I'm now looking at compilation issues with our standards compliant compiler, and I run into one issue after another that are due to the use of non-standard C allowed by gcc and armclang.

Things like zero sized arrays, which are fairly easy to fix by making sure that they have at least one element, but there are other issues that may not be as easy to solve.

The latest issue is illegal pointer arithmetic on void * in the IPC code. --- ... [ 20%] Building C object app/secure_fw/CMakeFiles/tfm_s_obj_lib.dir/core/ipc/tfm_svcalls.o

msg->invec[invec_idx].base += bytes;       ^ "C:\Users\thomasto\Projects\tf-m7\trusted-firmware-m\secure_fw\core\ipc\tfm_svcalls.c",595 Error[Pe852]:           expression must be a pointer to a complete object type

msg->invec[invec_idx].base += num_bytes;       ^ "C:\Users\thomasto\Projects\tf-m7\trusted-firmware-m\secure_fw\core\ipc\tfm_svcalls.c",666 Error[Pe852]:           expression must be a pointer to a complete object type

tfm_memcpy(msg->outvec[outvec_idx].base + msg->outvec[outvec_idx].len,                  ^ "C:\Users\thomasto\Projects\tf-m7\trusted-firmware-m\secure_fw\core\ipc\tfm_svcalls.c",750 Error[Pe852]:           expression must be a pointer to a complete object type ... ---

I suggest enabling "-pedantic-errors" for gcc, and also for clang, if it has a similar setting, to avoid having illegal C code creeping into tf-m.

Comments?

/Thomas