[patch] SymbianOS Arm executables

[Paul Brook <paul at codesourcery dot com>]

arm-*-symbianelf executables are relocatable. This has a few implications:

- We need to write out absolute relocations, like we do with shared libraries.
- These need to be against a symbols because the RO and RW segments are 
relocated independently. In most cases we use the section symbol.
- Imported data is addressed directly (with absolute relocations).

Most of the changes are arm-specific, however I did need to add a new 
common-code flag to allow creation of the local dynamic symbols.

Tested on i686-linux, arm-none-eabi and arm-none-symbianelf.
Ok?

Paul

This depends on a previous patch for correct symbol ordering:
http://sourceware.org/ml/binutils/2005-02/msg00169.html

2005-02-09  Paul Brook  <paul@codesourcery.com>

 * elf-bfd.h (struct elf_link_hash_table): Add keep_local_dynsyms.
 * elf.c (_bfd_elf_link_hash_table_init): Initialize it.
 * elflink.c (bfd_elf_link_record_dynamic_symbol): Allow creation of
 local dynamic symbols.
 (bfd_elf_record_link_assignment): Allow creation of dynamic section
 symbols in ecxecutables.
 (_bfd_elf_link_renumber_dynsyms): Ditto.
 (bfd_elf_final_link): Ditto.
 * elf32-arm.c (elf32_arm_final_link_relocate): Copy absolute
 relocations into SymbianOS executables.
 (elf32_arm_check_relocs): Crate dynamic sections for SymbianOS
 executables.  Copy absolute relocations into SymbianOS executables.
 (elf32_arm_adjust_dynamic_symbol): Don't create copy relocations
 in symbian objects.
 (allocate_dynrelocs): Copy relocations for SymbianOS executables.
 Output dynamic symbols for symbols defined in linker scripts.

Index: bfd/elf-bfd.h
===================================================================
RCS file: /var/cvsroot/src-cvs/src/bfd/elf-bfd.h,v
retrieving revision 1.170
diff -u -p -r1.170 elf-bfd.h
--- bfd/elf-bfd.h	31 Jan 2005 22:53:24 -0000	1.170
+++ bfd/elf-bfd.h	9 Feb 2005 02:20:12 -0000
@@ -398,6 +398,10 @@ struct elf_link_hash_table
 
   /* A linked list of BFD's loaded in the link.  */
   struct elf_link_loaded_list *loaded;
+
+  /* True if local symbols should be included in dynamic symbol tables
+     of executable objects.  */
+  bfd_boolean keep_local_dynsyms;
 };
 
 /* Look up an entry in an ELF linker hash table.  */
Index: bfd/elf.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/bfd/elf.c,v
retrieving revision 1.263
diff -u -p -r1.263 elf.c
--- bfd/elf.c	31 Jan 2005 23:13:18 -0000	1.263
+++ bfd/elf.c	9 Feb 2005 02:03:46 -0000
@@ -1493,6 +1493,7 @@ _bfd_elf_link_hash_table_init
   table->tls_sec = NULL;
   table->tls_size = 0;
   table->loaded = NULL;
+  table->keep_local_dynsyms = FALSE;
 
   ret = _bfd_link_hash_table_init (&table->root, abfd, newfunc);
   table->root.type = bfd_link_elf_hash_table;
Index: bfd/elf32-arm.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/bfd/elf32-arm.c,v
retrieving revision 1.20
diff -u -p -r1.20 elf32-arm.c
--- bfd/elf32-arm.c	31 Jan 2005 17:50:20 -0000	1.20
+++ bfd/elf32-arm.c	9 Feb 2005 02:23:36 -0000
@@ -2352,7 +2352,7 @@ elf32_arm_final_link_relocate (reloc_how
 
       /* When generating a shared object, these relocations are copied
 	 into the output file to be resolved at run time.  */
-      if (info->shared
+      if ((info->shared || globals->symbian_p)
 	  && (input_section->flags & SEC_ALLOC)
 	  && (r_type != R_ARM_REL32
 	      || !SYMBOL_CALLS_LOCAL (info, h))
@@ -3985,6 +3985,14 @@ elf32_arm_check_relocs (bfd *abfd, struc
   htab = elf32_arm_hash_table (info);
   sreloc = NULL;
 
+  /* Create dynamic sections for SymbianOS executables so that we can
+     copy relocations.  */
+  if (htab->symbian_p && ! htab->root.dynamic_sections_created)
+    {
+      if (! _bfd_elf_link_create_dynamic_sections (abfd, info))
+	return FALSE;
+    }
+
   dynobj = elf_hash_table (info)->dynobj;
   local_got_offsets = elf_local_got_offsets (abfd);
 
