RFR: 8315431: ArchiveHeapWriter::get_filler_size_at() cannot handle buffer expansion

[Calvin Cheung]

On Tue, 23 Apr 2024 15:47:46 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> In `ArchiveHeapWriter::maybe_fill_gc_region_gap()`:
> 
> - The address of `filler` will change if the buffer (which is a GrowableArrayCHeap) expands.
> - Instead of storing the address, we store the offset of `filler` from the beginning of the buffer. This offset will not change even if the buffer expands.

Looks good.

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Marked as reviewed by ccheung (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18920#pullrequestreview-2049030891