MCSectionCOFF.h revision 6e5ce287b0e53c264af0ba37169ad964e19b5bb7 
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/MC/MCSection.h"
18
19namespace llvm {
20
21/// MCSectionCOFF - This represents a section on Windows
22  class MCSectionCOFF : public MCSection {
23    // The memory for this string is stored in the same MCContext as *this.
24    StringRef SectionName;
25
26    /// Characteristics - This is the Characteristics field of a section,
27    //  drawn from the enums below.
28    unsigned Characteristics;
29
30    /// Selection - This is the Selection field for the section symbol, if
31    /// it is a COMDAT section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0
32    int Selection;
33
34  private:
35    friend class MCContext;
36    MCSectionCOFF(StringRef Section, unsigned Characteristics,
37                  int Selection, SectionKind K)
38      : MCSection(K), SectionName(Section), Characteristics(Characteristics),
39        Selection (Selection) {
40      assert ((Characteristics & 0x00F00000) == 0 &&
41        "alignment must not be set upon section creation");
42    }
43    ~MCSectionCOFF();
44
45  public:
46    /// ShouldOmitSectionDirective - Decides whether a '.section' directive
47    /// should be printed before the section name
48    bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
49
50    //FIXME: all COFF enumerations/flags should be standardized into one place...
51    // Target/X86COFF.h doesn't seem right as COFF can be used for other targets,
52    // MC/WinCOFF.h maybe right as it isn't target or entity specific, and it is
53    //   pretty low on the dependancy graph (is there any need to support non
54    //   windows COFF?)
55    // here is good for section stuff, but others should go elsewhere
56
57    /// Valid section flags.
58    enum {
59      IMAGE_SCN_TYPE_NO_PAD                     = 0x00000008,
60      IMAGE_SCN_CNT_CODE                        = 0x00000020,
61      IMAGE_SCN_CNT_INITIALIZED_DATA            = 0x00000040,
62      IMAGE_SCN_CNT_UNINITIALIZED_DATA          = 0x00000080,
63      IMAGE_SCN_LNK_OTHER                       = 0x00000100,
64      IMAGE_SCN_LNK_INFO                        = 0x00000200,
65      IMAGE_SCN_LNK_REMOVE                      = 0x00000800,
66      IMAGE_SCN_LNK_COMDAT                      = 0x00001000,
67      IMAGE_SCN_MEM_FARDATA                     = 0x00008000,
68      IMAGE_SCN_MEM_PURGEABLE                   = 0x00020000,
69      IMAGE_SCN_MEM_16BIT                       = 0x00020000,
70      IMAGE_SCN_MEM_LOCKED                      = 0x00040000,
71      IMAGE_SCN_MEM_PRELOAD                     = 0x00080000,
72      /* these are handled elsewhere
73      IMAGE_SCN_ALIGN_1BYTES                    = 0x00100000,
74      IMAGE_SCN_ALIGN_2BYTES                    = 0x00200000,
75      IMAGE_SCN_ALIGN_4BYTES                    = 0x00300000,
76      IMAGE_SCN_ALIGN_8BYTES                    = 0x00400000,
77      IMAGE_SCN_ALIGN_16BYTES                   = 0x00500000,
78      IMAGE_SCN_ALIGN_32BYTES                   = 0x00600000,
79      IMAGE_SCN_ALIGN_64BYTES                   = 0x00700000,
80      */
81      IMAGE_SCN_LNK_NRELOC_OVFL                 = 0x01000000,
82      IMAGE_SCN_MEM_DISCARDABLE                 = 0x02000000,
83      IMAGE_SCN_MEM_NOT_CACHED                  = 0x04000000,
84      IMAGE_SCN_MEM_NOT_PAGED                   = 0x08000000,
85      IMAGE_SCN_MEM_SHARED                      = 0x10000000,
86      IMAGE_SCN_MEM_EXECUTE                     = 0x20000000,
87      IMAGE_SCN_MEM_READ                        = 0x40000000,
88      IMAGE_SCN_MEM_WRITE                       = 0x80000000
89    };
90
91    enum {
92      IMAGE_COMDAT_SELECT_NODUPLICATES = 1,
93      IMAGE_COMDAT_SELECT_ANY,
94      IMAGE_COMDAT_SELECT_SAME_SIZE,
95      IMAGE_COMDAT_SELECT_EXACT_MATCH,
96      IMAGE_COMDAT_SELECT_ASSOCIATIVE,
97      IMAGE_COMDAT_SELECT_LARGEST
98    };
99
100    StringRef getSectionName() const { return SectionName; }
101    unsigned getCharacteristics() const { return Characteristics; }
102    int getSelection () const { return Selection; }
103
104    virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
105                                      raw_ostream &OS) const;
106  };
107
108} // end namespace llvm
109
110#endif
111