ARM ELF

ARM standard section names and their meanings (continued)

4.3 Section headers

Figure 4-5, ARM-EABI-specific values for sh_flags

4.3.1 Common sections

The SHF_COMDEF attribute denotes that there may be multiple definitions of this section. From each set of identically named sections having the SHF_COMDEF attribute, the linker retains only one representative (but it retains all identically named sections not having the SHF_COMDEF attribute).

Object producers must ensure that it does not matter which variant of a common section is retained. In general, this requires:

All variants of a common section must define the same global symbols.

If the section contains code, all variants must have the same functional interface. However, different variants may have a different size, a different content, or be differently relocated.

If the section contains data, all variants must have the same size, the same content, and be similarly relocated.

This specification does not define which variant of a common section a linker should retain.

4.3.2 Section alignment

The ARM EABI requires that each executable section must be aligned on a 4-byte boundary. Any section having the SHF_ALLOC attribute must have sh_addralign ≥ 4. Other sections can be aligned as required. For example, debugging tables usually have no alignment requirements, and data sections input to a static linker can be naturally aligned.