RFR [S] 8081406: cleanup and minor extensions of the debugging facilities in CodeStrings

[Bertrand Delsart]

Friendly reminder.

Bertrand.

On 28/05/2015 19:02, Bertrand Delsart wrote:
> Hi all,
>
> Small RFR to address minor issues in debug mode with CodeStrings
>
> https://bugs.openjdk.java.net/browse/JDK-8081406
> http://cr.openjdk.java.net/~bdelsart/8081406/webrev.00/
>
> The change does not impact the product mode.
>
> In non product mode, CodeStrings allows to associate a linked list of
> strings to a CodeBuffer, CodeBlob or Stub. In addition, with ASSERTS, it
> defines a boolean asserting whether the list of strings are valid.
>
> Here are the issues addressed by this CR:
>
> - The old code mentioned the fact that CodeStrings was not always
> correctly initialized. This is addressed by the fix, allowing
> check_valid to be added at a few locations where it could currently
> failed due to uninitialized values (like at the beginning of
> CodeStrings::free). This also makes the code more robust against future
> versions of CodeStrings.
>
> - As a minor extension, it is now possible for platform dependent code
> to modify the comment separator used by print_block_comment, which was
> hard coded to " ;; ".
>
> - As another minor extension, related to the validity assertions,
> freeing a code string no longer necessarily marks it (and hence its
> Stub/CodeBlob/CodeBuffer) as invalid. If CodeStrings contains only
> comment, removing them does not change the validity of the CodeStrings.
> For similar reason, assignment over a non null CodeStrings is now valid
> when we can safely free the old string.
>
> The modified code passes JPRT. It was also validated in fastdebug mode
> with the vm.compiler.testlist to check that the validity assertion were
> not triggered. One of our closed extensions also validated advanced use
> of CodeStrings::assign (included cases where the target of the
> assignment was not free).
>
> Best regards,
>
> Bertrand.
>


-- 
Bertrand Delsart,                     Grenoble Engineering Center
Oracle,         180 av. de l'Europe,          ZIRST de Montbonnot
38330 Montbonnot Saint Martin,                             FRANCE
bertrand.delsart at oracle.com             Phone : +33 4 76 18 81 23

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