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

Tue Jul 16 04:46:39 PDT 2019

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<mailto: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<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<mailto:ruiu at google.com>>
Cc: llvm-dev at lists.llvm.org<mailto: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

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