[Mlir-commits] [mlir] [MLIR] Integrate LLVM Optimization Remarks Infrastructure (PR #152474)

Guray Ozen llvmlistbot at llvm.org
Thu Aug 7 04:19:58 PDT 2025


https://github.com/grypp updated https://github.com/llvm/llvm-project/pull/152474

>From 6d6d8966ac3918c8f60226eff617033d74a3d98c Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 7 Aug 2025 10:01:51 +0000
Subject: [PATCH 1/2] [MLIR] MLIR Integrate LLVM Optimization Remarks
 Infrastructure
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This patch hooks LLVM’s remarks infrastructure into MLIR.

* Disabled by default, zero-cost when off.
  Enable per context with `MLIRContext::setupOptimizationRemarks(...)`.
* YAML or bitstream output: via new `MLIRRemarkStreamer`
  (subclasses `llvm::remarks::RemarkStreamer`).
* Implements simple APIs for passes:

User-code can directly prints remarks like:
```
reportOptimizationPass(loc, categoryName, "MyPass")        << "vectorized";
reportOptimizationMiss(loc, categoryLoopUnroll, "MyPass",
                       "try increasing unroll factor")      << "...";
reportOptimizationFail(loc, categoryLoopUnroll, "MyPass")  << "...";
reportOptimizationAnalysis(loc, categoryLoopUnroll, "MyPass")
                       << "estimated trip count: " << tripCount;
```
---
 mlir/include/mlir/IR/MLIRContext.h |  15 +
 mlir/include/mlir/IR/Remarks.h     | 454 +++++++++++++++++++++++++++++
 mlir/lib/IR/CMakeLists.txt         |   6 +
 mlir/lib/IR/MLIRContext.cpp        |  35 +++
 mlir/lib/IR/Remarks.cpp            | 296 +++++++++++++++++++
 mlir/unittests/IR/CMakeLists.txt   |   1 +
 mlir/unittests/IR/RemarkTest.cpp   | 106 +++++++
 7 files changed, 913 insertions(+)
 create mode 100644 mlir/include/mlir/IR/Remarks.h
 create mode 100644 mlir/lib/IR/Remarks.cpp
 create mode 100644 mlir/unittests/IR/RemarkTest.cpp

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index ef8dab87f131a..ab8f4aed3fc79 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -32,6 +32,7 @@ class InFlightDiagnostic;
 class Location;
 class MLIRContextImpl;
 class RegisteredOperationName;
+class RemarkEngine;
 class StorageUniquer;
 class IRUnit;
 
@@ -212,6 +213,9 @@ class MLIRContext {
   /// Returns the diagnostic engine for this context.
   DiagnosticEngine &getDiagEngine();
 
+  /// Returns the remark engine for this context.
+  std::unique_ptr<RemarkEngine> &getRemarkEngine();
+
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
 
@@ -245,6 +249,14 @@ class MLIRContext {
   /// (attributes, operations, types, etc.).
   llvm::hash_code getRegistryHash();
 
+  /// Set up optimization remarks for the context.
+  void setupOptimizationRemarks(
+      StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
+      const std::optional<std::string> &categoryPassName = std::nullopt,
+      const std::optional<std::string> &categoryMissName = std::nullopt,
+      const std::optional<std::string> &categoryAnalysisName = std::nullopt,
+      const std::optional<std::string> &categoryFailedName = std::nullopt);
+
   //===--------------------------------------------------------------------===//
   // Action API
   //===--------------------------------------------------------------------===//
@@ -281,6 +293,9 @@ class MLIRContext {
   }
 
 private:
+  /// Set the remark engine for this context.
+  void setRemarkEngine(std::unique_ptr<RemarkEngine> engine);
+
   /// Return true if the given dialect is currently loading.
   bool isDialectLoading(StringRef dialectNamespace);
 
