lang/pc/comp/tmpvar.C

   1 /* T E M P O R A R Y   V A R I A B L E S */
   2
   3 /*      Code for the allocation and de-allocation of temporary variables,
   4         allowing re-use.
   5         The routines use "ProcScope" instead of "CurrentScope", because
   6         "CurrentScope" also reflects WITH statements, and these scopes do not
   7         have local variables.
   8 */
   9
  10 #include        "debug.h"
  11
  12 #include        <alloc.h>
  13 #include        <em_arith.h>
  14 #include        <em_label.h>
  15 #include        <em_reg.h>
  16
  17 #include        "def.h"
  18 #include        "main.h"
  19 #include        "scope.h"
  20 #include        "type.h"
  21
  22 struct tmpvar   {
  23         struct tmpvar   *next;
  24         arith           t_offset;       /* offset from LocalBase */
  25 };
  26
  27 /* ALLOCDEF "tmpvar" 10 */
  28
  29 static struct tmpvar    *TmpInts,       /* for integer temporaries */
  30                         *TmpPtrs;       /* for pointer temporaries */
  31 static struct scope     *ProcScope;     /* scope of procedure in which the
  32                                            temporaries are allocated
  33                                         */
  34
  35 TmpOpen(sc)
  36         struct scope *sc;
  37 {
  38         /*      Initialize for temporaries in scope "sc".
  39         */
  40         ProcScope = sc;
  41 }
  42
  43 arith
  44 TmpSpace(sz, al)
  45         arith sz;
  46 {
  47         register struct scope *sc = ProcScope;
  48
  49         sc->sc_off = - WA(align(sz - sc->sc_off, al));
  50         return sc->sc_off;
  51 }
  52
  53 STATIC arith
  54 NewTmp(plist, sz, al, regtype, priority)
  55         struct tmpvar **plist;
  56         arith sz;
  57 {
  58         register arith offset;
  59         register struct tmpvar *tmp;
  60
  61         if( !*plist )   {
  62                 offset = TmpSpace(sz, al);
  63                 if( !options['n'] ) C_ms_reg(offset, sz, regtype, priority);
  64         }
  65         else    {
  66                 tmp = *plist;
  67                 offset = tmp->t_offset;
  68                 *plist = tmp->next;
  69                 free_tmpvar(tmp);
  70         }
  71         return offset;
  72 }
  73
  74 arith
  75 NewInt(reg_prior)
  76 {
  77         return NewTmp(&TmpInts, int_size, int_align, reg_any, reg_prior);
  78 }
  79
  80 arith
  81 NewPtr(reg_prior)
  82 {
  83    return NewTmp(&TmpPtrs, pointer_size, pointer_align, reg_pointer, reg_prior);
  84 }
  85
  86 STATIC
  87 FreeTmp(plist, off)
  88         struct tmpvar **plist;
  89         arith off;
  90 {
  91         register struct tmpvar *tmp = new_tmpvar();
  92
  93         tmp->next = *plist;
  94         tmp->t_offset = off;
  95         *plist = tmp;
  96 }
  97
  98 FreeInt(off)
  99         arith off;
 100 {
 101         FreeTmp(&TmpInts, off);
 102 }
 103
 104 FreePtr(off)
 105         arith off;
 106 {
 107         FreeTmp(&TmpPtrs, off);
 108 }
 109
 110 TmpClose()
 111 {
 112         register struct tmpvar *tmp, *tmp1;
 113
 114         tmp = TmpInts;
 115         while( tmp )    {
 116                 tmp1 = tmp;
 117                 tmp = tmp->next;
 118                 free_tmpvar(tmp1);
 119         }
 120         tmp = TmpPtrs;
 121         while( tmp )    {
 122                 tmp1 = tmp;
 123                 tmp = tmp->next;
 124                 free_tmpvar(tmp1);
 125         }
 126         TmpInts = TmpPtrs = 0;
 127 }