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From: bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: Baby X is bor nagain
Date: Fri, 28 Jun 2024 11:15:36 +0100
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On 28/06/2024 00:58, Scott Lurndal wrote:
> bart <bc@freeuk.com> writes:
>> On 27/06/2024 21:23, Tim Rentsch wrote:
> 
>>> After taking care of all that the build did manage to produce an
>>> executable, which appears to have run successfully.
>>>
>>> After doing a trial run with the produced executable, I looked at
>>> the tcc man page.  As best I can tell, tcc simply silently
>>> ignores the -fPIC option.
>>
>> I think that it tries to be a drop-in replacement for gcc, so supports
>> some of its options, even if they don't do anything. Like -O3.
>>
>> Position-independent code seems to be a recent thing with gcc tools. My
>> tools didn't support it either, until a year ago when I found out about
>> ASLR.
> 
> gcc has supported generating position independent code for at
> over a quarter of a century.

I'm pretty sure that just 4 years ago, I was able to generate non-PIC 
object files that could be linked with gcc-ld on Windows.

When I tried it last year, it didn't work. So something changed, whether 
in compiler, or OS loader, where a dynamic image base address, which 
requires PIC, became the default.


>>
>> For most, PIC isn't a necessity.
> 
> That's your opinion. I don't think it matches reality.

The fact that it hasn't been needed, or been the default, for decades 
suggests that it isn't a necessity.

A 'necessity' isn't someone arbitrarily decreeing: 'all code must be PIC'.

If you took any Windows EXE and changed some flags in the headers, so 
loading at the given base address, it would probably still work.


> For most applications it doesn't matter and PIC code
> works just as well as PDC.

Hang on, isn't that what /I/ said, which you just disagreed with?