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      1 //===-- llvm/MC/MCObjectFileInfo.h - Object File Info -----------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file describes common object file formats.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_MC_MCBJECTFILEINFO_H
     15 #define LLVM_MC_MCBJECTFILEINFO_H
     16 
     17 #include "llvm/Support/CodeGen.h"
     18 
     19 namespace llvm {
     20   class MCContext;
     21   class MCSection;
     22   class StringRef;
     23   class Triple;
     24 
     25 class MCObjectFileInfo {
     26 protected:
     27   /// CommDirectiveSupportsAlignment - True if .comm supports alignment.  This
     28   /// is a hack for as long as we support 10.4 Tiger, whose assembler doesn't
     29   /// support alignment on comm.
     30   bool CommDirectiveSupportsAlignment;
     31 
     32   /// SupportsWeakEmptyEHFrame - True if target object file supports a
     33   /// weak_definition of constant 0 for an omitted EH frame.
     34   bool SupportsWeakOmittedEHFrame;
     35 
     36   /// IsFunctionEHFrameSymbolPrivate - This flag is set to true if the
     37   /// "EH_frame" symbol for EH information should be an assembler temporary (aka
     38   /// private linkage, aka an L or .L label) or false if it should be a normal
     39   /// non-.globl label.  This defaults to true.
     40   bool IsFunctionEHFrameSymbolPrivate;
     41 
     42   /// PersonalityEncoding, LSDAEncoding, FDEEncoding, TTypeEncoding - Some
     43   /// encoding values for EH.
     44   unsigned PersonalityEncoding;
     45   unsigned LSDAEncoding;
     46   unsigned FDEEncoding;
     47   unsigned FDECFIEncoding;
     48   unsigned TTypeEncoding;
     49   // Section flags for eh_frame
     50   unsigned EHSectionType;
     51   unsigned EHSectionFlags;
     52 
     53   /// TextSection - Section directive for standard text.
     54   ///
     55   const MCSection *TextSection;
     56 
     57   /// DataSection - Section directive for standard data.
     58   ///
     59   const MCSection *DataSection;
     60 
     61   /// BSSSection - Section that is default initialized to zero.
     62   const MCSection *BSSSection;
     63 
     64   /// ReadOnlySection - Section that is readonly and can contain arbitrary
     65   /// initialized data.  Targets are not required to have a readonly section.
     66   /// If they don't, various bits of code will fall back to using the data
     67   /// section for constants.
     68   const MCSection *ReadOnlySection;
     69 
     70   /// StaticCtorSection - This section contains the static constructor pointer
     71   /// list.
     72   const MCSection *StaticCtorSection;
     73 
     74   /// StaticDtorSection - This section contains the static destructor pointer
     75   /// list.
     76   const MCSection *StaticDtorSection;
     77 
     78   /// LSDASection - If exception handling is supported by the target, this is
     79   /// the section the Language Specific Data Area information is emitted to.
     80   const MCSection *LSDASection;
     81 
     82   /// CompactUnwindSection - If exception handling is supported by the target
     83   /// and the target can support a compact representation of the CIE and FDE,
     84   /// this is the section to emit them into.
     85   const MCSection *CompactUnwindSection;
     86 
     87   /// DwarfAccelNamesSection, DwarfAccelObjCSection
     88   /// If we use the DWARF accelerated hash tables then we want toe emit these
     89   /// sections.
     90   const MCSection *DwarfAccelNamesSection;
     91   const MCSection *DwarfAccelObjCSection;
     92   const MCSection *DwarfAccelNamespaceSection;
     93   const MCSection *DwarfAccelTypesSection;
     94 
     95   // Dwarf sections for debug info.  If a target supports debug info, these must
     96   // be set.
     97   const MCSection *DwarfAbbrevSection;
     98   const MCSection *DwarfInfoSection;
     99   const MCSection *DwarfLineSection;
    100   const MCSection *DwarfFrameSection;
    101   const MCSection *DwarfPubTypesSection;
    102   const MCSection *DwarfDebugInlineSection;
    103   const MCSection *DwarfStrSection;
    104   const MCSection *DwarfLocSection;
    105   const MCSection *DwarfARangesSection;
    106   const MCSection *DwarfRangesSection;
    107   const MCSection *DwarfMacroInfoSection;
    108 
    109   // Extra TLS Variable Data section.  If the target needs to put additional
    110   // information for a TLS variable, it'll go here.
