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"
17 #include "llvm/BinaryFormat/MachO.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 
27   /// This is the SECTION_TYPE and SECTION_ATTRIBUTES field of a section, drawn
28   /// from the enums below.
29   unsigned TypeAndAttributes;
30 
31   /// The 'reserved2' field of a section, used to represent the size of stubs,
32   /// for example.
33   unsigned Reserved2;
34 
35   MCSectionMachO(StringRef Segment, StringRef Section, unsigned TAA,
36                  unsigned reserved2, SectionKind K, MCSymbol *Begin);
37   friend class MCContext;
38 public:
39 
getSegmentName()40   StringRef getSegmentName() const {
41     // SegmentName is not necessarily null terminated!
42     if (SegmentName[15])
43       return StringRef(SegmentName, 16);
44     return StringRef(SegmentName);
45   }
46 
getTypeAndAttributes()47   unsigned getTypeAndAttributes() const { return TypeAndAttributes; }
getStubSize()48   unsigned getStubSize() const { return Reserved2; }
49 
getType()50   MachO::SectionType getType() const {
51     return static_cast<MachO::SectionType>(TypeAndAttributes &
52                                            MachO::SECTION_TYPE);
53   }
hasAttribute(unsigned Value)54   bool hasAttribute(unsigned Value) const {
55     return (TypeAndAttributes & Value) != 0;
56   }
57 
58   /// Parse the section specifier indicated by "Spec". This is a string that can
59   /// appear after a .section directive in a mach-o flavored .s file.  If
60   /// successful, this fills in the specified Out parameters and returns an
61   /// empty string.  When an invalid section specifier is present, this returns
62   /// an Error indicating the problem. If no TAA was parsed, TAA is not altered,
63   /// and TAAWasSet becomes false.
64   static Error ParseSectionSpecifier(StringRef Spec,      // In.
65                                      StringRef &Segment,  // Out.
66                                      StringRef &Section,  // Out.
67                                      unsigned &TAA,       // Out.
68                                      bool &TAAParsed,     // Out.
69                                      unsigned &StubSize); // Out.
70 
71   void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
72                             raw_ostream &OS,
73                             const MCExpr *Subsection) const override;
74   bool UseCodeAlign() const override;
75   bool isVirtualSection() const override;
76 
classof(const MCSection * S)77   static bool classof(const MCSection *S) {
78     return S->getVariant() == SV_MachO;
79   }
80 };
81 
82 } // end namespace llvm
83 
84 #endif
85