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      1 // Copyright 2014, VIXL authors
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are met:
      6 //
      7 //   * Redistributions of source code must retain the above copyright notice,
      8 //     this list of conditions and the following disclaimer.
      9 //   * Redistributions in binary form must reproduce the above copyright notice,
     10 //     this list of conditions and the following disclaimer in the documentation
     11 //     and/or other materials provided with the distribution.
     12 //   * Neither the name of ARM Limited nor the names of its contributors may be
     13 //     used to endorse or promote products derived from this software without
     14 //     specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
     17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
     20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26 
     27 #include "non-const-visitor.h"
     28 #include "examples.h"
     29 
     30 #define __ masm->
     31 
     32 
     33 void GenerateNonConstVisitorTestCode(MacroAssembler* masm) {
     34   // int64_t foo(int64_t a, int64_t b)
     35   //  Argument locations:
     36   //    a -> x0
     37   //    b -> x1
     38   __ Sub(x0, x0, x1);
     39   // The return value is in x0.
     40   __ Ret();
     41 }
     42 
     43 
     44 int64_t RunNonConstVisitorTestGeneratedCode(const Instruction* start_instr) {
     45 #ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
     46   Decoder simulator_decoder;
     47   Simulator simulator(&simulator_decoder);
     48 
     49   int64_t a = 5;
     50   int64_t b = 2;
     51   simulator.WriteXRegister(0, a);
     52   simulator.WriteXRegister(1, b);
     53   simulator.RunFrom(start_instr);
     54   int64_t res = simulator.ReadXRegister(0);
     55   printf("foo(%" PRId64 ", %" PRId64 ") = %" PRId64 "\n", a, b, res);
     56 
     57   return res;
     58 #else
     59   // Without the simulator there is nothing to test.
     60   USE(start_instr);
     61   return 0;
     62 #endif
     63 }
     64 
     65 
     66 #ifndef TEST_EXAMPLES
     67 #ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
     68 int main(void) {
     69   MacroAssembler masm;
     70 
     71   // Generate the code.
     72   Label code_start, code_end;
     73   masm.Bind(&code_start);
     74   GenerateNonConstVisitorTestCode(&masm);
     75   masm.Bind(&code_end);
     76   masm.FinalizeCode();
     77   Instruction* instr_start = masm.GetLabelAddress<Instruction*>(&code_start);
     78   Instruction* instr_end = masm.GetLabelAddress<Instruction*>(&code_end);
     79 
     80   // Run the code a first time.
     81   RunNonConstVisitorTestGeneratedCode(instr_start);
     82 
     83   // Instantiate a decoder, disassembler, and our custom modifying visitor.
     84   Decoder decoder;
     85   PrintDisassembler disasm(stdout);
     86   SwitchAddSubRegisterSources modifying_visitor;
     87 
     88   // Register visitors in such a way that when visiting instructions, the
     89   // decoder will first disassemble the original instruction, modify it, and
     90   // then disassemble the modified instruction.
     91   decoder.AppendVisitor(&disasm);
     92   decoder.AppendVisitor(&modifying_visitor);
     93   decoder.AppendVisitor(&disasm);
     94 
     95   // Iterate through the instructions.
     96   Instruction* instr;
     97   for (instr = instr_start; instr < instr_end; instr += kInstructionSize) {
     98     printf("---\n");
     99     decoder.Decode(instr);
    100   }
    101 
    102   // Run the modified code and observe the different output from before.
    103   RunNonConstVisitorTestGeneratedCode(instr_start);
    104 
    105   return 0;
    106 }
    107 #else
    108 // Without the simulator there is nothing to test.
    109 int main(void) { return 0; }
    110 #endif  // VIXL_INCLUDE_SIMULATOR_AARCH64
    111 #endif  // TEST_EXAMPLES
    112 
    113 
    114 // This is only used by the testing code.
    115 void ModifyNonConstVisitorTestGeneratedCode(Instruction* start,
    116                                             Instruction* end) {
    117   Decoder decoder;
    118   SwitchAddSubRegisterSources modifying_visitor;
    119   decoder.AppendVisitor(&modifying_visitor);
    120 
    121   Instruction* instr;
    122   for (instr = start; instr < end; instr += kInstructionSize) {
    123     printf("---\n");
    124     decoder.Decode(instr);
    125   }
    126 }
    127