2.9BSD - /usr/src/cmd/struct/3.loop.c

   1: #include <stdio.h>
   2: #include "def.h"
   3: #include "3.def.h"
   4: 
   5: #define ARCCOUNT(v) REACH(v)
   6: 
   7: 
   8: fixhd(v,hd,head)
   9: VERT v,hd,*head;
  10:     {
  11:     VERT w,newhd;
  12:     int i;
  13:     head[v] = hd;
  14:     newhd = (NTYPE(v) == ITERVX) ? v : hd;
  15:     for (i = 0; i < CHILDNUM(v); ++i)
  16:         for (w = LCHILD(v,i); DEFINED(w); w = RSIB(w))
  17:             fixhd(w,newhd,head);
  18:     }
  19: 
  20: getloop()
  21:     {
  22:     cntarcs();
  23:     fixloop(START);
  24:     }
  25: 
  26: 
  27: cntarcs()   /* count arcs entering each node */
  28:     {
  29:     VERT w,v;
  30:     int i;
  31:     for (v = 0; v < nodenum; ++v)
  32:         ARCCOUNT(v) = 0;
  33:     for (v = 0; v < nodenum; ++v)
  34:         for (i = 0; i < ARCNUM(v); ++i)
  35:             {
  36:             w = ARC(v,i);
  37:             if (!DEFINED(w)) continue;
  38:             ++ARCCOUNT(w);
  39:             }
  40:     }
  41: 
  42: 
  43: fixloop(v)      /* find WHILE loops  */
  44: VERT v;
  45:     {
  46:     int recvar;
  47:     if (NTYPE(v) == LOOPVX)
  48:         {
  49:         ASSERT(DEFINED(ARC(v,0)),fixloop);
  50:         NXT(ARC(v,0)) = ARC(v,0);
  51:         if (!getwh(v))
  52:             getun(v);
  53:         }
  54:     else if (NTYPE(v) == IFVX && arbcase)
  55:         getswitch(v);
  56:     else if (NTYPE(v)==DOVX)
  57:         {
  58:         ASSERT(DEFINED(ARC(v,0)),fixloop);
  59:         NXT(ARC(v,0))=ARC(v,0);
  60:         }
  61:     RECURSE(fixloop,v,recvar);
  62:     }
  63: 
  64: 
  65: getwh(v)
  66: VERT v;
  67:     {
  68:     VERT vchild, vgrand,vgreat;
  69:     ASSERT(NTYPE(v) == LOOPVX,getwh);
  70:     vchild = LCHILD(v,0);
  71:     ASSERT(DEFINED(vchild),getwh);
  72:     ASSERT(NTYPE(vchild) == ITERVX,getwh);
  73:     vgrand = LCHILD(vchild,0);
  74:     if (!DEFINED(vgrand) || !IFTHEN(vgrand) )
  75:         return(FALSE);
  76:     vgreat = LCHILD(vgrand,THEN);
  77:     if (DEFINED(vgreat) && NTYPE(vgreat) == GOVX && ARC(vgreat,0) == BRK(vchild))
  78:         {
  79:         /* turn into WHILE */
  80:         NTYPE(v) = WHIVX;
  81:         NEG(vgrand) = !NEG(vgrand);
  82:         LPRED(vchild) = vgrand;
  83:         LCHILD(vchild,0) = RSIB(vgrand);
  84:         RSIB(vgrand) = UNDEFINED;
  85:         return(TRUE);
  86:         }
  87:     return(FALSE);
  88:     }
  89: 
  90: 
  91: 
  92: getun(v)        /* change loop to REPEAT UNTIL if possible */
  93: VERT v;
  94:     {
  95:     VERT vchild, vgrand,  vgreat, before, ch;
  96:     ASSERT(NTYPE(v) == LOOPVX,getun);
  97:     vchild = LCHILD(v,0);
  98:     ASSERT(DEFINED(vchild), getun);
  99:     if (ARCCOUNT(vchild) > 2)
 100:         return(FALSE);      /* loop can be iterated without passing through predicate of UNTIL */
 101:     vgrand = ARC(vchild,0);
 102:     if (!DEFINED(vgrand))
 103:         return(FALSE);
 104:     for (ch = vgrand,before = UNDEFINED; DEFINED(RSIB(ch)); ch = RSIB(ch))
 105:         before = ch;
 106:     if (!IFTHEN(ch))
 107:         return(FALSE);
 108:     vgreat = LCHILD(ch,THEN);
 109:     if (DEFINED(vgreat) && NTYPE(vgreat) == GOVX && ARC(vgreat,0) == BRK(vchild))
 110:         {
 111:         /* create  UNTIL node */
 112:         NTYPE(v) = UNTVX;
 113:         NXT(vchild) = ch;
 114:         LPRED(vchild)=ch;
 115:         RSIB(before) = UNDEFINED;
 116:         return(TRUE);
 117:         }
 118:     return(FALSE);
 119:     }
 120: 
 121: 
 122: #define FORMCASE(w) (DEFINED(w) && !DEFINED(RSIB(w)) && NTYPE(w) == IFVX && ARCCOUNT(w) == 1)
 123: 
 124: getswitch(v)
 125: VERT v;
 126:     {
 127:     VERT ch, grand, temp;
 128:     /* must be of form if ... else if ... else if ... */
 129:     if (NTYPE(v) != IFVX) return(FALSE);
 130:     ch = LCHILD(v,ELSE);
 131:     if (!FORMCASE(ch)) return(FALSE);
 132:     grand = LCHILD(ch,ELSE);
 133:     if (!FORMCASE(grand)) return(FALSE);
 134: 
 135:     temp = create(SWCHVX,0);
 136:     exchange(&graph[temp],&graph[v]);   /* want arcs to enter switch, not first case*/
 137:     BEGCOM(v) = UNDEFINED;
 138:     RSIB(v) = RSIB(temp);       /* statements which followed IFVX should follow switch */
 139:     EXP(v) = UNDEFINED;
 140:     LCHILD(v,0) = temp;
 141:     NTYPE(temp) = ACASVX;
 142:     for (ch = LCHILD(temp,ELSE); FORMCASE(ch); )
 143:         {
 144:         LCHILD(temp,ELSE) = UNDEFINED;
 145:         RSIB(temp) = ch;
 146:         NTYPE(ch) = ACASVX;
 147:         temp = ch;
 148:         ch = LCHILD(temp,ELSE);
 149:         }
 150:     ASSERT(!DEFINED(RSIB(temp)),getswitch);
 151:     return(TRUE);
 152:     }

Defined functions

Defined macros