[clang] [analyzer] Resolve initializers for fields of struct array elements i… (PR #189361)

[Balázs Benics via cfe-commits]

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@@ -2145,6 +2145,46 @@ SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
         }
   }
 
+  // In case of array of structs, the super-region is not directly a VarRegion,
+  // instead there is another layer of ElementRegion in between them, i.e.:
+  // FieldRegion(ElementRegion(VarRegion)).
+  if (const auto *ER = dyn_cast<ElementRegion>(superR)) {
+    if (const auto *VR = dyn_cast<VarRegion>(ER->getSuperRegion())) {
+      const VarDecl *VD = VR->getDecl();
+      QualType ArrayTy = VD->getType();
+      unsigned FieldIdx = FD->getFieldIndex();
+
+      if (ArrayTy.isConstQualified() || Ty.isConstQualified() ||
+          (B.isMainAnalysis() && VD->hasGlobalStorage())) {
+        if (const Expr *Init = VD->getAnyInitializer())
+          if (const auto *InitList = dyn_cast<InitListExpr>(Init))
+            if (const auto CI = ER->getIndex().getAs<nonloc::ConcreteInt>()) {
+              uint64_t ElemIdx = CI->getValue()->getZExtValue();
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steakhal wrote:

I didn't check what this does, but just looking at how the nesting gets out of control, I'm considering alternatives. I suspect that the `getBindingForField` is already quite large so this could be a great opportunity to implement this niche case outside of that.

https://github.com/llvm/llvm-project/pull/189361