yuntongzhang / rewritecond

RewriteCond

Transform conditionals in C/C++ program to assignment + reference to a single variable.

Source-to-source transformation based on clang Transformer.

Tested on Ubuntu-18 and clang-14. Other OS versions probably also work provided that the clang binaries (with version 14.0.0 and above) work on that OS.

Usage

1. Download and unzip clang and llvm binaries (version 14 or above). For ubuntu-18, download from: https://github.com/llvm/llvm-project/releases/download/llvmorg-14.0.0/clang+llvm-14.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz.

2. In this directory, run make BINARY_DIR_PATH=<path-to-unzipped-folder>. Tool should now be in build. A shortcut is created at root called rewritecond.

Running on simple example

To run the tool, do ./rewritecond examples/test.c --. The file examples/test.c shows what can be handled by the current tool.

Running on large codebase

For large codebase, a compilation database is required. First, install bear:

sudo apt install bear

To generate a compilation database, prepend the build command with bear and build the target project. For example, if the original build command is make, now it becomes bear make. After building, there should be a file compile_commands.json generated.

To run the tool, do:

./rewrite_cond <path_to_file> -o <out_file>`

The compilation database is automatically searched in the parent directories of the input file. Alternatively, specify the directory containing compile_commands.json with -p=<dir>.