For what it's worth, Android maintains an LLVM 3.2 bitcode writer (
I recently updated this to work with upstream LLVM @r209713. I know that
there are a few interested parties that would love to see this decoupled
and published as a separate library/utility, since there are now many
projects that chose ~3.2 as a relatively stable bitcode format.
Unfortunately, I never seem to have the time to be able to put it into a
separate form that would be suitable for other projects to use.
On Mon, Jun 2, 2014 at 7:37 AM, Tim Northover
> > I am wondering how to know the exhausted incompatibility of LLVM IR?
> Unfortunately, you're probably going to have a very hard time of it.
> Compatibility in that direction isn't something LLVM either tries to
> maintain or document. We try to make sure older bitcode files will
> compile with newer versions of LLVM, though even that only works to an
> The IR itself doesn't change *very* regularly (running "git log
> docs/LanguageReference.rst" would give some idea of what's happened
> since 3.2 -- I see ~150 since the 3.2 era). But how it's interpreted
> and what backends are expected to cope with is more in flux. And the
> API is almost certainly very different, so doing it all in a single
> process would lead to a world of pain.
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