[PATCH] D154838: [analyzer] Add check for null pointer passed to %p of printf family

[Mital Ashok via Phabricator via cfe-commits]

MitalAshok added a comment.

Instead of checking for hard-coded names, you can check functions with the format(printf, x, y) <https://clang.llvm.org/docs/AttributeReference.html#format> attribute:

  if (auto *Format = FD->getAttr<FormatAttr>())
    CheckPrintfPointerConversionSpecifierNULL(C, CE, Format->getFormatIdx());

You also have to check for pointer types first. This currently warns on `printf("%d", 0)`, since `0` is a null pointer constant (This warning should only be `T*` pointer types, C2x and C++ `nullptr` and GNU `__null`).

Also this only works for null pointer *constants*. `printf("%p", (void*) 0)` is pretty rare. You ideally want this to warn on the following too:

  void f(void* p) {
      if (!p) printf("%p", p);
  }
  void g(void) {
      void* p = NULL;
      printf("%p", p);
  }

Look into how the NonNullParamChecker works


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D154838/new/

https://reviews.llvm.org/D154838