Re: [Dwarf-Discuss] Fission + cross-CU references (ref_addr)

2017-05-05 Thread Robinson, Paul
I think it's pretty safe to say: -A reference into a TU from a CU or a different TU is invariably by ref_sig8, never by section offset. -A reference into a CU from another CU has to be by ref_addr; in a .o file this can use a relocation, in a .dwo file it has to be from inside t

Re: [Dwarf-Discuss] Fission + cross-CU references (ref_addr)

2017-05-05 Thread Robinson, Paul
I was mentioning this mostly by way of opportunistically suggesting "it might be a thing that would be good to think explicitly about, possibly allow, and design this new stuff around the possibility, perhaps". The entire point of a type unit is to allow size reduction by deduplication. Any kin

Re: [Dwarf-Discuss] Fission + cross-CU references (ref_addr)

2017-05-05 Thread David Blaikie
On Fri, May 5, 2017 at 11:14 AM Robinson, Paul wrote: > I was mentioning this mostly by way of opportunistically suggesting "it > might be a thing that would be good to think explicitly about, possibly > allow, and design this new stuff around the possibility, perhaps". > > The entire point of a

Re: [Dwarf-Discuss] Fission + cross-CU references (ref_addr)

2017-05-05 Thread Robinson, Paul
What guarantees that the information referred to is the same across all "duplicate" TUs or otherwise does not affect the semantic content of the TU? The same guarantees that exist without TU->CU references, I would think? It's up to the implementation to ensure that any two TUs are semantically

Re: [Dwarf-Discuss] Fission + cross-CU references (ref_addr)

2017-05-05 Thread David Blaikie
On Fri, May 5, 2017 at 11:50 AM Robinson, Paul wrote: > What guarantees that the information referred to is the same across all > "duplicate" TUs or otherwise does not affect the semantic content of the TU? > > The same guarantees that exist without TU->CU references, I would think? > It's up t