[mlir] Add asserts when changing various MLIRContext configurations

[rriddle]

Summary

This helps to prevent tsan failures when users inadvertantly mutate the
context in a non-safe way.

[mehdi_amini]

Thanks!

[nicolasvasilache]

mlir/lib/IR/MLIRContext.cpp

361

I have a general question here on the registration requirements with nested passes.

Is there a good rule of thumb for dependent dialects, external models and dynamically injected ops mixed with nested passes?
It seems that a mechanism to declare dependent passes would be a good QoL improvement: it does not seem manageable for nested pass writers to have to manually add registration for everything in dependent passes.

Am I missing something?

[mehdi_amini]

mlir/lib/IR/MLIRContext.cpp

361

Dependent dialects is supposed to be handle recursively, which admittedly can be tricky sometimes. I think the IREE HAL handles it properly as an example: https://github.com/google/iree/blob/main/iree/compiler/Dialect/HAL/Transforms/TranslateExecutables.cpp#L46-L53

External models are supposed to be injected by IR producers, if this is part of a nested pass, the pass that nest this can handle this in getDependentDialects() as well.

mlir/include/mlir/IR/DialectRegistry.h

struct Extension : public DialectExtension<Extension, DialectsT...> {
       void apply(MLIRContext *context, DialectsT *...dialects) const final {
         extensionFn(context, dialects...);
       }
       ExtensionFnT extensionFn;
     };
     addExtension(std::make_unique<Extension>(std::move(extensionFn)));
   }
 
+  /// Returns true if the current registry is a subset of 'rhs', i.e. if 'rhs'
+  /// contains all of the components of this registry.
+  bool isSubsetOf(const DialectRegistry &rhs) const;
+
 private:
   MapTy registry;
   std::vector<std::unique_ptr<DialectExtensionBase>> extensions;
 };
 
 } // namespace mlir
 
 #endif // MLIR_IR_DIALECTREGISTRY_H

mlir/lib/IR/Dialect.cpp

for (StringRef dialectName : dialectNames) {
       requiredDialects.push_back(loadedDialect);
     }
     extension.apply(ctx, requiredDialects);
   };
 
   for (const auto &extension : extensions)
     applyExtension(*extension);
 }
+
+bool DialectRegistry::isSubsetOf(const DialectRegistry &rhs) const {
+  // Treat any extensions conservatively.
+  if (!extensions.empty())
+    return false;
+  // Check that the current dialects fully overlap with the dialects in 'rhs'.
+  return llvm::all_of(
+      registry, [&](const auto &it) { return rhs.registry.count(it.first); });
+}

mlir/lib/IR/MLIRContext.cpp

 /// Returns the diagnostic engine for this context.
 DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
 
 //===----------------------------------------------------------------------===//
 // Dialect and Operation Registration
 //===----------------------------------------------------------------------===//
 
 void MLIRContext::appendDialectRegistry(const DialectRegistry &registry) {
+  if (registry.isSubsetOf(impl->dialectsRegistry))
+    return;
+
+  assert(impl->multiThreadedExecutionContext == 0 &&
+         "appending to the MLIRContext dialect registry while in a "
+         "multi-threaded execution context");
   registry.appendTo(impl->dialectsRegistry);
 
   // For the already loaded dialects, apply any possible extensions immediately.
   registry.applyExtensions(this);
 }
 
 const DialectRegistry &MLIRContext::getDialectRegistry() {
   return impl->dialectsRegistry;
llvm::hash_code MLIRContext::getRegistryHash() {
   return hash;
 }
 
 bool MLIRContext::allowsUnregisteredDialects() {
   return impl->allowUnregisteredDialects;
 }
 
 void MLIRContext::allowUnregisteredDialects(bool allowing) {
+  assert(impl->multiThreadedExecutionContext == 0 &&
+         "changing MLIRContext `allow-unregistered-dialects` configuration "
+         "while in a multi-threaded execution context");
   impl->allowUnregisteredDialects = allowing;
 }
 
 /// Return true if multi-threading is enabled by the context.
 bool MLIRContext::isMultithreadingEnabled() {
   return impl->threadingIsEnabled && llvm::llvm_is_multithreaded();
 }
 
 /// Set the flag specifying if multi-threading is disabled by the context.
 void MLIRContext::disableMultithreading(bool disable) {
   // This API can be overridden by the global debugging flag
   // --mlir-disable-threading
   if (isThreadingGloballyDisabled())
     return;
+  assert(impl->multiThreadedExecutionContext == 0 &&
+         "changing MLIRContext `disable-threading` configuration while "
+         "in a multi-threaded execution context");
 
   impl->threadingIsEnabled = !disable;
 
