SPIRV-Tools/source/fuzz/fuzzer_pass.cpp
alan-baker d35a78db57
Switch SPIRV-Tools to use spirv.hpp11 internally (#4981)
Fixes #4960

* Switches to using enum classes with an underlying type to avoid
  undefined behaviour
2022-11-04 17:27:10 -04:00

802 lines
31 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.h"
#include <set>
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/id_use_descriptor.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/transformation_add_constant_boolean.h"
#include "source/fuzz/transformation_add_constant_composite.h"
#include "source/fuzz/transformation_add_constant_null.h"
#include "source/fuzz/transformation_add_constant_scalar.h"
#include "source/fuzz/transformation_add_global_undef.h"
#include "source/fuzz/transformation_add_global_variable.h"
#include "source/fuzz/transformation_add_local_variable.h"
#include "source/fuzz/transformation_add_loop_preheader.h"
#include "source/fuzz/transformation_add_type_boolean.h"
#include "source/fuzz/transformation_add_type_float.h"
#include "source/fuzz/transformation_add_type_function.h"
#include "source/fuzz/transformation_add_type_int.h"
#include "source/fuzz/transformation_add_type_matrix.h"
#include "source/fuzz/transformation_add_type_pointer.h"
#include "source/fuzz/transformation_add_type_struct.h"
#include "source/fuzz/transformation_add_type_vector.h"
#include "source/fuzz/transformation_split_block.h"
namespace spvtools {
namespace fuzz {
FuzzerPass::FuzzerPass(opt::IRContext* ir_context,
TransformationContext* transformation_context,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations,
bool ignore_inapplicable_transformations)
: ir_context_(ir_context),
transformation_context_(transformation_context),
fuzzer_context_(fuzzer_context),
transformations_(transformations),
ignore_inapplicable_transformations_(
ignore_inapplicable_transformations) {}
FuzzerPass::~FuzzerPass() = default;
std::vector<opt::Instruction*> FuzzerPass::FindAvailableInstructions(
opt::Function* function, opt::BasicBlock* block,
const opt::BasicBlock::iterator& inst_it,
std::function<bool(opt::IRContext*, opt::Instruction*)>
instruction_is_relevant) const {
// TODO(afd) The following is (relatively) simple, but may end up being
// prohibitively inefficient, as it walks the whole dominator tree for
// every instruction that is considered.
std::vector<opt::Instruction*> result;
// Consider all global declarations
for (auto& global : GetIRContext()->module()->types_values()) {
if (instruction_is_relevant(GetIRContext(), &global)) {
result.push_back(&global);
}
}
// Consider all function parameters
function->ForEachParam(
[this, &instruction_is_relevant, &result](opt::Instruction* param) {
if (instruction_is_relevant(GetIRContext(), param)) {
result.push_back(param);
}
});
// Consider all previous instructions in this block
for (auto prev_inst_it = block->begin(); prev_inst_it != inst_it;
++prev_inst_it) {
if (instruction_is_relevant(GetIRContext(), &*prev_inst_it)) {
result.push_back(&*prev_inst_it);
}
}
// Walk the dominator tree to consider all instructions from dominating
// blocks
auto dominator_analysis = GetIRContext()->GetDominatorAnalysis(function);
for (auto next_dominator = dominator_analysis->ImmediateDominator(block);
next_dominator != nullptr;
next_dominator =
dominator_analysis->ImmediateDominator(next_dominator)) {
for (auto& dominating_inst : *next_dominator) {
if (instruction_is_relevant(GetIRContext(), &dominating_inst)) {
result.push_back(&dominating_inst);
}
}
}
return result;
}
void FuzzerPass::ForEachInstructionWithInstructionDescriptor(
opt::Function* function,
std::function<
void(opt::BasicBlock* block, opt::BasicBlock::iterator inst_it,
const protobufs::InstructionDescriptor& instruction_descriptor)>
action) {
// Consider only reachable blocks. We do this in a separate loop to avoid
// recomputing the dominator analysis every time |action| changes the
// module.
std::vector<opt::BasicBlock*> reachable_blocks;
for (auto& block : *function) {
if (GetIRContext()->IsReachable(block)) {
reachable_blocks.push_back(&block);
}
}
for (auto* block : reachable_blocks) {
// We now consider every instruction in the block, randomly deciding
// whether to apply a transformation before it.
