Bug 297946 – Enable format string attributes in Objective-C++ sources

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[David Kilzer (:ddkilzer)]

Remove hack that disables format string attributes in Objective-C++ sources.

This is the code that disables format string attributes in Source/WTF/wtf/Assertions.h:

```
#if COMPILER(GCC_COMPATIBLE) && !defined(__OBJC__)
/* WTF logging functions can process %@ in the format string to log a NSObject* but the printf format attribute
   emits a warning when %@ is used in the format string.  Until <rdar://problem/5195437> is resolved we can't include
   the attribute when being used from Objective-C code in case it decides to use %@. */
#define WTF_ATTRIBUTE_PRINTF(formatStringArgument, extraArguments) __attribute__((__format__(printf, formatStringArgument, extraArguments)))
#else
#define WTF_ATTRIBUTE_PRINTF(formatStringArgument, extraArguments)
#endif
```

This is now fixable after this clang change from a few years ago:

<https://github.com/llvm/llvm-project/commit/91ed7e19418181ae385c2626cedd3b08b6ba43a6>

We can introduce a new attribute and a separate logging function that uses the attribute so the compiler is able to verify placeholders correctly:

__attribute__((__format__(__NSString__, format, vaargs)))

[Radar WebKit Bug Importer]

<rdar://problem/159245047>

[David Kilzer (:ddkilzer)]

Pull request: https://github.com/WebKit/WebKit/pull/49918

[EWS]

Committed 299238@main (1c37850168d7): <https://commits.webkit.org/299238@main>

Reviewed commits have been landed. Closing PR #49918 and removing active labels.