From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Lance Taylor <ian@zembu.com>
To: hjl@varesearch.com
Cc: binutils@sourceware.cygnus.com, geoffk@ozemail.com.au
Subject: Re: A weak symbol patch
Date: Wed, 07 Jul 1999 11:20:00 -0000
Message-id: <19990707181919.2961.qmail@daffy.airs.com>
References: <19990706203412.DAA553FC1@varesearch.com>
X-SW-Source: 1999-q3/msg00062.html

   Date: Tue, 6 Jul 1999 13:34:12 -0700 (PDT)
   From: hjl@varesearch.com (H.J. Lu)

   I believe there is a linker bug regarding the weak symbol handling. I
   have sent 2 testcases for the bug. Here is a patch. Could you please
   take a look?

I am about to check in the appended patch, which is based on yours.  I
think this will fix your test case.

Ian

Index: elflink.h
===================================================================
RCS file: /cvs/binutils/binutils/bfd/elflink.h,v
retrieving revision 1.9
diff -u -r1.9 elflink.h
--- elflink.h	1999/07/01 23:20:07	1.9
+++ elflink.h	1999/07/07 18:18:39
@@ -492,14 +492,19 @@
      represent variables; this can cause confusion in principle, but
      any such confusion would seem to indicate an erroneous program or
      shared library.  We also permit a common symbol in a regular
-     object to override a weak symbol in a shared object.  */
+     object to override a weak symbol in a shared object.
 
+     We prefer a non-weak definition in a shared library to a weak
+     definition in the executable.  */
+
   if (newdyn
       && newdef
       && (olddef
 	  || (h->root.type == bfd_link_hash_common
 	      && (bind == STB_WEAK
-		  || ELF_ST_TYPE (sym->st_info) == STT_FUNC))))
+		  || ELF_ST_TYPE (sym->st_info) == STT_FUNC)))
+      && (h->root.type != bfd_link_hash_defweak
+	  || bind == STB_WEAK))
     {
       *override = true;
       newdef = false;
@@ -543,7 +548,10 @@
 
      As above, we again permit a common symbol in a regular object to
      override a definition in a shared object if the shared object
-     symbol is a function or is weak.  */
+     symbol is a function or is weak.
+
+     As above, we permit a non-weak definition in a shared object to
+     override a weak definition in a regular object.  */
 
   if (! newdyn
       && (newdef
@@ -552,7 +560,9 @@
 		  || h->type == STT_FUNC)))
       && olddyn
       && olddef
-      && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0)
+      && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
+      && (bind != STB_WEAK
+	  || h->root.type == bfd_link_hash_defweak))
     {
       /* Change the hash table entry to undefined, and let
 	 _bfd_generic_link_add_one_symbol do the right thing with the
@@ -626,6 +636,31 @@
       h->verinfo.vertree = NULL;
     }
 
+  /* Handle the special case of a weak definition in a regular object
+     followed by a non-weak definition in a shared object.  In this
+     case, we prefer the definition in the shared object.  To make
+     this work we have to frob the flags.  */
+  if (olddef
+      && ! olddyn
+      && h->root.type == bfd_link_hash_defweak
+      && newdef
+      && newdyn
+      && bind != STB_WEAK)
+    h->elf_link_hash_flags &= ~ ELF_LINK_HASH_DEF_REGULAR;
+
+  /* Handle the special case of a non-weak definition in a shared
+     object followed by a weak definition in a regular object.  In
+     this case we prefer to definition in the shared object.  To make
+     this work we have to tell the caller to not treat the new symbol
+     as a definition.  */
+  if (olddef
+      && olddyn
+      && h->root.type != bfd_link_hash_defweak
+      && newdef
+      && ! newdyn
+      && bind == STB_WEAK)
+    *override = true;
+
   return true;
 }