[LLVMdev] AddressSanitizer+CMake unittest question

[Alexey Samsonov]

And one more question regarding ASan cmake build.
Currently unittests are fine, but regular "clang -faddress-sanitizer" is
not:

current cmake build stores libclang_rt.asan-x86_64.a together with all the
LLVM libs
(in $build_path/lib/libclang_rt.asan-x86_64.a), but the Clang driver looks
for asan runtime
in clang resource dir:
$build_path/lib/clang/3.2/lib/linux/libclang_rt.asan-x86_64.a). I can
try to find a way to how this can be fixed, but probably you can tell the
answer right away.

On Tue, Jun 26, 2012 at 11:41 AM, Chandler Carruth <chandlerc at google.com>wrote:

> On Tue, Jun 26, 2012 at 12:37 AM, Alexey Samsonov <samsonov at google.com>
> wrote:
> >
> >
> >
> > On Tue, Jun 26, 2012 at 11:06 AM, Chandler Carruth <chandlerc at google.com>
> wrote:
> >>
> >> On Mon, Jun 25, 2012 at 7:38 AM, Kostya Serebryany <kcc at google.com>
> wrote:
> >> >
> >> >
> >> >
> >> > On Mon, Jun 25, 2012 at 5:43 PM, Kostya Serebryany <kcc at google.com>
> wrote:
> >> >>
> >> >>
> >> >>
> >> >> On Mon, Jun 25, 2012 at 4:00 PM, Chandler Carruth <
> chandlerc at google.com> wrote:
> >> >>>
> >> >>> Context: I'm trying to implement support for ASan's unittest suite
> in CMake. This is ... quite challenging.
> >> >>>
> >> >>> I think I can get it to work with one significant caveat: it will
> require manual dependency management. None of the automatic header
> tracking. I think this is fine in some cases, and not so fine in other
> cases. Let me explain.
> >> >>>
> >> >>> It feels like these tests are really comprised of two distinct
> collections of tests:
> >> >>>
> >> >>> 1) Those that rather directly test the ASan runtime. These do not
> rely upon the compiler instrumenting the code, and simply exercise the
> runtime library directly.
> >> >>> 2) Those that expect to be instrumented by the compiler, and
> exercise the runtime through GoogleTest's death tests on seemingly
> innocuous code.
> >> >>>
> >> >>> For the first bucket, there is no problem. We should be able to
> handle these easily.
> >> >>>
> >> >>> For the second bucket, this can be a bit tricky. It requires
> compiling the tests with a custom compiler and flags. Let's talk about the
> options for supporting this case.
> >> >>>
> >> >>> A) We could require the host compiler to have support for
> -faddress-sanitizer, but ensure that the just-built runtime library is used
> rather than the host compiler's runtime library.
> >> >>> B) We can depend upon the Clang built in the same
> LLVM/Clang/CompilerRT checkout, and provide a custom compilation strategy
> to use it to instrument the unittest code.
> >> >>>
> >> >>>
> >> >>> Option A has fairly obvious problems: it introduces version skew
> into the equation, and would require a full bootstrap to test new
> instrumentation. However, it plays very nicely with the build system,
> requiring no special magic. It also would "Just Work" in the
> cross-compilation scenario, as much as any unittest would.
> >> >>>
> >> >>> Option B avoids any version skew issues, but at the cost of
> requiring us to implement a "complete" custom compilation strategy for
> these source files. At the very least, this will not be portable and thus
> will only be enabled on a few platforms, and it will not get automatic
> header dependency tracking.
> >> >
> >> >
> >> > B is highly preferable.
> >> > I.e.:
> >> >   1. Build clang
> >> >   2. Build asan-rt (doesn't not matter with which compiler)
> >> >   3. build asan-rt-tests using clang from #1
> >> > This is what we use now anyway.
> >> > There could of course be dependencies between asan-rt and
> asan-rt-tests, but even worth, there could be dependencies between the
> instrumentation module in LLVM and asan-rt-tests.
> >>
> >> Ok... :: sigh :: Have to go and make this hard on me.
> >>
> >> An additional constraint that would make this slightly easier: for the
> >> tests which require instrumentation, could they strictly avoid
> >> including headers outside of the test-helper headers? That is, none of
> >> the libasan headers themselves.
> >
> >
> > Um, I guess so. AFAIR, it is true even now. I assume, including gtest
> headers is a
> > separate problem?
>
> I can make that work through dirty dirty hacks. The various different
> sanitizer runtimes are actually harder to track and predict.
>



-- 
Alexey Samsonov, MSK
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120711/cb7f06be/attachment.html>