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/Twine.h" 18 #include "llvm/MC/MCSection.h" 19 #include "llvm/MC/MCSymbol.h" 20 #include "llvm/Support/Debug.h" 21 #include "llvm/Support/ELF.h" 22 #include "llvm/Support/raw_ostream.h" 23 24 namespace llvm { 25 26 class MCSymbol; 27 28 /// MCSectionELF - This represents a section on linux, lots of unix variants 29 /// and some bare metal systems. 30 class MCSectionELF : public MCSection { 31 /// SectionName - This is the name of the section. The referenced memory is 32 /// owned by TargetLoweringObjectFileELF's ELFUniqueMap. 33 StringRef SectionName; 34 35 /// Type - This is the sh_type field of a section, drawn from the enums below. 36 unsigned Type; 37 38 /// Flags - This is the sh_flags field of a section, drawn from the enums. 39 /// below. 40 unsigned Flags; 41 42 /// EntrySize - The size of each entry in this section. This size only 43 /// makes sense for sections that contain fixed-sized entries. If a 44 /// section does not contain fixed-sized entries 'EntrySize' will be 0. 45 unsigned EntrySize; 46 47 const MCSymbol *Group; 48 49 private: 50 friend class MCContext; 51 MCSectionELF(StringRef Section, unsigned type, unsigned flags, 52 SectionKind K, unsigned entrySize, const MCSymbol *group) 53 : MCSection(SV_ELF, K), SectionName(Section), Type(type), Flags(flags), 54 EntrySize(entrySize), Group(group) {} 55 ~MCSectionELF(); 56 57 void setSectionName(StringRef Name) { SectionName = Name; } 58 59 public: 60 61 /// ShouldOmitSectionDirective - Decides whether a '.section' directive 62 /// should be printed before the section name 63 bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const; 64 65 StringRef getSectionName() const { return SectionName; } 66 std::string getLabelBeginName() const override { 67 if (Group) 68 return (SectionName.str() + '_' + Group->getName() + "_begin").str(); 69 return SectionName.str() + "_begin"; 70 } 71 std::string getLabelEndName() const override { 72 if (Group) 73 return (SectionName.str() + '_' + Group->getName() + "_end").str(); 74 return SectionName.str() + "_end"; 75 } 76 unsigned getType() const { return Type; } 77 unsigned getFlags() const { return Flags; } 78 unsigned getEntrySize() const { return EntrySize; } 79 const MCSymbol *getGroup() const { return Group; } 80 81 void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS, 82 const MCExpr *Subsection) const override; 83 bool UseCodeAlign() const override; 84 bool isVirtualSection() const override; 85 86 /// isBaseAddressKnownZero - We know that non-allocatable sections (like 87 /// debug info) have a base of zero. 88 bool isBaseAddressKnownZero() const override { 89 return (getFlags() & ELF::SHF_ALLOC) == 0; 90 } 91 92 static bool classof(const MCSection *S) { 93 return S->getVariant() == SV_ELF; 94 } 95 96 // Return the entry size for sections with fixed-width data. 97 static unsigned DetermineEntrySize(SectionKind Kind); 98 99 }; 100 101 } // end namespace llvm 102 103 #endif 104
