ARM Compiler toolchain Using the Linker - ARM Information Center

5.6 Example of using linker feedback
To see how linker feedback works:
1. Create a file fb.c containing the code shown in this example:
#include
void legacy()
{
printf("This is a legacy function that is no longer used.\n");
}
int cubed(int i)
{
return i*i*i;
}
void main()
{
int n = 3;
printf("%d cubed = %d\n",n,cubed(n));
}
Using linker optimizations
Example 5-1 Feedback example
2. Compile the program, and ignore the warning that the feedback file does not exist:
armcc --asm -c --feedback fb.txt fb.c
This inlines the cubed() function by default, and creates an assembler file fb.s and an
object file fb.o. In the assembler file, the code for legacy() and cubed() is still present.
Because of the inlining, there is no call to cubed() from main.
An out-of-line copy of cubed() is kept because it is not declared as static.
3. Link the object file to create the linker feedback file with the command line:
armlink --info sizes --list fbout1.txt --feedback fb.txt fb.o -o fb.axf
Linker diagnostics are output to the file fbout1.txt.
The linker feedback file identifies the source file that contains the unused functions in a
comment (not used by the compiler) and includes entries for the legacy() and cubed()
functions:
;## ARM Linker, RVCT ver [Build num]: Last Updated: Date
;VERSION 0.2
;FILE fb.o
cubed