1//===- MCSectionMachO.h - MachO 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 MCSectionMachO class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_MC_MCSECTIONMACHO_H
15#define LLVM_MC_MCSECTIONMACHO_H
16
17#include "llvm/MC/MCSection.h"
18#include "llvm/ADT/StringRef.h"
19
20namespace llvm {
21
22/// MCSectionMachO - This represents a section on a Mach-O system (used by
23/// Mac OS X).  On a Mac system, these are also described in
24/// /usr/include/mach-o/loader.h.
25class MCSectionMachO : public MCSection {
26  char SegmentName[16];  // Not necessarily null terminated!
27  char SectionName[16];  // Not necessarily null terminated!
28
29  /// TypeAndAttributes - This is the SECTION_TYPE and SECTION_ATTRIBUTES
30  /// field of a section, drawn from the enums below.
31  unsigned TypeAndAttributes;
32
33  /// Reserved2 - The 'reserved2' field of a section, used to represent the
34  /// size of stubs, for example.
35  unsigned Reserved2;
36
37  MCSectionMachO(StringRef Segment, StringRef Section,
38                 unsigned TAA, unsigned reserved2, SectionKind K);
39  friend class MCContext;
40public:
41
42  /// These are the section type and attributes fields.  A MachO section can
43  /// have only one Type, but can have any of the attributes specified.
44  enum {
45    // TypeAndAttributes bitmasks.
46    SECTION_TYPE       = 0x000000FFU,
47    SECTION_ATTRIBUTES = 0xFFFFFF00U,
48
49    // Valid section types.
50
51    /// S_REGULAR - Regular section.
52    S_REGULAR                    = 0x00U,
53    /// S_ZEROFILL - Zero fill on demand section.
54    S_ZEROFILL                   = 0x01U,
55    /// S_CSTRING_LITERALS - Section with literal C strings.
56    S_CSTRING_LITERALS           = 0x02U,
57    /// S_4BYTE_LITERALS - Section with 4 byte literals.
58    S_4BYTE_LITERALS             = 0x03U,
59    /// S_8BYTE_LITERALS - Section with 8 byte literals.
60    S_8BYTE_LITERALS             = 0x04U,
61    /// S_LITERAL_POINTERS - Section with pointers to literals.
62    S_LITERAL_POINTERS           = 0x05U,
63    /// S_NON_LAZY_SYMBOL_POINTERS - Section with non-lazy symbol pointers.
64    S_NON_LAZY_SYMBOL_POINTERS   = 0x06U,
65    /// S_LAZY_SYMBOL_POINTERS - Section with lazy symbol pointers.
66    S_LAZY_SYMBOL_POINTERS       = 0x07U,
67    /// S_SYMBOL_STUBS - Section with symbol stubs, byte size of stub in
68    /// the Reserved2 field.
69    S_SYMBOL_STUBS               = 0x08U,
70    /// S_MOD_INIT_FUNC_POINTERS - Section with only function pointers for
71    /// initialization.
72    S_MOD_INIT_FUNC_POINTERS     = 0x09U,
73    /// S_MOD_TERM_FUNC_POINTERS - Section with only function pointers for
74    /// termination.
75    S_MOD_TERM_FUNC_POINTERS     = 0x0AU,
76    /// S_COALESCED - Section contains symbols that are to be coalesced.
77    S_COALESCED                  = 0x0BU,
78    /// S_GB_ZEROFILL - Zero fill on demand section (that can be larger than 4
79    /// gigabytes).
80    S_GB_ZEROFILL                = 0x0CU,
81    /// S_INTERPOSING - Section with only pairs of function pointers for
82    /// interposing.
83    S_INTERPOSING                = 0x0DU,
84    /// S_16BYTE_LITERALS - Section with only 16 byte literals.
85    S_16BYTE_LITERALS            = 0x0EU,
86    /// S_DTRACE_DOF - Section contains DTrace Object Format.
87    S_DTRACE_DOF                 = 0x0FU,
88    /// S_LAZY_DYLIB_SYMBOL_POINTERS - Section with lazy symbol pointers to
89    /// lazy loaded dylibs.
90    S_LAZY_DYLIB_SYMBOL_POINTERS = 0x10U,
91    /// S_THREAD_LOCAL_REGULAR - Section with ....
92    S_THREAD_LOCAL_REGULAR = 0x11U,
93    /// S_THREAD_LOCAL_ZEROFILL - Thread local zerofill section.
