[clang] [clang] Implement __attribute__((format_matches)) (PR #116708)

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=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/116708 at github.com>


apple-fcloutier wrote:

Happy new year, @erichkeane! Here's a summary of actions taken in response to RFC feedback and review feedback:

* We no longer accept different integer sizes (`%hhi` and `%i` are now incompatible, for instance), as [agreed](https://discourse.llvm.org/t/rfc-format-attribute-attribute-format-like/83076/12).
* Removed support for `scanf`, as Aaron brought up a few things I wasn't clear about, and I don't need it, and it wasn't really part of the RFC, and it's probably better to leave it alone until somebody who knows scanf well wants to take it over.
* Documentation was updated to clarify these 2 points.

Notably, I didn't change the handling of signedness mismatches (diagnostics are controlled by `-Wformat-signedness`): I understood this was OK when you said the RFC was good as it sat, without an agreement on changing this.

I recommend [reviewing with `?w=1`](https://github.com/llvm/llvm-project/pull/116708/files?w=1), as it brings down the size of the SemaChecking.cpp diff a good amount (down to 550ish lines).

https://github.com/llvm/llvm-project/pull/116708