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
21namespace 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      SV_LDContext
36    };
37
38  private:
39    MCSection(const MCSection&) LLVM_DELETED_FUNCTION;
40    void operator=(const MCSection&) LLVM_DELETED_FUNCTION;
41  protected:
42    MCSection(SectionVariant V, SectionKind K) : Variant(V), Kind(K) {}
43    SectionVariant Variant;
44    SectionKind Kind;
45  public:
46    virtual ~MCSection();
47
48    SectionKind getKind() const { return Kind; }
49
50    SectionVariant getVariant() const { return Variant; }
51
52    virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
53                                      raw_ostream &OS,
54                                      const MCExpr *Subsection) const = 0;
55
56    // Convenience routines to get label names for the beginning/end of a
57    // section.
58    virtual std::string getLabelBeginName() const = 0;
59    virtual std::string getLabelEndName() const = 0;
60
61    /// isBaseAddressKnownZero - Return true if we know that this section will
62    /// get a base address of zero.  In cases where we know that this is true we
63    /// can emit section offsets as direct references to avoid a subtraction
64    /// from the base of the section, saving a relocation.
65    virtual bool isBaseAddressKnownZero() const {
66      return false;
67    }
68
69    // UseCodeAlign - Return true if a .align directive should use
70    // "optimized nops" to fill instead of 0s.
71    virtual bool UseCodeAlign() const = 0;
72
73    /// isVirtualSection - Check whether this section is "virtual", that is
74    /// has no actual object file contents.
75    virtual bool isVirtualSection() const = 0;
76  };
77
78} // end namespace llvm
79
80#endif
81