[compiler-rt][XRay] Address follow-up comments to initial interface and…

Authored by dberris on Jul 29 2016, 12:11 AM.


[compiler-rt][XRay] Address follow-up comments to initial interface and initialisation code

This addresses some comments from D21612, which contains the following changes:

  • Update xray_patch() and xray_unpatch() API documentation to not imply asynchrony.
  • Introduce a scope cleanup mechanism to make sure we can roll-back changes to the XRayPatching global atomic.
  • Introduce a few more comments for potential extension points for other platforms (for the implementation details of patching and un-patching).

Reviewers: eugenis, rnk, kcc, echristo, majnemer

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D22911

llvm-svn: 277124