Reproducibility

1. OCCAM needs to generate bitcode from the source code. This might not be easy and different platforms might require different workarounds.

2. OCCAM links the debloated bitcode with other debloated libraries and extra native libraries indicated in the native_libs field from the Manifest. Missing a native library or adding a native library that is not installed will make the whole process to fail.

The directory portfolio and trimmer are mostly tested on an Ubuntu 18.04 machine. But you need to make sure that all libraries passed in the Manifest as native_libs are installed in your machine.

Benchmark runner for OCCAM

To run OCCAM on a set of benchmarks and show metrics, type:

runbench.py --sets="portfolio.set"

If you want to run more than one benchmark set then add more .set files in the option --sets separated by comma:

runbench.py --sets="portfolio.set,spec2006.set"

If you want to pass extra options to slash then type:

runbench.py --sets="portfolio.set" --slash-opts="--disable-inlining"

If you want to pass multiple options by separating them by comma:

runbench.py --sets="portfolio.set" --slash-opts="--disable-inlining,--enable-config-prime"

If you want to add a timeout or memory limit then type:

runbench.py --sets="portfolio.set" --cpu=60 --mem=4096

By default, runbench.py runs OCCAM on the set of benchmarks selected by option --sets and displays the number of functions, number of instructions, etc. before and after the specialization takes place. The option --sets is mandatory and expects a list of .set files separated by comma.

The options --cpu and --mem set limits on CPU (in seconds) and memory (in MB) for running OCCAM. The compilation of the programs is unconstrained.

runbench.py reads from the *.set files to select which benchmarks to run. Each *.set file is in JSON format. For each benchmark, there are at three fields: dirname, a relative path wrt environment OCCAM_HOME variable, execname, the name of the executable, and enabled whether the benchmark is enabled or not. That directory must contain Makefile and build.sh. The makefile generates the bitcode for the benchmark, and build.sh runs OCCAM on it. The assumption is that after running build.sh two executables are generated: one with suffix _orig and the other with suffix _slashed. The executables are used by option --rop so it is important to follow this convention.

For instance, the output of runbench.py might look like this:

Program Reduction: (B:before and A:after OCCAM)

Program    B Fun   A Fun   % Fun Red   B Ins    A Ins   % Ins Red   B Mem Ins   A Mem Ins   % Mem Ins Red
tree         106      93          12    7409     8921         -20        1615        1186              26
readelf      384     281          26   83390   111227         -33        6117        7714             -26
bzip2         92      41          55   22047    19055          13        4761        4303               9
mcf           43      22          48    2592     2388           7         654         488              25

Benchmark categories

• portfolio: some real applications
• spec2006: SPEC 2006 benchmarks
• coreutils: coreutils benchmarks
• trimmer: Trimmer evaluation applications

Deprecated options which are not maintained anymore

The option --rop shows also the number of ROP, JOP, and SYS gadgets, before and after specialization.

Gadget Reduction: (B:before and A:after OCCAM)

Program    B ROP   A ROP   % ROP Red   B SYS   A SYS   % SYS Red   B JOP   A JOP   % JOP Red
tree         313     256          18       0       0           0      64      39          39
readelf     4007    3868           3       1       3        -200    2276     873          61
bzip2        479     971        -102       0       0           0      60     140        -133
mcf          168     115          31       0       0           0       0       0           0

Red means reduction. If the percentage is negative then it means that there was an increase.

This material is based upon work supported by the National Science Foundation under Grant ACI-1440800. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.