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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   /// If exception handling is supported by the target, this is the section the
     69   /// Language Specific Data Area information is emitted to.
     70   MCSection *LSDASection;
     71 
     72   /// If exception handling is supported by the target and the target can
     73   /// support a compact representation of the CIE and FDE, this is the section
     74   /// to emit them into.
     75   MCSection *CompactUnwindSection;
     76 
     77   // Dwarf sections for debug info.  If a target supports debug info, these must
     78   // be set.
     79   MCSection *DwarfAbbrevSection;
     80   MCSection *DwarfInfoSection;
     81   MCSection *DwarfLineSection;
     82   MCSection *DwarfFrameSection;
     83   MCSection *DwarfPubTypesSection;
     84   const MCSection *DwarfDebugInlineSection;
     85   MCSection *DwarfStrSection;
     86   MCSection *DwarfLocSection;
     87   MCSection *DwarfARangesSection;
     88   MCSection *DwarfRangesSection;
     89   MCSection *DwarfMacinfoSection;
     90   // The pubnames section is no longer generated by default.  The generation
     91   // can be enabled by a compiler flag.
     92   MCSection *DwarfPubNamesSection;
     93 
     94   /// DWARF5 Experimental Debug Info Sections
     95   /// DwarfAccelNamesSection, DwarfAccelObjCSection,
     96   /// DwarfAccelNamespaceSection, DwarfAccelTypesSection -
     97   /// If we use the DWARF accelerated hash tables then we want to emit these
     98   /// sections.
     99   MCSection *DwarfAccelNamesSection;
    100   MCSection *DwarfAccelObjCSection;
    101   MCSection *DwarfAccelNamespaceSection;
    102   MCSection *DwarfAccelTypesSection;
    103 
    104   // These are used for the Fission separate debug information files.
    105   MCSection *DwarfInfoDWOSection;
    106   MCSection *DwarfTypesDWOSection;
    107   MCSection *DwarfAbbrevDWOSection;
    108   MCSection *DwarfStrDWOSection;
    109   MCSection *DwarfLineDWOSection;
    110   MCSection *DwarfLocDWOSection;
    111   MCSection *DwarfStrOffDWOSection;
    112 
    113   /// The DWARF v5 string offset and address table sections.
    114   MCSection *DwarfStrOffSection;
    115   MCSection *DwarfAddrSection;
    116 
    117   // These are for Fission DWP files.
    118   MCSection *DwarfCUIndexSection;
    119   MCSection *DwarfTUIndexSection;
    120 
    121   /// Section for newer gnu pubnames.
    122   MCSection *DwarfGnuPubNamesSection;
    123   /// Section for newer gnu pubtypes.
    124   MCSection *DwarfGnuPubTypesSection;
    125 
    126   MCSection *COFFDebugSymbolsSection;
    127   MCSection *COFFDebugTypesSection;
    128 
    129   /// Extra TLS Variable Data section.
    130   ///
    131   /// If the target needs to put additional information for a TLS variable,
    132   /// it'll go here.
    133   MCSection *TLSExtraDataSection;
    134 
    135   /// Section directive for Thread Local data. ELF, MachO, COFF, and Wasm.
    136   MCSection *TLSDataSection; // Defaults to ".tdata".
    137 
    138   /// Section directive for Thread Local uninitialized data.
    139   ///
    140   /// Null if this target doesn't support a BSS section. ELF and MachO only.
    141   MCSection *TLSBSSSection; // Defaults to ".tbss".
    142 
    143   /// StackMap section.
    144   MCSection *StackMapSection;
    145 
    146   /// FaultMap section.
    147   MCSection *FaultMapSection;
    148 
    149   /// EH frame section.
    150   ///
    151   /// It is initialized on demand so it can be overwritten (with uniquing).
    152   MCSection *EHFrameSection;
    153 
    154   // ELF specific sections.
    155   MCSection *DataRelROSection;
    156   MCSection *MergeableConst4Section;
    157   MCSection *MergeableConst8Section;
    158   MCSection *MergeableConst16Section;
    159   MCSection *MergeableConst32Section;
    160 
    161   // MachO specific sections.
    162 
    163   /// Section for thread local structure information.
    164   ///
    165   /// Contains the source code name of the variable, visibility and a pointer to
    166   /// the initial value (.tdata or .tbss).
    167   MCSection *TLSTLVSection; // Defaults to ".tlv".
    168 
    169   /// Section for thread local data initialization functions.
    170   const MCSection *TLSThreadInitSection; // Defaults to ".thread_init_func".
