lang/pc/comp/scope.c

   1 /* S C O P E   M E C H A N I S M */
   2
   3 #include        "debug.h"
   4
   5 #include        <alloc.h>
   6 #include        <assert.h>
   7 #include        <em_arith.h>
   8 #include        <em_label.h>
   9
  10 #include        "LLlex.h"
  11 #include        "def.h"
  12 #include        "idf.h"
  13 #include        "misc.h"
  14 #include        "node.h"
  15 #include        "scope.h"
  16 #include        "type.h"
  17
  18 struct scope *GlobalScope, *PervasiveScope, *BlockScope;
  19 struct scopelist *CurrVis;
  20 extern int proclevel;                   /* declared in declar.g */
  21 static int sccount;
  22
  23 InitScope()
  24 {
  25         register struct scope *sc = new_scope();
  26         register struct scopelist *ls = new_scopelist();
  27
  28         sc->sc_level = proclevel;
  29         PervasiveScope = sc;
  30         ls->sc_scope = PervasiveScope;
  31         ls->sc_count = ++sccount;
  32         CurrVis = ls;
  33 }
  34
  35 open_scope()
  36 {
  37         register struct scope *sc = new_scope();
  38         register struct scopelist *ls = new_scopelist();
  39
  40         sc->sc_level = proclevel;
  41         ls->sc_scope = sc;
  42         ls->next = CurrVis;
  43         ls->sc_count = ++sccount;
  44         CurrVis = ls;
  45 }
  46
  47 close_scope(doclean)
  48 {
  49         /* When this procedure is called, the next visible scope is equal to
  50            the statically enclosing scope
  51         */
  52         register struct def *df;
  53
  54         assert(CurrentScope != 0);
  55         df = CurrentScope->sc_def;
  56         if (doclean) while (df) {
  57                 struct def *next = df->df_nextinscope;
  58                 if (! (df->df_flags & (D_VARPAR|D_VALPAR))) remove_def(df);
  59                 df = next;
  60         }
  61         CurrVis = CurrVis->next;
  62 }
  63
  64 Forward(nd, tp)
  65         register struct node *nd;
  66         register struct type *tp;
  67 {
  68         /* Enter a forward reference into the current scope. This is
  69          * used in pointertypes.
  70          */
  71         register struct def *df = define(nd->nd_IDF, CurrentScope, D_FORWTYPE);
  72         register struct forwtype *fw_type = new_forwtype();
  73
  74         fw_type->f_next = df->df_fortype;
  75         df->df_fortype = fw_type;
  76
  77         fw_type->f_node = nd;
  78         fw_type->f_type = tp;
  79 }
  80
  81 chk_prog_params()
  82 {
  83         /* the program parameters must be global variables of some file type */
  84         register struct def *df = CurrentScope->sc_def;
  85
  86         while( df )     {
  87             if( df->df_kind & D_PARAMETER )     {
  88                 if( !is_anon_idf(df->df_idf) )  {
  89                     if( df->df_type == error_type )
  90                          error("program parameter \"%s\" must be a global variable",
  91                                                         df->df_idf->id_text);
  92                     else if( df->df_type->tp_fund != T_FILE )
  93                         error("program parameter \"%s\" must have a file type",
  94                                                         df->df_idf->id_text);
  95
  96                     df->df_kind = D_VARIABLE;
  97                 }
  98                 else df->df_kind = D_ERROR;
  99             }
 100             df = df->df_nextinscope;
 101         }
 102 }
 103
 104 chk_directives()
 105 {
 106         /* check if all forward declarations are defined */
 107         register struct def *df = CurrentScope->sc_def;
 108
 109         while( df )     {
 110                 if( df->df_kind == D_FWPROCEDURE )
 111                      error("procedure \"%s\" not defined", df->df_idf->id_text);
 112                 else if( df->df_kind == D_FWFUNCTION )
 113                       error("function \"%s\" not defined", df->df_idf->id_text);
 114
 115                 df = df->df_nextinscope;
 116         }
 117 }