[PATCH] D49438: [analyzer][UninitializedObjectChecker] New flag to turn off dereferencing

[Umann Kristóf via Phabricator via cfe-commits]

Szelethus created this revision.
Szelethus added reviewers: NoQ, george.karpenkov, rnkovacs, xazax.hun.
Herald added subscribers: cfe-commits, mikhail.ramalho, a.sidorin, szepet, whisperity.

The idea came from both @george.karpenkov (https://reviews.llvm.org/D45532#1145592) and from bugzilla (https://bugs.llvm.org/show_bug.cgi?id=37965).

Assigning an object with uninitialized value to a pointer/reference could be intentional, especially if one writes a class that just initializes values.

  struct Initializer {
    int *a;
  
    void initialize(/* ... */) {
      a = /* ... */;
    }
    
    Initializer(int *a) : a(a) {}
  };
  
  void f() {
    int b;
    Initializer init(&b);
    // ...
    init.initialize(/* ... */);
  }

I actually have seen some examples for this in LLVM. While I absolutely agree that a flag like this would be neat, I also think that it should be disabled by default, as for example some objects are only created with `malloc`/`new`, and because I didn't find this functionality to be too noisy.


Repository:
  rC Clang

https://reviews.llvm.org/D49438

Files:
  lib/StaticAnalyzer/Checkers/UninitializedObjectChecker.cpp
  test/Analysis/cxx-uninitialized-no-dereference.cpp

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