Mapping symbols are generated by armcc and armasm to identify inline transitions between:
code and data at literal pool boundaries
ARM code and Thumb code, such as ARM/Thumb interworking veneers.
The mapping symbols are:
- $a
start of a sequence of ARM instructions
- $t
start of a sequence of Thumb instructions
- $t.x
start of a sequence of ThumbEE instructions
- $d
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 fromelf -z are the same as the output
from armlink --info sizes, for example:
Code (inc. data) RO Data
x y z
In this example, the y is marked with $d,
and RO Data is marked with $d.realdata.
Note
Symbols beginning with the characters $v are
mapping symbols related to VFP and might be output when building
for a target with VFP. Avoid using symbols beginning with $v in
your source code.
Be aware that the modifying an executable image with the fromelf --elf --strip=localsymbols command removes all mapping symbols from the image.
See also- Concepts
Using the Assembler:
- Reference
Linker Reference:
Using the fromelf Image Converter:
- Other information
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