Re: [non-GCC] Writing a compiler-backend for Linux/PowerPC

["Joseph S. Myers" <jsm at polyomino dot org dot uk>]

On Thu, 30 Sep 2004, Suriya Narayanan M S wrote:

> Could someone point me to some (authoritative) documents on writing a
> compiler/backend for Linux on PowerPC. I have the ISA manual. But I would
> like to have some information about the ABI for Linux (does Linux follow
> the System V ABI ?).
> 
> I had a look at [1], but it would be good if someone could specify with
> certainty, what I need to look at.
> 
>   1. http://gcc.gnu.org/readings.html

Although GCC cannot officially cooperate with the LSB 
<http://gcc.gnu.org/ml/gcc/2004-08/msg00003.html>, the specifications (see 
www.linuxbase.org) are still useful as far as they go as descriptions of 
the de facto ABIs on various platforms.  For example, there are LSB 1.3 
for PPC32 and LSB 2.0 for PPC64, with references to SysV ABI documents and 
descriptions of some aspects of the ABI beyond those documents.

It would be good for the GCC manual to have a section of statements of the 
form "on platform X, with default options, GCC follows the ABI in document 
Y with extensions and exceptions Z" (and the documentation of 
ABI-affecting command-line options should make clear how they affect the 
ABI).  Contributions of such documentation are welcome.  In some cases we 
do have web pages describing the GCC ABI on particular platforms where 
there isn't an underlying standard ABI document; for example, for H8/300.

Contributions to the testsuite in gcc.dg/compat, which can be used to test 
ABI compatibility between GCC and other compilers (including the same or 
other versions of GCC) are also useful.

-- 
Joseph S. Myers               http://www.srcf.ucam.org/~jsm28/gcc/
  http://www.srcf.ucam.org/~jsm28/gcc/#c90status - status of C90 for GCC 4.0
    jsm@polyomino.org.uk (personal mail)
    jsm28@gcc.gnu.org (Bugzilla assignments and CCs)