Er... so to answer my own question, for posterity, to set up a new
project (based on the sample project) to link to the core LLVM
library, all you need to do is add the following line to the relevant
make file:
LINK_COMPONENTS = core
So for my example below, I added the above line to tools/sample/Makefile.
Perhaps a mention of this could be added to the "Creating an LLVM
Project" page?
Thanks,
Lane
On Mon, Apr 14, 2008 at 8:57 PM, Lane Schwartz <dowobeha at gmail.com>
wrote:> Hi all,
>
> I have a new sample project set up in my llvm/projects directory, and
> I'd eventually like my frontend to generate an LLVM IR tree. To do so,
> I believe I need to link to the appropriate LLVM libraries. That's
> where I'm stuck.
>
> I can't seem to find any specific documentation that describes how to
> set up a new project to link to LLVM libraries.
>
> To get started, I added a couple lines to the tools/sample/main.cpp
> file in my project:
>
> #include "llvm/Module.h"
> ...
> // Inside main
> Module* module = new Module("myfirst");
>
> Not much, but I just want to verify that I can successfully compile
> and link using an LLVM IR class.
>
> Presumably, I need to make some additions to configure.ac and the
> tools/sample/Makefile, but I can't figure out what those changes
> should be. Since the linker doesn't know how to get the library, I get
> an error now when I run make:
>
> $ make
> llvm[2]: Compiling sample.c for Release build
> llvm[2]: Building Release Archive Library libsample.a
> llvm[2]: Compiling calc.cpp for Release build
> llvm[2]: Building Release Archive Library libcalc.a
> llvm[2]: Compiling main.cpp for Release build
> main.cpp: In function 'int main(int, char**)':
> main.cpp:16: warning: unused variable 'module'
> llvm[2]: Linking Release executable Sample (without symbols)
> Undefined symbols:
> "llvm::Module::Module(std::basic_string<char,
> std::char_traits<char>, std::allocator<char> >
const&)", referenced
> from:
> _main in main.o
> ld: symbol(s) not found
> collect2: ld returned 1 exit status
> make[2]: *** [/opt/src-llvm/projects/myproject/Release/bin/Sample] Error 1
> make[1]: *** [all] Error 1
> make: *** [all] Error 1
>
>
> Since there is no configure.ac file or Makefile listed with the
> Kaleidoscope tutorial (I even looked around the svn repository for
> one...), I took a look at what Stacker uses, and took the following
> from the Stacker configure.ac file:
>
> dnl
**************************************************************************
> dnl * Set the location of various third-party software packages
> dnl
**************************************************************************
>
> dnl Location of LLVM source code
> AC_ARG_WITH(llvmsrc,AS_HELP_STRING([--with-llvmsrc],[Location of LLVM
> Source Code]),AC_SUBST(LLVM_SRC,[$withval]),AC_SUBST(LLVM_SRC,[`cd
> ${srcdir}/../..; pwd`]))
> AC_CONFIG_COMMANDS([llvm_src],[],[llvm_src=$LLVM_SRC])
>
> dnl Location of LLVM object code
> AC_ARG_WITH(llvmobj,AS_HELP_STRING([--with-llvmobj],[Location of LLVM
> Object Code]),AC_SUBST(LLVM_OBJ,[$withval]),AC_SUBST(LLVM_OBJ,[`cd
> ../..; pwd`]))
> AC_CONFIG_COMMANDS([llvm_obj],[],[llvm_obj=$LLVM_OBJ])
>
>
> Since I'm trying to use the Module class, I also tried adding this
> line to tools/sample/Makefile:
>
> LINK_COMPONENTS = llvmcore
>
>
> After making those changes, the linking still fails.
>
> $ make
> llvm[2]: Compiling sample.c for Release build
> llvm[2]: Building Release Archive Library libsample.a
> llvm[2]: Compiling calc.cpp for Release build
> llvm[2]: Building Release Archive Library libcalc.a
> llvm-config: unknown component name: llvmcore
> llvm-config: unknown component name: llvmcore
> llvm[2]: Compiling main.cpp for Release build
> main.cpp: In function 'int main(int, char**)':
> main.cpp:16: warning: unused variable 'module'
> llvm[2]: Linking Release executable Sample (without symbols)
> Undefined symbols:
> "llvm::Module::Module(std::basic_string<char,
> std::char_traits<char>, std::allocator<char> >
const&)", referenced
> from:
> _main in main.o
> ld: symbol(s) not found
> collect2: ld returned 1 exit status
> make[2]: *** [/opt/src-llvm/projects/myproject/Release/bin/Sample] Error 1
> make[1]: *** [all] Error 1
> make: *** [all] Error 1
>
> Any tips or pointers would be greatly appreciated. It seems that
> linking to the LLVM libraries is a pretty common thing that someone
> starting a new project might want to do. :) I'd love to figure out
> how.
>
> Cheers,
> Lane
>
--
When a place gets crowded enough to require ID's, social collapse is not
far away. It is time to go elsewhere. The best thing about space travel
is that it made it possible to go elsewhere.
-- R.A. Heinlein, "Time Enough For Love"