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
new file mode 100644
index 0000000000000..8f7e7a900e7f1
--- /dev/null
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -0,0 +1,454 @@
+//===- Remarks.h - MLIR Optimization Remark ----------------------*- C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines utilities for emitting optimization remarks.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_IR_REMARKS_H
+#define MLIR_IR_REMARKS_H
+
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/Remarks/Remark.h"
+#include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+#include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/MLIRContext.h"
+
+namespace mlir {
+
+/// Defines different remark kinds that can be used to categorize remarks.
+enum class RemarkKind {
+  OptimizationRemarkUnknown = 0,
+  OptimizationRemarkPass,
+  OptimizationRemarkMissed,
+  OptimizationRemarkFailure,
+  OptimizationRemarkAnalysis,
+};
+
+//===----------------------------------------------------------------------===//
+// Remark Base Class
+//===----------------------------------------------------------------------===//
+class RemarkBase : public llvm::DiagnosticInfo {
+
+public:
+  RemarkBase(RemarkKind remarkKind, DiagnosticSeverity severity,
+             const char *passName, StringRef remarkName, Location loc,
+             std::optional<StringRef> functionName = std::nullopt)
+      : llvm::DiagnosticInfo(makeLLVMKind(remarkKind),
+                             makeLLVMSeverity(severity)),
+        remarkKind(remarkKind), functionName(functionName), loc(loc),
+        passName(passName), remarkName(remarkName) {}
+
+  struct SetIsVerbose {};
+
+  struct SetExtraArgs {};
+
+  struct RemarkKeyValue {
+    std::string key;
+    std::string val;
+
+    explicit RemarkKeyValue(StringRef str = "") : key("String"), val(str) {}
+    RemarkKeyValue(StringRef key, Value value);
+    RemarkKeyValue(StringRef key, Type type);
+    RemarkKeyValue(StringRef key, StringRef s);
+    RemarkKeyValue(StringRef key, const char *s)
+        : RemarkKeyValue(key, StringRef(s)) {};
+    RemarkKeyValue(StringRef key, int n);
+    RemarkKeyValue(StringRef key, float n);
+    RemarkKeyValue(StringRef key, long n);
+    RemarkKeyValue(StringRef key, long long n);
+    RemarkKeyValue(StringRef key, unsigned n);
+    RemarkKeyValue(StringRef key, unsigned long n);
+    RemarkKeyValue(StringRef key, unsigned long long n);
+    RemarkKeyValue(StringRef key, bool b)
+        : key(key), val(b ? "true" : "false") {}
+  };
+
+  void insert(StringRef s);
+  void insert(RemarkKeyValue a);
+  void insert(SetIsVerbose v);
+  void insert(SetExtraArgs ea);
+
+  void print(llvm::DiagnosticPrinter &dp) const override;
+  void print() const;
+
+  virtual bool isEnabled() const = 0;
+  Location getLocation() const { return loc; }
+  llvm::remarks::RemarkLocation getRemarkLocation() const;
+  /// Diagnostic -> Remark
+  llvm::remarks::Remark generateRemark() const;
+
+  StringRef getFunction() const {
+    if (functionName)
+      return *functionName;
+    return "<unknown function>";
+  }
+  StringRef getPassName() const { return passName; }
+  StringRef getRemarkName() const { return remarkName; }
+  std::string getMsg() const;
+
+  bool isVerbose() const { return isVerboseRemark; }
+
+  ArrayRef<RemarkKeyValue> getArgs() const { return args; }
+
+  llvm::remarks::Type getRemarkType() const;
+
+protected:
+  /// Keeps the MLIR diagnostic kind, which is used to determine the
+  /// diagnostic kind in the LLVM remark streamer.
+  RemarkKind remarkKind;
+  /// Name of the convering function like interface
+  std::optional<std::string> functionName;
+
+  Location loc;
+  /// Name of the pass that triggers this report.
+  const char *passName;
+
+  /// Textual identifier for the remark (single-word, CamelCase). Can be used
+  /// by external tools reading the output file for optimization remarks to
+  /// identify the remark.
+  StringRef remarkName;
+
+  /// RemarkKeyValues collected via the streaming interface.
+  SmallVector<RemarkKeyValue, 4> args;
+
+  /// The remark is expected to be noisy.
+  bool isVerboseRemark = false;
+
+private:
+  /// Convert the MLIR diagnostic severity to LLVM diagnostic severity.
+  static llvm::DiagnosticSeverity
+  makeLLVMSeverity(DiagnosticSeverity severity) {
+    switch (severity) {
+    case DiagnosticSeverity::Note:
+      return llvm::DiagnosticSeverity::DS_Note;
+    case DiagnosticSeverity::Warning:
+      return llvm::DiagnosticSeverity::DS_Warning;
+    case DiagnosticSeverity::Error:
+      return llvm::DiagnosticSeverity::DS_Error;
+    case DiagnosticSeverity::Remark:
+      return llvm::DiagnosticSeverity::DS_Remark;
+    }
+    llvm_unreachable("Unknown diagnostic severity");
+  }
+  /// Convert the MLIR remark kind to LLVM diagnostic kind.
+  static llvm::DiagnosticKind makeLLVMKind(RemarkKind remarkKind) {
+    switch (remarkKind) {
+    case RemarkKind::OptimizationRemarkUnknown:
+      return llvm::DiagnosticKind::DK_Generic;
+    case RemarkKind::OptimizationRemarkPass:
+      return llvm::DiagnosticKind::DK_OptimizationRemark;
+    case RemarkKind::OptimizationRemarkMissed:
+      return llvm::DiagnosticKind::DK_OptimizationRemarkMissed;
+    case RemarkKind::OptimizationRemarkFailure:
+      return llvm::DiagnosticKind::DK_OptimizationFailure;
+    case RemarkKind::OptimizationRemarkAnalysis:
