The IAR toolchain cannot guarantee the order of variables in memory based on the input order from a C file.
It is necessary to force the order via a structure or by manipulating the linker file with additional sections.
There is no flag or additional setting to change this behavior.
So :-
1) Put all the variable is a structure, to guarantee the order of variables in memory.
2) Assign each variable it's own section as described here www.iar.com/.../contiguous-variables