[PATCH] D63668: [Support] Improve zero-size allocation with safe_malloc, etc.

[Hubert Tong via Phabricator via llvm-commits]

hubert.reinterpretcast added a comment.

> I don't believe this is the right way to go, however. As you point out malloc(0) is undefined behavior

It isn't. It is implementation-defined whether or not it returns a null pointer. In either case, it returns a value on which `free` can be safely called.

> I would think that asking for 0 bytes would be indicative of a bug that can be found in testing debug builds. Personally, `assert(Sz && "Tried to allocate 0")` seems like it would suffice, but I see why you went in this direction.

`malloc` and friends are supposed to succeed when asked for 0 bytes except when there is insufficient space. The caller is within its rights to ask for 0 bytes and expect a value on which it may call `free` except when there is insufficient space.


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https://reviews.llvm.org/D63668