[PATCH] D141310: [clang] add -Wcompare-function-pointers

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


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Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:7007
+  "comparison of function pointers (%0 and %1)">,
+  InGroup<CompareFunctionPointers>, DefaultIgnore;
 def warn_typecheck_ordered_comparison_of_function_pointers : Warning<
----------------
cjdb wrote:
> aaron.ballman wrote:
> > cjdb wrote:
> > > cjdb wrote:
> > > > It's very rare that we set a warning to `DefaultIgnore`. What's the motivation for this?
> > > > This warning is disabled by default, since it's only relevant if ICF is explicitly enabled.
> > > 
> > > I see why now. Perhaps this warning should be enabled by default when ICF is also enabled, and an error otherwise.
> > The problem is: ICF is an lld thing, it's not a Clang thing; so Clang has no idea if ICF will or won't be enabled.
> Okay, that sounds like we can't make it an error to turn this warning on when ICF isn't enabled, but what about turning it on when the driver sees `-icf=all`? Or does that bypass `clang_cc1` altogether?
The diagnostic serves no purpose unless the user is linking with `-icf=all`, so agreed we can't enable this by default. We might be able to do something by looking at linker flags passed through clang on to the driver, but it's not going to be perfect (users can link manually without invoking through the compiler, and I'm not certain what IDEs do when driving builds with Clang).


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  https://reviews.llvm.org/D141310/new/

https://reviews.llvm.org/D141310