1//===- MCSectionELF.h - ELF Machine Code Sections ---------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file declares the MCSectionELF class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_MC_MCSECTIONELF_H
15#define LLVM_MC_MCSECTIONELF_H
16
17#include "llvm/ADT/StringRef.h"
18#include "llvm/MC/MCSection.h"
19#include "llvm/MC/MCSymbolELF.h"
20#include "llvm/MC/SectionKind.h"
21
22namespace llvm {
23
24class MCSymbol;
25
26/// This represents a section on linux, lots of unix variants and some bare
27/// metal systems.
28class MCSectionELF final : public MCSection {
29  /// This is the name of the section.  The referenced memory is owned by
30  /// TargetLoweringObjectFileELF's ELFUniqueMap.
31  StringRef SectionName;
32
33  /// This is the sh_type field of a section, drawn from the enums below.
34  unsigned Type;
35
36  /// This is the sh_flags field of a section, drawn from the enums below.
37  unsigned Flags;
38
39  unsigned UniqueID;
40
41  /// The size of each entry in this section. This size only makes sense for
42  /// sections that contain fixed-sized entries. If a section does not contain
43  /// fixed-sized entries 'EntrySize' will be 0.
44  unsigned EntrySize;
45
46  const MCSymbolELF *Group;
47
48  /// sh_info for SHF_LINK_ORDER (can be null).
49  const MCSymbol *AssociatedSymbol;
50
51private:
52  friend class MCContext;
53
54  MCSectionELF(StringRef Section, unsigned type, unsigned flags, SectionKind K,
55               unsigned entrySize, const MCSymbolELF *group, unsigned UniqueID,
56               MCSymbol *Begin, const MCSymbolELF *AssociatedSymbol)
57      : MCSection(SV_ELF, K, Begin), SectionName(Section), Type(type),
58        Flags(flags), UniqueID(UniqueID), EntrySize(entrySize), Group(group),
59        AssociatedSymbol(AssociatedSymbol) {
60    if (Group)
61      Group->setIsSignature();
62  }
63
64  void setSectionName(StringRef Name) { SectionName = Name; }
65
66public:
67  ~MCSectionELF();
68
69  /// Decides whether a '.section' directive should be printed before the
70  /// section name
71  bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
72
73  StringRef getSectionName() const { return SectionName; }
74  unsigned getType() const { return Type; }
75  unsigned getFlags() const { return Flags; }
76  unsigned getEntrySize() const { return EntrySize; }
77  void setFlags(unsigned F) { Flags = F; }
78  const MCSymbolELF *getGroup() const { return Group; }
79
80  void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
81                            raw_ostream &OS,
82                            const MCExpr *Subsection) const override;
83  bool UseCodeAlign() const override;
84  bool isVirtualSection() const override;
85
86  bool isUnique() const { return UniqueID != ~0U; }
87  unsigned getUniqueID() const { return UniqueID; }
88
89  const MCSection *getAssociatedSection() const { return &AssociatedSymbol->getSection(); }
90  const MCSymbol *getAssociatedSymbol() const { return AssociatedSymbol; }
91
92  static bool classof(const MCSection *S) {
93    return S->getVariant() == SV_ELF;
94  }
95};
96
97} // end namespace llvm
98
99#endif // LLVM_MC_MCSECTIONELF_H
100