    111   const MCSection *TLSExtraDataSection;
    112 
    113   /// TLSDataSection - Section directive for Thread Local data.
    114   /// ELF, MachO and COFF.
    115   const MCSection *TLSDataSection;        // Defaults to ".tdata".
    116 
    117   /// TLSBSSSection - Section directive for Thread Local uninitialized data.
    118   /// Null if this target doesn't support a BSS section.
    119   /// ELF and MachO only.
    120   const MCSection *TLSBSSSection;         // Defaults to ".tbss".
    121 
    122 
    123   /// EHFrameSection - EH frame section. It is initialized on demand so it
    124   /// can be overwritten (with uniquing).
    125   const MCSection *EHFrameSection;
    126 
    127   /// ELF specific sections.
    128   ///
    129   const MCSection *DataRelSection;
    130   const MCSection *DataRelLocalSection;
    131   const MCSection *DataRelROSection;
    132   const MCSection *DataRelROLocalSection;
    133   const MCSection *MergeableConst4Section;
    134   const MCSection *MergeableConst8Section;
    135   const MCSection *MergeableConst16Section;
    136 
    137   /// MachO specific sections.
    138   ///
    139 
    140   /// TLSTLVSection - Section for thread local structure information.
    141   /// Contains the source code name of the variable, visibility and a pointer
    142   /// to the initial value (.tdata or .tbss).
    143   const MCSection *TLSTLVSection;         // Defaults to ".tlv".
    144 
    145   /// TLSThreadInitSection - Section for thread local data initialization
    146   /// functions.
    147   const MCSection *TLSThreadInitSection;  // Defaults to ".thread_init_func".
    148 
    149   const MCSection *CStringSection;
    150   const MCSection *UStringSection;
    151   const MCSection *TextCoalSection;
    152   const MCSection *ConstTextCoalSection;
    153   const MCSection *ConstDataSection;
    154   const MCSection *DataCoalSection;
    155   const MCSection *DataCommonSection;
    156   const MCSection *DataBSSSection;
    157   const MCSection *FourByteConstantSection;
    158   const MCSection *EightByteConstantSection;
    159   const MCSection *SixteenByteConstantSection;
    160   const MCSection *LazySymbolPointerSection;
    161   const MCSection *NonLazySymbolPointerSection;
    162 
    163   /// COFF specific sections.
    164   ///
    165   const MCSection *DrectveSection;
    166   const MCSection *PDataSection;
    167   const MCSection *XDataSection;
    168 
    169 public:
    170   void InitMCObjectFileInfo(StringRef TT, Reloc::Model RM, CodeModel::Model CM,
    171                             MCContext &ctx);
    172 
    173   bool isFunctionEHFrameSymbolPrivate() const {
    174     return IsFunctionEHFrameSymbolPrivate;
    175   }
    176   bool getSupportsWeakOmittedEHFrame() const {
    177     return SupportsWeakOmittedEHFrame;
    178   }
    179   bool getCommDirectiveSupportsAlignment() const {
    180     return CommDirectiveSupportsAlignment;
    181   }
    182 
    183   unsigned getPersonalityEncoding() const { return PersonalityEncoding; }
    184   unsigned getLSDAEncoding() const { return LSDAEncoding; }
    185   unsigned getFDEEncoding(bool CFI) const {
    186     return CFI ? FDECFIEncoding : FDEEncoding;
    187   }
    188   unsigned getTTypeEncoding() const { return TTypeEncoding; }
    189 
    190   const MCSection *getTextSection() const { return TextSection; }
    191   const MCSection *getDataSection() const { return DataSection; }
    192   const MCSection *getBSSSection() const { return BSSSection; }
    193   const MCSection *getLSDASection() const { return LSDASection; }
    194   const MCSection *getCompactUnwindSection() const{
    195     return CompactUnwindSection;
    196   }
    197   const MCSection *getDwarfAccelNamesSection() const {
    198     return DwarfAccelNamesSection;
    199   }
    200   const MCSection *getDwarfAccelObjCSection() const {
    201     return DwarfAccelObjCSection;
    202   }
    203   const MCSection *getDwarfAccelNamespaceSection() const {
    204     return DwarfAccelNamespaceSection;
    205   }
    206   const MCSection *getDwarfAccelTypesSection() const {
    207     return DwarfAccelTypesSection;
    208   }
    209   const MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
    210   const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
    211   const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
    212   const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
    213   const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
    214   const MCSection *getDwarfDebugInlineSection() const {
    215     return DwarfDebugInlineSection;
    216   }
    217   const MCSection *getDwarfStrSection() const { return DwarfStrSection; }
    218   const MCSection *getDwarfLocSection() const { return DwarfLocSection; }
    219   const MCSection *getDwarfARangesSection() const { return DwarfARangesSection;}
    220   const MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
    221   const MCSection *getDwarfMacroInfoSection() const {
    222     return DwarfMacroInfoSection;
    223   }
    224   const MCSection *getTLSExtraDataSection() const {
    225     return TLSExtraDataSection;
    226   }
    227   const MCSection *getTLSDataSection() const { return TLSDataSection; }
    228   const MCSection *getTLSBSSSection() const { return TLSBSSSection; }
    229 
    230   /// ELF specific sections.
