ld/ldindr.c

   1 /* ldindr.c
   2    Handle indirect symbols.
   3
   4    An indirect symbol is where a global symbol in one file say's that
   5    all refs like it should be turned into refs of the symbol pointed
   6    at by the value of the indirect symbol.
   7
   8    BFD supplies symbols to be indirected with the BFD_INDIRECT bit
   9    set. Whenever the linker gets one of these, it calls add_indirect
  10    with the symbol. We look up the symbol which this one dereferneces,
  11    and stop if they are the same. If they are not the same, copy all
  12    the information from the current to the dereffed symbol. Set the
  13    indirect bit in the flag. From now on the ldsym_get stuff will
  14    perform the indirection for us, at no charge.
  15 */
  16
  17
  18
  19 #include "bfd.h"
  20 #include "sysdep.h"
  21 #include "ld.h"
  22 #include "ldsym.h"
  23 #include "ldmisc.h"
  24
  25
  26
  27 static asymbol **
  28 DEFUN(move_it,(a_list, b_list),
  29 asymbol **a_list AND
  30 asymbol **b_list)
  31 {
  32   asymbol **head = a_list;
  33   asymbol **cursor = head;
  34
  35   if (a_list == 0) return b_list;
  36   if (b_list == 0) return a_list;
  37
  38   while (1) {
  39     asymbol *ptr = cursor[0];
  40     asymbol **next = (asymbol **)(ptr->udata);
  41     if (next == 0) {
  42       ptr->udata = (PTR) b_list;
  43       return head;
  44     }
  45     cursor = next;
  46   }
  47 }
  48
  49 #if 0
  50 void
  51 DEFUN(copy_over,(ldsym, bfdsym),
  52    ldsym_type *ldsym AND
  53    asymbol **bfdsym)
  54 {
  55   while (list && *list)
  56   {
  57     refize(Q_enter_global_ref(list, name);
  58     list = (asymbol **)((*list)->udata);
  59   }
  60 }
  61 #endif
  62
  63 /* This call allows us to change the symbol table so that all future
  64    refs to the symbol are patched to know the alias - but we still
  65    have to fix all the old ones */
  66 void
  67 DEFUN(add_indirect,(ptr),
  68 asymbol **ptr)
  69 {
  70   asymbol **p;
  71   ldsym_type *lgs = ldsym_get((*ptr)->name);
  72   ldsym_type *new = ldsym_get(((asymbol *)((*ptr)->value))->name);
  73
  74   /* If the mapping has already been done, stop now */
  75   if (lgs == new) return;
  76
  77   lgs->flags |= SYM_INDIRECT;
  78
  79   if (lgs->sdefs_chain && lgs->sdefs_chain[0])
  80   {
  81     einfo("indirect symbol already has definition %s",   lgs->sdefs_chain[0]);
  82   }
  83   new->scoms_chain = move_it(new->scoms_chain, lgs->scoms_chain);
  84   lgs->scoms_chain = 0;
  85   new->srefs_chain = move_it(new->srefs_chain, lgs->srefs_chain);
  86   lgs->srefs_chain = 0;
  87   new->sdefs_chain = move_it(new->sdefs_chain, lgs->sdefs_chain);
  88   lgs->sdefs_chain = 0;
  89
  90   /* If the result has any commons they should be turned into refs */
  91
  92   if (new->sdefs_chain && new->scoms_chain)
  93   {
  94     refize(new, new->scoms_chain);
  95   }
  96 lgs->sdefs_chain = (asymbol **)new;
  97
  98 }
  99
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