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      1 //===- MCSymbolMachO.h -  ---------------------------------------*- 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 #ifndef LLVM_MC_MCSYMBOLMACHO_H
     10 #define LLVM_MC_MCSYMBOLMACHO_H
     11 
     12 #include "llvm/MC/MCSymbol.h"
     13 
     14 namespace llvm {
     15 class MCSymbolMachO : public MCSymbol {
     16   /// \brief We store the value for the 'desc' symbol field in the
     17   /// lowest 16 bits of the implementation defined flags.
     18   enum MachOSymbolFlags : uint16_t { // See <mach-o/nlist.h>.
     19     SF_DescFlagsMask                        = 0xFFFF,
     20 
     21     // Reference type flags.
     22     SF_ReferenceTypeMask                    = 0x0007,
     23     SF_ReferenceTypeUndefinedNonLazy        = 0x0000,
     24     SF_ReferenceTypeUndefinedLazy           = 0x0001,
     25     SF_ReferenceTypeDefined                 = 0x0002,
     26     SF_ReferenceTypePrivateDefined          = 0x0003,
     27     SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
     28     SF_ReferenceTypePrivateUndefinedLazy    = 0x0005,
     29 
     30     // Other 'desc' flags.
     31     SF_ThumbFunc                            = 0x0008,
     32     SF_NoDeadStrip                          = 0x0020,
     33     SF_WeakReference                        = 0x0040,
     34     SF_WeakDefinition                       = 0x0080,
     35     SF_SymbolResolver                       = 0x0100,
     36 
     37     // Common alignment
     38     SF_CommonAlignmentMask                  = 0xF0FF,
     39     SF_CommonAlignmentShift                 = 8
     40   };
     41 
     42 public:
     43   MCSymbolMachO(const StringMapEntry<bool> *Name, bool isTemporary)
     44       : MCSymbol(SymbolKindMachO, Name, isTemporary) {}
     45 
     46   // Reference type methods.
     47 
     48   void clearReferenceType() const {
     49     modifyFlags(0, SF_ReferenceTypeMask);
     50   }
     51 
     52   void setReferenceTypeUndefinedLazy(bool Value) const {
     53     modifyFlags(Value ? SF_ReferenceTypeUndefinedLazy : 0,
     54                 SF_ReferenceTypeUndefinedLazy);
     55   }
     56 
     57   // Other 'desc' methods.
     58 
     59   void setThumbFunc() const {
     60     modifyFlags(SF_ThumbFunc, SF_ThumbFunc);
     61   }
     62 
     63   bool isNoDeadStrip() const {
     64     return getFlags() & SF_NoDeadStrip;
     65   }
     66   void setNoDeadStrip() const {
     67     modifyFlags(SF_NoDeadStrip, SF_NoDeadStrip);
     68   }
     69 
     70   bool isWeakReference() const {
     71     return getFlags() & SF_WeakReference;
     72   }
     73   void setWeakReference() const {
     74     modifyFlags(SF_WeakReference, SF_WeakReference);
     75   }
     76 
     77   bool isWeakDefinition() const {
     78     return getFlags() & SF_WeakDefinition;
     79   }
     80   void setWeakDefinition() const {
     81     modifyFlags(SF_WeakDefinition, SF_WeakDefinition);
     82   }
     83 
     84   bool isSymbolResolver() const {
     85     return getFlags() & SF_SymbolResolver;
     86   }
     87   void setSymbolResolver() const {
     88     modifyFlags(SF_SymbolResolver, SF_SymbolResolver);
     89   }
     90 
     91   void setDesc(unsigned Value) const {
     92     assert(Value == (Value & SF_DescFlagsMask) &&
     93            "Invalid .desc value!");
     94     setFlags(Value & SF_DescFlagsMask);
     95   }
     96 
     97   /// \brief Get the encoded value of the flags as they will be emitted in to
     98   /// the MachO binary
     99   uint16_t getEncodedFlags() const {
    100     uint16_t Flags = getFlags();
    101 
    102     // Common alignment is packed into the 'desc' bits.
    103     if (isCommon()) {
    104       if (unsigned Align = getCommonAlignment()) {
    105         unsigned Log2Size = Log2_32(Align);
    106         assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
    107         if (Log2Size > 15)
    108           report_fatal_error("invalid 'common' alignment '" +
    109                              Twine(Align) + "' for '" + getName() + "'",
    110                              false);
    111         Flags = (Flags & SF_CommonAlignmentMask) |
    112                 (Log2Size << SF_CommonAlignmentShift);
    113       }
    114     }
    115 
    116     return Flags;
    117   }
    118 
    119   static bool classof(const MCSymbol *S) { return S->isMachO(); }
    120 };
    121 }
    122 
    123 #endif
    124