[llvm-ir2vec] MIR2Vec support

Author: svkeerthy

llvm/docs/CommandGuide/llvm-ir2vec.rst

@@ -1,5 +1,5 @@
-llvm-ir2vec - IR2Vec Embedding Generation Tool
-==============================================
+llvm-ir2vec - IR2Vec and MIR2Vec Embedding Generation Tool
+===========================================================
 
 .. program:: llvm-ir2vec
 
@@ -11,9 +11,9 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
-:program:`llvm-ir2vec` is a standalone command-line tool for IR2Vec. It
-generates IR2Vec embeddings for LLVM IR and supports triplet generation 
-for vocabulary training. 
+:program:`llvm-ir2vec` is a standalone command-line tool for IR2Vec and MIR2Vec.
+It generates embeddings for both LLVM IR and Machine IR (MIR) and supports 
+triplet generation for vocabulary training. 
 
 The tool provides three main subcommands:
 
@@ -23,23 +23,33 @@ The tool provides three main subcommands:
 2. **entities**: Generates entity mapping files (entity2id.txt) for vocabulary 
    training.
 
-3. **embeddings**: Generates IR2Vec embeddings using a trained vocabulary
+3. **embeddings**: Generates IR2Vec or MIR2Vec embeddings using a trained vocabulary
    at different granularity levels (instruction, basic block, or function).
 
+The tool supports two operation modes:
+
+* **LLVM IR mode** (``--mode=llvm``): Process LLVM IR bitcode files and generate
+  IR2Vec embeddings
+* **Machine IR mode** (``--mode=mir``): Process Machine IR (.mir) files and generate
+  MIR2Vec embeddings
+
 The tool is designed to facilitate machine learning applications that work with
-LLVM IR by converting the IR into numerical representations that can be used by
-ML models. The `triplets` subcommand generates numeric IDs directly instead of string 
-triplets, streamlining the training data preparation workflow.
+LLVM IR or Machine IR by converting them into numerical representations that can 
+be used by ML models. The `triplets` subcommand generates numeric IDs directly 
+instead of string triplets, streamlining the training data preparation workflow.
 
 .. note::
 
-   For information about using IR2Vec programmatically within LLVM passes and 
-   the C++ API, see the `IR2Vec Embeddings <https://llvm.org/docs/MLGO.html#ir2vec-embeddings>`_ 
+   For information about using IR2Vec and MIR2Vec programmatically within LLVM 
+   passes and the C++ API, see the `IR2Vec Embeddings <https://llvm.org/docs/MLGO.html#ir2vec-embeddings>`_ 
    section in the MLGO documentation.
 
