On 17.12.2012 21:22, Rich Felker wrote:
> On Mon, Dec 17, 2012 at 11:58:29AM -0500, Rich Felker wrote:
> To track this down, you could run under gdb and just interrupt the
> program and look at a backtrace once it hangs. This should make it
> clear whether exit was called recursively.
>
> Rich
>

Looks something like that (gdb output in the attached file, `bt` while 
`opt` hangs in the bottom): I've set `break exit` and stepped till it 
hangs, first exit() happens in command line parsing 
(https://github.com/llvm-mirror/llvm/blob/master/lib/Support/CommandLine.cpp#L846), 
which calls report_fatal_error("IO failure on output stream.");, which 
calls exit itself.

Looks like (note that I'm barely know C/C++) something wrong in ostream 
destruction: after changing ifdef to ifndef @
https://github.com/llvm-mirror/llvm/blob/master/lib/Support/raw_ostream.cpp#L501 
all works as it should:
> ~ # /root/llvm-build/Release+Asserts/bin/opt --reject-this-option 2>&-
> ~ # echo $?
> 1

//wbr ojab