Re: arm-*-*-ld --oformat binary SEGMENTATION FAULT

[Nick Clifton]

Hi Marco,

> I have encountered a problem linking a binary format executable with 
> target ARM. No matter whatever I link, when I use --oformat binary the 
> result is always the same: segmentation fault.

  It is a known problem for the ARM port of the linker that you cannot 
convert to the binary format at the same time as performing a final 
link.  You have to link to the default output format first and then use 
objcopy to convert the resulting executable into the binary file format.

There is a check in the ARM portion of the linker's source code which 
detects when the output format is changed and issues an error message, 
but unfortunately this test was being performed too late.  I will be 
applying the attached patch to fix this.  With the patch applied I now 
get this output when running your test case:

  % arm-angstrom-linux-gnueabi-ld -o source.bin --oformat binary
source.o
  error: Cannot change output format whilst linking ARM binaries.

Cheers
  Nick

ld/ChangeLog
2008-10-22  Nick Clifton  <address@hidden>

        * emultempl/armelf.em (arm_elf_after_open): Move check for using a
        non-arm output target from here...
        (arm_elf_create_output_section_statements): ... to here, so that
        the check is made at the earliest possible opportunity.

Index: ld/emultempl/armelf.em
===================================================================
RCS file: /cvs/src/src/ld/emultempl/armelf.em,v
retrieving revision 1.67
diff -c -3 -p -r1.67 armelf.em
*** ld/emultempl/armelf.em      21 Oct 2008 22:20:29 -0000      1.67
--- ld/emultempl/armelf.em      22 Oct 2008 14:21:21 -0000
*************** gld${EMULATION_NAME}_before_parse (void)
*** 55,70 ****
  static void
  arm_elf_after_open (void)
  {
-   if (strstr (bfd_get_target (link_info.output_bfd), "arm") == NULL)
-     {
-       /* The arm backend needs special fields in the output hash structure.
-        These will only be created if the output format is an arm format,
-        hence we do not support linking and changing output formats at the
-        same time.  Use a link followed by objcopy to change output formats.  
*/
-       einfo ("%F%X%P: error: cannot change output format whilst linking ARM 
binaries\n");
-       return;
-     }
- 
    {
      LANG_FOR_EACH_INPUT_STATEMENT (is)
        {
--- 55,60 ----
*************** gld${EMULATION_NAME}_finish (void)
*** 439,444 ****
--- 429,444 ----
  static void
  arm_elf_create_output_section_statements (void)
  {
+   if (strstr (bfd_get_target (link_info.output_bfd), "arm") == NULL)
+     {
+       /* The arm backend needs special fields in the output hash structure.
+        These will only be created if the output format is an arm format,
+        hence we do not support linking and changing output formats at the
+        same time.  Use a link followed by objcopy to change output formats.  
*/
+       einfo ("%F%X%P: error: Cannot change output format whilst linking ARM 
binaries.\n");
+       return;
+     }
+ 
    bfd_elf32_arm_set_target_relocs (link_info.output_bfd, &link_info,
                                   target1_is_rel,
                                   target2_type, fix_v4bx, use_blx,