• Scons build system.
• LLVM 3.0. When building LLVM, use --enable-shared flag.

../llvm/configure --enable-shared
make

• Set the following environment variable.

CORVETTE_PATH=path/to/precimonious
LLVM_COMPILER=clang
LD_LIBRARY_PATH=path/to/llvm/Release/lib
PATH=$PATH:path/to/llvm/Release/bin

After setting up the requirement, you can build Precimonious LLVM Passes by

cd src
scons -Uc
scons -U
scons -U test // to run the regression test

• Go inside examples folder, take a look at the file funarc.c. This is the target program that we will tune precision on.

• Compile the program:

./compile.sh

This will create a bitcode file called funarc.bc.

• Generate search configuration files:

./config.sh

This will create search_funarc.json and config_funarc.json.

• Run Precimonious algorithm:

./search.sh

This will create a file called spec.cov, which contains the output and the error threshold in hex format. Each iteration of the algorithm will create a valid or invalid configuration file, and update files sat.cov, score.cov, log.cov and log.dd. Finally, this will create two files: dd2_diff_funarc.bc.json and dd2_valid_funarc.bc.json, if a faster and lower-precision type configuration of the program is found.