[PATCH] D64256: Teach some warnings to respect gsl::Pointer and gsl::Owner attributes

Leonard Chan via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Mon Aug 12 16:40:27 PDT 2019

leonardchan added a comment.

In D64256#1626025 <https://reviews.llvm.org/D64256#1626025>, @xazax.hun wrote:

> In D64256#1625998 <https://reviews.llvm.org/D64256#1625998>, @leonardchan wrote:
> > Hi. I noticed in our builders that both of the warnings introduced in this patch are being diagnosed for pointers that don't use GSL at all. I'm attempting to make a small reproducer now.
> Hi!
> Clang now apply GSL annotations for some STL types automatically. So this is the expected behavior. Are any of those warnings unwanted/false positive with the newest Clang version? If so, please share the reproducers and I will either fix them ASAP or revert/turn off the warnings.

Thanks! I didn't know that they were applied to stl types. This could explain why the warning is raised in my case (std::string), but I don't think there's anything wrong in this example that would lead to a warning:

  leonardchan at cp-snakewater:~/llvm-monorepo/llvm-build-3-master$ cat ~/misc/test.cpp
  #include <string>
  std::string MakeStr();
  void other_func(const char *s);
  void func(std::string s) {
    const char *x = MakeStr().c_str();
  leonardchan at cp-snakewater:~/llvm-monorepo/llvm-build-3-master$ ~/llvm-monorepo/llvm-build-3-master/bin/clang++ -c ~/misc/test.cpp
  /usr/local/google/home/leonardchan/misc/test.cpp:7:19: warning: object backing the pointer will be destroyed at the end of the full-expression [-Wdangling]
    const char *x = MakeStr().c_str();
  1 warning generated.

This was made using a release build from ToT clang.




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