[clang] [CIR] Build out AST consumer patterns to reach the entry point into CIRGen (PR #91007)

[Erich Keane via cfe-commits]

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@@ -0,0 +1,61 @@
+//===---- CIRGenAction.h - CIR Code Generation Frontend Action -*- C++ -*--===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_CIR_CIRGENACTION_H
+#define LLVM_CLANG_CIR_CIRGENACTION_H
+
+#include "clang/Frontend/FrontendAction.h"
+
+#include "mlir/IR/BuiltinOps.h"
+#include "mlir/IR/OwningOpRef.h"
+
+namespace mlir {
+class MLIRContext;
+class ModuleOp;
+} // namespace mlir
+
+namespace cir {
+class CIRGenConsumer;
+
+class CIRGenAction : public clang::ASTFrontendAction {
+public:
+  enum class OutputType {
+    EmitCIR,
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erichkeane wrote:

Whats the purpose here?  Do we anticipate a 2nd output type?  

https://github.com/llvm/llvm-project/pull/91007