MCSectionELF.h revision ed84062812c7b8a82d0e8128a22aa1aa07a14d79 
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#include "llvm/ADT/StringRef.h"
20
21namespace llvm {
22
23class MCSymbol;
24
25/// MCSectionELF - This represents a section on linux, lots of unix variants
26/// and some bare metal systems.
27class MCSectionELF : public MCSection {
28  /// SectionName - This is the name of the section.  The referenced memory is
29  /// owned by TargetLoweringObjectFileELF's ELFUniqueMap.
30  StringRef SectionName;
31
32  /// Type - This is the sh_type field of a section, drawn from the enums below.
33  unsigned Type;
34
35  /// Flags - This is the sh_flags field of a section, drawn from the enums.
36  /// below.
37  unsigned Flags;
38
39  /// EntrySize - The size of each entry in this section. This size only
40  /// makes sense for sections that contain fixed-sized entries. If a
41  /// section does not contain fixed-sized entries 'EntrySize' will be 0.
42  unsigned EntrySize;
43
44  const MCSymbol *Group;
45
46private:
47  friend class MCContext;
48  MCSectionELF(StringRef Section, unsigned type, unsigned flags,
49               SectionKind K, unsigned entrySize, const MCSymbol *group)
50    : MCSection(SV_ELF, K), SectionName(Section), Type(type), Flags(flags),
51      EntrySize(entrySize), Group(group) {}
52  ~MCSectionELF();
53public:
54
55  /// ShouldOmitSectionDirective - Decides whether a '.section' directive
56  /// should be printed before the section name
57  bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
58
59  StringRef getSectionName() const { return SectionName; }
60  unsigned getType() const { return Type; }
61  unsigned getFlags() const { return Flags; }
62  unsigned getEntrySize() const { return EntrySize; }
63  const MCSymbol *getGroup() const { return Group; }
64
65  void PrintSwitchToSection(const MCAsmInfo &MAI,
66                            raw_ostream &OS) const;
67  virtual bool UseCodeAlign() const;
68  virtual bool isVirtualSection() const;
69
70  /// isBaseAddressKnownZero - We know that non-allocatable sections (like
71  /// debug info) have a base of zero.
72  virtual bool isBaseAddressKnownZero() const {
73    return (getFlags() & ELF::SHF_ALLOC) == 0;
74  }
75
76  static bool classof(const MCSection *S) {
77    return S->getVariant() == SV_ELF;
78  }
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