mach-o objfmt, amd64 relocation issues

[Henryk Richter]

Hi folks,

impatient as I am, I was unwilling to wait for the 0.7.0 milestone and  
started
a mach-o objfmt by myself. Please don't shoot me for the ugly code as  
I am not too
familiar with yasm's internals and possibly replicated redundant  
functionality.

I got basic 32 bit mach-o files working with text, data and bss  
sections. The
relocations still need some work, currently basic pointers, absolute  
symbols
and common vars seem to operate. Other relocations like WRT, PC-relative
and such are untested/inoperable.

My main problems, however start in 64 bit mode. So far I've got a  
simple test
application running which correctly interfaces with 64 bit code in  
certain conditions.
I can instruct the mach-o format to reloc 64 bit absolute addresses
(like in "mov rax,qword _somelabel"), calls are working but I need some
ideas to support such constructs as "mov rax,[_some_label]. The x86-64
implementation of mach-o seems to be heavily RIP-relative so that
"movq rax,[rip+_some_label" works but I cannot see how to assemble the
former symbol type (see attached reloc.h.gz). A reloc like  
"R_X86_64_32" as
present in ELF is not known to me.

Dynamic external symbols (like calling printf) would require quite a  
bit of
extra work and are not supported at this point.


regards,
Henryk



___________________________________________
Dr.-Ing. Henryk Richter

University of Rostock
Institute of Communications
R.-Wagner-Strasse 31
18119 Rostock, Germany

Phone:  +49 - 381 - 4987303
Mobile: +49 - 175 - 1771241
Fax:    +49 - 381 - 4987302
EMail:  henryk.richter at comlab.uni-rostock.de
URL:    http://horus.comlab.uni-rostock.de
___________________________________________



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