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[PATCH] Fix DT_NEEDED search with --as-needed libraries (PR ld/2721)

Jakub Jelinek jakub@redhat.com
Thu Jun 1 15:26:00 GMT 2006 
Hi!

If some --as-needed library mentioned on the command line isn't directly
needed by executable being linked, but it is mentioned in DT_NEEDED of some
needed library, then without this patch ld will disregard the library
mentioned on the command line and look for a different one (e.g. in system
paths).

2006-06-01  Jakub Jelinek  <jakub@redhat.com>

	PR ld/2721
	* emultempl/elf32.em (global_found_as_needed): New variable.
	(gld${EMULATION_NAME}_check_needed): Succeed even for DYN_AS_NEEDED
	libraries.
	(gld${EMULATION_NAME}_after_open): If needed library is already
	loaded with DYN_AS_NEEDED flag set, try to open that library again.

--- ld/emultempl/elf32.em.jj	2006-06-01 15:50:34.000000000 +0200
+++ ld/emultempl/elf32.em	2006-06-01 16:55:02.000000000 +0200
@@ -149,6 +149,7 @@ cat >>e${EMULATION_NAME}.c <<EOF
 static struct bfd_link_needed_list *global_needed;
 static struct stat global_stat;
 static bfd_boolean global_found;
+static const char *global_found_as_needed;
 static struct bfd_link_needed_list *global_vercheck_needed;
 static bfd_boolean global_vercheck_failed;
 
@@ -809,7 +810,9 @@ cat >>e${EMULATION_NAME}.c <<EOF
 static void
 gld${EMULATION_NAME}_check_needed (lang_input_statement_type *s)
 {
-  if (global_found)
+  const char *found_as_needed = NULL;
+
+  if (global_found && global_found_as_needed == NULL)
     return;
 
   /* If this input file was an as-needed entry, and wasn't found to be
@@ -817,7 +820,11 @@ gld${EMULATION_NAME}_check_needed (lang_
   if (s->as_needed
       && (s->the_bfd == NULL
 	  || (bfd_elf_get_dyn_lib_class (s->the_bfd) & DYN_AS_NEEDED) != 0))
-    return;
+    {
+      if (global_found || s->filename == NULL)
+	return;
+      found_as_needed = s->filename;
+    }
 
   if (s->filename != NULL)
     {
@@ -826,6 +833,7 @@ gld${EMULATION_NAME}_check_needed (lang_
       if (strcmp (s->filename, global_needed->name) == 0)
 	{
 	  global_found = TRUE;
+	  global_found_as_needed = found_as_needed;
 	  return;
 	}
 
@@ -836,6 +844,7 @@ gld${EMULATION_NAME}_check_needed (lang_
 	      && strcmp (f + 1, global_needed->name) == 0)
 	    {
 	      global_found = TRUE;
+	      global_found_as_needed = found_as_needed;
 	      return;
 	    }
 	}
@@ -850,6 +859,7 @@ gld${EMULATION_NAME}_check_needed (lang_
 	  && strcmp (soname, global_needed->name) == 0)
 	{
 	  global_found = TRUE;
+	  global_found_as_needed = found_as_needed;
 	  return;
 	}
     }
@@ -886,6 +896,7 @@ gld${EMULATION_NAME}_after_open (void)
       struct bfd_link_needed_list *ll;
       struct dt_needed n, nn;
       int force;
+      const char *found_as_needed;
 
       /* If the lib that needs this one was --as-needed and wasn't
 	 found to be needed, then this lib isn't needed either.  */
@@ -906,8 +917,14 @@ gld${EMULATION_NAME}_after_open (void)
       global_needed = l;
       global_found = FALSE;
       lang_for_each_input_file (gld${EMULATION_NAME}_check_needed);
+      found_as_needed = NULL;
       if (global_found)
-	continue;
+	{
+	  if (global_found_as_needed == NULL)
+	    continue;
+	  else
+	    found_as_needed = global_found_as_needed;
+	}
 
       n.by = l->by;
       n.name = l->name;
@@ -944,6 +961,13 @@ EOF
 fi
 cat >>e${EMULATION_NAME}.c <<EOF
 
+	  if (found_as_needed != NULL)
+	    {
+	      nn.name = found_as_needed;
+	      if (gld${EMULATION_NAME}_try_needed (&nn, force))
+		break;
+	    }
+
 	  if (gld${EMULATION_NAME}_search_needed (command_line.rpath_link,
 						  &n, force))
 	    break;

	Jakub
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