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

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source code of lld/COFF/Writer.h