[llvm-dev] lld-link crash when build openssl with LTO

Tue Jul 16 05:30:40 PDT 2019

Teresa,

It looks like even if we compile source files with `-fno-builtin` and one
of the source files have a definition of `memcpy`, LTO uses the builtin
`memcpy` instead of a user-supplied one. Is this an intended behavior?

On Tue, Jul 16, 2019 at 9:09 PM Rui Ueyama <ruiu at google.com> wrote:

> Yeah, it crashes indeed. I can reproduce the problem locally. Let me see
> what is going on.
>
> On Tue, Jul 16, 2019 at 9:00 PM Shi, Steven <steven.shi at intel.com> wrote:
>
>> In my previous test case, after add the `-fno-builtin` to clang then
>> build, the lld-link still has same crash as below:
>>
>>
>>
>> $ make
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -fno-builtin -c -o main.obj  main.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -fno-builtin -c -o memcpy.obj  memcpy.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:main.lib main.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:memcpy.lib memcpy.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link" /OUT:f.dll
>> /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint  main.lib  memcpy.lib
>>
>> Stack dump:
>>
>> 0.      Program arguments:
>> /home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link /OUT:f.dll
>> /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint main.lib memcpy.lib
>>
>> #0 0x000056348d5c185a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:498:0
>>
>> #1 0x000056348d5bf684 llvm::sys::RunSignalHandlers()
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Signals.cpp:68:0
>>
>> #2 0x000056348d5bf7c2 SignalHandler(int)
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:357:0
>>
>> #3 0x00007f200467a890 __restore_rt
>> (/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
>>
>> #4 0x000056348d614025 lld::coff::DefinedRegular::getChunk() const
>> /home/jshi19/llvm/llvm-project/lld/COFF/Symbols.h:176:0
>>
>> #5 0x000056348d614025 operator()
>> /home/jshi19/llvm/llvm-project/lld/COFF/MarkLive.cpp:46:0
>>
>> #6 0x000056348d614025
>> lld::coff::markLive(llvm::ArrayRef<lld::coff::Chunk*>)
>> /home/jshi19/llvm/llvm-project/lld/COFF/MarkLive.cpp:55:0
>>
>> #7 0x000056348d5f363e std::vector<lld::coff::Chunk*,
>> std::allocator<lld::coff::Chunk*> >::~vector()
>> /usr/include/c++/7/bits/stl_vector.h:434:0
>>
>> #8 0x000056348d5f363e lld::coff::LinkerDriver::link(llvm::ArrayRef<char
>> const*>) /home/jshi19/llvm/llvm-project/lld/COFF/Driver.cpp:1840:0
>>
>> #9 0x000056348d5f3d08 lld::coff::link(llvm::ArrayRef<char const*>, bool,
>> llvm::raw_ostream&) /home/jshi19/llvm/llvm-project/lld/COFF/Driver.cpp:78:0
>>
>> #10 0x000056348d536044 main
>> /home/jshi19/llvm/llvm-project/lld/tools/lld/lld.cpp:155:0
>>
>> #11 0x00007f2003151b97 __libc_start_main
>> /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
>>
>> #12 0x000056348d5915ba _start
>> (/home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link+0x25a5ba)
>>
>> Segmentation fault (core dumped)
>>
>> makefile:9: recipe for target 'build' failed
>>
>> make: *** [build] Error 139
>>
>>
>>
>> Thanks
>>
>> Steven
>>
>>
>>
>> *From:* Rui Ueyama [mailto:ruiu at google.com]
>> *Sent:* Tuesday, July 16, 2019 7:53 PM
>> *To:* Shi, Steven <steven.shi at intel.com>
>> *Cc:* llvm-dev at lists.llvm.org
>> *Subject:* Re: lld-link crash when build openssl with LTO
>>
>>
>>
>> lld should not crash in this case (so that's a bug that needs fixing),
>> but setting it aside, did you try adding `-fno-builtin` to clang so that
>> clang doesn't handle `memcpy` as a built-in function?
>>
>>
>>
>> On Tue, Jul 16, 2019 at 8:46 PM Shi, Steven <steven.shi at intel.com> wrote:
>>
>> Hi Rui,
>>
>> For the test case in my previous email,  if I change the `memcpy` to
>> `foobar` in memcpy.c, the lld-link report linking error that it cannot find
>> the _memcpy symbol as below. In uefi firmware, we have to explicitly
>> implement these compiler intrinsic functions by ourselves.
>>
>>
>>
>>
>>
>> jshi19 at ub2-uefi-b01:~/llvm/wrongcode/lld-link3$ make
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -c -o main.obj  main.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -c -o memcpy.obj  memcpy.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:main.lib main.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:memcpy.lib memcpy.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link" /OUT:f.dll
>> /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint  main.lib  memcpy.lib
>>
>> lld-link: error: undefined symbol: _memcpy
>>
>> >>> referenced by lto.tmp:(_TlsDriverEntryPoint)
>>
>> makefile:9: recipe for target 'build' failed
>>
>> make: *** [build] Error 1
>>
>>
>>
>> Thanks
>>
>> Steven
>>
>>
>>
>> *From:* Rui Ueyama [mailto:ruiu at google.com]
>> *Sent:* Tuesday, July 16, 2019 6:30 PM
>> *To:* Shi, Steven <steven.shi at intel.com>
>> *Cc:* llvm-dev at lists.llvm.org
>> *Subject:* Re: lld-link crash when build openssl with LTO
