RFR: 8263709: Cleanup THREAD/TRAPS/CHECK usage in JRT_ENTRY routines [v2]

[Harold Seigel]

On Thu, 8 Apr 2021 09:25:48 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> The existing JRT_ENTRY (and related) macros require the function to which they are applied to declare a parameter "JavaThread* thread" which represents the current thread. These functions are all implicitly "traps" functions as they can result in exceptions, but they are not declared with TRAPS because the only caller of these functions is the runtime itself (via call_VM) and no callers need to be aware to use CHECK; further they need a JavaThread. So the macro declares the THREAD variable for use with other exception-producing functions and assigns it from "thread".
>> 
>> The majority of this change replaces the parameter name "thread" with "current" so that it is clear that we are always dealing with the current thread. This affects the entry functions as well as the functions called therefrom.
>> 
>> We can then also replace the use of "THREAD" with "current", in contexts that are not related to exception processing.
>> 
>> Some methods called by entry functions were declared to have both a "thread" parameter and a "TRAPS" parameter - with nothing to tell you these are always the same, current, thread. So the "thread" parameter is removed and replaced with a local variable "current" obtained from THREAD->as_Java_thread().
>> 
>> Some missing CHECK_ uses were added.
>> 
>> Testing:
>>   - tiers 1-3
>> 
>> Thanks,
>> David
>
> David Holmes has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed CHECK on return statement.

src/hotspot/share/interpreter/interpreterRuntime.cpp line 303:

> 301:   // We'd expect to assert that we're only here to quicken bytecodes, but in a multithreaded
> 302:   // program we might have seen an unquick'd bytecode in the interpreter but have another
> 303:   // current quicken the bytecode before we get here.

This should still say 'thread', not 'current'

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PR: https://git.openjdk.java.net/jdk/pull/3394