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1 //===-- llvm/CodeGen/ByteStreamer.h - ByteStreamer class --------*- 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 // This file contains a class that can take bytes that would normally be
11 // streamed via the AsmPrinter.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
16 #define LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
17 
18 #include "DIEHash.h"
19 #include "llvm/CodeGen/AsmPrinter.h"
20 #include "llvm/MC/MCStreamer.h"
21 #include "llvm/Support/LEB128.h"
22 #include <string>
23 
24 namespace llvm {
25 class ByteStreamer {
26  protected:
27   ~ByteStreamer() = default;
28   ByteStreamer(const ByteStreamer&) = default;
29   ByteStreamer() = default;
30 
31  public:
32   // For now we're just handling the calls we need for dwarf emission/hashing.
33   virtual void EmitInt8(uint8_t Byte, const Twine &Comment = "") = 0;
34   virtual void EmitSLEB128(uint64_t DWord, const Twine &Comment = "") = 0;
35   virtual void EmitULEB128(uint64_t DWord, const Twine &Comment = "") = 0;
36 };
37 
38 class APByteStreamer final : public ByteStreamer {
39 private:
40   AsmPrinter &AP;
41 
42 public:
APByteStreamer(AsmPrinter & Asm)43   APByteStreamer(AsmPrinter &Asm) : AP(Asm) {}
EmitInt8(uint8_t Byte,const Twine & Comment)44   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
45     AP.OutStreamer->AddComment(Comment);
46     AP.EmitInt8(Byte);
47   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)48   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
49     AP.OutStreamer->AddComment(Comment);
50     AP.EmitSLEB128(DWord);
51   }
EmitULEB128(uint64_t DWord,const Twine & Comment)52   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
53     AP.OutStreamer->AddComment(Comment);
54     AP.EmitULEB128(DWord);
55   }
56 };
57 
58 class HashingByteStreamer final : public ByteStreamer {
59  private:
60   DIEHash &Hash;
61  public:
HashingByteStreamer(DIEHash & H)62  HashingByteStreamer(DIEHash &H) : Hash(H) {}
EmitInt8(uint8_t Byte,const Twine & Comment)63   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
64     Hash.update(Byte);
65   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)66   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
67     Hash.addSLEB128(DWord);
68   }
EmitULEB128(uint64_t DWord,const Twine & Comment)69   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
70     Hash.addULEB128(DWord);
71   }
72 };
73 
74 class BufferByteStreamer final : public ByteStreamer {
75 private:
76   SmallVectorImpl<char> &Buffer;
77   SmallVectorImpl<std::string> &Comments;
78 
79   /// \brief 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   bool GenerateComments;
83 
84 public:
BufferByteStreamer(SmallVectorImpl<char> & Buffer,SmallVectorImpl<std::string> & Comments,bool GenerateComments)85   BufferByteStreamer(SmallVectorImpl<char> &Buffer,
86                      SmallVectorImpl<std::string> &Comments,
87                      bool GenerateComments)
88   : Buffer(Buffer), Comments(Comments), GenerateComments(GenerateComments) {}
EmitInt8(uint8_t Byte,const Twine & Comment)89   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
90     Buffer.push_back(Byte);
91     if (GenerateComments)
92       Comments.push_back(Comment.str());
93   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)94   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
95     raw_svector_ostream OSE(Buffer);
96     encodeSLEB128(DWord, OSE);
97     if (GenerateComments)
98       Comments.push_back(Comment.str());
99   }
EmitULEB128(uint64_t DWord,const Twine & Comment)100   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
101     raw_svector_ostream OSE(Buffer);
102     encodeULEB128(DWord, OSE);
103     if (GenerateComments)
104       Comments.push_back(Comment.str());
105   }
106 };
107 
108 }
109 
110 #endif
111