About mapping symbols
Mapping symbols are generated by the compiler and assembler to identify inline transitions between code and data at literal pool boundaries, and between ARM code and Thumb code, such as ARM/Thumb interworking veneers.
The mapping symbols are:
- Start of a sequence of ARM instructions.
- Start of a sequence of Thumb instructions.
- Start of a sequence of ThumbEE instructions.
- Start of a sequence of data items, such as a literal pool.
armlink generates the
$d.realdata mapping symbol to
communicate to fromelf that the data is from a non-executable section.
Therefore, the code and data sizes output by
are the same as the output from
armlink --info sizes,
Code (inc. data) RO Data x y z
In this example, the
y is marked with
Data is marked with
$vare mapping symbols related to VFP and might be output when building for a target with VFP. Avoid using symbols beginning with
$vin your source code.
Be aware that modifying an executable image with the
--elf --strip=localsymbols command removes all mapping symbols from the