+      return llvm::DiagnosticKind::DK_OptimizationRemarkAnalysis;
+    }
+    llvm_unreachable("Unknown diagnostic kind");
+  }
+};
+
+// clang-format off
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     StringRef>
+        s) {
+  r.insert(s);
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::RemarkKeyValue>
+        a) {
+  r.insert(std::move(a));
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::SetIsVerbose>
+        v) {
+  r.insert(v);
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::SetExtraArgs>
+        ea) {
+  r.insert(ea);
+  return std::forward<RemarkT>(r);
+}
+// clang-format on
+
+//===----------------------------------------------------------------------===//
+// Shorthand aliases for different kinds of remarks.
+//===----------------------------------------------------------------------===//
+
+template <RemarkKind K, DiagnosticSeverity S>
+class OptRemarkBase final : public RemarkBase {
+public:
+  explicit OptRemarkBase(Location loc, StringRef passName, StringRef remarkName)
+      : RemarkBase(K, S, passName.data(), remarkName, loc) {}
+
+  bool isEnabled() const override { return true; }
+};
+
+using OptRemarkAnalysis = OptRemarkBase<RemarkKind::OptimizationRemarkAnalysis,
+                                        DiagnosticSeverity::Remark>;
+
+using OptRemarkPass = OptRemarkBase<RemarkKind::OptimizationRemarkPass,
+                                    DiagnosticSeverity::Remark>;
+
+using OptRemarkMissed = OptRemarkBase<RemarkKind::OptimizationRemarkMissed,
+                                      DiagnosticSeverity::Remark>;
+
+using OptRemarkFailure = OptRemarkBase<RemarkKind::OptimizationRemarkFailure,
+                                       DiagnosticSeverity::Remark>;
+
+class RemarkEngine;
+
+//===----------------------------------------------------------------------===//
+// InFlightRemark
+//===----------------------------------------------------------------------===//
+
+/// InFlightRemark is a RAII class that holds a reference to a RemarkBase
+/// instance and allows to build the remark using the << operator. The remark
+/// is emitted when the InFlightRemark instance is destroyed, which happens
+/// when the scope ends or when the InFlightRemark instance is moved.
+/// Similar to InFlightDiagnostic, but for remarks.
+class InFlightRemark {
+public:
+  explicit InFlightRemark(RemarkBase *diag) : remark(diag) {}
+  InFlightRemark(RemarkEngine &eng, RemarkBase *diag)
+      : owner(&eng), remark(diag) {}
+
+  InFlightRemark() = default; // empty ctor
+
+  template <typename T>
+  InFlightRemark &operator<<(T &&arg) {
+    if (remark)
+      *remark << std::forward<T>(arg);
+    return *this;
+  }
+
+  explicit operator bool() const { return remark != nullptr; }
+
+  ~InFlightRemark();
+
+  InFlightRemark(const InFlightRemark &) = delete;
+  InFlightRemark &operator=(const InFlightRemark &) = delete;
+  InFlightRemark(InFlightRemark &&) = default;
+  InFlightRemark &operator=(InFlightRemark &&) = default;
+
+private:
+  RemarkEngine *owner{nullptr};
+  std::unique_ptr<RemarkBase> remark;
+};
+
+//===----------------------------------------------------------------------===//
+// MLIR Remark Streamer
+//===----------------------------------------------------------------------===//
+
+class MLIRRemarkStreamer {
+  llvm::remarks::RemarkStreamer &remarkStreamer;
+
+public:
+  explicit MLIRRemarkStreamer(llvm::remarks::RemarkStreamer &remarkStreamer)
+      : remarkStreamer(remarkStreamer) {}
+
+  void streamOptimizationRemark(const RemarkBase &remark);
+};
+
+//===----------------------------------------------------------------------===//
+// Remark Engine (MLIR Context will own this class)
+//===----------------------------------------------------------------------===//
+
+class RemarkEngine {
+private:
+  /// The category for missed optimization remarks.
+  std::optional<llvm::Regex> missFilter;
+  /// The category for passed optimization remarks.
+  std::optional<llvm::Regex> passFilter;
+  /// The category for analysis remarks.
+  std::optional<llvm::Regex> analysisFilter;
+  /// The category for failed optimization remarks.
+  std::optional<llvm::Regex> failedFilter;
+  /// The output file for the remarks.
+  std::unique_ptr<llvm::ToolOutputFile> remarksFile;
+  /// The MLIR remark streamer that will be used to emit the remarks.
+  std::unique_ptr<MLIRRemarkStreamer> remarkStreamer;
+  std::unique_ptr<llvm::remarks::RemarkStreamer> llvmRemarkStreamer;
+  /// When is enabled, engine also prints remarks as mlir::emitRemarks.
+  bool printAsEmitRemarks;
+  /// The main MLIR remark streamer that will be used to emit the remarks.
+  MLIRRemarkStreamer *getLLVMRemarkStreamer() { return remarkStreamer.get(); }
+  const MLIRRemarkStreamer *getLLVMRemarkStreamer() const {
+    return remarkStreamer.get();
+  }
+  void
+  setLLVMRemarkStreamer(std::unique_ptr<MLIRRemarkStreamer> remarkStreamer) {
+    this->remarkStreamer = std::move(remarkStreamer);
+  }
+
+  /// Get the main MLIR remark streamer that will be used to emit the remarks.
+  llvm::remarks::RemarkStreamer *getMainRemarkStreamer() {
+    return llvmRemarkStreamer.get();
+  }
+  const llvm::remarks::RemarkStreamer *getMainRemarkStreamer() const {
+    return llvmRemarkStreamer.get();
+  }
+  /// Set the main remark streamer to be used by the engine.
+  void setMainRemarkStreamer(
+      std::unique_ptr<llvm::remarks::RemarkStreamer> mainRemarkStreamer) {
