SPIRV-Tools/source/fuzz/transformation_adjust_branch_weights.cpp
Alastair Donaldson fcb22ecf0f
spirv-fuzz: Report fresh ids in transformations (#3856)
Adds a virtual method, GetFreshIds(), to Transformation. Every
transformation uses this to indicate which ids in its protobuf message
are fresh ids. This means that when replaying a sequence of
transformations the replayer can obtain a smallest id that is not in
use by the module already and that will not be used by any
transformation by necessity. Ids greater than or equal to this id
can be used as overflow ids.

Fixes #3851.
2020-09-29 22:12:49 +01:00

103 lines
3.6 KiB
C++

// Copyright (c) 2020 André Perez Maselco
//
// 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_adjust_branch_weights.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
namespace spvtools {
namespace fuzz {
namespace {
const uint32_t kBranchWeightForTrueLabelIndex = 3;
const uint32_t kBranchWeightForFalseLabelIndex = 4;
} // namespace
TransformationAdjustBranchWeights::TransformationAdjustBranchWeights(
const spvtools::fuzz::protobufs::TransformationAdjustBranchWeights& message)
: message_(message) {}
TransformationAdjustBranchWeights::TransformationAdjustBranchWeights(
const protobufs::InstructionDescriptor& instruction_descriptor,
const std::pair<uint32_t, uint32_t>& branch_weights) {
*message_.mutable_instruction_descriptor() = instruction_descriptor;
message_.mutable_branch_weights()->set_first(branch_weights.first);
message_.mutable_branch_weights()->set_second(branch_weights.second);
}
bool TransformationAdjustBranchWeights::IsApplicable(
opt::IRContext* ir_context, const TransformationContext& /*unused*/) const {
auto instruction =
FindInstruction(message_.instruction_descriptor(), ir_context);
if (instruction == nullptr) {
return false;
}
SpvOp opcode = static_cast<SpvOp>(
message_.instruction_descriptor().target_instruction_opcode());
assert(instruction->opcode() == opcode &&
"The located instruction must have the same opcode as in the "
"descriptor.");
// Must be an OpBranchConditional instruction.
if (opcode != SpvOpBranchConditional) {
return false;
}
assert((message_.branch_weights().first() != 0 ||
message_.branch_weights().second() != 0) &&
"At least one weight must be non-zero.");
assert(message_.branch_weights().first() <=
UINT32_MAX - message_.branch_weights().second() &&
"The sum of the two weights must not be greater than UINT32_MAX.");
return true;
}
void TransformationAdjustBranchWeights::Apply(
opt::IRContext* ir_context, TransformationContext* /*unused*/) const {
auto instruction =
FindInstruction(message_.instruction_descriptor(), ir_context);
if (instruction->HasBranchWeights()) {
instruction->SetOperand(kBranchWeightForTrueLabelIndex,
{message_.branch_weights().first()});
instruction->SetOperand(kBranchWeightForFalseLabelIndex,
{message_.branch_weights().second()});
} else {
instruction->AddOperand({SPV_OPERAND_TYPE_OPTIONAL_LITERAL_INTEGER,
{message_.branch_weights().first()}});
instruction->AddOperand({SPV_OPERAND_TYPE_OPTIONAL_LITERAL_INTEGER,
{message_.branch_weights().second()}});
}
}
protobufs::Transformation TransformationAdjustBranchWeights::ToMessage() const {
protobufs::Transformation result;
*result.mutable_adjust_branch_weights() = message_;
return result;
}
std::unordered_set<uint32_t> TransformationAdjustBranchWeights::GetFreshIds()
const {
return std::unordered_set<uint32_t>();
}
} // namespace fuzz
} // namespace spvtools