[CIR][Lowering][NFC] Expose cir::prepareTypeConverter()

Export this function so it can be used by other projects.

Author: keryell

clang/include/clang/CIR/LowerToMLIR.h

@@ -19,6 +19,8 @@ namespace cir {
 void populateCIRLoopToSCFConversionPatterns(mlir::RewritePatternSet &patterns,
                                             mlir::TypeConverter &converter);
 
+mlir::TypeConverter prepareTypeConverter();
+
 mlir::ModuleOp
 lowerFromCIRToMLIRToLLVMDialect(mlir::ModuleOp theModule,
                                 mlir::MLIRContext *mlirCtx = nullptr);

clang/lib/CIR/Lowering/ThroughMLIR/LowerCIRToMLIR.cpp

@@ -1374,7 +1374,7 @@ void populateCIRToMLIRConversionPatterns(mlir::RewritePatternSet &patterns,
                                                         patterns.getContext());
 }
 
-static mlir::TypeConverter prepareTypeConverter() {
+mlir::TypeConverter prepareTypeConverter() {
   mlir::TypeConverter converter;
   converter.addConversion([&](cir::PointerType type) -> mlir::Type {
     auto ty = convertTypeForMemory(converter, type.getPointee());