<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jan 4, 2018 at 3:04 PM, Dimitry Andric <span dir="ltr"><<a href="mailto:dimitry@andric.com" target="_blank">dimitry@andric.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 3 Jan 2018, at 18:24, James Y Knight via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br>
><br>
> I'd like to propose that trunk always have a version number which is in between versions used by the previous release branch, and before the versions used in the next release branch.<br>
><br>
> Right now, trunk is sharing the 7.0.0 number, which will also be used by the next release 4 months from now. Since some people use and release snapshots of clang from trunk (e.g. the Android NDK), it'd be helpful to be able to more reliably distinguish this.<br>
><br>
> This is both confusing in general, and means that if you're writing an #if checking the version (which of course ought to be avoided when possible, but is sometimes the best answer), it is more difficult than it needs to be to do the right thing.<br>
><br>
> E.g., a check like this will erroneously think that trunk, now, is Clang 7, and has fixed this hypothetical bug.<br>
> #if __clang_major__ >= 7<br>
> // Do something which was buggy before Clang 7.<br>
> #endif<br>
<br>
</span>Yes, this is often done in the FreeBSD ports system, sometimes using the major version in the source, but more often in Makefiles, where the X.Y.Z version is condensed to just 'XY', as shown in <a href="https://github.com/freebsd/freebsd-ports/blob/master/lang/v8/Makefile#L36" rel="noreferrer" target="_blank">https://github.com/freebsd/<wbr>freebsd-ports/blob/master/<wbr>lang/v8/Makefile#L36</a> :<br>
<br>
.if ${COMPILER_TYPE} == clang<br>
CXXFLAGS+= -Wno-nested-anon-types -Wno-unused-function -Wno-unused-private-field<br>
MAKE_ENV+= LINK=clang++<br>
.if ${COMPILER_VERSION} >= 34<br>
CXXFLAGS+= -Wno-unused-const-variable<br>
.if ${COMPILER_VERSION} >= 35<br>
CXXFLAGS+= -Wno-tautological-undefined-<wbr>compare<br>
.if ${COMPILER_VERSION} >= 36<br>
CXXFLAGS+= -Wno-unused-local-typedef<br>
.endif<br>
.endif<br>
.endif<br></blockquote><div><br></div><div><br></div><div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">That seems a very unfortunate scheme, especially considering the differing definition of the same-named variable in FreeBSD core's makefiles:</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><a href="https://github.com/freebsd/freebsd/blob/d67d8724ce34e69801d9018e6bf76afed2ca3841/share/mk/bsd.README">https://github.com/freebsd/freebsd/blob/d67d8724ce34e69801d9018e6bf76afed2ca3841/share/mk/bsd.README</a></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">"""</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">COMPILER_VERSION<br></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="white-space:pre"> </span>A numeric constant equal to:</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="white-space:pre"> </span> major * 10000 + minor * 100 + tiny</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="white-space:pre"> </span>for the compiler's self-reported version.</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">"""</div><br></div><div>I don't think that's a good reason to not use X.99 for clang versions, however -- the FreeBSD makefile can easily translate that to X9 if it likes, or, change their definition.</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">> I see a couple alternatives for improving this:<br>
><br>
> 1. Change the way we version trunk.<br>
><br>
> After creating release branch for X.0, change trunk to version X.99 instead of (X+1).0. Thus, trunk would always have a .99 minor release. The release branch would be incremented from X.99 to (X+1).0 upon creation.<br>
><br>
> 6.99.0-------7.99.0-----------<wbr>-----8.99.0------...<br>
> \-7.0.0----7.0.1 \-8.0.0----8.0.1<br>
<br>
</span>Probably 6.9, 7.9 and such would be enough, since 7.1 and 7.2 won't ever appear in the recent "new versioning scheme", and even older versions never reached past the .9 second level version?<br></blockquote><div><br></div><div>Perhaps so, but I greatly prefer the implication that "99" has that it's not a real version, which "9" is much less suggestive of.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
<br>
> 2. Change the minor version of the first release.<br>
><br>
> Leave trunk as X.0 as now, but on the release branch, increment the version to X.1.<br>
><br>
> 7.0.0--------8.0.0------------<wbr>-----9.0.0------...<br>
> \-7.1.0----7.1.1 \-8.1.0----8.1.1<br>
><br>
> I'd marginally favor #2, because that's similar to how GCC is doing it now, but what do others think?<br>
<br>
</span>As far as I can see, the first variant would not really work for the FreeBSD ports system as-is, since it has silently assumed the second-level version number to be smaller than 10. But maybe I'm reading the ports infrastructure makefiles incorrectly.<br>
<br>
That said, as long as there is a way to identify the (end-user visible) clang or llvm version where certain features or bugs were introduced, both variants would be OK.<br>
<span class="HOEnZb"><font color="#888888"><br>
-Dimitry<br>
<br>
</font></span></blockquote></div><br></div></div>