[llvm] [mlir] Add an MLIR "pattern catalog" generator (PR #146228)

Jeremy Kun via llvm-commits llvm-commits at lists.llvm.org
Sat Jun 28 09:39:39 PDT 2025


https://github.com/j2kun created https://github.com/llvm/llvm-project/pull/146228

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.

>From e0f3b63a761b82d21c3dd09f6804f2644966a5da Mon Sep 17 00:00:00 2001
From: Jeremy Kun <j2kun at users.noreply.github.com>
Date: Sun, 27 Apr 2025 23:13:41 -0700
Subject: [PATCH] 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.
---
 mlir/CMakeLists.txt                           | 19 +++++
 mlir/cmake/modules/MLIRConfig.cmake.in        |  1 +
 mlir/include/mlir/IR/PatternMatch.h           | 74 +++++++++++++++++++
 mlir/lib/Rewrite/PatternApplicator.cpp        | 49 +++++++++++-
 .../mlir/test/BUILD.bazel                     |  1 +
 5 files changed, 142 insertions(+), 2 deletions(-)

diff --git a/mlir/CMakeLists.txt b/mlir/CMakeLists.txt
index 44493b75b8a8c..bd30d94e1ccb4 100644
--- a/mlir/CMakeLists.txt
+++ b/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()
+
diff --git a/mlir/cmake/modules/MLIRConfig.cmake.in b/mlir/cmake/modules/MLIRConfig.cmake.in
index 71f3e028b1e88..f4ae70a22b3d2 100644
--- a/mlir/cmake/modules/MLIRConfig.cmake.in
+++ b/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@")
diff --git a/mlir/include/mlir/IR/PatternMatch.h b/mlir/include/mlir/IR/PatternMatch.h
index 10cfe851765dc..141b3c6806ed8 100644
--- a/mlir/include/mlir/IR/PatternMatch.h
+++ b/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
diff --git a/mlir/lib/Rewrite/PatternApplicator.cpp b/mlir/lib/Rewrite/PatternApplicator.cpp
index 4a12183492fd4..c66aaf267881f 100644
--- a/mlir/lib/Rewrite/PatternApplicator.cpp
+++ b/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.
diff --git a/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel b/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel
index 23d89f41a3a45..281b2566304b0 100644
--- a/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel
+++ b/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",



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