94    S_THREAD_LOCAL_ZEROFILL = 0x12U,
95    /// S_THREAD_LOCAL_VARIABLES - Section with thread local variable structure
96    /// data.
97    S_THREAD_LOCAL_VARIABLES = 0x13U,
98    /// S_THREAD_LOCAL_VARIABLE_POINTERS - Section with ....
99    S_THREAD_LOCAL_VARIABLE_POINTERS = 0x14U,
100    /// S_THREAD_LOCAL_INIT_FUNCTION_POINTERS - Section with thread local
101    /// variable initialization pointers to functions.
102    S_THREAD_LOCAL_INIT_FUNCTION_POINTERS = 0x15U,
103
104    LAST_KNOWN_SECTION_TYPE = S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
105
106
107    // Valid section attributes.
108
109    /// S_ATTR_PURE_INSTRUCTIONS - Section contains only true machine
110    /// instructions.
111    S_ATTR_PURE_INSTRUCTIONS   = 1U << 31,
112    /// S_ATTR_NO_TOC - Section contains coalesced symbols that are not to be
113    /// in a ranlib table of contents.
114    S_ATTR_NO_TOC              = 1U << 30,
115    /// S_ATTR_STRIP_STATIC_SYMS - Ok to strip static symbols in this section
116    /// in files with the MY_DYLDLINK flag.
117    S_ATTR_STRIP_STATIC_SYMS   = 1U << 29,
118    /// S_ATTR_NO_DEAD_STRIP - No dead stripping.
119    S_ATTR_NO_DEAD_STRIP       = 1U << 28,
120    /// S_ATTR_LIVE_SUPPORT - Blocks are live if they reference live blocks.
121    S_ATTR_LIVE_SUPPORT        = 1U << 27,
122    /// S_ATTR_SELF_MODIFYING_CODE - Used with i386 code stubs written on by
123    /// dyld.
124    S_ATTR_SELF_MODIFYING_CODE = 1U << 26,
125    /// S_ATTR_DEBUG - A debug section.
126    S_ATTR_DEBUG               = 1U << 25,
127    /// S_ATTR_SOME_INSTRUCTIONS - Section contains some machine instructions.
128    S_ATTR_SOME_INSTRUCTIONS   = 1U << 10,
129    /// S_ATTR_EXT_RELOC - Section has external relocation entries.
130    S_ATTR_EXT_RELOC           = 1U << 9,
131    /// S_ATTR_LOC_RELOC - Section has local relocation entries.
132    S_ATTR_LOC_RELOC           = 1U << 8
133  };
134
135  StringRef getSegmentName() const {
136    // SegmentName is not necessarily null terminated!
137    if (SegmentName[15])
138      return StringRef(SegmentName, 16);
139    return StringRef(SegmentName);
140  }
141  StringRef getSectionName() const {
142    // SectionName is not necessarily null terminated!
143    if (SectionName[15])
144      return StringRef(SectionName, 16);
145    return StringRef(SectionName);
146  }
147
148  unsigned getTypeAndAttributes() const { return TypeAndAttributes; }
149  unsigned getStubSize() const { return Reserved2; }
150
151  unsigned getType() const { return TypeAndAttributes & SECTION_TYPE; }
152  bool hasAttribute(unsigned Value) const {
153    return (TypeAndAttributes & Value) != 0;
154  }
155
156  /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec".
157  /// This is a string that can appear after a .section directive in a mach-o
158  /// flavored .s file.  If successful, this fills in the specified Out
159  /// parameters and returns an empty string.  When an invalid section
160  /// specifier is present, this returns a string indicating the problem.
161  /// If no TAA was parsed, TAA is not altered, and TAAWasSet becomes false.
162  static std::string ParseSectionSpecifier(StringRef Spec,       // In.
163                                           StringRef &Segment,   // Out.
164                                           StringRef &Section,   // Out.
165                                           unsigned  &TAA,       // Out.
166                                           bool      &TAAParsed, // Out.
167                                           unsigned  &StubSize); // Out.
168
169  virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
170                                    raw_ostream &OS) const;
171  virtual bool UseCodeAlign() const;
172  virtual bool isVirtualSection() const;
173
174  static bool classof(const MCSection *S) {
175    return S->getVariant() == SV_MachO;
176  }
177  static bool classof(const MCSectionMachO *) { return true; }
178};
179
180} // end namespace llvm
181
182#endif
183