mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-10-19 03:20:14 +00:00
e95fbfb1f5
Adds a transformation for adding OpConstantNull to a module, for appropriate data types.
758 lines
34 KiB
C++
758 lines
34 KiB
C++
// Copyright (c) 2019 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_donate_modules.h"
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#include <map>
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#include <queue>
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#include <set>
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#include "source/fuzz/call_graph.h"
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#include "source/fuzz/instruction_message.h"
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#include "source/fuzz/transformation_add_constant_boolean.h"
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#include "source/fuzz/transformation_add_constant_composite.h"
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#include "source/fuzz/transformation_add_constant_null.h"
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#include "source/fuzz/transformation_add_constant_scalar.h"
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#include "source/fuzz/transformation_add_function.h"
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#include "source/fuzz/transformation_add_global_undef.h"
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#include "source/fuzz/transformation_add_global_variable.h"
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#include "source/fuzz/transformation_add_type_array.h"
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#include "source/fuzz/transformation_add_type_boolean.h"
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#include "source/fuzz/transformation_add_type_float.h"
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#include "source/fuzz/transformation_add_type_function.h"
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#include "source/fuzz/transformation_add_type_int.h"
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#include "source/fuzz/transformation_add_type_matrix.h"
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#include "source/fuzz/transformation_add_type_pointer.h"
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#include "source/fuzz/transformation_add_type_struct.h"
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#include "source/fuzz/transformation_add_type_vector.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassDonateModules::FuzzerPassDonateModules(
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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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const std::vector<fuzzerutil::ModuleSupplier>& donor_suppliers)
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: FuzzerPass(ir_context, transformation_context, fuzzer_context,
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transformations),
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donor_suppliers_(donor_suppliers) {}
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FuzzerPassDonateModules::~FuzzerPassDonateModules() = default;
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void FuzzerPassDonateModules::Apply() {
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// If there are no donor suppliers, this fuzzer pass is a no-op.
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if (donor_suppliers_.empty()) {
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return;
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}
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// Donate at least one module, and probabilistically decide when to stop
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// donating modules.
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do {
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// Choose a donor supplier at random, and get the module that it provides.
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std::unique_ptr<opt::IRContext> donor_ir_context = donor_suppliers_.at(
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GetFuzzerContext()->RandomIndex(donor_suppliers_))();
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assert(donor_ir_context != nullptr && "Supplying of donor failed");
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assert(fuzzerutil::IsValid(
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donor_ir_context.get(),
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GetTransformationContext()->GetValidatorOptions()) &&
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"The donor module must be valid");
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// Donate the supplied module.
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//
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// Randomly decide whether to make the module livesafe (see
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// FactFunctionIsLivesafe); doing so allows it to be used for live code
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// injection but restricts its behaviour to allow this, and means that its
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// functions cannot be transformed as if they were arbitrary dead code.
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bool make_livesafe = GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->ChanceOfMakingDonorLivesafe());
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DonateSingleModule(donor_ir_context.get(), make_livesafe);
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} while (GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfDonatingAdditionalModule()));
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}
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void FuzzerPassDonateModules::DonateSingleModule(
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opt::IRContext* donor_ir_context, bool make_livesafe) {
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// The ids used by the donor module may very well clash with ids defined in
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// the recipient module. Furthermore, some instructions defined in the donor
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// module will be equivalent to instructions defined in the recipient module,
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// and it is not always legal to re-declare equivalent instructions. For
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// example, OpTypeVoid cannot be declared twice.
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//
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// To handle this, we maintain a mapping from an id used in the donor module
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// to the corresponding id that will be used by the donated code when it
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// appears in the recipient module.
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//
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// This mapping is populated in two ways:
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// (1) by mapping a donor instruction's result id to the id of some equivalent
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// existing instruction in the recipient (e.g. this has to be done for
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// OpTypeVoid)
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// (2) by mapping a donor instruction's result id to a freshly chosen id that
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// is guaranteed to be different from any id already used by the recipient
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// (or from any id already chosen to handle a previous donor id)
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std::map<uint32_t, uint32_t> original_id_to_donated_id;
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HandleExternalInstructionImports(donor_ir_context,
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&original_id_to_donated_id);
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HandleTypesAndValues(donor_ir_context, &original_id_to_donated_id);
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HandleFunctions(donor_ir_context, &original_id_to_donated_id, make_livesafe);
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// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/3115) Handle some
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// kinds of decoration.
