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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 MCExpr;
24   class raw_ostream;
25 
26   /// MCSection - Instances of this class represent a uniqued identifier for a
27   /// section in the current translation unit.  The MCContext class uniques and
28   /// creates these.
29   class MCSection {
30   public:
31     enum SectionVariant {
32       SV_COFF = 0,
33       SV_ELF,
34       SV_MachO
35     };
36 
37   private:
38     MCSection(const MCSection&) LLVM_DELETED_FUNCTION;
39     void operator=(const MCSection&) LLVM_DELETED_FUNCTION;
40   protected:
MCSection(SectionVariant V,SectionKind K)41     MCSection(SectionVariant V, SectionKind K) : Variant(V), Kind(K) {}
42     SectionVariant Variant;
43     SectionKind Kind;
44   public:
45     virtual ~MCSection();
46 
getKind()47     SectionKind getKind() const { return Kind; }
48 
getVariant()49     SectionVariant getVariant() const { return Variant; }
50 
51     virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
52                                       raw_ostream &OS,
53                                       const MCExpr *Subsection) const = 0;
54 
55     // Convenience routines to get label names for the beginning/end of a
56     // section.
57     virtual std::string getLabelBeginName() const = 0;
58     virtual std::string getLabelEndName() const = 0;
59 
60     /// isBaseAddressKnownZero - Return true if we know that this section will
61     /// get a base address of zero.  In cases where we know that this is true we
62     /// can emit section offsets as direct references to avoid a subtraction
63     /// from the base of the section, saving a relocation.
isBaseAddressKnownZero()64     virtual bool isBaseAddressKnownZero() const {
65       return false;
66     }
67 
68     // UseCodeAlign - Return true if a .align directive should use
69     // "optimized nops" to fill instead of 0s.
70     virtual bool UseCodeAlign() const = 0;
71 
72     /// isVirtualSection - Check whether this section is "virtual", that is
73     /// has no actual object file contents.
74     virtual bool isVirtualSection() const = 0;
75   };
76 
77 } // end namespace llvm
78 
79 #endif
80