[LLVMdev] Building LLVM with asan

Thu Nov 21 09:08:49 PST 2013

Indeed, removing that flag works fine, the only question is why this is
added in tools/llvm-shlib/Makefile in the first place then and what to do
about it:

ifeq ($(HOST_OS), $(filter $(HOST_OS), Linux GNU GNU/kFreeBSD))
    # Don't allow unresolved symbols.
    LLVMLibsOptions += -Wl,--no-undefined
endif

On Thu, Nov 21, 2013 at 11:53 AM, Alexander Potapenko <glider at google.com>wrote:

> Yeah, it's not linking the runtime because you're building a shared
> library. This is totally ok. In this case there are undefined __asan_*
> symbols that are resolved when an instrumented binary loads your library.
> What's wrong here is that some flag passed to ld prevents it from creating
> undefined symbols (--no-undefined?). This flag must be removed when
> building with ASan.
> This isn't the case on OSX where the runtime is a dynamic library and can
> safely be linked to instrumented dynamic libraries.
> What I meant to say was that it worked for me on OS X on a slightly older
> version of LLVM. Anyway, here's the ld line:
>
>  "/usr/bin/ld" -export-dynamic -z relro --hash-style=gnu --build-id
> --eh-frame-hdr -m elf_x86_64 -shared -o
> /home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib/
> libLLVM-3.5svn.so/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/crti.o
> /usr/lib/gcc/x86_64-linux-gnu/4.8/crtbeginS.o
> -L/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib
> -L/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib
> -L/usr/lib/gcc/x86_64-linux-gnu/4.8
> -L/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu
> -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu
> -L/usr/lib/gcc/x86_64-linux-gnu/4.8/../../.. -L/lib -L/usr/lib -R
> "\$ORIGIN" --whole-archive -lLLVMAnalysis -lLLVMAsmParser -lLLVMAsmPrinter
> -lLLVMBitReader -lLLVMBitWriter -lLLVMCodeGen -lLLVMCore -lLLVMDebugInfo
> -lLLVMExecutionEngine -lLLVMInstCombine -lLLVMInstrumentation
> -lLLVMInterpreter -lLLVMipa -lLLVMipo -lLLVMIRReader -lLLVMLinker -lLLVMLTO
> -lLLVMMC -lLLVMMCDisassembler -lLLVMMCJIT -lLLVMMCParser -lLLVMObjCARCOpts
> -lLLVMObject -lLLVMOption -lLLVMRuntimeDyld -lLLVMScalarOpts
> -lLLVMSelectionDAG -lLLVMSupport -lLLVMTarget -lLLVMTransformUtils
> -lLLVMVectorize -lLLVMX86AsmParser -lLLVMX86AsmPrinter -lLLVMX86CodeGen
> -lLLVMX86Desc -lLLVMX86Disassembler -lLLVMX86Info -lLLVMX86Utils
> --no-whole-archive --soname libLLVM-3.5svn.so --no-undefined -lz -ltinfo
> -lm -lstdc++ -lm -lgcc_s -lc -lgcc_s
> /usr/lib/gcc/x86_64-linux-gnu/4.8/crtendS.o
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/crtn.o
>
> It doesn't seem to be linking the asan runtime which seems weird since I'm
> passing -faddress=sanitize.
>
>
> On Thu, Nov 21, 2013 at 5:24 AM, Alexander Potapenko <glider at google.com>wrote:
>
>> On Thu, Nov 21, 2013 at 6:18 AM, Keno Fischer <kfischer at csail.mit.edu>
>> wrote:
>> > Hello everybody,
>> >
>> > after moving from OS X to Linux build llvm with asan enabled
>> Sorry, I failed to parse this. You're compiling Clang on Linux, and
>> OSX is unrelated, right?
>> > (I also updated
>> > to trunk, but not sure if that's related). However, it's totally
>> possible
>> > that I missed a step that I took back when I set this up for me, so I
>> might
>> > be doing something very stupid. Anyway, I'm configuring LLVM with
>> >
>> > ../configure --prefix=/home/kfischer/julia/usr
>> --build=x86_64-pc-linux-gnu
>> > FC=gfortran
>> >
>> CC="/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts/Release+Asserts/bin/clang
>> > -fsanitize=address"
>> >
>> CXX="/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts/Release+Asserts/bin/clang++"
>> > -fsanitize=address --disable-profiling --enable-shared --enable-static
>> > --enable-targets=host --disable-bindings --disable-docs
>> --enable-assertions
>> > --enable-optimized --disable-threads
>> So you're building Clang with -fsanitize=address. Note: you won't be
>> able to build libsanitizer this way.
>>
>> > in a different directory (build_Release+Asserts+Sanitize). As you can
>> see
>> > I'm bootstrapping this through a different copy of clang I just built.
>> > However, now I'm getting tons of
>> > undefined reference to `__asan_report_store8'
>> > even though the command the failing command being invoked is
>> >
>> >
>> /home/kfischer/julia/deps/llvm-svn/build_Release+Asserts/Release+Asserts/bin/clang++
>> > -fsanitize=address   -O3 -Wl,-R -Wl,'$ORIGIN' -rdynamic
>> >
>> -L/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib
>> >
>> -L/home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib
>> > -shared -o
>> >
>> /home/kfischer/julia/deps/llvm-svn/build_Release+Asserts+Sanitize/Release+Asserts/lib/
>> libLLVM-3.5svn.so
>> > -Wl,--whole-archive -lLLVMAnalysis -lLLVMAsmParser -lLLVMAsmPrinter
>> > -lLLVMBitReader -lLLVMBitWriter -lLLVMCodeGen -lLLVMCore -lLLVMDebugInfo
>> > -lLLVMExecutionEngine -lLLVMInstCombine -lLLVMInstrumentation
>> > -lLLVMInterpreter -lLLVMipa -lLLVMipo -lLLVMIRReader -lLLVMLinker
>> -lLLVMLTO
>> > -lLLVMMC -lLLVMMCDisassembler -lLLVMMCJIT -lLLVMMCParser
>> -lLLVMObjCARCOpts
>> > -lLLVMObject -lLLVMOption -lLLVMRuntimeDyld -lLLVMScalarOpts
>> > -lLLVMSelectionDAG -lLLVMSupport -lLLVMTarget -lLLVMTransformUtils
>> > -lLLVMVectorize -lLLVMX86AsmParser -lLLVMX86AsmPrinter -lLLVMX86CodeGen
>> > -lLLVMX86Desc -lLLVMX86Disassembler -lLLVMX86Info -lLLVMX86Utils
>> > -Wl,--no-whole-archive -Wl,--soname,libLLVM-3.5svn.so-Wl,--no-undefined -lz
>> > -ltinfo -lm
>>
>> Can you please add -v to the command line to see the ld invocation line?
>> You'll need to locate the ASan runtime library and check whether it's
>> a 32-bit one and if __asan_report_store8 is present in its symbol
>> table.
>> > Am I doing something stupid?
>> > Thanks,
>> > Keno
>> >
>> >
>> > _______________________________________________
>> > LLVM Developers mailing list
>> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>> >
>>
>>
>>
>> --
>> Alexander Potapenko
>> Software Engineer
>> Google Moscow
>>
>
>
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