Sanitizers

LLVM sanitizers instrument the code at compile-time to catch various illegal behaviours at runtime. Enabling them needs support from the build system, unlike Valgrind which works with any compiled binary. The advantage of the sanitizers is that they can catch more kinds of bugs.

These are the sanitizers that currently exists:

Name	Description
AddressSanitizer	Memory error detector. Can detect out-of-bounds access to heap, stack and globals, use-after-free, use-after-return, use-after-scope, double-free, invalid-free and memory leaks.
ThreadSanitizer	Data race detector.
MemorySanitizer	Uninitialized read detector.
UndefinedBehaviourSanitizer	Undefined behavior detector. Can detect array subscript out-of-bounds, bitwise shifts out-of-bounds, dereferencing misaligned or NULL pointers, signed integer overflow, conversion to or from floating-point which results in overflow.

Quick Run

In the repository root, there is a Makefile with some handy targets. These will create a new build folder with the sanitizer enabled, and then run unit tests.

make asan
make msan
make usan

There is also a script for compiling the code with a sanitizer in a temporary folder and running tests, this can be done by running the following, using the Address sanitizer for example:

./scripts/sanitizer.sh Address

Supported Sanitizers and Sanitizer combinations are Address, Memory, MemoryWithOrigins, Undefined, Thread, Leak, Address;Undefined.

Enabling Sanitizers

Enabling a specific sanitizer can be done by setting the USE_SANITIZER CMake variable when initializing the build folder.

cmake -DUSE_SANITIZER=Address

Supported Sanitizers and Sanitizer combinations are Address, Memory, MemoryWithOrigins, Undefined, Thread, Leak, Address;Undefined.

It is useful to turn on these sanitizers when running unit tests, because they catch more bugs that way. It is not recommended to leave the sanitizers enabled for release builds of Passgen, because they do add overhead (depending on the sanitizer).