   // Update the threading mode for each of the uniquers.
   impl->affineUniquer.disableMultithreading(disable);
   impl->attributeUniquer.disableMultithreading(disable);
   impl->typeUniquer.disableMultithreading(disable);
 

 /// Operation::emit.
 bool MLIRContext::shouldPrintOpOnDiagnostic() {
   return impl->printOpOnDiagnostic;
 }
 
 /// Set the flag specifying if we should attach the operation to diagnostics
 /// emitted via Operation::emit.
 void MLIRContext::printOpOnDiagnostic(bool enable) {
+  assert(impl->multiThreadedExecutionContext == 0 &&
+         "changing MLIRContext `print-op-on-diagnostic` configuration while in "
+         "a multi-threaded execution context");
   impl->printOpOnDiagnostic = enable;
 }
 
 /// Return true if we should attach the current stacktrace to diagnostics when
 /// emitted.
 bool MLIRContext::shouldPrintStackTraceOnDiagnostic() {
   return impl->printStackTraceOnDiagnostic;
 }
 
 /// Set the flag specifying if we should attach the current stacktrace when
 /// emitting diagnostics.
 void MLIRContext::printStackTraceOnDiagnostic(bool enable) {
+  assert(impl->multiThreadedExecutionContext == 0 &&
+         "changing MLIRContext `print-stacktrace-on-diagnostic` configuration "
+         "while in a multi-threaded execution context");
   impl->printStackTraceOnDiagnostic = enable;
 }
 
 /// Return information about all registered operations.
 ArrayRef<RegisteredOperationName> MLIRContext::getRegisteredOperations() {
   return impl->sortedRegisteredOperations;
 }
 

mlir/lib/Reducer/OptReductionPass.cpp

 void OptReductionPass::runOnOperation() {
   LLVM_DEBUG(llvm::dbgs() << "\nOptimization Reduction pass: ");
 
   Tester test(testerName, testerArgs);
 
   ModuleOp module = this->getOperation();
   ModuleOp moduleVariant = module.clone();
 
-  PassManager passManager(module.getContext());
+  OpPassManager passManager("builtin.module");
   if (failed(parsePassPipeline(optPass, passManager))) {
     module.emitError() << "\nfailed to parse pass pipeline";
     return signalPassFailure();
   }
 
   std::pair<Tester::Interestingness, int> original = test.isInteresting(module);
   if (original.first != Tester::Interestingness::True) {
     module.emitError() << "\nthe original input is not interested";
     return signalPassFailure();
   }
 
-  if (failed(passManager.run(moduleVariant))) {
+  // Temporarily push the variant under the main module and execute the pipeline
+  // on it.
+  module.getBody()->push_back(moduleVariant);
+  LogicalResult pipelineResult = runPipeline(passManager, moduleVariant);
+  moduleVariant->remove();
+
+  if (failed(pipelineResult)) {
     module.emitError() << "\nfailed to run pass pipeline";
     return signalPassFailure();
   }
 
   std::pair<Tester::Interestingness, int> reduced =
       test.isInteresting(moduleVariant);
 
   if (reduced.first == Tester::Interestingness::True &&

mlir/test/lib/Dialect/Linalg/TestLinalgFusionTransforms.cpp

struct TestLinalgGreedyFusion
   }
   void runOnOperation() override {
     MLIRContext *context = &getContext();
     RewritePatternSet patterns =
         linalg::getLinalgTilingCanonicalizationPatterns(context);
     patterns.add<ExtractSliceOfPadTensorSwapPattern>(context);
     scf::populateSCFForLoopCanonicalizationPatterns(patterns);
     FrozenRewritePatternSet frozenPatterns(std::move(patterns));
-    do {
-      (void)applyPatternsAndFoldGreedily(getOperation(), frozenPatterns);
-      PassManager pm(context);
-      pm.addPass(createLoopInvariantCodeMotionPass());
-      pm.addPass(createCanonicalizerPass());
-      pm.addPass(createCSEPass());
-      LogicalResult res = pm.run(getOperation()->getParentOfType<ModuleOp>());
-      if (failed(res))
+    OpPassManager pm(FuncOp::getOperationName());
+    do {
+      (void)applyPatternsAndFoldGreedily(getOperation(), frozenPatterns);
+      if (failed(runPipeline(pm, getOperation())))
         this->signalPassFailure();
     } while (succeeded(fuseLinalgOpsGreedily(getOperation())));
   }
 };
 
 /// Pass to test tile and fuse of sequence of operations. Intended only for
 /// testing.
 struct TestLinalgTileAndFuseSequencePass