SPIRV-Tools/source/fuzz/fuzzer_pass_copy_objects.cpp
Alastair Donaldson 77fb303e58
spirv-fuzz: Fuzzer pass to add function calls (#3178)
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.
2020-02-10 23:22:34 +00:00

77 lines
3.0 KiB
C++

// Copyright (c) 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/fuzz/fuzzer_pass_copy_objects.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/transformation_copy_object.h"
namespace spvtools {
namespace fuzz {
FuzzerPassCopyObjects::FuzzerPassCopyObjects(
opt::IRContext* ir_context, FactManager* fact_manager,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations)
: FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {}
FuzzerPassCopyObjects::~FuzzerPassCopyObjects() = default;
void FuzzerPassCopyObjects::Apply() {
MaybeAddTransformationBeforeEachInstruction(
[this](opt::Function* function, opt::BasicBlock* block,
opt::BasicBlock::iterator inst_it,
const protobufs::InstructionDescriptor& instruction_descriptor)
-> void {
assert(inst_it->opcode() ==
instruction_descriptor.target_instruction_opcode() &&
"The opcode of the instruction we might insert before must be "
"the same as the opcode in the descriptor for the instruction");
// Check whether it is legitimate to insert a copy before this
// instruction.
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpCopyObject,
inst_it)) {
return;
}
// Randomly decide whether to try inserting an object copy here.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfCopyingObject())) {
return;
}
std::vector<opt::Instruction*> relevant_instructions =
FindAvailableInstructions(function, block, inst_it,
fuzzerutil::CanMakeSynonymOf);
// At this point, |relevant_instructions| contains all the instructions
// we might think of copying.
if (relevant_instructions.empty()) {
return;
}
// Choose a copyable instruction at random, and create and apply an
// object copying transformation based on it.
ApplyTransformation(TransformationCopyObject(
relevant_instructions[GetFuzzerContext()->RandomIndex(
relevant_instructions)]
->result_id(),
instruction_descriptor, GetFuzzerContext()->GetFreshId()));
});
}
} // namespace fuzz
} // namespace spvtools