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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 
     50   /// Section flags for eh_frame
     51   unsigned EHSectionType;
     52   unsigned EHSectionFlags;
     53 
     54   /// CompactUnwindDwarfEHFrameOnly - Compact unwind encoding indicating that we
     55   /// should emit only an EH frame.
     56   unsigned CompactUnwindDwarfEHFrameOnly;
     57 
     58   /// TextSection - Section directive for standard text.
     59   ///
     60   const MCSection *TextSection;
     61 
     62   /// DataSection - Section directive for standard data.
     63   ///
     64   const MCSection *DataSection;
     65 
     66   /// BSSSection - Section that is default initialized to zero.
     67   const MCSection *BSSSection;
     68 
     69   /// ReadOnlySection - Section that is readonly and can contain arbitrary
     70   /// initialized data.  Targets are not required to have a readonly section.
     71   /// If they don't, various bits of code will fall back to using the data
     72   /// section for constants.
     73   const MCSection *ReadOnlySection;
     74 
     75   /// StaticCtorSection - This section contains the static constructor pointer
     76   /// list.
     77   const MCSection *StaticCtorSection;
     78 
     79   /// StaticDtorSection - This section contains the static destructor pointer
     80   /// list.
     81   const MCSection *StaticDtorSection;
     82 
     83   /// LSDASection - If exception handling is supported by the target, this is
     84   /// the section the Language Specific Data Area information is emitted to.
     85   const MCSection *LSDASection;
     86 
     87   /// CompactUnwindSection - If exception handling is supported by the target
     88   /// and the target can support a compact representation of the CIE and FDE,
     89   /// this is the section to emit them into.
     90   const MCSection *CompactUnwindSection;
     91 
     92   // Dwarf sections for debug info.  If a target supports debug info, these must
     93   // be set.
     94   const MCSection *DwarfAbbrevSection;
     95   const MCSection *DwarfInfoSection;
     96   const MCSection *DwarfLineSection;
     97   const MCSection *DwarfFrameSection;
     98   const MCSection *DwarfPubTypesSection;
     99   const MCSection *DwarfDebugInlineSection;
    100   const MCSection *DwarfStrSection;
    101   const MCSection *DwarfLocSection;
    102   const MCSection *DwarfARangesSection;
    103   const MCSection *DwarfRangesSection;
    104   const MCSection *DwarfMacroInfoSection;
    105   // The pubnames section is no longer generated by default.  The generation
    106   // can be enabled by a compiler flag.
    107   const MCSection *DwarfPubNamesSection;
    108 
    109   // DWARF5 Experimental Debug Info Sections
    110   /// DwarfAccelNamesSection, DwarfAccelObjCSection,
    111   /// DwarfAccelNamespaceSection, DwarfAccelTypesSection -
    112   /// If we use the DWARF accelerated hash tables then we want to emit these
    113   /// sections.
    114   const MCSection *DwarfAccelNamesSection;
    115   const MCSection *DwarfAccelObjCSection;
    116   const MCSection *DwarfAccelNamespaceSection;
    117   const MCSection *DwarfAccelTypesSection;
    118 
    119   /// These are used for the Fission separate debug information files.
    120   const MCSection *DwarfInfoDWOSection;
    121   const MCSection *DwarfAbbrevDWOSection;
    122   const MCSection *DwarfStrDWOSection;
    123   const MCSection *DwarfLineDWOSection;
    124   const MCSection *DwarfLocDWOSection;
    125   const MCSection *DwarfStrOffDWOSection;
    126   const MCSection *DwarfAddrSection;
    127 
    128   // Extra TLS Variable Data section.  If the target needs to put additional
    129   // information for a TLS variable, it'll go here.
    130   const MCSection *TLSExtraDataSection;
    131 
    132   /// TLSDataSection - Section directive for Thread Local data.
    133   /// ELF, MachO and COFF.
    134   const MCSection *TLSDataSection;        // Defaults to ".tdata".
    135 
    136   /// TLSBSSSection - Section directive for Thread Local uninitialized data.
    137   /// Null if this target doesn't support a BSS section.
    138   /// ELF and MachO only.
    139   const MCSection *TLSBSSSection;         // Defaults to ".tbss".
    140 
    141 
    142   /// EHFrameSection - EH frame section. It is initialized on demand so it
    143   /// can be overwritten (with uniquing).
    144   const MCSection *EHFrameSection;
    145 
    146   /// ELF specific sections.
