The tests currently issue a warning that
"warning: -fassociative-math disabled; other options take precedence"
The associative math optimization is turned on indirectly by -Ofast.
Apparently, the optimization is forced to be disabled, while compiling
test harnesses generated by Google Test framework.
Unfortunately, there is no -Wno-error=* flag to disable this warning
(see gcc --help=warnings).
An alternative to this patch is to disable the optimization explicitly
with -fno-associative-math, but that seems worse.
Another alternative is to not pass -Ofast for tests build, but we
want the tests to be built with exact same optimization flags as
the code being tested, otherwise the value of the tests is diminished.
Another alternative is to remove -Werror from the entire build, but
it's good to include that flag to preclude people leaving warnings.
A note regarding implementation of not passing -Werror for tests:
I considered filtering out -Werror from CMAKE_{C,CXX}_FLAGS but
that seems to be worse because it's surprizing behavior, to those
reading the code that adds -Werror. It is better to add it for
when it is used and not added otherwise. I also considered relying
on order, adding -Werror after inluding 'tests' subdir, but before
including the other subdirs, but that also seems cryptic to the
reader. So, I settled with the current solution, of explicitly
setting CMAKE_{C,CXX}_FLAGS to different values before including the
respective subdir.
Testing done: compared compiler invocation for non-tests source files
using `make VERBOSE=1` with and without this commit: the only difference
is the position of -Werror. So, this commit doesn't change the binary.
f07f120 cmake: don't try to link with atomic on Apple (redfish)
19349d7 cmake: ARM: clang: make warning non-fatal: inline asm (redfish)
f3e09f3 cmake: link with -latomic for clang (redfish)
f4b35ae cmake: include -ldl via cmake built-in var (redfish)
fa85cd8 common: stack trace: make clang happy with func ptrs (redfish)
4dce26b cmake: do not pass -stdlib=c++ to clang >=3.7 (redfish)
78cc10f daemon: fix ban seconds being misinterpreted as absolute (moneromooo-monero)
34ecfdb rpc: fix get_bans and set_bans RPC names, they were missing a _ (moneromooo-monero)
Signing is done using the spend key, since the view key may
be shared. This could be extended later, to let the user choose
which key (even a per tx key).
simplewallet's sign/verify API uses a file. The RPC uses a
string (simplewallet can't easily do strings since commands
receive a tokenized set of arguments).
otherwise clang build fails with
../cryptonote_core/libcryptonote_core.a(miner.cpp.o): In function
`std::__atomic_base<unsigned long long>::load(std::memory_order) const':
/usr/bin/../lib/gcc/i686-pc-linux-gnu/6.1.1/../../../../include/c++/6.1.1/bits/atomic_base.h:396:
undefined reference to `__atomic_load_8'
This has no effect on the gcc build.
The one strange thing is that test code like
std::atomic<int> x;
int main() { return x; }
compiles and links without errors with clang, without -latomic. This
alone would suggest that this patch is unnecessary, but that is not the
case. It's not clear exactly why, though. The bitmonero code is
including the same header, but it must be doing something more complex
than in this test code snippet that causes the failure at link time
pasted above. In any case, passing -latomic fixes the problem and
seems safe.
.
This does two things:
1. fixes clang build, which otherwise errors with undefined symbol
'dlsym'.
2. simplifies the cmake script, delegating to cmake to figure
out platform-specific flags for linking against the dl library.
Tested that it builds with:
gcc 6.1.1, STATIC=OFF,i686
gcc 6.1.1, STATIC=OFF,armv7h
clang 3.8, STATIC=OFF,i686
clang 3.8, STATIC=OFF,armv7h
gcc 6.1.1, STATIC=ON,i686
clang 3.8, STATIC=ON,i686
Also tested that stack trace is generated fine on exception on:
i686, gcc 6.1.1, STATIC=OFF
(didn't bother testing all the other platforms/configs)
This should fix the build problem on OSX (#871, #901), but
I don't have OSX, so I could only test Clang on Linux.
Tested on Linux (Arch) with clang 3.7 and 3.8 i686 and ARM:
if -stdlib=c++ is passed to clang, then the build errors
out with <string>,<iostrea>,etc. headers not found. Simply
not passing the arg fixes the problem.
**NOTE**: not tested on OSX.
Riccardo Spagni