Default entry point for ELF shared objects

[Paul Koning]

> On Sep 16, 2021, at 11:14 AM, Hans-Peter Nilsson <hp@bitrange.com> wrote:
> 
> On Thu, 16 Sep 2021, Florian Weimer via Binutils wrote:
> 
>> * Fangrui Song:
>> 
>>> ...
>>> This behavior is documented at https://sourceware.org/binutils/docs/ld/Entry-Point.html
>>> 
>>> "the address of the first byte of the ?.text? section, if present;"
>>> 
>>> The rule is quite ad-hoc and I'd support the removal.
>> 
>> I saw that.  I still wonder where it came from originally.  It seems
>> more like something for a bare-metal target.  Maybe it can be kept for
>> those,
> 
> Even if so, IMHO it should be updated to be "the text segment"
> or words to that effect, as the .text *section* is likely just
> main code located after .startup or .init or similar.

A default entry point really doesn't make any sense for any target, bare metal or otherwise.  Yes, it's possible such a random guess is the right answer some of the time, but clearly any build can always supply an explicit start address -- and in my view that should be required.

As an example, the DEC object format has a special code point meaning "no start address", and that is the default.

	paul