    147   ///
    148   const MCSection *DataRelSection;
    149   const MCSection *DataRelLocalSection;
    150   const MCSection *DataRelROSection;
    151   const MCSection *DataRelROLocalSection;
    152   const MCSection *MergeableConst4Section;
    153   const MCSection *MergeableConst8Section;
    154   const MCSection *MergeableConst16Section;
    155 
    156   /// MachO specific sections.
    157   ///
    158 
    159   /// TLSTLVSection - Section for thread local structure information.
    160   /// Contains the source code name of the variable, visibility and a pointer
    161   /// to the initial value (.tdata or .tbss).
    162   const MCSection *TLSTLVSection;         // Defaults to ".tlv".
    163 
    164   /// TLSThreadInitSection - Section for thread local data initialization
    165   /// functions.
    166   const MCSection *TLSThreadInitSection;  // Defaults to ".thread_init_func".
    167 
    168   const MCSection *CStringSection;
    169   const MCSection *UStringSection;
    170   const MCSection *TextCoalSection;
    171   const MCSection *ConstTextCoalSection;
    172   const MCSection *ConstDataSection;
    173   const MCSection *DataCoalSection;
    174   const MCSection *DataCommonSection;
    175   const MCSection *DataBSSSection;
    176   const MCSection *FourByteConstantSection;
    177   const MCSection *EightByteConstantSection;
    178   const MCSection *SixteenByteConstantSection;
    179   const MCSection *LazySymbolPointerSection;
    180   const MCSection *NonLazySymbolPointerSection;
    181 
    182   /// COFF specific sections.
    183   ///
    184   const MCSection *DrectveSection;
    185   const MCSection *PDataSection;
    186   const MCSection *XDataSection;
    187 
    188 public:
    189   void InitMCObjectFileInfo(StringRef TT, Reloc::Model RM, CodeModel::Model CM,
    190                             MCContext &ctx);
    191 
    192   bool isFunctionEHFrameSymbolPrivate() const {
    193     return IsFunctionEHFrameSymbolPrivate;
    194   }
    195   bool getSupportsWeakOmittedEHFrame() const {
    196     return SupportsWeakOmittedEHFrame;
    197   }
    198   bool getCommDirectiveSupportsAlignment() const {
    199     return CommDirectiveSupportsAlignment;
    200   }
    201 
    202   unsigned getPersonalityEncoding() const { return PersonalityEncoding; }
    203   unsigned getLSDAEncoding() const { return LSDAEncoding; }
    204   unsigned getFDEEncoding(bool CFI) const {
    205     return CFI ? FDECFIEncoding : FDEEncoding;
    206   }
    207   unsigned getTTypeEncoding() const { return TTypeEncoding; }
    208 
    209   unsigned getCompactUnwindDwarfEHFrameOnly() const {
    210     return CompactUnwindDwarfEHFrameOnly;
    211   }
    212 
    213   const MCSection *getTextSection() const { return TextSection; }
    214   const MCSection *getDataSection() const { return DataSection; }
    215   const MCSection *getBSSSection() const { return BSSSection; }
    216   const MCSection *getLSDASection() const { return LSDASection; }
    217   const MCSection *getCompactUnwindSection() const{
    218     return CompactUnwindSection;
    219   }
    220   const MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
    221   const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
    222   const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
    223   const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
    224   const MCSection *getDwarfPubNamesSection() const{return DwarfPubNamesSection;}
    225   const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
    226   const MCSection *getDwarfDebugInlineSection() const {
    227     return DwarfDebugInlineSection;
    228   }
    229   const MCSection *getDwarfStrSection() const { return DwarfStrSection; }
    230   const MCSection *getDwarfLocSection() const { return DwarfLocSection; }
    231   const MCSection *getDwarfARangesSection() const { return DwarfARangesSection;}
    232   const MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
    233   const MCSection *getDwarfMacroInfoSection() const {
    234     return DwarfMacroInfoSection;
    235   }
    236 
    237   // DWARF5 Experimental Debug Info Sections
    238   const MCSection *getDwarfAccelNamesSection() const {
    239     return DwarfAccelNamesSection;
    240   }
    241   const MCSection *getDwarfAccelObjCSection() const {
    242     return DwarfAccelObjCSection;
    243   }
    244   const MCSection *getDwarfAccelNamespaceSection() const {
    245     return DwarfAccelNamespaceSection;
    246   }
    247   const MCSection *getDwarfAccelTypesSection() const {
    248     return DwarfAccelTypesSection;
    249   }
    250   const MCSection *getDwarfInfoDWOSection() const {
    251     return DwarfInfoDWOSection;
    252   }
    253   const MCSection *getDwarfAbbrevDWOSection() const {
    254     return DwarfAbbrevDWOSection;
    255   }
    256   const MCSection *getDwarfStrDWOSection() const {
    257     return DwarfStrDWOSection;
    258   }
    259   const MCSection *getDwarfLineDWOSection() const {
    260     return DwarfLineDWOSection;
    261   }
    262   const MCSection *getDwarfLocDWOSection() const {
    263     return DwarfLocDWOSection;
    264   }
    265   const MCSection *getDwarfStrOffDWOSection() const {
    266     return DwarfStrOffDWOSection;
    267   }
    268   const MCSection *getDwarfAddrSection() const {
    269     return DwarfAddrSection;
    270   }
    271 
    272   const MCSection *getTLSExtraDataSection() const {
    273     return TLSExtraDataSection;
    274   }
    275   const MCSection *getTLSDataSection() const { return TLSDataSection; }
    276   const MCSection *getTLSBSSSection() const { return TLSBSSSection; }
    277 
    278   /// ELF specific sections.
