bench-branch.cc revision 4e7c93cc256c7719d69279d64e4f5d09044b8b2c 
1// Copyright 2015, 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 "globals-vixl.h"
28
29#include "aarch64/instructions-aarch64.h"
30#include "aarch64/macro-assembler-aarch64.h"
31
32using namespace vixl;
33using namespace vixl::aarch64;
34
35static const int kDefaultInstructionCount = 100000;
36
37// This program focuses on emitting branch instructions.
38//
39// This code will emit a given number of branch immediate to the next
40// instructions in a fixed size buffer, looping over the buffer if necessary.
41// This code therefore focuses on Emit and label binding/patching.
42int main(int argc, char* argv[]) {
43  int instructions = 0;
44
45  switch (argc) {
46    case 1:
47      instructions = kDefaultInstructionCount;
48      break;
49    case 2:
50      instructions = atoi(argv[1]);
51      break;
52    default:
53      printf("Usage: %s [#instructions]\n", argv[0]);
54      exit(1);
55  }
56
57  const int buffer_size = 256 * KBytes;
58  const int buffer_instruction_count = buffer_size / kInstructionSize;
59  MacroAssembler masm(buffer_size);
60
61#define __ masm.
62  // We emit a branch to the next instruction.
63
64  int rounds = instructions / buffer_instruction_count;
65  for (int i = 0; i < rounds; ++i) {
66    {
67      InstructionAccurateScope scope(&masm, buffer_instruction_count);
68      for (int j = 0; j < buffer_instruction_count; ++j) {
69        Label target;
70        __ b(&target);
71        __ bind(&target);
72      }
73    }
74    masm.Reset();
75  }
76
77  int remaining = instructions % buffer_instruction_count;
78  {
79    InstructionAccurateScope scope(&masm, remaining);
80    for (int i = 0; i < remaining; ++i) {
81      Label target;
82      __ b(&target);
83      __ bind(&target);
84    }
85  }
86
87  masm.FinalizeCode();
88
89  return 0;
90}
91