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https://github.com/KhronosGroup/SPIRV-Tools
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77fb303e58
Adds a fuzzer pass that inserts function calls into the module at random. Calls from dead blocks can be arbitrary (so long as they do not introduce recursion), while calls from other blocks can only be to livesafe functions. The change fixes some oversights in transformations to replace constants with uniforms and to obfuscate constants which testing of this fuzzer pass identified.
96 lines
3.7 KiB
C++
96 lines
3.7 KiB
C++
// Copyright (c) 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/fuzz/fuzzer_pass_add_loads.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/transformation_load.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassAddLoads::FuzzerPassAddLoads(
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opt::IRContext* ir_context, FactManager* fact_manager,
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FuzzerContext* fuzzer_context,
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protobufs::TransformationSequence* transformations)
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: FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {}
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FuzzerPassAddLoads::~FuzzerPassAddLoads() = default;
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void FuzzerPassAddLoads::Apply() {
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MaybeAddTransformationBeforeEachInstruction(
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[this](opt::Function* function, opt::BasicBlock* block,
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opt::BasicBlock::iterator inst_it,
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const protobufs::InstructionDescriptor& instruction_descriptor)
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-> void {
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assert(inst_it->opcode() ==
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instruction_descriptor.target_instruction_opcode() &&
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"The opcode of the instruction we might insert before must be "
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"the same as the opcode in the descriptor for the instruction");
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// Check whether it is legitimate to insert a load before this
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// instruction.
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if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpLoad, inst_it)) {
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return;
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}
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// Randomly decide whether to try inserting a load here.
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if (!GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAddingLoad())) {
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return;
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}
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std::vector<opt::Instruction*> relevant_instructions =
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FindAvailableInstructions(
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function, block, inst_it,
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[](opt::IRContext* context,
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opt::Instruction* instruction) -> bool {
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if (!instruction->result_id() || !instruction->type_id()) {
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return false;
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}
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switch (instruction->result_id()) {
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case SpvOpConstantNull:
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case SpvOpUndef:
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// Do not allow loading from a null or undefined pointer;
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// this might be OK if the block is dead, but for now we
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// conservatively avoid it.
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return false;
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default:
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break;
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}
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return context->get_def_use_mgr()
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->GetDef(instruction->type_id())
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->opcode() == SpvOpTypePointer;
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});
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// At this point, |relevant_instructions| contains all the pointers
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// we might think of loading from.
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if (relevant_instructions.empty()) {
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return;
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}
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// Choose a pointer at random, and create and apply a loading
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// transformation based on it.
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ApplyTransformation(TransformationLoad(
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GetFuzzerContext()->GetFreshId(),
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relevant_instructions[GetFuzzerContext()->RandomIndex(
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relevant_instructions)]
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->result_id(),
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instruction_descriptor));
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});
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}
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} // namespace fuzz
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} // namespace spvtools
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