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      1 //===- MCSymbolMachO.h -  ---------------------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 #ifndef LLVM_MC_MCSYMBOLMACHO_H
      9 #define LLVM_MC_MCSYMBOLMACHO_H
     10 
     11 #include "llvm/ADT/Twine.h"
     12 #include "llvm/MC/MCSymbol.h"
     13 
     14 namespace llvm {
     15 class MCSymbolMachO : public MCSymbol {
     16   /// 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     SF_AltEntry                             = 0x0200,
     37     SF_Cold                                 = 0x0400,
     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 setCold() const { modifyFlags(SF_Cold, SF_Cold); }
    102 
    103   bool isCold() const { return getFlags() & SF_Cold; }
    104 
    105   void setDesc(unsigned Value) const {
    106     assert(Value == (Value & SF_DescFlagsMask) &&
    107            "Invalid .desc value!");
    108     setFlags(Value & SF_DescFlagsMask);
    109   }
    110 
    111   /// Get the encoded value of the flags as they will be emitted in to
    112   /// the MachO binary
    113   uint16_t getEncodedFlags(bool EncodeAsAltEntry) const {
    114     uint16_t Flags = getFlags();
    115 
    116     // Common alignment is packed into the 'desc' bits.
    117     if (isCommon()) {
    118       if (unsigned Align = getCommonAlignment()) {
    119         unsigned Log2Size = Log2_32(Align);
    120         assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
    121         if (Log2Size > 15)
    122           report_fatal_error("invalid 'common' alignment '" +
    123                              Twine(Align) + "' for '" + getName() + "'",
    124                              false);
    125         Flags = (Flags & SF_CommonAlignmentMask) |
    126                 (Log2Size << SF_CommonAlignmentShift);
    127       }
    128     }
    129 
    130     if (EncodeAsAltEntry)
    131       Flags |= SF_AltEntry;
    132 
    133     return Flags;
    134   }
    135 
    136   static bool classof(const MCSymbol *S) { return S->isMachO(); }
    137 };
    138 }
    139 
    140 #endif
    141