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Dubious manual unwind annotations for ARMv7 assembly-language functions
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Authored by rwatson on Oct 4 2015, 11:13 AM.



Add additional hand annotations to various bcopy() variations in the "xscale" version of the ARMv7 memory copying code. Labelled as dubious because these functions don't obey normal conventions for stack use / block structure, and so some of the annotations may behave less well than desirable. However, overall, stack traces in this code are markedly improved.

NB: Not for this change, but .. all of the memory copying code in/around ARMv[67] seems a bit broken. We should replace them all with the ARM-provided reference implementations which are likely faster and better in every way.

Test Plan

Deployed in Cambridge L41 2014-2015.

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rwatson retitled this revision from to Dubious manual unwind annotations for ARMv7 assembly-language functions.
rwatson updated this object.
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rwatson added reviewers: andrew, bz, br.
rwatson set the repository for this revision to rS FreeBSD src repository - subversion.
rwatson added a project: ARM.

I'm not sure if this will work, I think the unwind instructions are per-function, but would need to see what clang generates to know for sure.