GDB will set bp at a function for RISC-V when step over this function call

[Simon Marchi]

On 2021-09-17 3:57 a.m., Ge, Lei wrote:
> Hi all,
> 
> I have a question about GDB for RISC-V. When step over a function call, GDB will set a bp at this function only for RISC-V. Do you think it is a bug? Thanks.

Hi,

Probably because RISC-V uses software single step to implement
single instruction stepping.  It implements the
gdbarch_software_single_step hook:

https://gitlab.com/gnutools/binutils-gdb/-/blob/master/gdb/riscv-tdep.c#L3923-3940

Note that this callback is only installed in riscv_fbsd_init_abi and
riscv_linux_init_abi, so is only effective when debugging a Linux or
FreeBSD target.  So I suppose that if you were debugging a bare-metal
application, GDB would use hardware single step instead, not sure if
that is by design.

Simon