In the elf binaries generated by msp430-elf-gcc, rodata should have the READONLY attribute set, otherwise msp430-elf-size counts .rodata as part of .data, causing incorrect SRAM usage estimates. I worked around this by moving the C++ sections (.ctor, .dtor, etc) in .rodata to their own section (see stackoverflow), but I'm not sure this is correct. In any case it should be patched upstream.
-> % msp430-elf-objdump -h bl.elf
bl.elf: file format elf32-msp430
Sections:
Idx Name Size VMA LMA File off Algn
0 .rodata 000000c0 0000f000 0000f000 000000d4 2**2
CONTENTS, ALLOC, LOAD, DATA
1 __reset_vector 00000002 0000fffe 0000fffe 00000cca 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA