[clang] [-Wunsafe-buffer-usage] Separate flag for format-attributed functions (PR #175749)

[Ziqing Luo via cfe-commits]

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@@ -2523,7 +2523,12 @@ class UnsafeBufferUsageReporter : public UnsafeBufferUsageHandler {
   void handleUnsafeLibcCall(const CallExpr *Call, unsigned PrintfInfo,
                             ASTContext &Ctx,
                             const Expr *UnsafeArg = nullptr) override {
-    S.Diag(Call->getBeginLoc(), diag::warn_unsafe_buffer_libc_call)
+    unsigned DiagID = diag::warn_unsafe_buffer_libc_call;
+    if (PrintfInfo & 0x8) {
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ziqingluo-90 wrote:

Please add some comments to explain 0x8 here.  Maybe it's time to refactor `PrintfInfo ` to an `enum` here (in another patch of course).

https://github.com/llvm/llvm-project/pull/175749