LLVM compiler for production code?

Question

I have a question concerning the LLVM compiler:

I would like to use it to compile my Objective-C source code for Mac and iOS and from their release notes it seems that LLVM is stable enough for using this.

Having made good experiences with the LLVM I would also like to use it to compile C++ or Objective-C++. However it is not clear to me if I should still use the hybrid LLVM-GCC compiler (the GCC parser and the LLVM code generator) or the pure LLVM compiler.

I am also unsure about the new C++ standard library and if I should use it and how I would make the transition from GNU's libstdc++.

The Questions

Which compiler would one use today to generate fast production quality code from C++: the LLVM-GCC hybrid compiler or pure LLVM?
Should one migrate the C++ standard library from GNU's libstdc++ to the new libc++ library created by the LLVM project?

Any comments and hints are appreciated.

I am feeling a bit unsure about LLVM for arm as there were some crashes when using this code on armv6 devices. — GorillaPatch, Apr 07 '11 at 21:39
I was amazed to learn this tidbit: http://stackoverflow.com/questions/5524906/gcc-thumb-support-can-it-be-turned-off-for-just-one-module/5525372#comment-6276408 — Fattie, Apr 07 '11 at 21:46
Note that this is an old question. Apple's current developer tools use LLVM; GCC is gone. — Kristopher Johnson, Jul 25 '12 at 11:48

score 7 · Accepted Answer · answered Apr 07 '11 at 09:39

Several questions asked here, I'll try to answer all of them.

There is no "pure LLVM compiler". LLVM is a set of libraries which do code optimization and code generation . There are several C/C++ frontends which can be hooked to LLVM. Among them are clang and llvm-gcc. See http://llvm.org/ for more information about various components of LLVM Compiler Infrastructure. As written at http://llvm.org/docs/ReleaseNotes.html, llvm-gcc is EOL since LLVM 2.9 release, so you'd better use clang, because it will certainly be developed and maintained in the future.
libc++ is still in development, so for production you should use vendor-provided C++ (libstdc++ in your case).

do you know if DragonEgg (which should replace llvm-gcc) is production ready ? — Matthieu M., Apr 08 '11 at 16:16
@Matthieu: I don't really think so. Right now only Duncan is working on it. Testing by a wider audience might help to obtain "production-ready" tag quite fast though. — Anton Korobeynikov, Apr 08 '11 at 18:15

score 0 · Answer 2 · answered Aug 07 '11 at 16:43

Remember, all this stuff is changing, so benchmarks gets easily outdated.

I've found following report interesting, not only as a kind of benchmark, but it seems showing some LLVM vs GCC compiler differences : Clang/LLVM Maturity Evaluation Report by Dominic Fandrey

LLVM compiler for production code?

The Questions

2 Answers2