[PATCH] D14497: [FunctionAttrs] Detect printf-like functions and propagate readnone+nocapture to variadic operands

[Eli Friedman via llvm-commits]

eli.friedman added a subscriber: eli.friedman.
eli.friedman added a comment.

sprintf definitely isn't nocapture; simple testcase:

  #include <stdio.h>
  #include <assert.h>
  int main() {
      int a = 3;
      // Serialize the address of `a`
      char buf[32];
      sprintf(buf, "%p", &a);
      // Deserialize the address of `a`
      int* aptr;
      sscanf(buf, "%p", &aptr);
      // Check value of `a`
      assert(*aptr == 3);
  }

sprintf can also write to its arguments: "%n" might not be particularly popular, but it's still legal.


Repository:
  rL LLVM

http://reviews.llvm.org/D14497