SPIRV-Tools/source/fuzz/transformation_vector_shuffle.cpp
Alastair Donaldson dc59b4b075
spirv-fuzz: vector shuffle transformation (#3015)
Inroduces a new transformation that adds a vector shuffle instruction
to the module, with associated facts about how the result vector of
the shuffle relates to the input vectors.

A fuzzer pass to add such transformations is not yet in place.
2019-11-06 17:11:54 +00:00

204 lines
7.9 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/transformation_vector_shuffle.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
namespace spvtools {
namespace fuzz {
TransformationVectorShuffle::TransformationVectorShuffle(
const spvtools::fuzz::protobufs::TransformationVectorShuffle& message)
: message_(message) {}
TransformationVectorShuffle::TransformationVectorShuffle(
const protobufs::InstructionDescriptor& instruction_to_insert_before,
uint32_t fresh_id, uint32_t vector1, uint32_t vector2,
const std::vector<uint32_t>& component) {
*message_.mutable_instruction_to_insert_before() =
instruction_to_insert_before;
message_.set_fresh_id(fresh_id);
message_.set_vector1(vector1);
message_.set_vector2(vector2);
for (auto a_component : component) {
message_.add_component(a_component);
}
}
bool TransformationVectorShuffle::IsApplicable(
opt::IRContext* context,
const spvtools::fuzz::FactManager& /*unused*/) const {
// The fresh id must not already be in use.
if (!fuzzerutil::IsFreshId(context, message_.fresh_id())) {
return false;
}
// The instruction before which the shuffle will be inserted must exist.
auto instruction_to_insert_before =
FindInstruction(message_.instruction_to_insert_before(), context);
if (!instruction_to_insert_before) {
return false;
}
// The first vector must be an instruction with a type id
auto vector1_instruction =
context->get_def_use_mgr()->GetDef(message_.vector1());
if (!vector1_instruction || !vector1_instruction->type_id()) {
return false;
}
// The second vector must be an instruction with a type id
auto vector2_instruction =
context->get_def_use_mgr()->GetDef(message_.vector2());
if (!vector2_instruction || !vector2_instruction->type_id()) {
return false;
}
auto vector1_type =
context->get_type_mgr()->GetType(vector1_instruction->type_id());
// The first vector instruction's type must actually be a vector type.
if (!vector1_type->AsVector()) {
return false;
}
auto vector2_type =
context->get_type_mgr()->GetType(vector2_instruction->type_id());
// The second vector instruction's type must actually be a vector type.
if (!vector2_type->AsVector()) {
return false;
}
// The element types of the vectors must be the same.
if (vector1_type->AsVector()->element_type() !=
vector2_type->AsVector()->element_type()) {
return false;
}
uint32_t combined_size = vector1_type->AsVector()->element_count() +
vector2_type->AsVector()->element_count();
for (auto a_compoment : message_.component()) {
// 0xFFFFFFFF is used to represent an undefined component. Unless
// undefined, a component must be less than the combined size of the
// vectors.
if (a_compoment != 0xFFFFFFFF && a_compoment >= combined_size) {
return false;
}
}
// The module must already declare an appropriate type in which to store the
// result of the shuffle.
if (!GetResultTypeId(context, *vector1_type->AsVector()->element_type())) {
return false;
}
// Each of the vectors used in the shuffle must be available at the insertion
// point.
for (auto used_instruction : {vector1_instruction, vector2_instruction}) {
if (auto block = context->get_instr_block(used_instruction)) {
if (!context->GetDominatorAnalysis(block->GetParent())
->Dominates(used_instruction, instruction_to_insert_before)) {
return false;
}
}
}
// It must be legitimate to insert an OpVectorShuffle before the identified
// instruction.
return fuzzerutil::CanInsertOpcodeBeforeInstruction(
SpvOpVectorShuffle, instruction_to_insert_before);
}
void TransformationVectorShuffle::Apply(
opt::IRContext* context, spvtools::fuzz::FactManager* fact_manager) const {
// Make input operands for a shuffle instruction - these comprise the two
// vectors being shuffled, followed by the integer literal components.
opt::Instruction::OperandList shuffle_operands = {
{SPV_OPERAND_TYPE_ID, {message_.vector1()}},
{SPV_OPERAND_TYPE_ID, {message_.vector2()}}};
for (auto a_component : message_.component()) {
shuffle_operands.push_back(
{SPV_OPERAND_TYPE_LITERAL_INTEGER, {a_component}});
}
uint32_t result_type_id = GetResultTypeId(
context, *GetVectorType(context, message_.vector1())->element_type());
// Add a shuffle instruction right before the instruction identified by
// |message_.instruction_to_insert_before|.
FindInstruction(message_.instruction_to_insert_before(), context)
->InsertBefore(MakeUnique<opt::Instruction>(
context, SpvOpVectorShuffle, result_type_id, message_.fresh_id(),
shuffle_operands));
fuzzerutil::UpdateModuleIdBound(context, message_.fresh_id());
context->InvalidateAnalysesExceptFor(opt::IRContext::Analysis::kAnalysisNone);
// Add synonym facts relating the defined elements of the shuffle result to
// the vector components that they come from.
for (uint32_t component_index = 0;
component_index < static_cast<uint32_t>(message_.component_size());
component_index++) {
uint32_t component = message_.component(component_index);
if (component == 0xFFFFFFFF) {
// This component is undefined, so move on - but first note that the
// overall shuffle result cannot be synonymous with any vector.
continue;
}
// This describes the element of the result vector associated with
// |component_index|.
protobufs::DataDescriptor descriptor_for_result_component =
MakeDataDescriptor(message_.fresh_id(), {component_index});
protobufs::DataDescriptor descriptor_for_source_component;
// Get a data descriptor for the component of the input vector to which
// |component| refers.
if (component <
GetVectorType(context, message_.vector1())->element_count()) {
descriptor_for_source_component =
MakeDataDescriptor(message_.vector1(), {component});
} else {
auto index_into_vector_2 =
component -
GetVectorType(context, message_.vector1())->element_count();
assert(index_into_vector_2 <
GetVectorType(context, message_.vector2())->element_count() &&
"Vector shuffle index is out of bounds.");
descriptor_for_source_component =
MakeDataDescriptor(message_.vector2(), {index_into_vector_2});
}
// Add a fact relating this input vector component with the associated
// result component.
fact_manager->AddFactDataSynonym(descriptor_for_result_component,
descriptor_for_source_component, context);
}
}
protobufs::Transformation TransformationVectorShuffle::ToMessage() const {
protobufs::Transformation result;
*result.mutable_vector_shuffle() = message_;
return result;
}
uint32_t TransformationVectorShuffle::GetResultTypeId(
opt::IRContext* context, const opt::analysis::Type& element_type) const {
opt::analysis::Vector result_type(
&element_type, static_cast<uint32_t>(message_.component_size()));
return context->get_type_mgr()->GetId(&result_type);
}
opt::analysis::Vector* TransformationVectorShuffle::GetVectorType(
opt::IRContext* context, uint32_t id_of_vector) {
return context->get_type_mgr()
->GetType(context->get_def_use_mgr()->GetDef(id_of_vector)->type_id())
->AsVector();
}
} // namespace fuzz
} // namespace spvtools