkinds_junk;                                          # registerkinds_junk            is from   src/lib/compiler/back/low/code/registerkinds-junk.pkg
herein

    api Liveness {
        #
        package mcg: Machcode_Controlflow_Graph;                                        # Machcode_Controlflow_Graph    is from   src/lib/compiler/back/low/mcg/machcode-controlflow-graph.api

        Liveness_Table
            = 
            iht::Hashtable(  rkj::cos::Colorset  );

        Du = ( List( rkj::Codetemp_Info ),                              # "du" == "definition/use"
               List( rkj::Codetemp_Info )
             );

        # One def/use step (given def/use function, take du after instruction
        # to du before instruction
        #
        du_step:  (mcg::mcf::Machine_Op -> Du)
                  ->
                  (mcg::mcf::Machine_Op,   Du)
                  ->
                  Du;

        # One step for liveness (on a per-instruction basis)
        #
        live_step:  (mcg::mcf::Machine_Op -> Du)
                    ->
                    (mcg::mcf::Machine_Op, rkj::cos::Colorset)
                    ->
                    rkj::cos::Colorset;

        liveness:  { def_use:                           mcg::mcf::Machine_Op -> Du,
                     #
                     get_codetemps_of_our_kind:         rkj::cls::Codetemplists -> List( rkj::Codetemp_Info )
                   }
                   ->
                   mcg::Machcode_Controlflow_Graph 
                   ->
                   { live_in:   Liveness_Table,
                     live_out:  Liveness_Table
                   };

    };
end;