[clang] [CIR] Add metadata type, attributes and metadata_as_value op. (PR #204190)

[via cfe-commits]

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@@ -464,6 +464,21 @@ class CIRGenBuilderTy : public cir::CIRBaseBuilderTy {
     return cir::ConstantOp::create(*this, loc, cir::ZeroAttr::get(ty));
   }
 
+  //===--------------------------------------------------------------------===//
+  // Metadata creation helpers
+  //===--------------------------------------------------------------------===//
+  cir::MDStringAttr getMDStringAttr(llvm::StringRef str) {
+    return cir::MDStringAttr::get(getContext(), getStringAttr(str));
+  }
+
+  cir::MDNodeAttr getMDNodeAttr(llvm::ArrayRef<mlir::Attribute> operands) {
+    return cir::MDNodeAttr::get(getContext(), operands);
+  }
+
+  mlir::Value createMetadataAsValue(mlir::Location loc, mlir::Attribute md) {
+    return cir::MetadataAsValueOp::create(*this, loc, md);
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skc7 wrote:

Both create forms exist in the generated `CIROps.cpp.inc`: the type-omitting one (`create(OpBuilder&, Location, Attribute)`) infers the fixed `!cir.metadata` result via `inferReturnTypes`, and the explicit-type one (`create(OpBuilder&, Location, Type, Attribute)`) is used where a Type is already in hand. `createMetadataAsValue` uses the former. `materializeConstant` uses the latter. Both build the same op.

https://github.com/llvm/llvm-project/pull/204190