| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * 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. |
| */ |
| |
| #ifndef ART_COMPILER_OPTIMIZING_SSA_BUILDER_H_ |
| #define ART_COMPILER_OPTIMIZING_SSA_BUILDER_H_ |
| |
| #include "nodes.h" |
| #include "optimization.h" |
| |
| namespace art { |
| |
| static constexpr int kDefaultNumberOfLoops = 2; |
| |
| /** |
| * Transforms a graph into SSA form. The liveness guarantees of |
| * this transformation are listed below. A DEX register |
| * being killed means its value at a given position in the code |
| * will not be available to its environment uses. A merge in the |
| * following text is materialized as a `HPhi`. |
| * |
| * (a) Dex registers that do not require merging (that is, they do not |
| * have different values at a join block) are available to all their |
| * environment uses. Note that it does not imply the instruction will |
| * have a physical location after register allocation. See the |
| * SsaLivenessAnalysis phase. |
| * |
| * (b) Dex registers that require merging, and the merging gives |
| * incompatible types, will be killed for environment uses of that merge. |
| * |
| * (c) When the `debuggable` flag is passed to the compiler, Dex registers |
| * that require merging and have a proper type after the merge, are |
| * available to all their environment uses. If the `debuggable` flag |
| * is not set, values of Dex registers only used by environments |
| * are killed. |
| */ |
| class SsaBuilder : public HGraphVisitor { |
| public: |
| explicit SsaBuilder(HGraph* graph) |
| : HGraphVisitor(graph), |
| current_locals_(nullptr), |
| loop_headers_(graph->GetArena(), kDefaultNumberOfLoops), |
| locals_for_(graph->GetArena(), graph->GetBlocks().Size()) { |
| locals_for_.SetSize(graph->GetBlocks().Size()); |
| } |
| |
| void BuildSsa(); |
| |
| HEnvironment* GetLocalsFor(HBasicBlock* block) { |
| HEnvironment* env = locals_for_.Get(block->GetBlockId()); |
| if (env == nullptr) { |
| env = new (GetGraph()->GetArena()) HEnvironment( |
| GetGraph()->GetArena(), GetGraph()->GetNumberOfVRegs()); |
| locals_for_.Put(block->GetBlockId(), env); |
| } |
| return env; |
| } |
| |
| HInstruction* ValueOfLocal(HBasicBlock* block, size_t local); |
| |
| void VisitBasicBlock(HBasicBlock* block); |
| void VisitLoadLocal(HLoadLocal* load); |
| void VisitStoreLocal(HStoreLocal* store); |
| void VisitInstruction(HInstruction* instruction); |
| void VisitTemporary(HTemporary* instruction); |
| |
| static HInstruction* GetFloatOrDoubleEquivalent(HInstruction* user, |
| HInstruction* instruction, |
| Primitive::Type type); |
| |
| static HInstruction* GetReferenceTypeEquivalent(HInstruction* instruction); |
| |
| static constexpr const char* kSsaBuilderPassName = "ssa_builder"; |
| |
| private: |
| // Locals for the current block being visited. |
| HEnvironment* current_locals_; |
| |
| // Keep track of loop headers found. The last phase of the analysis iterates |
| // over these blocks to set the inputs of their phis. |
| GrowableArray<HBasicBlock*> loop_headers_; |
| |
| // HEnvironment for each block. |
| GrowableArray<HEnvironment*> locals_for_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SsaBuilder); |
| }; |
| |
| } // namespace art |
| |
| #endif // ART_COMPILER_OPTIMIZING_SSA_BUILDER_H_ |