compiler.blacklist

[Ryan Schmidt]

On May 3, 2014, at 07:28, Craig Treleaven wrote:
> At 8:34 PM -0500 5/2/14, Ryan Schmidt wrote:
>> On May 2, 2014, at 20:20, Craig Treleaven wrote:
>>> 
>>> For my mythtv-core.xx ports, I want to blacklist clang prior to XCode 5, so I added:
>>> 
>>> compiler.blacklist-append { clang <= 500.2.79 } \
>> >    macports-clang*
>>> 
>>> That doesn't work when I build on Lion with XCode 4.3.3 (clang 318.0.61)--it tries to build with clang and falls over.
>> 
>> That sounds like you may not have included the compiler_blacklist_versions 1.0 portgroup. If you do that, it should do what you say: blacklist all MacPorts clangs, and Xcode clangs less than 500. So on Macs with Xcode 4 or earlier, you'll be building with llvm-gcc-4.2 or gcc-4.2. Is that really what you want? If Xcode 5's clang is ok, presumably MacPorts clang 3.5 would work too, maybe even 3.4, and those would probably be preferable to the old llvm-gcc or gcc.
> 
> You are indeed correct; the line to add the compiler_blacklist_versions portgroup got dropped somewhere along the way.  And the buildbots were down when the change was committed.
> 
> Is this something that lint could be made to pick up?  ie a compiler version comparison used but required PortGroup missing?

Good idea. Done in r119714.

Ultimately the workings of the compiler_blacklist_versions portgroup should be incorporated into base instead.


> Pre-XCode 5, Myth builds and runs fine with gcc and llvm-gcc.  The the upstream project only recently put in some fixes that allow it to build with later versions of clang.
> 
> Re MacPorts-supplied versions of clang, I simply haven't tried to build with them.  I cribbed that section from qt4-mac port since it had the same issue with LIBRARY_PATH that I had.  The 'macports-clang*' exclusion is probably extraneous but I wanted to be sure to use know-working compilers, only.

There may be some small difference between MacPorts clang and Xcode clang, but the primary difference is the version numbering.

According to our XcodeVersionInfo wiki page, Xcode 5.0 came with “Apple LLVM version 5.0 (clang-500.2.75) (based on LLVM 3.3svn)”. “LLVM 3.3svn” means that this version corresponds to some version of LLVM that is greater than 3.3 and less than 3.4. So if you already know that Xcode 5’s clang works, and earlier Xcodes’ clangs don’t work, then you also know that MacPorts clang 3.3 and earlier won’t work either, and MacPorts clang 3.4 and later should work.