#1731: Assumption made about buffer header alignment
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Reporter: Paul C. Anagnostopoulos | Owner: Paul C. Anagnostopoulos
Type: bug | Status: assigned
Priority: normal | Milestone:
Component: core | Version: 2.6.0
Severity: low | Keywords:
Lang: | Patch:
Platform: |
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Comment(by doughera):
Replying to [comment:3 Paul C. Anagnostopoulos]:
> Sorry, confusing terminology. The buffer "header" is the information
stored in front of the actual buffer memory. The Buffer object is the
buffer "descriptor."
Ah, I see. Thanks for the new description. I had hoped that with the new
memory organization, that hidden flag stuck before _bufstart could have
been eliminated. I have never been a fan of that trick, and prefer to
tell the compiler explicitly what I'm doing so it automatically gets all
the alignment correct.
Does every Buffer have that Memory_Block element? If so, would it make
sense to just explicitly list it in the Buffer "descriptor?"
> Padding is only required if the
> alignment of the data portion is higher than that of a pointer.
> This was not the case as of 8/2010.
It depends on how the memory blocks are obtained and carved up. On 32-bit
SPARC, doubles should be aligned at 8-byte boundaries, but pointers are
only 4 bytes. I'm not sure how parrot obtains and carves up space for
those buffers.
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Ticket URL: <https://trac.parrot.org/parrot/ticket/1731#comment:4>
Parrot <https://trac.parrot.org/parrot/>
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