[PATCH] D64883: Add new warning -Walloca for use of builtin alloca function

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman marked an inline comment as done.
aaron.ballman added inline comments.


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Comment at: clang/lib/Sema/SemaChecking.cpp:1172
       return ExprError();
+    LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
----------------
ziyig wrote:
> aaron.ballman wrote:
> > Do we want to warn on all uses of alloca(), or just the ones that get past the call to `SemaBuiltinAllocaWithAlign()`?
> I don't have strong opinion about this. Which one do you think is better?
I think the code is fine as-is. `SemaBuiltinAllocaWithAlign()` returns true when there's an error with the call, and so users will not get the warning only if the call is erroneous, which seems fine given that the code didn't compile. It turns out this matches GCC's behavior as well.


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Comment at: clang/lib/Sema/SemaChecking.cpp:1175
+    Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+        << TheCall->getDirectCallee()->getNameInfo().getAsString();
     break;
----------------
You should pass in `TheCall->getDirectCallee()` and not try to get the name directly; the diagnostics engine will do the right thing automatically.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64883/new/

https://reviews.llvm.org/D64883