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 19namespace lld::coff { 20static const int pageSize = 4096; 21class COFFLinkerContext; 22 23void writeResult(COFFLinkerContext &ctx); 24 25class PartialSection { 26public: 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. 39class OutputSection { 40public: 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() const { return header.VirtualAddress; } 49 uint64_t getFileOff() const { return header.PointerToRawData; } 50 void writeHeaderTo(uint8_t *buf, bool isDebug); 51 void addContributingPartialSection(PartialSection *sec); 52 53 // Returns the size of this section in an executable memory image. 54 // This may be smaller than the raw size (the raw size is multiple 55 // of disk sector size, so there may be padding at end), or may be 56 // larger (if that's the case, the loader reserves spaces after end 57 // of raw data). 58 uint64_t getVirtualSize() { return header.VirtualSize; } 59 60 // Returns the size of the section in the output file. 61 uint64_t getRawSize() { return header.SizeOfRawData; } 62 63 // Set offset into the string table storing this section name. 64 // Used only when the name is longer than 8 bytes. 65 void setStringTableOff(uint32_t v) { stringTableOff = v; } 66 67 bool isCodeSection() const { 68 return (header.Characteristics & llvm::COFF::IMAGE_SCN_CNT_CODE) && 69 (header.Characteristics & llvm::COFF::IMAGE_SCN_MEM_READ) && 70 (header.Characteristics & llvm::COFF::IMAGE_SCN_MEM_EXECUTE); 71 } 72 73 // N.B. The section index is one based. 74 uint32_t sectionIndex = 0; 75 76 llvm::StringRef name; 77 llvm::object::coff_section header = {}; 78 79 std::vector<Chunk *> chunks; 80 std::vector<Chunk *> origChunks; 81 82 std::vector<PartialSection *> contribSections; 83 84private: 85 uint32_t stringTableOff = 0; 86}; 87 88} // namespace lld::coff 89 90#endif 91