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 = "", 35 unsigned PadTo = 0) = 0; 36 }; 37 38 class APByteStreamer final : public ByteStreamer { 39 private: 40 AsmPrinter &AP; 41 42 public: 43 APByteStreamer(AsmPrinter &Asm) : AP(Asm) {} 44 void EmitInt8(uint8_t Byte, const Twine &Comment) override { 45 AP.OutStreamer->AddComment(Comment); 46 AP.emitInt8(Byte); 47 } 48 void emitSLEB128(uint64_t DWord, const Twine &Comment) override { 49 AP.OutStreamer->AddComment(Comment); 50 AP.emitSLEB128(DWord); 51 } 52 void emitULEB128(uint64_t DWord, const Twine &Comment, 53 unsigned PadTo) override { 54 AP.OutStreamer->AddComment(Comment); 55 AP.emitULEB128(DWord, nullptr, PadTo); 56 } 57 }; 58 59 class HashingByteStreamer final : public ByteStreamer { 60 private: 61 DIEHash &Hash; 62 public: 63 HashingByteStreamer(DIEHash &H) : Hash(H) {} 64 void EmitInt8(uint8_t Byte, const Twine &Comment) override { 65 Hash.update(Byte); 66 } 67 void emitSLEB128(uint64_t DWord, const Twine &Comment) override { 68 Hash.addSLEB128(DWord); 69 } 70 void emitULEB128(uint64_t DWord, const Twine &Comment, 71 unsigned PadTo) override { 72 Hash.addULEB128(DWord); 73 } 74 }; 75 76 class BufferByteStreamer final : public ByteStreamer { 77 private: 78 SmallVectorImpl<char> &Buffer; 79 std::vector<std::string> &Comments; 80 81 public: 82 /// Only verbose textual output needs comments. This will be set to 83 /// true for that case, and false otherwise. If false, comments passed in to 84 /// the emit methods will be ignored. 85 const bool GenerateComments; 86 87 BufferByteStreamer(SmallVectorImpl<char> &Buffer, 88 std::vector<std::string> &Comments, bool GenerateComments) 89 : Buffer(Buffer), Comments(Comments), GenerateComments(GenerateComments) { 90 } 91 void EmitInt8(uint8_t Byte, const Twine &Comment) override { 92 Buffer.push_back(Byte); 93 if (GenerateComments) 94 Comments.push_back(Comment.str()); 95 } 96 void emitSLEB128(uint64_t DWord, const Twine &Comment) override { 97 raw_svector_ostream OSE(Buffer); 98 unsigned Length = encodeSLEB128(DWord, OSE); 99 if (GenerateComments) { 100 Comments.push_back(Comment.str()); 101 // Add some empty comments to keep the Buffer and Comments vectors aligned 102 // with each other. 103 for (size_t i = 1; i < Length; ++i) 104 Comments.push_back(""); 105 106 } 107 } 108 void emitULEB128(uint64_t DWord, const Twine &Comment, 109 unsigned PadTo) override { 110 raw_svector_ostream OSE(Buffer); 111 unsigned Length = encodeULEB128(DWord, OSE, PadTo); 112 if (GenerateComments) { 113 Comments.push_back(Comment.str()); 114 // Add some empty comments to keep the Buffer and Comments vectors aligned 115 // with each other. 116 for (size_t i = 1; i < Length; ++i) 117 Comments.push_back(""); 118 119 } 120 } 121 }; 122 123 } 124 125 #endif 126