code review 4173041: peep: bug fix

src/cmd/5g/list.c

 // Derived from Inferno utils/5c/list.c
 // http://code.google.com/p/inferno-os/source/browse/utils/5c/list.c
 //
 //      Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
 //      Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
 //      Portions Copyright © 1997-1999 Vita Nuova Limited
 //      Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
 //      Portions Copyright © 2004,2006 Bruce Ellis
 //      Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
 //      Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
@@ skipping 69 matching lines @@
 int
 Dconv(Fmt *fp)
 {
         char str[STRINGSZ];
         char *op;
         Addr *a;
         int i;
         int32 v;
 
         a = va_arg(fp->args, Addr*);
+        if(a == A) {
+                sprint(str, "<nil>");
+                goto conv;
+        }
         i = a->type;
         switch(i) {
 
         default:
                 sprint(str, "GOK-type(%d)", a->type);
                 break;
 
         case D_NONE:
                 str[0] = 0;
                 if(a->name != D_NONE || a->reg != NREG || a->sym != S)
@@ skipping 76 matching lines @@
 
                 // TODO(kaib): Add back
 //      case D_ADDR:
 //              a->type = a->index;
 //              a->index = D_NONE;
 //              snprint(str, sizeof(str), "$%D", a);
 //              a->index = a->type;
 //              a->type = D_ADDR;
 //              goto conv;
         }
-//conv:
+conv:
         return fmtstrcpy(fp, str);
 }
 
 int
 Aconv(Fmt *fp)
 {
         int i;
 
         i = va_arg(fp->args, int);
         return fmtstrcpy(fp, anames[i]);
@@ skipping 121 matching lines @@
         case D_AUTO:
                 snprint(str, sizeof(str), "%S+%d(SP)", a->sym, a->offset);
                 break;
 
         case D_PARAM:
                 snprint(str, sizeof(str), "%S+%d(FP)", a->sym, a->offset);
                 break;
         }
         return fmtstrcpy(fp, str);
 }