+    llvmRemarkStreamer = std::move(mainRemarkStreamer);
+  }
+
+  /// Return true if missed optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isMissedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if passed optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isPassedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if analysis optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isAnalysisOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if analysis optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isFailedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if any type of remarks are enabled for this pass.
+  bool isAnyRemarkEnabled(StringRef categoryName) const {
+    return (isMissedOptRemarkEnabled(categoryName) ||
+            isPassedOptRemarkEnabled(categoryName) ||
+            isFailedOptRemarkEnabled(categoryName) ||
+            isAnalysisOptRemarkEnabled(categoryName));
+  }
+
+  /// Emit a remark using the given maker function, which should return
+  /// a RemarkBase instance. The remark will be emitted using the main
+  /// remark streamer.
+  template <typename RemarkT, typename... Args>
+  InFlightRemark makeRemark(Args &&...args);
+
+  template <typename RemarkT>
+  InFlightRemark
+  emitIfEnabled(Location loc, StringRef passName, StringRef category,
+                bool (RemarkEngine::*isEnabled)(StringRef) const);
+
+public:
+  RemarkEngine() = delete;
+  /// Constructs Remark engine with optional category names
+  RemarkEngine(bool printAsEmitRemarks,
+               std::optional<std::string> categoryPassName = std::nullopt,
+               std::optional<std::string> categoryMissName = std::nullopt,
+               std::optional<std::string> categoryAnalysisName = std::nullopt,
+               std::optional<std::string> categoryFailedName = std::nullopt);
+
+  /// Destructor that will close the output file and reset the
+  /// main remark streamer.
+  ~RemarkEngine();
+
+  /// Setup the remark engine with the given output path and format.
+  llvm::Error initialize(StringRef outputPath, StringRef outputFormat);
+
+  /// Report a diagnostic remark.
+  void report(const RemarkBase &&diag);
+
+  /// Report a successful remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemark(Location loc, StringRef passName,
+                                        StringRef category);
+  /// Report a missed optimization remark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkMiss(Location loc, StringRef passName,
+                                            StringRef category);
+  /// Report a failed optimization remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkFailure(Location loc, StringRef passName,
+                                               StringRef category);
+  /// Report an analysis remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkAnalysis(Location loc,
+                                                StringRef passName,
+                                                StringRef category);
+};
+
+//===----------------------------------------------------------------------===//
+// Emitters
+//===----------------------------------------------------------------------===//
+
+using Suggestion = RemarkBase::RemarkKeyValue;
+inline Suggestion suggest(StringRef txt) { return {"Suggestion", txt}; }
+
+template <typename Fn, typename... Args>
+[[nodiscard]] inline InFlightRemark withEngine(Fn fn, Location loc,
+                                               Args &&...args) {
+  MLIRContext *ctx = loc->getContext();
+
+  auto &enginePtr = ctx->getRemarkEngine();
+
+  if (RemarkEngine *eng = enginePtr.get())
+    return (eng->*fn)(loc, std::forward<Args>(args)...);
+
+  return {};
+}
+
+/// Report an optimization remark that was passed.
+inline InFlightRemark reportOptimizationPass(Location loc, StringRef cat,
+                                             StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemark, loc, passName, cat);
+}
+
+/// Report an optimization remark that was missed.
+inline InFlightRemark reportOptimizationMiss(Location loc, StringRef cat,
+                                             StringRef passName,
+                                             StringRef suggestion) {
+  auto r =
+      withEngine(&RemarkEngine::emitOptimizationRemarkMiss, loc, passName, cat);
+  if (r)
+    r << suggest(suggestion);
+  return r;
+}
+/// Report an optimization failure remark.
+inline InFlightRemark reportOptimizationFail(Location loc, StringRef cat,
+                                             StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemarkFailure, loc, passName,
+                    cat);
+}
+
+/// Report an optimization analysis remark.
+inline InFlightRemark reportOptimizationAnalysis(Location loc, StringRef cat,
+                                                 StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemarkAnalysis, loc,
+                    passName, cat);
+}
+
+} // namespace mlir
+
+#endif // MLIR_IR_REMARKS_H
\ No newline at end of file
diff --git a/mlir/lib/IR/CMakeLists.txt b/mlir/lib/IR/CMakeLists.txt
index 3ef69cea18f0a..438e486f2ad4c 100644
--- a/mlir/lib/IR/CMakeLists.txt
+++ b/mlir/lib/IR/CMakeLists.txt
@@ -33,6 +33,7 @@ add_mlir_library(MLIRIR
   PatternMatch.cpp
   Region.cpp
   RegionKindInterface.cpp
+  Remarks.cpp
   SymbolTable.cpp
   TensorEncoding.cpp
   Types.cpp
@@ -69,5 +70,10 @@ add_mlir_library(MLIRIR
 
