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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_MCOBJECTFILEINFO_H
     15 #define LLVM_MC_MCOBJECTFILEINFO_H
     16 
     17 #include "llvm/ADT/Triple.h"
     18 #include "llvm/Support/CodeGen.h"
     19 
     20 namespace llvm {
     21 class MCContext;
     22 class MCSection;
     23 
     24 class MCObjectFileInfo {
     25 protected:
     26   /// True if .comm supports alignment.  This is a hack for as long as we
     27   /// support 10.4 Tiger, whose assembler doesn't support alignment on comm.
     28   bool CommDirectiveSupportsAlignment;
     29 
     30   /// True if target object file supports a weak_definition of constant 0 for an
     31   /// omitted EH frame.
     32   bool SupportsWeakOmittedEHFrame;
     33 
     34   /// True if the target object file supports emitting a compact unwind section
     35   /// without an associated EH frame section.
     36   bool SupportsCompactUnwindWithoutEHFrame;
     37 
     38   /// OmitDwarfIfHaveCompactUnwind - True if the target object file
     39   /// supports having some functions with compact unwind and other with
     40   /// dwarf unwind.
     41   bool OmitDwarfIfHaveCompactUnwind;
     42 
     43   /// PersonalityEncoding, LSDAEncoding, TTypeEncoding - Some encoding values
     44   /// for EH.
     45   unsigned PersonalityEncoding;
     46   unsigned LSDAEncoding;
     47   unsigned FDECFIEncoding;
     48   unsigned TTypeEncoding;
     49 
     50   /// Compact unwind encoding indicating that we should emit only an EH frame.
     51   unsigned CompactUnwindDwarfEHFrameOnly;
     52 
     53   /// Section directive for standard text.
     54   MCSection *TextSection;
     55 
     56   /// Section directive for standard data.
     57   MCSection *DataSection;
     58 
     59   /// Section that is default initialized to zero.
     60   MCSection *BSSSection;
     61 
     62   /// Section that is readonly and can contain arbitrary initialized data.
     63   /// Targets are not required to have a readonly section. If they don't,
     64   /// various bits of code will fall back to using the data section for
     65   /// constants.
     66   MCSection *ReadOnlySection;
     67 
     68   /// This section contains the static constructor pointer list.
     69   MCSection *StaticCtorSection;
     70 
     71   /// This section contains the static destructor pointer list.
     72   MCSection *StaticDtorSection;
     73 
     74   /// If exception handling is supported by the target, this is the section the
     75   /// Language Specific Data Area information is emitted to.
     76   MCSection *LSDASection;
     77 
     78   /// If exception handling is supported by the target and the target can
     79   /// support a compact representation of the CIE and FDE, this is the section
     80   /// to emit them into.
     81   MCSection *CompactUnwindSection;
     82 
     83   // Dwarf sections for debug info.  If a target supports debug info, these must
     84   // be set.
     85   MCSection *DwarfAbbrevSection;
     86   MCSection *DwarfInfoSection;
     87   MCSection *DwarfLineSection;
     88   MCSection *DwarfFrameSection;
     89   MCSection *DwarfPubTypesSection;
     90   const MCSection *DwarfDebugInlineSection;
     91   MCSection *DwarfStrSection;
     92   MCSection *DwarfLocSection;
     93   MCSection *DwarfARangesSection;
     94   MCSection *DwarfRangesSection;
     95   MCSection *DwarfMacinfoSection;
     96   // The pubnames section is no longer generated by default.  The generation
     97   // can be enabled by a compiler flag.
     98   MCSection *DwarfPubNamesSection;
     99 
    100   /// DWARF5 Experimental Debug Info Sections
    101   /// DwarfAccelNamesSection, DwarfAccelObjCSection,
    102   /// DwarfAccelNamespaceSection, DwarfAccelTypesSection -
    103   /// If we use the DWARF accelerated hash tables then we want to emit these
    104   /// sections.