 OPERATION MODES
 ---------------
 
+The tool operates in two modes: **LLVM IR mode** and **Machine IR mode**. The mode
+is selected using the ``--mode`` option (default: ``llvm``).
+
 Triplet Generation and Entity Mapping Modes are used for preparing
 vocabulary and training data for knowledge graph embeddings. The Embedding Mode
 is used for generating embeddings from LLVM IR using a pre-trained vocabulary.
@@ -89,18 +99,31 @@ Embedding Generation
 ~~~~~~~~~~~~~~~~~~~~
 
 With the `embeddings` subcommand, :program:`llvm-ir2vec` uses a pre-trained vocabulary to
-generate numerical embeddings for LLVM IR at different levels of granularity.
+generate numerical embeddings for LLVM IR or Machine IR at different levels of granularity.
+
+Example Usage for LLVM IR:
+
+.. code-block:: bash
+
+   llvm-ir2vec embeddings --mode=llvm --ir2vec-vocab-path=vocab.json --ir2vec-kind=symbolic --level=func input.bc -o embeddings.txt
 
-Example Usage:
+Example Usage for Machine IR:
 
 .. code-block:: bash
 
-   llvm-ir2vec embeddings --ir2vec-vocab-path=vocab.json --ir2vec-kind=symbolic --level=func input.bc -o embeddings.txt
+   llvm-ir2vec embeddings --mode=mir --mir2vec-vocab-path=vocab.json --level=func input.mir -o embeddings.txt
 
 OPTIONS
 -------
 
-Global options:
+Common options (applicable to both LLVM IR and Machine IR modes):
+
+.. option:: --mode=<mode>
+
+   Specify the operation mode. Valid values are:
+
+   * ``llvm`` - Process LLVM IR bitcode files (default)
+   * ``mir`` - Process Machine IR (.mir) files
 
 .. option:: -o <filename>
 
@@ -116,8 +139,8 @@ Subcommand-specific options:
 
 .. option:: <input-file>
 
-   The input LLVM IR or bitcode file to process. This positional argument is
-   required for the `embeddings` subcommand.
+   The input LLVM IR/bitcode file (.ll/.bc) or Machine IR file (.mir) to process. 
+   This positional argument is required for the `embeddings` subcommand.
 
 .. option:: --level=<level>
 
@@ -131,6 +154,8 @@ Subcommand-specific options:
 
    Process only the specified function instead of all functions in the module.
 
+**IR2Vec-specific options** (for ``--mode=llvm``):
+
 .. option:: --ir2vec-kind=<kind>
 
    Specify the kind of IR2Vec embeddings to generate. Valid values are:
@@ -143,8 +168,8 @@ Subcommand-specific options:
 
 .. option:: --ir2vec-vocab-path=<path>
 
-   Specify the path to the vocabulary file (required for embedding generation).
-   The vocabulary file should be in JSON format and contain the trained
+   Specify the path to the IR2Vec vocabulary file (required for LLVM IR embedding 
+   generation). The vocabulary file should be in JSON format and contain the trained
    vocabulary for embedding generation. See `llvm/lib/Analysis/models`
    for pre-trained vocabulary files.
 
@@ -163,6 +188,35 @@ Subcommand-specific options:
    Specify the weight for argument embeddings (default: 0.2). This controls
    the relative importance of operand information in the final embedding.
 
+**MIR2Vec-specific options** (for ``--mode=mir``):
+
+.. option:: --mir2vec-vocab-path=<path>
+
+   Specify the path to the MIR2Vec vocabulary file (required for Machine IR 
+   embedding generation). The vocabulary file should be in JSON format and 
+   contain the trained vocabulary for embedding generation.
+
+.. option:: --mir2vec-kind=<kind>
+
+   Specify the kind of MIR2Vec embeddings to generate. Valid values are:
+
+   * ``symbolic`` - Generate symbolic embeddings (default)
+
+.. option:: --mir2vec-opc-weight=<weight>
+
+   Specify the weight for machine opcode embeddings (default: 1.0). This controls
+   the relative importance of machine instruction opcodes in the final embedding.
+
+.. option:: --mir2vec-common-operand-weight=<weight>
+
+   Specify the weight for common operand embeddings (default: 1.0). This controls
+   the relative importance of common operand types in the final embedding.
+
+.. option:: --mir2vec-reg-operand-weight=<weight>
+
+   Specify the weight for register operand embeddings (default: 1.0). This controls
+   the relative importance of register operands in the final embedding.
+
 
 **triplets** subcommand:
 
@@ -240,3 +294,6 @@ SEE ALSO
 
 For more information about the IR2Vec algorithm and approach, see:
 `IR2Vec: LLVM IR Based Scalable Program Embeddings <https://doi.org/10.1145/3418463>`_.
+
+For more information about the MIR2Vec algorithm and approach, see:
+`RL4ReAl: Reinforcement Learning for Register Allocation <https://doi.org/10.1145/3578360.3580273>`_.

llvm/include/llvm/CodeGen/MIR2Vec.h

@@ -7,9 +7,20 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// This file defines the MIR2Vec vocabulary
-/// analysis(MIR2VecVocabLegacyAnalysis), the core mir2vec::MIREmbedder
-/// interface for generating Machine IR embeddings, and related utilities.
+/// This file defines the MIR2Vec framework for generating Machine IR
+/// embeddings.
+///
+/// Architecture Overview:
+/// ----------------------
+/// 1. MIR2VecVocabProvider - Core vocabulary loading logic (no PM dependency)
+///    - Can be used standalone or wrapped by the pass manager
+///    - Requires MachineModuleInfo with parsed machine functions
+///
+/// 2. MIR2VecVocabLegacyAnalysis - Pass manager wrapper (ImmutablePass)
+///    - Integrated and used by llc -print-mir2vec
+///
+/// 3. MIREmbedder - Generates embeddings from vocabulary
+///    - SymbolicMIREmbedder: MIR2Vec embedding implementation
 ///
 /// MIR2Vec extends IR2Vec to support Machine IR embeddings. It represents the
 /// LLVM Machine IR as embeddings which can be used as input to machine learning
@@ -306,26 +317,58 @@ class SymbolicMIREmbedder : public MIREmbedder {
 
 } // namespace mir2vec
 
+/// MIR2Vec vocabulary provider used by pass managers and standalone tools.
+/// This class encapsulates the core vocabulary loading logic and can be used
+/// independently of the pass manager infrastructure. For pass-based usage,
+/// see MIR2VecVocabLegacyAnalysis.
+///
+/// Note: This provider pattern makes new PM migration straightforward when
+/// needed. A new PM analysis wrapper can be added that delegates to this
+/// provider, similar to how MIR2VecVocabLegacyAnalysis currently wraps it.
+class MIR2VecVocabProvider {
+  using VocabMap = std::map<std::string, mir2vec::Embedding>;
+
+public:
+  MIR2VecVocabProvider(const MachineModuleInfo &MMI) : MMI(MMI) {}
+
+  Expected<mir2vec::MIRVocabulary> getVocabulary(const Module &M);
+
+private:
+  Error readVocabulary(VocabMap &OpcVocab, VocabMap &CommonOperandVocab,
+                       VocabMap &PhyRegVocabMap, VocabMap &VirtRegVocabMap);
+  const MachineModuleInfo &MMI;
+};
+
 /// Pass to analyze and populate MIR2Vec vocabulary from a module
 class MIR2VecVocabLegacyAnalysis : public ImmutablePass {
   using VocabVector = std::vector<mir2vec::Embedding>;
   using VocabMap = std::map<std::string, mir2vec::Embedding>;
-  std::optional<mir2vec::MIRVocabulary> Vocab;
 
   StringRef getPassName() const override;
-  Error readVocabulary(VocabMap &OpcVocab, VocabMap &CommonOperandVocab,
-                       VocabMap &PhyRegVocabMap, VocabMap &VirtRegVocabMap);
 
 protected:
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<MachineModuleInfoWrapperPass>();
     AU.setPreservesAll();
   }
+  std::unique_ptr<MIR2VecVocabProvider> Provider;
 
 public:
   static char ID;
   MIR2VecVocabLegacyAnalysis() : ImmutablePass(ID) {}
-  Expected<mir2vec::MIRVocabulary> getMIR2VecVocabulary(const Module &M);
+
+  Expected<mir2vec::MIRVocabulary> getMIR2VecVocabulary(const Module &M) {
+    MachineModuleInfo &MMI =
+        getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
+    if (!Provider)
+      Provider = std::make_unique<MIR2VecVocabProvider>(MMI);
+    return Provider->getVocabulary(M);
+  }
+
+  MIR2VecVocabProvider &getProvider() {
+    assert(Provider && "Provider not initialized");
+    return *Provider;
+  }
 };
 
 /// This pass prints the embeddings in the MIR2Vec vocabulary

llvm/lib/CodeGen/MIR2Vec.cpp

@@ -417,24 +417,39 @@ Expected<MIRVocabulary> MIRVocabulary::createDummyVocabForTest(
 }
 
 //===----------------------------------------------------------------------===//
-// MIR2VecVocabLegacyAnalysis Implementation
+// MIR2VecVocabProvider and MIR2VecVocabLegacyAnalysis
 //===----------------------------------------------------------------------===//
 
-char MIR2VecVocabLegacyAnalysis::ID = 0;
-INITIALIZE_PASS_BEGIN(MIR2VecVocabLegacyAnalysis, "mir2vec-vocab-analysis",
-                      "MIR2Vec Vocabulary Analysis", false, true)
-INITIALIZE_PASS_DEPENDENCY(MachineModuleInfoWrapperPass)
