lib/CodeGen/AsmPrinter/ByteStreamer.h

   1 //===-- llvm/CodeGen/ByteStreamer.h - ByteStreamer class --------*- 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 contains a class that can take bytes that would normally be
  10 // streamed via the AsmPrinter.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
  15 #define LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
  16
  17 #include "DIEHash.h"
  18 #include "llvm/CodeGen/AsmPrinter.h"
  19 #include "llvm/MC/MCStreamer.h"
  20 #include "llvm/Support/LEB128.h"
  21 #include <string>
  22
  23 namespace llvm {
  24 class ByteStreamer {
  25  protected:
  26   ~ByteStreamer() = default;
  27   ByteStreamer(const ByteStreamer&) = default;
  28   ByteStreamer() = default;
  29
  30  public:
  31   // For now we're just handling the calls we need for dwarf emission/hashing.
  32   virtual void EmitInt8(uint8_t Byte, const Twine &Comment = "") = 0;
  33   virtual void EmitSLEB128(uint64_t DWord, const Twine &Comment = "") = 0;
  34   virtual void EmitULEB128(uint64_t DWord, const Twine &Comment = "", unsigned PadTo = 0) = 0;
  35 };
  36
  37 class APByteStreamer final : public ByteStreamer {
  38 private:
  39   AsmPrinter &AP;
  40
  41 public:
  42   APByteStreamer(AsmPrinter &Asm) : AP(Asm) {}
  43   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
  44     AP.OutStreamer->AddComment(Comment);
  45     AP.emitInt8(Byte);
  46   }
  47   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
  48     AP.OutStreamer->AddComment(Comment);
  49     AP.EmitSLEB128(DWord);
  50   }
  51   void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
  52     AP.OutStreamer->AddComment(Comment);
  53     AP.EmitULEB128(DWord);
  54   }
  55 };
  56
  57 class HashingByteStreamer final : public ByteStreamer {
  58  private:
  59   DIEHash &Hash;
  60  public:
  61  HashingByteStreamer(DIEHash &H) : Hash(H) {}
  62   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
  63     Hash.update(Byte);
  64   }
  65   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
  66     Hash.addSLEB128(DWord);
  67   }
  68   void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
  69     Hash.addULEB128(DWord);
  70   }
  71 };
  72
  73 class BufferByteStreamer final : public ByteStreamer {
  74 private:
  75   SmallVectorImpl<char> &Buffer;
  76   std::vector<std::string> &Comments;
  77
  78 public:
  79   /// Only verbose textual output needs comments.  This will be set to
  80   /// true for that case, and false otherwise.  If false, comments passed in to
  81   /// the emit methods will be ignored.
  82   const bool GenerateComments;
  83
  84   BufferByteStreamer(SmallVectorImpl<char> &Buffer,
  85                      std::vector<std::string> &Comments, bool GenerateComments)
  86       : Buffer(Buffer), Comments(Comments), GenerateComments(GenerateComments) {
  87   }
  88   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
  89     Buffer.push_back(Byte);
  90     if (GenerateComments)
  91       Comments.push_back(Comment.str());
  92   }
  93   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
  94     raw_svector_ostream OSE(Buffer);
  95     unsigned Length = encodeSLEB128(DWord, OSE);
  96     if (GenerateComments) {
  97       Comments.push_back(Comment.str());
  98       // Add some empty comments to keep the Buffer and Comments vectors aligned
  99       // with each other.
 100       for (size_t i = 1; i < Length; ++i)
 101         Comments.push_back("");
 102
 103     }
 104   }
 105   void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
 106     raw_svector_ostream OSE(Buffer);
 107     unsigned Length = encodeULEB128(DWord, OSE, PadTo);
 108     if (GenerateComments) {
 109       Comments.push_back(Comment.str());
 110       // Add some empty comments to keep the Buffer and Comments vectors aligned
 111       // with each other.
 112       for (size_t i = 1; i < Length; ++i)
 113         Comments.push_back("");
 114
 115     }
 116   }
 117 };
 118
 119 }
 120
 121 #endif