1// Copyright (c) 2019 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "source/fuzz/fuzzer_pass_adjust_function_controls.h"
16
17#include "source/fuzz/transformation_set_function_control.h"
18
19namespace spvtools {
20namespace fuzz {
21
22FuzzerPassAdjustFunctionControls::FuzzerPassAdjustFunctionControls(
23    opt::IRContext* ir_context, TransformationContext* transformation_context,
24    FuzzerContext* fuzzer_context,
25    protobufs::TransformationSequence* transformations,
26    bool ignore_inapplicable_transformations)
27    : FuzzerPass(ir_context, transformation_context, fuzzer_context,
28                 transformations, ignore_inapplicable_transformations) {}
29
30void FuzzerPassAdjustFunctionControls::Apply() {
31  // Consider every function in the module.
32  for (auto& function : *GetIRContext()->module()) {
33    // Randomly decide whether to adjust this function's controls.
34    if (GetFuzzerContext()->ChoosePercentage(
35            GetFuzzerContext()->GetChanceOfAdjustingFunctionControl())) {
36      // Grab the function control mask for the function in its present form.
37      uint32_t existing_function_control_mask =
38          function.DefInst().GetSingleWordInOperand(0);
39
40      // For the new mask, we first randomly select one of three basic masks:
41      // None, Inline or DontInline.  These are always valid (and are mutually
42      // exclusive).
43      std::vector<spv::FunctionControlMask> basic_function_control_masks = {
44          spv::FunctionControlMask::MaskNone, spv::FunctionControlMask::Inline,
45          spv::FunctionControlMask::DontInline};
46      uint32_t new_function_control_mask =
47          uint32_t(basic_function_control_masks[GetFuzzerContext()->RandomIndex(
48              basic_function_control_masks)]);
49
50      // We now consider the Pure and Const mask bits.  If these are already
51      // set on the function then it's OK to keep them, but also interesting
52      // to consider dropping them, so we decide randomly in each case.
53      for (auto mask_bit :
54           {spv::FunctionControlMask::Pure, spv::FunctionControlMask::Const}) {
55        if ((existing_function_control_mask & uint32_t(mask_bit)) &&
56            GetFuzzerContext()->ChooseEven()) {
57          new_function_control_mask |= uint32_t(mask_bit);
58        }
59      }
60
61      // Create and add a transformation.
62      TransformationSetFunctionControl transformation(
63          function.DefInst().result_id(), new_function_control_mask);
64      ApplyTransformation(transformation);
65    }
66  }
67}
68
69}  // namespace fuzz
70}  // namespace spvtools
71