[swift-dev] Help needed: Removing inout shadow copy from SILGen

[Adrian Prantl]

On Jun 9, 2016, at 9:55 AM, Joe Groff <jgroff at apple.com> wrote:
> 
> 
>> On Jun 8, 2016, at 7:38 PM, Daniel Duan via swift-dev <swift-dev at swift.org> wrote:
>> 
>> Hi all,
>> 
>> I'm resuming work on removing the SILGen for the inout shadow copy. Making
>> this change involes quite a bit of tests updates.  I'd love some one to review
>> this commit in SILGenProlog.cpp before I dive back into the deep end:
>> 
>> https://github.com/dduan/swift/commit/e56d73c065bec7bdde7c0ffee42b808d1bb52d74
>> 
>> (It's +5, -12, a small patch).
>> 
>> Is this on the right track?
> 
> The variable binding looks great. We might need to coordinate with the debugger to ensure we still emit debug info the way lldb expects it; cc'ing Adrian and Enrico.
> 
> -Joe

The diff looks generally reasonable to me. You will probably have to update a bunch of debug info testcases along with this change.

You can run the LLDB test suite with by running
  $ build-script -r -l -t -- --skip-test-cmark --skip-test-swift --lldb-test-with-curses --lldb-use-system-debugserver

Since I missed the original discussion, I’m curious about the context though: under what circumstances is an inout argument be passed by value and can it ever be a let binding?

-- adrian