utils/TableGen/FixedLenDecoderEmitter.h

   1 //===------------ FixedLenDecoderEmitter.h - Decoder Generator --*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // It contains the tablegen backend that emits the decoder functions for
  11 // targets with fixed length instruction set.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef FixedLenDECODEREMITTER_H
  16 #define FixedLenDECODEREMITTER_H
  17
  18 #include "CodeGenTarget.h"
  19
  20 #include "llvm/TableGen/TableGenBackend.h"
  21 #include "llvm/Support/DataTypes.h"
  22
  23 namespace llvm {
  24
  25 struct EncodingField {
  26   unsigned Base, Width, Offset;
  27   EncodingField(unsigned B, unsigned W, unsigned O)
  28     : Base(B), Width(W), Offset(O) { }
  29 };
  30
  31 struct OperandInfo {
  32   std::vector<EncodingField> Fields;
  33   std::string Decoder;
  34
  35   OperandInfo(std::string D)
  36     : Decoder(D) { }
  37
  38   void addField(unsigned Base, unsigned Width, unsigned Offset) {
  39     Fields.push_back(EncodingField(Base, Width, Offset));
  40   }
  41
  42   unsigned numFields() { return Fields.size(); }
  43
  44   typedef std::vector<EncodingField>::iterator iterator;
  45
  46   iterator begin() { return Fields.begin(); }
  47   iterator end()   { return Fields.end();   }
  48 };
  49
  50 class FixedLenDecoderEmitter : public TableGenBackend {
  51 public:
  52   FixedLenDecoderEmitter(RecordKeeper &R,
  53                          std::string PredicateNamespace,
  54                          std::string GPrefix  = "if (",
  55                          std::string GPostfix = " == MCDisassembler::Fail) return MCDisassembler::Fail;",
  56                          std::string ROK      = "MCDisassembler::Success",
  57                          std::string RFail    = "MCDisassembler::Fail",
  58                          std::string L        = "") :
  59     Records(R), Target(R),
  60     NumberedInstructions(Target.getInstructionsByEnumValue()),
  61     PredicateNamespace(PredicateNamespace),
  62     GuardPrefix(GPrefix), GuardPostfix(GPostfix),
  63     ReturnOK(ROK), ReturnFail(RFail), Locals(L) {}
  64
  65   // run - Output the code emitter
  66   void run(raw_ostream &o);
  67
  68 private:
  69   RecordKeeper &Records;
  70   CodeGenTarget Target;
  71   std::vector<const CodeGenInstruction*> NumberedInstructions;
  72   std::vector<unsigned> Opcodes;
  73   std::map<unsigned, std::vector<OperandInfo> > Operands;
  74 public:
  75   std::string PredicateNamespace;
  76   std::string GuardPrefix, GuardPostfix;
  77   std::string ReturnOK, ReturnFail;
  78   std::string Locals;
  79 };
  80
  81 } // end llvm namespace
  82
  83 #endif