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