[PATCH] D59254: [RFC] Implementation of Clang randstruct

[JF Bastien via Phabricator via cfe-commits]

jfb added a comment.

In D59254#1566895 <https://reviews.llvm.org/D59254#1566895>, @shawnl wrote:

> My point is that most languages these days that intend to be compiled to machine code want compatibility with the C ABI, and randstruct will be part of that (and can be made compatible between languages by sharing the seed). LLVM knows what a struct is.


Basic stuff, sure LLVM can know about and move fields around, especially if clang slaps an attribute on the struct saying it's fine.

However, struct layout is deeply ingrained in code generation. Too deeply to just move it to LLVM. Consider this simple example:

  template <int Size>
  struct Arr {
      int arr[Size];
  };
  
  struct A { int a, b, c; char d, e, f, g; };
  
  Arr<__builtin_offsetof(A, d)> arr;

There's way more complex stuff that falls out of how C and C++ specify the language. That complexity really shouldn't be in scope for this patch.


Repository:
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  https://reviews.llvm.org/D59254/new/

https://reviews.llvm.org/D59254