[clang] [analyzer] Refactor recognition of the errno getter functions (PR #91531)

[Balazs Benics via cfe-commits]

=?utf-8?q?Donát?= Nagy <donat.nagy at ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.nagy at ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.nagy at ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.nagy at ericsson.com>
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In-Reply-To: <llvm.org/llvm/llvm-project/pull/91531 at github.com>


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@@ -136,53 +100,49 @@ void ErrnoModeling::checkBeginFunction(CheckerContext &C) const {
   ASTContext &ACtx = C.getASTContext();
   ProgramStateRef State = C.getState();
 
-  if (const auto *ErrnoVar = dyn_cast_or_null<VarDecl>(ErrnoDecl)) {
-    // There is an external 'errno' variable.
-    // Use its memory region.
-    // The memory region for an 'errno'-like variable is allocated in system
-    // space by MemRegionManager.
-    const MemRegion *ErrnoR =
-        State->getRegion(ErrnoVar, C.getLocationContext());
+  const MemRegion *ErrnoR;
----------------
steakhal wrote:

```suggestion
  const MemRegion *ErrnoR = nullptr;
```

https://github.com/llvm/llvm-project/pull/91531