Re: Variable page size for ELF

[Ian Lance Taylor <ian@zembu.com>]

   Date: Sun, 11 Jul 1999 10:38:05 -0700 (PDT)
   From: hjl@lucon.org (H.J. Lu)

   > Merely changing the linker script is not a terribly useful feature,
   > since people can already change it anyhow.  The interesting new
   > feature here is changing the use of maxpagesize in the backend data
   > structure.  However, the only interesting use of the backend
   > maxpagesize is to set up the program headers, and you can already do
   > that using PHDRS in the linker script.

   I took a look at PHDRS. It is not easy to get it right with alignment
   by hand.

It's trivial to get the alignment right by hand in the SECTIONS
portion of the linker script.  Then there is no reason to worry about
the PHDRS part.

   > So I don't see any new functionality in the --page-size option.  Of
   > course, if it is a useful shorthand, we should add it anyhow.  But
   > that is where I wonder what the application is, since I don't see that
   > either.

   I got the request from our IA64 people.

Please do talk with Richard and/or me about just why they want this
option.  I am concerned that there is some misunderstanding at the
root of this request, and I would prefer to avoid adding a feature
which nobody will actually use.

   > By the way, MAXPAGESIZE should probably not be used as a symbol name
   > in a linker script, because it is part of the user's name space.
   > Something like __MAXPAGESIZE would be better.

   MAXPAGESIZE is a variable in linker script just like SIZEOF_HEADER.
   It shouldn't show up in executable.

I know.  However, using it in this way will prevent anybody from
referring to MAXPAGESIZE as a symbol in a linker script.  There are
other keywords in the linker script language with the same problem
(all those recognized in lexer state EXPRESSION).  I'm just showing a
somewhat belated concern for not adding another one, particularly
since MAXPAGESIZE is actually a vaguely plausible symbol name.

Ian