Hi LLDB team,

as part of the ABI work for this year we would like to adopt the swift calling 

I am working on the swift/llvm side of this.

<rdar://problem/19978563> Adopt the new Swift calling convention

The swift calling convention “swiftcc” together with the “swifterror” and 
“swiftself” attribute will change how many registers this calling convention 
will use for passing arguments and returning values. Furthermore, the 
“swifterror” and “swiftself” attribute will cause llvm to put the parameter 
marked with this attribute into a specific register at the call side.

The swift compiler will use this convention for native swift functions. We have 
to be able to call native swift functions from the runtime so there is also 
support in clang to define/declare functions with this calling convention in 

This might have implications on the debugger.

My current plan is to finish the swift/llvm side of this work in the next 
couple weeks. There is a prototype at 
https://github.com/aschwaighofer/swift/tree/native_calling_convention_wip that 
can be tried out today.

There are two radars that track work related to lldb and dwarf support:

<rdar://problem/24489517> DWARF support for the new Swift calling convention
<rdar://problem/25471028> LLDB support for new Swift calling convention


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