Hi, in order to implement all sorts of IPA-devirtualization in WHOPR, I need to store type of OBJ_TYPE_REF_OBJECT when streaming a call graph edge. I assume that lto_output_tree and lto_input_tree are what I need to use. Unfortunately, I have not been really able to use neither.
The problem with lto_output_tree is that it requires a parameter of type output_block whereas lto_output_edge only has lto_simple_output_block at its disposal. Do I understand it correctly that this is basically a different thing and that I need to change all output functions to use the former? Is there any downside to it or a pitfall that I should be aware of? Does it require any change on the reader's side? I also have a problem with the parameters of lto_input_tree. This time the required lto_input_block is available but it also requires something of the type struct data_in. I have tried to mimic the code in ipa-prop.c (which is a bit awkward and probably easy to get wrong) to get one but my first attempt ended in rather non-obvious segfaults. Yes, it could not have worked because I did not solve the previous problem but segfaulted when I tried to set the reader up, before any actual reading, so I guess I got something else wrong here too. What would be the easiest way to get a required data_in? I understand it is my very limited understanding of the underling concepts of the streaming code that results into these kinds of problems. Is there something I could read to improve my knowledge in this area? Thanks a lot in advance, Martin
