[PATCH] Use ELF_SECTION_IN_SEGMENT to map segments

[Alan Hayward]

Pushed this with changes as suggested.

The BFD patch hasn’t progressed yet (possible extra changes needed
elsewhere). Regardless, this patch can stand on it’s own.

Alan.

> On 23 May 2018, at 11:36, Alan Hayward <Alan.Hayward@arm.com> wrote:
> 
> 
> Thanks for the review.
> 
>> On 22 May 2018, at 14:46, Pedro Alves <palves@redhat.com> wrote:
>> 
>> On 05/22/2018 12:00 PM, Alan Hayward wrote:
>>> The macro ELF_SECTION_IN_SEGMENT should be used when calculating if
>>> a section maps to a segment.
>>> 
>>> The binutils patch "[PATCH] Use offsets instead of addresses in
>>> ELF_SECTION_IN_SEGMENT" makes further improvements to the macro.
>>> When the two patches are combined, this will allow GDB to be used
>>> to debug Arm baremetal binaries produced by the Arm Compiler. See
>>> the binutils patch for further details.
>>> 
>>> Regardless of Arm debugging, this patch reduces code/logic duplication
>>> in gdb.
>> 
>> Sounds reasonable.
>> 
>>> --- a/gdb/elfread.c
>>> +++ b/gdb/elfread.c
>>> @@ -120,17 +120,13 @@ elf_symfile_segments (bfd *abfd)
>>>  for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
>>>    {
>>>      int j;
>>> -      CORE_ADDR vma;
>>> +      Elf_Internal_Shdr *this_hdr = &(elf_section_data (sect)->this_hdr);
>> 
>> Drop unnecessary parens.  
>> 
>> You could defer this call until after the SEC_ALLOC check.
> 
> Ok.
> 
>> 
>>> 
>>>      if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
>>> 	continue;
>>> 
>>> -      vma = bfd_get_section_vma (abfd, sect);
>>> -
>>>      for (j = 0; j < num_segments; j++)
>>> -	if (segments[j]->p_memsz > 0
>>> -	    && vma >= segments[j]->p_vaddr
>>> -	    && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
>>> +	if ELF_SECTION_IN_SEGMENT (this_hdr, segments[j])
>> 
>> That is some odd-looking C/C++ code, for assuming the macro's
>> internals are wrapped in parens.  Please write the more usual:
>> 
>> 	if (ELF_SECTION_IN_SEGMENT (this_hdr, segments[j]))
> 
> Not quite sure why I didn’t spot that when writing it.
> 
> 
>> 
>> OK with those fixed.
>> 
> 
> I’ll wait until the BFD patch has been approved before I push, as there
> is a small chance that review will cause me to make further changes. Will
> post again if I do.
> 
> 
> Alan.