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/ADT/ArrayRef.h"
20 #include "llvm/CodeGen/AsmPrinter.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/Support/LEB128.h"
23 #include <string>
24 
25 namespace llvm {
26 class ByteStreamer {
27  protected:
28   ~ByteStreamer() = default;
29   ByteStreamer(const ByteStreamer&) = default;
30   ByteStreamer() = default;
31 
32  public:
33   // For now we're just handling the calls we need for dwarf emission/hashing.
34   virtual void EmitInt8(uint8_t Byte, const Twine &Comment = "") = 0;
35   virtual void EmitSLEB128(uint64_t DWord, const Twine &Comment = "") = 0;
36   virtual void EmitULEB128(uint64_t DWord, const Twine &Comment = "") = 0;
37 };
38 
39 class APByteStreamer final : public ByteStreamer {
40 private:
41   AsmPrinter &AP;
42 
43 public:
APByteStreamer(AsmPrinter & Asm)44   APByteStreamer(AsmPrinter &Asm) : AP(Asm) {}
EmitInt8(uint8_t Byte,const Twine & Comment)45   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
46     AP.OutStreamer->AddComment(Comment);
47     AP.EmitInt8(Byte);
48   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)49   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
50     AP.OutStreamer->AddComment(Comment);
51     AP.EmitSLEB128(DWord);
52   }
EmitULEB128(uint64_t DWord,const Twine & Comment)53   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
54     AP.OutStreamer->AddComment(Comment);
55     AP.EmitULEB128(DWord);
56   }
57 };
58 
59 class HashingByteStreamer final : public ByteStreamer {
60  private:
61   DIEHash &Hash;
62  public:
HashingByteStreamer(DIEHash & H)63  HashingByteStreamer(DIEHash &H) : Hash(H) {}
EmitInt8(uint8_t Byte,const Twine & Comment)64   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
65     Hash.update(Byte);
66   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)67   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
68     Hash.addSLEB128(DWord);
69   }
EmitULEB128(uint64_t DWord,const Twine & Comment)70   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
71     Hash.addULEB128(DWord);
72   }
73 };
74 
75 class BufferByteStreamer final : public ByteStreamer {
76 private:
77   SmallVectorImpl<char> &Buffer;
78   SmallVectorImpl<std::string> &Comments;
79 
80   /// \brief Only verbose textual output needs comments.  This will be set to
81   /// true for that case, and false otherwise.  If false, comments passed in to
82   /// the emit methods will be ignored.
83   bool GenerateComments;
84 
85 public:
BufferByteStreamer(SmallVectorImpl<char> & Buffer,SmallVectorImpl<std::string> & Comments,bool GenerateComments)86   BufferByteStreamer(SmallVectorImpl<char> &Buffer,
87                      SmallVectorImpl<std::string> &Comments,
88                      bool GenerateComments)
89   : Buffer(Buffer), Comments(Comments), GenerateComments(GenerateComments) {}
EmitInt8(uint8_t Byte,const Twine & Comment)90   void EmitInt8(uint8_t Byte, const Twine &Comment) override {
91     Buffer.push_back(Byte);
92     if (GenerateComments)
93       Comments.push_back(Comment.str());
94   }
EmitSLEB128(uint64_t DWord,const Twine & Comment)95   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
96     raw_svector_ostream OSE(Buffer);
97     encodeSLEB128(DWord, OSE);
98     if (GenerateComments)
99       Comments.push_back(Comment.str());
100   }
EmitULEB128(uint64_t DWord,const Twine & Comment)101   void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
102     raw_svector_ostream OSE(Buffer);
103     encodeULEB128(DWord, OSE);
104     if (GenerateComments)
105       Comments.push_back(Comment.str());
106   }
107 };
108 
109 }
110 
111 #endif
112