[Libunwind-devel] QNX support

[Fischer, Matt]

Hi all.  I'm interested in using libunwind on the QNX operating system, and 
started looking into what would be involved in doing that.  QNX has a number of 
stupidities^H^H^H^Hidiosyncrasies that I needed to deal with in order to get it 
building, like some nonstandard header locations, etc., but I think I have a 
set of changes put together that gets a very basic configuration up and 
building.  I'm attaching a patch that contains the work I've done so far, and I 
was wondering if I could get any comments on it.  It's a hodgepodge of 
different things, so I could split them up into pieces before actually 
submitting, if that would be better.

A quick summary:
* At the moment, I'm only interested in remote unwinding, so while I would like 
eventually add support for local unwinding on QNX, I can start out by simply 
disabling that.  Since currently the only time libunwind disables local 
unwinding is when it's building a cross-analyzer, I added a new configure 
switch (--(enable|disable)-local) which allows the user to explicitly disable 
local unwinding if desired.

* Similarly, ptrace support was being built unconditionally.  I added an 
--(enable|disable)-ptrace flag to allow explicit control over this, and set the 
default based on whether sys/ptrace.h exists.

* For some mysterious reason, QNX puts elf.h under sys/, so I added a bit of 
logic in libunwind_i.h to include it from that location when building on QNX.

* QNX also doesn't have <endian.h>, so the normal endianness logic will not 
work.  However, the compiler declares the macros 
__BIGENDIAN__/__LITTLEENDIAN__, so I added code to check those when building 
for QNX.

* Finally, the silly QNX compiler, qcc, doesn't understand the flag 
-nostartfiles unless you prefix it with -Wc, to pass it on to the underlying 
GCC compiler, so I added some logic to test for QCC and make the appropriate 
changes.

These changes are enough to get libunwind building if you pass --disable-local 
--disable-coredump during configure.  Support for the remaining pieces can 
probably be added later on as well, but I thought I would at least start the 
dialogue here by discussing these changes.  Are these modifications something 
that could be added to the project?  I'll be happy to tweak them if there are 
things I missed, or additional work you'd like to see done first.

Thanks,
Matt

________________________________

CONFIDENTIALITY NOTICE: This email and any attachments are for the sole use of 
the intended recipient(s) and contain information that may be confidential 
and/or legally privileged. If you have received this email in error, please 
notify the sender by reply email and delete the message. Any disclosure, 
copying, distribution or use of this communication (including attachments) by 
someone other than the intended recipient is prohibited. Thank you.

0001-Added-basic-QNX-support.patch
Description: 0001-Added-basic-QNX-support.patch