chinrw / toy-kint

cs526-project

HelloWorld: Your First Pass

The HelloWorld pass from HelloWorld.cpp is a self-contained reference example. The corresponding CMakeLists.txt implements the minimum set-up for an out-of-source pass.

For every function defined in the input module, HelloWorld prints its name and the number of arguments that it takes. You can build it like this:

export LLVM_DIR=<installation/dir/of/llvm/16>
cmake -DLT_LLVM_INSTALL_DIR=$LLVM_DIR -GNinja -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=1 && cmake --build ./build/ -v

Before you can test it, you need to prepare an input file:

# Make sure inside build folder generate an LLVM test file
$LLVM_DIR/bin/clang -Xclang -disable-O0-optnone -S -emit-llvm ./tests/input_for_hello.c -o ./build/input_for_hello.ll

Finally, run HelloWorld with opt (use libHelloWorld.so on Linux and libHelloWorld.dylib on Mac OS):

# Run the pass
$LLVM_DIR/bin/opt -load-pass-plugin ./build/lib/libHelloWorld.so -passes=hello-world -disable-output ./build/input_for_hello.ll
# Expected output
(llvm-tutor) Hello from: foo
(llvm-tutor)   number of arguments: 1
(llvm-tutor) Hello from: bar
(llvm-tutor)   number of arguments: 2
(llvm-tutor) Hello from: fez
(llvm-tutor)   number of arguments: 3
(llvm-tutor) Hello from: main
(llvm-tutor)   number of arguments: 2

The HelloWorld pass doesn't modify the input module. The -disable-output flag is used to prevent opt from printing the output bitcode file.

Kint

For Kint the command is slightly different

export LLVM_DIR=<installation/dir/of/llvm/16>
cmake -DLT_LLVM_INSTALL_DIR=$LLVM_DIR -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=1 && cmake --build ./build/

Before you can test it, you need to prepare an input file:

# Make sure inside build folder generate an LLVM test file
$LLVM_DIR/bin/clang -O0 -Xclang -disable-O0-optnone -S -emit-llvm ./tests/input_for_cc.c -o ./build/input_for_cc.ll
$LLVM_DIR/bin/opt -passes="mem2reg,dce" -S ./build/input_for_cc.ll -o ./build/input_for_cc.ll
$LLVM_DIR/bin/clang -O0 -Xclang -disable-O0-optnone -S -emit-llvm ./tests/input_for_taint.c -o ./build/input_for_taint.ll

Finally, run KINT with opt (use KINT.so) on Linux

# Run the pass
$LLVM_DIR/bin/opt -load-pass-plugin ./build/lib/KINT.so -passes=check-insertion-pass,smt-query-pass -disable-output ./build/input_for_cc.ll
$LLVM_DIR/bin/opt -load-pass-plugin ./build/lib/KINT.so -passes=kint-range-analysis -disable-output ./build/input_for_taint.ll