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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/ADT/Twine.h"
     13 #include "llvm/MC/MCSymbol.h"
     14 
     15 namespace llvm {
     16 class MCSymbolMachO : public MCSymbol {
     17   /// \brief We store the value for the 'desc' symbol field in the
     18   /// lowest 16 bits of the implementation defined flags.
     19   enum MachOSymbolFlags : uint16_t { // See <mach-o/nlist.h>.
     20     SF_DescFlagsMask                        = 0xFFFF,
     21 
     22     // Reference type flags.
     23     SF_ReferenceTypeMask                    = 0x0007,
     24     SF_ReferenceTypeUndefinedNonLazy        = 0x0000,
     25     SF_ReferenceTypeUndefinedLazy           = 0x0001,
     26     SF_ReferenceTypeDefined                 = 0x0002,
     27     SF_ReferenceTypePrivateDefined          = 0x0003,
     28     SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
     29     SF_ReferenceTypePrivateUndefinedLazy    = 0x0005,
     30 
     31     // Other 'desc' flags.
     32     SF_ThumbFunc                            = 0x0008,
     33     SF_NoDeadStrip                          = 0x0020,
     34     SF_WeakReference                        = 0x0040,
     35     SF_WeakDefinition                       = 0x0080,
     36     SF_SymbolResolver                       = 0x0100,
     37     SF_AltEntry                             = 0x0200,
     38 
     39     // Common alignment
     40     SF_CommonAlignmentMask                  = 0xF0FF,
     41     SF_CommonAlignmentShift                 = 8
     42   };
     43 
     44 public:
     45   MCSymbolMachO(const StringMapEntry<bool> *Name, bool isTemporary)
     46       : MCSymbol(SymbolKindMachO, Name, isTemporary) {}
     47 
     48   // Reference type methods.
     49 
     50   void clearReferenceType() const {
     51     modifyFlags(0, SF_ReferenceTypeMask);
     52   }
     53 
     54   void setReferenceTypeUndefinedLazy(bool Value) const {
     55     modifyFlags(Value ? SF_ReferenceTypeUndefinedLazy : 0,
     56                 SF_ReferenceTypeUndefinedLazy);
     57   }
     58 
     59   // Other 'desc' methods.
     60 
     61   void setThumbFunc() const {
     62     modifyFlags(SF_ThumbFunc, SF_ThumbFunc);
     63   }
     64 
     65   bool isNoDeadStrip() const {
     66     return getFlags() & SF_NoDeadStrip;
     67   }
     68   void setNoDeadStrip() const {
     69     modifyFlags(SF_NoDeadStrip, SF_NoDeadStrip);
     70   }
     71 
     72   bool isWeakReference() const {
     73     return getFlags() & SF_WeakReference;
     74   }
     75   void setWeakReference() const {
     76     modifyFlags(SF_WeakReference, SF_WeakReference);
     77   }
     78 
     79   bool isWeakDefinition() const {
     80     return getFlags() & SF_WeakDefinition;
     81   }
     82   void setWeakDefinition() const {
     83     modifyFlags(SF_WeakDefinition, SF_WeakDefinition);
     84   }
     85 
     86   bool isSymbolResolver() const {
     87     return getFlags() & SF_SymbolResolver;
     88   }
     89   void setSymbolResolver() const {
     90     modifyFlags(SF_SymbolResolver, SF_SymbolResolver);
     91   }
     92 
     93   void setAltEntry() const {
     94     modifyFlags(SF_AltEntry, SF_AltEntry);
     95   }
     96 
     97   bool isAltEntry() const {
     98     return getFlags() & SF_AltEntry;
     99   }
    100 
    101   void setDesc(unsigned Value) const {
    102     assert(Value == (Value & SF_DescFlagsMask) &&
    103            "Invalid .desc value!");
    104     setFlags(Value & SF_DescFlagsMask);
    105   }
    106 
    107   /// \brief Get the encoded value of the flags as they will be emitted in to
    108   /// the MachO binary
    109   uint16_t getEncodedFlags(bool EncodeAsAltEntry) const {
    110     uint16_t Flags = getFlags();
    111 
    112     // Common alignment is packed into the 'desc' bits.
    113     if (isCommon()) {
    114       if (unsigned Align = getCommonAlignment()) {
    115         unsigned Log2Size = Log2_32(Align);
    116         assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
    117         if (Log2Size > 15)
    118           report_fatal_error("invalid 'common' alignment '" +
    119                              Twine(Align) + "' for '" + getName() + "'",
    120                              false);
    121         Flags = (Flags & SF_CommonAlignmentMask) |
    122                 (Log2Size << SF_CommonAlignmentShift);
    123       }
    124     }
    125 
    126     if (EncodeAsAltEntry)
    127       Flags |= SF_AltEntry;
    128 
    129     return Flags;
    130   }
    131 
    132   static bool classof(const MCSymbol *S) { return S->isMachO(); }
    133 };
    134 }
    135 
    136 #endif
    137