MCSectionELF.h revision ba9934648f1b8f5b1749548963f385f1147c1f68 
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/MC/MCSection.h"
18#include "llvm/Support/ELF.h"
19
20namespace llvm {
21
22class MCSymbol;
23
24/// MCSectionELF - This represents a section on linux, lots of unix variants
25/// and some bare metal systems.
26class MCSectionELF : public MCSection {
27  /// SectionName - This is the name of the section.  The referenced memory is
28  /// owned by TargetLoweringObjectFileELF's ELFUniqueMap.
29  StringRef SectionName;
30
31  /// Type - This is the sh_type field of a section, drawn from the enums below.
32  unsigned Type;
33
34  /// Flags - This is the sh_flags field of a section, drawn from the enums.
35  /// below.
36  unsigned Flags;
37
38  /// EntrySize - The size of each entry in this section. This size only
39  /// makes sense for sections that contain fixed-sized entries. If a
40  /// section does not contain fixed-sized entries 'EntrySize' will be 0.
41  unsigned EntrySize;
42
43  const MCSymbol *Group;
44
45private:
46  friend class MCContext;
47  MCSectionELF(StringRef Section, unsigned type, unsigned flags,
48               SectionKind K, unsigned entrySize, const MCSymbol *group)
49    : MCSection(SV_ELF, K), SectionName(Section), Type(type), Flags(flags),
50      EntrySize(entrySize), Group(group) {}
51  ~MCSectionELF();
52public:
53
54  /// ShouldOmitSectionDirective - Decides whether a '.section' directive
55  /// should be printed before the section name
56  bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
57
58  StringRef getSectionName() const { return SectionName; }
59  unsigned getType() const { return Type; }
60  unsigned getFlags() const { return Flags; }
61  unsigned getEntrySize() const { return EntrySize; }
62  const MCSymbol *getGroup() const { return Group; }
63
64  void PrintSwitchToSection(const MCAsmInfo &MAI,
65                            raw_ostream &OS) const;
66  virtual bool UseCodeAlign() const;
67  virtual bool isVirtualSection() const;
68
69  /// isBaseAddressKnownZero - We know that non-allocatable sections (like
70  /// debug info) have a base of zero.
71  virtual bool isBaseAddressKnownZero() const {
72    return (getFlags() & ELF::SHF_ALLOC) == 0;
73  }
74
75  static bool classof(const MCSection *S) {
76    return S->getVariant() == SV_ELF;
77  }
78  static bool classof(const MCSectionELF *) { return true; }
79
80  // Return the entry size for sections with fixed-width data.
81  static unsigned DetermineEntrySize(SectionKind Kind);
82
83};
84
85} // end namespace llvm
86
87#endif
88