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// Copyright (c) 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/fuzz/transformation_replace_opphi_id_from_dead_predecessor.h"
#include "source/fuzz/fuzzer_util.h"
namespace spvtools {
namespace fuzz {
TransformationReplaceOpPhiIdFromDeadPredecessor::
TransformationReplaceOpPhiIdFromDeadPredecessor(
protobufs::TransformationReplaceOpPhiIdFromDeadPredecessor message)
: message_(std::move(message)) {}
TransformationReplaceOpPhiIdFromDeadPredecessor::
TransformationReplaceOpPhiIdFromDeadPredecessor(uint32_t opphi_id,
uint32_t pred_label_id,
uint32_t replacement_id) {
message_.set_opphi_id(opphi_id);
message_.set_pred_label_id(pred_label_id);
message_.set_replacement_id(replacement_id);
}
bool TransformationReplaceOpPhiIdFromDeadPredecessor::IsApplicable(
opt::IRContext* ir_context,
const TransformationContext& transformation_context) const {
// |opphi_id| must be the id of an OpPhi instruction.
auto opphi_def = ir_context->get_def_use_mgr()->GetDef(message_.opphi_id());
if (!opphi_def || opphi_def->opcode() != SpvOpPhi) {
return false;
}
// |pred_label_id| must be the label id of a dead block.
auto pred_block = ir_context->get_instr_block(message_.pred_label_id());
if (!pred_block || pred_block->id() != message_.pred_label_id() ||
!transformation_context.GetFactManager()->BlockIsDead(pred_block->id())) {
return false;
}
// |pred_label_id| must be one of the predecessors of the block containing the
// OpPhi instruction.
bool found = false;
for (auto pred :
ir_context->cfg()->preds(ir_context->get_instr_block(opphi_def)->id())) {
if (pred == message_.pred_label_id()) {
found = true;
break;
}
}
if (!found) {
return false;
}
// |replacement_id| must have the same type id as the OpPhi instruction.
auto replacement_def =
ir_context->get_def_use_mgr()->GetDef(message_.replacement_id());
if (!replacement_def || replacement_def->type_id() != opphi_def->type_id()) {
return false;
}
// The replacement id must be available at the end of the predecessor.
return fuzzerutil::IdIsAvailableBeforeInstruction(
ir_context, pred_block->terminator(), replacement_def->result_id());
}
void TransformationReplaceOpPhiIdFromDeadPredecessor::Apply(
opt::IRContext* ir_context,
TransformationContext* /* transformation_context */) const {
// Get the OpPhi instruction.
auto opphi_def = ir_context->get_def_use_mgr()->GetDef(message_.opphi_id());
// Find the index corresponding to the operand being replaced and replace it,
// by looping through the odd-indexed input operands and finding
// |pred_label_id|. The index that we are interested in is the one before
// that.
for (uint32_t i = 1; i < opphi_def->NumInOperands(); i += 2) {
if (opphi_def->GetSingleWordInOperand(i) == message_.pred_label_id()) {
// The operand to be replaced is at index i-1.
opphi_def->SetInOperand(i - 1, {message_.replacement_id()});
}
}
// Invalidate the analyses because we have altered the usages of ids.
ir_context->InvalidateAnalysesExceptFor(opt::IRContext::kAnalysisNone);
}
protobufs::Transformation
TransformationReplaceOpPhiIdFromDeadPredecessor::ToMessage() const {
protobufs::Transformation result;
*result.mutable_replace_opphi_id_from_dead_predecessor() = message_;
return result;
}
std::unordered_set<uint32_t>
TransformationReplaceOpPhiIdFromDeadPredecessor::GetFreshIds() const {
return std::unordered_set<uint32_t>();
}
} // namespace fuzz
} // namespace spvtools
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