> On Wed, 23 Mar 2011, Diego Novillo wrote: > > > Over at the PPH branch we are starting to re-use the LTO streaming > > routines to save front end trees. Clearly, there are things that need > > to be extended and/or replaced since LTO streaming assumes that we are > > in GIMPLE. However, there is a large intersection that I think can be > > commoned out. > > > > - ASTs do not need to concern themselves with language differences. > > They are generated and consumed by cc1plus, so saving > > language-dependent information is fine. > > - LTO streaming has several checks and assumptions that prevent > > non-gimple trees (e.g., DECL_SAVED_TREE must be NULL). > > > > I'm looking for opinions on what would be the best approach to factor > > out the common code. So far, I have created a layer of routines and > > data structures that the front end calls to manipulate PPH files. > > These are wrappers on top of LTO streaming that deal with all the > > sections, buffers and streams used by LTO. > > > > I was thinking of using langhooks to do things like checks (like the > > check for DECL_SAVED_TREE in > > lto_output_ts_decl_non_common_tree_pointers or the asserts in > > lto_get_common_nodes). I'm expecting that there will be other things, > > like handling more tree nodes in the tree streaming routines. But > > everything else seems to be already sufficiently flexible for our > > needs. > > > > Thoughts? > > Yes, Micha has a load of patches cleaning up streaming and removing > unecessary abstraction. So, why'd you need to share any of it? I
Cool, I also have some. > think it would be much easier if you worked with a copy (ugh, > streaming trees again....). I also think using same machinery for FE/gimple is a mistake. Trees are making life hard since they are interface in between FE<->gimplifier, part of gimple, interface for RTL expansion and way we represent debug info. Those are not neccesarily related things and tying them together makes things harder to optimize & cleanup. I would rather see well define Gimple bitcode rather than designing common format to handle PCHs, LTO and external templates on the top of existing trees. Honza > > Richard.
