mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-10-18 19:20:05 +00:00
9c4481419e
spirv-fuzz features transformations that should be applicable by construction. Assertions are used to detect when such transformations turn out to be inapplicable. Failures of such assertions indicate bugs in the fuzzer. However, when using the fuzzer at scale (e.g. in ClusterFuzz) reports of these assertion failures create noise, and cause the fuzzer to exit early. This change adds an option whereby inapplicable transformations can be ignored. This reduces noise and allows fuzzing to continue even when a transformation that should be applicable but is not has been erroneously created.
413 lines
17 KiB
C++
413 lines
17 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_equation_instructions.h"
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#include <vector>
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/transformation_equation_instruction.h"
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namespace spvtools {
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namespace fuzz {
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namespace {
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bool IsBitWidthSupported(opt::IRContext* ir_context, uint32_t bit_width) {
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switch (bit_width) {
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case 32:
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return true;
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case 64:
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return ir_context->get_feature_mgr()->HasCapability(
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SpvCapabilityFloat64) &&
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ir_context->get_feature_mgr()->HasCapability(SpvCapabilityInt64);
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case 16:
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return ir_context->get_feature_mgr()->HasCapability(
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SpvCapabilityFloat16) &&
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ir_context->get_feature_mgr()->HasCapability(SpvCapabilityInt16);
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default:
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return false;
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}
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}
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} // namespace
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FuzzerPassAddEquationInstructions::FuzzerPassAddEquationInstructions(
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opt::IRContext* ir_context, TransformationContext* transformation_context,
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FuzzerContext* fuzzer_context,
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protobufs::TransformationSequence* transformations,
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bool ignore_inapplicable_transformations)
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: FuzzerPass(ir_context, transformation_context, fuzzer_context,
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transformations, ignore_inapplicable_transformations) {}
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void FuzzerPassAddEquationInstructions::Apply() {
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ForEachInstructionWithInstructionDescriptor(
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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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if (!GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAddingEquationInstruction())) {
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return;
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}
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// Check that it is OK to add an equation instruction before the given
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// instruction in principle - e.g. check that this does not lead to
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// inserting before an OpVariable or OpPhi instruction. We use OpIAdd
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// as an example opcode for this check, to be representative of *some*
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// opcode that defines an equation, even though we may choose a
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// different opcode below.
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if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpIAdd, inst_it)) {
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return;
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}
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// Get all available instructions with result ids and types that are not
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// OpUndef.
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std::vector<opt::Instruction*> available_instructions =
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FindAvailableInstructions(
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function, block, inst_it,
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[this](opt::IRContext* /*unused*/,
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opt::Instruction* instruction) -> bool {
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return instruction->result_id() && instruction->type_id() &&
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instruction->opcode() != SpvOpUndef &&
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!GetTransformationContext()
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->GetFactManager()
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->IdIsIrrelevant(instruction->result_id());
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});
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// Try the opcodes for which we know how to make ids at random until
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// something works.
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std::vector<SpvOp> candidate_opcodes = {
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SpvOpIAdd, SpvOpISub, SpvOpLogicalNot, SpvOpSNegate,
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SpvOpConvertUToF, SpvOpConvertSToF, SpvOpBitcast};
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do {
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auto opcode =
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GetFuzzerContext()->RemoveAtRandomIndex(&candidate_opcodes);
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switch (opcode) {
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case SpvOpConvertSToF:
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case SpvOpConvertUToF: {
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std::vector<const opt::Instruction*> candidate_instructions;
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for (const auto* inst :
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GetIntegerInstructions(available_instructions)) {
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const auto* type =
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GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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assert(type && "|inst| has invalid type");
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if (const auto* vector_type = type->AsVector()) {
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type = vector_type->element_type();
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}
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if (IsBitWidthSupported(GetIRContext(),
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type->AsInteger()->width())) {
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candidate_instructions.push_back(inst);
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}
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}
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if (candidate_instructions.empty()) {
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break;
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}
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const auto* operand =
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candidate_instructions[GetFuzzerContext()->RandomIndex(
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candidate_instructions)];
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const auto* type =
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GetIRContext()->get_type_mgr()->GetType(operand->type_id());
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assert(type && "Operand has invalid type");
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// Make sure a result type exists in the module.
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if (const auto* vector = type->AsVector()) {
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// We store element count in a separate variable since the
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// call FindOrCreate* functions below might invalidate
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// |vector| pointer.