    105   MCSection *DwarfAccelNamesSection;
    106   MCSection *DwarfAccelObjCSection;
    107   MCSection *DwarfAccelNamespaceSection;
    108   MCSection *DwarfAccelTypesSection;
    109 
    110   // These are used for the Fission separate debug information files.
    111   MCSection *DwarfInfoDWOSection;
    112   MCSection *DwarfTypesDWOSection;
    113   MCSection *DwarfAbbrevDWOSection;
    114   MCSection *DwarfStrDWOSection;
    115   MCSection *DwarfLineDWOSection;
    116   MCSection *DwarfLocDWOSection;
    117   MCSection *DwarfStrOffDWOSection;
    118   MCSection *DwarfAddrSection;
    119 
    120   // These are for Fission DWP files.
    121   MCSection *DwarfCUIndexSection;
    122   MCSection *DwarfTUIndexSection;
    123 
    124   /// Section for newer gnu pubnames.
    125   MCSection *DwarfGnuPubNamesSection;
    126   /// Section for newer gnu pubtypes.
    127   MCSection *DwarfGnuPubTypesSection;
    128 
    129   MCSection *COFFDebugSymbolsSection;
    130   MCSection *COFFDebugTypesSection;
    131 
    132   /// Extra TLS Variable Data section.
    133   ///
    134   /// If the target needs to put additional information for a TLS variable,
    135   /// it'll go here.
    136   MCSection *TLSExtraDataSection;
    137 
    138   /// Section directive for Thread Local data. ELF, MachO and COFF.
    139   MCSection *TLSDataSection; // Defaults to ".tdata".
    140 
    141   /// Section directive for Thread Local uninitialized data.
    142   ///
    143   /// Null if this target doesn't support a BSS section. ELF and MachO only.
    144   MCSection *TLSBSSSection; // Defaults to ".tbss".
    145 
    146   /// StackMap section.
    147   MCSection *StackMapSection;
    148 
    149   /// FaultMap section.
    150   MCSection *FaultMapSection;
    151 
    152   /// EH frame section.
    153   ///
    154   /// It is initialized on demand so it can be overwritten (with uniquing).
    155   MCSection *EHFrameSection;
    156 
    157   // ELF specific sections.
    158   MCSection *DataRelROSection;
    159   MCSection *MergeableConst4Section;
    160   MCSection *MergeableConst8Section;
    161   MCSection *MergeableConst16Section;
    162   MCSection *MergeableConst32Section;
    163 
    164   // MachO specific sections.
    165 
    166   /// Section for thread local structure information.
    167   ///
    168   /// Contains the source code name of the variable, visibility and a pointer to
    169   /// the initial value (.tdata or .tbss).
    170   MCSection *TLSTLVSection; // Defaults to ".tlv".
    171 
    172   /// Section for thread local data initialization functions.
    173   const MCSection *TLSThreadInitSection; // Defaults to ".thread_init_func".
    174 
    175   MCSection *CStringSection;
    176   MCSection *UStringSection;
    177   MCSection *TextCoalSection;
    178   MCSection *ConstTextCoalSection;
    179   MCSection *ConstDataSection;
    180   MCSection *DataCoalSection;
    181   MCSection *DataCommonSection;
    182   MCSection *DataBSSSection;
    183   MCSection *FourByteConstantSection;
    184   MCSection *EightByteConstantSection;
    185   MCSection *SixteenByteConstantSection;
    186   MCSection *LazySymbolPointerSection;
    187   MCSection *NonLazySymbolPointerSection;
    188   MCSection *ThreadLocalPointerSection;
    189 
    190   /// COFF specific sections.