>>
>>
>>
>> Hi Steven,
>>
>>
>>
>> One thing I noticed is that you are defining `memcpy`, which clang has an
>> intrinsic with the same name. Can you try renaming it to a random name,
>> like `foobar`, to see if the problem still exists?
>>
>>
>>
>> On Tue, Jul 16, 2019 at 10:10 AM Shi, Steven <steven.shi at intel.com>
>> wrote:
>>
>> I’ve submitted a BZ for this issue as below:
>>
>>
>>
>> Bug 42626 - lld-link crash when build openssl with LTO
>>
>> https://bugs.llvm.org/show_bug.cgi?id=42626
>>
>>
>>
>>
>>
>> Thanks
>>
>> Steven
>>
>>
>>
>> *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of *Shi,
>> Steven via llvm-dev
>> *Sent:* Monday, July 15, 2019 4:40 PM
>> *To:* 'Rui Ueyama' <ruiu at google.com>
>> *Cc:* llvm-dev at lists.llvm.org
>> *Subject:* [llvm-dev] lld-link crash when build openssl with LTO
>>
>>
>>
>> Hi Rui,
>>
>> We met a lld-link crash problem when build 32bits openssl1.0 with LTO in
>> uefi firmware. We narrow down and figure out a simple test case to
>> reproduce this problem as blow. Please advise. Thank you!
>>
>>
>>
>> $ cat main.c
>>
>> void TlsDriverEntryPoint ()
>>
>> {
>>
>>   unsigned char *ret = 0;
>>
>>   const unsigned char cryptopro_ext[17] = {0x00,0x00,0x00,0x00,
>> 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01};
>>
>>   int length =17;
>>
>>   const char *Source;
>>
>>   Source  = (void*)cryptopro_ext;
>>
>>   while (length--) {
>>
>>     *(ret++) = *(Source++);
>>
>>   }
>>
>> }
>>
>>
>>
>> $ cat memcpy.c
>>
>> typedef unsigned int size_t;
>>
>> void *memcpy(void *dest, const void *src, size_t n)
>>
>> {
>>
>>   return 0;
>>
>> }
>>
>>
>>
>> $ cat makefile
>>
>> CC_FLAGS=  -Oz -flto -target i686-unknown-windows
>>
>> CC = /home/jshi19/llvm/llvm-project/releaseinstall/bin/clang
>>
>> DLINK_FLAGS = /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint
>>
>> DLINK = /home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link
>>
>> SLINK_FLAGS =
>>
>> SLINK = /home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib
>>
>>
>>
>> build:
>>
>>         "$(CC)" $(CC_FLAGS) -c -o main.obj  main.c
>>
>>         "$(CC)" $(CC_FLAGS) -c -o memcpy.obj  memcpy.c
>>
>>         "$(SLINK)" $(SLINK_FLAGS) /OUT:main.lib main.obj
>>
>>         "$(SLINK)" $(SLINK_FLAGS) /OUT:memcpy.lib memcpy.obj
>>
>>         "$(DLINK)" /OUT:f.dll $(DLINK_FLAGS) main.lib  memcpy.lib
>>
>>
>>
>> $ make
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -c -o main.obj  main.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/clang" -Oz -flto
>> -target i686-unknown-windows -c -o memcpy.obj  memcpy.c
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:main.lib main.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/llvm-lib"
>> /OUT:memcpy.lib memcpy.obj
>>
>> "/home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link" /OUT:f.dll
>> /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint  main.lib  memcpy.lib
>>
>> Stack dump:
>>
>> 0.      Program arguments:
>> /home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link /OUT:f.dll
>> /MACHINE:X86 /DLL /ENTRY:TlsDriverEntryPoint main.lib memcpy.lib
>>
>> #0 0x000055f11ed8585a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:498:0
>>
>> #1 0x000055f11ed83684 llvm::sys::RunSignalHandlers()
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Signals.cpp:68:0
>>
>> #2 0x000055f11ed837c2 SignalHandler(int)
>> /home/jshi19/llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:357:0
>>
>> #3 0x00007f172a5f2890 __restore_rt
>> (/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
>>
>> #4 0x000055f11edd8025 lld::coff::DefinedRegular::getChunk() const
>> /home/jshi19/llvm/llvm-project/lld/COFF/Symbols.h:176:0
>>
>> #5 0x000055f11edd8025 operator()
>> /home/jshi19/llvm/llvm-project/lld/COFF/MarkLive.cpp:46:0
>>
>> #6 0x000055f11edd8025
>> lld::coff::markLive(llvm::ArrayRef<lld::coff::Chunk*>)
>> /home/jshi19/llvm/llvm-project/lld/COFF/MarkLive.cpp:55:0
>>
>> #7 0x000055f11edb763e std::vector<lld::coff::Chunk*,
>> std::allocator<lld::coff::Chunk*> >::~vector()
>> /usr/include/c++/7/bits/stl_vector.h:434:0
>>
>> #8 0x000055f11edb763e lld::coff::LinkerDriver::link(llvm::ArrayRef<char
>> const*>) /home/jshi19/llvm/llvm-project/lld/COFF/Driver.cpp:1840:0
>>
>> #9 0x000055f11edb7d08 lld::coff::link(llvm::ArrayRef<char const*>, bool,
>> llvm::raw_ostream&) /home/jshi19/llvm/llvm-project/lld/COFF/Driver.cpp:78:0
>>
>> #10 0x000055f11ecfa044 main
>> /home/jshi19/llvm/llvm-project/lld/tools/lld/lld.cpp:155:0
>>
>> #11 0x00007f17290c9b97 __libc_start_main
>> /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
>>
>> #12 0x000055f11ed555ba _start
>> (/home/jshi19/llvm/llvm-project/releaseinstall/bin/lld-link+0x25a5ba)
>>
>> Segmentation fault (core dumped)
>>
>> makefile:12: recipe for target 'build' failed
>>
>> make: *** [build] Error 139
>>
>>
>>
>>
>>
>> Steven
>>
>> Thanks
>>
>>
>>
>>
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190716/d538875f/attachment.html>