- When I run configure, it finds the wrong C compiler.
The configure script attempts to locate first gcc and
then cc, unless it finds compiler paths set in CC and
CXX for the C and C++ compiler, respectively.
If configure finds the wrong compiler, either adjust your
PATH environment variable or set CC and CXX
- I compile the code, and I get some error about /localhome.
There are several possible causes for this. The first is that you
didn't set a pathname properly when using configure, and it
defaulted to a pathname that we use on our research machines.
Another possibility is that we hardcoded a path in our Makefiles. If
you see this, please email the LLVM bug mailing list with the name of
the offending Makefile and a description of what is wrong with it.
- The configure script finds the right C compiler, but it
uses the LLVM linker from a previous build. What do I do?
The configure script uses the PATH to find
executables, so if it's grabbing the wrong linker/assembler/etc, there
are two ways to fix it:
- Adjust your PATH environment variable so that the
correct program appears first in the PATH. This may work,
but may not be convenient when you want them first in your
path for other work.
- Run configure with an alternative PATH that
is correct. In a Borne compatible shell, the syntax would be:
PATH= ./configure ...
This is still somewhat inconvenient, but it allows
configure to do its work without having to adjust your
- When creating a dynamic library, I get a strange GLIBC error.
Under some operating systems (i.e. Linux), libtool does not work correctly
if GCC was compiled with the --disable-shared option. To work around this,
install your own version of GCC that has shared libraries enabled by
- I've updated my source tree from CVS, and now my build is trying to
use a file/directory that doesn't exist.
You need to re-run configure in your object directory. When new Makefiles
are added to the source tree, they have to be copied over to the object
tree in order to be used by the build.
- I've modified a Makefile in my source tree, but my build tree keeps
using the old version. What do I do?
If the Makefile already exists in your object tree, you can just run the
following command in the top level directory of your object tree:
./config.status <relative path to Makefile>
If the Makefile is new, you will have to modify the configure script to copy
- I've upgraded to a new version of LLVM, and I get strange build
Sometimes changes to the LLVM source code alters how the build system
works. Changes in libtool, autoconf, or header file dependencies are
especially prone to this sort of problem.
The best thing to try is to remove the old files and re-build. In most
cases, this takes care of the problem. To do this, just type make
clean and then make in the directory that fails to build.
- I've built LLVM and am testing it, but the tests freeze.
This is most likely occurring because you built a profile or release
(optimized) build of LLVM and have not specified the same information on
the gmake command line.
For example, if you built LLVM with the command:
...then you must run the tests with the following commands:
- Why do test results differ when I perform different types of
The LLVM test suite is dependent upon several features of the LLVM tools
First, the debugging assertions in code are not enabled in optimized or
profiling builds. Hence, tests that used to fail may pass.
Second, some tests may rely upon debugging options or behavior that is
only available in the debug build. These tests will fail in an optimized
or profile build.