[llvm-dev] RFC: callee saved register verifier

[Sanjoy Das via llvm-dev]

Hi David,

David Blaikie wrote:
 > Yeah, that's sort of what I'd be wondering too.
 >
 > It seems like if the compiler does the right thing for existing calling
 > conventions - I hope our architecture is such that changing the set of
 > callee save registers reflects on both sides (both the caller - relying
 > on them to be saved, and the caller implementing that guarantee). So I
 > wouldn't expect making weird/random calling conventions to be likely to
 > have any new/interesting bugs here.

Yes, so far we've not had any issues with LLVM upholding its side of
the deal when it comes to calling conventions.  Humans tend to be
more prone to making mistakes, unfortunately.  :)

 >
 > But perhaps the architecture doesn't & can't work that way?

The intention is to add verification at call-sites that call into a
hand-written stub from LLVM generated code.

-- Sanjoy