Add an MLIR "pattern catalog" generator.

This PR adds a new cmake build option MLIR_ENABLE_CATALOG_GENERATOR.
When enabled, it attaches a listener to all RewritePatterns that emits
the name of the operation being modified to a special file. When the
MLIR test suite is run, these files can be combined into an index
linking operations to the patterns that insert, modify, or replace them.
This index is intended to be used to create a website that allows one
to look up patterns from an operation name.

Author: j2kun

mlir/CMakeLists.txt

@@ -202,6 +202,24 @@ if(MLIR_ENABLE_BINDINGS_PYTHON)
   mlir_configure_python_dev_packages()
 endif()
 
+#-------------------------------------------------------------------------------
+# MLIR Pattern Catalog Generator Configuration
+# Requires:
+#   RTTI to be enabled (set with -DLLVM_ENABLE_RTTI=ON)
+# When enabled, causes all rewriter patterns to dump their type names and the
+# names of affected operations, which can be used to build a search index
+# mapping operations to patterns.
+#-------------------------------------------------------------------------------
+
+set(MLIR_ENABLE_CATALOG_GENERATOR 0 CACHE BOOL
+       "Enables construction of a catalog of rewrite patterns.")
+
+if (MLIR_ENABLE_CATALOG_GENERATOR)
+  message(STATUS "Enabling MLIR pattern catalog generator")
+  add_definitions(-DMLIR_ENABLE_CATALOG_GENERATOR)
+  add_definitions(-DLLVM_ENABLE_RTTI)
+endif()
+
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
 include_directories(BEFORE
@@ -322,3 +340,4 @@ endif()
 if(MLIR_STANDALONE_BUILD)
   llvm_distribution_add_targets()
 endif()
+

mlir/cmake/modules/MLIRConfig.cmake.in

@@ -16,6 +16,7 @@ set(MLIR_IRDL_TO_CPP_EXE "@MLIR_CONFIG_IRDL_TO_CPP_EXE@")
 set(MLIR_INSTALL_AGGREGATE_OBJECTS "@MLIR_INSTALL_AGGREGATE_OBJECTS@")
 set(MLIR_ENABLE_BINDINGS_PYTHON "@MLIR_ENABLE_BINDINGS_PYTHON@")
 set(MLIR_ENABLE_EXECUTION_ENGINE "@MLIR_ENABLE_EXECUTION_ENGINE@")
+set(MLIR_ENABLE_CATALOG_GENERATOR "@MLIR_ENABLE_CATALOG_GENERATOR@")
 
 set_property(GLOBAL PROPERTY MLIR_ALL_LIBS "@MLIR_ALL_LIBS@")
 set_property(GLOBAL PROPERTY MLIR_DIALECT_LIBS "@MLIR_DIALECT_LIBS@")

mlir/include/mlir/IR/PatternMatch.h

@@ -475,6 +475,80 @@ class RewriterBase : public OpBuilder {
     RewriterBase::Listener *rewriteListener;
   };
 
+  struct CatalogingListener : public RewriterBase::ForwardingListener {
+    CatalogingListener(OpBuilder::Listener *listener,
+                       const std::string &patternName, raw_ostream &os,
+                       std::mutex &writeMutex)
+        : RewriterBase::ForwardingListener(listener), patternName(patternName),
+          os(os), writeMutex(writeMutex) {}
+
+    void notifyOperationInserted(Operation *op, InsertPoint previous) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyOperationInserted"
+           << " | " << op->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyOperationInserted(op, previous);
+    }
+
+    void notifyOperationModified(Operation *op) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyOperationModified"
+           << " | " << op->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyOperationModified(op);
+    }
+
+    void notifyOperationReplaced(Operation *op, Operation *newOp) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyOperationReplaced (with op)"
+           << " | " << op->getName() << " | " << newOp->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyOperationReplaced(op, newOp);
+    }
+
+    void notifyOperationReplaced(Operation *op,
+                                 ValueRange replacement) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyOperationReplaced (with values)"
+           << " | " << op->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyOperationReplaced(op, replacement);
+    }
+
+    void notifyOperationErased(Operation *op) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyOperationErased"
+           << " | " << op->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyOperationErased(op);
+    }
+
+    void notifyPatternBegin(const Pattern &pattern, Operation *op) override {
+      {
+        std::lock_guard<std::mutex> lock(writeMutex);
+        os << patternName << " | notifyPatternBegin"
+           << " | " << op->getName() << "\n";
+        os.flush();
+      }
+      ForwardingListener::notifyPatternBegin(pattern, op);
+    }
+
+  private:
+    const std::string &patternName;
+    raw_ostream &os;
+    std::mutex &writeMutex;
+  };
+
   /// Move the blocks that belong to "region" before the given position in
   /// another region "parent". The two regions must be different. The caller
   /// is responsible for creating or updating the operation transferring flow