    171 
    172   MCSection *CStringSection;
    173   MCSection *UStringSection;
    174   MCSection *TextCoalSection;
    175   MCSection *ConstTextCoalSection;
    176   MCSection *ConstDataSection;
    177   MCSection *DataCoalSection;
    178   MCSection *DataCommonSection;
    179   MCSection *DataBSSSection;
    180   MCSection *FourByteConstantSection;
    181   MCSection *EightByteConstantSection;
    182   MCSection *SixteenByteConstantSection;
    183   MCSection *LazySymbolPointerSection;
    184   MCSection *NonLazySymbolPointerSection;
    185   MCSection *ThreadLocalPointerSection;
    186 
    187   /// COFF specific sections.
    188   MCSection *DrectveSection;
    189   MCSection *PDataSection;
    190   MCSection *XDataSection;
    191   MCSection *SXDataSection;
    192 
    193 public:
    194   void InitMCObjectFileInfo(const Triple &TT, bool PIC, CodeModel::Model CM,
    195                             MCContext &ctx);
    196 
    197   bool getSupportsWeakOmittedEHFrame() const {
    198     return SupportsWeakOmittedEHFrame;
    199   }
    200   bool getSupportsCompactUnwindWithoutEHFrame() const {
    201     return SupportsCompactUnwindWithoutEHFrame;
    202   }
    203   bool getOmitDwarfIfHaveCompactUnwind() const {
    204     return OmitDwarfIfHaveCompactUnwind;
    205   }
    206 
    207   bool getCommDirectiveSupportsAlignment() const {
    208     return CommDirectiveSupportsAlignment;
    209   }
    210 
    211   unsigned getPersonalityEncoding() const { return PersonalityEncoding; }
    212   unsigned getLSDAEncoding() const { return LSDAEncoding; }
    213   unsigned getFDEEncoding() const { return FDECFIEncoding; }
    214   unsigned getTTypeEncoding() const { return TTypeEncoding; }
    215 
    216   unsigned getCompactUnwindDwarfEHFrameOnly() const {
    217     return CompactUnwindDwarfEHFrameOnly;
    218   }
    219 
    220   MCSection *getTextSection() const { return TextSection; }
    221   MCSection *getDataSection() const { return DataSection; }
    222   MCSection *getBSSSection() const { return BSSSection; }
    223   MCSection *getReadOnlySection() const { return ReadOnlySection; }
    224   MCSection *getLSDASection() const { return LSDASection; }
    225   MCSection *getCompactUnwindSection() const { return CompactUnwindSection; }
    226   MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
    227   MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
    228   MCSection *getDwarfLineSection() const { return DwarfLineSection; }
    229   MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
    230   MCSection *getDwarfPubNamesSection() const { return DwarfPubNamesSection; }
    231   MCSection *getDwarfPubTypesSection() const { return DwarfPubTypesSection; }
    232   MCSection *getDwarfGnuPubNamesSection() const {
    233     return DwarfGnuPubNamesSection;
    234   }
    235   MCSection *getDwarfGnuPubTypesSection() const {
    236     return DwarfGnuPubTypesSection;
    237   }
    238   const MCSection *getDwarfDebugInlineSection() const {
    239     return DwarfDebugInlineSection;
    240   }
    241   MCSection *getDwarfStrSection() const { return DwarfStrSection; }
    242   MCSection *getDwarfLocSection() const { return DwarfLocSection; }
    243   MCSection *getDwarfARangesSection() const { return DwarfARangesSection; }
    244   MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
    245   MCSection *getDwarfMacinfoSection() const { return DwarfMacinfoSection; }
    246 
    247   // DWARF5 Experimental Debug Info Sections
    248   MCSection *getDwarfAccelNamesSection() const {
    249     return DwarfAccelNamesSection;
    250   }
    251   MCSection *getDwarfAccelObjCSection() const { return DwarfAccelObjCSection; }
    252   MCSection *getDwarfAccelNamespaceSection() const {
    253     return DwarfAccelNamespaceSection;
    254   }
    255   MCSection *getDwarfAccelTypesSection() const {
    256     return DwarfAccelTypesSection;
    257   }
    258   MCSection *getDwarfInfoDWOSection() const { return DwarfInfoDWOSection; }
    259   MCSection *getDwarfTypesSection(uint64_t Hash) const;
    260   MCSection *getDwarfTypesDWOSection() const { return DwarfTypesDWOSection; }
    261   MCSection *getDwarfAbbrevDWOSection() const { return DwarfAbbrevDWOSection; }
    262   MCSection *getDwarfStrDWOSection() const { return DwarfStrDWOSection; }
