[clang] [HLSL] Global resource arrays element access (PR #152454)

[Helena Kotas via cfe-commits]

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@@ -84,6 +85,111 @@ void addRootSignature(llvm::dxbc::RootSignatureVersion RootSigVer,
   RootSignatureValMD->addOperand(MDVals);
 }
 
+// Find array variable declaration from nested array subscript AST nodes
+static const ValueDecl *getArrayDecl(const ArraySubscriptExpr *ASE) {
+  const Expr *E = nullptr;
+  while (ASE != nullptr) {
+    E = ASE->getBase()->IgnoreImpCasts();
+    if (!E)
+      return nullptr;
+    ASE = dyn_cast<ArraySubscriptExpr>(E);
+  }
+  if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(E))
+    return DRE->getDecl();
+  return nullptr;
+}
+
+// Get the total size of the array, or -1 if the array is unbounded.
+static int getTotalArraySize(ASTContext &AST, const clang::Type *Ty) {
+  Ty = Ty->getUnqualifiedDesugaredType();
+  assert(Ty->isArrayType() && "expected array type");
+  if (Ty->isIncompleteArrayType())
+    return -1;
+  return AST.getConstantArrayElementCount(cast<ConstantArrayType>(Ty));
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hekota wrote:

Yes, `Ty` should always be `ConstantArrayType` here. In case it is not, the `assert` in `cast` will validate that.

https://github.com/llvm/llvm-project/pull/152454