<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Oct 3, 2017, at 10:32 PM, Jonas B <<a href="mailto:bobergj@gmail.com" class="">bobergj@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><br class=""></div><div class=""><blockquote type="cite" class=""><div class="">On 4 Oct 2017, at 13:36, Slava Pestov <<a href="mailto:spestov@apple.com" class="">spestov@apple.com</a>> wrote:</div><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Oct 3, 2017, at 9:14 PM, Jonas B via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Now I understand that this use-case is deferred for a later separate discussion, but my point here is that the name and the semantics of this attribute should be somewhat “forward-compatilble” with this use-case. “ inlinable” does not sound appropriate, because we don’t want to “inline” (in the C/C++ meaning) declarations into each usage site.</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Instead we want to compile the annotated parts of -all linked modules- as one unit. Basically, for those parts, the module name would just function like a C++ namespace - an input to the symbol name mangling, and then the whole thing could be whole-module-optimized together.</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""></div></blockquote><div class=""><br class=""></div>Yeah, @inlinable does not actually force any kind of inlining to be performed — it declared that the SIL for the function body should be serialized as part of the module.</div><div class=""><br class=""><blockquote type="cite" class=""><div class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">This touches upon another comment someone made previously in this discussion - that access level and compiler visibility should be separate concepts. Because not just public methods, also private methods should be subject to this.<span class="Apple-converted-space"> </span></span></div></blockquote></div><br class=""><div class="">The undocumented @_versioned attribute is currently used to make something visible to the compiler without making it visible in the language. It sounds like there’s some interest in documenting this attribute too — can someone suggest a better name than @_versioned? If we converge on a design here I can incorporate that into the proposal, relaxing the restriction that @inlinable functions can only reference other public functions.</div><div class=""><br class=""></div><div class="">Slava</div></div></div></blockquote></div><div class=""><br class=""></div><div class="">It’s not totally clear to me what @_versioned is supposed to do. Well, it’s kind of clear that if something less-than-public in module A is declared @_versioned then it’s visible to the compiler when compiling module B (which imports module A). But does @_versioned imply @inlineable? If not, what’s the use case for declaring something @_versioned but not @inlineable? Giving some more information to the optimiser without introducing ABI fragility? Why not always do that then?</div><div class=""><br class=""></div></div></div></blockquote></div><br class=""><div class="">@_versioned makes a symbol visible externally without making it visible from the language. There is no requirement that a @_versioned thing is @inlinable. It is used when you want to reference an internal function from an inlinable function. Eg,</div><div class=""><br class=""></div><div class="">internal func myImplDetail() { … }</div><div class=""><br class=""></div><div class="">@inlinable public func myPublicFunction() { myImplDetail() } // error!</div><div class=""><br class=""></div><div class="">—</div><div class=""><br class=""></div><div class=""><div class="">@_versioned internal func myImplDetail() { … }</div><div class=""><br class=""></div><div class="">@inlinable public func myPublicFunction() { myImplDetail() } // OK</div></div><div class=""><br class=""></div><div class="">Slava</div></body></html>