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https://github.com/KhronosGroup/SPIRV-Tools
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f278b467df
The outliner would outline regions ending with a loop header, making the block containing the call to the outlined function serve as the loop header. This, however, is incorrect in general, since the whole outlined function -- rather than just the exit block for the region -- would end up getting called every time the loop would iterate. This change restricts the outliner so that the last block in a region cannot be a loop header.
968 lines
40 KiB
C++
968 lines
40 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/transformation_outline_function.h"
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#include <set>
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#include "source/fuzz/fuzzer_util.h"
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namespace spvtools {
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namespace fuzz {
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namespace {
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std::map<uint32_t, uint32_t> PairSequenceToMap(
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const google::protobuf::RepeatedPtrField<protobufs::UInt32Pair>&
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pair_sequence) {
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std::map<uint32_t, uint32_t> result;
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for (auto& pair : pair_sequence) {
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result[pair.first()] = pair.second();
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}
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return result;
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}
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} // namespace
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TransformationOutlineFunction::TransformationOutlineFunction(
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const spvtools::fuzz::protobufs::TransformationOutlineFunction& message)
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: message_(message) {}
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TransformationOutlineFunction::TransformationOutlineFunction(
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uint32_t entry_block, uint32_t exit_block,
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uint32_t new_function_struct_return_type_id, uint32_t new_function_type_id,
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uint32_t new_function_id, uint32_t new_function_region_entry_block,
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uint32_t new_caller_result_id, uint32_t new_callee_result_id,
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std::map<uint32_t, uint32_t>&& input_id_to_fresh_id,
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std::map<uint32_t, uint32_t>&& output_id_to_fresh_id) {
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message_.set_entry_block(entry_block);
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message_.set_exit_block(exit_block);
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message_.set_new_function_struct_return_type_id(
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new_function_struct_return_type_id);
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message_.set_new_function_type_id(new_function_type_id);
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message_.set_new_function_id(new_function_id);
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message_.set_new_function_region_entry_block(new_function_region_entry_block);
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message_.set_new_caller_result_id(new_caller_result_id);
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message_.set_new_callee_result_id(new_callee_result_id);
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for (auto& entry : input_id_to_fresh_id) {
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protobufs::UInt32Pair pair;
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pair.set_first(entry.first);
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pair.set_second(entry.second);
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*message_.add_input_id_to_fresh_id() = pair;
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}
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for (auto& entry : output_id_to_fresh_id) {
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protobufs::UInt32Pair pair;
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pair.set_first(entry.first);
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pair.set_second(entry.second);
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*message_.add_output_id_to_fresh_id() = pair;
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}
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}
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bool TransformationOutlineFunction::IsApplicable(
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opt::IRContext* ir_context, const TransformationContext& /*unused*/) const {
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std::set<uint32_t> ids_used_by_this_transformation;
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// The various new ids used by the transformation must be fresh and distinct.
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_function_struct_return_type_id(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_function_type_id(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_function_id(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_function_region_entry_block(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_caller_result_id(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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message_.new_callee_result_id(), ir_context,
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&ids_used_by_this_transformation)) {
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return false;
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}
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for (auto& pair : message_.input_id_to_fresh_id()) {
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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pair.second(), ir_context, &ids_used_by_this_transformation)) {
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return false;
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}
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}
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for (auto& pair : message_.output_id_to_fresh_id()) {
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if (!CheckIdIsFreshAndNotUsedByThisTransformation(
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pair.second(), ir_context, &ids_used_by_this_transformation)) {
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return false;
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}
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}
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// The entry and exit block ids must indeed refer to blocks.
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for (auto block_id : {message_.entry_block(), message_.exit_block()}) {
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auto block_label = ir_context->get_def_use_mgr()->GetDef(block_id);
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if (!block_label || block_label->opcode() != SpvOpLabel) {
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return false;
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}
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}
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auto entry_block = ir_context->cfg()->block(message_.entry_block());
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auto exit_block = ir_context->cfg()->block(message_.exit_block());
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// The entry block cannot start with OpVariable - this would mean that
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// outlining would remove a variable from the function containing the region
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// being outlined.
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if (entry_block->begin()->opcode() == SpvOpVariable) {
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return false;
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}
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// For simplicity, we do not allow the entry block to be a loop header.
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if (entry_block->GetLoopMergeInst()) {
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return false;
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}
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// For simplicity, we do not allow the exit block to be a merge block or
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// continue target.
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if (fuzzerutil::IsMergeOrContinue(ir_context, exit_block->id())) {
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return false;
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}
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// The entry block cannot start with OpPhi. This is to keep the
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// transformation logic simple. (Another transformation to split the OpPhis
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// from a block could be applied to avoid this scenario.)
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if (entry_block->begin()->opcode() == SpvOpPhi) {
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return false;
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}
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// The block must be in the same function.
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if (entry_block->GetParent() != exit_block->GetParent()) {
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return false;
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}
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// The entry block must dominate the exit block.