   LINK_LIBS PUBLIC
   MLIRSupport
+  
+  LINK_COMPONENTS
+    Remarks
+    Core
+    BitstreamReader  
   )
 
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 2d5381d43f863..5a37de1481eb9 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -25,12 +25,14 @@
 #include "mlir/IR/Location.h"
 #include "mlir/IR/OpImplementation.h"
 #include "mlir/IR/OperationSupport.h"
+#include "mlir/IR/Remarks.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/RWMutex.h"
@@ -133,6 +135,11 @@ class MLIRContextImpl {
   //===--------------------------------------------------------------------===//
   DiagnosticEngine diagEngine;
 
+  //===--------------------------------------------------------------------===//
+  // Remark
+  //===--------------------------------------------------------------------===//
+  std::unique_ptr<RemarkEngine> remarkEngine;
+
   //===--------------------------------------------------------------------===//
   // Options
   //===--------------------------------------------------------------------===//
@@ -387,6 +394,34 @@ bool MLIRContext::hasActionHandler() { return (bool)getImpl().actionHandler; }
 /// Returns the diagnostic engine for this context.
 DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
 
+//===----------------------------------------------------------------------===//
+// Remark Handlers
+//===----------------------------------------------------------------------===//
+
+/// Returns the remark engine for this context.
+void MLIRContext::setRemarkEngine(std::unique_ptr<RemarkEngine> engine) {
+  getImpl().remarkEngine = std::move(engine);
+}
+
+std::unique_ptr<RemarkEngine> &MLIRContext::getRemarkEngine() {
+  return getImpl().remarkEngine;
+}
+
+void MLIRContext::setupOptimizationRemarks(
+    StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
+    const std::optional<std::string> &categoryPassName,
+    const std::optional<std::string> &categoryMissName,
+    const std::optional<std::string> &categoryAnalysisName,
+    const std::optional<std::string> &categoryFailedName) {
+  auto engine = std::make_unique<RemarkEngine>(
+      printAsEmitRemarks, categoryPassName, categoryMissName,
+      categoryAnalysisName, categoryFailedName);
+  llvm::Error e = engine->initialize(outputPath, outputFormat);
+  if (e)
+    llvm::report_fatal_error("Failed to initialize remark engine");
+  setRemarkEngine(std::move(engine));
+}
+
 //===----------------------------------------------------------------------===//
 // Dialect and Operation Registration
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
new file mode 100644
index 0000000000000..4d2aa95236f68
--- /dev/null
+++ b/mlir/lib/IR/Remarks.cpp
@@ -0,0 +1,296 @@
+//===- Remarks.cpp - MLIR Remarks ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/IR/Remarks.h"
+
+#include "mlir/IR/Attributes.h"
+#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/Value.h"
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/LLVMRemarkStreamer.h"
+#include "llvm/Remarks/RemarkFormat.h"
+#include "llvm/Support/FileSystem.h"
+
+using namespace mlir;
+
+//------------------------------------------------------------------------------
+// RemarkBase
+//------------------------------------------------------------------------------
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Value value)
+    : key(std::string(key)) {
+
+  llvm::raw_string_ostream rss(val);
+  rss << value;
+}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Type type)
+    : key(std::string(key)) {
+  llvm::raw_string_ostream os(val);
+  os << type;
+}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, StringRef s)
+    : key(std::string(key)), val(s.str()) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, int n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, float n)
+    : key(std::string(key)), val(std::to_string(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long long n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+void RemarkBase::print(llvm::DiagnosticPrinter &dp) const {
+  std::string str;
+  llvm::raw_string_ostream os(str);
+  getLocation()->print(os);
+  os.flush();
+  dp << str << ": " << getMsg();
+}
+
+void RemarkBase::print() const { emitError(getLocation(), getMsg()); }
+
+void RemarkBase::insert(StringRef s) { args.emplace_back(s); }
+
+void RemarkBase::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+
+void RemarkBase::insert(SetIsVerbose v) { isVerboseRemark = true; }
+
+std::string RemarkBase::getMsg() const {
+  std::string str;
+  llvm::raw_string_ostream rss(str);
+  for (const RemarkBase::RemarkKeyValue &arg :
+       llvm::make_range(args.begin(), args.end()))
+    rss << arg.val;
+  return str;
+}
+
+llvm::remarks::Type RemarkBase::getRemarkType() const {
+  switch (remarkKind) {
+  case RemarkKind::OptimizationRemarkUnknown:
+    return llvm::remarks::Type::Unknown;
+  case RemarkKind::OptimizationRemarkPass:
+    return llvm::remarks::Type::Passed;
+  case RemarkKind::OptimizationRemarkMissed:
+    return llvm::remarks::Type::Missed;
+  case RemarkKind::OptimizationRemarkFailure:
+    return llvm::remarks::Type::Failure;
+  case RemarkKind::OptimizationRemarkAnalysis:
+    return llvm::remarks::Type::Analysis;
+  }
+  llvm_unreachable("Unknown remark kind");
+}
+
+llvm::remarks::RemarkLocation RemarkBase::getRemarkLocation() const {
+  if (auto flc = dyn_cast<FileLineColLoc>(getLocation())) {
+    auto *buf = new std::string("./" + flc.getFilename().str());
+    return {*buf, flc.getLine(), flc.getColumn()};
+  }
+  return {"<unknown file>", 0, 0};
+}
+
+llvm::remarks::Remark RemarkBase::generateRemark() const {
+  llvm::remarks::Remark r; // The result.
+  r.RemarkType = getRemarkType();
+  r.PassName = getPassName();
+  r.RemarkName = getRemarkName();
+  r.FunctionName = getFunction();
+  r.Loc = getRemarkLocation();
+  for (const RemarkBase::RemarkKeyValue &arg : getArgs()) {
+    r.Args.emplace_back();
+    r.Args.back().Key = arg.key;
+    r.Args.back().Val = arg.val;
+  }
+  return r;
+}
+
+//===----------------------------------------------------------------------===//
+// InFlightRemark
+//===----------------------------------------------------------------------===//
+
+InFlightRemark::~InFlightRemark() {
+  if (remark)
+    if (owner) {
+      owner->report(std::move(*remark));
+    }
+  owner = nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Remark Engine
+//===----------------------------------------------------------------------===//
+
+template <typename RemarkT, typename... Args>
+InFlightRemark RemarkEngine::makeRemark(Args &&...args) {
+  return InFlightRemark(*this, new RemarkT(std::forward<Args>(args)...));
+}
+
+template <typename RemarkT>
+InFlightRemark
+RemarkEngine::emitIfEnabled(Location loc, StringRef passName,
+                            StringRef category,
+                            bool (RemarkEngine::*isEnabled)(StringRef) const) {
+  return (this->*isEnabled)(category)
+             ? makeRemark<RemarkT>(loc, category, passName)
+             : InFlightRemark{};
+}
+
+bool RemarkEngine::isMissedOptRemarkEnabled(StringRef categoryName) const {
+  return missFilter && missFilter->match(categoryName);
+}
+
+bool RemarkEngine::isPassedOptRemarkEnabled(StringRef categoryName) const {
+  return passFilter && passFilter->match(categoryName);
+}
+
+bool RemarkEngine::isAnalysisOptRemarkEnabled(StringRef categoryName) const {
+  return analysisFilter && analysisFilter->match(categoryName);
+}
+
+bool RemarkEngine::isFailedOptRemarkEnabled(StringRef categoryName) const {
+  return failedFilter && failedFilter->match(categoryName);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemark(Location loc,
+                                                    StringRef passName,
+                                                    StringRef category) {
+  return emitIfEnabled<OptRemarkPass>(loc, passName, category,
+                                      &RemarkEngine::isPassedOptRemarkEnabled);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemarkMiss(Location loc,
+                                                        StringRef passName,
+                                                        StringRef category) {
+  return emitIfEnabled<OptRemarkMissed>(
+      loc, passName, category, &RemarkEngine::isMissedOptRemarkEnabled);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemarkFailure(Location loc,
+                                                           StringRef passName,
+                                                           StringRef category) {
+  return emitIfEnabled<OptRemarkFailure>(
+      loc, passName, category, &RemarkEngine::isFailedOptRemarkEnabled);
+}
+
+InFlightRemark
+RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
+                                             StringRef category) {
+  return emitIfEnabled<OptRemarkAnalysis>(
+      loc, passName, category, &RemarkEngine::isAnalysisOptRemarkEnabled);
+}
+
+//===----------------------------------------------------------------------===//
+// RemarkStreamer
+//===----------------------------------------------------------------------===//
+void MLIRRemarkStreamer::streamOptimizationRemark(const RemarkBase &remark) {
+  if (!remarkStreamer.matchesFilter(remark.getPassName()))
+    return;
+
+  // First, convert the diagnostic to a remark.
+  llvm::remarks::Remark r = remark.generateRemark();
+  // Then, emit the remark through the serializer.
+  remarkStreamer.getSerializer().emit(r);
+}
+//===----------------------------------------------------------------------===//
+// Remarkengine
+//===----------------------------------------------------------------------===//
+
+void RemarkEngine::report(const RemarkBase &&diag) {
+  // Stream the remark
+  if (getLLVMRemarkStreamer() && remarksFile)
+    getLLVMRemarkStreamer()->streamOptimizationRemark(diag);
+
+  // Print using MLIR's diagnostic
+  if (printAsEmitRemarks) {
+    emitRemark(diag.getLocation(), diag.getMsg());
+  }
+}
+
+RemarkEngine::~RemarkEngine() {
+  if (remarksFile) {
+    remarksFile->keep();
+    remarksFile.reset();
+  }
+  setMainRemarkStreamer(nullptr);
+  setLLVMRemarkStreamer(nullptr);
+}
+
+llvm::Error RemarkEngine::initialize(StringRef outputPath,
+                                     StringRef outputFormat) {
+  if (remarksFile) {
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        "RemarkEngine is already initialized with an output file");
+  }
+
+  auto fFormatOrErr = llvm::remarks::parseFormat(outputFormat);
+  if (!fFormatOrErr) {
+    return fFormatOrErr.takeError();
+  }
+  llvm::remarks::Format fFormat = *fFormatOrErr;
+  std::error_code errCode;
+  llvm::sys::fs::OpenFlags fFlags = (fFormat == llvm::remarks::Format::YAML)
+                                        ? llvm::sys::fs::OF_Text
+                                        : llvm::sys::fs::OF_None;
+
+  remarksFile =
+      std::make_unique<llvm::ToolOutputFile>(outputPath, errCode, fFlags);
