ARM Compiler toolchain Using the Linker - ARM Information Center
ARM Compiler toolchain Using the Linker - ARM Information Center
ARM Compiler toolchain Using the Linker - ARM Information Center
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7.1 About mapping symbols<br />
7.1.1 See also<br />
Accessing and managing symbols with armlink<br />
Mapping symbols are generated by armcc and armasm to identify inline transitions between:<br />
• code and data at literal pool boundaries<br />
• <strong>ARM</strong> code and Thumb code, such as <strong>ARM</strong>/Thumb interworking veneers.<br />
The mapping symbols are:<br />
$a start of a sequence of <strong>ARM</strong> instructions<br />
$t start of a sequence of Thumb instructions<br />
$t.x start of a sequence of ThumbEE instructions<br />
$d start of a sequence of data items, such as a literal pool.<br />
armlink generates <strong>the</strong> $d.realdata mapping symbol to communicate to fromelf that <strong>the</strong> data is<br />
from a non-executable section. Therefore, <strong>the</strong> code and data sizes output by fromelf -z are <strong>the</strong><br />
same as <strong>the</strong> output from armlink --info sizes, for example:<br />
Code (inc. data) RO Data<br />
x y z<br />
In this example, <strong>the</strong> y is marked with $d, and RO Data is marked with $d.realdata.<br />
Note<br />
Symbols beginning with <strong>the</strong> characters $v are mapping symbols related to VFP and might be<br />
output when building for a target with VFP. Avoid using symbols beginning with $v in your<br />
source code.<br />
Be aware that <strong>the</strong> modifying an executable image with <strong>the</strong> fromelf --elf --strip=localsymbols<br />
command removes all mapping symbols from <strong>the</strong> image.<br />
Concepts<br />
<strong>Using</strong> <strong>the</strong> Assembler:<br />
• Symbol naming rules on page 8-3.<br />
Reference<br />
<strong>Linker</strong> Reference:<br />
• --list_mapping_symbols, --no_list_mapping_symbols on page 2-103<br />
• --strict_symbols, --no_strict_symbols on page 2-161.<br />
<strong>Using</strong> <strong>the</strong> fromelf Image Converter:<br />
• --strip=option[,option,...] on page 4-70<br />
• --text on page 4-73.<br />
O<strong>the</strong>r information<br />
• ELF for <strong>the</strong> <strong>ARM</strong> Architecture,<br />
http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044-/index.html.<br />
<strong>ARM</strong> DUI 0474C Copyright © 2010-2011 <strong>ARM</strong>. All rights reserved. 7-3<br />
ID080411 Non-Confidential