A little more detail on the error in question. This is a very obscure
error, so please bear with me.
>>/usr/bin/ld.gold: error: CMakeFiles/cmTC_81c99.dir/CheckSymbolExists.c.o:
failed to match split-stack sequence at section 4 offset 0
What's happening here is that the linker (ld.gold) is linking together two
object files, let's call them "a.o" and "b.o".
The linker detects that one of the objects (let's say "a.o") has a marker
indicating that it was compiled with the "-fsplit-stack" option. The second
object file "b.o" has no such marker (e.g. it apparently wasn't compiled
with -fsplit-stack).
In addition, the linker sees (from object file relocations) that a function
(let's call it AFunc) in a.o is making a call to BFunc in b.o. In such
instances the gold linker has a feature that will perform a fixup/rewrite
on the calling function to make sure that when the call takes place, the
stack is large enough (so that -split-stack will have the right effect).
To apply this fixup, the linker is looking for a specific prolog
instruction sequence-- when it doesn't find that sequence, it issues the
error.
In the previous LLVM bug I cited, the problem was with the C compiler -- it
was marking the object as split-stack, but not consistently emitting the
prolog sequence that the linker looks for.
Your compiler is an up-to-date version of GCC, however, so it's hard for me
to believe that the compiler is at fault.
[This is a lot of technical detail, sorry about that].
Do you think you could rerun the compile by hand and send me some of the
output (e.g. regenerate the file "CheckSymbolExists.c" as it appeared in
the cmake output log?
Thanks, Than
On Thu, Apr 30, 2020 at 4:39 PM Martins Eglitis <mart...@sitilge.id.lv>
wrote:
> Sorry, I should have mentioned that I am running a docker container based
> on the latest Ubuntu, and Ubuntu 18.04 as the host.
>
> On April 30, 2020 11:37:15 PM GMT+03:00, Martins Eglitis <
> mart...@sitilge.id.lv> wrote:
>>
>> Yes,
>>
>> cc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
>>
>>
>> On April 30, 2020 11:29:07 PM GMT+03:00, Than McIntosh <th...@google.com>
>> wrote:
>>>
>>> >>/usr/bin/ld.gold: error: CMakeFiles/cmTC_81c99.dir/CheckSymbolExists.c.o:
>>> failed to match split-stack sequence at section 4 offset 0
>>>
>>> OK, now I think we're getting somewhere, this looks suspicious. For
>>> reference, could you please send me the output of "/usr/bin/cc --version"?
>>>
>>> Thanks, Than
>>>
>>>
>>>
>>>
>>> On Thu, Apr 30, 2020 at 4:26 PM Martins Eglitis <mart...@sitilge.id.lv>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> There was something related in "CMakeError.log":
>>>>
>>>> Determining if the mmap exist failed with the following output:
>>>> Change Dir: /home/gopher/workarea/build-debug/CMakeFiles/CMakeTmp
>>>>
>>>> Run Build Command(s):/usr/bin/ninja cmTC_81c99 && [1/2] Building C object
>>>> CMakeFiles/cmTC_81c99.dir/CheckSymbolExists.c.o
>>>> CheckSymbolExists.c: In function 'main':
>>>> CheckSymbolExists.c:8:11: warning: ISO C forbids conversion of function
>>>> pointer to object pointer type [-Wpedantic]
>>>> 8 | return ((int*)(&mmap))[argc];
>>>> | ^
>>>> [2/2] Linking C executable cmTC_81c99
>>>> FAILED: cmTC_81c99
>>>> : && /usr/bin/cc -fPIC -Werror=date-time -Wall -Wextra
>>>> -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers
>>>> -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-comment
>>>> -fdiagnostics-color -ffunction-sections -fdata-sections -fuse-ld=gold
>>>> -fsplit-stack -fuse-ld=gold -Wl,-allow-shlib-undefined
>>>> CMakeFiles/cmTC_81c99.dir/CheckSymbolExists.c.o -o cmTC_81c99 -lm && :
>>>> /usr/bin/ld.gold: error: CMakeFiles/cmTC_81c99.dir/CheckSymbolExists.c.o:
>>>> failed to match split-stack sequence at section 4 offset 0
>>>> collect2: error: ld returned 1 exit status
>>>> ninja: build stopped: subcommand failed.
