gcc-8.0 error=class-memaccess compile failure due to memcpy in ./memtable/inlineskiplist.h #2705

grooverdan · 2017-08-09T00:17:15Z

This isn't occurring on the gcc-7-branch however the gcc master/trunk branch is enhancing its strictness

${CXX} --version
+ x86_64-pc-linux-gnu-g++ --version
x86_64-pc-linux-gnu-g++ (GCC) 8.0.0 20170808 (experimental)

x86_64-pc-linux-gnu-g++ -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native -std=c++11  -DROCKSDB_USE_RTTI -g -faligned-new -W -Wextra -Wall -Wsign-compare -Wshadow -Wno-unused-parameter -Werror -I. -I./include -std=c++11 -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native -std=c++11 -DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native -DOS_LINUX -fno-builtin-memcmp -DROCKSDB_FALLOCATE_PRESENT -DSNAPPY -DGFLAGS=gflags -DZLIB -DBZIP2 -DLZ4 -DZSTD -DNUMA -DTBB -DROCKSDB_MALLOC_USABLE_SIZE -DROCKSDB_PTHREAD_ADAPTIVE_MUTEX -DROCKSDB_BACKTRACE -DROCKSDB_RANGESYNC_PRESENT -DROCKSDB_SCHED_GETCPU_PRESENT -march=native  -DHAVE_SSE42 -DROCKSDB_SUPPORT_THREAD_LOCAL -DROCKSDB_JEMALLOC -DJEMALLOC_NO_DEMANGLE  -isystem ./third-party/gtest-1.7.0/fused-src -DSNAPPY=1 -DLZ4=1 -DZLIB=1 -DJEMALLOC=1 -DZSTD=1 -DNUMA=1 -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -c memtable/skiplistrep.cc -o memtable/skiplistrep.o 
In file included from memtable/skiplistrep.cc:6:0:
./memtable/inlineskiplist.h: In instantiation of 'void rocksdb::InlineSkipList::Node::StashHeight(int) [with Comparator = const rocksdb::MemTableRep::KeyComparator&]':
./memtable/inlineskiplist.h:599:3:   required from 'rocksdb::InlineSkipList::Node* rocksdb::InlineSkipList::AllocateNode(size_t, int) [with Comparator = const rocksdb::MemTableRep::KeyComparator&; size_t = long unsigned int]'
./memtable/inlineskiplist.h:561:25:   required from 'rocksdb::InlineSkipList::InlineSkipList(Comparator, rocksdb::Allocator*, int32_t, int32_t) [with Comparator = const rocksdb::MemTableRep::KeyComparator&; int32_t = int]'
memtable/skiplistrep.cc:28:28:   required from here
./memtable/inlineskiplist.h:281:11: error: 'void* memcpy(void*, const void*, size_t)' writing to an object of type 'struct std::atomic::Node*>' with no trivial copy-assignment [-Werror=class-memaccess]
     memcpy(&next_[0], &height, sizeof(int));
     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./memtable/inlineskiplist.h:47:0,
                 from memtable/skiplistrep.cc:6:
/compiler/include/c++/8.0.0/atomic:352:12: note: 'struct std::atomic::Node*>' declared here
     struct atomic<_Tp*>
            ^~~~~~~~~~~~
cc1plus: all warnings being treated as errors
Makefile:1731: recipe for target 'memtable/skiplistrep.o' failed
make: *** [memtable/skiplistrep.o] Error 1

yiwu-arbug · 2017-08-10T01:41:45Z

@grooverdan will replace &next_[0] with static_cast<void*>(&next_[0]) workaround the error? I don't have gcc8 at hand.

grooverdan · 2017-08-10T07:10:51Z

Sorry - wasn't sufficient. Didn't really have time to do much else about it today.

${CXX} --version
+ powerpc64le-unknown-linux-gnu-g++ --version
powerpc64le-unknown-linux-gnu-g++ (GCC) 8.0.0 20170809 (experimental)


