RFR: 8360522: G1: Flag constraint functions for G1SATBBufferSize and G1UpdateBufferSize are skipped during argument validation

[Albert Mingkun Yang]

On Wed, 25 Jun 2025 12:53:03 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

> Hi,
> 
> Please review this change to move constraint function execution for  G1SATBBufferSize and G1UpdateBufferSize  to AfterErgo. These functions rely on the UseG1GC flag to determine whether to apply checks. However, during the AtParse phase of argument handling, UseG1GC may not yet be processed, which causes the constraints to be skipped.
> 
> Testing:
> `java -XX:G1SATBBufferSize=0 -version`
> `G1SATBBufferSize (0) must be in range [1, 4294967295]`
> `Error: Could not create the Java Virtual Machine.`
> `Error: A fatal exception has occurred. Program will exit.`

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/25979#pullrequestreview-2958373343