RFR (S) 8217994: os::print_hex_dump should be more resilient against unreadable memory

[zgu at redhat.com]

Looks good to me.

But you may need "default" switch to make some compilers happy.

Thanks,

-Zhengyu

On Tue, 2019-01-29 at 17:54 +0100, Aleksey Shipilev wrote:
> RFE:
>   https://bugs.openjdk.java.net/browse/JDK-8217994
> 
> Fix:
>   http://cr.openjdk.java.net/~shade/8217994/webrev.01/
> 
> This is related to JDK-8217879 (hs_err should print more instructions
> in hex dump), and this more
> generic fix should cover more cases in error handler. New gtest
> verifies we can call os::p_h_d on
> bad memory now. It also implicitly verifies that SafeFetch machinery
> works fine. Consider running
> that gtest (make images run-test TEST=gtest:os) on your platform if
> you suspect it does not.
> 
> Testing: (Linux, Windows) x86_64 build, gtest, eyeballing gtest
> output
> 
> Thanks,
> -Aleksey
>