[cfe-dev] Problem linking example program with DataFlow Sanitizer

[Alexey Samsonov]

On Wed, May 7, 2014 at 4:31 PM, Peter Collingbourne <peter at pcc.me.uk> wrote:

> On Wed, May 07, 2014 at 05:52:25PM -0500, Frederico Araujo wrote:
> > Hi Peter,
> >
> > Thank you for your reply.
> >
> > I'm still having problems even after using cmake. Please see my comments
> > below.
> >
> > On Wed, May 7, 2014 at 4:16 PM, Peter Collingbourne <peter at pcc.me.uk>
> wrote:
> >
> > > Hi Frederico,
> > >
> > > On Wed, May 07, 2014 at 03:43:07PM -0500, Frederico Araujo wrote:
> > > > Hi,
> > > >
> > > > I'm trying to compile the example program from the DataFlow Sanitizer
> > > page (
> > > > http://clang.llvm.org/docs/DataFlowSanitizer.html) without success.
> I
> > > > receive a number of errors when trying to compile the example with
> clang:
> > > >
> > > > /> clang -fsanitize=dataflow -o labelprop labelprop.c
> > > [...]
> > > > /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/Scrt1.o:
> In
> > > > function `_start':
> > > > (.text+0x20): undefined reference to `main'
> > > [...]
> > > > /tmp/labelprop-bfe82e.o: In function `dfs$main':
> > > > labelprop.c:(.text+0x78): undefined reference to
> `dfs$dfsan_create_label'
> > >
> > > It looks like DFSan wasn't able to find the ABI list file.
> Unfortunately
> > > only the CMake build system currently supports building the ABI list.
> > > Can you please try again with CMake?
> > >
> >
> > I created this simple CMake list file:
> >
> > cmake_minimum_required (VERSION 2.6)
> > project (EXAMPLE)
> > add_executable(labelprop labelprop.c)
> > SET (CMAKE_C_COMPILER   "/usr/bin/clang")
> > SET (CMAKE_C_FLAGS "-fsanitize=dataflow")
> >
> > After building the project with the above configuration, I still get the
> > same errors as before. Anything missing? Perhaps I should say that I'm
> new
> > to cmake :)
>
> Sorry, I meant that you need to compile LLVM/Clang/compiler-rt with CMake
> following the instructions here:
>
> http://llvm.org/docs/CMake.html
>
> > I forgot to ask in my first email: is there any step-by-step instructions
> > on how to compile and get the dataflow sanitizer example working?
>
> It shouldn't take any more than compiling with the -fsanitize=dataflow
> command
> line flag, but admittedly the requirement to build Clang with CMake had not
> been documented. I'll see about documenting it.
>
> > >
> /usr/local/llvm/build/Debug+Asserts/bin/../lib/clang/3.5.0/lib/linux/libclang_rt.dfsan-x86_64.a(sanitizer_deadlock_detector1.o):(.data.rel.ro._ZTIN11__sanitizer9DDetectorE[_ZTIN11__sanitizer9DDetectorE]+0x0):
> > > > undefined reference to `vtable for __cxxabiv1::__class_type_info'
> > >
> > > This would appear to indicate that your sanitizer runtimes were built
> with
> > > RTTI, which is a little surprising. Did you do anything in particular
> to
> > > enable RTTI?
> > >
> >
> > Well, no. I just followed the instructions on the clang webpage on how to
> > compile llvm and clang. I used the trunk versions of everything. I also
> > compiled the optional projects. Could it be the -fsanitizer-dataflow
> option?
>
> So it looks like when built with Makefiles, the dfsan runtime library
> contains
> some object files that were compiled with RTTI. It isn't immediately clear
> why
> this is happening with dfsan and not with the other sanitizer runtimes.
> Alexey,
> do you have any idea?
>

r208268 should help.


>
> In any case, building with CMake should fix this.
>
> Thanks,
> --
> Peter
>



-- 
Alexey Samsonov, Mountain View, CA
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