    191   MCSection *DrectveSection;
    192   MCSection *PDataSection;
    193   MCSection *XDataSection;
    194   MCSection *SXDataSection;
    195 
    196 public:
    197   void InitMCObjectFileInfo(const Triple &TT, bool PIC, CodeModel::Model CM,
    198                             MCContext &ctx);
    199 
    200   bool getSupportsWeakOmittedEHFrame() const {
    201     return SupportsWeakOmittedEHFrame;
    202   }
    203   bool getSupportsCompactUnwindWithoutEHFrame() const {
    204     return SupportsCompactUnwindWithoutEHFrame;
    205   }
    206   bool getOmitDwarfIfHaveCompactUnwind() const {
    207     return OmitDwarfIfHaveCompactUnwind;
    208   }
    209 
    210   bool getCommDirectiveSupportsAlignment() const {
    211     return CommDirectiveSupportsAlignment;
    212   }
    213 
    214   unsigned getPersonalityEncoding() const { return PersonalityEncoding; }
    215   unsigned getLSDAEncoding() const { return LSDAEncoding; }
    216   unsigned getFDEEncoding() const { return FDECFIEncoding; }
    217   unsigned getTTypeEncoding() const { return TTypeEncoding; }
    218 
    219   unsigned getCompactUnwindDwarfEHFrameOnly() const {
    220     return CompactUnwindDwarfEHFrameOnly;
    221   }
    222 
    223   MCSection *getTextSection() const { return TextSection; }
    224   MCSection *getDataSection() const { return DataSection; }
    225   MCSection *getBSSSection() const { return BSSSection; }
    226   MCSection *getReadOnlySection() const { return ReadOnlySection; }
    227   MCSection *getLSDASection() const { return LSDASection; }
    228   MCSection *getCompactUnwindSection() const { return CompactUnwindSection; }
    229   MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
    230   MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
    231   MCSection *getDwarfLineSection() const { return DwarfLineSection; }
    232   MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
    233   MCSection *getDwarfPubNamesSection() const { return DwarfPubNamesSection; }
    234   MCSection *getDwarfPubTypesSection() const { return DwarfPubTypesSection; }
    235   MCSection *getDwarfGnuPubNamesSection() const {
    236     return DwarfGnuPubNamesSection;
    237   }
    238   MCSection *getDwarfGnuPubTypesSection() const {
    239     return DwarfGnuPubTypesSection;
    240   }
    241   const MCSection *getDwarfDebugInlineSection() const {
    242     return DwarfDebugInlineSection;
    243   }
    244   MCSection *getDwarfStrSection() const { return DwarfStrSection; }
    245   MCSection *getDwarfLocSection() const { return DwarfLocSection; }
    246   MCSection *getDwarfARangesSection() const { return DwarfARangesSection; }
    247   MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
    248   MCSection *getDwarfMacinfoSection() const { return DwarfMacinfoSection; }
    249 
    250   // DWARF5 Experimental Debug Info Sections
    251   MCSection *getDwarfAccelNamesSection() const {
    252     return DwarfAccelNamesSection;
    253   }
    254   MCSection *getDwarfAccelObjCSection() const { return DwarfAccelObjCSection; }
    255   MCSection *getDwarfAccelNamespaceSection() const {
    256     return DwarfAccelNamespaceSection;
    257   }
    258   MCSection *getDwarfAccelTypesSection() const {
    259     return DwarfAccelTypesSection;
    260   }
    261   MCSection *getDwarfInfoDWOSection() const { return DwarfInfoDWOSection; }
    262   MCSection *getDwarfTypesSection(uint64_t Hash) const;
    263   MCSection *getDwarfTypesDWOSection() const { return DwarfTypesDWOSection; }
    264   MCSection *getDwarfAbbrevDWOSection() const { return DwarfAbbrevDWOSection; }
    265   MCSection *getDwarfStrDWOSection() const { return DwarfStrDWOSection; }
    266   MCSection *getDwarfLineDWOSection() const { return DwarfLineDWOSection; }
    267   MCSection *getDwarfLocDWOSection() const { return DwarfLocDWOSection; }
    268   MCSection *getDwarfStrOffDWOSection() const { return DwarfStrOffDWOSection; }
    269   MCSection *getDwarfAddrSection() const { return DwarfAddrSection; }
    270   MCSection *getDwarfCUIndexSection() const { return DwarfCUIndexSection; }
    271   MCSection *getDwarfTUIndexSection() const { return DwarfTUIndexSection; }
    272 
    273   MCSection *getCOFFDebugSymbolsSection() const {
    274     return COFFDebugSymbolsSection;
    275   }
    276   MCSection *getCOFFDebugTypesSection() const {
    277     return COFFDebugTypesSection;
    278   }
    279 
    280 
    281   MCSection *getTLSExtraDataSection() const { return TLSExtraDataSection; }
    282   const MCSection *getTLSDataSection() const { return TLSDataSection; }
    283   MCSection *getTLSBSSSection() const { return TLSBSSSection; }
    284 
    285   MCSection *getStackMapSection() const { return StackMapSection; }
    286   MCSection *getFaultMapSection() const { return FaultMapSection; }
    287 
    288   // ELF specific sections.