powerpc64le-unknown-linux-gnu-g++ -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native  -DROCKSDB_USE_RTTI -g -faligned-new -W -Wextra -Wall -Wsign-compare -Wshadow -Wno-unused-parameter -Werror -I. -I./include -std=c++11 -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native -DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX -m64 -O3 -g -I /opt/ibm/java/include/ -mtune=native -DOS_LINUX -fno-builtin-memcmp -DROCKSDB_FALLOCATE_PRESENT -DSNAPPY -DGFLAGS=gflags -DZLIB -DBZIP2 -DLZ4 -DZSTD -DNUMA -DTBB -DROCKSDB_MALLOC_USABLE_SIZE -DROCKSDB_PTHREAD_ADAPTIVE_MUTEX -DROCKSDB_BACKTRACE -DROCKSDB_RANGESYNC_PRESENT -DROCKSDB_SCHED_GETCPU_PRESENT -mcpu=power8 -mtune=power8  -DROCKSDB_SUPPORT_THREAD_LOCAL -DROCKSDB_JEMALLOC -DJEMALLOC_NO_DEMANGLE  -isystem ./third-party/gtest-1.7.0/fused-src  -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -c memtable/skiplistrep.cc -o memtable/skiplistrep.o 
In file included from memtable/skiplistrep.cc:6:0:
./memtable/inlineskiplist.h: In instantiation of 'void rocksdb::InlineSkipList::Node::StashHeight(int) [with Comparator = const rocksdb::MemTableRep::KeyComparator&]':
./memtable/inlineskiplist.h:599:3:   required from 'rocksdb::InlineSkipList::Node* rocksdb::InlineSkipList::AllocateNode(size_t, int) [with Comparator = const rocksdb::MemTableRep::KeyComparator&; size_t = long unsigned int]'
./memtable/inlineskiplist.h:561:25:   required from 'rocksdb::InlineSkipList::InlineSkipList(Comparator, rocksdb::Allocator*, int32_t, int32_t) [with Comparator = const rocksdb::MemTableRep::KeyComparator&; int32_t = int]'
memtable/skiplistrep.cc:28:28:   required from here
./memtable/inlineskiplist.h:281:11: error: 'void* memcpy(void*, const void*, size_t)' writing to an object of type 'struct std::atomic::Node*>' with no trivial copy-assignment [-Werror=class-memaccess]
     memcpy(static_cast(&next_[0]), &height, sizeof(int));
     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./memtable/inlineskiplist.h:47:0,
                 from memtable/skiplistrep.cc:6:
/compiler/include/c++/8.0.0/atomic:352:12: note: 'struct std::atomic::Node*>' declared here
     struct atomic<_Tp*>
            ^~~~~~~~~~~~
cc1plus: all warnings being treated as errors

tamird · 2018-01-10T16:55:17Z

Since this writing there are more errors under gcc 8:

$ g++ --version
g++ (GCC) 8.0.0 20180108 (experimental)

/home/tduberstein/local/rocksdb/db/c.cc: In function ‘void rocksdb_writebatch_wi_iterate(rocksdb_writebatch_wi_t*, void*, void (*)(void*, const char*, size_t, const char*, size_t), void (*)(void*, const char*, size_t))’:
/home/tduberstein/local/rocksdb/db/c.cc:1664:5: error: conflicting C language linkage declaration ‘rocksdb_writebatch_wi_iterate(rocksdb_writebatch_wi_t*, void*, void (*)(void*, const char*, size_t, const char*, size_t), void (*)(void*, const char*, size_t))::H handler’ [-Werror]
   H handler;
     ^~~~~~~
/home/tduberstein/local/rocksdb/db/c.cc:1408:5: note: previous declaration ‘rocksdb_writebatch_iterate(rocksdb_writebatch_t*, void*, void (*)(void*, const char*, size_t, const char*, size_t), void (*)(void*, const char*, size_t))::H handler’
   H handler;
     ^~~~~~~
/home/tduberstein/local/rocksdb/db/c.cc: In function ‘rocksdb_slicetransform_t* rocksdb_slicetransform_create_fixed_prefix(size_t)’:
/home/tduberstein/local/rocksdb/db/c.cc:3126:12: error: conflicting C language linkage declaration ‘rocksdb_slicetransform_create_fixed_prefix(size_t)::Wrapper* wrapper’ [-Werror]
   Wrapper* wrapper = new Wrapper;
            ^~~~~~~
/home/tduberstein/local/rocksdb/db/c.cc:2680:12: note: previous declaration ‘rocksdb_filterpolicy_create_bloom_format(int, bool)::Wrapper* wrapper’
   Wrapper* wrapper = new Wrapper;
            ^~~~~~~
/home/tduberstein/local/rocksdb/db/c.cc: In function ‘rocksdb_slicetransform_t* rocksdb_slicetransform_create_noop()’:
/home/tduberstein/local/rocksdb/db/c.cc:3147:12: error: conflicting C language linkage declaration ‘rocksdb_slicetransform_create_noop()::Wrapper* wrapper’ [-Werror]
   Wrapper* wrapper = new Wrapper;
            ^~~~~~~
/home/tduberstein/local/rocksdb/db/c.cc:2680:12: note: previous declaration ‘rocksdb_filterpolicy_create_bloom_format(int, bool)::Wrapper* wrapper’
   Wrapper* wrapper = new Wrapper;
            ^~~~~~~
cc1plus: all warnings being treated as errors

siying · 2018-01-10T23:03:03Z

@grooverdan @tamird feel free to send pull requests for those fixes. As @yiwu-arbug said, we don't have such environment to fix it. As long as your PR looks reasonable, we'll just merge it.

tamird · 2018-04-23T15:28:54Z

This was fixed in #3736.

grooverdan · 2018-04-23T23:08:05Z

thanks @inikep

jonhoo · 2018-05-16T16:24:49Z

master still does not compile with gcc8 for me on Arch Linux:

