Re: DT_SYMBOLIC and -Bsymbolic

["Eric Youngdale" <eric@aib.com>]

On Jun 19, 10:58am, H.J. Lu wrote:
> Subject: Re: DT_SYMBOLIC and -Bsymbolic
> >
> > On Jun 19,  9:58am, H.J. Lu wrote:
> > > Subject: DT_SYMBOLIC and -Bsymbolic
> > > Hi,
> > >
> > > Do the current binutils snapshots and the Linux ELF dynamic
> > > linker support DT_SYMBOLIC? It should be easy to add -Bsymbolic
> > > to ld. The Linux ELF dynamic linker just needs to check the
> > > presence of DT_SYMBOLIC in the shared library to control the
> > > symbol binding. It is specified in the ELF doc, ELF.doc.tar.gz,
> > > on tsx-11 and sunsite in the linux gcc directory

	OK, I have patches to add this.  I basically assumed that all
that we needed to do was to translate -Bsymbolic on the link line into
DT_SYBMOLIC in the .dynamic section, and nothing more than that.  I tested
it with a small example, and it seemed to work.

-Eric




-- 
"The woods are lovely, dark and deep.  But I have promises to keep,
And lines to code before I sleep, And lines to code before I sleep."
--- ./bfd/elfcode.h.~1~	Tue May  2 23:43:07 1995
+++ ./bfd/elfcode.h	Mon Jun 19 13:30:16 1995
@@ -5141,11 +5141,13 @@
 
 boolean
 NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath,
-				     export_dynamic, info, sinterpptr)
+				     export_dynamic, symbolic,
+				     info, sinterpptr)
      bfd *output_bfd;
      const char *soname;
      const char *rpath;
      boolean export_dynamic;
+     boolean symbolic;
      struct bfd_link_info *info;
      asection **sinterpptr;
 {
@@ -5196,6 +5198,10 @@
 	      || ! elf_add_dynamic_entry (info, DT_SONAME, indx))
 	    return false;
 	}      
+
+      if (symbolic
+	  && ! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0))
+	    return false;
 
       if (rpath != NULL)
 	{
--- ./bfd/bfd-in.h.~1~	Tue Feb 21 21:00:44 1995
+++ ./bfd/bfd-in.h	Mon Jun 19 13:20:33 1995
@@ -551,7 +551,7 @@
 extern boolean bfd_elf64_record_link_assignment
   PARAMS ((bfd *, struct bfd_link_info *, const char *));
 extern boolean bfd_elf32_size_dynamic_sections
-  PARAMS ((bfd *, const char *, const char *, boolean,
+  PARAMS ((bfd *, const char *, const char *, boolean, boolean, 
 	   struct bfd_link_info *, struct sec **));
 extern boolean bfd_elf64_size_dynamic_sections
   PARAMS ((bfd *, const char *, const char *, boolean,
--- ./bfd/bfd-in2.h.~1~	Mon Apr 17 19:37:59 1995
+++ ./bfd/bfd-in2.h	Mon Jun 19 13:29:36 1995
@@ -551,7 +551,7 @@
 extern boolean bfd_elf64_record_link_assignment
   PARAMS ((bfd *, struct bfd_link_info *, const char *));
 extern boolean bfd_elf32_size_dynamic_sections
-  PARAMS ((bfd *, const char *, const char *, boolean,
+  PARAMS ((bfd *, const char *, const char *, boolean, boolean,
 	   struct bfd_link_info *, struct sec **));
 extern boolean bfd_elf64_size_dynamic_sections
   PARAMS ((bfd *, const char *, const char *, boolean,
--- ./ld/emultempl/elf32.em.~1~	Tue May  2 20:46:03 1995
+++ ./ld/emultempl/elf32.em	Mon Jun 19 12:43:07 1995
@@ -256,6 +256,7 @@
 					 command_line.soname,
 					 command_line.rpath,
 					 command_line.export_dynamic,
+					 command_line.symbolic,
 					 &link_info,
 					 &sinterp))
     einfo ("%P%F: failed to set dynamic section sizes: %E\n");
--- ./ld/lexsup.c.~1~	Tue May  2 23:43:14 1995
+++ ./ld/lexsup.c	Mon Jun 19 12:40:30 1995
@@ -86,7 +86,8 @@
 #define OPTION_SONAME			(OPTION_SHARED + 1)
 #define OPTION_SORT_COMMON		(OPTION_SONAME + 1)
 #define OPTION_STATS			(OPTION_SORT_COMMON + 1)
-#define OPTION_TBSS			(OPTION_STATS + 1)
+#define OPTION_SYMBOLIC			(OPTION_STATS + 1)
+#define OPTION_TBSS			(OPTION_SYMBOLIC + 1)
 #define OPTION_TDATA			(OPTION_TBSS + 1)
 #define OPTION_TTEXT			(OPTION_TDATA + 1)
 #define OPTION_TRADITIONAL_FORMAT	(OPTION_TTEXT + 1)
@@ -101,6 +102,7 @@
   static struct option longopts[] = {
     {"Bdynamic", no_argument, NULL, OPTION_CALL_SHARED},
     {"Bstatic", no_argument, NULL, OPTION_NON_SHARED},
+    {"Bsymbolic", no_argument, NULL, OPTION_SYMBOLIC},
     {"call_shared", no_argument, NULL, OPTION_CALL_SHARED},
     {"dc", no_argument, NULL, 'd'},
     {"defsym", required_argument, NULL, OPTION_DEFSYM},
@@ -356,6 +358,9 @@
 	  break;
 	case OPTION_STATS:
 	  config.stats = true;
+	  break;
+	case OPTION_SYMBOLIC:
+	  command_line.symbolic = true;
 	  break;
 	case 't':
 	  trace_files = true;
--- ./ld/ld.h.~1~	Tue Feb 21 21:02:28 1995
+++ ./ld/ld.h	Mon Jun 19 12:41:50 1995
@@ -69,6 +69,14 @@
   /* If true, build MIPS embedded PIC relocation tables in the output
      file.  */
   boolean embedded_relocs;
+
+  /*
+   * If true, we add a special dynamic entry in the output file telling
+   * the dynamic loader to search this file first, then other files
+   * for symbols.
+   */
+  boolean symbolic;
+
 } args_type;
 
 extern args_type command_line;
--- ./ld/ldmain.c.~1~	Fri Apr 14 00:12:18 1995
+++ ./ld/ldmain.c	Mon Jun 19 16:18:44 1995
@@ -171,6 +171,7 @@
   command_line.force_common_definition = false;
   command_line.interpreter = NULL;
   command_line.rpath = NULL;
+  command_line.symbolic = false;
 
   link_info.callbacks = &link_callbacks;
   link_info.relocateable = false;