@@ -4117,7 +4125,7 @@ elf32_arm_check_relocs (bfd *abfd, struc
                later (it is never cleared).  We account for that
                possibility below by storing information in the
                relocs_copied field of the hash table entry.  */
-	    if (info->shared
+	    if ((info->shared || htab->symbian_p)
 		&& (sec->flags & SEC_ALLOC) != 0
 		&& ((r_type != R_ARM_PC24
 		     && r_type != R_ARM_PLT32
@@ -4377,7 +4385,9 @@ elf32_arm_adjust_dynamic_symbol (struct 
   asection * s;
   unsigned int power_of_two;
   struct elf32_arm_link_hash_entry * eh;
+  struct elf32_arm_link_hash_table *globals;
 
+  globals = elf32_arm_hash_table (info);
   dynobj = elf_hash_table (info)->dynobj;
 
   /* Make sure we know what is going on here.  */
@@ -4442,8 +4452,10 @@ elf32_arm_adjust_dynamic_symbol (struct 
   /* If we are creating a shared library, we must presume that the
      only references to the symbol are via the global offset table.
      For such cases we need not do anything here; the relocations will
-     be handled correctly by relocate_section.  */
-  if (info->shared)
+     be handled correctly by relocate_section.  On SymbianOS executables
+     can reference data in shared objects directly, so we don't need to
+     do anything here.  */
+  if (info->shared || globals->symbian_p)
     return TRUE;
 
   /* We must allocate the symbol in our .dynbss section, which will
@@ -4636,13 +4648,23 @@ allocate_dynrelocs (struct elf_link_hash
      space for pc-relative relocs that have become local due to symbol
      visibility changes.  */
 
-  if (info->shared)
+  if (info->shared || htab->symbian_p)
     {
       /* Discard relocs on undefined weak syms with non-default
          visibility.  */
       if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
 	  && h->root.type == bfd_link_hash_undefweak)
 	eh->relocs_copied = NULL;
+      else if (htab->symbian_p && h->dynindx == -1
+	       && h->root.type == bfd_link_hash_new)
+	{
+	  /* Output absolute symbols so that we can create relocations
+	     against them.  For normal symbols we output a relocation
+	     against the section that contains them.  */
+	  if (! bfd_elf_link_record_dynamic_symbol (info, h))
+	    return FALSE;
+	}
+
     }
   else
     {
@@ -5845,6 +5867,7 @@ elf32_arm_symbian_link_hash_table_create
       /* The PLT entries are each three instructions.  */
       htab->plt_entry_size = 4 * NUM_ELEM (elf32_arm_symbian_plt_entry);
       htab->symbian_p = 1;
+      htab->root.keep_local_dynsyms = 1;
     }
   return ret;
 }     
Index: bfd/elflink.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/bfd/elflink.c,v
retrieving revision 1.126
diff -u -p -r1.126 elflink.c
--- bfd/elflink.c	1 Feb 2005 01:11:14 -0000	1.126
+++ bfd/elflink.c	9 Feb 2005 02:07:31 -0000
@@ -386,7 +386,8 @@ bfd_elf_link_record_dynamic_symbol (stru
 	      && h->root.type != bfd_link_hash_undefweak)
 	    {
 	      h->forced_local = 1;
-	      return TRUE;
+	      if (!elf_hash_table (info)->keep_local_dynsyms)
+		return TRUE;
 	    }
 
 	default:
@@ -484,6 +485,6 @@ bfd_elf_record_link_assignment (bfd *out
   if ((h->def_dynamic
        || h->ref_dynamic
-       || info->shared)
+       || info->shared || elf_hash_table (info)->keep_local_dynsyms)
       && h->dynindx == -1)
     {
       if (! bfd_elf_link_record_dynamic_symbol (info, h))
@@ -667,7 +701,7 @@ _bfd_elf_link_renumber_dynsyms
 {
   unsigned long dynsymcount = 0;
 
-  if (info->shared)
+  if (info->shared || elf_hash_table (info)->keep_local_dynsyms)
     {
       const struct elf_backend_data *bed = get_elf_backend_data (output_bfd);
       asection *p;
@@ -8104,7 +8143,7 @@ bfd_elf_final_link (bfd *abfd, struct bf
       long last_local = 0;
 
       /* Write out the section symbols for the output sections.  */
-      if (info->shared)
+      if (info->shared || elf_hash_table (info)->keep_local_dynsyms)
 	{
 	  asection *s;