1 //===- MCSectionCOFF.h - COFF 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 MCSectionCOFF class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_MC_MCSECTIONCOFF_H 15 #define LLVM_MC_MCSECTIONCOFF_H 16 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/MC/MCSection.h" 19 20 namespace llvm { 21 class MCSymbol; 22 23 /// This represents a section on Windows 24 class MCSectionCOFF final : public MCSection { 25 // The memory for this string is stored in the same MCContext as *this. 26 StringRef SectionName; 27 28 // FIXME: The following fields should not be mutable, but are for now so the 29 // asm parser can honor the .linkonce directive. 30 31 /// This is the Characteristics field of a section, drawn from the enums 32 /// below. 33 mutable unsigned Characteristics; 34 35 /// The unique IDs used with the .pdata and .xdata sections created internally 36 /// by the assembler. This ID is used to ensure that for every .text section, 37 /// there is exactly one .pdata and one .xdata section, which is required by 38 /// the Microsoft incremental linker. This data is mutable because this ID is 39 /// not notionally part of the section. 40 mutable unsigned WinCFISectionID = ~0U; 41 42 /// The COMDAT symbol of this section. Only valid if this is a COMDAT section. 43 /// Two COMDAT sections are merged if they have the same COMDAT symbol. 44 MCSymbol *COMDATSymbol; 45 46 /// This is the Selection field for the section symbol, if it is a COMDAT 47 /// section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0 48 mutable int Selection; 49 50 private: 51 friend class MCContext; MCSectionCOFF(StringRef Section,unsigned Characteristics,MCSymbol * COMDATSymbol,int Selection,SectionKind K,MCSymbol * Begin)52 MCSectionCOFF(StringRef Section, unsigned Characteristics, 53 MCSymbol *COMDATSymbol, int Selection, SectionKind K, 54 MCSymbol *Begin) 55 : MCSection(SV_COFF, K, Begin), SectionName(Section), 56 Characteristics(Characteristics), COMDATSymbol(COMDATSymbol), 57 Selection(Selection) { 58 assert((Characteristics & 0x00F00000) == 0 && 59 "alignment must not be set upon section creation"); 60 } 61 62 public: 63 ~MCSectionCOFF(); 64 65 /// Decides whether a '.section' directive should be printed before the 66 /// section name 67 bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const; 68 getSectionName()69 StringRef getSectionName() const { return SectionName; } getCharacteristics()70 unsigned getCharacteristics() const { return Characteristics; } getCOMDATSymbol()71 MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; } getSelection()72 int getSelection() const { return Selection; } 73 74 void setSelection(int Selection) const; 75 76 void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS, 77 const MCExpr *Subsection) const override; 78 bool UseCodeAlign() const override; 79 bool isVirtualSection() const override; 80 getOrAssignWinCFISectionID(unsigned * NextID)81 unsigned getOrAssignWinCFISectionID(unsigned *NextID) const { 82 if (WinCFISectionID == ~0U) 83 WinCFISectionID = (*NextID)++; 84 return WinCFISectionID; 85 } 86 classof(const MCSection * S)87 static bool classof(const MCSection *S) { return S->getVariant() == SV_COFF; } 88 }; 89 90 } // end namespace llvm 91 92 #endif 93