8065585: Change ShouldNotReachHere() to never return

[Kim Barrett]

On Apr 16, 2015, at 8:07 AM, Stefan Karlsson <stefan.karlsson at oracle.com> wrote:
> 
> I added a call to fatal(...) in the GC code. I get correct stacktraces in gdb, but the stacktraces in the hs_err files are broken with fastdebug and product builds:
> 
> Stack: [0x00007f12518d2000,0x00007f12519d3000], sp=0x00007f12519d0eb0,  free space=1019k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
> V  [libjvm.so+0x11db44a]  VMError::report_and_die()+0x1ba
> V  [libjvm.so+0x7efb80]  report_vm_error(char const*, int, char const*, char const*)+0x90
> V  [libjvm.so+0x7efc49]  report_vm_error_noreturn(char const*, int, char const*, char const*)+0x9
> V  [libjvm.so+0x7efc63]
> V  [libjvm.so+0xfd7937]
> V  [libjvm.so+0xfeec51]
> …
> 

I remember seeing an email thread recently asking about how gdb produced stack traces, because
it was successful in some cases where our mechanisms for producing hs_err files was not.  So there
might already be a bug about it.

But that does seem like it makes this whole proposal not work until that problem is fixed.