    279   ///
    280   const MCSection *getDataRelSection() const { return DataRelSection; }
    281   const MCSection *getDataRelLocalSection() const {
    282     return DataRelLocalSection;
    283   }
    284   const MCSection *getDataRelROSection() const { return DataRelROSection; }
    285   const MCSection *getDataRelROLocalSection() const {
    286     return DataRelROLocalSection;
    287   }
    288   const MCSection *getMergeableConst4Section() const {
    289     return MergeableConst4Section;
    290   }
    291   const MCSection *getMergeableConst8Section() const {
    292     return MergeableConst8Section;
    293   }
    294   const MCSection *getMergeableConst16Section() const {
    295     return MergeableConst16Section;
    296   }
    297 
    298   /// MachO specific sections.
    299   ///
    300   const MCSection *getTLSTLVSection() const { return TLSTLVSection; }
    301   const MCSection *getTLSThreadInitSection() const {
    302     return TLSThreadInitSection;
    303   }
    304   const MCSection *getCStringSection() const { return CStringSection; }
    305   const MCSection *getUStringSection() const { return UStringSection; }
    306   const MCSection *getTextCoalSection() const { return TextCoalSection; }
    307   const MCSection *getConstTextCoalSection() const {
    308     return ConstTextCoalSection;
    309   }
    310   const MCSection *getConstDataSection() const { return ConstDataSection; }
    311   const MCSection *getDataCoalSection() const { return DataCoalSection; }
    312   const MCSection *getDataCommonSection() const { return DataCommonSection; }
    313   const MCSection *getDataBSSSection() const { return DataBSSSection; }
    314   const MCSection *getFourByteConstantSection() const {
    315     return FourByteConstantSection;
    316   }
    317   const MCSection *getEightByteConstantSection() const {
    318     return EightByteConstantSection;
    319   }
    320   const MCSection *getSixteenByteConstantSection() const {
    321     return SixteenByteConstantSection;
    322   }
    323   const MCSection *getLazySymbolPointerSection() const {
    324     return LazySymbolPointerSection;
    325   }
    326   const MCSection *getNonLazySymbolPointerSection() const {
    327     return NonLazySymbolPointerSection;
    328   }
    329 
    330   /// COFF specific sections.
    331   ///
    332   const MCSection *getDrectveSection() const { return DrectveSection; }
    333   const MCSection *getPDataSection() const { return PDataSection; }
    334   const MCSection *getXDataSection() const { return XDataSection; }
    335 
    336   const MCSection *getEHFrameSection() {
    337     if (!EHFrameSection)
    338       InitEHFrameSection();
    339     return EHFrameSection;
    340   }
    341 
    342 private:
    343   enum Environment { IsMachO, IsELF, IsCOFF };
    344   Environment Env;
    345   Reloc::Model RelocM;
    346   CodeModel::Model CMModel;
    347   MCContext *Ctx;
    348 
    349   void InitMachOMCObjectFileInfo(Triple T);
    350   void InitELFMCObjectFileInfo(Triple T);
    351   void InitCOFFMCObjectFileInfo(Triple T);
    352 
    353   /// InitEHFrameSection - Initialize EHFrameSection on demand.
    354   ///
    355   void InitEHFrameSection();
    356 };
    357 
    358 } // end namespace llvm
    359 
    360 #endif
    361