Cannot compile on ARMv7

[takgr]

Hi Oona and thanks for this beautiful software! Trying to compile on ARMv7 (Allwiner H2+) fails with the following error:

make all-recursive make[1]: Entering directory '/root/redsea' Making all in src make[2]: Entering directory '/root/redsea/src' g++ -DHAVE_CONFIG_H -I. -I.. -std=c++14 -Wall -Wextra -Wstrict-overflow -Wshadow -Wuninitialized -pedantic -g -O2 -MT redsea-block_sync.o -MD -MP -MF .deps/redsea-block_sync.Tpo -c -o redsea-block_sync.o test -f 'block_sync.cc' || echo './'block_sync.cc In file included from ../src/groups.h:36:0, from ../src/block_sync.h:24, from block_sync.cc:17: ../src/tmc/tmc.h:152:40: warning: missing initializer for member ‘std::array<short unsigned int, 2u>::_M_elems’ [-Wmissing-field-initializers] std::array<uint16_t, 2> data {}; ^ ../src/tmc/tmc.h:195:38: warning: missing initializer for member ‘std::array<redsea::tmc::MessagePart, 5u>::_Melems’ [-Wmissing-field-initializers] std::array<MessagePart, 5> parts {}; ^ In file included from ../src/block_sync.h:24:0, from block_sync.cc:17: ../src/groups.h:155:33: warning: missing initializer for member ‘std::array<redsea::Block, 4u>::_Melems’ [-Wmissing-field-initializers] std::array<Block, 4> blocks {}; ^ block_sync.cc: In function ‘constexpr redsea::eBlockNumber redsea::BlockNumberForOffset(redsea::Offset)’: block_sync.cc:31:19: warning: compound-statement in constexpr function [-Wpedantic] switch (offset) { ^ block_sync.cc:42:1: error: body of constexpr function ‘constexpr redsea::eBlockNumber redsea::BlockNumberForOffset(redsea::Offset)’ not a return-statement } ^ block_sync.cc: In function ‘constexpr redsea::Offset redsea::NextOffsetFor(redsea::Offset)’: block_sync.cc:46:24: warning: compound-statement in constexpr function [-Wpedantic] switch (this_offset) { ^ block_sync.cc:56:1: error: body of constexpr function ‘constexpr redsea::Offset redsea::NextOffsetFor(redsea::Offset)’ not a return-statement } ^ block_sync.cc: In function ‘constexpr redsea::Offset redsea::OffsetForSyndrome(uint16_t)’: block_sync.cc:60:21: warning: compound-statement in constexpr function [-Wpedantic] switch (syndrome) { ^ block_sync.cc:69:1: error: body of constexpr function ‘constexpr redsea::Offset redsea::OffsetForSyndrome(uint16_t)’ not a return-statement } ^ block_sync.cc: In member function ‘void redsea::SyncPulseBuffer::Push(redsea::Offset, int)’: block_sync.cc:175:17: error: no match for ‘operator=’ (operand types are ‘std::array<redsea::SyncPulse, 4u>::value_type {aka redsea::SyncPulse}’ and ‘’) pulses.back() = {offset, bitcount}; ^ block_sync.cc:175:17: note: candidates are: In file included from block_sync.cc:17:0: ../src/block_sync.h:29:8: note: redsea::SyncPulse& redsea::SyncPulse::operator=(const redsea::SyncPulse&) struct SyncPulse { ^ ../src/block_sync.h:29:8: note: no known conversion for argument 1 from ‘’ to ‘const redsea::SyncPulse&’ ../src/block_sync.h:29:8: note: redsea::SyncPulse& redsea::SyncPulse::operator=(redsea::SyncPulse&&) ../src/block_sync.h:29:8: note: no known conversion for argument 1 from ‘’ to ‘redsea::SyncPulse&&’ In file included from ../src/tmc/tmc.h:36:0, from ../src/groups.h:36, from ../src/block_sync.h:24, from block_sync.cc:17: ../src/util.h: In instantiation of ‘redsea::RunningSum::RunningSum() [with unsigned int N = 50u]’: block_sync.cc:195:19: required from here ../src/util.h:107:16: warning: missing initializer for member ‘std::array<int, 50u>::_M_elems’ [-Wmissing-field-initializers] RunningSum() {}; ^ ../src/util.h: In instantiation of ‘redsea::RunningAverage::RunningAverage() [with unsigned int N = 12u]’: block_sync.cc:195:19: required from here ../src/util.h:127:20: warning: missing initializer for member ‘std::array<int, 12u>::_M_elems’ [-Wmissing-field-initializers] RunningAverage() {}; ^ Makefile:450: recipe for target 'redsea-block_sync.o' failed make[2]: [redsea-block_sync.o] Error 1 make[2]: Leaving directory '/root/redsea/src' Makefile:410: recipe for target 'all-recursive' failed make[1]: [all-recursive] Error 1 make[1]: Leaving directory '/root/redsea' Makefile:329: recipe for target 'all' failed make: *** [all] Error 2

cat /proc/cpuinfo Processor : ARMv7 Processor rev 5 (v7l) processor : 0 BogoMIPS : 2400.00

processor : 1 BogoMIPS : 2400.00

processor : 2 BogoMIPS : 2400.00

processor : 3 BogoMIPS : 2400.00

Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc07 CPU revision : 5

Hardware : sun8i Revision : 0000

cat /etc/issue Debian GNU/Linux 8 \n \l

Linux orangepizero 3.4.113-sun8i #8 SMP PREEMPT Sat Feb 9 20:17:57 CET 2019 armv7l GNU/Linux

However on a different board with ARM64 it compiles!

Disabling TMC does not help, am I doing something wrong?

[windytan]

Thanks for the report. Just to be sure, which compiler is this? (g++ --version)

[takgr]

g++ (Debian 4.9.2-10+deb8u2) 4.9.2

[windytan]

This is due to incomplete C++14 support in GCC 4.9.

But please have a try; I have now modified these parts of the code to work with 4.9. This change is now in the current master branch.

[takgr]

It works now!!!! Thank a lot for such a fast response and fix! I'm now REaDy to sail the SEA of RDS!!!