PATCH: Add --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi] to ld

[H.J. Lu]

On Tue, Apr 14, 2015 at 5:55 PM, Alan Modra <amodra@gmail.com> wrote:
> On Mon, Apr 13, 2015 at 05:38:24AM -0700, H.J. Lu wrote:
>> On Sun, Apr 12, 2015 at 6:13 PM, Alan Modra <amodra@gmail.com> wrote:
>> > On Thu, Apr 09, 2015 at 03:07:20PM -0700, H.J. Lu wrote:
>> >> +  if (arg->link_info
>> >> +      && (arg->link_info->compress_debug & COMPRESS_DEBUG)
>> >> +      && arg->link_info->compress_debug != COMPRESS_DEBUG_GABI_ZLIB
>> >> +      && (asect->flags & SEC_DEBUGGING)
>> >> +      && name[1] == 'd'
>> >> +      && name[6] == '_')
>> >
>> > Here and in a couple of other places you omit checking the full prefix
>> > of the name.  Are you certain you won't see something like a ".de"
>> > section here?  It you might, then name[6] is a buffer overflow and a
>> > potential segfault.
>>
>> elf.c has
>>
>>   if ((flags & SEC_ALLOC) == 0)
>>     {
>>       /* The debugging sections appear to be recognized only by name,
>>          not any sort of flag.  Their SEC_ALLOC bits are cleared.  */
>
> OK, good.
>
>> Here is the completed patch.  OK for master?
>
> Would you mind looking at doing this a little cleaner?  The patch as
> it stands looks very much like a bolt-on.  I mean, you probably
> wouldn't write the code this way if elflink.c had compression in mind
> in the beginning..
>
> So, I'm wondering whether things would look better if
> elf_link_input_bfd allocated the extra buffer needed rather than in
> both _bfd_write_merged_section and _bfd_elf_set_section_contents.
> Of course, _bfd_write_merged_section would need two extra parameters,
> contents and offset, and write to "contents" if non-NULL rather than
> to the output file.

Thanks for the suggestion.  I allocated the buffer in bfd_elf_final_link
instead without adding extra arguments to _bfd_write_merged_section.
Here is the updated patch. OK for master?

-- 
H.J.
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