Re: [RFC PATCH v6 0/2] Make eBPF programs output data to perf

[Alexei Starovoitov <ast@plumgrid.com>]

On 8/13/15 2:35 PM, pi3orama wrote:
> I was thinking about whether to add a "type" field there, so we will have an explicit
> mov const instruction before the call instruction, which can act as a mark. Also, if
> we generate the type code automatically, a type field in this API can make things
> easier since we don't need wrap the user structure in BPF stack. However, the
> LLVM side is not ready yet, so we haven't post the new version.

I think the helper was clean enough. Any type info probably needs to be
done as a side channel and not part of the helper anyway.
But, ok, let's figure out the type stuff first.
Also I don't think you can rely on extra insn in front of a call insn.
Compiler can freely insert other insns there. You don't want to
introduce data flow analysis in elf parser.