[PATCH] - objcopy --extract-symbol clears e_flags ELF header field

[Ronald Hoogenboom]

On 10/14/2015 02:21 AM, Alan Modra wrote:
> On Tue, Oct 13, 2015 at 07:51:56PM +0200, Ronald Hoogenboom wrote:
>> @@ -2624,11 +2623,13 @@
>>      finalization work for private section headers.  Do that here.  */
>>   
>>   static void
>> -setup_bfd_headers (bfd *ibfd, bfd *obfd)
>> +setup_bfd_headers (bfd *ibfd, bfd *obfd, int data)
>>   {
>>     /* Allow the BFD backend to copy any private data it understands
>>        from the input section to the output section.  */
>> -  if (! bfd_copy_private_header_data (ibfd, obfd))
>> +
>> +  if (! (data?bfd_copy_private_header_data (ibfd, obfd):
>> +		  bfd_copy_private_bfd_data(ibfd, obfd)))
>>       {
>>         status = 1;
>>         bfd_nonfatal_message (NULL, ibfd, NULL,
> I'll guess that you haven't tested this on targets other than ARM ELF,
> and when/if you do you'll find that it regresses other targets.  For
> binutils changes like this I test on a large number of targets to get
> some coverage for the various machine and object format combinations.
Indeed I was short-sighted and only cared about the broken 
--extract-symbol on ARM-elf. I saw in the bfd-elf32-arm that this 
function copied the EABI. I was hoping BFD would just do 'the right 
thing' for others too.
> One complication in this case is that the existing --extract-symbol
> test is in ld/testsuite/ld-elf/ meaning that it only runs for ELF
> targets, which is stupid.  So you'd need to write a test to live in
> binutils/testsuite/binutils-all/ or run tests by hand.
>
> I suspect the correct patch is to delete these lines in objcopy.c
> copy_object
>
>    /* Do not copy backend data if --extract-symbol is passed; anything
>       that needs to look at the section contents will fail.  */
>    if (extract_symbol)
>      return TRUE;
>
> and deal with the fallout in all the target bfd_copy_private_bfd_data
> functions.
>
Or move the 2 lines to after the bfd_copy_private_bfd_data. So BFD needs 
to be adapted for all kinds of targets I never even heard about. There 
the test in the testsuite will be indispensable. Can you give me some 
pointers on how to get that done?