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}
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SpvStorageClass FuzzerPassDonateModules::AdaptStorageClass(
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SpvStorageClass donor_storage_class) {
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switch (donor_storage_class) {
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case SpvStorageClassFunction:
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case SpvStorageClassPrivate:
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// We leave these alone
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return donor_storage_class;
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case SpvStorageClassInput:
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case SpvStorageClassOutput:
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case SpvStorageClassUniform:
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case SpvStorageClassUniformConstant:
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case SpvStorageClassPushConstant:
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// We change these to Private
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return SpvStorageClassPrivate;
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default:
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// Handle other cases on demand.
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assert(false && "Currently unsupported storage class.");
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return SpvStorageClassMax;
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}
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}
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void FuzzerPassDonateModules::HandleExternalInstructionImports(
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opt::IRContext* donor_ir_context,
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std::map<uint32_t, uint32_t>* original_id_to_donated_id) {
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// Consider every external instruction set import in the donor module.
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for (auto& donor_import : donor_ir_context->module()->ext_inst_imports()) {
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const auto& donor_import_name_words = donor_import.GetInOperand(0).words;
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// Look for an identical import in the recipient module.
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for (auto& existing_import : GetIRContext()->module()->ext_inst_imports()) {
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const auto& existing_import_name_words =
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existing_import.GetInOperand(0).words;
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if (donor_import_name_words == existing_import_name_words) {
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// A matching import has found. Map the result id for the donor import
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// to the id of the existing import, so that when donor instructions
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// rely on the import they will be rewritten to use the existing import.
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original_id_to_donated_id->insert(
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{donor_import.result_id(), existing_import.result_id()});
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break;
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}
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}
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// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/3116): At present
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// we do not handle donation of instruction imports, i.e. we do not allow
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// the donor to import instruction sets that the recipient did not already
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// import. It might be a good idea to allow this, but it requires some
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// thought.
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assert(original_id_to_donated_id->count(donor_import.result_id()) &&
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"Donation of imports is not yet supported.");
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}
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}
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void FuzzerPassDonateModules::HandleTypesAndValues(
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opt::IRContext* donor_ir_context,
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std::map<uint32_t, uint32_t>* original_id_to_donated_id) {
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// Consider every type/global/constant/undef in the module.
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for (auto& type_or_value : donor_ir_context->module()->types_values()) {
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// Each such instruction generates a result id, and as part of donation we
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// need to associate the donor's result id with a new result id. That new
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// result id will either be the id of some existing instruction, or a fresh
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// id. This variable captures it.
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uint32_t new_result_id;
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// Decide how to handle each kind of instruction on a case-by-case basis.
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//
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// Because the donor module is required to be valid, when we encounter a
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// type comprised of component types (e.g. an aggregate or pointer), we know
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// that its component types will have been considered previously, and that
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// |original_id_to_donated_id| will already contain an entry for them.
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switch (type_or_value.opcode()) {
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case SpvOpTypeVoid: {
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// Void has to exist already in order for us to have an entry point.
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// Get the existing id of void.
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opt::analysis::Void void_type;
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new_result_id = GetIRContext()->get_type_mgr()->GetId(&void_type);
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assert(new_result_id &&
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"The module being transformed will always have 'void' type "
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"declared.");
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} break;
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case SpvOpTypeBool: {
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// Bool cannot be declared multiple times, so use its existing id if
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// present, or add a declaration of Bool with a fresh id if not.
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opt::analysis::Bool bool_type;
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auto bool_type_id = GetIRContext()->get_type_mgr()->GetId(&bool_type);
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if (bool_type_id) {
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new_result_id = bool_type_id;
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} else {
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypeBoolean(new_result_id));
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}
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} break;
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case SpvOpTypeInt: {
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// Int cannot be declared multiple times with the same width and
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// signedness, so check whether an existing identical Int type is
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// present and use its id if so. Otherwise add a declaration of the
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// Int type used by the donor, with a fresh id.
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const uint32_t width = type_or_value.GetSingleWordInOperand(0);
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const bool is_signed =
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static_cast<bool>(type_or_value.GetSingleWordInOperand(1));
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opt::analysis::Integer int_type(width, is_signed);
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auto int_type_id = GetIRContext()->get_type_mgr()->GetId(&int_type);
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if (int_type_id) {
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new_result_id = int_type_id;
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} else {
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(
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TransformationAddTypeInt(new_result_id, width, is_signed));
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}
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} break;
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case SpvOpTypeFloat: {
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// Similar to SpvOpTypeInt.
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const uint32_t width = type_or_value.GetSingleWordInOperand(0);
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opt::analysis::Float float_type(width);
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auto float_type_id = GetIRContext()->get_type_mgr()->GetId(&float_type);
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if (float_type_id) {
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new_result_id = float_type_id;
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} else {
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypeFloat(new_result_id, width));
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}
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} break;
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case SpvOpTypeVector: {
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// It is not legal to have two Vector type declarations with identical
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// element types and element counts, so check whether an existing
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// identical Vector type is present and use its id if so. Otherwise add
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// a declaration of the Vector type used by the donor, with a fresh id.
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// When considering the vector's component type id, we look up the id
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// use in the donor to find the id to which this has been remapped.
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uint32_t component_type_id = original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(0));
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auto component_type =
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GetIRContext()->get_type_mgr()->GetType(component_type_id);
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assert(component_type && "The base type should be registered.");
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auto component_count = type_or_value.GetSingleWordInOperand(1);
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opt::analysis::Vector vector_type(component_type, component_count);
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auto vector_type_id =
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GetIRContext()->get_type_mgr()->GetId(&vector_type);
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if (vector_type_id) {
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new_result_id = vector_type_id;
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} else {
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypeVector(
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new_result_id, component_type_id, component_count));
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}
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} break;
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case SpvOpTypeMatrix: {
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// Similar to SpvOpTypeVector.
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uint32_t column_type_id = original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(0));
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auto column_type =
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GetIRContext()->get_type_mgr()->GetType(column_type_id);
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assert(column_type && column_type->AsVector() &&
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"The column type should be a registered vector type.");
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auto column_count = type_or_value.GetSingleWordInOperand(1);
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opt::analysis::Matrix matrix_type(column_type, column_count);
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auto matrix_type_id =
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GetIRContext()->get_type_mgr()->GetId(&matrix_type);
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if (matrix_type_id) {
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new_result_id = matrix_type_id;
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} else {
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypeMatrix(
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new_result_id, column_type_id, column_count));
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}
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} break;
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case SpvOpTypeArray: {
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// It is OK to have multiple structurally identical array types, so
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// we go ahead and add a remapped version of the type declared by the
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// donor.
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypeArray(
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new_result_id,
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original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(0)),
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original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(1))));
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} break;
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case SpvOpTypeStruct: {
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// Similar to SpvOpTypeArray.
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new_result_id = GetFuzzerContext()->GetFreshId();
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std::vector<uint32_t> member_type_ids;
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type_or_value.ForEachInId(
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[&member_type_ids,
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&original_id_to_donated_id](const uint32_t* component_type_id) {
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member_type_ids.push_back(
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original_id_to_donated_id->at(*component_type_id));
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});
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ApplyTransformation(
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TransformationAddTypeStruct(new_result_id, member_type_ids));
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} break;
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case SpvOpTypePointer: {
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// Similar to SpvOpTypeArray.
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypePointer(
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new_result_id,
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AdaptStorageClass(static_cast<SpvStorageClass>(
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type_or_value.GetSingleWordInOperand(0))),
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original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(1))));
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} break;
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case SpvOpTypeFunction: {
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// It is not OK to have multiple function types that use identical ids
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// for their return and parameter types. We thus go through all
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// existing function types to look for a match. We do not use the
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// type manager here because we want to regard two function types that
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// are structurally identical but that differ with respect to the
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// actual ids used for pointer types as different.
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//
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// Example:
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//
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// %1 = OpTypeVoid
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// %2 = OpTypeInt 32 0
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// %3 = OpTypePointer Function %2
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// %4 = OpTypePointer Function %2
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// %5 = OpTypeFunction %1 %3
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// %6 = OpTypeFunction %1 %4
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//
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// We regard %5 and %6 as distinct function types here, even though
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// they both have the form "uint32* -> void"
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std::vector<uint32_t> return_and_parameter_types;
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for (uint32_t i = 0; i < type_or_value.NumInOperands(); i++) {
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return_and_parameter_types.push_back(original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(i)));
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}
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uint32_t existing_function_id = fuzzerutil::FindFunctionType(
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GetIRContext(), return_and_parameter_types);
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if (existing_function_id) {
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new_result_id = existing_function_id;
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} else {
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// No match was found, so add a remapped version of the function type
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// to the module, with a fresh id.
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new_result_id = GetFuzzerContext()->GetFreshId();
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std::vector<uint32_t> argument_type_ids;
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for (uint32_t i = 1; i < type_or_value.NumInOperands(); i++) {
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argument_type_ids.push_back(original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(i)));
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}
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ApplyTransformation(TransformationAddTypeFunction(
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new_result_id,
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original_id_to_donated_id->at(
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type_or_value.GetSingleWordInOperand(0)),
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argument_type_ids));
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}
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} break;
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case SpvOpConstantTrue:
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case SpvOpConstantFalse: {
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// It is OK to have duplicate definitions of True and False, so add
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// these to the module, using a remapped Bool type.
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddConstantBoolean(
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new_result_id, type_or_value.opcode() == SpvOpConstantTrue));
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} break;
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case SpvOpConstant: {
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// It is OK to have duplicate constant definitions, so add this to the
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// module using a remapped result type.
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new_result_id = GetFuzzerContext()->GetFreshId();
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std::vector<uint32_t> data_words;
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type_or_value.ForEachInOperand(
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[&data_words](const uint32_t* in_operand) {
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data_words.push_back(*in_operand);
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});
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ApplyTransformation(TransformationAddConstantScalar(
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new_result_id,
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original_id_to_donated_id->at(type_or_value.type_id()),
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data_words));
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} break;
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case SpvOpConstantComposite: {
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// It is OK to have duplicate constant composite definitions, so add
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// this to the module using remapped versions of all consituent ids and
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// the result type.
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new_result_id = GetFuzzerContext()->GetFreshId();
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std::vector<uint32_t> constituent_ids;
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type_or_value.ForEachInId(
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[&constituent_ids,
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&original_id_to_donated_id](const uint32_t* constituent_id) {
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constituent_ids.push_back(
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original_id_to_donated_id->at(*constituent_id));
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});
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ApplyTransformation(TransformationAddConstantComposite(
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new_result_id,
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original_id_to_donated_id->at(type_or_value.type_id()),
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constituent_ids));
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} break;
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case SpvOpConstantNull: {
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if (!original_id_to_donated_id->count(type_or_value.type_id())) {
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// We did not donate the type associated with this null constant, so
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// we cannot donate the null constant.
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continue;
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}
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// It is fine to have multiple OpConstantNull instructions of the same
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// type, so we just add this to the recipient module.
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new_result_id = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddConstantNull(
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new_result_id,
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original_id_to_donated_id->at(type_or_value.type_id())));
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} break;
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case SpvOpVariable: {
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// This is a global variable that could have one of various storage
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// classes. However, we change all global variable pointer storage
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// classes (such as Uniform, Input and Output) to private when donating
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// pointer types. Thus this variable's pointer type is guaranteed to
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// have storage class private. As a result, we simply add a Private
|
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// storage class global variable, using remapped versions of the result
|
||
// type and initializer ids for the global variable in the donor.
|
||
//
|
||
// We regard the added variable as having an irrelevant value. This
|
||
// means that future passes can add stores to the variable in any
|
||
// way they wish, and pass them as pointer parameters to functions
|
||
// without worrying about whether their data might get modified.
|
||
new_result_id = GetFuzzerContext()->GetFreshId();
|
||
uint32_t remapped_pointer_type =
|
||
original_id_to_donated_id->at(type_or_value.type_id());
|
||
uint32_t initializer_id;
|
||
if (type_or_value.NumInOperands() == 1) {
|
||
// The variable did not have an initializer; initialize it to zero.
|
||
// This is to limit problems associated with uninitialized data.
|
||
initializer_id = FindOrCreateZeroConstant(
|
||
fuzzerutil::GetPointeeTypeIdFromPointerType(
|
||
GetIRContext(), remapped_pointer_type));
|
||
} else {
|
||
// The variable already had an initializer; use its remapped id.
|
||
initializer_id = original_id_to_donated_id->at(
|
||
type_or_value.GetSingleWordInOperand(1));
|
||
}
|
||
ApplyTransformation(TransformationAddGlobalVariable(
|
||
new_result_id, remapped_pointer_type, initializer_id, true));
|
||
} break;
|
||
case SpvOpUndef: {
|
||
// It is fine to have multiple Undef instructions of the same type, so
|
||
// we just add this to the recipient module.
|
||
new_result_id = GetFuzzerContext()->GetFreshId();
|
||
ApplyTransformation(TransformationAddGlobalUndef(
|
||
new_result_id,
|
||
original_id_to_donated_id->at(type_or_value.type_id())));
|
||
} break;
|
||
default: {
|
||
assert(0 && "Unknown type/value.");
|
||
new_result_id = 0;
|
||
} break;
|
||
}
|
||
// Update the id mapping to associate the instruction's result id with its
|
||
// corresponding id in the recipient.
|
||
original_id_to_donated_id->insert(
|
||
{type_or_value.result_id(), new_result_id});
|
||
}
|
||
}
|
||
|
||
void FuzzerPassDonateModules::HandleFunctions(
|
||
opt::IRContext* donor_ir_context,
|
||
std::map<uint32_t, uint32_t>* original_id_to_donated_id,
|
||
bool make_livesafe) {
|
||
// Get the ids of functions in the donor module, topologically sorted
|
||
// according to the donor's call graph.
|
||
auto topological_order =
|
||
GetFunctionsInCallGraphTopologicalOrder(donor_ir_context);
|
||
|
||
// Donate the functions in reverse topological order. This ensures that a
|
||
// function gets donated before any function that depends on it. This allows
|
||
// donation of the functions to be separated into a number of transformations,
|
||
// each adding one function, such that every prefix of transformations leaves
|
||
// the module valid.
|
||
for (auto function_id = topological_order.rbegin();
|
||
function_id != topological_order.rend(); ++function_id) {
|
||
// Find the function to be donated.
|
||
opt::Function* function_to_donate = nullptr;
|
||
for (auto& function : *donor_ir_context->module()) {
|
||
if (function.result_id() == *function_id) {
|
||
function_to_donate = &function;
|
||
break;
|
||
}
|
||
}
|
||
assert(function_to_donate && "Function to be donated was not found.");
|
||
|
||
// We will collect up protobuf messages representing the donor function's
|
||
// instructions here, and use them to create an AddFunction transformation.
|
||
std::vector<protobufs::Instruction> donated_instructions;
|
||
|
||
// Scan through the function, remapping each result id that it generates to
|
||
// a fresh id. This is necessary because functions include forward
|
||
// references, e.g. to labels.
|
||
function_to_donate->ForEachInst([this, &original_id_to_donated_id](
|
||
const opt::Instruction* instruction) {
|
||
if (instruction->result_id()) {
|
||
original_id_to_donated_id->insert(
|
||
{instruction->result_id(), GetFuzzerContext()->GetFreshId()});
|
||
}
|
||
});
|
||
|
||
// Consider every instruction of the donor function.
|
||
function_to_donate->ForEachInst([this, &donated_instructions,
|
||
&original_id_to_donated_id](
|
||
const opt::Instruction* instruction) {
|
||
// Get the instruction's input operands into donation-ready form,
|
||
// remapping any id uses in the process.
|
||
opt::Instruction::OperandList input_operands;
|
||
|
||
// Consider each input operand in turn.
|
||
for (uint32_t in_operand_index = 0;
|
||
in_operand_index < instruction->NumInOperands();
|
||
in_operand_index++) {
|
||
std::vector<uint32_t> operand_data;
|
||
const opt::Operand& in_operand =
|
||
instruction->GetInOperand(in_operand_index);
|
||
switch (in_operand.type) {
|
||
case SPV_OPERAND_TYPE_ID:
|
||
case SPV_OPERAND_TYPE_TYPE_ID:
|
||
case SPV_OPERAND_TYPE_RESULT_ID:
|
||
case SPV_OPERAND_TYPE_MEMORY_SEMANTICS_ID:
|
||
case SPV_OPERAND_TYPE_SCOPE_ID:
|
||
// This is an id operand - it consists of a single word of data,
|
||
// which needs to be remapped so that it is replaced with the
|
||
// donated form of the id.
|
||
operand_data.push_back(
|
||
original_id_to_donated_id->at(in_operand.words[0]));
|
||
break;
|
||
default:
|
||
// For non-id operands, we just add each of the data words.
|
||
for (auto word : in_operand.words) {
|
||
operand_data.push_back(word);
|
||
}
|
||
break;
|
||
}
|
||
input_operands.push_back({in_operand.type, operand_data});
|
||
}
|
||
|
||
if (instruction->opcode() == SpvOpVariable &&
|
||
instruction->NumInOperands() == 1) {
|
||
// This is an uninitialized local variable. Initialize it to zero.
|
||
input_operands.push_back(
|
||
{SPV_OPERAND_TYPE_ID,
|
||
{FindOrCreateZeroConstant(
|
||
fuzzerutil::GetPointeeTypeIdFromPointerType(
|
||
GetIRContext(),
|
||
original_id_to_donated_id->at(instruction->type_id())))}});
|
||
}
|
||
|
||
// Remap the result type and result id (if present) of the
|
||
// instruction, and turn it into a protobuf message.
|
||
donated_instructions.push_back(MakeInstructionMessage(
|
||
instruction->opcode(),
|
||
instruction->type_id()
|
||
? original_id_to_donated_id->at(instruction->type_id())
|
||
: 0,
|
||
instruction->result_id()
|
||
? original_id_to_donated_id->at(instruction->result_id())
|
||
: 0,
|
||
input_operands));
|
||
});
|
||
|
||
if (make_livesafe) {
|
||
// Various types and constants must be in place for a function to be made
|
||
// live-safe. Add them if not already present.
|
||
FindOrCreateBoolType(); // Needed for comparisons
|
||
FindOrCreatePointerTo32BitIntegerType(
|
||
false, SpvStorageClassFunction); // Needed for adding loop limiters
|
||
FindOrCreate32BitIntegerConstant(
|
||
0, false); // Needed for initializing loop limiters
|
||
FindOrCreate32BitIntegerConstant(
|
||
1, false); // Needed for incrementing loop limiters
|
||
|
||
// Get a fresh id for the variable that will be used as a loop limiter.
|
||
const uint32_t loop_limiter_variable_id =
|
||
GetFuzzerContext()->GetFreshId();
|
||
// Choose a random loop limit, and add the required constant to the
|
||
// module if not already there.
|
||
const uint32_t loop_limit = FindOrCreate32BitIntegerConstant(
|
||
GetFuzzerContext()->GetRandomLoopLimit(), false);
|
||
|
||
// Consider every loop header in the function to donate, and create a
|
||
// structure capturing the ids to be used for manipulating the loop
|
||
// limiter each time the loop is iterated.
