LLVM  9.0.0svn
MCSectionMachO.h
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1 //===- MCSectionMachO.h - MachO Machine Code Sections -----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file declares the MCSectionMachO class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_MC_MCSECTIONMACHO_H
14 #define LLVM_MC_MCSECTIONMACHO_H
15 
16 #include "llvm/ADT/StringRef.h"
18 #include "llvm/MC/MCSection.h"
19 
20 namespace llvm {
21 
22 /// This represents a section on a Mach-O system (used by Mac OS X). On a Mac
23 /// system, these are also described in /usr/include/mach-o/loader.h.
24 class MCSectionMachO final : public MCSection {
25  char SegmentName[16]; // Not necessarily null terminated!
26  char SectionName[16]; // Not necessarily null terminated!
27 
28  /// This is the SECTION_TYPE and SECTION_ATTRIBUTES field of a section, drawn
29  /// from the enums below.
30  unsigned TypeAndAttributes;
31 
32  /// The 'reserved2' field of a section, used to represent the size of stubs,
33  /// for example.
34  unsigned Reserved2;
35 
36  MCSectionMachO(StringRef Segment, StringRef Section, unsigned TAA,
37  unsigned reserved2, SectionKind K, MCSymbol *Begin);
38  friend class MCContext;
39 public:
40 
42  // SegmentName is not necessarily null terminated!
43  if (SegmentName[15])
44  return StringRef(SegmentName, 16);
45  return StringRef(SegmentName);
46  }
48  // SectionName is not necessarily null terminated!
49  if (SectionName[15])
50  return StringRef(SectionName, 16);
51  return StringRef(SectionName);
52  }
53 
54  unsigned getTypeAndAttributes() const { return TypeAndAttributes; }
55  unsigned getStubSize() const { return Reserved2; }
56 
58  return static_cast<MachO::SectionType>(TypeAndAttributes &
60  }
61  bool hasAttribute(unsigned Value) const {
62  return (TypeAndAttributes & Value) != 0;
63  }
64 
65  /// Parse the section specifier indicated by "Spec". This is a string that can
66  /// appear after a .section directive in a mach-o flavored .s file. If
67  /// successful, this fills in the specified Out parameters and returns an
68  /// empty string. When an invalid section specifier is present, this returns
69  /// a string indicating the problem. If no TAA was parsed, TAA is not altered,
70  /// and TAAWasSet becomes false.
71  static std::string ParseSectionSpecifier(StringRef Spec, // In.
72  StringRef &Segment, // Out.
73  StringRef &Section, // Out.
74  unsigned &TAA, // Out.
75  bool &TAAParsed, // Out.
76  unsigned &StubSize); // Out.
77 
78  void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
79  raw_ostream &OS,
80  const MCExpr *Subsection) const override;
81  bool UseCodeAlign() const override;
82  bool isVirtualSection() const override;
83 
84  static bool classof(const MCSection *S) {
85  return S->getVariant() == SV_MachO;
86  }
87 };
88 
89 } // end namespace llvm
90 
91 #endif
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:38
bool hasAttribute(unsigned Value) const
This represents a section on a Mach-O system (used by Mac OS X).
This class represents lattice values for constants.
Definition: AllocatorList.h:23
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
static bool classof(const MCSection *S)
unsigned getTypeAndAttributes() const
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
StringRef getSectionName() const
Context object for machine code objects.
Definition: MCContext.h:62
unsigned getStubSize() const
StringRef getSegmentName() const
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
static std::string ParseSectionSpecifier(StringRef Spec, StringRef &Segment, StringRef &Section, unsigned &TAA, bool &TAAParsed, unsigned &StubSize)
Parse the section specifier indicated by "Spec".
SectionKind - This is a simple POD value that classifies the properties of a section.
Definition: SectionKind.h:22
SectionVariant getVariant() const
Definition: MCSection.h:107
bool UseCodeAlign() const override
Return true if a .align directive should use "optimized nops" to fill instead of 0s.
MachO::SectionType getType() const
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:43
bool isVirtualSection() const override
Check whether this section is "virtual", that is has no actual object file contents.
LLVM Value Representation.
Definition: Value.h:72
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
SectionType
These are the section type and attributes fields.
Definition: MachO.h:114
void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T, raw_ostream &OS, const MCExpr *Subsection) const override