>>>>
>>>>
>>>> File
>>>> /home/gopher/workarea/build-debug/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
>>>> /* */
>>>> #include <sys/mman.h>
>>>>
>>>> int main(int argc, char** argv)
>>>> {
>>>> (void)argv;
>>>> #ifndef mmap
>>>> return ((int*)(&mmap))[argc];
>>>> #else
>>>> (void)argc;
>>>> return 0;
>>>> #endif
>>>> }
>>>>
>>>> On 2020-04-30 20:32, Than McIntosh wrote:
>>>>
>>>> Thanks for the email.
>>>>
>>>> Sorry for the delay in responding, this is a very busy time right now
>>>> for our team (release freeze is happening at the end of this week).
>>>>
>>>> Just in general, the gollvm build procedure uses "cmake", and as part
>>>> of this process cmake is running various tests to make sure that the C
>>>> compiler you're using works properly, and to detect whether the system you
>>>> are building on has the right header files, libraries, etc.
>>>>
>>>> Of particular concern is the cmake check for "mmap"-- the mmap()
>>>> routine is definitely available on Ubuntu, so it's puzzling that cmake
>>>> thinks it isn't available.
>>>>
>>>> One thing you might do: after the build fails, try looking at the
>>>> debris in the CMakeFiles dir:
>>>>
>>>> $ ls CMakeFiles
>>>> 3.13.4 cmake.check_cache feature_tests.bin src.c
>>>> 3.15.4 CMakeError.log feature_tests.c
>>>> TargetDirectories.txt
>>>> CheckIncludeFiles CMakeOutput.log feature_tests.cxx test.o
>>>> CheckTypeSize CMakeTmp simple.cc
>>>>
>>>> In that dir, look at "CMakeOutput.log" for the place where this test is
>>>> run:
>>>>
>>>> Look for a section that looks like this:
>>>>
>>>> Determining if the mmap exist passed with the following output:
>>>> Change Dir: /tmp/llvm-project/build-relwithdbg/CMakeFiles/CMakeTmp
>>>>
>>>> Run Build Command:"/usr/local/google/home/thanm/bin/ninja"
>>>> "cmTC_feb45"
>>>> [1/2] Building C object
>>>> CMakeFiles/cmTC_feb45.dir/CheckSymbolExists.c.o
>>>> CheckSymbolExists.c: In function ‘main’:
>>>> CheckSymbolExists.c:8:11: warning: ISO C forbids conversion of
>>>> function pointer to object pointer type [-Wpedantic]
>>>> return ((int*)(&mmap))[argc];
>>>> ^
>>>> [2/2] Linking C executable cmTC_feb45
>>>>
>>>> File
>>>> /tmp/llvm-project/build-relwithdbg/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
>>>> /* */
>>>> #include <sys/mman.h>
>>>>
>>>> int main(int argc, char** argv)
>>>> {
>>>> (void)argv;
>>>> #ifndef mmap
>>>> return ((int*)(&mmap))[argc];
>>>> #else
>>>> (void)argc;
>>>> return 0;
>>>> #endif
>>>> }
>>>>
>>>> Are there any clues there perhaps?
>>>>
>>>> Thanks, Than
>>>>
>>>>
>>>> On Thu, Apr 30, 2020 at 1:05 PM <siti...@gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I initially opened an issue, but was suggested to post to the mailing
>>>>> list instead: https://github.com/golang/go/issues/38728
>>>>>
>>>>> Build keeps failing when trying to build (Ubuntu Focal Fossa, amd64)
>>>>> from the latest commit to the master and following the build instructions.
>>>>> Has anyone succeeded to build gollvm recently? I am getting errors like
>>>>> this:
>>>>>
>>>>> -- Could NOT find LibXml2 (missing: LIBXML2_LIBRARY LIBXML2_INCLUDE_DIR)
>>>>> -- Native target architecture is X86
>>>>> -- Threads enabled.
>>>>> -- Doxygen disabled.