+  if (errCode) {
+    remarksFile.reset(); // force an empty optional
+    return llvm::createStringError(errCode, "Failed to open remarks file");
+  }
+
+  auto remarkSerializer = llvm::remarks::createRemarkSerializer(
+      *fFormatOrErr, llvm::remarks::SerializerMode::Separate,
+      remarksFile->os());
+  if (llvm::Error err = remarkSerializer.takeError()) {
+    return err;
+  }
+
+  // Create the main remark streamer.
+  setMainRemarkStreamer(std::make_unique<llvm::remarks::RemarkStreamer>(
+      std::move(*remarkSerializer), outputFormat));
+
+  setLLVMRemarkStreamer(
+      std::make_unique<MLIRRemarkStreamer>(*getMainRemarkStreamer()));
+
+  return llvm::ErrorSuccess();
+}
+
+RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
+                           std::optional<std::string> categoryPassName,
+                           std::optional<std::string> categoryMissName,
+                           std::optional<std::string> categoryAnalysisName,
+                           std::optional<std::string> categoryFailedName)
+    : printAsEmitRemarks(printAsEmitRemarks) {
+  if (categoryPassName)
+    passFilter = llvm::Regex(categoryPassName.value());
+  if (categoryMissName)
+    missFilter = llvm::Regex(categoryMissName.value());
+  if (categoryAnalysisName)
+    analysisFilter = llvm::Regex(categoryAnalysisName.value());
+  if (categoryFailedName)
+    failedFilter = llvm::Regex(categoryFailedName.value());
+}
diff --git a/mlir/unittests/IR/CMakeLists.txt b/mlir/unittests/IR/CMakeLists.txt
index a46e64718dab9..07b242f7440bb 100644
--- a/mlir/unittests/IR/CMakeLists.txt
+++ b/mlir/unittests/IR/CMakeLists.txt
@@ -14,6 +14,7 @@ add_mlir_unittest(MLIRIRTests
   MemrefLayoutTest.cpp
   OperationSupportTest.cpp
   PatternMatchTest.cpp
+  RemarkTest.cpp
   ShapedTypeTest.cpp
   SymbolTableTest.cpp
   TypeTest.cpp
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
new file mode 100644
index 0000000000000..8abddb44fd428
--- /dev/null
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -0,0 +1,106 @@
+//===- RemarkTest.cpp - Remark unit tests -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/Remarks.h"
+#include "mlir/Support/TypeID.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/YAMLParser.h"
+#include "gtest/gtest.h"
+#include <optional>
+
+using namespace llvm;
+using namespace mlir;
+using namespace mlir::detail;
+
+namespace {
+
+TEST(Remark, TestOutputOptimizationRemark) {
+  const auto *pass1Msg = "My message";
+  const auto *pass2Msg = "My another message";
+  const auto *pass3Msg = "Do not show this message";
+
+  auto *context = new MLIRContext();
+
+  std::string categoryLoopunroll("LoopUnroll");
+  std::string categoryInline("Inliner");
+  std::string myPassname1("myPass1");
+  std::string myPassname2("myPass2");
+  std::string funcName("myFunc");
+  std::string yamlFile = "/tmp/remarks.yaml";
+
+  Location loc = UnknownLoc::get(context);
+
+  // Setup the remark engine
+  context->setupOptimizationRemarks(yamlFile, "yaml", true, categoryLoopunroll,
+                                    std::nullopt, std::nullopt,
+                                    categoryLoopunroll);
+
+  // Remark 1: pass, category LoopUnroll
+  reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+  // Remark 2: failure, category LoopUnroll
+  reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
+  // Remark 3: pass, category Inline (should not be printed)
+  reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+
+  delete context;
+
+  // Read the file
+  auto bufferOrErr = MemoryBuffer::getFile(yamlFile);
+  ASSERT_TRUE(static_cast<bool>(bufferOrErr)) << "Failed to open remarks file";
+  std::string content = bufferOrErr.get()->getBuffer().str();
+
+  // Remark 1: pass, should be printed
+  EXPECT_NE(content.find("--- !Passed"), std::string::npos);
+  EXPECT_NE(content.find("Pass:            " + categoryLoopunroll),
+            std::string::npos);
+  EXPECT_NE(content.find("Name:            " + myPassname1), std::string::npos);
+  EXPECT_NE(content.find("String:          " + std::string(pass1Msg)),
+            std::string::npos);
+
+  // Remark 2: failure, should be printed
+  EXPECT_NE(content.find("--- !Failure"), std::string::npos);
+  EXPECT_NE(content.find("Name:            " + myPassname2), std::string::npos);
+  EXPECT_NE(content.find("String:          " + std::string(pass2Msg)),
+            std::string::npos);
+
+  // Remark 3: pass, category Inline (should not be printed)
+  EXPECT_EQ(content.find("String:          " + std::string(pass3Msg)),
+            std::string::npos);
+}
+
+TEST(Remark, TestNoOutputOptimizationRemark) {
+  const auto *pass1Msg = "My message";
+
+  auto *context = new MLIRContext();
+
+  std::string categoryFailName("myImportantCategory");
+  std::string myPassname1("myPass1");
+  std::string funcName("myFunc");
+  std::string yamlFile = "/tmp/remarks.yaml";
+
+  std::error_code ec =
+      llvm::sys::fs::remove(yamlFile, /*IgnoreNonExisting=*/true);
+  if (ec) {
+    FAIL() << "Failed to remove file " << yamlFile << ": " << ec.message();
+  }
+
+  Location loc = UnknownLoc::get(context);
+  reportOptimizationFail(loc, categoryFailName, myPassname1) << pass1Msg;
+
+  delete context;
+
+  // No setup, so no output file should be created
+  // check!
+  bool fileExists = llvm::sys::fs::exists(yamlFile);
+  EXPECT_FALSE(fileExists)
+      << "Expected no YAML file to be created without setupOptimizationRemarks";
+}
+
+} // namespace

