swift234

Debug Info: Use the AST instead of SIL to determine the argument ordering.
The old SIL-based approach failed to recognize function arguments of
SIL-inlined functions as arguments.

Post-Xcode 7 it would be better to lower this information during SILGen
and emit a debug_value for every function argument so we don't need
to reconstruct them after all the SIL optimizations.

rdar://problem/21109015

Swift SVN r29180