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      1 //===- MCSection.h - 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 MCSection class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_MC_MCSECTION_H
     15 #define LLVM_MC_MCSECTION_H
     16 
     17 #include "llvm/ADT/StringRef.h"
     18 #include "llvm/MC/SectionKind.h"
     19 #include "llvm/Support/Compiler.h"
     20 
     21 namespace llvm {
     22 class MCAsmInfo;
     23 class MCContext;
     24 class MCExpr;
     25 class MCSymbol;
     26 class raw_ostream;
     27 
     28 /// Instances of this class represent a uniqued identifier for a section in the
     29 /// current translation unit.  The MCContext class uniques and creates these.
     30 class MCSection {
     31 public:
     32   enum SectionVariant { SV_COFF = 0, SV_ELF, SV_MachO };
     33 
     34 private:
     35   MCSection(const MCSection &) = delete;
     36   void operator=(const MCSection &) = delete;
     37 
     38   MCSymbol *Begin;
     39   mutable MCSymbol *End;
     40 
     41 protected:
     42   MCSection(SectionVariant V, SectionKind K, MCSymbol *Begin)
     43       : Begin(Begin), End(nullptr), Variant(V), Kind(K) {}
     44   SectionVariant Variant;
     45   SectionKind Kind;
     46 
     47 public:
     48   virtual ~MCSection();
     49 
     50   SectionKind getKind() const { return Kind; }
     51 
     52   SectionVariant getVariant() const { return Variant; }
     53 
     54   MCSymbol *getBeginSymbol() const { return Begin; }
     55   MCSymbol *getEndSymbol(MCContext &Ctx) const;
     56   bool hasEnded() const;
     57 
     58   virtual void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS,
     59                                     const MCExpr *Subsection) const = 0;
     60 
     61   /// Return true if a .align directive should use "optimized nops" to fill
     62   /// instead of 0s.
     63   virtual bool UseCodeAlign() const = 0;
     64 
     65   /// Check whether this section is "virtual", that is has no actual object
     66   /// file contents.
     67   virtual bool isVirtualSection() const = 0;
     68 };
     69 
     70 } // end namespace llvm
     71 
     72 #endif
     73