The Base Platform linking model enables you to:

• Create images with a memory map described in a scatter file.
• Have dynamic relocations so the images can be dynamically linked. The dynamic relocations can also target within the same image.

To link with the Base Platform model, use the --base_platform command-line option.

If you specify this option, the linker acts as if you specified --bpabi, with the following exceptions:

• Scatter-loading is available with --scatter, in addition to the following options:

  • --dll.
  • --force_so_throw, --no_force_so_throw.
  • --pltgot=type is restricted to types none or direct.
  • --ro_base=address.
  • --rosplit.
  • --rw_base=address.
  • [BETA] --rwpi.

• The default value of the --pltgot option is different to that for --bpabi:

  • For --base_platform, the default is --pltgot=none.
  • For --bpabi the default is --pltgot=direct.

• If you do not use a scatter file, the linker can ensure that the Procedure Linkage Table (PLT) section is placed correctly, and contains entries for calls only to imported symbols. If you specify a scatter file, the linker might not be able to find a suitable location to place the PLT.

  Each load region containing code might require a PLT section to indirect calls from the load region to functions where the address is not known at static link time. The PLT section for a load region LR must be placed in LR and be accessible at all times to code within LR.

  To ensure calls between relocated load regions use a PLT entry:

  • Use the --pltgot=direct option to turn on PLT generation.
  • Use the --pltgot_opts=crosslr option to add entries in the PLT for calls between RELOC load regions. The linker generates a PLT for each load region so that calls do not have to be extended to reach a distant PLT.

Be aware of the following:

• The model by default assumes that shared objects cannot throw a C++ exception (--no_force_so_throw).
• You must use symbol versioning to ensure that all the required symbols are available at load time.
• There are restrictions on the type of scatter files you can use.