[clang] [CIR] Upstream support for string literals (PR #140796)

[Erich Keane via cfe-commits]

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@@ -26,6 +26,34 @@ class CIRGenBuilderTy : public cir::CIRBaseBuilderTy {
   CIRGenBuilderTy(mlir::MLIRContext &mlirContext, const CIRGenTypeCache &tc)
       : CIRBaseBuilderTy(mlirContext), typeCache(tc) {}
 
+  /// Get a cir::ConstArrayAttr for a string literal.
+  /// Note: This is different from what is returned by
+  /// mlir::Builder::getStringAttr() which is an mlir::StringAttr.
+  mlir::Attribute getString(llvm::StringRef str, mlir::Type eltTy,
+                            std::optional<size_t> size) {
+    size_t finalSize = size ? *size : str.size();
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erichkeane wrote:

```suggestion
    size_t finalSize = size.value_or(str.size());
```

https://github.com/llvm/llvm-project/pull/140796