RFR(xs): 8145114: const-correctness for ucontext_t* reading functions

[Thomas Stüfe]

Hi David,

that was an oversight. see new webrev:

http://cr.openjdk.java.net/~stuefe/webrevs/8145114-const-correctness-ucontext/webrev.01/webrev/

and the delta to webrev 00:

http://cr.openjdk.java.net/~stuefe/webrevs/8145114-const-correctness-ucontext/webrev.00-01/

Thanks, Thomas

On Fri, Dec 11, 2015 at 11:21 AM, David Holmes <david.holmes at oracle.com>
wrote:

> Hi Thomas,
>
> In:
>
> ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
>                     intptr_t** ret_sp, intptr_t** ret_fp) {
>   ExtendedPC  epc;
>   ucontext_t* uc = (ucontext_t*)ucVoid;
>
>
> is there some reason these ucontext_t's were not made const?
>
> Thanks,
> David
>
> On 11/12/2015 7:57 PM, Thomas Stüfe wrote:
>
>> Hi David,
>>
>> On Fri, Dec 11, 2015 at 10:35 AM, David Holmes <david.holmes at oracle.com
>> <mailto:david.holmes at oracle.com>> wrote:
>>
>>     Hi Thomas,
>>
>>     This seems okay. To be honest I'm not sure of the usefulness but it
>>     certainly isn't harmful :)
>>
>>     I'll prepare similar changes to our internal platforms and run it
>>     all through JPRT.
>>
>>     Thanks,
>>     David
>>
>>
>>     On 11/12/2015 5:16 PM, Thomas Stüfe wrote:
>>
>>         Hi all,
>>
>>         please review this large-but-trivial change:
>>
>>         Bug: https://bugs.openjdk.java.net/browse/JDK-8145114
>>         webrev:
>>
>> http://cr.openjdk.java.net/~stuefe/webrevs/8145114-const-correctness-ucontext/webrev.00/webrev/index.html
>>
>>         Even though many files are involved, the changes are very
>>         trivial. The
>>         change takes care of declaring ucontext_t pointers as const for
>>         all utility
>>         functions which do not change the context (which are most of
>> them).
>>
>>         This fix was motivated by me wasting time in an error situation
>>         on AIX
>>         where I accidentally changed the register values in the context
>>         before
>>         printing them to the hs-err file.
>>
>>         And, like pulling a thread from a ball of yarn, the change got
>>         bigger and
>>         bigger... like it is once one starts to fix const issues. But
>>         the fixes in
>>         this case involve the bottom functions and should not force any
>>         new casts
>>         upon anyone.
>>
>>         I did build the change on the following platforms:
>>         AIX
>>         Linux x64 (with and without ZERO)
>>         Linux ppc
>>         OSX
>>         Solaris Sparc and x64
>>
>>         and all did build successfully.
>>
>>         Kind Regards, Thomas
>>
>>
>>