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:
MCSymbolMachO(const StringMapEntry<bool> * Name,bool isTemporary)45   MCSymbolMachO(const StringMapEntry<bool> *Name, bool isTemporary)
46       : MCSymbol(SymbolKindMachO, Name, isTemporary) {}
47 
48   // Reference type methods.
49 
clearReferenceType()50   void clearReferenceType() const {
51     modifyFlags(0, SF_ReferenceTypeMask);
52   }
53 
setReferenceTypeUndefinedLazy(bool Value)54   void setReferenceTypeUndefinedLazy(bool Value) const {
55     modifyFlags(Value ? SF_ReferenceTypeUndefinedLazy : 0,
56                 SF_ReferenceTypeUndefinedLazy);
57   }
58 
59   // Other 'desc' methods.
60 
setThumbFunc()61   void setThumbFunc() const {
62     modifyFlags(SF_ThumbFunc, SF_ThumbFunc);
63   }
64 
isNoDeadStrip()65   bool isNoDeadStrip() const {
66     return getFlags() & SF_NoDeadStrip;
67   }
setNoDeadStrip()68   void setNoDeadStrip() const {
69     modifyFlags(SF_NoDeadStrip, SF_NoDeadStrip);
70   }
71 
isWeakReference()72   bool isWeakReference() const {
73     return getFlags() & SF_WeakReference;
74   }
setWeakReference()75   void setWeakReference() const {
76     modifyFlags(SF_WeakReference, SF_WeakReference);
77   }
78 
isWeakDefinition()79   bool isWeakDefinition() const {
80     return getFlags() & SF_WeakDefinition;
81   }
setWeakDefinition()82   void setWeakDefinition() const {
83     modifyFlags(SF_WeakDefinition, SF_WeakDefinition);
84   }
85 
isSymbolResolver()86   bool isSymbolResolver() const {
87     return getFlags() & SF_SymbolResolver;
88   }
setSymbolResolver()89   void setSymbolResolver() const {
90     modifyFlags(SF_SymbolResolver, SF_SymbolResolver);
91   }
92 
setAltEntry()93   void setAltEntry() const {
94     modifyFlags(SF_AltEntry, SF_AltEntry);
95   }
96 
isAltEntry()97   bool isAltEntry() const {
98     return getFlags() & SF_AltEntry;
99   }
100 
setDesc(unsigned Value)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
getEncodedFlags(bool EncodeAsAltEntry)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 
classof(const MCSymbol * S)132   static bool classof(const MCSymbol *S) { return S->isMachO(); }
133 };
134 }
135 
136 #endif
137