|
||
std::vector<protobufs::LoopLimiterInfo> loop_limiters;
|
||
for (auto& block : *function_to_donate) {
|
||
if (block.IsLoopHeader()) {
|
||
protobufs::LoopLimiterInfo loop_limiter;
|
||
// Grab the loop header's id, mapped to its donated value.
|
||
loop_limiter.set_loop_header_id(
|
||
original_id_to_donated_id->at(block.id()));
|
||
// Get fresh ids that will be used to load the loop limiter, increment
|
||
// it, compare it with the loop limit, and an id for a new block that
|
||
// will contain the loop's original terminator.
|
||
loop_limiter.set_load_id(GetFuzzerContext()->GetFreshId());
|
||
loop_limiter.set_increment_id(GetFuzzerContext()->GetFreshId());
|
||
loop_limiter.set_compare_id(GetFuzzerContext()->GetFreshId());
|
||
loop_limiter.set_logical_op_id(GetFuzzerContext()->GetFreshId());
|
||
loop_limiters.emplace_back(loop_limiter);
|
||
}
|
||
}
|
||
|
||
// Consider every access chain in the function to donate, and create a
|
||
// structure containing the ids necessary to clamp the access chain
|
||
// indices to be in-bounds.
|
||
std::vector<protobufs::AccessChainClampingInfo>
|
||
access_chain_clamping_info;
|
||
for (auto& block : *function_to_donate) {
|
||
for (auto& inst : block) {
|
||
switch (inst.opcode()) {
|
||
case SpvOpAccessChain:
|
||
case SpvOpInBoundsAccessChain: {
|
||
protobufs::AccessChainClampingInfo clamping_info;
|
||
clamping_info.set_access_chain_id(
|
||
original_id_to_donated_id->at(inst.result_id()));
|
||
|
||
auto base_object = donor_ir_context->get_def_use_mgr()->GetDef(
|
||
inst.GetSingleWordInOperand(0));
|
||
assert(base_object && "The base object must exist.");
|
||
auto pointer_type = donor_ir_context->get_def_use_mgr()->GetDef(
|
||
base_object->type_id());
|
||
assert(pointer_type &&
|
||
pointer_type->opcode() == SpvOpTypePointer &&
|
||
"The base object must have pointer type.");
|
||
|
||
auto should_be_composite_type =
|
||
donor_ir_context->get_def_use_mgr()->GetDef(
|
||
pointer_type->GetSingleWordInOperand(1));
|
||
|
||
// Walk the access chain, creating fresh ids to facilitate
|
||
// clamping each index. For simplicity we do this for every
|
||
// index, even though constant indices will not end up being
|
||
// clamped.
|
||
for (uint32_t index = 1; index < inst.NumInOperands(); index++) {
|
||
auto compare_and_select_ids =
|
||
clamping_info.add_compare_and_select_ids();
|
||
compare_and_select_ids->set_first(
|
||
GetFuzzerContext()->GetFreshId());
|
||
compare_and_select_ids->set_second(
|
||
GetFuzzerContext()->GetFreshId());
|
||
|
||
// Get the bound for the component being indexed into.
|
||
uint32_t bound =
|
||
TransformationAddFunction::GetBoundForCompositeIndex(
|
||
donor_ir_context, *should_be_composite_type);
|
||
const uint32_t index_id = inst.GetSingleWordInOperand(index);
|
||
auto index_inst =
|
||
donor_ir_context->get_def_use_mgr()->GetDef(index_id);
|
||
auto index_type_inst =
|
||
donor_ir_context->get_def_use_mgr()->GetDef(
|
||
index_inst->type_id());
|
||
assert(index_type_inst->opcode() == SpvOpTypeInt);
|
||
assert(index_type_inst->GetSingleWordInOperand(0) == 32);
|
||
opt::analysis::Integer* index_int_type =
|
||
donor_ir_context->get_type_mgr()
|
||
->GetType(index_type_inst->result_id())
|
||
->AsInteger();
|
||
if (index_inst->opcode() != SpvOpConstant) {
|
||
// We will have to clamp this index, so we need a constant
|
||
// whose value is one less than the bound, to compare
|
||
// against and to use as the clamped value.
|
||
FindOrCreate32BitIntegerConstant(bound - 1,
|
||
index_int_type->IsSigned());
|
||
}
|
||
should_be_composite_type =
|
||
TransformationAddFunction::FollowCompositeIndex(
|
||
donor_ir_context, *should_be_composite_type, index_id);
|
||
}
|
||
access_chain_clamping_info.push_back(clamping_info);
|
||
break;
|
||
}
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
// If the function contains OpKill or OpUnreachable instructions, and has
|
||
// non-void return type, then we need a value %v to use in order to turn
|
||
// these into instructions of the form OpReturn %v.
|
||
uint32_t kill_unreachable_return_value_id;
|
||
auto function_return_type_inst =
|
||
donor_ir_context->get_def_use_mgr()->GetDef(
|
||
function_to_donate->type_id());
|
||
if (function_return_type_inst->opcode() == SpvOpTypeVoid) {
|
||
// The return type is void, so we don't need a return value.
|
||
kill_unreachable_return_value_id = 0;
|
||
} else {
|
||
// We do need a return value; we use zero.
|
||
assert(function_return_type_inst->opcode() != SpvOpTypePointer &&
|
||
"Function return type must not be a pointer.");
|
||
kill_unreachable_return_value_id =
|
||
FindOrCreateZeroConstant(original_id_to_donated_id->at(
|
||
function_return_type_inst->result_id()));
|
||
}
|
||
// Add the function in a livesafe manner.
|
||
ApplyTransformation(TransformationAddFunction(
|
||
donated_instructions, loop_limiter_variable_id, loop_limit,
|
||
loop_limiters, kill_unreachable_return_value_id,
|
||
access_chain_clamping_info));
|
||
} else {
|
||
// Add the function in a non-livesafe manner.
|
||
ApplyTransformation(TransformationAddFunction(donated_instructions));
|
||
}
|
||
}
|
||
}
|
||
|
||
std::vector<uint32_t>
|
||
FuzzerPassDonateModules::GetFunctionsInCallGraphTopologicalOrder(
|
||
opt::IRContext* context) {
|
||
CallGraph call_graph(context);
|
||
|
||
// This is an implementation of Kahn’s algorithm for topological sorting.
|
||
|
||
// This is the sorted order of function ids that we will eventually return.
|
||
std::vector<uint32_t> result;
|
||
|
||
// Get a copy of the initial in-degrees of all functions. The algorithm
|
||
// involves decrementing these values, hence why we work on a copy.
|
||
std::map<uint32_t, uint32_t> function_in_degree =
|
||
call_graph.GetFunctionInDegree();
|
||
|
||
// Populate a queue with all those function ids with in-degree zero.
|
||
std::queue<uint32_t> queue;
|
||
for (auto& entry : function_in_degree) {
|
||
if (entry.second == 0) {
|
||
queue.push(entry.first);
|
||
}
|
||
}
|
||
|
||
// Pop ids from the queue, adding them to the sorted order and decreasing the
|
||
// in-degrees of their successors. A successor who's in-degree becomes zero
|
||
// gets added to the queue.
|
||
while (!queue.empty()) {
|
||
auto next = queue.front();
|
||
queue.pop();
|
||
result.push_back(next);
|
||
for (auto successor : call_graph.GetDirectCallees(next)) {
|
||
assert(function_in_degree.at(successor) > 0 &&
|
||
"The in-degree cannot be zero if the function is a successor.");
|
||
function_in_degree[successor] = function_in_degree.at(successor) - 1;
|
||
if (function_in_degree.at(successor) == 0) {
|
||
queue.push(successor);
|
||
}
|
||
}
|
||
}
|
||
|
||
assert(result.size() == function_in_degree.size() &&
|
||
"Every function should appear in the sort.");
|
||
|
||
return result;
|
||
}
|
||
|
||
} // namespace fuzz
|
||
} // namespace spvtools
|