MacPorts on Lion (common issues, fixes, and workarounds)

[Jeremy Huddleston]

On Jul 20, 2011, at 10:24 AM, Jeremy Lavergne wrote:

>> Clang is LLVM.  You probably mean "llvm-gcc" rather than "llvm"?
> 
> Yup, llvm-gcc is what I meant, not clang.
> 
> Is it correct to say?
> * llvm-gcc is llvm 2
> * clang is llvm 3

There are too many differnet versions floating around for me to keep it all straight.  "LLVM 2" and "LLVM 3" are not good descriptions because the llvm version refers to the backend.  I think Apple is calling llvm-gcc the "LLVM Compiler version 1" and differnet versions of clang can be referred to as "LLVM Compiler version X" where X is the "Apple clang version X" that you see in the output of 'clang --version'

These I know:
Apple's llvm-gcc-4.2 is based on the gcc-4.2 frontend and llvm-2.9 backend.
XCode 3.2's clang is "Apple clang version 1.7" and based on the llvm-2.9 backend

I don't have XCode 4.0 on one of my machines, but I believe it is:
XCode 4.0's clang is "Apple clang version 2.0" and based on the llvm-2.9 backend

Can someone please verify or correct that?

> With all this trouble, I wonder why we don't just stick to gcc until we
> can leap to clang.

If you haven't already, I suggest you get ADC access and watch the WWDC talks.  They're quite informative.

There will always be issues when changing compilers, even more-so leaping from gcc to clang.  I want to be on clang as much as the next person, but it would be an even bigger headache right now.  I believe we should update base to choose clang as default with the next version of XCode (4.2).  I've been using clang on one machine and llvm-gcc on another for quite some time, and both seem very solid.

--Jeremy