[mlir][Pass] Enable the option for reproducer generation without crashing

This patch adds API `makeReproducer` and cl::opt flag
--mlir-generate-reproducer=<filename> in order to allow for mlir
reproducer dumps even when the pipeline doesn't crash.

This will be useful for frameworks and runtimes that use MLIR where it is
needed to reproduce the pipeline behavior for reasons outside of diagnosing
crashes. An example is for diagnosing performance issues using offline tools,
where being able to dump the reproducer from a runtime compiler would be
helpful.

Author: plotfi

mlir/include/mlir/Pass/PassManager.h

@@ -222,6 +222,12 @@ struct ReproducerStream {
 using ReproducerStreamFactory =
     std::function<std::unique_ptr<ReproducerStream>(std::string &error)>;
 
+std::string
+makeReproducer(StringRef anchorName,
+               const llvm::iterator_range<OpPassManager::pass_iterator> &passes,
+               Operation *op, StringRef outputFile, bool disableThreads = false,
+               bool verifyPasses = false);
+
 /// The main pass manager and pipeline builder.
 class PassManager : public OpPassManager {
 public:

mlir/include/mlir/Tools/mlir-opt/MlirOptMain.h

@@ -173,6 +173,9 @@ class MlirOptMainConfig {
   }
   bool shouldVerifyRoundtrip() const { return verifyRoundtripFlag; }
 
+  /// Reproducer file generation (no crash required).
+  StringRef getReproducerFilename() const { return generateReproducerFileFlag; }
+
 protected:
   /// Allow operation with no registered dialects.
   /// This option is for convenience during testing only and discouraged in
@@ -228,6 +231,9 @@ class MlirOptMainConfig {
 
   /// Verify that the input IR round-trips perfectly.
   bool verifyRoundtripFlag = false;
+
+  /// The reproducer output filename (no crash required).
+  std::string generateReproducerFileFlag = "";
 };
 
 /// This defines the function type used to setup the pass manager. This can be

mlir/lib/Pass/PassCrashRecovery.cpp

@@ -440,6 +440,25 @@ makeReproducerStreamFactory(StringRef outputFile) {
   };
 }
 
+void printAsTextualPipeline(
+    raw_ostream &os, StringRef anchorName,
+    const llvm::iterator_range<OpPassManager::pass_iterator> &passes);
+
+std::string mlir::makeReproducer(
+    StringRef anchorName,
+    const llvm::iterator_range<OpPassManager::pass_iterator> &passes,
+    Operation *op, StringRef outputFile, bool disableThreads,
+    bool verifyPasses) {
+
+  std::string description;
+  std::string pipelineStr;
+  llvm::raw_string_ostream passOS(pipelineStr);
+  ::printAsTextualPipeline(passOS, anchorName, passes);
+  appendReproducer(description, op, makeReproducerStreamFactory(outputFile),
+                   pipelineStr, disableThreads, verifyPasses);
+  return description;
+}
+
 void PassManager::enableCrashReproducerGeneration(StringRef outputFile,
                                                   bool genLocalReproducer) {
   enableCrashReproducerGeneration(makeReproducerStreamFactory(outputFile),

mlir/lib/Tools/mlir-opt/MlirOptMain.cpp

@@ -151,6 +151,16 @@ struct MlirOptMainConfigCLOptions : public MlirOptMainConfig {
 
     static cl::list<std::string> passPlugins(
         "load-pass-plugin", cl::desc("Load passes from plugin library"));
+
+    static cl::opt<std::string, /*ExternalStorage=*/true>
+        generateReproducerFile(
+            "mlir-generate-reproducer",
+            llvm::cl::desc(
+                "Generate an mlir reproducer at the provided filename"
+                " (no crash required)"),
+            cl::location(generateReproducerFileFlag), cl::init(""),
+            cl::value_desc("filename"));
+
     /// Set the callback to load a pass plugin.
     passPlugins.setCallback([&](const std::string &pluginPath) {
       auto plugin = PassPlugin::load(pluginPath);
@@ -384,6 +394,14 @@ performActions(raw_ostream &os,
   if (failed(pm.run(*op)))
     return failure();
 
+  // Generate reproducers if requested
+  if (!config.getReproducerFilename().empty()) {
+    StringRef anchorName = pm.getAnyOpAnchorName();
+    const auto &passes = pm.getPasses();
+    makeReproducer(anchorName, passes, op.get(),
+                   config.getReproducerFilename());
+  }
+
   // Print the output.
   TimingScope outputTiming = timing.nest("Output");
   if (config.shouldEmitBytecode()) {

mlir/test/Pass/crashless-reproducer.mlir

@@ -0,0 +1,10 @@
+// RUN: mlir-opt %s -pass-pipeline='builtin.module(builtin.module(test-module-pass))' --mlir-generate-reproducer=%t -verify-diagnostics
+// RUN: cat %t | FileCheck -check-prefix=REPRO %s
+
+module @inner_mod1 {
+  module @foo {}
+}
+
+// REPRO: module @inner_mod1
+// REPRO: module @foo {
+// REPRO: pipeline: "builtin.module(any(builtin.module(test-module-pass)))"