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const auto element_count = vector->element_count();
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FindOrCreateVectorType(
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FindOrCreateFloatType(
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vector->element_type()->AsInteger()->width()),
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element_count);
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} else {
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FindOrCreateFloatType(type->AsInteger()->width());
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}
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ApplyTransformation(TransformationEquationInstruction(
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GetFuzzerContext()->GetFreshId(), opcode,
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{operand->result_id()}, instruction_descriptor));
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return;
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}
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case SpvOpBitcast: {
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const auto candidate_instructions =
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GetNumericalInstructions(available_instructions);
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if (!candidate_instructions.empty()) {
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const auto* operand_inst =
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candidate_instructions[GetFuzzerContext()->RandomIndex(
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candidate_instructions)];
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const auto* operand_type =
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GetIRContext()->get_type_mgr()->GetType(
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operand_inst->type_id());
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assert(operand_type && "Operand instruction has invalid type");
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// Make sure a result type exists in the module.
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//
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// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/3539):
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// The only constraint on the types of OpBitcast's parameters
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// is that they must have the same number of bits. Consider
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// improving the code below to support this in full.
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if (const auto* vector = operand_type->AsVector()) {
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// We store element count in a separate variable since the
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// call FindOrCreate* functions below might invalidate
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// |vector| pointer.
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const auto element_count = vector->element_count();
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uint32_t element_type_id;
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if (const auto* int_type =
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vector->element_type()->AsInteger()) {
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element_type_id = FindOrCreateFloatType(int_type->width());
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} else {
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assert(vector->element_type()->AsFloat() &&
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"Vector must have numerical elements");
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element_type_id = FindOrCreateIntegerType(
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vector->element_type()->AsFloat()->width(),
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GetFuzzerContext()->ChooseEven());
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}
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FindOrCreateVectorType(element_type_id, element_count);
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} else if (const auto* int_type = operand_type->AsInteger()) {
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FindOrCreateFloatType(int_type->width());
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} else {
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assert(operand_type->AsFloat() &&
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"Operand is not a scalar of numerical type");
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FindOrCreateIntegerType(operand_type->AsFloat()->width(),
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GetFuzzerContext()->ChooseEven());
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}
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ApplyTransformation(TransformationEquationInstruction(
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GetFuzzerContext()->GetFreshId(), opcode,
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{operand_inst->result_id()}, instruction_descriptor));
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return;
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}
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} break;
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case SpvOpIAdd:
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case SpvOpISub: {
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// Instructions of integer (scalar or vector) result type are
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// suitable for these opcodes.
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auto integer_instructions =
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GetIntegerInstructions(available_instructions);
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if (!integer_instructions.empty()) {
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// There is at least one such instruction, so pick one at random
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// for the LHS of an equation.
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auto lhs = integer_instructions.at(
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GetFuzzerContext()->RandomIndex(integer_instructions));
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// For the RHS, we can use any instruction with an integer
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// scalar/vector result type of the same number of components
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// and the same bit-width for the underlying integer type.
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// Work out the element count and bit-width.
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auto lhs_type =
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GetIRContext()->get_type_mgr()->GetType(lhs->type_id());
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uint32_t lhs_element_count;
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uint32_t lhs_bit_width;
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if (lhs_type->AsVector()) {
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lhs_element_count = lhs_type->AsVector()->element_count();
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lhs_bit_width = lhs_type->AsVector()
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->element_type()
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->AsInteger()
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->width();
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} else {
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lhs_element_count = 1;
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lhs_bit_width = lhs_type->AsInteger()->width();
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}
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// Get all the instructions that match on element count and
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// bit-width.
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auto candidate_rhs_instructions = RestrictToElementBitWidth(
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RestrictToVectorWidth(integer_instructions,
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lhs_element_count),
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lhs_bit_width);
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// Choose a RHS instruction at random; there is guaranteed to
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// be at least one choice as the LHS will be available.
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auto rhs = candidate_rhs_instructions.at(
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GetFuzzerContext()->RandomIndex(
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candidate_rhs_instructions));
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// Add the equation instruction.
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ApplyTransformation(TransformationEquationInstruction(
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GetFuzzerContext()->GetFreshId(), opcode,
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{lhs->result_id(), rhs->result_id()},
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instruction_descriptor));
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return;
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}
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break;
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}
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case SpvOpLogicalNot: {
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// Choose any available instruction of boolean scalar/vector
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// result type and equate its negation with a fresh id.
