mpictor / cSTACK

A static checker for identifying unstable code.

STACK code analyzer

find optimization-unstable code

This is a fork of STACK which uses CMake as the build system and builds the dependencies (including llvm and clang) automatically and with the correct options - no more having to go through the many steps necessary to get special builds of llvm and clang working without interfering with the system versions.

Once this works well, I will approach STACK's authors about merging my changes.

INSTALL will contain build instructions - this isn't in a working state yet.

Make sure STACK binaries are in the PATH.

Preparation

STACK works on LLVM bitcode. To analyze a software project, the first step is to generate LLVM bitcode. STACK provides a script called stack-build, which both calls gcc (or g++) and in parallel uses Clang to obtain LLVM bitcode from your source code, stored in .ll files. For example:

$ cd /path/to/your/project
$ stack-build ./configure
$ stack-build make

or if analyzing a project that is configured using CMake:

$ cd /path/to/your/project
$ stack-build cmake
$ stack-build make

Unstable code checker

To find unstable code that can be eliminated due to undefined behavior, simply run the following command in the project directory after building LLVM bitcode:

$ poptck

You can find bug reports in pstack.txt, in the YAML format.

Here's one example:

bug: anti-simplify
model: |
  %tobool = icmp ne i8* %p, null, !dbg !14
  -->  true
stack: 
  - p.c:4:0
ncore: 1
core: 
  - p.c:3:0
    - null pointer dereference

This means the null pointer check at line 4 ("stack:") may be simplified into true ("model:") due to the pointer dereference at line 3 ("core:").

Contact

If you find any bugs in STACK, feel free to contact us: you can send us email at [e-mail].