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https://github.com/KhronosGroup/SPIRV-Tools
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a687057a83
This commit lets the vector DCE pass preserve the OpenCL.DebugInfo.100 information properly. When the vector DCE pass determines the liveness of instructions, the debug instructions must not affect the decision. In addition, when it kills some instructions, it has to kill DebugValue instructions that use the killed instructions. When it updates some composite values to meaningful values (not undef), it has to remove DebugValue because the value information becomes incorrect.
158 lines
6.6 KiB
C++
158 lines
6.6 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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#ifndef SOURCE_OPT_VECTOR_DCE_H_
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#define SOURCE_OPT_VECTOR_DCE_H_
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#include <unordered_map>
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#include <vector>
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#include "source/opt/mem_pass.h"
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#include "source/util/bit_vector.h"
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namespace spvtools {
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namespace opt {
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class VectorDCE : public MemPass {
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private:
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using LiveComponentMap = std::unordered_map<uint32_t, utils::BitVector>;
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// According to the SPEC the maximum size for a vector is 16. See the data
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// rules in the universal validation rules (section 2.16.1).
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enum { kMaxVectorSize = 16 };
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struct WorkListItem {
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WorkListItem() : instruction(nullptr), components(kMaxVectorSize) {}
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Instruction* instruction;
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utils::BitVector components;
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};
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public:
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VectorDCE() : all_components_live_(kMaxVectorSize) {
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for (uint32_t i = 0; i < kMaxVectorSize; i++) {
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all_components_live_.Set(i);
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}
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}
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const char* name() const override { return "vector-dce"; }
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Status Process() override;
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IRContext::Analysis GetPreservedAnalyses() override {
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return IRContext::kAnalysisDefUse | IRContext::kAnalysisCFG |
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IRContext::kAnalysisInstrToBlockMapping |
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IRContext::kAnalysisLoopAnalysis | IRContext::kAnalysisDecorations |
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IRContext::kAnalysisDominatorAnalysis | IRContext::kAnalysisNameMap |
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IRContext::kAnalysisConstants | IRContext::kAnalysisTypes;
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}
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private:
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// Runs the vector dce pass on |function|. Returns true if |function| was
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// modified.
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bool VectorDCEFunction(Function* function);
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// Identifies the live components of the vectors that are results of
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// instructions in |function|. The results are stored in |live_components|.
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void FindLiveComponents(Function* function,
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LiveComponentMap* live_components);
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// Rewrites instructions in |function| that are dead or partially dead. If an
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// instruction does not have an entry in |live_components|, then it is not
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// changed. Returns true if |function| was modified.
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bool RewriteInstructions(Function* function,
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const LiveComponentMap& live_components);
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// Makrs all DebugValue instructions that use |composite| for their values as
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// dead instructions by putting them into |dead_dbg_value|.
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void MarkDebugValueUsesAsDead(Instruction* composite,
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std::vector<Instruction*>* dead_dbg_value);
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// Rewrites the OpCompositeInsert instruction |current_inst| to avoid
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// unnecessary computes given that the only components of the result that are
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// live are |live_components|.
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//
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// If the value being inserted is not live, then the result of |current_inst|
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// is replaced by the composite input to |current_inst|.
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//
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// If the composite input to |current_inst| is not live, then it is replaced
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// by and OpUndef in |current_inst|.
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bool RewriteInsertInstruction(Instruction* current_inst,
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const utils::BitVector& live_components,
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std::vector<Instruction*>* dead_dbg_value);
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// Returns true if the result of |inst| is a vector or a scalar.
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bool HasVectorOrScalarResult(const Instruction* inst) const;
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// Returns true if the result of |inst| is a scalar.
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bool HasVectorResult(const Instruction* inst) const;
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// Returns true if the result of |inst| is a vector.
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bool HasScalarResult(const Instruction* inst) const;
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// Adds |work_item| to |work_list| if it is not already live according to
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// |live_components|. |live_components| is updated to indicate that
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// |work_item| is now live.
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void AddItemToWorkListIfNeeded(WorkListItem work_item,
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LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// Marks the components |live_elements| of the uses in |current_inst| as live
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// according to |live_components|. If they were not live before, then they are
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// added to |work_list|.
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void MarkUsesAsLive(Instruction* current_inst,
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const utils::BitVector& live_elements,
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LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// Marks the uses in the OpVectorShuffle instruction in |current_item| as live
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// based on the live components in |current_item|. If anything becomes live
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// they are added to |work_list| and |live_components| is updated
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// accordingly.
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void MarkVectorShuffleUsesAsLive(const WorkListItem& current_item,
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VectorDCE::LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// Marks the uses in the OpCompositeInsert instruction in |current_item| as
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// live based on the live components in |current_item|. If anything becomes
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// live they are added to |work_list| and |live_components| is updated
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// accordingly.
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void MarkInsertUsesAsLive(const WorkListItem& current_item,
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LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// Marks the uses in the OpCompositeExtract instruction |current_inst| as
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// live. If anything becomes live they are added to |work_list| and
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// |live_components| is updated accordingly.
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void MarkExtractUseAsLive(const Instruction* current_inst,
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const utils::BitVector& live_elements,
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LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// Marks the uses in the OpCompositeConstruct instruction |current_inst| as
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// live. If anything becomes live they are added to |work_list| and
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// |live_components| is updated accordingly.
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void MarkCompositeContructUsesAsLive(WorkListItem work_item,
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LiveComponentMap* live_components,
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std::vector<WorkListItem>* work_list);
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// A BitVector that can always be used to say that all components of a vector
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// are live.
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utils::BitVector all_components_live_;
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};
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} // namespace opt
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} // namespace spvtools
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#endif // SOURCE_OPT_VECTOR_DCE_H_
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