Liviu Ionescu’s gnu-mcu-eclipse has semihosting support.
https://gnu-mcu-eclipse.github.io/
SiFive is working on semihosting support now, and plan to make it available in a future toolchain release.
Meanwhile, Liviu’s semihosting patches are in openocd that you already found. Keith Packard of SiFive has qemu semihosting patches that have been posted upstream but not accepted yet, they asked for a formal spec first. So there should be someone working on a formal proposal for RISC-V semihosting support based on Liviu’s work maybe as part of the debug spec, but I’m not part of that discussion.
I haven’t used the semihosting support, but as far as I know it works the same as the arm semihosting support.