[PATCH] D19236: Add DITypeIndex for CodeView and emit it for locals

[Amjad Aboud via llvm-commits]

aaboud added a comment.

Hi Reid,
Thanks for the answers, now as I understand more your plan, I have more questions:

1. You want to use indices into list of MDString per CU to improve LTO linkage and reduce type footprint by improving merging types from different compile unites. right? 1.a. I claim that we can achieve that by doing a deep compare on current debug info metadata (based DWARF), do you agree?
2. Regarding the MDString, it should be generated canonically, otherwise the compare will fail, right? 2.a. Can you give example on what it will contain for class types? 2.b. I claim that we can generate that MDString today by traveling on "DI*Type" entries (based dwarf), do you agree or you think that we already lost some information? 2.c. I assume you will still need to generate "DI*Type" entries for compound types (maybe with the index into the MDString list), as you cannot get all information from the MDString, can you? 2.d. Do you have estimation on how much size the "llvm.dbg.cvtypes" will consume? Can you assure we will end up reducing the IR size and not increasing it?
3. If the idea is to reduce the size of the LTO IR, why we are not doing this also for DWARF, why just for CV types?

Thanks,
Amjad


http://reviews.llvm.org/D19236