Update.

* dlfcn/dlfcn.h: Pretty print dladdr declaraction.

	* elf/rtld.c (process_envvars): Recognize LD_DYNAMIC_WEAK.
	(_dl_dynamic_weak): New variable.
	* elf/dl-support.c: Likewise.
	* sysdeps/generic/ldsodefs.h: Declare _dl_dynamic_weak.
	* elf/do-lookup.h: If we find a weak definition treat it like a
	normal symbol unless _dl_dynamic_weak is nonzero.  In the latter
	case treat it like before.

ChangeLog

@@ -1,5 +1,15 @@
 2000-06-07  Ulrich Drepper  <drepper@redhat.com>
 
+	* dlfcn/dlfcn.h: Pretty print dladdr declaraction.
+
+	* elf/rtld.c (process_envvars): Recognize LD_DYNAMIC_WEAK.
+	(_dl_dynamic_weak): New variable.
+	* elf/dl-support.c: Likewise.
+	* sysdeps/generic/ldsodefs.h: Declare _dl_dynamic_weak.
+	* elf/do-lookup.h: If we find a weak definition treat it like a
+	normal symbol unless _dl_dynamic_weak is nonzero.  In the latter
+	case treat it like before.
+
 	* elf/dl-addr.c (_dl_addr): Fill in correct information if symbol
 	is in main program.
 	* elf/Versions [ld] (GLIBC_2.2): Export _dl_argv.

dlfcn/dlfcn.h

@@ -67,15 +67,18 @@ extern void *dlvsym (void *__restrict __handle,
 extern char *dlerror (void) __THROW;
 
 #ifdef __USE_GNU
+/* Structure containing information about object searched using
+   `dladdr'.  */
+typedef struct
+{
+  __const char *dli_fname;	/* File name of defining object.  */
+  void *dli_fbase;		/* Load address of that object.  */
+  __const char *dli_sname;	/* Name of nearest symbol.  */
+  void *dli_saddr;		/* Exact value of nearest symbol.  */
+} Dl_info;
+
 /* Fill in *INFO with the following information about ADDRESS.
    Returns 0 iff no shared object's segments contain that address.  */
-typedef struct
-  {
-    __const char *dli_fname;	/* File name of defining object.  */
-    void *dli_fbase;		/* Load address of that object.  */
-    __const char *dli_sname;	/* Name of nearest symbol.  */
-    void *dli_saddr;		/* Exact value of nearest symbol.  */
-  } Dl_info;
 extern int dladdr (const void *__address, Dl_info *__info) __THROW;
 #endif
 

elf/dl-support.c

@@ -42,6 +42,7 @@ int _dl_debug_versions;
 int _dl_debug_reloc;
 int _dl_debug_files;
 int _dl_lazy;
+int _dl_dynamic_weak;
 
 /* If nonzero print warnings about problematic situations.  */
 int _dl_verbose;
@@ -107,6 +108,8 @@ non_dynamic_init (void)
 
   _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
 
+  _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
+
 #ifdef DL_PLATFORM_INIT
   DL_PLATFORM_INIT;
 #endif

elf/do-lookup.h

@@ -157,19 +157,23 @@ FCT (const char *undef_name, struct link_map *undef_map,
 	found_it:
 	  switch (ELFW(ST_BIND) (sym->st_info))
 	    {
+	    case STB_WEAK:
+	      /* Weak definition.  Use this value if we don't find another.  */
+	      if (__builtin_expect (_dl_dynamic_weak, 0))
+		{
+		  if (! result->s)
+		    {
+		      result->s = sym;
+		      result->m = map;
+		    }
+		  break;
+		}
+	      /* FALLTHROUGH */
 	    case STB_GLOBAL:
 	      /* Global definition.  Just what we need.  */
 	      result->s = sym;
 	      result->m = map;
 	      return 1;
-	    case STB_WEAK:
-	      /* Weak definition.  Use this value if we don't find another.  */
-	      if (! result->s)
-		{
-		  result->s = sym;
-		  result->m = map;
-		}
-	      break;
 	    default:
 	      /* Local symbols are ignored.  */
 	      break;

elf/rtld.c

@@ -87,6 +87,7 @@ const char *_dl_profile;
 const char *_dl_profile_output;
 struct link_map *_dl_profile_map;
 int _dl_lazy;
+int _dl_dynamic_weak;
 int _dl_debug_libs;
 int _dl_debug_impcalls;
 int _dl_debug_bindings;
@@ -1393,6 +1394,13 @@ process_envvars (enum mode *modep, int *lazyp)
 	  break;
 
 	case 12:
+	  /* The library search path.  */
+	  if (memcmp (&envline[3], "LIBRARY_PATH", 12) == 0)
+	    {
+	      library_path = &envline[16];
+	      break;
+	    }
+
 	  /* Where to place the profiling data file.  */
 	  if (memcmp (&envline[3], "DEBUG_OUTPUT", 12) == 0)
 	    {
@@ -1400,9 +1408,8 @@ process_envvars (enum mode *modep, int *lazyp)
 	      break;
 	    }
 
-	  /* The library search path.  */
-	  if (memcmp (&envline[3], "LIBRARY_PATH", 12) == 0)
-	    library_path = &envline[16];
+	  if (memcmp (&envline[3], "DYNAMIC_WEAK", 12) == 0)
+	    _dl_dynamic_weak = 1;
 	  break;
 
 	case 14:

sysdeps/generic/ldsodefs.h

@@ -189,6 +189,9 @@ extern int _dl_debug_fd;
 /* Names of shared object for which the RPATH should be ignored.  */
 extern const char *_dl_inhibit_rpath;
 
+/* Nonzero if references should be treated as weak during runtime linking.  */
+extern int _dl_dynamic_weak;
+
 /* OS-dependent function to open the zero-fill device.  */
 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */