llvm/utils/TableGen/VarLenCodeEmitterGen.h

   1 //===- VarLenCodeEmitterGen.h - CEG for variable-length insts ---*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file declare the CodeEmitterGen component for variable-length
  10 // instructions. See the .cpp file for more details.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_UTILS_TABLEGEN_VARLENCODEEMITTERGEN_H
  15 #define LLVM_UTILS_TABLEGEN_VARLENCODEEMITTERGEN_H
  16
  17 #include "llvm/TableGen/Record.h"
  18
  19 namespace llvm {
  20
  21 struct EncodingSegment {
  22   unsigned BitWidth;
  23   const Init *Value;
  24   StringRef CustomEncoder = "";
  25   StringRef CustomDecoder = "";
  26 };
  27
  28 class VarLenInst {
  29   const RecordVal *TheDef;
  30   size_t NumBits;
  31
  32   // Set if any of the segment is not fixed value.
  33   bool HasDynamicSegment;
  34
  35   SmallVector<EncodingSegment, 4> Segments;
  36
  37   void buildRec(const DagInit *DI);
  38
  39 public:
  40   VarLenInst() : TheDef(nullptr), NumBits(0U), HasDynamicSegment(false) {}
  41
  42   explicit VarLenInst(const DagInit *DI, const RecordVal *TheDef);
  43
  44   /// Number of bits
  45   size_t size() const { return NumBits; }
  46
  47   using const_iterator = decltype(Segments)::const_iterator;
  48
  49   const_iterator begin() const { return Segments.begin(); }
  50   const_iterator end() const { return Segments.end(); }
  51   size_t getNumSegments() const { return Segments.size(); }
  52
  53   bool isFixedValueOnly() const { return !HasDynamicSegment; }
  54 };
  55
  56 void emitVarLenCodeEmitter(RecordKeeper &R, raw_ostream &OS);
  57
  58 } // end namespace llvm
  59 #endif