use c++14

[jsteemann]

Experimental move to C++14
This is a search&replace solution for moving to C++14. It's possible that this does not cover all places in the code that need adjustment.

[jsteemann]

Running the AQL tests shows that it gets stuck somewhere in jemalloc:

$ scripts/unittest shell_server_aql
...

#0  __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x00007f91fe51419d in __GI___pthread_mutex_lock (mutex=mutex@entry=0x7f91eeb2b9d0) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005601a3fc60dd in malloc_mutex_lock_final (mutex=0x7f91eeb2b990) at include/jemalloc/internal/mutex.h:141
#3  je_malloc_mutex_lock_slow (mutex=mutex@entry=0x7f91eeb2b990) at src/mutex.c:83
#4  0x00005601a3fd2b68 in malloc_mutex_lock (mutex=0x7f91eeb2b990, tsdn=<optimized out>) at include/jemalloc/internal/mutex.h:205
#5  je_tcache_bin_flush_small (tsd=0x7f91ce2fce38, tcache=<optimized out>, tbin=<optimized out>, binind=1, rem=16) at src/tcache.c:134
#6  0x00005601a3fd3cbe in je_tcache_event_hard (tsd=<optimized out>, tcache=0x7f91ce2fcff0) at src/tcache.c:54
#7  0x00005601a278818f in __gnu_cxx::new_allocator<std::vector<unsigned long, std::allocator<unsigned long> > >::deallocate (
    this=0x7f91ce2f8d20, __p=<optimized out>) at /usr/include/c++/7/ext/new_allocator.h:125
#8  std::allocator_traits<std::allocator<std::vector<unsigned long, std::allocator<unsigned long> > > >::deallocate (__a=..., 
    __n=<optimized out>, __p=<optimized out>) at /usr/include/c++/7/bits/alloc_traits.h:462
#9  std::_Vector_base<std::vector<unsigned long, std::allocator<unsigned long> >, std::allocator<std::vector<unsigned long, std::allocator<unsigned long> > > >::_M_deallocate (this=0x7f91ce2f8d20, __n=<optimized out>, __p=<optimized out>)
    at /usr/include/c++/7/bits/stl_vector.h:180
#10 std::_Vector_base<std::vector<unsigned long, std::allocator<unsigned long> >, std::allocator<std::vector<unsigned long, std::allocator<unsigned long> > > >::~_Vector_base (this=0x7f91ce2f8d20, __in_chrg=<optimized out>) at /usr/include/c++/7/bits/stl_vector.h:162
#11 std::vector<std::vector<unsigned long, std::allocator<unsigned long> >, std::allocator<std::vector<unsigned long, std::allocator<unsigned long> > > >::~vector (this=0x7f91ce2f8d20, __in_chrg=<optimized out>) at /usr/include/c++/7/bits/stl_vector.h:435
#12 arangodb::velocypack::Builder::~Builder (this=0x7f91ce2f8ce0, __in_chrg=<optimized out>)
    at 3rdParty/velocypack/include/velocypack/Builder.h:182
#13 0x00005601a2a8ae82 in InsertVocbaseCol (isolate=<optimized out>, isolate@entry=0x7f91f5c6e100, args=..., 
    attachment=<optimized out>, attachment@entry=0x0) at arangod/V8Server/v8-collection.cpp:2225
#14 0x00005601a2a8b7f0 in JS_InsertVocbaseCol (args=...) at arangod/V8Server/v8-collection.cpp:2313

[dothebart]

when you change things in V8 please remember to also apply them in https://github.com/arangodb-helper/v8/tree/arangodb/3.3

[dothebart]

On cupertino (mac) the only thing I find in c++ --help is: -fsized-deallocation Enable C++14 sized global deallocation functions

[jsteemann]

@dothebart : this PR is supposed to be a test for whether compilation and tests work at all with C++14, and what changes will be required for it. If everyhing works and we are all happy with it, we can actually make changes in other repositories that we rely upon and perform the switchover.

[gnusi]

Is that somehow related?
redis/redis#3799
jemalloc/jemalloc#585
which version we use?

[jsteemann]

@gnusi : Probably it's unrelated. We have not changed out version of jemalloc (5.0.1) but just told the compiler to use -std=c++14 instead of -std=c++11. We are also not using libunwind.

[jsteemann]

closing as obsoleted