problem porting Zephyr to new architecture (Renesas RX65N): architecture-specific GCC is adding leading underscores

Jan Peters

Hello all,

I'm part of a team that is porting Zephyr to Renesas RX65N processors, and we have encountered a bit of a problem. The GCC toolchain for the processor (available at by default adds leading underscores to C-Symbols. These lead to problems with Zephyr Linker scripts and at least one build-script (, which do expect symbols from C-code without these underscores. We have contacted the developers of the Renesas GCC and they told us that this a a common behaviour ("for 20 out of the 50 targets of the GCC"). Has this problem been encountered before with other toolchains used to build Zephyr ? Does anyone have an idea how it can be solved (using the GCC option -fno-leading-underscore leads to problems with gcclib, which does assume the leading undescores) ?