    263   MCSection *getDwarfLineDWOSection() const { return DwarfLineDWOSection; }
    264   MCSection *getDwarfLocDWOSection() const { return DwarfLocDWOSection; }
    265   MCSection *getDwarfStrOffDWOSection() const { return DwarfStrOffDWOSection; }
    266   MCSection *getDwarfStrOffSection() const { return DwarfStrOffSection; }
    267   MCSection *getDwarfAddrSection() const { return DwarfAddrSection; }
    268   MCSection *getDwarfCUIndexSection() const { return DwarfCUIndexSection; }
    269   MCSection *getDwarfTUIndexSection() const { return DwarfTUIndexSection; }
    270 
    271   MCSection *getCOFFDebugSymbolsSection() const {
    272     return COFFDebugSymbolsSection;
    273   }
    274   MCSection *getCOFFDebugTypesSection() const {
    275     return COFFDebugTypesSection;
    276   }
    277 
    278 
    279   MCSection *getTLSExtraDataSection() const { return TLSExtraDataSection; }
    280   const MCSection *getTLSDataSection() const { return TLSDataSection; }
    281   MCSection *getTLSBSSSection() const { return TLSBSSSection; }
    282 
    283   MCSection *getStackMapSection() const { return StackMapSection; }
    284   MCSection *getFaultMapSection() const { return FaultMapSection; }
    285 
    286   // ELF specific sections.
    287   MCSection *getDataRelROSection() const { return DataRelROSection; }
    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   const MCSection *getMergeableConst32Section() const {
    298     return MergeableConst32Section;
    299   }
    300 
    301   // MachO specific sections.
    302   const MCSection *getTLSTLVSection() const { return TLSTLVSection; }
    303   const MCSection *getTLSThreadInitSection() const {
    304     return TLSThreadInitSection;
    305   }
    306   const MCSection *getCStringSection() const { return CStringSection; }
    307   const MCSection *getUStringSection() const { return UStringSection; }
    308   MCSection *getTextCoalSection() const { return TextCoalSection; }
    309   const MCSection *getConstTextCoalSection() const {
    310     return ConstTextCoalSection;
    311   }
    312   const MCSection *getConstDataSection() const { return ConstDataSection; }
    313   const MCSection *getDataCoalSection() const { return DataCoalSection; }
    314   const MCSection *getDataCommonSection() const { return DataCommonSection; }
    315   MCSection *getDataBSSSection() const { return DataBSSSection; }
    316   const MCSection *getFourByteConstantSection() const {
    317     return FourByteConstantSection;
    318   }
    319   const MCSection *getEightByteConstantSection() const {
    320     return EightByteConstantSection;
    321   }
    322   const MCSection *getSixteenByteConstantSection() const {
    323     return SixteenByteConstantSection;
    324   }
    325   MCSection *getLazySymbolPointerSection() const {
    326     return LazySymbolPointerSection;
    327   }
    328   MCSection *getNonLazySymbolPointerSection() const {
    329     return NonLazySymbolPointerSection;
    330   }
    331   MCSection *getThreadLocalPointerSection() const {
    332     return ThreadLocalPointerSection;
    333   }
    334 
    335   // COFF specific sections.
    336   MCSection *getDrectveSection() const { return DrectveSection; }
    337   MCSection *getPDataSection() const { return PDataSection; }
    338   MCSection *getXDataSection() const { return XDataSection; }
    339   MCSection *getSXDataSection() const { return SXDataSection; }
    340 
    341   MCSection *getEHFrameSection() {
    342     return EHFrameSection;
    343   }
    344 
    345   enum Environment { IsMachO, IsELF, IsCOFF, IsWasm };
    346   Environment getObjectFileType() const { return Env; }
    347 
    348   bool isPositionIndependent() const { return PositionIndependent; }
    349 
    350 private:
    351   Environment Env;
    352   bool PositionIndependent;
    353   CodeModel::Model CMModel;
    354   MCContext *Ctx;
    355   Triple TT;
    356 
    357   void initMachOMCObjectFileInfo(const Triple &T);
    358   void initELFMCObjectFileInfo(const Triple &T);
    359   void initCOFFMCObjectFileInfo(const Triple &T);
    360   void initWasmMCObjectFileInfo(const Triple &T);
    361 
    362 public:
    363   const Triple &getTargetTriple() const { return TT; }
    364 };
    365 
    366 } // end namespace llvm
    367 
    368 #endif
    369