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26 
27 #ifndef VIXL_EXAMPLES_NON_CONST_VISITOR_H_
28 #define VIXL_EXAMPLES_NON_CONST_VISITOR_H_
29 
30 using namespace vixl;
31 
32 class SwitchAddSubRegisterSources : public DecoderVisitor {
33  public:
SwitchAddSubRegisterSources()34   SwitchAddSubRegisterSources()
35       : DecoderVisitor(DecoderVisitor::kNonConstVisitor) {}
36 
37   // Our visitor switches the register sources for some add and sub instructions
38   // (not all add and sub instructions). Visitors are listed by the macro
39   // `VISITOR_LIST` in a64/decoder-a64.h.
VisitAddSubShifted(const Instruction * instr)40   virtual void VisitAddSubShifted(const Instruction* instr) {
41     int rn = instr->Rn();
42     int rm = instr->Rm();
43     // Only non-const visitors are allowed to discard constness of the visited
44     // instruction.
45     Instruction* mutable_instr = MutableInstruction(instr);
46     Instr instr_bits = mutable_instr->InstructionBits();
47 
48     // Switch the bitfields for the `rn` and `rm` registers.
49     instr_bits &= ~(Rn_mask | Rm_mask);
50     instr_bits |= (rn << Rm_offset) | (rm << Rn_offset);
51 
52     // Rewrite the instruction.
53     mutable_instr->SetInstructionBits(instr_bits);
54   }
55 
56   // Define the remaining visitors to do nothing.
57 #define UNUSED_VISITOR_LIST(V)      \
58   V(PCRelAddressing)                \
59   V(AddSubImmediate)                \
60   V(LogicalImmediate)               \
61   V(MoveWideImmediate)              \
62   V(Bitfield)                       \
63   V(Extract)                        \
64   V(UnconditionalBranch)            \
65   V(UnconditionalBranchToRegister)  \
66   V(CompareBranch)                  \
67   V(TestBranch)                     \
68   V(ConditionalBranch)              \
69   V(System)                         \
70   V(Exception)                      \
71   V(LoadStorePairPostIndex)         \
72   V(LoadStorePairOffset)            \
73   V(LoadStorePairPreIndex)          \
74   V(LoadStorePairNonTemporal)       \
75   V(LoadLiteral)                    \
76   V(LoadStoreUnscaledOffset)        \
77   V(LoadStorePostIndex)             \
78   V(LoadStorePreIndex)              \
79   V(LoadStoreRegisterOffset)        \
80   V(LoadStoreUnsignedOffset)        \
81   V(LoadStoreExclusive)             \
82   V(LogicalShifted)                 \
83   V(AddSubExtended)                 \
84   V(AddSubWithCarry)                \
85   V(ConditionalCompareRegister)     \
86   V(ConditionalCompareImmediate)    \
87   V(ConditionalSelect)              \
88   V(DataProcessing1Source)          \
89   V(DataProcessing2Source)          \
90   V(DataProcessing3Source)          \
91   V(FPCompare)                      \
92   V(FPConditionalCompare)           \
93   V(FPConditionalSelect)            \
94   V(FPImmediate)                    \
95   V(FPDataProcessing1Source)        \
96   V(FPDataProcessing2Source)        \
97   V(FPDataProcessing3Source)        \
98   V(FPIntegerConvert)               \
99   V(FPFixedPointConvert)            \
100   V(Crypto2RegSHA)                  \
101   V(Crypto3RegSHA)                  \
102   V(CryptoAES)                      \
103   V(NEON2RegMisc)                   \
104   V(NEON3Different)                 \
105   V(NEON3Same)                      \
106   V(NEONAcrossLanes)                \
107   V(NEONByIndexedElement)           \
108   V(NEONCopy)                       \
109   V(NEONExtract)                    \
110   V(NEONLoadStoreMultiStruct)       \
111   V(NEONLoadStoreMultiStructPostIndex)  \
112   V(NEONLoadStoreSingleStruct)      \
113   V(NEONLoadStoreSingleStructPostIndex) \
114   V(NEONModifiedImmediate)          \
115   V(NEONScalar2RegMisc)             \
116   V(NEONScalar3Diff)                \
117   V(NEONScalar3Same)                \
118   V(NEONScalarByIndexedElement)     \
119   V(NEONScalarCopy)                 \
120   V(NEONScalarPairwise)             \
121   V(NEONScalarShiftImmediate)       \
122   V(NEONShiftImmediate)             \
123   V(NEONTable)                      \
124   V(NEONPerm)                       \
125   V(Unallocated)                    \
126   V(Unimplemented)
127 #define DEFINE_UNUSED_VISITOR(Name)                                  \
128   virtual void Visit##Name(const Instruction* i) {                   \
129     USE(i); /* Prevents compiler warnings about unused variables. */ \
130   }
131   UNUSED_VISITOR_LIST(DEFINE_UNUSED_VISITOR)
132 #undef DEFINE_UNUSED_VISITOR
133 #undef UNUSED_VISITOR_LIST
134 };
135 
136 
137 void GenerateNonConstVisitorTestCode(MacroAssembler* masm);
138 
139 int64_t RunNonConstVisitorTestGeneratedCode(const Instruction* start_instr);
140 
141 void ModifyNonConstVisitorTestGeneratedCode(Instruction* start,
142                                             Instruction* end);
143 
144 
145 #endif
146