RFR: 8342870: Errors related to unused code on Windows after 8339120 in accessibility [v5]

[Alexander Zuev]

On Tue, 7 Jan 2025 09:56:11 GMT, Julian Waters <jwaters at openjdk.org> wrote:

>> After 8339120, gcc began catching many different instances of unused code in the Windows specific codebase. Some of these seem to be bugs. I've taken the effort to mark out all the relevant globals and locals that trigger the unused warnings and addressed all of them by commenting out the code as appropriate. I am confident that in many cases this simplistic approach of commenting out code does not fix the underlying issue, and the warning actually found a bug that should be fixed. In these instances, I will be aiming to fix these bugs with help from reviewers, so I recommend anyone reviewing who knows more about the code than I do to see whether there is indeed a bug that needs fixing in a different way than what I did
>> 
>> build.log on release configuration:
>> 
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp: In function 'int regEnable()':
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:334:14: warning: unused variable 'freeData' [-Wunused-variable]
>>   334 |         bool freeData = false;
>>       |              ^~~~~~~~
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:326:11: warning: unused variable 'retval' [-Wunused-variable]
>>   326 |     DWORD retval = -1;
>>       |           ^~~~~~
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp: In function 'int regDeleteValue(HKEY, LPCWSTR)':
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:379:14: warning: unused variable 'freeData' [-Wunused-variable]
>>   379 |         bool freeData = false;
>>       |              ^~~~~~~~
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:367:11: warning: unused variable 'retval' [-Wunused-variable]
>>   367 |     DWORD retval = -1;
>>       |           ^~~~~~
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/bridge/AccessBridgeCalls.c: In function 'shutdownAccessBridge':
>> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win3...
>
> Julian Waters has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:
> 
>  - Merge branch 'openjdk:master' into accessibility
>  - Cast to void in AccessBridgeCalls.c
>  - static_cast to void in jaccessinspector.cpp
>  - Formatting changes in AccessBridgeEventHandler.cpp
>  - Merge branch 'master' into accessibility
>  - Remove now unused result
>  - Merge branch 'master' into accessibility
>  - 8342870

src/jdk.accessibility/windows/native/bridge/AccessBridgeCalls.c line 233:

> 231:             return TRUE;
> 232:         }
> 233:         ((void) error);

Not sure why do we need it. I mean there is a value assignment before so why would compiler complain?

src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp line 326:

> 324: int regEnable() {
> 325:     HKEY hKey;
> 326:  // DWORD retval = -1;

I don't think we need to comment out both retval and freeData. It is either remnants of the code that was long gone or (more likely) were just a copy of another template method that actually uses these variables. If variables are not used within the function i would just delete them.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21656#discussion_r1922905467
PR Review Comment: https://git.openjdk.org/jdk/pull/21656#discussion_r1922905577