>From 0aae05128946d52e5f5dd88fed5baaca8b510088 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 7 Aug 2025 11:19:47 +0000
Subject: [PATCH 2/2] address copilot

---
 mlir/include/mlir/IR/Remarks.h   |  1 -
 mlir/lib/IR/Remarks.cpp          | 16 +++++++---------
 mlir/unittests/IR/RemarkTest.cpp | 17 ++++++++++++-----
 3 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 8f7e7a900e7f1..240857b388587 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -82,7 +82,6 @@ class RemarkBase : public llvm::DiagnosticInfo {
 
   virtual bool isEnabled() const = 0;
   Location getLocation() const { return loc; }
-  llvm::remarks::RemarkLocation getRemarkLocation() const;
   /// Diagnostic -> Remark
   llvm::remarks::Remark generateRemark() const;
 
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 4d2aa95236f68..c0bae3915f0e0 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -103,21 +103,19 @@ llvm::remarks::Type RemarkBase::getRemarkType() const {
   llvm_unreachable("Unknown remark kind");
 }
 
-llvm::remarks::RemarkLocation RemarkBase::getRemarkLocation() const {
-  if (auto flc = dyn_cast<FileLineColLoc>(getLocation())) {
-    auto *buf = new std::string("./" + flc.getFilename().str());
-    return {*buf, flc.getLine(), flc.getColumn()};
-  }
-  return {"<unknown file>", 0, 0};
-}
-
 llvm::remarks::Remark RemarkBase::generateRemark() const {
+  auto locLambda = [&]() -> llvm::remarks::RemarkLocation {
+    if (auto flc = dyn_cast<FileLineColLoc>(getLocation()))
+      return {flc.getFilename(), flc.getLine(), flc.getColumn()};
+    return {"<unknown file>", 0, 0};
+  };
+
   llvm::remarks::Remark r; // The result.
   r.RemarkType = getRemarkType();
   r.PassName = getPassName();
   r.RemarkName = getRemarkName();
   r.FunctionName = getFunction();
-  r.Loc = getRemarkLocation();
+  r.Loc = locLambda();
   for (const RemarkBase::RemarkKeyValue &arg : getArgs()) {
     r.Args.emplace_back();
     r.Args.back().Key = arg.key;
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 8abddb44fd428..91bb6d82a6920 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -33,8 +33,12 @@ TEST(Remark, TestOutputOptimizationRemark) {
   std::string myPassname1("myPass1");
   std::string myPassname2("myPass2");
   std::string funcName("myFunc");
-  std::string yamlFile = "/tmp/remarks.yaml";
-
+  SmallString<64> tmpPathStorage;
+  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
+                            /*MakeAbsolute=*/true);
+  std::string yamlFile =
+      std::string(tmpPathStorage.data(), tmpPathStorage.size());
+  ASSERT_FALSE(yamlFile.empty());
   Location loc = UnknownLoc::get(context);
 
   // Setup the remark engine
@@ -77,14 +81,17 @@ TEST(Remark, TestOutputOptimizationRemark) {
 
 TEST(Remark, TestNoOutputOptimizationRemark) {
   const auto *pass1Msg = "My message";
-
   auto *context = new MLIRContext();
 
   std::string categoryFailName("myImportantCategory");
   std::string myPassname1("myPass1");
   std::string funcName("myFunc");
-  std::string yamlFile = "/tmp/remarks.yaml";
-
+  SmallString<64> tmpPathStorage;
+  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
+                            /*MakeAbsolute=*/true);
+  std::string yamlFile =
+      std::string(tmpPathStorage.data(), tmpPathStorage.size());
+  ASSERT_FALSE(yamlFile.empty());
   std::error_code ec =
       llvm::sys::fs::remove(yamlFile, /*IgnoreNonExisting=*/true);
   if (ec) {



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