// In order for transformations to insert new instructions, they need to
// be able to identify the instruction to insert before. We describe an
// instruction via its opcode, 'opc', a base instruction 'base' that has a
// result id, and the number of instructions with opcode 'opc' that we
// should skip when searching from 'base' for the desired instruction.
// (An instruction that has a result id is represented by its own opcode,
// itself as 'base', and a skip-count of 0.)
std::vector<std::tuple<uint32_t, spv::Op, uint32_t>>
base_opcode_skip_triples;
// The initial base instruction is the block label.
uint32_t base = block->id();
// Counts the number of times we have seen each opcode since we reset the
// base instruction.
std::map<spv::Op, uint32_t> skip_count;
// Consider every instruction in the block. The label is excluded: it is
// only necessary to consider it as a base in case the first instruction
// in the block does not have a result id.
for (auto inst_it = block->begin(); inst_it != block->end(); ++inst_it) {
if (inst_it->HasResultId()) {
// In the case that the instruction has a result id, we use the
// instruction as its own base, and clear the skip counts we have
// collected.
base = inst_it->result_id();
skip_count.clear();
}
const spv::Op opcode = inst_it->opcode();
// Invoke the provided function, which might apply a transformation.
action(block, inst_it,
MakeInstructionDescriptor(
base, opcode,
skip_count.count(opcode) ? skip_count.at(opcode) : 0));
if (!inst_it->HasResultId()) {
skip_count[opcode] =
skip_count.count(opcode) ? skip_count.at(opcode) + 1 : 1;
}
}
}
}
void FuzzerPass::ForEachInstructionWithInstructionDescriptor(
std::function<
void(opt::Function* function, opt::BasicBlock* block,
opt::BasicBlock::iterator inst_it,
const protobufs::InstructionDescriptor& instruction_descriptor)>
action) {
// Consider every block in every function.
for (auto& function : *GetIRContext()->module()) {
ForEachInstructionWithInstructionDescriptor(
&function,
[&action, &function](
opt::BasicBlock* block, opt::BasicBlock::iterator inst_it,
const protobufs::InstructionDescriptor& instruction_descriptor) {
action(&function, block, inst_it, instruction_descriptor);
});
}
}
void FuzzerPass::ApplyTransformation(const Transformation& transformation) {
if (ignore_inapplicable_transformations_) {
// If an applicable-by-construction transformation turns out to be
// inapplicable, this is a bug in the fuzzer. However, when deploying the
// fuzzer at scale for finding bugs in SPIR-V processing tools it is
// desirable to silently ignore such bugs. This code path caters for that
// scenario.
if (!transformation.IsApplicable(GetIRContext(),
*GetTransformationContext())) {
return;
}
} else {
// This code path caters for debugging bugs in the fuzzer, where an
// applicable-by-construction transformation turns out to be inapplicable.
