add TableGen support to create relationship maps between instructions

Relationship maps are represented as InstrMapping records which are parsed by
TableGen and the information is used to construct mapping tables to represent
appropriate relations between instructions. These tables are emitted into
XXXGenInstrInfo.inc file along with the functions to query them.

Patch by Jyotsna Verma <jverma@codeaurora.org>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166685 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 612 insertions, 0 deletions

diff --git a/utils/TableGen/CodeGenMapTable.cpp b/utils/TableGen/CodeGenMapTable.cpp
new file mode 100644
index 0000000000..c08c33c46a
--- /dev/null
+++ b/utils/TableGen/CodeGenMapTable.cpp
@@ -0,0 +1,609 @@
+//===- CodeGenMapTable.cpp - Instruction Mapping Table Generator ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// CodeGenMapTable provides functionality for the TabelGen to create
+// relation mapping between instructions. Relation models are defined using
+// InstrMapping as a base class. This file implements the functionality which
+// parses these definitions and generates relation maps using the information
+// specified there. These maps are emitted as tables in the XXXGenInstrInfo.inc
+// file along with the functions to query them.
+//
+// A relationship model to relate non-predicate instructions with their
+// predicated true/false forms can be defined as follows:
+//
+// def getPredOpcode : InstrMapping {
+//  let FilterClass = "PredRel";
+//  let RowFields = ["BaseOpcode"];
+//  let ColFields = ["PredSense"];
+//  let KeyCol = ["none"];
+//  let ValueCols = [["true"], ["false"]]; }
+//
+// CodeGenMapTable parses this map and generates a table in XXXGenInstrInfo.inc
+// file that contains the instructions modeling this relationship. This table
+// is defined in the function
+// "int getPredOpcode(uint16_t Opcode, enum PredSense inPredSense)"
+// that can be used to retrieve the predicated form of the instruction by
+// passing its opcode value and the predicate sense (true/false) of the desired
+// instruction as arguments.
+//
+// Short description of the algorithm:
+//
+// 1) Iterate through all the records that derive from "InstrMapping" class.
+// 2) For each record, filter out instructions based on the FilterClass value.
+// 3) Iterate through this set of instructions and insert them into
+// RowInstrMap map based on their RowFields values. RowInstrMap is keyed by the
+// vector of RowFields values and contains vectors of Records (instructions) as
+// values. RowFields is a list of fields that are required to have the same
+// values for all the instructions appearing in the same row of the relation
+// table. All the instructions in a given row of the relation table have some
+// sort of relationship with the key instruction defined by the corresponding
+// relationship model.
+//
+// Ex: RowInstrMap(RowVal1, RowVal2, ...) -> [Instr1, Instr2, Instr3, ... ]
+// Here Instr1, Instr2, Instr3 have same values (RowVal1, RowVal2) for
+// RowFields. These groups of instructions are later matched against ValueCols
+// to determine the column they belong to, if any.
+//
+// While building the RowInstrMap map, collect all the key instructions in
+// KeyInstrVec. These are the instructions having the same values as KeyCol
+// for all the fields listed in ColFields.
+//
+// For Example:
+//
+// Relate non-predicate instructions with their predicated true/false forms.
+//
+// def getPredOpcode : InstrMapping {
+//  let FilterClass = "PredRel";
+//  let RowFields = ["BaseOpcode"];
+//  let ColFields = ["PredSense"];
+//  let KeyCol = ["none"];
+//  let ValueCols = [["true"], ["false"]]; }
+//
+// Here, only instructions that have "none" as PredSense will be selected as key
+// instructions.
+//
+// 4) For each key instruction, get the group of instructions that share the
+// same key-value as the key instruction from RowInstrMap. Iterate over the list
+// of columns in ValueCols (it is defined as a list<list<string> >. Therefore,
+// it can specify multi-column relationships). For each column, find the
+// instruction from the group that matches all the values for the column.
+// Multiple matches are not allowed.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenTarget.h"
+#include "llvm/Support/Format.h"
+using namespace llvm;
+typedef std::map<std::string, std::vector<Record*> > InstrRelMapTy;
+
+typedef std::map<std::vector<Init*>, std::vector<Record*> > RowInstrMapTy;
+
+namespace {
+
+//===----------------------------------------------------------------------===//
+// This class is used to represent InstrMapping class defined in Target.td file.
+class InstrMap {
+private:
+  std::string Name;
+  std::string FilterClass;
+  ListInit *RowFields;
+  ListInit *ColFields;
+  ListInit *KeyCol;
+  std::vector<ListInit*> ValueCols;
+
+public:
+  InstrMap(Record* MapRec) {
+    Name = MapRec->getName();
+
+    // FilterClass - It's used to reduce the search space only to the
+    // instructions that define the kind of relationship modeled by
+    // this InstrMapping object/record.
+    const RecordVal *Filter = MapRec->getValue("FilterClass");
+    FilterClass = Filter->getValue()->getAsUnquotedString();
+
+    // List of fields/attributes that need to be same across all the
+    // instructions in a row of the relation table.
+    RowFields = MapRec->getValueAsListInit("RowFields");
+
+    // List of fields/attributes that are constant across all the instruction
+    // in a column of the relation table. Ex: ColFields = 'predSense'
+    ColFields = MapRec->getValueAsListInit("ColFields");
+
+    // Values for the fields/attributes listed in 'ColFields'.
+    // Ex: KeyCol = 'noPred' -- key instruction is non predicated
+    KeyCol = MapRec->getValueAsListInit("KeyCol");
+
+    // List of values for the fields/attributes listed in 'ColFields', one for
+    // each column in the relation table.
+    //
+    // Ex: ValueCols = [['true'],['false']] -- it results two columns in the
+    // table. First column requires all the instructions to have predSense
+    // set to 'true' and second column requires it to be 'false'.
+    ListInit *ColValList = MapRec->getValueAsListInit("ValueCols");
+
+    // Each instruction map must specify at least one column for it to be valid.
+    if (ColValList->getSize() == 0)
+      throw "InstrMapping record `" + MapRec->getName() + "' has empty " +
+            "`ValueCols' field!";
+
+    for (unsigned i = 0, e = ColValList->getSize(); i < e; i++) {
+      ListInit *ColI = dyn_cast<ListInit>(ColValList->getElement(i));
+
+      // Make sure that all the sub-lists in 'ValueCols' have same number of
+      // elements as the fields in 'ColFields'.
+      if (ColI->getSize() == ColFields->getSize())
+        ValueCols.push_back(ColI);
+      else {
+        throw "Record `" + MapRec->getName() + "', field `" + "ValueCols" +
+            "' entries don't match with the entries in 'ColFields'!";
+      }
+    }
+  }
+
+  std::string getName() const {
+    return Name;
+  }
+
+  std::string getFilterClass() {
+    return FilterClass;
+  }
+
+  ListInit *getRowFields() const {
+    return RowFields;
+  }
+
+  ListInit *getColFields() const {
+    return ColFields;
+  }
+
+  ListInit *getKeyCol() const {
+    return KeyCol;
+  }
+
+  const std::vector<ListInit*> &getValueCols() const {
+    return ValueCols;
+  }
+};
+} // End anonymous namespace.
+
+
+//===----------------------------------------------------------------------===//
+// class MapTableEmitter : It builds the instruction relation maps using
+// the information provided in InstrMapping records. It outputs these
+// relationship maps as tables into XXXGenInstrInfo.inc file along with the
+// functions to query them.
+
+namespace {
+class MapTableEmitter {
+private:
+//  std::string TargetName;
+  const CodeGenTarget &Target;
+  RecordKeeper &Records;
+  // InstrMapDesc - InstrMapping record to be processed.
+  InstrMap InstrMapDesc;
+
+  // InstrDefs - list of instructions filtered using FilterClass defined
+  // in InstrMapDesc.
+  std::vector<Record*> InstrDefs;
+
+  // RowInstrMap - maps RowFields values to the instructions. It's keyed by the
+  // values of the row fields and contains vector of records as values.
+  RowInstrMapTy RowInstrMap;
+
+  // KeyInstrVec - list of key instructions.
+  std::vector<Record*> KeyInstrVec;
+  DenseMap<Record*, std::vector<Record*> > MapTable;
+
+public:
+  MapTableEmitter(CodeGenTarget &Target, RecordKeeper &Records, Record *IMRec):
+                  Target(Target), Records(Records), InstrMapDesc(IMRec) {
+    const std::string FilterClass = InstrMapDesc.getFilterClass();
+    InstrDefs = Records.getAllDerivedDefinitions(FilterClass);
+  };
+
+  void buildRowInstrMap();
+
+  // Returns true if an instruction is a key instruction, i.e., its ColFields
+  // have same values as KeyCol.
+  bool isKeyColInstr(Record* CurInstr);
+
+  // Find column instruction corresponding to a key instruction based on the
+  // constraints for that column.
+  Record *getInstrForColumn(Record *KeyInstr, ListInit *CurValueCol);
+
+  // Find column instructions for each key instruction based
+  // on ValueCols and store them into MapTable.
+  void buildMapTable();
+
+  void emitBinSearch(raw_ostream &OS, unsigned TableSize);
+  void emitTablesWithFunc(raw_ostream &OS);
+  unsigned emitBinSearchTable(raw_ostream &OS);
+
+  // Lookup functions to query binary search tables.
+  void emitMapFuncBody(raw_ostream &OS, unsigned TableSize);
+
+};
+} // End anonymous namespace.
+
+
+//===----------------------------------------------------------------------===//
+// Process all the instructions that model this relation (alreday present in
+// InstrDefs) and insert them into RowInstrMap which is keyed by the values of
+// the fields listed as RowFields. It stores vectors of records as values.
+// All the related instructions have the same values for the RowFields thus are
+// part of the same key-value pair.
+//===----------------------------------------------------------------------===//
+
+void MapTableEmitter::buildRowInstrMap() {
+  for (unsigned i = 0, e = InstrDefs.size(); i < e; i++) {
+    std::vector<Record*> InstrList;
+    Record *CurInstr = InstrDefs[i];
+    std::vector<Init*> KeyValue;
+    ListInit *RowFields = InstrMapDesc.getRowFields();
+    for (unsigned j = 0, endRF = RowFields->getSize(); j < endRF; j++) {
+      Init *RowFieldsJ = RowFields->getElement(j);
+      Init *CurInstrVal = CurInstr->getValue(RowFieldsJ)->getValue();
+      KeyValue.push_back(CurInstrVal);
+    }
+
+    // Collect key instructions into KeyInstrVec. Later, these instructions are
+    // processed to assign column position to the instructions sharing
+    // their KeyValue in RowInstrMap.
+    if (isKeyColInstr(CurInstr))
+      KeyInstrVec.push_back(CurInstr);
+
+    RowInstrMap[KeyValue].push_back(CurInstr);
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Return true if an instruction is a KeyCol instruction.
+//===----------------------------------------------------------------------===//
+
+bool MapTableEmitter::isKeyColInstr(Record* CurInstr) {
+  ListInit *ColFields = InstrMapDesc.getColFields();
+  ListInit *KeyCol = InstrMapDesc.getKeyCol();
+
+  // Check if the instruction is a KeyCol instruction.
+  bool MatchFound = true;
+  for (unsigned j = 0, endCF = ColFields->getSize();
+      (j < endCF) && MatchFound; j++) {
+    RecordVal *ColFieldName = CurInstr->getValue(ColFields->getElement(j));
+    std::string CurInstrVal = ColFieldName->getValue()->getAsUnquotedString();
+    std::string KeyColValue = KeyCol->getElement(j)->getAsUnquotedString();
+    MatchFound = (CurInstrVal == KeyColValue);
+  }
+  return MatchFound;
+}
+
+//===----------------------------------------------------------------------===//
+// Build a map to link key instructions with the column instructions arranged
+// according to their column positions.
+//===----------------------------------------------------------------------===//
+
+void MapTableEmitter::buildMapTable() {
+  // Find column instructions for a given key based on the ColField
+  // constraints.
+  const std::vector<ListInit*> &ValueCols = InstrMapDesc.getValueCols();
+  unsigned NumOfCols = ValueCols.size();
+  for (unsigned j = 0, endKI = KeyInstrVec.size(); j < endKI; j++) {
+    Record *CurKeyInstr = KeyInstrVec[j];
+    std::vector<Record*> ColInstrVec(NumOfCols);
+
+    // Find the column instruction based on the constraints for the column.
+    for (unsigned ColIdx = 0; ColIdx < NumOfCols; ColIdx++) {
+      ListInit *CurValueCol = ValueCols[ColIdx];
+      Record *ColInstr = getInstrForColumn(CurKeyInstr, CurValueCol);
+      ColInstrVec[ColIdx] = ColInstr;
+    }
+    MapTable[CurKeyInstr] = ColInstrVec;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Find column instruction based on the constraints for that column.
+//===----------------------------------------------------------------------===//
+
+Record *MapTableEmitter::getInstrForColumn(Record *KeyInstr,
+                                           ListInit *CurValueCol) {
+  ListInit *RowFields = InstrMapDesc.getRowFields();
+  std::vector<Init*> KeyValue;
+
+  // Construct KeyValue using KeyInstr's values for RowFields.
+  for (unsigned j = 0, endRF = RowFields->getSize(); j < endRF; j++) {
+    Init *RowFieldsJ = RowFields->getElement(j);
+    Init *KeyInstrVal = KeyInstr->getValue(RowFieldsJ)->getValue();
+    KeyValue.push_back(KeyInstrVal);
+  }
+
+  // Get all the instructions that share the same KeyValue as the KeyInstr
+  // in RowInstrMap. We search through these instructions to find a match
+  // for the current column, i.e., the instruction which has the same values
+  // as CurValueCol for all the fields in ColFields.
+  const std::vector<Record*> &RelatedInstrVec = RowInstrMap[KeyValue];
+
+  ListInit *ColFields = InstrMapDesc.getColFields();
+  Record *MatchInstr = NULL;
+
+  for (unsigned i = 0, e = RelatedInstrVec.size(); i < e; i++) {
+    bool MatchFound = true;
+    Record *CurInstr = RelatedInstrVec[i];
+    for (unsigned j = 0, endCF = ColFields->getSize();
+        (j < endCF) && MatchFound; j++) {
+      Init *ColFieldJ = ColFields->getElement(j);
+      Init *CurInstrInit = CurInstr->getValue(ColFieldJ)->getValue();
+      std::string CurInstrVal = CurInstrInit->getAsUnquotedString();
+      Init *ColFieldJVallue = CurValueCol->getElement(j);
+      MatchFound = (CurInstrVal == ColFieldJVallue->getAsUnquotedString());
+    }
+
+    if (MatchFound) {
+      if (MatchInstr) // Already had a match
+        // Error if multiple matches are found for a column.
+        throw "Multiple matches found for `" + KeyInstr->getName() +
+              "', for the relation `" + InstrMapDesc.getName();
+      else
+        MatchInstr = CurInstr;
+    }
+  }
+  return MatchInstr;
+}
+
+//===----------------------------------------------------------------------===//
+// Emit one table per relation. Only instructions with a valid relation of a
+// given type are included in the table sorted by their enum values (opcodes).
+// Binary search is used for locating instructions in the table.
+//===----------------------------------------------------------------------===//
+
+unsigned MapTableEmitter::emitBinSearchTable(raw_ostream &OS) {
+
+  const std::vector<const CodeGenInstruction*> &NumberedInstructions =
+                                            Target.getInstructionsByEnumValue();
+  std::string TargetName = Target.getName();
+  const std::vector<ListInit*> &ValueCols = InstrMapDesc.getValueCols();
+  unsigned NumCol = ValueCols.size();
+  unsigned TotalNumInstr = NumberedInstructions.size();
+  unsigned TableSize = 0;
+
+  OS << "static const uint16_t "<<InstrMapDesc.getName();
+  // Number of columns in the table are NumCol+1 because key instructions are
+  // emitted as first column.
+  OS << "Table[]["<< NumCol+1 << "] = {\n";
+  for (unsigned i = 0; i < TotalNumInstr; i++) {
+    Record *CurInstr = NumberedInstructions[i]->TheDef;
+    std::vector<Record*> ColInstrs = MapTable[CurInstr];
+    std::string OutStr("");
+    unsigned RelExists = 0;
+    if (ColInstrs.size()) {
+      for (unsigned j = 0; j < NumCol; j++) {
+        if (ColInstrs[j] != NULL) {
+          RelExists = 1;
+          OutStr += ", ";
+          OutStr += TargetName;
+          OutStr += "::";
+          OutStr += ColInstrs[j]->getName();
+        } else { OutStr += ", -1";}
+      }
+
+      if (RelExists) {
+        OS << "  { " << TargetName << "::" << CurInstr->getName();
+        OS << OutStr <<" },\n";
+        TableSize++;
+      }
+    }
+  }
+  if (!TableSize) {
+    OS << "  { " << TargetName << "::" << "INSTRUCTION_LIST_END, ";
+    OS << TargetName << "::" << "INSTRUCTION_LIST_END }";
+  }
+  OS << "}; // End of " << InstrMapDesc.getName() << "Table\n\n";
+  return TableSize;
+}
+
+//===----------------------------------------------------------------------===//
+// Emit binary search algorithm as part of the functions used to query
+// relation tables.
+//===----------------------------------------------------------------------===//
+
+void MapTableEmitter::emitBinSearch(raw_ostream &OS, unsigned TableSize) {
+  OS << "  unsigned mid;\n";
+  OS << "  unsigned start = 0;\n";
+  OS << "  unsigned end = " << TableSize << ";\n";
+  OS << "  while (start < end) {\n";
+  OS << "    mid = start + (end - start)/2;\n";
+  OS << "    if (Opcode == " << InstrMapDesc.getName() << "Table[mid][0]) {\n";
+  OS << "      break;\n";
+  OS << "    }\n";
+  OS << "    if (Opcode < " << InstrMapDesc.getName() << "Table[mid][0])\n";
+  OS << "      end = mid;\n";
+  OS << "    else\n";
+  OS << "      start = mid + 1;\n";
+  OS << "  }\n";
+  OS << "  if (start == end)\n";
+  OS << "    return -1; // Instruction doesn't exist in this table.\n\n";
+}
+
+//===----------------------------------------------------------------------===//
+// Emit functions to query relation tables.
+//===----------------------------------------------------------------------===//
+
+void MapTableEmitter::emitMapFuncBody(raw_ostream &OS,
+                                           unsigned TableSize) {
+
+  ListInit *ColFields = InstrMapDesc.getColFields();
+  const std::vector<ListInit*> &ValueCols = InstrMapDesc.getValueCols();
+
+  // Emit binary search algorithm to locate instructions in the
+  // relation table. If found, return opcode value from the appropriate column
+  // of the table.
+  emitBinSearch(OS, TableSize);
+
+  if (ValueCols.size() > 1) {
+    for (unsigned i = 0, e = ValueCols.size(); i < e; i++) {
+      ListInit *ColumnI = ValueCols[i];
+      for (unsigned j = 0, ColSize = ColumnI->getSize(); j < ColSize; j++) {
+        std::string ColName = ColFields->getElement(j)->getAsUnquotedString();
+        OS << "  if (in" << ColName;
+        OS << " == ";
+        OS << ColName << "_" << ColumnI->getElement(j)->getAsUnquotedString();
+        if (j < ColumnI->getSize() - 1) OS << " && ";
+        else OS << ")\n";
+      }
+      OS << "    return " << InstrMapDesc.getName();
+      OS << "Table[mid]["<<i+1<<"];\n";
+    }
+    OS << "  return -1;";
+  }
+  else
+    OS << "  return " << InstrMapDesc.getName() << "Table[mid][1];\n";
+
+  OS <<"}\n\n";
+}
+
+//===----------------------------------------------------------------------===//
+// Emit relation tables and the functions to query them.
+//===----------------------------------------------------------------------===//
+
+void MapTableEmitter::emitTablesWithFunc(raw_ostream &OS) {
+
+  // Emit function name and the input parameters : mostly opcode value of the
+  // current instruction. However, if a table has multiple columns (more than 2
+  // since first column is used for the key instructions), then we also need
+  // to pass another input to indicate the column to be selected.
+
+  ListInit *ColFields = InstrMapDesc.getColFields();
+  const std::vector<ListInit*> &ValueCols = InstrMapDesc.getValueCols();
+  OS << "// "<< InstrMapDesc.getName() << "\n";
+  OS << "int "<< InstrMapDesc.getName() << "(uint16_t Opcode";
+  if (ValueCols.size() > 1) {
+    for (unsigned i = 0, e = ColFields->getSize(); i < e; i++) {
+      std::string ColName = ColFields->getElement(i)->getAsUnquotedString();
+      OS << ", enum " << ColName << " in" << ColName << ") {\n";
+    }
+  } else { OS << ") {\n"; }
+
+  // Emit map table.
+  unsigned TableSize = emitBinSearchTable(OS);
+
+  // Emit rest of the function body.
+  emitMapFuncBody(OS, TableSize);
+}
+
+//===----------------------------------------------------------------------===//
+// Emit enums for the column fields across all the instruction maps.
+//===----------------------------------------------------------------------===//
+
+static void emitEnums(raw_ostream &OS, RecordKeeper &Records) {
+
+  std::vector<Record*> InstrMapVec;
+  InstrMapVec = Records.getAllDerivedDefinitions("InstrMapping");
+  std::map<std::string, std::vector<Init*> > ColFieldValueMap;
+
+  // Iterate over all InstrMapping records and create a map between column
+  // fields and their possible values across all records.
+  for (unsigned i = 0, e = InstrMapVec.size(); i < e; i++) {
+    Record *CurMap = InstrMapVec[i];
+    ListInit *ColFields;
+    ColFields = CurMap->getValueAsListInit("ColFields");
+    ListInit *List = CurMap->getValueAsListInit("ValueCols");
+    std::vector<ListInit*> ValueCols;
+    unsigned ListSize = List->getSize();
+
+    for (unsigned j = 0; j < ListSize; j++) {
+      ListInit *ListJ = dyn_cast<ListInit>(List->getElement(j));
+
+      if (ListJ->getSize() != ColFields->getSize()) {
+        throw "Record `" + CurMap->getName() + "', field `" + "ValueCols" +
+            "' entries don't match with the entries in 'ColFields' !";
+      }
+      ValueCols.push_back(ListJ);
+    }
+
+    for (unsigned j = 0, endCF = ColFields->getSize(); j < endCF; j++) {
+      for (unsigned k = 0; k < ListSize; k++){
+        std::string ColName = ColFields->getElement(j)->getAsUnquotedString();
+        ColFieldValueMap[ColName].push_back((ValueCols[k])->getElement(j));
+      }
+    }
+  }
+
+  for (std::map<std::string, std::vector<Init*> >::iterator
+       II = ColFieldValueMap.begin(), IE = ColFieldValueMap.end();
+       II != IE; II++) {
+    std::vector<Init*> FieldValues = (*II).second;
+    unsigned FieldSize = FieldValues.size();
+
+    // Delete duplicate entries from ColFieldValueMap
+    for (unsigned i = 0; i < FieldSize - 1; i++) {
+      Init *CurVal = FieldValues[i];
+      for (unsigned j = i+1; j < FieldSize; j++) {
+        if (CurVal == FieldValues[j]) {
+          FieldValues.erase(FieldValues.begin()+j);
+        }
+      }
+    }
+
+    // Emit enumerated values for the column fields.
+    OS << "enum " << (*II).first << " {\n";
+    for (unsigned i = 0; i < FieldSize; i++) {
+      OS << "\t" << (*II).first << "_" << FieldValues[i]->getAsUnquotedString();
+      if (i != FieldValues.size() - 1)
+        OS << ",\n";
+      else
+        OS << "\n};\n\n";
+    }
+  }
+}
+
+namespace llvm {
+//===----------------------------------------------------------------------===//
+// Parse 'InstrMapping' records and use the information to form relationship
+// between instructions. These relations are emitted as a tables along with the
+// functions to query them.
+//===----------------------------------------------------------------------===//
+void EmitMapTable(RecordKeeper &Records, raw_ostream &OS) {
+  CodeGenTarget Target(Records);
+  std::string TargetName = Target.getName();
+  std::vector<Record*> InstrMapVec;
+  InstrMapVec = Records.getAllDerivedDefinitions("InstrMapping");
+
+  if (!InstrMapVec.size())
+    return;
+
+  OS << "#ifdef GET_INSTRMAP_INFO\n";
+  OS << "#undef GET_INSTRMAP_INFO\n";
+  OS << "namespace llvm {\n\n";
+  OS << "namespace " << TargetName << " {\n\n";
+
+  // Emit coulumn field names and their values as enums.
+  emitEnums(OS, Records);
+
+  // Iterate over all instruction mapping records and construct relationship
+  // maps based on the information specified there.
+  //
+  for (unsigned i = 0, e = InstrMapVec.size(); i < e; i++) {
+    MapTableEmitter IMap(Target, Records, InstrMapVec[i]);
+
+    // Build RowInstrMap to group instructions based on their values for
+    // RowFields. In the process, also collect key instructions into
+    // KeyInstrVec.
+    IMap.buildRowInstrMap();
+
+    // Build MapTable to map key instructions with the corresponding column
+    // instructions.
+    IMap.buildMapTable();
+
+    // Emit map tables and the functions to query them.
+    IMap.emitTablesWithFunc(OS);
+  }
+  OS << "} // End " << TargetName << " namespace\n";
+  OS << "} // End llvm namespace\n";
+  OS << "#endif // GET_INSTRMAP_INFO\n\n";
+}
+
+} // End llvm namespace
diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index e447c16b16..8e670e3cbc 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -16,6 +16,7 @@
 #include "CodeGenDAGPatterns.h"
 #include "CodeGenSchedule.h"
 #include "CodeGenTarget.h"
+#include "TableGenBackends.h"
 #include "SequenceToOffsetTable.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/TableGen/Record.h"
@@ -415,6 +416,7 @@ namespace llvm {
 
 void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS) {
   InstrInfoEmitter(RK).run(OS);
+  EmitMapTable(RK, OS);
 }
 
 } // End llvm namespace
diff --git a/utils/TableGen/TableGenBackends.h b/utils/TableGen/TableGenBackends.h
index 2c00c40cfe..f0d25d8a2c 100644
--- a/utils/TableGen/TableGenBackends.h
+++ b/utils/TableGen/TableGenBackends.h
@@ -74,5 +74,6 @@ void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS);
 void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS);
 void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS);
 void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS);
+void EmitMapTable(RecordKeeper &RK, raw_ostream &OS);
 
 } // End llvm namespace