131 lines
3.8 KiB
C++
131 lines
3.8 KiB
C++
// Copyright (c) 2018 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/opt/struct_cfg_analysis.h"
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#include "source/opt/ir_context.h"
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namespace {
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const uint32_t kMergeNodeIndex = 0;
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const uint32_t kContinueNodeIndex = 1;
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} // namespace
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namespace spvtools {
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namespace opt {
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StructuredCFGAnalysis::StructuredCFGAnalysis(IRContext* ctx) : context_(ctx) {
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// If this is not a shader, there are no merge instructions, and not
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// structured CFG to analyze.
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if (!context_->get_feature_mgr()->HasCapability(SpvCapabilityShader)) {
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return;
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}
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for (auto& func : *context_->module()) {
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AddBlocksInFunction(&func);
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}
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}
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void StructuredCFGAnalysis::AddBlocksInFunction(Function* func) {
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if (func->begin() == func->end()) return;
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std::list<BasicBlock*> order;
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context_->cfg()->ComputeStructuredOrder(func, &*func->begin(), &order);
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struct TraversalInfo {
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ConstructInfo cinfo;
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uint32_t merge_node;
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};
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// Set up a stack to keep track of currently active constructs.
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std::vector<TraversalInfo> state;
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state.emplace_back();
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state[0].cinfo.containing_construct = 0;
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state[0].cinfo.containing_loop = 0;
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state[0].merge_node = 0;
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for (BasicBlock* block : order) {
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if (context_->cfg()->IsPseudoEntryBlock(block) ||
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context_->cfg()->IsPseudoExitBlock(block)) {
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continue;
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}
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if (block->id() == state.back().merge_node) {
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state.pop_back();
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}
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bb_to_construct_.emplace(std::make_pair(block->id(), state.back().cinfo));
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if (Instruction* merge_inst = block->GetMergeInst()) {
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TraversalInfo new_state;
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new_state.merge_node =
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merge_inst->GetSingleWordInOperand(kMergeNodeIndex);
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new_state.cinfo.containing_construct = block->id();
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if (merge_inst->opcode() == SpvOpLoopMerge) {
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new_state.cinfo.containing_loop = block->id();
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} else {
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new_state.cinfo.containing_loop = state.back().cinfo.containing_loop;
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}
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state.emplace_back(new_state);
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merge_blocks_.Set(new_state.merge_node);
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}
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}
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}
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uint32_t StructuredCFGAnalysis::MergeBlock(uint32_t bb_id) {
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uint32_t header_id = ContainingConstruct(bb_id);
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if (header_id == 0) {
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return 0;
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}
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BasicBlock* header = context_->cfg()->block(header_id);
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Instruction* merge_inst = header->GetMergeInst();
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return merge_inst->GetSingleWordInOperand(kMergeNodeIndex);
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}
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uint32_t StructuredCFGAnalysis::LoopMergeBlock(uint32_t bb_id) {
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uint32_t header_id = ContainingLoop(bb_id);
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if (header_id == 0) {
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return 0;
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}
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BasicBlock* header = context_->cfg()->block(header_id);
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Instruction* merge_inst = header->GetMergeInst();
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return merge_inst->GetSingleWordInOperand(kMergeNodeIndex);
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}
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uint32_t StructuredCFGAnalysis::LoopContinueBlock(uint32_t bb_id) {
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uint32_t header_id = ContainingLoop(bb_id);
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if (header_id == 0) {
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return 0;
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}
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BasicBlock* header = context_->cfg()->block(header_id);
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Instruction* merge_inst = header->GetMergeInst();
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return merge_inst->GetSingleWordInOperand(kContinueNodeIndex);
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}
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bool StructuredCFGAnalysis::IsContinueBlock(uint32_t bb_id) {
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assert(bb_id != 0);
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return LoopContinueBlock(bb_id) == bb_id;
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}
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bool StructuredCFGAnalysis::IsMergeBlock(uint32_t bb_id) {
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return merge_blocks_.Get(bb_id);
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}
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} // namespace opt
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} // namespace spvtools
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