[llvm-dev] lld-link crash when linking intrinsics lib

Wed Feb 27 16:29:01 PST 2019

On Wed, Feb 27, 2019 at 4:16 PM Rui Ueyama <ruiu at google.com> wrote:

> On Wed, Feb 27, 2019 at 4:05 PM Peter Collingbourne <pcc at google.com>
> wrote:
>
>> Hmm, you might need something like the ELF linker's r338434/r339301 in
>> the COFF linker.
>>
>
> Are you going to do that? If we need to port it in a straightforward way,
> I think I can do that, though.
>

I wasn't going to. It probably shouldn't be too hard, but one thing to keep
in mind is that the names in RuntimeLibcalls.def are unmangled (i.e. no '_'
prepended on Win/i386), so on that target we'd probably need to check both
the mangled and unmangled names.

Peter

>
> Peter
>>
>> On Wed, Feb 27, 2019 at 4:01 PM Rui Ueyama <ruiu at google.com> wrote:
>>
>>> +Peter Collingbourne <pcc at chromium.org>
>>>
>>> LTO is used in this test case, and one source file defines its own
>>> `memset` function while the other file uses llvm.memset. Looks like LTO is
>>> confused by the user-defined memset. Could you take a look?
>>>
>>> Steven,
>>>
>>> Do you need to use LTO? I thought that LTO is a workaround to not
>>> produce an object file that cannot be handled by your ELF-to-COFF
>>> translation tool. If you are now doing a regular cross build, I guess you
>>> can remove -flto.
>>>
>>> On Wed, Feb 27, 2019 at 3:00 PM Rui Ueyama <ruiu at google.com> wrote:
>>>
>>>> Hi Steven,
>>>>
>>>> I confirmed that lld-link crashes with these inputs. That shouldn't
>>>> happen. I'll debug this and get back to you. Thank you for reporting.
>>>>
>>>> On Tue, Feb 26, 2019 at 8:20 PM Shi, Steven <steven.shi at intel.com>
>>>> wrote:
>>>>
>>>>> Hello Rui,
>>>>>
>>>>> I met couples of lld-link crash when enable the clang-cl + lld-link
>>>>> build toolchain for Uefi firmware. Below is a simplified example (main.c
>>>>> and intrinsics.c).
>>>>>
>>>>> Uefi firmware is self-contained and doesn’t depend on the compiler
>>>>> intrinsics implementation, so we have our own intrinsics lib. It is weird
>>>>> that if I don’t use the llvm-lib but directly “lld-link /NODEFAULTLIB
>>>>> /ENTRY:main  main.obj intrinsics.obj”, the below example can pass link.
>>>>> Please advise what’s wrong in this example.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> $ cat main.c
>>>>>
>>>>> typedef struct {
>>>>>
>>>>>   struct MAP_LIST {
>>>>>
>>>>>     unsigned long long  VirtualAddress;
>>>>>
>>>>>     void              *MapCookie;
>>>>>
>>>>>   } MapList[100];
>>>>>
>>>>> } SNP_DRIVER;
>>>>>
>>>>> SNP_DRIVER snp_instance;
>>>>>
>>>>> int main()
>>>>>
>>>>> {
>>>>>
>>>>>   SNP_DRIVER  *Snp;
>>>>>
>>>>>   Snp = &snp_instance;
>>>>>
>>>>>   for (int Index = 0; Index < 100; Index++) {
>>>>>
>>>>>     Snp->MapList[Index].VirtualAddress = 0;
>>>>>
>>>>>     Snp->MapList[Index].MapCookie      = 0;
>>>>>
>>>>>   }
>>>>>
>>>>>   return 0;
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>>
>>>>> $ cat intrinsics.c
>>>>>
>>>>> void * memset (void *dest, int ch, size_t count)
>>>>>
>>>>> {
>>>>>
>>>>>   volatile char  *Pointer;
>>>>>
>>>>>   Pointer = (char *)dest;
>>>>>
>>>>>   while (count-- != 0) {
>>>>>
>>>>>     *(Pointer++) = (char)ch;
>>>>>
>>>>>   }
>>>>>
>>>>>   return dest;
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/clang-cl" /Fomain.obj /c
>>>>> --target=x86_64-pc-win32-coff -m64 /O1b2s -flto main.c
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/clang-cl" /Fointrinsics.obj /c
>>>>> --target=x86_64-pc-win32-coff -m64 /O1b2s -flto intrinsics.c
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/llvm-lib" /OUT:intrinsics.lib
>>>>> intrinsics.obj
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/lld-link" /NODEFAULTLIB
>>>>> /ENTRY:main  main.obj intrinsics.lib
>>>>>
>>>>> Stack dump:
>>>>>
>>>>> 0.      Program arguments:
>>>>> /home/jshi19/llvm/releaseinstall/bin/lld-link /NODEFAULTLIB /ENTRY:main
>>>>> main.obj intrinsics.lib
>>>>>
>>>>> #0 0x0000559a34ba5e4a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x272e4a)
>>>>>
>>>>> #1 0x0000559a34ba3d14 llvm::sys::RunSignalHandlers()
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x270d14)
>>>>>
>>>>> #2 0x0000559a34ba3e52 SignalHandler(int)
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x270e52)
>>>>>
>>>>> #3 0x00007f896c8ea890 __restore_rt
>>>>> (/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
>>>>>
>>>>> #4 0x0000559a34c11325
>>>>> lld::coff::markLive(llvm::ArrayRef<lld::coff::Chunk*>)
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x2de325)
>>>>>
>>>>> #5 0x0000559a34bf0220
>>>>> lld::coff::LinkerDriver::link(llvm::ArrayRef<char const*>)
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x2bd220)
>>>>>
>>>>> #6 0x0000559a34bf0478 lld::coff::link(llvm::ArrayRef<char const*>,
>>>>> bool, llvm::raw_ostream&)
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x2bd478)
>>>>>
>>>>> #7 0x0000559a34b2a300 main
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x1f7300)
>>>>>
>>>>> #8 0x00007f896b3c1b97 __libc_start_main
>>>>> /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
>>>>>
>>>>> #9 0x0000559a34b8c27a _start
>>>>> (/home/jshi19/llvm/releaseinstall/bin/lld-link+0x25927a)
>>>>>
>>>>> Segmentation fault (core dumped)
>>>>>
>>>>>
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/clang-cl" --version
>>>>>
>>>>> clang version 9.0.0 (https://github.com/llvm-mirror/clang.git
>>>>> 1f02068469ff18f5fc5728cafe9d96ee5f66c5b9) (
>>>>> https://github.com/llvm-project/llvm.git
>>>>> 330395ea4fce35b019b33797ff751be029a1f866)
>>>>>
>>>>> Target: x86_64-pc-windows-msvc
>>>>>
>>>>> Thread model: posix
>>>>>
>>>>> InstalledDir: /home/jshi19/llvm/releaseinstall/bin
>>>>>
>>>>>
>>>>>
>>>>> $ "/home/jshi19/llvm/releaseinstall/bin/lld-link" --version
>>>>>
>>>>> LLD 9.0.0 (https://github.com/llvm-mirror/lld.git
>>>>> aa7adc0ec804b689771f11d52e39f83a16378f5f)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Thanks
>>>>>
>>>>>
>>>>>
>>>>> *Steven Shi*
>>>>>
>>>>> *Intel\SSG\FID\Firmware Infrastructure*
>>>>>
>>>>>
>>>>>
>>>>
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