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auto dominator_analysis =
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ir_context->GetDominatorAnalysis(entry_block->GetParent());
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if (!dominator_analysis->Dominates(entry_block, exit_block)) {
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return false;
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}
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// The exit block must post-dominate the entry block.
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auto postdominator_analysis =
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ir_context->GetPostDominatorAnalysis(entry_block->GetParent());
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if (!postdominator_analysis->Dominates(exit_block, entry_block)) {
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return false;
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}
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// Find all the blocks dominated by |message_.entry_block| and post-dominated
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// by |message_.exit_block|.
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auto region_set = GetRegionBlocks(
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ir_context,
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entry_block = ir_context->cfg()->block(message_.entry_block()),
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exit_block = ir_context->cfg()->block(message_.exit_block()));
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// Check whether |region_set| really is a single-entry single-exit region, and
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// also check whether structured control flow constructs and their merge
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// and continue constructs are either wholly in or wholly out of the region -
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// e.g. avoid the situation where the region contains the head of a loop but
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// not the loop's continue construct.
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//
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// This is achieved by going through every block in the function that contains
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// the region.
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for (auto& block : *entry_block->GetParent()) {
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if (&block == exit_block) {
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// It is OK (and typically expected) for the exit block of the region to
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// have successors outside the region.
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//
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// It is also OK for the exit block to head a selection construct: the
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// block containing the call to the outlined function will end up heading
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// this construct if outlining takes place. However, it is not OK for
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// the exit block to head a loop construct.
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if (block.GetLoopMergeInst()) {
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return false;
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}
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continue;
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}
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if (region_set.count(&block) != 0) {
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// The block is in the region and is not the region's exit block. Let's
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// see whether all of the block's successors are in the region. If they
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// are not, the region is not single-entry single-exit.
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bool all_successors_in_region = true;
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block.WhileEachSuccessorLabel([&all_successors_in_region, ir_context,
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®ion_set](uint32_t successor) -> bool {
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if (region_set.count(ir_context->cfg()->block(successor)) == 0) {
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all_successors_in_region = false;
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return false;
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}
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return true;
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});
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if (!all_successors_in_region) {
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return false;
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}
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}
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if (auto merge = block.GetMergeInst()) {
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// The block is a loop or selection header -- the header and its
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// associated merge block had better both be in the region or both be
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// outside the region.
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auto merge_block =
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ir_context->cfg()->block(merge->GetSingleWordOperand(0));
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if (region_set.count(&block) != region_set.count(merge_block)) {
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return false;
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}
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}
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if (auto loop_merge = block.GetLoopMergeInst()) {
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// Similar to the above, but for the continue target of a loop.
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auto continue_target =
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ir_context->cfg()->block(loop_merge->GetSingleWordOperand(1));
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if (continue_target != exit_block &&
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region_set.count(&block) != region_set.count(continue_target)) {
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return false;
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}
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}
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}
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// For each region input id, i.e. every id defined outside the region but
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// used inside the region, ...
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std::map<uint32_t, uint32_t> input_id_to_fresh_id_map =
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PairSequenceToMap(message_.input_id_to_fresh_id());
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for (auto id : GetRegionInputIds(ir_context, region_set, exit_block)) {
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// There needs to be a corresponding fresh id to be used as a function
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// parameter.
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if (input_id_to_fresh_id_map.count(id) == 0) {
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return false;
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}
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// Furthermore, if the input id has pointer type it must be an OpVariable
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// or OpFunctionParameter.
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auto input_id_inst = ir_context->get_def_use_mgr()->GetDef(id);
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if (ir_context->get_def_use_mgr()
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->GetDef(input_id_inst->type_id())
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->opcode() == SpvOpTypePointer) {
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switch (input_id_inst->opcode()) {
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case SpvOpFunctionParameter:
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case SpvOpVariable:
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// These are OK.
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break;
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default:
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// Anything else is not OK.
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return false;
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}
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}
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}
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// For each region output id -- i.e. every id defined inside the region but
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// used outside the region, ...
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std::map<uint32_t, uint32_t> output_id_to_fresh_id_map =
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PairSequenceToMap(message_.output_id_to_fresh_id());
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for (auto id : GetRegionOutputIds(ir_context, region_set, exit_block)) {
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if (
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// ... there needs to be a corresponding fresh id that can hold the
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// value for this id computed in the outlined function, and ...
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output_id_to_fresh_id_map.count(id) == 0
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// ... the output id must not have pointer type (to avoid creating a
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// struct with pointer members to pass data out of the outlined
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// function)
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|| ir_context->get_def_use_mgr()
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->GetDef(fuzzerutil::GetTypeId(ir_context, id))
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->opcode() == SpvOpTypePointer) {
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return false;
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}
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}
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return true;
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}
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void TransformationOutlineFunction::Apply(
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opt::IRContext* ir_context,
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TransformationContext* transformation_context) const {
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// The entry block for the region before outlining.
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auto original_region_entry_block =
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ir_context->cfg()->block(message_.entry_block());
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// The exit block for the region before outlining.
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auto original_region_exit_block =
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ir_context->cfg()->block(message_.exit_block());
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// The single-entry single-exit region defined by |message_.entry_block| and
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// |message_.exit_block|.
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std::set<opt::BasicBlock*> region_blocks = GetRegionBlocks(
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ir_context, original_region_entry_block, original_region_exit_block);
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// Input and output ids for the region being outlined.
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std::vector<uint32_t> region_input_ids =
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GetRegionInputIds(ir_context, region_blocks, original_region_exit_block);
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std::vector<uint32_t> region_output_ids =
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GetRegionOutputIds(ir_context, region_blocks, original_region_exit_block);
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// Maps from input and output ids to fresh ids.
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std::map<uint32_t, uint32_t> input_id_to_fresh_id_map =
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PairSequenceToMap(message_.input_id_to_fresh_id());
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std::map<uint32_t, uint32_t> output_id_to_fresh_id_map =
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PairSequenceToMap(message_.output_id_to_fresh_id());
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UpdateModuleIdBoundForFreshIds(ir_context, input_id_to_fresh_id_map,
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output_id_to_fresh_id_map);
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// Construct a map that associates each output id with its type id.
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std::map<uint32_t, uint32_t> output_id_to_type_id;
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for (uint32_t output_id : region_output_ids) {
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output_id_to_type_id[output_id] =
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ir_context->get_def_use_mgr()->GetDef(output_id)->type_id();
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}
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// The region will be collapsed to a single block that calls a function
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// containing the outlined region. This block needs to end with whatever
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// the exit block of the region ended with before outlining. We thus clone
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// the terminator of the region's exit block, and the merge instruction for
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// the block if there is one, so that we can append them to the end of the
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// collapsed block later.
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std::unique_ptr<opt::Instruction> cloned_exit_block_terminator =
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std::unique_ptr<opt::Instruction>(
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original_region_exit_block->terminator()->Clone(ir_context));
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std::unique_ptr<opt::Instruction> cloned_exit_block_merge =
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original_region_exit_block->GetMergeInst()
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? std::unique_ptr<opt::Instruction>(
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original_region_exit_block->GetMergeInst()->Clone(ir_context))
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: nullptr;
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// Make a function prototype for the outlined function, which involves
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// figuring out its required type.
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std::unique_ptr<opt::Function> outlined_function = PrepareFunctionPrototype(
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region_input_ids, region_output_ids, input_id_to_fresh_id_map, ir_context,
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transformation_context);
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// If the original function was livesafe, the new function should also be
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// livesafe.
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if (transformation_context->GetFactManager()->FunctionIsLivesafe(
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original_region_entry_block->GetParent()->result_id())) {
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transformation_context->GetFactManager()->AddFactFunctionIsLivesafe(
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message_.new_function_id());
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}
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// Adapt the region to be outlined so that its input ids are replaced with the
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// ids of the outlined function's input parameters, and so that output ids
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// are similarly remapped.
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RemapInputAndOutputIdsInRegion(
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ir_context, *original_region_exit_block, region_blocks, region_input_ids,
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region_output_ids, input_id_to_fresh_id_map, output_id_to_fresh_id_map);
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// Fill out the body of the outlined function according to the region that is
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// being outlined.
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PopulateOutlinedFunction(
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*original_region_entry_block, *original_region_exit_block, region_blocks,
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region_output_ids, output_id_to_fresh_id_map, ir_context,
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outlined_function.get(), transformation_context);
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// Collapse the region that has been outlined into a function down to a single
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// block that calls said function.
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ShrinkOriginalRegion(
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ir_context, region_blocks, region_input_ids, region_output_ids,
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output_id_to_type_id, outlined_function->type_id(),
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std::move(cloned_exit_block_merge),
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std::move(cloned_exit_block_terminator), original_region_entry_block);
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// Add the outlined function to the module.
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ir_context->module()->AddFunction(std::move(outlined_function));
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// Major surgery has been conducted on the module, so invalidate all analyses.
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ir_context->InvalidateAnalysesExceptFor(
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opt::IRContext::Analysis::kAnalysisNone);
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}
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protobufs::Transformation TransformationOutlineFunction::ToMessage() const {
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protobufs::Transformation result;
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*result.mutable_outline_function() = message_;
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return result;
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}
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std::vector<uint32_t> TransformationOutlineFunction::GetRegionInputIds(
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opt::IRContext* ir_context, const std::set<opt::BasicBlock*>& region_set,
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opt::BasicBlock* region_exit_block) {
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std::vector<uint32_t> result;
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auto enclosing_function = region_exit_block->GetParent();
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// Consider each parameter of the function containing the region.
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enclosing_function->ForEachParam(
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[ir_context, ®ion_set, &result](opt::Instruction* function_parameter) {
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// Consider every use of the parameter.
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ir_context->get_def_use_mgr()->WhileEachUse(
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function_parameter,
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[ir_context, function_parameter, ®ion_set, &result](
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opt::Instruction* use, uint32_t /*unused*/) {
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// Get the block, if any, in which the parameter is used.
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auto use_block = ir_context->get_instr_block(use);
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// If the use is in a block that lies within the region, the
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// parameter is an input id for the region.
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if (use_block && region_set.count(use_block) != 0) {
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result.push_back(function_parameter->result_id());
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return false;
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}
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return true;
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});
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});
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// Consider all definitions in the function that might turn out to be input
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// ids.
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for (auto& block : *enclosing_function) {
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std::vector<opt::Instruction*> candidate_input_ids_for_block;
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if (region_set.count(&block) == 0) {
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// All instructions in blocks outside the region are candidate's for
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// generating input ids.
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for (auto& inst : block) {
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candidate_input_ids_for_block.push_back(&inst);
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}
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} else {
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// Blocks in the region cannot generate input ids.
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continue;
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}
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// Consider each candidate input id to check whether it is used in the
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// region.
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for (auto& inst : candidate_input_ids_for_block) {
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ir_context->get_def_use_mgr()->WhileEachUse(
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inst,
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[ir_context, &inst, region_exit_block, ®ion_set, &result](
|
|
opt::Instruction* use, uint32_t /*unused*/) -> bool {
|
|
|
|
// Find the block in which this id use occurs, recording the id as
|
|
// an input id if the block is outside the region, with some
|
|
// exceptions detailed below.
|
|
auto use_block = ir_context->get_instr_block(use);
|
|
|
|
if (!use_block) {
|
|
// There might be no containing block, e.g. if the use is in a
|
|
// decoration.
|
|
return true;
|
|
}
|
|
|
|
if (region_set.count(use_block) == 0) {
|
|
// The use is not in the region: this does not make it an input
|
|
// id.
|
|
return true;
|
|
}
|
|
|
|
if (use_block == region_exit_block && use->IsBlockTerminator()) {
|
|
// We do not regard uses in the exit block terminator as input
|
|
// ids, as this terminator does not get outlined.
|
|
return true;
|
|
}
|
|
|
|
result.push_back(inst->result_id());
|
|
return false;
|
|
});
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
std::vector<uint32_t> TransformationOutlineFunction::GetRegionOutputIds(
|
|
opt::IRContext* ir_context, const std::set<opt::BasicBlock*>& region_set,
|
|
opt::BasicBlock* region_exit_block) {
|
|
std::vector<uint32_t> result;
|
|
|
|
// Consider each block in the function containing the region.
|
|
for (auto& block : *region_exit_block->GetParent()) {
|
|
if (region_set.count(&block) == 0) {
|
|
// Skip blocks that are not in the region.
|
|
continue;
|
|
}
|
|
// Consider each use of each instruction defined in the block.
|
|
for (auto& inst : block) {
|
|
ir_context->get_def_use_mgr()->WhileEachUse(
|
|
&inst,
|
|
[®ion_set, ir_context, &inst, region_exit_block, &result](
|
|
opt::Instruction* use, uint32_t /*unused*/) -> bool {
|
|
|
|
// Find the block in which this id use occurs, recording the id as
|
|
// an output id if the block is outside the region, with some
|
|
// exceptions detailed below.
|
|
auto use_block = ir_context->get_instr_block(use);
|
|
|
|
if (!use_block) {
|
|
// There might be no containing block, e.g. if the use is in a
|
|
// decoration.
|
|
return true;
|
|
}
|
|
|
|
if (region_set.count(use_block) != 0) {
|
|
// The use is in the region.
|
|
if (use_block != region_exit_block || !use->IsBlockTerminator()) {
|
|
// Furthermore, the use is not in the terminator of the region's
|
|
// exit block.
|
|
return true;
|
|
}
|
|
}
|
|
|
|
result.push_back(inst.result_id());
|
|
return false;
|
|
});
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
std::set<opt::BasicBlock*> TransformationOutlineFunction::GetRegionBlocks(
|
|
opt::IRContext* ir_context, opt::BasicBlock* entry_block,
|
|
opt::BasicBlock* exit_block) {
|
|
auto enclosing_function = entry_block->GetParent();
|
|
auto dominator_analysis =
|
|
ir_context->GetDominatorAnalysis(enclosing_function);
|
|
auto postdominator_analysis =
|
|
ir_context->GetPostDominatorAnalysis(enclosing_function);
|
|
|
|
std::set<opt::BasicBlock*> result;
|
|
for (auto& block : *enclosing_function) {
|
|
if (dominator_analysis->Dominates(entry_block, &block) &&
|
|
postdominator_analysis->Dominates(exit_block, &block)) {
|
|
result.insert(&block);
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
std::unique_ptr<opt::Function>
|
|
TransformationOutlineFunction::PrepareFunctionPrototype(
|
|
const std::vector<uint32_t>& region_input_ids,
|
|
const std::vector<uint32_t>& region_output_ids,
|
|
const std::map<uint32_t, uint32_t>& input_id_to_fresh_id_map,
|
|
opt::IRContext* ir_context,
|
|
TransformationContext* transformation_context) const {
|
|
uint32_t return_type_id = 0;
|
|
uint32_t function_type_id = 0;
|
|
|
|
// First, try to find an existing function type that is suitable. This is
|
|
// only possible if the region generates no output ids; if it generates output
|
|
// ids we are going to make a new struct for those, and since that struct does
|
|
// not exist there cannot already be a function type with this struct as its
|
|
// return type.
|
|
if (region_output_ids.empty()) {
|
|
std::vector<uint32_t> return_and_parameter_types;
|
|
opt::analysis::Void void_type;
|
|
return_type_id = ir_context->get_type_mgr()->GetId(&void_type);
|
|
return_and_parameter_types.push_back(return_type_id);
|
|
for (auto id : region_input_ids) {
|
|
return_and_parameter_types.push_back(
|
|
ir_context->get_def_use_mgr()->GetDef(id)->type_id());
|
|
}
|
|
function_type_id =
|
|
fuzzerutil::FindFunctionType(ir_context, return_and_parameter_types);
|
|
}
|
|
|
|
// If no existing function type was found, we need to create one.
|
|
if (function_type_id == 0) {
|
|
assert(
|
|
((return_type_id == 0) == !region_output_ids.empty()) &&
|
|
"We should only have set the return type if there are no output ids.");
|
|
// If the region generates output ids, we need to make a struct with one
|
|
// field per output id.
|
|
if (!region_output_ids.empty()) {
|
|
opt::Instruction::OperandList struct_member_types;
|
|
for (uint32_t output_id : region_output_ids) {
|
|
auto output_id_type =
|
|
ir_context->get_def_use_mgr()->GetDef(output_id)->type_id();
|
|
struct_member_types.push_back({SPV_OPERAND_TYPE_ID, {output_id_type}});
|
|
}
|
|
// Add a new struct type to the module.
|
|
ir_context->module()->AddType(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpTypeStruct, 0,
|
|
message_.new_function_struct_return_type_id(),
|
|
std::move(struct_member_types)));
|
|
// The return type for the function is the newly-created struct.
|
|
return_type_id = message_.new_function_struct_return_type_id();
|
|
}
|
|
assert(
|
|
return_type_id != 0 &&
|
|
"We should either have a void return type, or have created a struct.");
|
|
|
|
// The region's input ids dictate the parameter types to the function.
|
|
opt::Instruction::OperandList function_type_operands;
|
|
function_type_operands.push_back({SPV_OPERAND_TYPE_ID, {return_type_id}});
|
|
for (auto id : region_input_ids) {
|
|
function_type_operands.push_back(
|
|
{SPV_OPERAND_TYPE_ID,
|
|
{ir_context->get_def_use_mgr()->GetDef(id)->type_id()}});
|
|
}
|
|
// Add a new function type to the module, and record that this is the type
|
|
// id for the new function.
|
|
ir_context->module()->AddType(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpTypeFunction, 0, message_.new_function_type_id(),
|
|
function_type_operands));
|
|
function_type_id = message_.new_function_type_id();
|
|
}
|
|
|
|
// Create a new function with |message_.new_function_id| as the function id,
|
|
// and the return type and function type prepared above.
|
|
std::unique_ptr<opt::Function> outlined_function =
|
|
MakeUnique<opt::Function>(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpFunction, return_type_id, message_.new_function_id(),
|
|
opt::Instruction::OperandList(
|
|
{{spv_operand_type_t ::SPV_OPERAND_TYPE_LITERAL_INTEGER,
|
|
{SpvFunctionControlMaskNone}},
|
|
{spv_operand_type_t::SPV_OPERAND_TYPE_ID,
|
|
{function_type_id}}})));
|
|
|
|
// Add one parameter to the function for each input id, using the fresh ids
|
|
// provided in |input_id_to_fresh_id_map|.
|
|
for (auto id : region_input_ids) {
|
|
outlined_function->AddParameter(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpFunctionParameter,
|
|
ir_context->get_def_use_mgr()->GetDef(id)->type_id(),
|
|
input_id_to_fresh_id_map.at(id), opt::Instruction::OperandList()));
|
|
// If the input id is an irrelevant-valued variable, the same should be true
|
|
// of the corresponding parameter.
|
|
if (transformation_context->GetFactManager()->PointeeValueIsIrrelevant(
|
|
id)) {
|
|
transformation_context->GetFactManager()
|
|
->AddFactValueOfPointeeIsIrrelevant(input_id_to_fresh_id_map.at(id));
|
|
}
|
|
}
|
|
|
|
return outlined_function;
|
|
}
|
|
|
|
void TransformationOutlineFunction::UpdateModuleIdBoundForFreshIds(
|
|
opt::IRContext* ir_context,
|
|
const std::map<uint32_t, uint32_t>& input_id_to_fresh_id_map,
|
|
const std::map<uint32_t, uint32_t>& output_id_to_fresh_id_map) const {
|
|
// Enlarge the module's id bound as needed to accommodate the various fresh
|
|
// ids associated with the transformation.
|
|
fuzzerutil::UpdateModuleIdBound(
|
|
ir_context, message_.new_function_struct_return_type_id());
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, message_.new_function_type_id());
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, message_.new_function_id());
|
|
fuzzerutil::UpdateModuleIdBound(ir_context,
|
|
message_.new_function_region_entry_block());
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, message_.new_caller_result_id());
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, message_.new_callee_result_id());
|
|
|
|
for (auto& entry : input_id_to_fresh_id_map) {
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, entry.second);
|
|
}
|
|
|
|
for (auto& entry : output_id_to_fresh_id_map) {
|
|
fuzzerutil::UpdateModuleIdBound(ir_context, entry.second);
|
|
}
|
|
}
|
|
|
|
void TransformationOutlineFunction::RemapInputAndOutputIdsInRegion(
|
|
opt::IRContext* ir_context,
|
|
const opt::BasicBlock& original_region_exit_block,
|
|
const std::set<opt::BasicBlock*>& region_blocks,
|
|
const std::vector<uint32_t>& region_input_ids,
|
|
const std::vector<uint32_t>& region_output_ids,
|
|
const std::map<uint32_t, uint32_t>& input_id_to_fresh_id_map,
|
|
const std::map<uint32_t, uint32_t>& output_id_to_fresh_id_map) const {
|
|
// Change all uses of input ids inside the region to the corresponding fresh
|
|
// ids that will ultimately be parameters of the outlined function.
|
|
// This is done by considering each region input id in turn.
|
|
for (uint32_t id : region_input_ids) {
|
|
// We then consider each use of the input id.
|
|
ir_context->get_def_use_mgr()->ForEachUse(
|
|
id, [ir_context, id, &input_id_to_fresh_id_map, region_blocks](
|
|
opt::Instruction* use, uint32_t operand_index) {
|
|
// Find the block in which this use of the input id occurs.
|
|
opt::BasicBlock* use_block = ir_context->get_instr_block(use);
|
|
// We want to rewrite the use id if its block occurs in the outlined
|
|
// region.
|
|
if (region_blocks.count(use_block) != 0) {
|
|
// Rewrite this use of the input id.
|
|
use->SetOperand(operand_index, {input_id_to_fresh_id_map.at(id)});
|
|
}
|
|
});
|
|
}
|
|
|
|
// Change each definition of a region output id to define the corresponding
|
|
// fresh ids that will store intermediate value for the output ids. Also
|
|
// change all uses of the output id located in the outlined region.
|
|
// This is done by considering each region output id in turn.
|
|
for (uint32_t id : region_output_ids) {
|
|
// First consider each use of the output id and update the relevant uses.
|
|
ir_context->get_def_use_mgr()->ForEachUse(
|
|
id, [ir_context, &original_region_exit_block, id,
|
|
&output_id_to_fresh_id_map,
|
|
region_blocks](opt::Instruction* use, uint32_t operand_index) {
|
|
// Find the block in which this use of the output id occurs.
|
|
auto use_block = ir_context->get_instr_block(use);
|
|
// We want to rewrite the use id if its block occurs in the outlined
|
|
// region, with one exception: the terminator of the exit block of
|
|
// the region is going to remain in the original function, so if the
|
|
// use appears in such a terminator instruction we leave it alone.
|
|
if (
|
|
// The block is in the region ...
|
|
region_blocks.count(use_block) != 0 &&
|
|
// ... and the use is not in the terminator instruction of the
|
|
// region's exit block.
|
|
!(use_block == &original_region_exit_block &&
|
|
use->IsBlockTerminator())) {
|
|
// Rewrite this use of the output id.
|
|
use->SetOperand(operand_index, {output_id_to_fresh_id_map.at(id)});
|
|
}
|
|
});
|
|
|
|
// Now change the instruction that defines the output id so that it instead
|
|
// defines the corresponding fresh id. We do this after changing all the
|
|
// uses so that the definition of the original id is still registered when
|
|
// we analyse its uses.
|
|
ir_context->get_def_use_mgr()->GetDef(id)->SetResultId(
|
|
output_id_to_fresh_id_map.at(id));
|
|
}
|
|
}
|
|
|
|
void TransformationOutlineFunction::PopulateOutlinedFunction(
|
|
const opt::BasicBlock& original_region_entry_block,
|
|
const opt::BasicBlock& original_region_exit_block,
|
|
const std::set<opt::BasicBlock*>& region_blocks,
|
|
const std::vector<uint32_t>& region_output_ids,
|
|
const std::map<uint32_t, uint32_t>& output_id_to_fresh_id_map,
|
|
opt::IRContext* ir_context, opt::Function* outlined_function,
|
|
TransformationContext* transformation_context) const {
|
|
// When we create the exit block for the outlined region, we use this pointer
|
|
// to track of it so that we can manipulate it later.
|
|
opt::BasicBlock* outlined_region_exit_block = nullptr;
|
|
|
|
// The region entry block in the new function is identical to the entry block
|
|
// of the region being outlined, except that it has
|
|
// |message_.new_function_region_entry_block| as its id.
|
|
std::unique_ptr<opt::BasicBlock> outlined_region_entry_block =
|
|
MakeUnique<opt::BasicBlock>(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpLabel, 0, message_.new_function_region_entry_block(),
|
|
opt::Instruction::OperandList()));
|
|
outlined_region_entry_block->SetParent(outlined_function);
|
|
|
|
// If the original region's entry block was dead, the outlined region's entry
|
|
// block is also dead.
|
|
if (transformation_context->GetFactManager()->BlockIsDead(
|
|
original_region_entry_block.id())) {
|
|
transformation_context->GetFactManager()->AddFactBlockIsDead(
|
|
outlined_region_entry_block->id());
|
|
}
|
|
|
|
if (&original_region_entry_block == &original_region_exit_block) {
|
|
outlined_region_exit_block = outlined_region_entry_block.get();
|
|
}
|
|
|
|
for (auto& inst : original_region_entry_block) {
|
|
outlined_region_entry_block->AddInstruction(
|
|
std::unique_ptr<opt::Instruction>(inst.Clone(ir_context)));
|
|
}
|
|
outlined_function->AddBasicBlock(std::move(outlined_region_entry_block));
|
|
|
|
// We now go through the single-entry single-exit region defined by the entry
|
|
// and exit blocks, adding clones of all blocks to the new function.
|
|
|
|
// Consider every block in the enclosing function.
|
|
auto enclosing_function = original_region_entry_block.GetParent();
|
|
for (auto block_it = enclosing_function->begin();
|
|
block_it != enclosing_function->end();) {
|
|
// Skip the region's entry block - we already dealt with it above.
|
|
if (region_blocks.count(&*block_it) == 0 ||
|
|
&*block_it == &original_region_entry_block) {
|
|
++block_it;
|
|
continue;
|
|
}
|
|
// Clone the block so that it can be added to the new function.
|
|
auto cloned_block =
|
|
std::unique_ptr<opt::BasicBlock>(block_it->Clone(ir_context));
|
|
|
|
// If this is the region's exit block, then the cloned block is the outlined
|
|
// region's exit block.
|
|
if (&*block_it == &original_region_exit_block) {
|
|
assert(outlined_region_exit_block == nullptr &&
|
|
"We should not yet have encountered the exit block.");
|
|
outlined_region_exit_block = cloned_block.get();
|
|
}
|
|
|
|
cloned_block->SetParent(outlined_function);
|
|
|
|
// Redirect any OpPhi operands whose predecessors are the original region
|
|
// entry block to become the new function entry block.
|
|
cloned_block->ForEachPhiInst([this](opt::Instruction* phi_inst) {
|
|
for (uint32_t predecessor_index = 1;
|
|
predecessor_index < phi_inst->NumInOperands();
|
|
predecessor_index += 2) {
|
|
if (phi_inst->GetSingleWordInOperand(predecessor_index) ==
|
|
message_.entry_block()) {
|
|
phi_inst->SetInOperand(predecessor_index,
|
|
{message_.new_function_region_entry_block()});
|
|
}
|
|
}
|
|
});
|
|
|
|
outlined_function->AddBasicBlock(std::move(cloned_block));
|
|
block_it = block_it.Erase();
|
|
}
|
|
assert(outlined_region_exit_block != nullptr &&
|
|
"We should have encountered the region's exit block when iterating "
|
|
"through the function");
|
|
|
|
// We now need to adapt the exit block for the region - in the new function -
|
|
// so that it ends with a return.
|
|
|
|
// We first eliminate the merge instruction (if any) and the terminator for
|
|
// the cloned exit block.
|
|
for (auto inst_it = outlined_region_exit_block->begin();
|
|
inst_it != outlined_region_exit_block->end();) {
|
|
if (inst_it->opcode() == SpvOpLoopMerge ||
|
|
inst_it->opcode() == SpvOpSelectionMerge) {
|
|
inst_it = inst_it.Erase();
|
|
} else if (inst_it->IsBlockTerminator()) {
|
|
inst_it = inst_it.Erase();
|
|
} else {
|
|
++inst_it;
|
|
}
|
|
}
|
|
|
|
// We now add either OpReturn or OpReturnValue as the cloned exit block's
|
|
// terminator.
|
|
if (region_output_ids.empty()) {
|
|
// The case where there are no region output ids is simple: we just add
|
|
// OpReturn.
|
|
outlined_region_exit_block->AddInstruction(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpReturn, 0, 0, opt::Instruction::OperandList()));
|
|
} else {
|
|
// In the case where there are output ids, we add an OpCompositeConstruct
|
|
// instruction to pack all the output values into a struct, and then an
|
|
// OpReturnValue instruction to return this struct.
