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      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 #include "llvm/Support/COFF.h"
     20 
     21 namespace llvm {
     22 class MCSymbol;
     23 
     24 /// MCSectionCOFF - This represents a section on Windows
     25   class MCSectionCOFF : public MCSection {
     26     // The memory for this string is stored in the same MCContext as *this.
     27     StringRef SectionName;
     28 
     29     // FIXME: The following fields should not be mutable, but are for now so
     30     // the asm parser can honor the .linkonce directive.
     31 
     32     /// Characteristics - This is the Characteristics field of a section,
     33     /// drawn from the enums below.
     34     mutable unsigned Characteristics;
     35 
     36     /// The COMDAT symbol of this section. Only valid if this is a COMDAT
     37     /// section. Two COMDAT sections are merged if they have the same
     38     /// COMDAT symbol.
     39     const MCSymbol *COMDATSymbol;
     40 
     41     /// Selection - This is the Selection field for the section symbol, if
     42     /// it is a COMDAT section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0
     43     mutable int Selection;
     44 
     45   private:
     46     friend class MCContext;
     47     MCSectionCOFF(StringRef Section, unsigned Characteristics,
     48                   const MCSymbol *COMDATSymbol, int Selection, SectionKind K)
     49         : MCSection(SV_COFF, K), SectionName(Section),
     50           Characteristics(Characteristics), COMDATSymbol(COMDATSymbol),
     51           Selection(Selection) {
     52       assert ((Characteristics & 0x00F00000) == 0 &&
     53         "alignment must not be set upon section creation");
     54     }
     55     ~MCSectionCOFF();
     56 
     57   public:
     58     /// ShouldOmitSectionDirective - Decides whether a '.section' directive
     59     /// should be printed before the section name
     60     bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
     61 
     62     StringRef getSectionName() const { return SectionName; }
     63     std::string getLabelBeginName() const override {
     64       return SectionName.str() + "_begin";
     65     }
     66     std::string getLabelEndName() const override {
     67       return SectionName.str() + "_end";
     68     }
     69     unsigned getCharacteristics() const { return Characteristics; }
     70     const MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; }
     71     int getSelection() const { return Selection; }
     72 
     73     void setSelection(int Selection) const;
     74 
     75     void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS,
     76                               const MCExpr *Subsection) const override;
     77     bool UseCodeAlign() const override;
     78     bool isVirtualSection() const override;
     79 
     80     static bool classof(const MCSection *S) {
     81       return S->getVariant() == SV_COFF;
     82     }
     83   };
     84 
     85 } // end namespace llvm
     86 
     87 #endif
     88