2014-07-24 17:41 GMT+04:00 Jan Hubicka <hubi...@ucw.cz>: >> > So the patch is introducing yet another notion of clone (in addition to >> > existing virtual clones >> > and function versions used by ifun) and you add a new type of reference >> > (CHKP) to link the >> > original and the clone. >> > >> > Why do you need to link things in 3 different ways? (i.e. >> > instrumented_version points to the >> > same place as CHKP and as orig_decl, right?). >> >> CHKP reference is required to have reachability algorithms working >> correctly and not removing required instrumented nodes. References >> are rebuilt time to time and instrumented_version is used to rebuild >> CHKP reference. orig_decl is required because original function node >> may be removed as unreachable. >> >> > >> > I would preffer if this can be put into the existing clone mechanizm. The >> > virtual clones can >> > have quite generic transformations done on them and the do perform all the >> > necessary links >> > back and forth. >> >> I suppose virtual clones are useful when we may delay their >> materialization, i.e. for IPA passes. For checker we have >> instrumentation almost immediately following clone creation. >> Instrumentation is a GIMPLE pass and we have to materialize clones to >> have bodies to instrument. After materialization there is no link to >> original node anymore and it means we would still require all new >> fields in cgraph_node structure. >> >> > >> > I will look into the rest of changes, is there some overview? >> >> I have a short overview of how it works on a wiki page: >> https://gcc.gnu.org/wiki/Intel%20MPX%20support%20in%20the%20GCC%20compiler#Instrumentation_clones > > Thanks, I will take a deeper look. I am just somewhat concerned that you seem > to be duplicating a lot of logic that is already present in the other clonning > schemes we have (i.e. arranging sane partitining, keeping clones linked with > their original etc). We may want to generalize current mechanizm rather than > implementing similar in parallel...
Thanks for looking into this! I looked into clones mechanism before introducing instrumentation clones and did not see how I can re-use it. Probably you may see if it can be easily adopted. Thanks, Ilya > > Sorry for ignoring the patches so long - I seem to have missed my CC in > original > thread. I would welcome if you CC hubi...@ucw.cz for cgraph/ipa related > patches. > > Honza >
