[PATCH] Use ELF_SECTION_IN_SEGMENT to map segments

Alan Hayward Alan.Hayward@arm.com
Wed May 23 12:04:00 GMT 2018


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.




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