include/llvm/MC/MCSectionMachO.h

   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   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
  41   StringRef getSegmentName() const {
  42     // SegmentName is not necessarily null terminated!
  43     if (SegmentName[15])
  44       return StringRef(SegmentName, 16);
  45     return StringRef(SegmentName);
  46   }
  47   StringRef getSectionName() const {
  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
  57   MachO::SectionType getType() const {
  58     return static_cast<MachO::SectionType>(TypeAndAttributes &
  59                                            MachO::SECTION_TYPE);
  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