[clang] [CIR] Call code gen; create empty cir.func op (PR #113483)

[Schrodinger ZHU Yifan via cfe-commits]

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@@ -16,4 +16,50 @@
 
 include "clang/CIR/Dialect/IR/CIRDialect.td"
 
+include "mlir/Interfaces/ControlFlowInterfaces.td"
+include "mlir/Interfaces/FunctionInterfaces.td"
+include "mlir/Interfaces/InferTypeOpInterface.td"
+include "mlir/Interfaces/LoopLikeInterface.td"
+include "mlir/Interfaces/MemorySlotInterfaces.td"
+include "mlir/Interfaces/SideEffectInterfaces.td"
+
+include "mlir/IR/BuiltinAttributeInterfaces.td"
+include "mlir/IR/EnumAttr.td"
+include "mlir/IR/SymbolInterfaces.td"
+include "mlir/IR/CommonAttrConstraints.td"
+
+//===----------------------------------------------------------------------===//
+// CIR Ops
+//===----------------------------------------------------------------------===//
+
+class LLVMLoweringInfo {
+  string llvmOp = "";
+}
+
+class CIR_Op<string mnemonic, list<Trait> traits = []> :
+    Op<CIR_Dialect, mnemonic, traits>, LLVMLoweringInfo;
+
+//===----------------------------------------------------------------------===//
+// FuncOp
+//===----------------------------------------------------------------------===//
+
+// For starters, cir.func has only name, nothing else.  The other properties
+// of a function will be added over time as more of ClangIR is upstreamed.
+
+def FuncOp : CIR_Op<"func"> {
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SchrodingerZhu wrote:

Maybe mention that some traits are to be added

https://github.com/llvm/llvm-project/pull/113483