Re: c/2678: gcc/g++ should stick compilation options into the .o file

["Ronald F. Guilmette" <rfg@monkeys.com>]

The following reply was made to PR c/2678; it has been noted by GNATS.

From: "Ronald F. Guilmette" <rfg@monkeys.com>
To: Phil Edwards <pedwards@disaster.jaj.com>
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: c/2678: gcc/g++ should stick compilation options into the .o file 
Date: Sun, 29 Apr 2001 11:47:39 -0700

 In message <20010429055624.A28542@disaster.jaj.com>, you wrote:
 
 >On Sat, Apr 28, 2001 at 08:36:49PM -0000, rfg@monkeys.com wrote:
 >> And I don't think that it would
 >> be very hard to get the front-end gcc/g++ driver to pass
 >> ALL compilation options down to cc1 and/or cc1plus.
 >
 >We already do...
 
 How convenient!
 
 >> They
 >> in turn could easily still the options into a suitable ELF
 >> section.
 >
 >I can't see any obvious documentation of .note sections in the gas source,
 >and I don't see .command mentioned at all.  I wouldn't mind playing with this
 >idea while waiting on compiles, if you can point me towards some usage docs.
 
 My alopogies if my slippery fingers typed in `.command' when I intended
 to write `.comment'.
 
 For documentation of the intended usage and format of data in ELF .note
 and .comment sections, you will need to refer to the original AT&T docu-
 mentation of ELF.  I know that documentation (in various non-modified
 and slightly modified forms) is available on the web in various places,
 because I found it on the web in several places when I went looking for
 it a couple of months ago.
 
 I'll find a URL or two for you if you need them.  Just let me know.
 
 Stuff that is placed into ELF .note sections is supposed to obey a very
 well defined format.  However stuff in .comment sections is more in the
 nature of just free-form text lines, I believe.  I can't remember anymore.
 
 What gets put into a .note section is basically 100% implementation defined,
 but when I glanced again at the original AT&T documentation on ELF the other
 day, it appears to me that the contents of .note is supposed to be, in
 effect, a set of name/value pairs (vaguely reminicent of UNIX environment
 variables).  The required ``structure'' of the .note section just tells
 you where and how to encode one of these name/value pairs, in general.