[PATCH] D148381: [WIP][Clang] Add counted_by attribute

[Yeoul Na via Phabricator via cfe-commits]

rapidsna added a comment.

> Future additions will include supporting, FAMs and counts in

sub-structures.

For sub-structures, are you referring to cases like this?

  struct outer {
    struct {
      int count;
    } sub;
    int flex[__attribute__((counted_by(sub.count)))];
  };

For `-fbounds-safety` we would limit it to anonymous sub-structs only because otherwise the code can create a pointer to sub-struct and its count can easily be updated to an invalid count. Were you considering the same restrictions for this?

  void foo(struct outer *p1, struct sub *p2) {
    p1 = (int*)malloc(sizeof(int) *10);
    p1->count = 10;
  
    p2->count = INT_MAX;
  }


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D148381/new/

https://reviews.llvm.org/D148381