include/llvm/MC/MCSectionELF.h

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