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auto boolean_instructions =
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GetBooleanInstructions(available_instructions);
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if (!boolean_instructions.empty()) {
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ApplyTransformation(TransformationEquationInstruction(
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GetFuzzerContext()->GetFreshId(), opcode,
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{boolean_instructions
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.at(GetFuzzerContext()->RandomIndex(
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boolean_instructions))
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->result_id()},
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instruction_descriptor));
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return;
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}
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break;
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}
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case SpvOpSNegate: {
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// Similar to OpLogicalNot, but for signed integer negation.
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auto integer_instructions =
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GetIntegerInstructions(available_instructions);
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if (!integer_instructions.empty()) {
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ApplyTransformation(TransformationEquationInstruction(
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GetFuzzerContext()->GetFreshId(), opcode,
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{integer_instructions
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.at(GetFuzzerContext()->RandomIndex(
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integer_instructions))
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->result_id()},
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instruction_descriptor));
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return;
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}
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break;
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}
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default:
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assert(false && "Unexpected opcode.");
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break;
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}
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} while (!candidate_opcodes.empty());
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// Reaching here means that we did not manage to apply any
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// transformation at this point of the module.
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});
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::GetIntegerInstructions(
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const std::vector<opt::Instruction*>& instructions) const {
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std::vector<opt::Instruction*> result;
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for (auto& inst : instructions) {
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auto type = GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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if (type->AsInteger() ||
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(type->AsVector() && type->AsVector()->element_type()->AsInteger())) {
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result.push_back(inst);
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}
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}
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return result;
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::GetFloatInstructions(
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const std::vector<opt::Instruction*>& instructions) const {
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std::vector<opt::Instruction*> result;
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for (auto& inst : instructions) {
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auto type = GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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if (type->AsFloat() ||
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(type->AsVector() && type->AsVector()->element_type()->AsFloat())) {
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result.push_back(inst);
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}
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}
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return result;
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::GetBooleanInstructions(
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const std::vector<opt::Instruction*>& instructions) const {
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std::vector<opt::Instruction*> result;
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for (auto& inst : instructions) {
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auto type = GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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if (type->AsBool() ||
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(type->AsVector() && type->AsVector()->element_type()->AsBool())) {
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result.push_back(inst);
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}
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}
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return result;
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::RestrictToVectorWidth(
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const std::vector<opt::Instruction*>& instructions,
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uint32_t vector_width) const {
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std::vector<opt::Instruction*> result;
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for (auto& inst : instructions) {
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auto type = GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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// Get the vector width of |inst|, which is 1 if |inst| is a scalar and is
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// otherwise derived from its vector type.
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uint32_t other_vector_width =
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type->AsVector() ? type->AsVector()->element_count() : 1;
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// Keep |inst| if the vector widths match.
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if (vector_width == other_vector_width) {
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result.push_back(inst);
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}
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}
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return result;
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::RestrictToElementBitWidth(
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const std::vector<opt::Instruction*>& instructions,
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uint32_t bit_width) const {
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std::vector<opt::Instruction*> result;
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for (auto& inst : instructions) {
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const opt::analysis::Type* type =
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GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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if (type->AsVector()) {
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type = type->AsVector()->element_type();
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}
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assert((type->AsInteger() || type->AsFloat()) &&
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"Precondition: all input instructions must "
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"have integer or float scalar or vector type.");
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if ((type->AsInteger() && type->AsInteger()->width() == bit_width) ||
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(type->AsFloat() && type->AsFloat()->width() == bit_width)) {
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result.push_back(inst);
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}
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}
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return result;
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}
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std::vector<opt::Instruction*>
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FuzzerPassAddEquationInstructions::GetNumericalInstructions(
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const std::vector<opt::Instruction*>& instructions) const {
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std::vector<opt::Instruction*> result;
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for (auto* inst : instructions) {
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const auto* type = GetIRContext()->get_type_mgr()->GetType(inst->type_id());
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assert(type && "Instruction has invalid type");
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if (const auto* vector_type = type->AsVector()) {
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type = vector_type->element_type();
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}
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if (!type->AsInteger() && !type->AsFloat()) {
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// Only numerical scalars or vectors of numerical components are
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// supported.
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continue;
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}
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if (!IsBitWidthSupported(GetIRContext(), type->AsInteger()
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? type->AsInteger()->width()
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: type->AsFloat()->width())) {
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continue;
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}
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result.push_back(inst);
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}
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return result;
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}
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} // namespace fuzz
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} // namespace spvtools
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