Changes to m4/src/Attic/symtab.c,v [branch]

[Eric Blake]

CVSROOT:        /sources/m4
Module name:    m4
Branch:         branch
Changes by:     Eric Blake <ericb>      06/06/06 12:28:46

Index: src/symtab.c
===================================================================
RCS file: /sources/m4/m4/src/Attic/symtab.c,v
retrieving revision 1.1.1.1.2.4
retrieving revision 1.1.1.1.2.5
diff -u -b -r1.1.1.1.2.4 -r1.1.1.1.2.5
--- src/symtab.c        5 Jun 2006 12:41:30 -0000       1.1.1.1.2.4
+++ src/symtab.c        6 Jun 2006 12:28:46 -0000       1.1.1.1.2.5
@@ -147,18 +147,18 @@
   xfree ((voidstar) sym);
 }
 
-/*------------------------------------------------------------------------.
+/*-------------------------------------------------------------------.
 | Search in, and manipulation of the symbol table, are all done by       |
-| lookup_symbol ().  It basically hashes NAME to a list in the symbol    |
-| table, and searched this list for the first occurence of a symbol with  |
-| the name.                                                              |
+| lookup_symbol ().  It basically hashes NAME to a list in the      |
+| symbol table, and searches this list for the first occurrence of a |
+| symbol with the name.                                                     |
 |                                                                        |
-| The MODE parameter determines what lookup_symbol () will do.  It can   |
-| either just do a lookup, do a lookup and insert if not present, do an        
  |
-| insertion even if the name is already in the list, delete the first    |
-| occurrence of the name on the list or delete all occurences of the name |
-| on the list.                                                           |
-`------------------------------------------------------------------------*/
+| The MODE parameter determines what lookup_symbol () will do.  It   |
+| can either just do a lookup, do a lookup and insert if not        |
+| present, do an insertion even if the name is already in the list,  |
+| delete the first occurrence of the name on the list, or delete all |
+| occurrences of the name on the list.                              |
+`-------------------------------------------------------------------*/
 
 symbol *
 lookup_symbol (const char *name, symbol_lookup mode)
@@ -230,29 +230,64 @@
 
     case SYMBOL_DELETE:
 
-      /* Delete all occurences of symbols with NAME.  */
+      /* Delete all occurrences of symbols with NAME.  However, if symbol
+        is marked for tracing, leave a placeholder in the table.  */
 
       if (cmp != 0 || sym == NULL)
        return NULL;
-      do
+      {
+       boolean traced = SYMBOL_TRACED (sym);
+       while (SYMBOL_NEXT (sym) != NULL
+              && SYMBOL_SHADOWED (SYMBOL_NEXT (sym)))
+         {
+           *spp = SYMBOL_NEXT (sym);
+           free_symbol (sym);
+           sym = *spp;
+         }
+       if (traced)
+         {
+           if (SYMBOL_TYPE (sym) == TOKEN_TEXT)
+             xfree (SYMBOL_TEXT (sym));
+           SYMBOL_TYPE (sym) = TOKEN_VOID;
+           SYMBOL_TRACED (sym) = TRUE;
+           SYMBOL_SHADOWED (sym) = FALSE;
+         }
+       else
        {
          *spp = SYMBOL_NEXT (sym);
          free_symbol (sym);
          sym = *spp;
        }
-      while (sym != NULL && strcmp (name, SYMBOL_NAME (sym)) == 0);
+      }
       return NULL;
 
     case SYMBOL_POPDEF:
 
-       /* Delete the first occurence of a symbol with NAME.  */
+      /* Delete the first occurrence of a symbol with NAME.  However, if
+        symbol is marked for tracing, and this is the last copy, leave a
+        placeholder in the table.  */
 
       if (cmp != 0 || sym == NULL)
        return NULL;
-      if (SYMBOL_NEXT (sym) != NULL && cmp == 0)
+      if (SYMBOL_NEXT (sym) != NULL
+         && SYMBOL_SHADOWED (SYMBOL_NEXT (sym)))
+       {
        SYMBOL_SHADOWED (SYMBOL_NEXT (sym)) = FALSE;
+         SYMBOL_TRACED (SYMBOL_NEXT (sym)) = SYMBOL_TRACED (sym);
       *spp = SYMBOL_NEXT (sym);
       free_symbol (sym);
+       }
+      else if (SYMBOL_TRACED (sym))
+       {
+         if (SYMBOL_TYPE (sym) == TOKEN_TEXT)
+           xfree (SYMBOL_TEXT (sym));
+         SYMBOL_TYPE (sym) = TOKEN_VOID;
+       }
+      else
+       {
+         *spp = SYMBOL_NEXT (sym);
+         free_symbol (sym);
+       }
       return NULL;
 
     default: