SPIRV-Tools/source/fuzz/fuzzer_pass_apply_id_synonyms.cpp
Alastair Donaldson 9e65f054d1
spirv-fuzz: Account for differing signedness in WrapVectorSynonym (#4414)
Makes the fuzzer pass and transformation that wraps vector synonyms
aware of the fact that integer operations can have arguments that
differ in signedness, and that the result type of such an operation
can have different sign from the argument types.

Fixes #4413.
2021-09-14 21:09:39 +00:00

207 lines
9.1 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_apply_id_synonyms.h"
#include "source/fuzz/data_descriptor.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/id_use_descriptor.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/transformation_composite_extract.h"
#include "source/fuzz/transformation_compute_data_synonym_fact_closure.h"
#include "source/fuzz/transformation_replace_id_with_synonym.h"
namespace spvtools {
namespace fuzz {
FuzzerPassApplyIdSynonyms::FuzzerPassApplyIdSynonyms(
opt::IRContext* ir_context, TransformationContext* transformation_context,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations,
bool ignore_inapplicable_transformations)
: FuzzerPass(ir_context, transformation_context, fuzzer_context,
transformations, ignore_inapplicable_transformations) {}
void FuzzerPassApplyIdSynonyms::Apply() {
// Compute a closure of data synonym facts, to enrich the pool of synonyms
// that are available.
ApplyTransformation(TransformationComputeDataSynonymFactClosure(
GetFuzzerContext()
->GetMaximumEquivalenceClassSizeForDataSynonymFactClosure()));
for (auto id_with_known_synonyms : GetTransformationContext()
->GetFactManager()
->GetIdsForWhichSynonymsAreKnown()) {
// Gather up all uses of |id_with_known_synonym| as a regular id, and
// subsequently iterate over these uses. We use this separation because,
// when considering a given use, we might apply a transformation that will
// invalidate the def-use manager.
std::vector<std::pair<opt::Instruction*, uint32_t>> uses;
GetIRContext()->get_def_use_mgr()->ForEachUse(
id_with_known_synonyms,
[&uses](opt::Instruction* use_inst, uint32_t use_index) -> void {
// We only gather up regular id uses; e.g. we do not include a use of
// the id as the scope for an atomic operation.
if (use_inst->GetOperand(use_index).type == SPV_OPERAND_TYPE_ID) {
uses.emplace_back(
std::pair<opt::Instruction*, uint32_t>(use_inst, use_index));
}
});
for (const auto& use : uses) {
auto use_inst = use.first;
auto use_index = use.second;
auto block_containing_use = GetIRContext()->get_instr_block(use_inst);
// The use might not be in a block; e.g. it could be a decoration.
if (!block_containing_use) {
continue;
}
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfReplacingIdWithSynonym())) {
continue;
}
// |use_index| is the absolute index of the operand. We require
// the index of the operand restricted to input operands only.
uint32_t use_in_operand_index =
fuzzerutil::InOperandIndexFromOperandIndex(*use_inst, use_index);
if (!fuzzerutil::IdUseCanBeReplaced(GetIRContext(),
*GetTransformationContext(), use_inst,
use_in_operand_index)) {
continue;
}
std::vector<const protobufs::DataDescriptor*> synonyms_to_try;
for (const auto* data_descriptor :
GetTransformationContext()->GetFactManager()->GetSynonymsForId(
id_with_known_synonyms)) {
protobufs::DataDescriptor descriptor_for_this_id =
MakeDataDescriptor(id_with_known_synonyms, {});
if (DataDescriptorEquals()(data_descriptor, &descriptor_for_this_id)) {
// Exclude the fact that the id is synonymous with itself.
continue;
}
if (DataDescriptorsHaveCompatibleTypes(
use_inst->opcode(), use_in_operand_index,
descriptor_for_this_id, *data_descriptor)) {
synonyms_to_try.push_back(data_descriptor);
}
}
while (!synonyms_to_try.empty()) {
auto synonym_to_try =
GetFuzzerContext()->RemoveAtRandomIndex(&synonyms_to_try);
// If the synonym's |index_size| is zero, the synonym represents an id.
// Otherwise it represents some element of a composite structure, in
// which case we need to be able to add an extract instruction to get
// that element out.
if (synonym_to_try->index_size() > 0 &&
!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpCompositeExtract,
use_inst) &&
use_inst->opcode() != SpvOpPhi) {
// We cannot insert an extract before this instruction, so this
// synonym is no good.
continue;
}
if (!fuzzerutil::IdIsAvailableAtUse(GetIRContext(), use_inst,
use_in_operand_index,
synonym_to_try->object())) {
continue;
}
// We either replace the use with an id known to be synonymous (when
// the synonym's |index_size| is 0), or an id that will hold the result
// of extracting a synonym from a composite (when the synonym's
// |index_size| is > 0).
uint32_t id_with_which_to_replace_use;
if (synonym_to_try->index_size() == 0) {
id_with_which_to_replace_use = synonym_to_try->object();
} else {
id_with_which_to_replace_use = GetFuzzerContext()->GetFreshId();
opt::Instruction* instruction_to_insert_before = nullptr;
if (use_inst->opcode() != SpvOpPhi) {
instruction_to_insert_before = use_inst;
} else {
auto parent_block_id =
use_inst->GetSingleWordInOperand(use_in_operand_index + 1);
auto parent_block_instruction =
GetIRContext()->get_def_use_mgr()->GetDef(parent_block_id);
auto parent_block =
GetIRContext()->get_instr_block(parent_block_instruction);
instruction_to_insert_before = parent_block->GetMergeInst()
? parent_block->GetMergeInst()
: parent_block->terminator();
}
if (GetTransformationContext()->GetFactManager()->BlockIsDead(
GetIRContext()
->get_instr_block(instruction_to_insert_before)
->id())) {
// We cannot create a synonym via a composite extraction in a dead
// block, as the resulting id is irrelevant.
continue;
}
assert(!GetTransformationContext()->GetFactManager()->IdIsIrrelevant(
synonym_to_try->object()) &&
"Irrelevant ids can't participate in DataSynonym facts");
ApplyTransformation(TransformationCompositeExtract(
MakeInstructionDescriptor(GetIRContext(),
instruction_to_insert_before),
id_with_which_to_replace_use, synonym_to_try->object(),
fuzzerutil::RepeatedFieldToVector(synonym_to_try->index())));
assert(GetTransformationContext()->GetFactManager()->IsSynonymous(
MakeDataDescriptor(id_with_which_to_replace_use, {}),
*synonym_to_try) &&
"The extracted id must be synonymous with the component from "
"which it was extracted.");
}
ApplyTransformation(TransformationReplaceIdWithSynonym(
MakeIdUseDescriptorFromUse(GetIRContext(), use_inst,
use_in_operand_index),
id_with_which_to_replace_use));
break;
}
}
}
}
bool FuzzerPassApplyIdSynonyms::DataDescriptorsHaveCompatibleTypes(
SpvOp opcode, uint32_t use_in_operand_index,
const protobufs::DataDescriptor& dd1,
const protobufs::DataDescriptor& dd2) {
auto base_object_type_id_1 =
fuzzerutil::GetTypeId(GetIRContext(), dd1.object());
auto base_object_type_id_2 =
fuzzerutil::GetTypeId(GetIRContext(), dd2.object());
assert(base_object_type_id_1 && base_object_type_id_2 &&
"Data descriptors are invalid");
auto type_id_1 = fuzzerutil::WalkCompositeTypeIndices(
GetIRContext(), base_object_type_id_1, dd1.index());
auto type_id_2 = fuzzerutil::WalkCompositeTypeIndices(
GetIRContext(), base_object_type_id_2, dd2.index());
assert(type_id_1 && type_id_2 && "Data descriptors have invalid types");
return fuzzerutil::TypesAreCompatible(
GetIRContext(), opcode, use_in_operand_index, type_id_1, type_id_2);
}
} // namespace fuzz
} // namespace spvtools