-INITIALIZE_PASS_END(MIR2VecVocabLegacyAnalysis, "mir2vec-vocab-analysis",
-                    "MIR2Vec Vocabulary Analysis", false, true)
+Expected<mir2vec::MIRVocabulary>
+MIR2VecVocabProvider::getVocabulary(const Module &M) {
+  VocabMap OpcVocab, CommonOperandVocab, PhyRegVocabMap, VirtRegVocabMap;
 
-StringRef MIR2VecVocabLegacyAnalysis::getPassName() const {
-  return "MIR2Vec Vocabulary Analysis";
+  if (Error Err = readVocabulary(OpcVocab, CommonOperandVocab, PhyRegVocabMap,
+                                 VirtRegVocabMap))
+    return std::move(Err);
+
+  for (const auto &F : M) {
+    if (F.isDeclaration())
+      continue;
+
+    if (auto *MF = MMI.getMachineFunction(F)) {
+      auto &Subtarget = MF->getSubtarget();
+      if (const auto *TII = Subtarget.getInstrInfo())
+        if (const auto *TRI = Subtarget.getRegisterInfo())
+          return mir2vec::MIRVocabulary::create(
+              std::move(OpcVocab), std::move(CommonOperandVocab),
+              std::move(PhyRegVocabMap), std::move(VirtRegVocabMap), *TII, *TRI,
+              MF->getRegInfo());
+    }
+  }
+  return createStringError(errc::invalid_argument,
+                           "No machine functions found in module");
 }
 
-Error MIR2VecVocabLegacyAnalysis::readVocabulary(VocabMap &OpcodeVocab,
-                                                 VocabMap &CommonOperandVocab,
-                                                 VocabMap &PhyRegVocabMap,
-                                                 VocabMap &VirtRegVocabMap) {
+Error MIR2VecVocabProvider::readVocabulary(VocabMap &OpcodeVocab,
+                                           VocabMap &CommonOperandVocab,
+                                           VocabMap &PhyRegVocabMap,
+                                           VocabMap &VirtRegVocabMap) {
   if (VocabFile.empty())
     return createStringError(
         errc::invalid_argument,
@@ -483,49 +498,15 @@ Error MIR2VecVocabLegacyAnalysis::readVocabulary(VocabMap &OpcodeVocab,
   return Error::success();
 }
 
-Expected<mir2vec::MIRVocabulary>
-MIR2VecVocabLegacyAnalysis::getMIR2VecVocabulary(const Module &M) {
-  if (Vocab.has_value())
-    return std::move(Vocab.value());
-
-  VocabMap OpcMap, CommonOperandMap, PhyRegMap, VirtRegMap;
-  if (Error Err =
-          readVocabulary(OpcMap, CommonOperandMap, PhyRegMap, VirtRegMap))
-    return std::move(Err);
-
-  // Get machine module info to access machine functions and target info
-  MachineModuleInfo &MMI = getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
-
-  // Find first available machine function to get target instruction info
-  for (const auto &F : M) {
-    if (F.isDeclaration())
-      continue;
-
-    if (auto *MF = MMI.getMachineFunction(F)) {
-      auto &Subtarget = MF->getSubtarget();
-      const TargetInstrInfo *TII = Subtarget.getInstrInfo();
-      if (!TII) {
-        return createStringError(errc::invalid_argument,
-                                 "No TargetInstrInfo available; cannot create "
-                                 "MIR2Vec vocabulary");
-      }
-
-      const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
-      if (!TRI) {
-        return createStringError(errc::invalid_argument,
-                                 "No TargetRegisterInfo available; cannot "
-                                 "create MIR2Vec vocabulary");
-      }
-
-      return mir2vec::MIRVocabulary::create(
-          std::move(OpcMap), std::move(CommonOperandMap), std::move(PhyRegMap),
-          std::move(VirtRegMap), *TII, *TRI, MF->getRegInfo());
-    }
-  }
+char MIR2VecVocabLegacyAnalysis::ID = 0;
+INITIALIZE_PASS_BEGIN(MIR2VecVocabLegacyAnalysis, "mir2vec-vocab-analysis",
+                      "MIR2Vec Vocabulary Analysis", false, true)
+INITIALIZE_PASS_DEPENDENCY(MachineModuleInfoWrapperPass)
+INITIALIZE_PASS_END(MIR2VecVocabLegacyAnalysis, "mir2vec-vocab-analysis",
+                    "MIR2Vec Vocabulary Analysis", false, true)
 
-  // No machine functions available - return error
-  return createStringError(errc::invalid_argument,
-                           "No machine functions found in module");
+StringRef MIR2VecVocabLegacyAnalysis::getPassName() const {
+  return "MIR2Vec Vocabulary Analysis";
 }
 
 //===----------------------------------------------------------------------===//