gas on Mac OS X

[Martin Schaffner <schaffner at gmx dot li>]

Me and Aurelien Chanudet started porting GNU assembler to the 
powerpc-apple-darwin* target. It already parses the assembler output of 
a hello world C program, but can't yet generate Mach-O files.

I am currently stuck with design issues, and I don't know enough about 
BFD and assemblers in general to make competent decisions, so if you 
do, please speak up. I'll present the issues in the last part of this 
e-mail.

My copyright assignment has been accepted by the FSF.

All work we did up to now is here:
http://membres.lycos.fr/schaffner/prog/binutils/

Please review and apply the following:
----------------------------------
1) binutils-add-comments.ptch has nothing to do with darwin, it just 
adds some comments.
ChangeLog:
 2004-04-21 Martin Schaffner <schaffner@gmx.li>

 * gas/write.c, gas/config/tc-ppc.h: comment #endif with controlling 
macro

* binutils-darwin-add-reloc-types.patch adds relocation type 
definitions for mach-o. ChangeLog:
 2004-06-19 Martin Schaffner <schaffner@gmx.li>

 * bfd/bfd-in2.h, bfd/libbfd.h, bfd/reloc.c: define Mach-O-specific 
relocation types:
 BFD_RELOC_LO16_DS, BFD_RELOC_LO16_DS_BASEREL,
 BFD_RELOC_MACH_O_PAIR, BFD_RELOC_MACH_O_PB_LA_PTR, 
BFD_RELOC_MACH_O_JBSR

* binutils-darwin-parse.patch (depends on the previous) adds support 
for the assembler operators lo16(), hi16(), ha16(). ChangeLog:
 2004-04-21 Martin Schaffner <schaffner@gmx.li>

 * gas/config/tc-ppc.c: add support for Mach-O-specific assembly code


2) binutils-darwin-2004-6-19-safe.patch (to be applied after adding the 
files gas/config/obj-mach-o.{c,h}) contains darwin-related changes that 
should be "safe" to apply and should not influence other targets.
ChangeLog:
 2004-06-19 Martin Schaffner <schaffner@gmx.li>

 * gas/config/obj-mach-o.c, gas/config/obj-mach-o.h: new files for 
Mach-O support

 * gas/Makefile.in, gas/Makefile.am, gas/configure.in, 
gas/configure.am: add support for gas/config/obj-mach-o.{h,c}

 * bfd/mach-o.c: define MACH_O_MAGIC, move and rename macros for 
sections to bfd/mach-o.h

 * bfd/mach-o.h: add macros for mach-o sections


Future development
-----------------------
The rest of the patches is work in progress.
binutils-darwin-parse.patch enables gas to parse the hello world example
binutils-darwin-activate.patch tells the build system that darwin is a 
possible target - to be applied when everything else works
binutils-darwin-add-reloc-types.patch adds Mach-O-specific relocation 
types to BFD
binutils-darwin-2004-4-21.patch  is all patches from 2004-4-21 combined.
http://membres.lycos.fr/schaffner/prog/binutils/quoted_names.ptch adds 
(incorrect) support for quote-delimited identifers
mach-o-reloc.c is a file for the bfd directory, but I hope it finally 
won't be necessary.
cctools-495.tar.bz2 is a copy of apple's assembler source code
gas-apple.ptch is a diff between apple's assembler and gas-1.38, the 
version which apple forked to make their assembler

Design issues
--------------
Mach-O has two unique features: Indirect Symbols and Weak References. 
The proper way to support them is probably to add support to bfd. Can a 
BFD expert speak up on how to add this?

Here is the previous discussion, which ended because I hadn't completed 
my copyright assignment yet:
http://sources.redhat.com/ml/binutils/2004-04/msg00510.html
http://sources.redhat.com/ml/binutils/2004-04/msg00546.html

--
Martin Schaffner