Handle Operands

Author: svkeerthy

llvm/include/llvm/CodeGen/MIR2Vec.h

@@ -35,6 +35,8 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
@@ -61,7 +63,7 @@ class MIREmbedder;
 class SymbolicMIREmbedder;
 
 extern llvm::cl::OptionCategory MIR2VecCategory;
-extern cl::opt<float> OpcWeight;
+extern cl::opt<float> OpcWeight, CommonOperandWeight, RegOperandWeight;
 
 using Embedding = ir2vec::Embedding;
 using MachineInstEmbeddingsMap = DenseMap<const MachineInstr *, Embedding>;
@@ -74,31 +76,114 @@ class MIRVocabulary {
   friend class llvm::MIR2VecVocabLegacyAnalysis;
   using VocabMap = std::map<std::string, ir2vec::Embedding>;
 
-private:
-  // Define vocabulary layout - adapted for MIR
+  // MIRVocabulary Layout:
+  // +-------------------+-----------------------------------------------------+
+  // | Entity Type       | Description                                         |
+  // +-------------------+-----------------------------------------------------+
+  // | 1. Opcodes        | Target specific opcodes derived from TII, grouped   |
+  // |                   | by instruction semantics.                           |
+  // | 2. Common Operands| All common operand types, except register operands, |
+  // |                   | defined by MachineOperand::MachineOperandType enum. |
+  // | 3. Physical       | Register classes defined by the target, specialized |
+  // |    Reg classes    | by physical registers.                              |
+  // | 4. Virtual        | Register classes defined by the target, specialized |
+  // |    Reg classes    | by virtual and physical registers.                  |
+  // +-------------------+-----------------------------------------------------+
+
+  /// Layout information for the MIR vocabulary. Defines the starting index
+  /// and size of each section in the vocabulary.
   struct {
     size_t OpcodeBase = 0;
-    size_t OperandBase = 0;
+    size_t CommonOperandBase = 0;
+    size_t PhyRegBase = 0;
+    size_t VirtRegBase = 0;
     size_t TotalEntries = 0;
   } Layout;
 
-  enum class Section : unsigned { Opcodes = 0, MaxSections };
+  enum class Section : unsigned {
+    Opcodes = 0,
+    CommonOperands = 1,
+    PhyRegisters = 2,
+    VirtRegisters = 3,
+    MaxSections
+  };
 
   ir2vec::VocabStorage Storage;
   mutable std::set<std::string> UniqueBaseOpcodeNames;
+  mutable SmallVector<std::string, 24> RegisterOperandNames;
+
+  // Some instructions have optional register operands that may be NoRegister.
+  // We return a zero vector in such cases.
+  mutable Embedding ZeroEmbedding;
+
+  // We have specialized MO_Register handling in the Register operand section,
+  // so we don't include it here. Also, no MO_DbgInstrRef for now.
+  static constexpr StringLiteral CommonOperandNames[] = {
+      "Immediate",       "CImmediate",        "FPImmediate",  "MBB",
+      "FrameIndex",      "ConstantPoolIndex", "TargetIndex",  "JumpTableIndex",
+      "ExternalSymbol",  "GlobalAddress",     "BlockAddress", "RegisterMask",
+      "RegisterLiveOut", "Metadata",          "MCSymbol",     "CFIIndex",
+      "IntrinsicID",     "Predicate",         "ShuffleMask"};
+  static_assert(std::size(CommonOperandNames) == MachineOperand::MO_Last - 1 &&
+                "Common operand names size changed, update accordingly");
+
   const TargetInstrInfo &TII;
-  void generateStorage(const VocabMap &OpcodeMap);
+  const TargetRegisterInfo &TRI;
+  const MachineRegisterInfo &MRI;
+
+  void generateStorage(const VocabMap &OpcodeMap,
+                       const VocabMap &CommonOperandMap,
+                       const VocabMap &PhyRegMap, const VocabMap &VirtRegMap);
   void buildCanonicalOpcodeMapping();
+  void buildRegisterOperandMapping();
 
   /// Get canonical index for a machine opcode
   unsigned getCanonicalOpcodeIndex(unsigned Opcode) const;
 
+  /// Get index for a common (non-register) machine operand
+  unsigned
+  getCommonOperandIndex(MachineOperand::MachineOperandType OperandType) const;
+
+  /// Get index for a register machine operand
+  unsigned getRegisterOperandIndex(Register Reg) const;
+
+  // Accessors for operand types
+  const Embedding &
+  operator[](MachineOperand::MachineOperandType OperandType) const {
+    unsigned LocalIndex = getCommonOperandIndex(OperandType);
+    return Storage[static_cast<unsigned>(Section::CommonOperands)][LocalIndex];
+  }
+
+  const Embedding &operator[](Register Reg) const {
+    // Reg is sometimes NoRegister (0) for optional operands. We return a zero
+    // vector in this case.
+    if (!Reg.isValid())
+      return ZeroEmbedding;
+    // TODO: Implement proper stack slot handling for MIR2Vec embeddings.
+    // Stack slots represent frame indices and should have their own
+    // embedding strategy rather than defaulting to register class 0.
+    // Consider: 1) Separate vocabulary section for stack slots
+    //          2) Stack slot size/alignment based embeddings
+    //          3) Frame index based categorization
+    if (Reg.isStack())
+      return ZeroEmbedding;
+
+    unsigned LocalIndex = getRegisterOperandIndex(Reg);
+    auto SectionID =
+        Reg.isPhysical() ? Section::PhyRegisters : Section::VirtRegisters;
+    return Storage[static_cast<unsigned>(SectionID)][LocalIndex];
+  }
+
 public:
   /// Static method for extracting base opcode names (public for testing)
   static std::string extractBaseOpcodeName(StringRef InstrName);
 
-  /// Get canonical index for base name (public for testing)
+  /// Get indices from opcode or operand names. These are public for testing.
+  /// String based lookups are inefficient and should be avoided in general.
   unsigned getCanonicalIndexForBaseName(StringRef BaseName) const;
+  unsigned getCanonicalIndexForOperandName(StringRef OperandName) const;
+  unsigned getCanonicalIndexForRegisterClass(StringRef RegName,
+                                             bool IsPhysical = true) const;
 
   /// Get the string key for a vocabulary entry at the given position
   std::string getStringKey(unsigned Pos) const;
@@ -111,6 +196,14 @@ class MIRVocabulary {
     return Storage[static_cast<unsigned>(Section::Opcodes)][LocalIndex];
   }
 
+  const Embedding &operator[](MachineOperand Operand) const {
+    auto OperandType = Operand.getType();
+    if (OperandType == MachineOperand::MO_Register)
+      return operator[](Operand.getReg());
+    else
+      return operator[](OperandType);
+  }
+
   // Iterator access
   using const_iterator = ir2vec::VocabStorage::const_iterator;
   const_iterator begin() const { return Storage.begin(); }
@@ -120,18 +213,25 @@ class MIRVocabulary {
   MIRVocabulary() = delete;
 
   /// Factory method to create MIRVocabulary from vocabulary map
-  static Expected<MIRVocabulary> create(VocabMap &&Entries,
-                                        const TargetInstrInfo &TII);
+  static Expected<MIRVocabulary>
+  create(VocabMap &&OpcMap, VocabMap &&CommonOperandsMap, VocabMap &&PhyRegMap,
+         VocabMap &&VirtRegMap, const TargetInstrInfo &TII,
+         const TargetRegisterInfo &TRI, const MachineRegisterInfo &MRI);
 
   /// Create a dummy vocabulary for testing purposes.
   static Expected<MIRVocabulary>
-  createDummyVocabForTest(const TargetInstrInfo &TII, unsigned Dim = 1);
+  createDummyVocabForTest(const TargetInstrInfo &TII,
+                          const TargetRegisterInfo &TRI,
+                          const MachineRegisterInfo &MRI, unsigned Dim = 1);
 
   /// Total number of entries in the vocabulary
   size_t getCanonicalSize() const { return Storage.size(); }
 
 private:
-  MIRVocabulary(VocabMap &&Entries, const TargetInstrInfo &TII);
+  MIRVocabulary(VocabMap &&OpcMap, VocabMap &&CommonOperandsMap,
+                VocabMap &&PhyRegMap, VocabMap &&VirtRegMap,
+                const TargetInstrInfo &TII, const TargetRegisterInfo &TRI,
+                const MachineRegisterInfo &MRI);
 };
 
 /// Base class for MIR embedders
@@ -144,11 +244,13 @@ class MIREmbedder {
   const unsigned Dimension;
 
   /// Weight for opcode embeddings
-  const float OpcWeight;
+  const float OpcWeight, CommonOperandWeight, RegOperandWeight;
 
   MIREmbedder(const MachineFunction &MF, const MIRVocabulary &Vocab)
       : MF(MF), Vocab(Vocab), Dimension(Vocab.getDimension()),
-        OpcWeight(mir2vec::OpcWeight) {}
+        OpcWeight(mir2vec::OpcWeight),
+        CommonOperandWeight(mir2vec::CommonOperandWeight),
+        RegOperandWeight(mir2vec::RegOperandWeight) {}
 
   /// Function to compute embeddings.
   Embedding computeEmbeddings() const;
@@ -208,11 +310,11 @@ class SymbolicMIREmbedder : public MIREmbedder {
 class MIR2VecVocabLegacyAnalysis : public ImmutablePass {
   using VocabVector = std::vector<mir2vec::Embedding>;
   using VocabMap = std::map<std::string, mir2vec::Embedding>;
-  VocabMap StrVocabMap;
-  VocabVector Vocab;
+  std::optional<mir2vec::MIRVocabulary> Vocab;
 
   StringRef getPassName() const override;
-  Error readVocabulary();
+  Error readVocabulary(VocabMap &OpcVocab, VocabMap &CommonOperandVocab,
+                       VocabMap &PhyRegVocabMap, VocabMap &VirtRegVocabMap);
 
 protected:
   void getAnalysisUsage(AnalysisUsage &AU) const override {
@@ -275,4 +377,4 @@ MachineFunctionPass *createMIR2VecPrinterLegacyPass(raw_ostream &OS);
 
 } // namespace llvm
 
-#endif // LLVM_CODEGEN_MIR2VEC_H
+#endif // LLVM_CODEGEN_MIR2VEC_H