Getting function parameters from LLIL_CALL / LLIL_SYSCALL

[crand6]

I notice that LLIL_CALL only has a dest operand, while the LLIL_CALL_SSA includes addition info such as output, stack, and param. This extra information seems to me like it should have come from the calling convention. To help my understanding:

1. Why is this information tied into the SSA form? I originally anticipated I would get information like that from one of the bv.arch.calling_conventions.
2. Is just getting the LowLevelILInstruction.ssa_form sufficient to then get what registers/stack addresses would be used to pass arguments? Or would I be missing additional information by not doing an analysis on an entire LowLevelILFunction? (In my case, I just want to know what registers are used generally (the calling convention), not the actual possible value of an SSA variable).
3. What are the pros/cons of providing this information through SSA form instead of something like a "calling convention" operand?

[plafosse]

That information is generated from SSA, its doesn't exist in LLIL (non-ssa) because we haven't generated that information yet. It sounds like MLIL will be a better bet for doing the type of analysis that you're trying to do.