mlir/lib/Rewrite/PatternApplicator.cpp

@@ -15,8 +15,19 @@
 #include "ByteCode.h"
 #include "llvm/Support/Debug.h"
 
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cxxabi.h>
+#include <mutex>
+#endif
+
 #define DEBUG_TYPE "pattern-application"
 
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+static std::mutex catalogWriteMutex;
+#endif
+
 using namespace mlir;
 using namespace mlir::detail;
 
@@ -152,6 +163,16 @@ LogicalResult PatternApplicator::matchAndRewrite(
   unsigned anyIt = 0, anyE = anyOpPatterns.size();
   unsigned pdlIt = 0, pdlE = pdlMatches.size();
   LogicalResult result = failure();
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+  std::error_code ec;
+  llvm::raw_fd_ostream catalogOs("pattern_catalog.txt", ec,
+                                 llvm::sys::fs::OF_Append);
+  if (ec) {
+    op->emitError("Failed to open pattern catalog file: " + ec.message());
+    return failure();
+  }
+#endif
+
   do {
     // Find the next pattern with the highest benefit.
     const Pattern *bestPattern = nullptr;
@@ -206,14 +227,38 @@ LogicalResult PatternApplicator::matchAndRewrite(
           } else {
             LLVM_DEBUG(llvm::dbgs() << "Trying to match \""
                                     << bestPattern->getDebugName() << "\"\n");
-
             const auto *pattern =
                 static_cast<const RewritePattern *>(bestPattern);
-            result = pattern->matchAndRewrite(op, rewriter);
 
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+            OpBuilder::Listener *oldListener = rewriter.getListener();
+            int status;
+            const char *mangledPatternName = typeid(*pattern).name();
+            char *demangled = abi::__cxa_demangle(mangledPatternName, nullptr,
+                                                  nullptr, &status);
+            std::string demangledPatternName;
+            if (status == 0 && demangled) {
+              demangledPatternName = demangled;
+              free(demangled);
+            } else {
+              // Fallback in case demangling fails.
+              demangledPatternName = mangledPatternName;
+            }
+
+            RewriterBase::CatalogingListener *catalogingListener =
+                new RewriterBase::CatalogingListener(
+                    oldListener, demangledPatternName, catalogOs,
+                    catalogWriteMutex);
+            rewriter.setListener(catalogingListener);
+#endif
+            result = pattern->matchAndRewrite(op, rewriter);
             LLVM_DEBUG(llvm::dbgs()
                        << "\"" << bestPattern->getDebugName() << "\" result "
                        << succeeded(result) << "\n");
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+            rewriter.setListener(oldListener);
+            delete catalogingListener;
+#endif
           }
 
           // Process the result of the pattern application.

utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel

@@ -44,6 +44,7 @@ expand_template(
         "@MLIR_ENABLE_SPIRV_CPU_RUNNER@": "0",
         "@MLIR_ENABLE_VULKAN_RUNNER@": "0",
         "@MLIR_ENABLE_BINDINGS_PYTHON@": "0",
+        "@MLIR_ENABLE_CATALOG_GENERATOR@": "0",
         "@MLIR_RUN_AMX_TESTS@": "0",
         "@MLIR_RUN_ARM_SVE_TESTS@": "0",
         "@MLIR_RUN_ARM_SME_TESTS@": "0",