    231   ///
    232   const MCSection *getDataRelSection() const { return DataRelSection; }
    233   const MCSection *getDataRelLocalSection() const {
    234     return DataRelLocalSection;
    235   }
    236   const MCSection *getDataRelROSection() const { return DataRelROSection; }
    237   const MCSection *getDataRelROLocalSection() const {
    238     return DataRelROLocalSection;
    239   }
    240   const MCSection *getMergeableConst4Section() const {
    241     return MergeableConst4Section;
    242   }
    243   const MCSection *getMergeableConst8Section() const {
    244     return MergeableConst8Section;
    245   }
    246   const MCSection *getMergeableConst16Section() const {
    247     return MergeableConst16Section;
    248   }
    249 
    250   /// MachO specific sections.
    251   ///
    252   const MCSection *getTLSTLVSection() const { return TLSTLVSection; }
    253   const MCSection *getTLSThreadInitSection() const {
    254     return TLSThreadInitSection;
    255   }
    256   const MCSection *getCStringSection() const { return CStringSection; }
    257   const MCSection *getUStringSection() const { return UStringSection; }
    258   const MCSection *getTextCoalSection() const { return TextCoalSection; }
    259   const MCSection *getConstTextCoalSection() const {
    260     return ConstTextCoalSection;
    261   }
    262   const MCSection *getConstDataSection() const { return ConstDataSection; }
    263   const MCSection *getDataCoalSection() const { return DataCoalSection; }
    264   const MCSection *getDataCommonSection() const { return DataCommonSection; }
    265   const MCSection *getDataBSSSection() const { return DataBSSSection; }
    266   const MCSection *getFourByteConstantSection() const {
    267     return FourByteConstantSection;
    268   }
    269   const MCSection *getEightByteConstantSection() const {
    270     return EightByteConstantSection;
    271   }
    272   const MCSection *getSixteenByteConstantSection() const {
    273     return SixteenByteConstantSection;
    274   }
    275   const MCSection *getLazySymbolPointerSection() const {
    276     return LazySymbolPointerSection;
    277   }
    278   const MCSection *getNonLazySymbolPointerSection() const {
    279     return NonLazySymbolPointerSection;
    280   }
    281 
    282   /// COFF specific sections.
    283   ///
    284   const MCSection *getDrectveSection() const { return DrectveSection; }
    285   const MCSection *getPDataSection() const { return PDataSection; }
    286   const MCSection *getXDataSection() const { return XDataSection; }
    287 
    288   const MCSection *getEHFrameSection() {
    289     if (!EHFrameSection)
    290       InitEHFrameSection();
    291     return EHFrameSection;
    292   }
    293 
    294 private:
    295   enum Environment { IsMachO, IsELF, IsCOFF };
    296   Environment Env;
    297   Reloc::Model RelocM;
    298   CodeModel::Model CMModel;
    299   MCContext *Ctx;
    300 
    301   void InitMachOMCObjectFileInfo(Triple T);
    302   void InitELFMCObjectFileInfo(Triple T);
    303   void InitCOFFMCObjectFileInfo(Triple T);
    304 
    305   /// InitEHFrameSection - Initialize EHFrameSection on demand.
    306   ///
    307   void InitEHFrameSection();
    308 };
    309 
    310 } // end namespace llvm
    311 
    312 #endif
    313