These tools aim to answer two questions:
  1. How do the individual modules of SBE contribute to code/data size?
  2. How does my code change affect the size across modules?
  3. Which symbols ended up increasing/decreasing in size?

They do so by collecting code/data size per object file and allowing
you to plot them in a stacked bar graph, or to compare two such statistics
in a similar graph.

The graphs use the object file name on the X axis, sorted alphabetically
so that each object file is at the same X location every time you generate
the graph. This should help compare similar graphs.

The tools are currently special-cased to look at a DD2 build only. This can
easily be changed by modifying collect-section-sizes.

Usage:
  0. Add the scripts to your PATH:
     export PATH=$PATH:$PWD/tools/utils/sbe-size
  1. Fully build your reference commit once
  2. mkdir ref; cp -av images obj ref
     Copy the reference build artifacts somewhere safe
  3. SBEROOT=$PWD/ref collect-section-sizes > ref/sizes.txt
     This will collect the code/data sizes for all reference object files
     into a file 'sizes.txt'. It's an ASCII file, happy viewing.
  4. Hack away at the code, rebuild.
     If you changed common header files, do a "make clean" before you build
     since the build system doesn't reliably rebuild all dependent files.
  5. collect-section-sizes > sizes.txt
     This will collect the code/data sizes for your changed build.
  6. view-section-sizes sizes.txt
     This will plot the sizes from sizes.txt using gnuplot. If your gnuplot
     supports zooming, you can zoom around the plot to examine it. When
     you're done, exit gnuplot by hitting Ctrl-D at the 'gnuplot>' prompt.
  7. compare-section-sizes ref/sizes.txt sizes.txt
     Compare two sizes files against one another. The plot will show size
     reductions as bars below the zero line, size increases as bars above.
  8. compare-section-breakdown images/sbe_seeprom_DD2.map
     Compare maps for ref/images/sbe_seeprom_DD2.map and
     images/sbe_seeprom_DD2.map, replacing addresses by a constant value
     so only the sizes are compared.
  9. compare-section-breakdown obj/power/fapi2/target.o
     Compare section sizes for ref/obj/power/fapi2/target.o and
     obj/power/fapi2/target.o - or any other object file of course.
     This will filter the C++ mangled names too.
 10. compare-section-breakdown obj/power/fapi2/target.su
     compare-section-breakdown obj/power/fapi2/target.dis
     compare-section-breakdown obj/power/fapi2/target.diss
     The same for stack usage, disassembly (with addresses normalized for
     better diffing) and assembly with source.

If you have questions, ask fenkes@de.ibm.com.