1 //===- OutputSection.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_MACHO_OUTPUT_SECTION_H 10 #define LLD_MACHO_OUTPUT_SECTION_H 11 12 #include "lld/Common/LLVM.h" 13 #include "llvm/ADT/DenseMap.h" 14 15 namespace lld { 16 namespace macho { 17 18 class InputSection; 19 class OutputSegment; 20 21 // Output sections represent the finalized sections present within the final 22 // linked executable. They can represent special sections (like the symbol 23 // table), or represent coalesced sections from the various inputs given to the 24 // linker with the same segment / section name. 25 class OutputSection { 26 public: 27 enum Kind { 28 MergedKind, 29 SyntheticKind, 30 }; 31 32 OutputSection(Kind kind, StringRef name) : name(name), sectionKind(kind) {} 33 virtual ~OutputSection() = default; 34 Kind kind() const { return sectionKind; } 35 36 // These accessors will only be valid after finalizing the section. 37 uint64_t getSegmentOffset() const; 38 39 // How much space the section occupies in the address space. 40 virtual uint64_t getSize() const = 0; 41 // How much space the section occupies in the file. Most sections are copied 42 // as-is so their file size is the same as their address space size. 43 virtual uint64_t getFileSize() const { return getSize(); } 44 45 // Hidden sections omit header content, but body content may still be present. 46 virtual bool isHidden() const { return false; } 47 // Unneeded sections are omitted entirely (header and body). 48 virtual bool isNeeded() const { return true; } 49 50 // Specifically finalizes addresses and section size, not content. 51 virtual void finalize() { 52 // TODO investigate refactoring synthetic section finalization logic into 53 // overrides of this function. 54 } 55 56 virtual void writeTo(uint8_t *buf) const = 0; 57 58 StringRef name; 59 OutputSegment *parent = nullptr; 60 61 uint32_t index = 0; 62 uint64_t addr = 0; 63 uint64_t fileOff = 0; 64 uint32_t align = 1; 65 uint32_t flags = 0; 66 uint32_t reserved1 = 0; 67 uint32_t reserved2 = 0; 68 69 private: 70 Kind sectionKind; 71 }; 72 73 } // namespace macho 74 } // namespace lld 75 76 #endif 77