>>>>> -- Go bindings disabled.
>>>>> -- Ninja version: 1.10.0
>>>>> -- Could NOT find OCaml (missing: OCAMLFIND OCAML_VERSION
>>>>> OCAML_STDLIB_PATH)
>>>>> -- Could NOT find OCaml (missing: OCAMLFIND OCAML_VERSION
>>>>> OCAML_STDLIB_PATH)
>>>>> -- OCaml bindings disabled.
>>>>> -- LLVM host triple: x86_64-unknown-linux-gnu
>>>>> -- LLVM default target triple: x86_64-unknown-linux-gnu
>>>>> -- Building with -fPIC
>>>>> -- Constructing LLVMBuild project information
>>>>> -- Targeting AArch64
>>>>> -- Targeting AMDGPU
>>>>> -- Targeting ARM
>>>>> -- Targeting AVR
>>>>> -- Targeting BPF
>>>>> -- Targeting Hexagon
>>>>> -- Targeting Lanai
>>>>> -- Targeting Mips
>>>>> -- Targeting MSP430
>>>>> -- Targeting NVPTX
>>>>> -- Targeting PowerPC
>>>>> -- Targeting RISCV
>>>>> -- Targeting Sparc
>>>>> -- Targeting SystemZ
>>>>> -- Targeting WebAssembly
>>>>> -- Targeting X86
>>>>> -- Targeting XCore
>>>>> CMake Error at tools/gollvm/cmake/modules/AddGollvm.cmake:37 (message):
>>>>> C compiler does not support -fsplit-stack
>>>>> Call Stack (most recent call first):
>>>>> tools/gollvm/CMakeLists.txt:21 (include)
>>>>>
>>>>>
>>>>> -- starting libgo configuration.
>>>>> CMake Error at tools/gollvm/cmake/modules/LibbacktraceUtils.cmake:19
>>>>> (message):
>>>>> Support for mmap() is required -- setup failed.
>>>>> Call Stack (most recent call first):
>>>>> tools/gollvm/libgo/CMakeLists.txt:45 (setup_libbacktrace)
>>>>>
>>>>>
>>>>> CMake Error at tools/gollvm/cmake/modules/LibffiUtils.cmake:27 (message):
>>>>> Support for mmap() is required -- setup failed.
>>>>> Call Stack (most recent call first):
>>>>> tools/gollvm/libgo/CMakeLists.txt:49 (setup_libffi)
>>>>>
>>>>>
>>>>> -- Libgo: creating stdlib package targets
>>>>> -- Libgo: generating check targets
>>>>> -- libgo configuration complete.
>>>>> -- starting gotools configuration.
>>>>> -- gotools: generating check targets
>>>>> -- gotools configuration complete.
>>>>> -- Registering Bye as a pass plugin (static build: OFF)
>>>>> -- Failed to find LLVM FileCheck
>>>>> -- Version: 0.0.0
>>>>> -- Performing Test HAVE_GNU_POSIX_REGEX -- failed to compile
>>>>> -- Performing Test HAVE_POSIX_REGEX -- success
>>>>> -- Performing Test HAVE_STEADY_CLOCK -- success
>>>>> -- Configuring incomplete, errors occurred!
>>>>> See also "/home/gopher/workarea/build-debug/CMakeFiles/CMakeOutput.log".
>>>>> See also "/home/gopher/workarea/build-debug/CMakeFiles/CMakeError.log".
>>>>> ninja: error: loading 'build.ninja': No such file or directory
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> You received this message because you are subscribed to the Google
>>>>> Groups "golang-nuts" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>>> an email to golang-nuts+unsubscr...@googlegroups.com.
>>>>> To view this discussion on the web visit
>>>>> https://groups.google.com/d/msgid/golang-nuts/cdb72cf2-2fe2-4f44-87fb-5cc2058dd58a%40googlegroups.com
>>>>> <https://groups.google.com/d/msgid/golang-nuts/cdb72cf2-2fe2-4f44-87fb-5cc2058dd58a%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>> .
>>>>>
>>>> --
>>>> Best regards,
>>>> Martins Eglitis
>>>>
>>>>
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
>
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