[PATCH] D42576: [test-suite] Add prototypes to functions in Olden and MiBench

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

In https://reviews.llvm.org/D42576#990020, @arichardson wrote:

> Calling K&R functions is not a problem. It is fine to use them as long as there is a declaration with the parameter types in the LLVM IR and not just an `declare i32 @foo(...)`. The problem is that we are calling functions that don't have a declaration and therefore the compiler assumes that it is a variadic function call. This leads to runtime crashes on our CHERI platform.
>
> They are not necessarily correct C programs since they include undefined behaviour


To the best of my knowledge, this is perfectly fine (even in C11):

  /* a.c: */
  short bar(x)
    short x;
  {
      return x;
  }
  
  /* b.c: */
  short bar();
  int main(void) {
      bar(42);
  }

If a compiler cannot handle it then it has a bug and I'm not in favor of changing the benchmarks/tests because of a bug. On the contrary: We need tests to uncover such bugs!

I agree with you that llvm representing prototype-less functions and variadic functions the same is unfortunate (and appears to only allow implementations where they are the same at a first glance?). Maybe ask clang or llvm mailing lists for comments...


Repository:
  rT test-suite

https://reviews.llvm.org/D42576