[LLVMdev] Building llvm from source with clang instead of gcc
eldlistmailingz at tropicsoft.com
Sat Jan 5 20:08:49 PST 2013
On 1/5/2013 8:01 PM, Justin Holewinski wrote:
> On Sat, Jan 5, 2013 at 5:59 PM, Edward Diener
> <eldlistmailingz at tropicsoft.com <mailto:eldlistmailingz at tropicsoft.com>>
> On 01/05/2013 01:11 PM, Dmitri Gribenko wrote:
> On Sat, Jan 5, 2013 at 7:48 PM, Edward Diener
> <eldlistmailingz at tropicsoft.__com
> <mailto:eldlistmailingz at tropicsoft.com>> wrote:
> I actually found out that llvm/configure will choose clang
> if it is
> found in the path. This contradicts what is written at
> where it says it
> will use the first GCC it finds. Perhaps that explanation
> needs to be
> Updated docs in r171630.
> Finally I found that if llvm/configure uses clang instead of
> gcc, it
> invariably fails on my Linux distros because it is using the gcc
> distributed included directories and an earlier version of
> clang will
> often fail with these gcc header files. Once I force
> llvm/configure to
> use gcc, building llvm/clang succeeds again.
> Right. Maybe we need to skip old clang versions in this case.
> I think this should be done until clang can use its own header files
> and libraries, when it is installed as a binary, rather than the
> ones that gcc installs. In fact I am a bit amazed that clang does
> not already have its own header files and libraries for use when one
> tries llvm/configure and it sets up llvm's build system to use clang
> as its compiler. Is this the fault of clang or is it the fault of
> the llvm/configure system ?
> There is no complete solution for LLVM-only headers/libraries yet on
> Linux. For C++, you can use libc++, but you still need some GCC
> libraries (or alternatives). And you will at least need glibc or
> another compatible C runtime.
Should not what it is needed by clang to work correctly under Linux be
posted somewhere on the clang Getting Started web page ? Even what you
posted above requires guesswork on my part.
Am I supposed to install libc++ and glibc in a Linux distro for clang to
work correctly ?
Which versions do I need ?
How do I tell clang what to use or is this automatically figured out by
Will llvm/configure use these libraries if I let it choose a clang
binary in order to build the latest llvm/clang from source ?
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