|
||
| Products Download Events Support Videos | ||
Technical Support
On-Line Manuals
Linker User Guide
Preface
Overview of the Linker
Linking Models Supported by armlink
Image Structure and Generation
Linker Optimization Features
Elimination of common debug sections
Elimination of common groups or sections
Elimination of unused sections
Elimination of unused virtual functions
About linker feedback
Example of using linker feedback
Optimization with RW data compression
How the linker chooses a compressor
Options available to override the compression algo
How compression is applied
Considerations when working with RW data compressi
Function inlining with the linker
Factors that influence function inlining
About branches that optimize to a NOP
Linker reordering of tail calling sections
Restrictions on reordering of tail calling section
Linker merging of comment sections
Getting Image Details
Accessing and Managing Symbols with armlink
Scatter-loading Features
Scatter File Syntax
Linker Command-line Options
Linker Steering File Command Reference
Via File Syntax
About linker feedback
| Non-Confidential |  PDF version | ARM DUI0377H | ||
| ||||
| Home > Linker Optimization Features > About linker feedback | ||||
4.5 About linker feedback
Linker feedback is a collaboration between the compiler and linker that can increase the amount of unused code that can be removed from an ELF image.
The feedback option produces a text file containing a list of unused functions, and
functions that have been inlined by the linker. This information can be fed back to the
compiler, which can rebuild the objects, placing these functions in their own sections.
These sections can then be removed by the linker during usual unused section
elimination.
The feedback file has the following format:
;#<FEEDBACK># ARM Linker,N.nn[Buildnum]: Last Updated:day mmm dd hh:mm:ss yyyy;VERSION 0.2 ;FILEfilename.ounused_function<= USED 0inlined_function<= LINKER_INLINED …
The feedback file contains an entry for each object file. Each entry contains:
- The object filename specified as a comment:
;FILEfilename.o - A list of the functions in that file that are not used:
unused_function<= USED 0 - A list of the functions in that file that are inlined by the linker:
inlined_function<= LINKER_INLINED
To use linker feedback, specify
--feedback file on the
linker and compiler command lines.Note
The compiler issues a warning message if no feedback file exists. Therefore, you might
want to leave the
--feedback file option off the first
invocation of the compiler.Additional feedback options are provided by the linker:
- If you are using scatter-loading then an executable ELF image cannot be created if your code does not fit into the region limits described in your scatter file. In this case use the
--feedback_image=command-line option.option - To control the information that the linker puts into the feedback file, use the
--feedback_type=command-line option. You can control whether or not to list functions that require interworking or unused functions.type
Related concepts
Related tasks
Related reference
Related information
| Non-Confidential | PDF version | ARM DUI0377H |
| Copyright © 2007, 2008, 2011, 2012, 2014-2016 ARM. All rights reserved. |
| Home > Linker Optimization Features > About linker feedback |
ProductsDevelopment Tools |
Hardware & Collateral |
Downloads |
Support |
Contact |
 |
||||