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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:
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 
setCold()101   void setCold() const { modifyFlags(SF_Cold, SF_Cold); }
102 
isCold()103   bool isCold() const { return getFlags() & SF_Cold; }
104 
setDesc(unsigned Value)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
getEncodedFlags(bool EncodeAsAltEntry)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 
classof(const MCSymbol * S)136   static bool classof(const MCSymbol *S) { return S->isMachO(); }
137 };
138 }
139 
140 #endif
141