Support for RISC-V builds

[braydonf]

Attempted to build on strfry with RVA23 Spacemit K3 and SiFive U74 RISC-V cores and received the following error:

In file included from golpe/external/json/include/tao/json/events/../internal/number_state.hpp:13,
                 from golpe/external/json/include/tao/json/events/../internal/action.hpp:16,
                 from golpe/external/json/include/tao/json/events/from_file.hpp:7,
                 from golpe/external/json/include/tao/json/from_file.hpp:9,
                 from golpe/external/json/include/tao/json.hpp:11:
golpe/external/json/include/tao/json/events/../internal/../external/double.hpp:77:2: error: #error Target architecture was not detected as supported by Double-Conversion.
   77 | #error Target architecture was not detected as supported by Double-Conversion.
      |  ^~~~~
make: *** [golpe/rules.mk:32: golpe/logging.o] Error 1
make: *** Waiting for unfinished jobs....
make: *** [golpe/rules.mk:32: build/main.o] Error 1
make: *** [golpe/rules.mk:32: src/Decompressor.o] Error 1
make: *** [golpe/rules.mk:32: build/config.o] Error 1

There may be other errors; however, this was the first and possibly only one. Might be a simple fix?

[theAnuragMishra]

Can you try adding defined(__riscv) to the target architecture checks in golpe/external/json/include/tao/json/external/double.hpp.

[braydonf]

Compilation finished with defined(__riscv) added. Updating this library should be the only requirement to build for riscv systems.

There was only a warning for a header:

g++ -std=c++20 -O3 -g -Wall -fPIC  -DDOCOPT_HEADER_ONLY -Iinclude -Ibuild -Isrc -Igolpe/external -Igolpe/external/lmdbxx/include -Igolpe/external/config/include -Igolpe/external/json/include -Igolpe/external/PEGTL/include -Igolpe/external/hoytech-cpp -Igolpe/external/docopt.cpp -Igolpe/external/loguru -Igolpe/external/parallel-hashmap -Igolpe/external/session-token-cpp/include -Iexternal/negentropy/cpp -MMD -MP -MT src/apps/mesh/cmd_stream.o -MF src/apps/mesh/cmd_stream.d -c src/apps/mesh/cmd_stream.cpp -o src/apps/mesh/cmd_stream.o
In file included from golpe/external/PEGTL/include/tao/pegtl/demangle.hpp:8,
                 from golpe/external/PEGTL/include/tao/pegtl.hpp:9,
                 from golpe/external/json/include/tao/json/pointer.hpp:15,
                 from golpe/external/json/include/tao/json/basic_value.hpp:34,
                 from golpe/external/json/include/tao/json/value.hpp:7,
                 from golpe/external/json/include/tao/json.hpp:8,
                 from src/apps/mesh/cmd_stream.cpp:2:
/usr/include/c++/15/ciso646:49:6: warning: #warning "<ciso646> is not a standard header since C++20, use <version> to detect implementation-specific macros" [-Wcpp]
   49 | #    warning "<ciso646> is not a standard header since C++20, use <version> to detect implementation-specific macros"
      |      ^~~~~~~

[hoytech]

Thanks for solving this guys. I added an issue in the upstream json library:

taocpp/json#163

[braydonf]

Great thanks!

Also tried running the test suite (./test/runTests.sh) and ran into an error given by ./strfry relay:

date       time         ( uptime  ) [ thread name/id ]   v| 
2026-09-01 12:14:51.744 (   0.058s) [main thread     ]INFO| arguments: ./strfry relay
2026-09-01 12:14:51.744 (   0.058s) [main thread     ]INFO| Current dir: /home/ubuntu/software/strfry
2026-09-01 12:14:51.744 (   0.058s) [main thread     ]INFO| stderr verbosity: 0
2026-09-01 12:14:51.744 (   0.058s) [main thread     ]INFO| -----------------------------------
2026-09-01 12:14:51.744 (   0.058s) [main thread     ]INFO| CONFIG: Loading config from file: ./strfry.conf
2026-09-01 12:14:51.792 (   0.106s) [main thread     ]INFO| CONFIG: successfully installed
strfry error: mdb_env_open: Cannot allocate memory
2026-09-01 12:14:51.792 (   0.106s) [main thread     ]INFO| atexit

System: Ubuntu 26.04
Processor/Hardware: Spacemit K3 (RVA23) / Milk-V Jupiter2 / K3 Pico-ITX
Kernel: 6.18.3-6-spacemit-generic (Linux ubuntu 6.18.3-6-spacemit-generic #0 SMP PREEMPT_DYNAMIC Thu May 28 05:29:25 UTC 2026 riscv64 GNU/Linux)

Also compiled LMDB and all tests passed from:
https://github.com/LMDB/lmdb/tree/mdb.master3/libraries/liblmdb

[hoytech]

Hmm for some reason LMDB can't seem to allocate a large enough virtual memory size. Can you try with a smaller mapsize, like this?

./strfry --set dbParams.mapsize=1000000 relay

[braydonf]

Yes, that works!

[braydonf]

All tests passed after setting dbParams.mapsize to 180000000000.

These files needed to have the dbParams.mapsize set:

• test/utils/relay.js
• test/cfgs/test.conf
• test/cfgs/syncTest2.conf
• test/cfgs/syncTest1.conf
• strfry.conf

This was compiled with || (defined(__riscv) && __riscv_xlen == 64) added to include/tao/json/external/double.hpp after defined(__aarch64__) on line 65.

The root filesystem was around 118G in size. I also upgraded to kernel version 6.18.3-7-spacemit-generic (unrelated).