Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

Rev

Blame | Last modification | View Log | Download | RSS feed

  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/BinaryFormat/XCOFF.h"
  17. #include "llvm/MC/MCSection.h"
  18. #include "llvm/MC/MCSymbolXCOFF.h"
  19.  
  20. namespace llvm {
  21.  
  22. // This class represents an XCOFF `Control Section`, more commonly referred to
  23. // as a csect. A csect represents the smallest possible unit of data/code which
  24. // will be relocated as a single block. A csect can either be:
  25. // 1) Initialized: The Type will be XTY_SD, and the symbols inside the csect
  26. //    will have a label definition representing their offset within the csect.
  27. // 2) Uninitialized: The Type will be XTY_CM, it will contain a single symbol,
  28. //    and may not contain label definitions.
  29. // 3) An external reference providing a symbol table entry for a symbol
  30. //    contained in another XCOFF object file. External reference csects are not
  31. //    implemented yet.
  32. class MCSectionXCOFF final : public MCSection {
  33.   friend class MCContext;
  34.  
  35.   std::optional<XCOFF::CsectProperties> CsectProp;
  36.   MCSymbolXCOFF *const QualName;
  37.   StringRef SymbolTableName;
  38.   std::optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSubtypeFlags;
  39.   bool MultiSymbolsAllowed;
  40.   static constexpr unsigned DefaultAlignVal = 4;
  41.   static constexpr unsigned DefaultTextAlignVal = 32;
  42.  
  43.   MCSectionXCOFF(StringRef Name, XCOFF::StorageMappingClass SMC,
  44.                  XCOFF::SymbolType ST, SectionKind K, MCSymbolXCOFF *QualName,
  45.                  MCSymbol *Begin, StringRef SymbolTableName,
  46.                  bool MultiSymbolsAllowed)
  47.       : MCSection(SV_XCOFF, Name, K, Begin),
  48.         CsectProp(XCOFF::CsectProperties(SMC, ST)), QualName(QualName),
  49.         SymbolTableName(SymbolTableName), DwarfSubtypeFlags(std::nullopt),
  50.         MultiSymbolsAllowed(MultiSymbolsAllowed) {
  51.     assert(
  52.         (ST == XCOFF::XTY_SD || ST == XCOFF::XTY_CM || ST == XCOFF::XTY_ER) &&
  53.         "Invalid or unhandled type for csect.");
  54.     assert(QualName != nullptr && "QualName is needed.");
  55.     if (SMC == XCOFF::XMC_UL)
  56.       assert((ST == XCOFF::XTY_CM || ST == XCOFF::XTY_ER) &&
  57.              "Invalid csect type for storage mapping class XCOFF::XMC_UL");
  58.  
  59.     QualName->setRepresentedCsect(this);
  60.     QualName->setStorageClass(XCOFF::C_HIDEXT);
  61.     if (ST != XCOFF::XTY_ER) {
  62.       // For a csect for program code, set the alignment to 32 bytes by default.
  63.       // For other csects, set the alignment to 4 bytes by default.
  64.       if (SMC == XCOFF::XMC_PR)
  65.         setAlignment(Align(DefaultTextAlignVal));
  66.       else
  67.         setAlignment(Align(DefaultAlignVal));
  68.     }
  69.   }
  70.  
  71.   MCSectionXCOFF(StringRef Name, SectionKind K, MCSymbolXCOFF *QualName,
  72.                  XCOFF::DwarfSectionSubtypeFlags DwarfSubtypeFlags,
  73.                  MCSymbol *Begin, StringRef SymbolTableName,
  74.                  bool MultiSymbolsAllowed)
  75.       : MCSection(SV_XCOFF, Name, K, Begin), QualName(QualName),
  76.         SymbolTableName(SymbolTableName), DwarfSubtypeFlags(DwarfSubtypeFlags),
  77.         MultiSymbolsAllowed(MultiSymbolsAllowed) {
  78.     assert(QualName != nullptr && "QualName is needed.");
  79.  
  80.     // FIXME: use a more meaningful name for non csect sections.
  81.     QualName->setRepresentedCsect(this);
  82.  
  83.     // Use default text alignment as the alignment for DWARF sections.
  84.     setAlignment(Align(DefaultTextAlignVal));
  85.   }
  86.  
  87.   void printCsectDirective(raw_ostream &OS) const;
  88.  
  89. public:
  90.   ~MCSectionXCOFF();
  91.  
  92.   static bool classof(const MCSection *S) {
  93.     return S->getVariant() == SV_XCOFF;
  94.   }
  95.  
  96.   XCOFF::StorageMappingClass getMappingClass() const {
  97.     assert(isCsect() && "Only csect section has mapping class property!");
  98.     return CsectProp->MappingClass;
  99.   }
  100.   XCOFF::StorageClass getStorageClass() const {
  101.     return QualName->getStorageClass();
  102.   }
  103.   XCOFF::VisibilityType getVisibilityType() const {
  104.     return QualName->getVisibilityType();
  105.   }
  106.   XCOFF::SymbolType getCSectType() const {
  107.     assert(isCsect() && "Only csect section has symbol type property!");
  108.     return CsectProp->Type;
  109.   }
  110.   MCSymbolXCOFF *getQualNameSymbol() const { return QualName; }
  111.  
  112.   void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
  113.                             raw_ostream &OS,
  114.                             const MCExpr *Subsection) const override;
  115.   bool useCodeAlign() const override;
  116.   bool isVirtualSection() const override;
  117.   StringRef getSymbolTableName() const { return SymbolTableName; }
  118.   bool isMultiSymbolsAllowed() const { return MultiSymbolsAllowed; }
  119.   bool isCsect() const { return CsectProp.has_value(); }
  120.   bool isDwarfSect() const { return DwarfSubtypeFlags.has_value(); }
  121.   std::optional<XCOFF::DwarfSectionSubtypeFlags> getDwarfSubtypeFlags() const {
  122.     return DwarfSubtypeFlags;
  123.   }
  124.   std::optional<XCOFF::CsectProperties> getCsectProp() const {
  125.     return CsectProp;
  126.   }
  127. };
  128.  
  129. } // end namespace llvm
  130.  
  131. #endif
  132.