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Memory/Address Sanitizer vs Valgrind


I want some tool to diagnose use-after-free bugs and uninitialized bugs. I am considering Sanitizer(Memory and/or Address) and Valgrind. But I have very little idea about their advantages and disadvantages. Can anyone tell the main features, differences and pros/cons of Sanitizer and Valgrind?

Edit: I found some of comparisons like: Valgrind uses DBI(dynamic binary instrumentation) and Sanitizer uses CTI(compile-time instrumentation). Valgrind makes the program much slower(20x) whether Sanitizer runs much faster than Valgrind(2x). If anyone can give me some more important points to consider, it will be a great help.


Solution

  • I think you'll find this wiki useful.

    TLDR main advantages of sanitizers are

    • much smaller CPU overheads (Lsan is practically free, UBsan/Isan is 1.25x, Asan and Msan are 2-4x for computationally intensive tasks and 1.05-1.1x for GUIs, Tsan is 5-15x)
    • wider class of detected errors (stack and global overflows, use-after-return/scope)
    • full support of multi-threaded apps (Valgrind support for multi-threading is a joke)
    • much smaller memory overhead (up to 2x for Asan, up to 3x for Msan, up to 10x for Tsan which is way better than Valgrind)

    Disadvantages are

    • more complicated integration (you need to teach your build system to understand Asan and sometimes work around limitations/bugs in Asan itself, you also need to use relatively recent compiler)
    • MemorySanitizer is not easily usable at the moment as it requires rebuilding all dependencies under Msan (including all standard libraries e.g. libc++); this means that casual users can only use Valgrind for detecting uninitialized errors
    • sanitizers typically can not be combined with each other (the only supported combination is Asan+UBsan+Lsan) which means that you'll have to do separate QA runs to catch all types of bugs