RFR: 8264285: Clean the modification of ccstr JVM flags [v2]

[David Holmes]

On 1/04/2021 5:05 am, Ioi Lam wrote:
> On Wed, 31 Mar 2021 12:58:50 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:
> 
>>> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
>>>
>>>    relax flag attributions (ala JDK-7123237)
>>
>> src/hotspot/share/runtime/flags/debug_globals.hpp line 38:
>>
>>> 36: // have any MANAGEABLE flags of the ccstr type, but we really need to
>>> 37: // make sure the implementation is correct (in terms of memory allocation)
>>> 38: // just in case someone may add such a flag in the future.
>>
>> Could you have just added a develop flag to the manageable flags instead?
> 
> I had to use a `product` flag due to the following code, which should have been removed as part of [JDK-8243208](https://bugs.openjdk.java.net/browse/JDK-8243208), but I was afraid to do so because I didn't have a test case. I.e., all of our diagnostic/manageable/experimental flags were `product` flags.
> 
> With this PR, now I have a test case -- I changed `DummyManageableStringFlag` to a `notproduct` flag, and removed the following code. I am re-running tiers1-4 now.

Sorry but I don't understand how a test involving one flag replaces a 
chunk of code that validated every flag declaration ??

David
-----

> void JVMFlag::check_all_flag_declarations() {
>    for (JVMFlag* current = &flagTable[0]; current->_name != NULL; current++) {
>      int flags = static_cast<int>(current->_flags);
>      // Backwards compatibility. This will be relaxed/removed in JDK-7123237.
>      int mask = JVMFlag::KIND_DIAGNOSTIC | JVMFlag::KIND_MANAGEABLE | JVMFlag::KIND_EXPERIMENTAL;
>      if ((flags & mask) != 0) {
>        assert((flags & mask) == JVMFlag::KIND_DIAGNOSTIC ||
>               (flags & mask) == JVMFlag::KIND_MANAGEABLE ||
>               (flags & mask) == JVMFlag::KIND_EXPERIMENTAL,
>               "%s can be declared with at most one of "
>               "DIAGNOSTIC, MANAGEABLE or EXPERIMENTAL", current->_name);
>        assert((flags & KIND_NOT_PRODUCT) == 0 &&
>               (flags & KIND_DEVELOP) == 0,
>               "%s has an optional DIAGNOSTIC, MANAGEABLE or EXPERIMENTAL "
>               "attribute; it must be declared as a product flag", current->_name);
>      }
>    }
> }
> 
> -------------
> 
> PR: https://git.openjdk.java.net/jdk/pull/3254
>