stack

hile the source is in LLVM: https://github.com/google/sanitizers/wiki/ThreadSanitizerCpp... http://clang.llvm.org/docs/ThreadSanitizer.html https://llvm.org/svn/llvm-project/llvm/trunk/lib/Transforms/... I was spooked by this FAQ on the Google Wiki page, though: Q: My code with C++ exceptions does not work with tsan. A: Tsan does not support C++ exceptions. Does this mean that it does not work at all on code that is written with exceptions, or that it might have false-positives or false-negatives when exceptions actually happen at runtime? -- For other tools, Intel has offers their "Parallel Inspector": https://software.intel.com/en-us/intel-inspector-xe. I haven't tried it, but it sounds like it would be useful for these issues: https://software.intel.com/en-us/get-started-with-inspector. Does anyone know how it compares with TSan? -- An example of an atomicity violation is this bug from MySQL: Thread 1: if (thd->proc_info) fputs(thd->proc_info, ...) Thread 2: thd->proc_info = NULL; While definitely a concurrency bug, I'm surprised that this would happen frequently enough to create numerous bug reports unless there is also an undesired compiler optimization that's removing the "guard" in Thread 1. That is, the window of opportunity seems very small if the code is being executed as written. I didn't look at the details of the linked bug reports, but I suspect the compiler is able to reason based on something earlier that thd->proc_info must be non-null at this point, and thus has omitted the check. If this is the case, it's possible that "Stack" would have caught this bug as well, or at least highlighted it as a place where the generated code was different than the programmer's intent. Stack is painful to install, and seems abandoned, but does catch flag some bugs that other tools miss: https://github.com/xiw/stack/ -- Does anyone know of other tools in this space? I'm still hoping there's a "silver bullet" I haven't found yet.

of compile flags. But once you have it up, it catches a lot of non-obvious errors and doesn't have many false positives. Unfortunately, in the sample code I gave above, "stack" doesn't detect any errors, because Clang doesn't doesn't optimize out the "if (string)" statement like GCC does. And it doesn't catch the switch from printf() to puts() because it's a change of which function is called rather than a change in control flow.