diff --git a/mlir/include/mlir/Support/MlirOptMain.h b/mlir/include/mlir/Support/MlirOptMain.h
--- a/mlir/include/mlir/Support/MlirOptMain.h
+++ b/mlir/include/mlir/Support/MlirOptMain.h
@@ -27,11 +27,16 @@
 namespace mlir {
 class DialectRegistry;
 class PassPipelineCLParser;
+class PassManager;
+
+using PassPipelineFn = llvm::function_ref<LogicalResult(
+    PassManager &pm,
+    llvm::function_ref<LogicalResult(const Twine &)> errorHandler)>;
 
 /// Perform the core processing behind `mlir-opt`:
 /// - outputStream is the stream where the resulting IR is printed.
 /// - buffer is the in-memory file to parser and process.
-/// - passPipeline is the specification of the pipeline that will be applied.
+/// - pipelineFn is the callback to the pass pipeline that will be applied.
 /// - registry should contain all the dialects that can be parsed in the source.
 /// - splitInputFile will look for a "-----" marker in the input file, and load
 /// each chunk in an individual ModuleOp processed separately.
@@ -46,10 +51,9 @@
 ///   deprecated and will be removed soon.
 LogicalResult MlirOptMain(llvm::raw_ostream &outputStream,
                           std::unique_ptr<llvm::MemoryBuffer> buffer,
-                          const PassPipelineCLParser &passPipeline,
-                          DialectRegistry &registry, bool splitInputFile,
-                          bool verifyDiagnostics, bool verifyPasses,
-                          bool allowUnregisteredDialects,
+                          PassPipelineFn pipelineFn, DialectRegistry &registry,
+                          bool splitInputFile, bool verifyDiagnostics,
+                          bool verifyPasses, bool allowUnregisteredDialects,
                           bool preloadDialectsInContext = false);
 
 /// Implementation for tools like `mlir-opt`.
diff --git a/mlir/lib/Support/MlirOptMain.cpp b/mlir/lib/Support/MlirOptMain.cpp
--- a/mlir/lib/Support/MlirOptMain.cpp
+++ b/mlir/lib/Support/MlirOptMain.cpp
@@ -48,7 +48,7 @@
 static LogicalResult performActions(raw_ostream &os, bool verifyDiagnostics,
                                     bool verifyPasses, SourceMgr &sourceMgr,
                                     MLIRContext *context,
-                                    const PassPipelineCLParser &passPipeline) {
+                                    PassPipelineFn pipelineFn) {
   DefaultTimingManager tm;
   applyDefaultTimingManagerCLOptions(tm);
   TimingScope timing = tm.getRootScope();
@@ -77,8 +77,8 @@
     return failure();
   };
 
-  // Build the provided pipeline.
-  if (failed(passPipeline.addToPipeline(pm, errorHandler)))
+  // Callback to build the pipeline.
+  if (failed(pipelineFn(pm, errorHandler)))
     return failure();
 
   // Run the pipeline.
@@ -98,8 +98,8 @@
 processBuffer(raw_ostream &os, std::unique_ptr<MemoryBuffer> ownedBuffer,
               bool verifyDiagnostics, bool verifyPasses,
               bool allowUnregisteredDialects, bool preloadDialectsInContext,
-              const PassPipelineCLParser &passPipeline,
-              DialectRegistry &registry, llvm::ThreadPool &threadPool) {
+              PassPipelineFn pipelineFn, DialectRegistry &registry,
+              llvm::ThreadPool &threadPool) {
   // Tell sourceMgr about this buffer, which is what the parser will pick up.
   SourceMgr sourceMgr;
   sourceMgr.AddNewSourceBuffer(std::move(ownedBuffer), SMLoc());
@@ -122,7 +122,7 @@
   if (!verifyDiagnostics) {
     SourceMgrDiagnosticHandler sourceMgrHandler(sourceMgr, &context);
     return performActions(os, verifyDiagnostics, verifyPasses, sourceMgr,
-                          &context, passPipeline);
+                          &context, pipelineFn);
   }
 
   SourceMgrDiagnosticVerifierHandler sourceMgrHandler(sourceMgr, &context);
@@ -131,7 +131,7 @@
   // these actions succeed or fail, we only care what diagnostics they produce
   // and whether they match our expectations.
   (void)performActions(os, verifyDiagnostics, verifyPasses, sourceMgr, &context,
-                       passPipeline);
+                       pipelineFn);
 
   // Verify the diagnostic handler to make sure that each of the diagnostics
   // matched.
@@ -140,7 +140,7 @@
 
 LogicalResult mlir::MlirOptMain(raw_ostream &outputStream,
                                 std::unique_ptr<MemoryBuffer> buffer,
-                                const PassPipelineCLParser &passPipeline,
+                                PassPipelineFn pipelineFn,
                                 DialectRegistry &registry, bool splitInputFile,
                                 bool verifyDiagnostics, bool verifyPasses,
                                 bool allowUnregisteredDialects,
@@ -156,14 +156,14 @@
         [&](std::unique_ptr<MemoryBuffer> chunkBuffer, raw_ostream &os) {
           return processBuffer(os, std::move(chunkBuffer), verifyDiagnostics,
                                verifyPasses, allowUnregisteredDialects,
-                               preloadDialectsInContext, passPipeline, registry,
+                               preloadDialectsInContext, pipelineFn, registry,
                                threadPool);
         },
         outputStream);
 
   return processBuffer(outputStream, std::move(buffer), verifyDiagnostics,
                        verifyPasses, allowUnregisteredDialects,
-                       preloadDialectsInContext, passPipeline, registry,
+                       preloadDialectsInContext, pipelineFn, registry,
                        threadPool);
 }
 
@@ -266,9 +266,14 @@
     return failure();
   }
 
-  if (failed(MlirOptMain(output->os(), std::move(file), passPipeline, registry,
-                         splitInputFile, verifyDiagnostics, verifyPasses,
-                         allowUnregisteredDialects, preloadDialectsInContext)))
+  if (failed(MlirOptMain(
+          output->os(), std::move(file),
+          [&](PassManager &pm,
+              function_ref<LogicalResult(const Twine &)> errorHandler) {
+            return passPipeline.addToPipeline(pm, errorHandler);
+          },
+          registry, splitInputFile, verifyDiagnostics, verifyPasses,
+          allowUnregisteredDialects, preloadDialectsInContext)))
     return failure();
 
   // Keep the output file if the invocation of MlirOptMain was successful.