<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Mar 28, 2014 at 10:56 PM, Greg Fitzgerald <span dir="ltr"><<a href="mailto:garious@gmail.com" target="_blank">garious@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">> Note that ASan tests on Android require llvm-symbolizer binary.<br>
<br>
</div>That's a really good point. And I see that llvm-symbolizer can't just<br>
be pulled into compiler-rt because it has dependencies on DebugInfo,<br>
Object, and Support libraries. </blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
This throws a big wrench in Alexey's plan to have the native<br>
compiler-rt build generate the cross-compiled binaries for all<br>
supported targets. We would need to do the same in the llvm repo.<br>
The alternative is to run a separate cross-compiled build for each<br>
architecture. :-/<br></blockquote><div><br></div><div>Yes, this llvm-symbolizer part is frustrating... I though we can get away</div><div>with it at first, as llvm-symbolizer is optional, and we generally won't be able</div>
<div>to produce working *binaries* for architectures different from the host one (we might not have a linker, for instance).</div><div>Android with its NDK looks like an exception, though.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=""><br>
<br>
> Yes, so "ninja install" is optional.<br>
<br>
</div>But the 'install' depends on the 'all' target.<br>
<br>
-Greg<br>
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On Fri, Mar 28, 2014 at 12:39 AM, Evgeniy Stepanov<br>
<div class="HOEnZb"><div class="h5"><<a href="mailto:eugeni.stepanov@gmail.com">eugeni.stepanov@gmail.com</a>> wrote:<br>
> On Thu, Mar 27, 2014 at 10:18 PM, Greg Fitzgerald <<a href="mailto:garious@gmail.com">garious@gmail.com</a>> wrote:<br>
>>> Alexey's approach with CMake sub-projects.<br>
>><br>
>> I prefer that direction as well, but what I've proposed is a solution<br>
>> that works today. To support cross-compilation, we'll need to loop<br>
>> over each supported arch (llvm-config --targets-built), then loop over<br>
>> each supported triple for each arch (hard-coded map?), and then pair<br>
>> up each triple with a sysroot (system paths provided by the user).<br>
>><br>
>><br>
>>> I think it already copies<br>
>>> compiler-rt build products to the parent build directory, right?<br>
>><br>
>> The Android compiler-rt build does this, but in an unnecessarily<br>
>> complex way. My proposal is a simplification of that process. What<br>
>> is described in "llvm/cmake/platforms/Android.cmake" is to build<br>
>> llvm+clang for the host architecture and then run a second build to<br>
>> cross-compile llvm+compiler-rt to get a the ASan shared object and<br>
>> test suite. Instead, I propose building only llvm for the host<br>
>> architecture (for the purpose of building llvm-config) and then only<br>
>> compile compiler-rt for Android. No need to build clang or to<br>
>> cross-compile llvm.<br>
>><br>
>><br>
>>> Requiring that llvm is installed complicates things.<br>
>><br>
>> Sorry for the confusion. By "llvm install directory", I don't mean to<br>
>> install llvm to the root directory. I'm referring to the intermediary<br>
>> directory pointed to by CMAKE_INSTALL_PREFIX. When you run "ninja<br>
>> install", the build populates this directory with only the libs,<br>
>> headers, docs, and executables that the LLVM build intends customers<br>
>> to use directly. In the case of compiler-rt, we need LLVM's<br>
>> "bin/llvm-config" to determine the build mode, flags, and targets<br>
>> available.<br>
><br>
> Yes, so "ninja install" is optional. This should work with LLVM build<br>
> directory just as well.<br>
><br>
>><br>
>><br>
>>> This should not be too hard to fix.<br>
>><br>
>> Porting the LLVM build to Android? That seems like a more challenging<br>
>> solution than to cut out the unused cross-compiled llvm build.<br>
><br>
> Note that ASan tests on Android require llvm-symbolizer binary.<br>
> Building just compiler-rt for the target would not be enough.<br>
><br>
>><br>
>> -Greg<br>
>><br>
>> On Thu, Mar 27, 2014 at 1:14 AM, Evgeniy Stepanov<br>
>> <<a href="mailto:eugeni.stepanov@gmail.com">eugeni.stepanov@gmail.com</a>> wrote:<br>
>>> I'd prefer something based on Alexey's approach with CMake<br>
>>> sub-projects. I think it already copies compiler-rt build products to<br>
>>> the parent build directory, right?<br>
>>><br>
>>> Requiring that llvm is installed complicates things.<br>
>>><br>
>>> On Thu, Mar 27, 2014 at 5:00 AM, Greg Fitzgerald <<a href="mailto:garious@gmail.com">garious@gmail.com</a>> wrote:<br>
>>>> The build for the Android sanitizers is unique in that it needs to<br>
>>>> link against the Android system libraries to create a shared object<br>
>>>> and its test suites. The current solution to build ASan is to drop<br>
>>>> the compiler-rt repo into the llvm source tree and cross-compile the<br>
>>>> llvm build for Android. This is a bit awkward for few reasons:<br>
>>>><br>
>>>> 1) Not all of llvm can be cross-compiled for Android. "ninja all"<br>
>>>> causes expected build errors.<br>
>>><br>
>>> This should not be too hard to fix.<br>
>>><br>
>>>> 2) The sanitizers don't depend on any LLVM libraries, only llvm-config<br>
>>>> for its build configuration.<br>
>>>> 3) No "install" rule. Instead, you cherry-pick files from the build directory.<br>
>>>><br>
>>>> Building against the LLVM install directory cleans this up nicely and<br>
>>>> as it turns out, this mostly works today (see CMake configuration<br>
>>>> below). The only missing pieces are that the shared object is not<br>
>>>> added to the install directory and the test suites are not built. Is<br>
>>>> this a build configuration you'd consider using?<br>
>>>><br>
>>>> $ cmake -G Ninja .. \<br>
>>>> -DCMAKE_INSTALL_PREFIX=ship \<br>
>>>> -DCMAKE_C_COMPILER=arm-linux-androideabi-gcc \<br>
>>>> -DCMAKE_CXX_COMPILER=arm-linux-androideabi-g++ \<br>
>>>> -DCMAKE_PREFIX_PATH=`pwd`/../../llvm/out/ship \<br>
>>>> -DANDROID=1 \<br>
>>>> -DCMAKE_SYSTEM_NAME=Linux \<br>
>>>> -DCMAKE_C_FLAGS=--sysroot=$(ndkDir)/platforms/android-19/arch-arm \<br>
>>>> -DCMAKE_CXX_FLAGS=--sysroot=$(ndkDir)/platforms/android-19/arch-arm<br>
>>>> ...<br>
>>>> $ ninja install<br>
>>>> ...<br>
>>>> [68/68]<br>
>>>> -- Install configuration: "Release"<br>
>>>> -- Installing: ship/include/sanitizer/asan_interface.h<br>
>>>> -- Installing: ship/include/sanitizer/common_interface_defs.h<br>
>>>> -- Installing: ship/include/sanitizer/dfsan_interface.h<br>
>>>> -- Installing: ship/include/sanitizer/linux_syscall_hooks.h<br>
>>>> -- Installing: ship/include/sanitizer/lsan_interface.h<br>
>>>> -- Installing: ship/include/sanitizer/msan_interface.h<br>
>>>> -- Installing: ship/include/sanitizer/tsan_interface_atomic.h<br>
>>>> -- Installing: ship/asan_blacklist.txt<br>
>>>> -- Installing: ship/bin/asan_device_setup<br>
>>>><br>
>>>> Thanks,<br>
>>>> Greg<br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div>Alexey Samsonov, MSK</div>
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