assert(transformation.IsApplicable(GetIRContext(),
*GetTransformationContext()) &&
"Transformation should be applicable by construction.");
}
transformation.Apply(GetIRContext(), GetTransformationContext());
auto transformation_message = transformation.ToMessage();
assert(transformation_message.transformation_case() !=
protobufs::Transformation::TRANSFORMATION_NOT_SET &&
"Bad transformation.");
*GetTransformations()->add_transformation() =
std::move(transformation_message);
}
bool FuzzerPass::MaybeApplyTransformation(
const Transformation& transformation) {
if (transformation.IsApplicable(GetIRContext(),
*GetTransformationContext())) {
transformation.Apply(GetIRContext(), GetTransformationContext());
auto transformation_message = transformation.ToMessage();
assert(transformation_message.transformation_case() !=
protobufs::Transformation::TRANSFORMATION_NOT_SET &&
"Bad transformation.");
*GetTransformations()->add_transformation() =
std::move(transformation_message);
return true;
}
return false;
}
uint32_t FuzzerPass::FindOrCreateBoolType() {
if (auto existing_id = fuzzerutil::MaybeGetBoolType(GetIRContext())) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddTypeBoolean(result));
return result;
}
uint32_t FuzzerPass::FindOrCreateIntegerType(uint32_t width, bool is_signed) {
opt::analysis::Integer int_type(width, is_signed);
auto existing_id = GetIRContext()->get_type_mgr()->GetId(&int_type);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddTypeInt(result, width, is_signed));
return result;
}
uint32_t FuzzerPass::FindOrCreateFloatType(uint32_t width) {
opt::analysis::Float float_type(width);
auto existing_id = GetIRContext()->get_type_mgr()->GetId(&float_type);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddTypeFloat(result, width));
return result;
}
uint32_t FuzzerPass::FindOrCreateFunctionType(
uint32_t return_type_id, const std::vector<uint32_t>& argument_id) {
// FindFunctionType has a single argument for OpTypeFunction operands
// so we will have to copy them all in this vector
std::vector<uint32_t> type_ids(argument_id.size() + 1);
type_ids[0] = return_type_id;
std::copy(argument_id.begin(), argument_id.end(), type_ids.begin() + 1);
// Check if type exists
auto existing_id = fuzzerutil::FindFunctionType(GetIRContext(), type_ids);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(
TransformationAddTypeFunction(result, return_type_id, argument_id));
return result;
}
uint32_t FuzzerPass::FindOrCreateVectorType(uint32_t component_type_id,
uint32_t component_count) {
assert(component_count >= 2 && component_count <= 4 &&
"Precondition: component count must be in range [2, 4].");
opt::analysis::Type* component_type =
GetIRContext()->get_type_mgr()->GetType(component_type_id);
assert(component_type && "Precondition: the component type must exist.");
opt::analysis::Vector vector_type(component_type, component_count);
auto existing_id = GetIRContext()->get_type_mgr()->GetId(&vector_type);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(
TransformationAddTypeVector(result, component_type_id, component_count));
return result;
}
uint32_t FuzzerPass::FindOrCreateMatrixType(uint32_t column_count,
uint32_t row_count) {
assert(column_count >= 2 && column_count <= 4 &&
"Precondition: column count must be in range [2, 4].");
assert(row_count >= 2 && row_count <= 4 &&
"Precondition: row count must be in range [2, 4].");
uint32_t column_type_id =
FindOrCreateVectorType(FindOrCreateFloatType(32), row_count);
opt::analysis::Type* column_type =
GetIRContext()->get_type_mgr()->GetType(column_type_id);
opt::analysis::Matrix matrix_type(column_type, column_count);
auto existing_id = GetIRContext()->get_type_mgr()->GetId(&matrix_type);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(
TransformationAddTypeMatrix(result, column_type_id, column_count));
return result;
}
uint32_t FuzzerPass::FindOrCreateStructType(
const std::vector<uint32_t>& component_type_ids) {
if (auto existing_id =
fuzzerutil::MaybeGetStructType(GetIRContext(), component_type_ids)) {
return existing_id;
}
auto new_id = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddTypeStruct(new_id, component_type_ids));
return new_id;
}
uint32_t FuzzerPass::FindOrCreatePointerType(uint32_t base_type_id,
spv::StorageClass storage_class) {
// We do not use the type manager here, due to problems related to isomorphic
// but distinct structs not being regarded as different.
