include/llvm/MC/MCSectionXCOFF.h

   1 //===- MCSectionXCOFF.h - XCOFF 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 MCSectionXCOFF class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_MC_MCSECTIONXCOFF_H
  14 #define LLVM_MC_MCSECTIONXCOFF_H
  15
  16 #include "llvm/ADT/Twine.h"
  17 #include "llvm/BinaryFormat/XCOFF.h"
  18 #include "llvm/MC/MCSection.h"
  19
  20 namespace llvm {
  21
  22 class MCSymbol;
  23
  24 // This class represents an XCOFF `Control Section`, more commonly referred to
  25 // as a csect. A csect represents the smallest possible unit of data/code which
  26 // will be relocated as a single block. A csect can either be:
  27 // 1) Initialized: The Type will be XTY_SD, and the symbols inside the csect
  28 //    will have a label definition representing their offset within the csect.
  29 // 2) Uninitialized: The Type will be XTY_CM, it will contain a single symbol,
  30 //    and may not contain label definitions.
  31 // 3) An external reference providing a symbol table entry for a symbol
  32 //    contained in another XCOFF object file. External reference csects are not
  33 //    implemented yet.
  34 class MCSectionXCOFF final : public MCSection {
  35   friend class MCContext;
  36
  37   StringRef Name;
  38   XCOFF::StorageMappingClass MappingClass;
  39   XCOFF::SymbolType Type;
  40   XCOFF::StorageClass StorageClass;
  41
  42   MCSectionXCOFF(StringRef Section, XCOFF::StorageMappingClass SMC,
  43                  XCOFF::SymbolType ST, XCOFF::StorageClass SC, SectionKind K,
  44                  MCSymbol *Begin)
  45       : MCSection(SV_XCOFF, K, Begin), Name(Section), MappingClass(SMC),
  46         Type(ST), StorageClass(SC) {
  47     assert((ST == XCOFF::XTY_SD || ST == XCOFF::XTY_CM) &&
  48            "Invalid or unhandled type for csect.");
  49   }
  50
  51 public:
  52   ~MCSectionXCOFF();
  53
  54   static bool classof(const MCSection *S) {
  55     return S->getVariant() == SV_XCOFF;
  56   }
  57
  58   StringRef getSectionName() const { return Name; }
  59   XCOFF::StorageMappingClass getMappingClass() const { return MappingClass; }
  60   XCOFF::StorageClass getStorageClass() const { return StorageClass; }
  61   XCOFF::SymbolType getCSectType() const { return Type; }
  62
  63   void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
  64                             raw_ostream &OS,
  65                             const MCExpr *Subsection) const override;
  66   bool UseCodeAlign() const override;
  67   bool isVirtualSection() const override;
  68 };
  69
  70 } // end namespace llvm
  71
  72 #endif