|
|
opt::Instruction::OperandList struct_member_operands;
|
|
for (uint32_t id : region_output_ids) {
|
|
struct_member_operands.push_back(
|
|
{SPV_OPERAND_TYPE_ID, {output_id_to_fresh_id_map.at(id)}});
|
|
}
|
|
outlined_region_exit_block->AddInstruction(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpCompositeConstruct,
|
|
message_.new_function_struct_return_type_id(),
|
|
message_.new_callee_result_id(), struct_member_operands));
|
|
outlined_region_exit_block->AddInstruction(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpReturnValue, 0, 0,
|
|
opt::Instruction::OperandList(
|
|
{{SPV_OPERAND_TYPE_ID, {message_.new_callee_result_id()}}})));
|
|
}
|
|
|
|
outlined_function->SetFunctionEnd(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpFunctionEnd, 0, 0, opt::Instruction::OperandList()));
|
|
}
|
|
|
|
void TransformationOutlineFunction::ShrinkOriginalRegion(
|
|
opt::IRContext* ir_context, std::set<opt::BasicBlock*>& region_blocks,
|
|
const std::vector<uint32_t>& region_input_ids,
|
|
const std::vector<uint32_t>& region_output_ids,
|
|
const std::map<uint32_t, uint32_t>& output_id_to_type_id,
|
|
uint32_t return_type_id,
|
|
std::unique_ptr<opt::Instruction> cloned_exit_block_merge,
|
|
std::unique_ptr<opt::Instruction> cloned_exit_block_terminator,
|
|
opt::BasicBlock* original_region_entry_block) const {
|
|
// Erase all blocks from the original function that are in the outlined
|
|
// region, except for the region's entry block.
|
|
//
|
|
// In the process, identify all references to the exit block of the region,
|
|
// as merge blocks, continue targets, or OpPhi predecessors, and rewrite them
|
|
// to refer to the region entry block (the single block to which we are
|
|
// shrinking the region).
|
|
auto enclosing_function = original_region_entry_block->GetParent();
|
|
for (auto block_it = enclosing_function->begin();
|
|
block_it != enclosing_function->end();) {
|
|
if (&*block_it == original_region_entry_block) {
|
|
++block_it;
|
|
} else if (region_blocks.count(&*block_it) == 0) {
|
|
// The block is not in the region. Check whether it has the last block
|
|
// of the region as an OpPhi predecessor, and if so change the
|
|
// predecessor to be the first block of the region (i.e. the block
|
|
// containing the call to what was outlined).
|
|
assert(block_it->MergeBlockIdIfAny() != message_.exit_block() &&
|
|
"Outlined region must not end with a merge block");
|
|
assert(block_it->ContinueBlockIdIfAny() != message_.exit_block() &&
|
|
"Outlined region must not end with a continue target");
|
|
block_it->ForEachPhiInst([this](opt::Instruction* phi_inst) {
|
|
for (uint32_t predecessor_index = 1;
|
|
predecessor_index < phi_inst->NumInOperands();
|
|
predecessor_index += 2) {
|
|
if (phi_inst->GetSingleWordInOperand(predecessor_index) ==
|
|
message_.exit_block()) {
|
|
phi_inst->SetInOperand(predecessor_index, {message_.entry_block()});
|
|
}
|
|
}
|
|
});
|
|
++block_it;
|
|
} else {
|
|
// The block is in the region and is not the region's entry block: kill
|
|
// it.
|
|
block_it = block_it.Erase();
|
|
}
|
|
}
|
|
|
|
// Now erase all instructions from the region's entry block, as they have
|
|
// been outlined.
|
|
for (auto inst_it = original_region_entry_block->begin();
|
|
inst_it != original_region_entry_block->end();) {
|
|
inst_it = inst_it.Erase();
|
|
}
|
|
|
|
// Now we add a call to the outlined function to the region's entry block.
|
|
opt::Instruction::OperandList function_call_operands;
|
|
function_call_operands.push_back(
|
|
{SPV_OPERAND_TYPE_ID, {message_.new_function_id()}});
|
|
// The function parameters are the region input ids.
|
|
for (auto input_id : region_input_ids) {
|
|
function_call_operands.push_back({SPV_OPERAND_TYPE_ID, {input_id}});
|
|
}
|
|
|
|
original_region_entry_block->AddInstruction(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpFunctionCall, return_type_id,
|
|
message_.new_caller_result_id(), function_call_operands));
|
|
|
|
// If there are output ids, the function call will return a struct. For each
|
|
// output id, we add an extract operation to pull the appropriate struct
|
|
// member out into an output id.
|
|
for (uint32_t index = 0; index < region_output_ids.size(); ++index) {
|
|
uint32_t output_id = region_output_ids[index];
|
|
original_region_entry_block->AddInstruction(MakeUnique<opt::Instruction>(
|
|
ir_context, SpvOpCompositeExtract, output_id_to_type_id.at(output_id),
|
|
output_id,
|
|
opt::Instruction::OperandList(
|
|
{{SPV_OPERAND_TYPE_ID, {message_.new_caller_result_id()}},
|
|
{SPV_OPERAND_TYPE_LITERAL_INTEGER, {index}}})));
|
|
}
|
|
|
|
// Finally, we terminate the block with the merge instruction (if any) that
|
|
// used to belong to the region's exit block, and the terminator that used
|
|
// to belong to the region's exit block.
|
|
if (cloned_exit_block_merge != nullptr) {
|
|
original_region_entry_block->AddInstruction(
|
|
std::move(cloned_exit_block_merge));
|
|
}
|
|
original_region_entry_block->AddInstruction(
|
|
std::move(cloned_exit_block_terminator));
|
|
}
|
|
|
|
} // namespace fuzz
|
|
} // namespace spvtools
|