[llvm-dev] Orc JIT vs. devtoolset-6
Geoff Levner via llvm-dev
llvm-dev at lists.llvm.org
Wed Aug 28 07:21:47 PDT 2019
The libstdc++.so file that comes with devtoolset-6 is actually not a DSO
but a small text file containing this:
/* GNU ld script
Use the shared library, but some functions are only in
the static library, so try that secondarily. */
INPUT ( /usr/lib64/libstdc++.so.6 -lstdc++_nonshared )
So the question, I think, is: what exactly does the GNU linker do with this
information, and is there a way to replicate its behavior in Orc JIT?
On Wed, Aug 28, 2019 at 9:16 AM Geoff Levner <glevner at gmail.com> wrote:
> [I am reposting this with a different title and other changes, because I
> am fairly confident our problem is related to Red Hat's developer toolset.]
> Greetings, LLVM wizards.
> We have an application that uses Clang and Orc JIT (v1) to compile and
> execute C++ code on the fly. If a C++ module calls functions from external
> libraries, we add them via DynamicLibrary::LoadLibraryPermanently().
> Recently we moved to gcc 6.3.1 to build our application, using Red Hat's
> devtoolset-6 on CentOS, and this seems to create problems when a module
> calls functions from the STL. If a module calls this swap() function for
> input streams, for example:
> #include <fstream>
> std::ifstream stream1, stream2;
> When we run the constructors for the module, we get undefined STL symbols.
> It turns out that the missing symbols are defined not in the runtime DSO
> (in /usr/lib64) but in an archive file installed with the developer toolset:
> Apparently the linker performs some magic allowing an application compiled
> and linked with gcc 6.3.1 to run on a system with an older version of the
> STL (from gcc 4.8.5), augmenting the old DSO with stuff that is linked in
> SO my question is: is there any way to reproduce that magical behavior in
> an Orc JIT compiler, so that code can link properly with the STL?
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the llvm-dev