    289   MCSection *getDataRelROSection() const { return DataRelROSection; }
    290   const MCSection *getMergeableConst4Section() const {
    291     return MergeableConst4Section;
    292   }
    293   const MCSection *getMergeableConst8Section() const {
    294     return MergeableConst8Section;
    295   }
    296   const MCSection *getMergeableConst16Section() const {
    297     return MergeableConst16Section;
    298   }
    299   const MCSection *getMergeableConst32Section() const {
    300     return MergeableConst32Section;
    301   }
    302 
    303   // MachO specific sections.
    304   const MCSection *getTLSTLVSection() const { return TLSTLVSection; }
    305   const MCSection *getTLSThreadInitSection() const {
    306     return TLSThreadInitSection;
    307   }
    308   const MCSection *getCStringSection() const { return CStringSection; }
    309   const MCSection *getUStringSection() const { return UStringSection; }
    310   MCSection *getTextCoalSection() const { return TextCoalSection; }
    311   const MCSection *getConstTextCoalSection() const {
    312     return ConstTextCoalSection;
    313   }
    314   const MCSection *getConstDataSection() const { return ConstDataSection; }
    315   const MCSection *getDataCoalSection() const { return DataCoalSection; }
    316   const MCSection *getDataCommonSection() const { return DataCommonSection; }
    317   MCSection *getDataBSSSection() const { return DataBSSSection; }
    318   const MCSection *getFourByteConstantSection() const {
    319     return FourByteConstantSection;
    320   }
    321   const MCSection *getEightByteConstantSection() const {
    322     return EightByteConstantSection;
    323   }
    324   const MCSection *getSixteenByteConstantSection() const {
    325     return SixteenByteConstantSection;
    326   }
    327   MCSection *getLazySymbolPointerSection() const {
    328     return LazySymbolPointerSection;
    329   }
    330   MCSection *getNonLazySymbolPointerSection() const {
    331     return NonLazySymbolPointerSection;
    332   }
    333   MCSection *getThreadLocalPointerSection() const {
    334     return ThreadLocalPointerSection;
    335   }
    336 
    337   // COFF specific sections.
    338   MCSection *getDrectveSection() const { return DrectveSection; }
    339   MCSection *getPDataSection() const { return PDataSection; }
    340   MCSection *getXDataSection() const { return XDataSection; }
    341   MCSection *getSXDataSection() const { return SXDataSection; }
    342 
    343   MCSection *getEHFrameSection() {
    344     return EHFrameSection;
    345   }
    346 
    347   enum Environment { IsMachO, IsELF, IsCOFF };
    348   Environment getObjectFileType() const { return Env; }
    349 
    350   bool isPositionIndependent() const { return PositionIndependent; }
    351 
    352 private:
    353   Environment Env;
    354   bool PositionIndependent;
    355   CodeModel::Model CMModel;
    356   MCContext *Ctx;
    357   Triple TT;
    358 
    359   void initMachOMCObjectFileInfo(const Triple &T);
    360   void initELFMCObjectFileInfo(const Triple &T);
    361   void initCOFFMCObjectFileInfo(const Triple &T);
    362 
    363 public:
    364   const Triple &getTargetTriple() const { return TT; }
    365 };
    366 
    367 } // end namespace llvm
    368 
    369 #endif
    370