1 //===- Writer.h -------------------------------------------------*- 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 #ifndef LLD_COFF_WRITER_H 10 #define LLD_COFF_WRITER_H 11 12 #include "Chunks.h" 13 #include "llvm/ADT/StringRef.h" 14 #include "llvm/Object/COFF.h" 15 #include <chrono> 16 #include <cstdint> 17 #include <vector> 18 19 namespace lld { 20 namespace coff { 21 static const int pageSize = 4096; 22 23 void writeResult(); 24 25 class PartialSection { 26 public: 27 PartialSection(StringRef n, uint32_t chars) 28 : name(n), characteristics(chars) {} 29 StringRef name; 30 unsigned characteristics; 31 std::vector<Chunk *> chunks; 32 }; 33 34 // OutputSection represents a section in an output file. It's a 35 // container of chunks. OutputSection and Chunk are 1:N relationship. 36 // Chunks cannot belong to more than one OutputSections. The writer 37 // creates multiple OutputSections and assign them unique, 38 // non-overlapping file offsets and RVAs. 39 class OutputSection { 40 public: 41 OutputSection(llvm::StringRef n, uint32_t chars) : name(n) { 42 header.Characteristics = chars; 43 } 44 void addChunk(Chunk *c); 45 void insertChunkAtStart(Chunk *c); 46 void merge(OutputSection *other); 47 void setPermissions(uint32_t c); 48 uint64_t getRVA() { return header.VirtualAddress; } 49 uint64_t getFileOff() { return header.PointerToRawData; } 50 void writeHeaderTo(uint8_t *buf); 51 void addContributingPartialSection(PartialSection *sec); 52 53 // Clear the output sections static container. 54 static void clear(); 55 56 // Returns the size of this section in an executable memory image. 57 // This may be smaller than the raw size (the raw size is multiple 58 // of disk sector size, so there may be padding at end), or may be 59 // larger (if that's the case, the loader reserves spaces after end 60 // of raw data). 61 uint64_t getVirtualSize() { return header.VirtualSize; } 62 63 // Returns the size of the section in the output file. 64 uint64_t getRawSize() { return header.SizeOfRawData; } 65 66 // Set offset into the string table storing this section name. 67 // Used only when the name is longer than 8 bytes. 68 void setStringTableOff(uint32_t v) { stringTableOff = v; } 69 70 // N.B. The section index is one based. 71 uint32_t sectionIndex = 0; 72 73 llvm::StringRef name; 74 llvm::object::coff_section header = {}; 75 76 std::vector<Chunk *> chunks; 77 std::vector<Chunk *> origChunks; 78 79 std::vector<PartialSection *> contribSections; 80 81 private: 82 uint32_t stringTableOff = 0; 83 }; 84 85 } // namespace coff 86 } // namespace lld 87 88 #endif 89