Peng Yu via llvm-dev
2019-Jan-25 18:51 UTC
[llvm-dev] Compatibility of .ll file among different versions of LLVM
Hi, I am wondering what is the compatibility of .ll file. For example, for a .ll file generated by an older version of LLVM, can it be guaranteed to be assembled to a bc file using a newer version of LLVM and run correctly? Thanks. -- Regards, Peng
Tim Northover via llvm-dev
2019-Jan-25 19:07 UTC
[llvm-dev] Compatibility of .ll file among different versions of LLVM
On Fri, 25 Jan 2019 at 18:52, Peng Yu via llvm-dev <llvm-dev at lists.llvm.org> wrote:> I am wondering what is the compatibility of .ll file. For example, for > a .ll file generated by an older version of LLVM, can it be guaranteed > to be assembled to a bc file using a newer version of LLVM and run > correctly? Thanks.The policy is documented here: https://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility Basically, .ll files have no guarantees at all: you must assemble them with the same compiler that generated them. Newer LLVMs can read .bc files from 3.0 onwards (if not, report a bug), but we reserve the right to break compatibility at some point in the future (giving sufficient warnings etc). Cheers. Tim.