  CC       shared-objects/util/status_message.o
util/status.cc: In static member function ‘static const char* rocksdb::Status::CopyState(const char*)’:
util/status.cc:28:15: error: ‘char* strncpy(char*, const char*, size_t)’ output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
   std::strncpy(result, state, cch - 1);
   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
util/status.cc:19:18: note: length computed here
       std::strlen(state) + 1; // +1 for the null terminator
       ~~~~~~~~~~~^~~~~~~
cc1plus: all warnings being treated as errors
make: *** [Makefile:645: shared-objects/util/status.o] Error 1

This is with 8.1 though:

$ gcc --version
gcc (GCC) 8.1.0

ajkr · 2018-05-18T02:10:46Z

@jonhoo are you interested in trying to fix it? We don't have access to that platform

jonhoo · 2018-05-18T02:15:40Z

@ajkr this should happen with any gcc8.1 install — I don't think it's Arch Linux specific. I don't have any experience with the codebase so don't think I'm the right person to write a patch; I was just trying to compile rocksdb as a dependency :)

grooverdan · 2018-05-18T03:51:33Z

If you don't like the ugly hack of a workaround I won't be offended.

tested in gcc from fc28.

$ gcc --version
gcc (GCC) 8.1.1 20180502 (Red Hat 8.1.1-1)

might be https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944

inikep · 2018-05-18T12:42:07Z

I can't reproduce you error with Ubuntu 16.04 and:

gcc version 8.1.0 (Ubuntu 8.1.0-1ubuntu3~16.04.york0)

vedatech · 2018-06-13T10:48:01Z

@inikep, try in Docker container (similar error)

FROM rikorose/gcc-cmake:gcc-8
...

grooverdan · 2018-06-14T00:20:32Z

#3433 has on other gcc8 fixes too.

ryanwwest · 2018-06-14T17:54:35Z

We depend on rocksdb too but it looks like I'm getting a similar error as @jonhoo when trying to run make shared_lib:

  CC       shared-objects/util/status.o
util/status.cc: In static member function ‘static const char* rocksdb::Status::CopyState(const char*)’:                                                             
util/status.cc:28:15: error: ‘char* strncpy(char*, const char*, size_t)’ output truncated before terminating nul copying as many bytes from a string as its length [-
Werror=stringop-truncation]
   std::strncpy(result, state, cch - 1);
   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
util/status.cc:19:18: note: length computed here
       std::strlen(state) + 1; // +1 for the null terminator
       ~~~~~~~~~~~^~~~~~~

I'm on Fedora Linux using gcc 8.1.1.

Summary: Various rearrangements of the cch maths failed or replacing = '\0' with memset failed to convince the compiler it was nul terminated. So took the perverse option of changing strncpy to strcpy. Return null if memory couldn't be allocated. util/status.cc: In static member function ‘static const char* rocksdb::Status::CopyState(const char*)’: util/status.cc:28:15: error: ‘char* strncpy(char*, const char*, size_t)’ output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation] std::strncpy(result, state, cch - 1); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~ util/status.cc:19:18: note: length computed here std::strlen(state) + 1; // +1 for the null terminator ~~~~~~~~~~~^~~~~~~ cc1plus: all warnings being treated as errors make: *** [Makefile:645: shared-objects/util/status.o] Error 1 closes facebook#2705 Closes facebook#3870 Differential Revision: D8594114 Pulled By: anand1976 fbshipit-source-id: ab20f3a456a711e4d29144ebe630e4fe3c99ec25

tamird mentioned this issue Jan 26, 2018

gccgo: SIGSEGV during cgo call golang/go#23393

Closed

BusyJay mentioned this issue May 10, 2018

Fails to compile on fedora 28 tikv/rust-rocksdb#206

Closed

ajkr added the up-for-grabs Up for grabs label May 18, 2018

grooverdan mentioned this issue May 18, 2018

Remove bogus gcc-8.1 warning #3870

Closed

facebook-github-bot closed this as completed in e5ae1bb Jun 27, 2018

rleungx mentioned this issue Jan 4, 2019

make install-rocksdb-ull failed with gcc 8.x lni/dragonboat#7

Closed

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gcc-8.0 error=class-memaccess compile failure due to memcpy in ./memtable/inlineskiplist.h #2705

gcc-8.0 error=class-memaccess compile failure due to memcpy in ./memtable/inlineskiplist.h #2705

grooverdan commented Aug 9, 2017

yiwu-arbug commented Aug 10, 2017 •

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grooverdan commented Aug 10, 2017

tamird commented Jan 10, 2018

siying commented Jan 10, 2018

tamird commented Apr 23, 2018

grooverdan commented Apr 23, 2018

jonhoo commented May 16, 2018 •

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ajkr commented May 18, 2018

jonhoo commented May 18, 2018

grooverdan commented May 18, 2018

inikep commented May 18, 2018

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grooverdan commented Jun 14, 2018

ryanwwest commented Jun 14, 2018 •

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gcc-8.0 error=class-memaccess compile failure due to memcpy in ./memtable/inlineskiplist.h #2705

gcc-8.0 error=class-memaccess compile failure due to memcpy in ./memtable/inlineskiplist.h #2705

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grooverdan commented Aug 9, 2017

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