auto existing_id = fuzzerutil::MaybeGetPointerType(
GetIRContext(), base_type_id, storage_class);
if (existing_id) {
return existing_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(
TransformationAddTypePointer(result, storage_class, base_type_id));
return result;
}
uint32_t FuzzerPass::FindOrCreatePointerToIntegerType(
uint32_t width, bool is_signed, spv::StorageClass storage_class) {
return FindOrCreatePointerType(FindOrCreateIntegerType(width, is_signed),
storage_class);
}
uint32_t FuzzerPass::FindOrCreateIntegerConstant(
const std::vector<uint32_t>& words, uint32_t width, bool is_signed,
bool is_irrelevant) {
auto int_type_id = FindOrCreateIntegerType(width, is_signed);
if (auto constant_id = fuzzerutil::MaybeGetScalarConstant(
GetIRContext(), *GetTransformationContext(), words, int_type_id,
is_irrelevant)) {
return constant_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddConstantScalar(result, int_type_id,
words, is_irrelevant));
return result;
}
uint32_t FuzzerPass::FindOrCreateFloatConstant(
const std::vector<uint32_t>& words, uint32_t width, bool is_irrelevant) {
auto float_type_id = FindOrCreateFloatType(width);
if (auto constant_id = fuzzerutil::MaybeGetScalarConstant(
GetIRContext(), *GetTransformationContext(), words, float_type_id,
is_irrelevant)) {
return constant_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddConstantScalar(result, float_type_id,
words, is_irrelevant));
return result;
}
uint32_t FuzzerPass::FindOrCreateBoolConstant(bool value, bool is_irrelevant) {
auto bool_type_id = FindOrCreateBoolType();
if (auto constant_id = fuzzerutil::MaybeGetScalarConstant(
GetIRContext(), *GetTransformationContext(), {value ? 1u : 0u},
bool_type_id, is_irrelevant)) {
return constant_id;
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(
TransformationAddConstantBoolean(result, value, is_irrelevant));
return result;
}
uint32_t FuzzerPass::FindOrCreateConstant(const std::vector<uint32_t>& words,
uint32_t type_id,
bool is_irrelevant) {
assert(type_id && "Constant's type id can't be 0.");
const auto* type = GetIRContext()->get_type_mgr()->GetType(type_id);
assert(type && "Type does not exist.");
if (type->AsBool()) {
assert(words.size() == 1);
return FindOrCreateBoolConstant(words[0], is_irrelevant);
} else if (const auto* integer = type->AsInteger()) {
return FindOrCreateIntegerConstant(words, integer->width(),
integer->IsSigned(), is_irrelevant);
} else if (const auto* floating = type->AsFloat()) {
return FindOrCreateFloatConstant(words, floating->width(), is_irrelevant);
}
// This assertion will fail in debug build but not in release build
// so we return 0 to make compiler happy.
assert(false && "Constant type is not supported");
return 0;
}
uint32_t FuzzerPass::FindOrCreateCompositeConstant(
const std::vector<uint32_t>& component_ids, uint32_t type_id,
bool is_irrelevant) {
if (auto existing_constant = fuzzerutil::MaybeGetCompositeConstant(
GetIRContext(), *GetTransformationContext(), component_ids, type_id,
is_irrelevant)) {
return existing_constant;
}
uint32_t result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddConstantComposite(
result, type_id, component_ids, is_irrelevant));
return result;
}
uint32_t FuzzerPass::FindOrCreateGlobalUndef(uint32_t type_id) {
for (auto& inst : GetIRContext()->types_values()) {
if (inst.opcode() == spv::Op::OpUndef && inst.type_id() == type_id) {
return inst.result_id();
}
}
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddGlobalUndef(result, type_id));
return result;
}
uint32_t FuzzerPass::FindOrCreateNullConstant(uint32_t type_id) {
// Find existing declaration
opt::analysis::NullConstant null_constant(
GetIRContext()->get_type_mgr()->GetType(type_id));
auto existing_constant =
GetIRContext()->get_constant_mgr()->FindConstant(&null_constant);
// Return if found
if (existing_constant) {
return GetIRContext()
->get_constant_mgr()
->GetDefiningInstruction(existing_constant)
->result_id();
}
// Create new if not found
auto result = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddConstantNull(result, type_id));
return result;
}
std::pair<std::vector<uint32_t>, std::map<uint32_t, std::vector<uint32_t>>>
FuzzerPass::GetAvailableBasicTypesAndPointers(
spv::StorageClass storage_class) const {
// Records all of the basic types available in the module.
std::set<uint32_t> basic_types;
// For each basic type, records all the associated pointer types that target
// the basic type and that have |storage_class| as their storage class.
std::map<uint32_t, std::vector<uint32_t>> basic_type_to_pointers;
for (auto& inst : GetIRContext()->types_values()) {
// For each basic type that we come across, record type, and the fact that
// we cannot yet have seen any pointers that use the basic type as its
// pointee type.
//
// For pointer types with basic pointee types, associate the pointer type
// with the basic type.
switch (inst.opcode()) {
case spv::Op::OpTypeBool:
case spv::Op::OpTypeFloat:
case spv::Op::OpTypeInt:
case spv::Op::OpTypeMatrix:
case spv::Op::OpTypeVector:
// These are all basic types.
basic_types.insert(inst.result_id());
basic_type_to_pointers.insert({inst.result_id(), {}});
break;
case spv::Op::OpTypeArray:
// An array type is basic if its base type is basic.
if (basic_types.count(inst.GetSingleWordInOperand(0))) {
basic_types.insert(inst.result_id());
basic_type_to_pointers.insert({inst.result_id(), {}});
}
break;
case spv::Op::OpTypeStruct: {
// A struct type is basic if it does not have the Block/BufferBlock
// decoration, and if all of its members are basic.
if (!fuzzerutil::HasBlockOrBufferBlockDecoration(GetIRContext(),
inst.result_id())) {
bool all_members_are_basic_types = true;
for (uint32_t i = 0; i < inst.NumInOperands(); i++) {
if (!basic_types.count(inst.GetSingleWordInOperand(i))) {
all_members_are_basic_types = false;
break;
}
}
if (all_members_are_basic_types) {
basic_types.insert(inst.result_id());
basic_type_to_pointers.insert({inst.result_id(), {}});
}
}
break;
}
case spv::Op::OpTypePointer: {
// We are interested in the pointer if its pointee type is basic and it
// has the right storage class.
auto pointee_type = inst.GetSingleWordInOperand(1);
if (spv::StorageClass(inst.GetSingleWordInOperand(0)) ==
storage_class &&
basic_types.count(pointee_type)) {
// The pointer has the desired storage class, and its pointee type is
// a basic type, so we are interested in it. Associate it with its
// basic type.
basic_type_to_pointers.at(pointee_type).push_back(inst.result_id());
}
break;
}
default:
break;
}
}
return {{basic_types.begin(), basic_types.end()}, basic_type_to_pointers};
}
uint32_t FuzzerPass::FindOrCreateZeroConstant(
uint32_t scalar_or_composite_type_id, bool is_irrelevant) {
auto type_instruction =
GetIRContext()->get_def_use_mgr()->GetDef(scalar_or_composite_type_id);
assert(type_instruction && "The type instruction must exist.");
switch (type_instruction->opcode()) {
case spv::Op::OpTypeBool:
return FindOrCreateBoolConstant(false, is_irrelevant);
case spv::Op::OpTypeFloat: {
auto width = type_instruction->GetSingleWordInOperand(0);
auto num_words = (width + 32 - 1) / 32;
return FindOrCreateFloatConstant(std::vector<uint32_t>(num_words, 0),
width, is_irrelevant);
}
case spv::Op::OpTypeInt: {
auto width = type_instruction->GetSingleWordInOperand(0);
auto num_words = (width + 32 - 1) / 32;
return FindOrCreateIntegerConstant(
std::vector<uint32_t>(num_words, 0), width,
type_instruction->GetSingleWordInOperand(1), is_irrelevant);
}
case spv::Op::OpTypeArray: {
auto component_type_id = type_instruction->GetSingleWordInOperand(0);
auto num_components =
fuzzerutil::GetArraySize(*type_instruction, GetIRContext());
return FindOrCreateCompositeConstant(
std::vector<uint32_t>(
num_components,
FindOrCreateZeroConstant(component_type_id, is_irrelevant)),
scalar_or_composite_type_id, is_irrelevant);
}
case spv::Op::OpTypeMatrix:
case spv::Op::OpTypeVector: {
auto component_type_id = type_instruction->GetSingleWordInOperand(0);
auto num_components = type_instruction->GetSingleWordInOperand(1);
return FindOrCreateCompositeConstant(
std::vector<uint32_t>(
num_components,
FindOrCreateZeroConstant(component_type_id, is_irrelevant)),
scalar_or_composite_type_id, is_irrelevant);
}
case spv::Op::OpTypeStruct: {
assert(!fuzzerutil::HasBlockOrBufferBlockDecoration(
GetIRContext(), scalar_or_composite_type_id) &&
"We do not construct constants of struct types decorated with "
"Block or BufferBlock.");
std::vector<uint32_t> field_zero_ids;
for (uint32_t index = 0; index < type_instruction->NumInOperands();
index++) {
field_zero_ids.push_back(FindOrCreateZeroConstant(
type_instruction->GetSingleWordInOperand(index), is_irrelevant));
}
return FindOrCreateCompositeConstant(
field_zero_ids, scalar_or_composite_type_id, is_irrelevant);
}
default:
assert(false && "Unknown type.");
return 0;
}
}
void FuzzerPass::MaybeAddUseToReplace(
opt::Instruction* use_inst, uint32_t use_index, uint32_t replacement_id,
std::vector<std::pair<protobufs::IdUseDescriptor, uint32_t>>*
uses_to_replace) {
// Only consider this use if it is in a block
if (!GetIRContext()->get_instr_block(use_inst)) {
return;
}
// Get the index of the operand restricted to input operands.
uint32_t in_operand_index =
fuzzerutil::InOperandIndexFromOperandIndex(*use_inst, use_index);
auto id_use_descriptor =
MakeIdUseDescriptorFromUse(GetIRContext(), use_inst, in_operand_index);
uses_to_replace->emplace_back(
std::make_pair(id_use_descriptor, replacement_id));
}
opt::BasicBlock* FuzzerPass::GetOrCreateSimpleLoopPreheader(
uint32_t header_id) {
auto header_block = fuzzerutil::MaybeFindBlock(GetIRContext(), header_id);
assert(header_block && header_block->IsLoopHeader() &&
"|header_id| should be the label id of a loop header");
auto predecessors = GetIRContext()->cfg()->preds(header_id);
assert(predecessors.size() >= 2 &&
"The block |header_id| should be reachable.");
auto function = header_block->GetParent();
if (predecessors.size() == 2) {
// The header has a single out-of-loop predecessor, which could be a
// preheader.
opt::BasicBlock* maybe_preheader;
if (GetIRContext()->GetDominatorAnalysis(function)->Dominates(
header_id, predecessors[0])) {
// The first predecessor is the back-edge block, because the header
// dominates it, so the second one is out of the loop.
maybe_preheader = &*function->FindBlock(predecessors[1]);
} else {
// The first predecessor is out of the loop.
maybe_preheader = &*function->FindBlock(predecessors[0]);
}
// |maybe_preheader| is a preheader if it branches unconditionally to
// the header. We also require it not to be a loop header.
if (maybe_preheader->terminator()->opcode() == spv::Op::OpBranch &&
!maybe_preheader->IsLoopHeader()) {
return maybe_preheader;
}
}
// We need to add a preheader.
// Get a fresh id for the preheader.
uint32_t preheader_id = GetFuzzerContext()->GetFreshId();
// Get a fresh id for each OpPhi instruction, if there is more than one
// out-of-loop predecessor.
std::vector<uint32_t> phi_ids;
if (predecessors.size() > 2) {
header_block->ForEachPhiInst(
[this, &phi_ids](opt::Instruction* /* unused */) {
phi_ids.push_back(GetFuzzerContext()->GetFreshId());
});
}
// Add the preheader.
ApplyTransformation(
TransformationAddLoopPreheader(header_id, preheader_id, phi_ids));
// Make the newly-created preheader the new entry block.
return &*function->FindBlock(preheader_id);
}
opt::BasicBlock* FuzzerPass::SplitBlockAfterOpPhiOrOpVariable(
uint32_t block_id) {
auto block = fuzzerutil::MaybeFindBlock(GetIRContext(), block_id);
assert(block && "|block_id| must be a block label");
assert(!block->IsLoopHeader() && "|block_id| cannot be a loop header");
// Find the first non-OpPhi and non-OpVariable instruction.
auto non_phi_or_var_inst = &*block->begin();
while (non_phi_or_var_inst->opcode() == spv::Op::OpPhi ||
non_phi_or_var_inst->opcode() == spv::Op::OpVariable) {
non_phi_or_var_inst = non_phi_or_var_inst->NextNode();
}
// Split the block.
uint32_t new_block_id = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationSplitBlock(
MakeInstructionDescriptor(GetIRContext(), non_phi_or_var_inst),
new_block_id));
// We need to return the newly-created block.
return &*block->GetParent()->FindBlock(new_block_id);
}
uint32_t FuzzerPass::FindOrCreateLocalVariable(
uint32_t pointer_type_id, uint32_t function_id,
bool pointee_value_is_irrelevant) {
auto pointer_type = GetIRContext()->get_type_mgr()->GetType(pointer_type_id);
// No unused variables in release mode.
(void)pointer_type;
assert(pointer_type && pointer_type->AsPointer() &&
pointer_type->AsPointer()->storage_class() ==
spv::StorageClass::Function &&
"The pointer_type_id must refer to a defined pointer type with "
"storage class Function");
auto function = fuzzerutil::FindFunction(GetIRContext(), function_id);
assert(function && "The function must be defined.");
// First we try to find a suitable existing variable.
// All of the local variable declarations are located in the first block.
for (auto& instruction : *function->begin()) {
if (instruction.opcode() != spv::Op::OpVariable) {
continue;
}
// The existing OpVariable must have type |pointer_type_id|.
if (instruction.type_id() != pointer_type_id) {
continue;
}
// Check if the found variable is marked with PointeeValueIsIrrelevant
// according to |pointee_value_is_irrelevant|.
if (GetTransformationContext()->GetFactManager()->PointeeValueIsIrrelevant(
instruction.result_id()) != pointee_value_is_irrelevant) {
continue;
}
return instruction.result_id();
}
// No such variable was found. Apply a transformation to get one.
uint32_t pointee_type_id = fuzzerutil::GetPointeeTypeIdFromPointerType(
GetIRContext(), pointer_type_id);
uint32_t result_id = GetFuzzerContext()->GetFreshId();
ApplyTransformation(TransformationAddLocalVariable(
result_id, pointer_type_id, function_id,
FindOrCreateZeroConstant(pointee_type_id, pointee_value_is_irrelevant),
pointee_value_is_irrelevant));
return result_id;
}
uint32_t FuzzerPass::FindOrCreateGlobalVariable(
uint32_t pointer_type_id, bool pointee_value_is_irrelevant) {
auto pointer_type = GetIRContext()->get_type_mgr()->GetType(pointer_type_id);
// No unused variables in release mode.
(void)pointer_type;
assert(
pointer_type && pointer_type->AsPointer() &&
(pointer_type->AsPointer()->storage_class() ==
spv::StorageClass::Private ||
pointer_type->AsPointer()->storage_class() ==
spv::StorageClass::Workgroup) &&
"The pointer_type_id must refer to a defined pointer type with storage "
"class Private or Workgroup");
// First we try to find a suitable existing variable.
for (auto& instruction : GetIRContext()->module()->types_values()) {
if (instruction.opcode() != spv::Op::OpVariable) {
continue;
}
// The existing OpVariable must have type |pointer_type_id|.
if (instruction.type_id() != pointer_type_id) {
continue;
}
// Check if the found variable is marked with PointeeValueIsIrrelevant
// according to |pointee_value_is_irrelevant|.
if (GetTransformationContext()->GetFactManager()->PointeeValueIsIrrelevant(
instruction.result_id()) != pointee_value_is_irrelevant) {
continue;
}
return instruction.result_id();
}
// No such variable was found. Apply a transformation to get one.
uint32_t pointee_type_id = fuzzerutil::GetPointeeTypeIdFromPointerType(
GetIRContext(), pointer_type_id);
auto storage_class = fuzzerutil::GetStorageClassFromPointerType(
GetIRContext(), pointer_type_id);
uint32_t result_id = GetFuzzerContext()->GetFreshId();
// A variable with storage class Workgroup shouldn't have an initializer.
if (storage_class == spv::StorageClass::Workgroup) {
ApplyTransformation(TransformationAddGlobalVariable(
result_id, pointer_type_id, spv::StorageClass::Workgroup, 0,
pointee_value_is_irrelevant));
} else {
ApplyTransformation(TransformationAddGlobalVariable(
result_id, pointer_type_id, spv::StorageClass::Private,
FindOrCreateZeroConstant(pointee_type_id, pointee_value_is_irrelevant),
pointee_value_is_irrelevant));
}
return result_id;
}
} // namespace fuzz
} // namespace spvtools