[PATCH] [RFC] Deprecated feature in TableGen

[Joey Gouly]

  > Hi Joey,
  >
  > With the multiple patches, I’m not completely clear on the state of things, so apologies if this is

  This is just me coding in the open, trying to get a good of how to approach this. I haven't spent a long time on these patches. I just found it easier to show in code.


  >I love the idea of being able to mark instructions (and aliases) as deprecated, but I’m not sure the mechanism of a custom comment handler is the right way to do it. We really want an assembler-time warning diagnostic when a deprecated instruction is used, for example. AFAICT, this implementation doesn’t support that and is tailored mainly for the disassembler use case, which quite honestly is much less interesting, IMO.

  The CustomComment approach was my second approach in trying to be more general (see the first approach as the first diff on this phabricator review)

  > That is, I’d like something more completely TableGen’erated rather than the hard-coded isDeprecated() function in the target’s asmparser class.

  So something generated into 'ARMGenAsmMatcher.inc' for example?

  Thanks for the comments, I hope we can push this forward!

http://llvm-reviews.chandlerc.com/D1399