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| 1 | +/* |
| 2 | + * Licensed to the Apache Software Foundation (ASF) under one |
| 3 | + * or more contributor license agreements. See the NOTICE file |
| 4 | + * distributed with this work for additional information |
| 5 | + * regarding copyright ownership. The ASF licenses this file |
| 6 | + * to you under the Apache License, Version 2.0 (the |
| 7 | + * "License"); you may not use this file except in compliance |
| 8 | + * with the License. You may obtain a copy of the License at |
| 9 | + * |
| 10 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | + * |
| 12 | + * Unless required by applicable law or agreed to in writing, |
| 13 | + * software distributed under the License is distributed on an |
| 14 | + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | + * KIND, either express or implied. See the License for the |
| 16 | + * specific language governing permissions and limitations |
| 17 | + * under the License. |
| 18 | + */ |
| 19 | +#include "../utils.h" |
| 20 | + |
| 21 | +namespace tvm { |
| 22 | +namespace tir { |
| 23 | + |
| 24 | +/*! |
| 25 | + * \brief Collect the block and index where the buffer is read. |
| 26 | + * \note The buffers are expected to be read by only one BufferLoad |
| 27 | + */ |
| 28 | +class BufferReadPosCollector : public StmtExprVisitor { |
| 29 | + public: |
| 30 | + explicit BufferReadPosCollector(const Array<Buffer>& buffers) { |
| 31 | + for (const Buffer& buf : buffers) { |
| 32 | + buffers_.insert(buf.get()); |
| 33 | + } |
| 34 | + } |
| 35 | + |
| 36 | + const std::unordered_map<const BufferNode*, std::pair<Block, int>>& GetBufferLocations() const { |
| 37 | + return buffer_locs_; |
| 38 | + } |
| 39 | + |
| 40 | + const std::unordered_map<const BufferNode*, Optional<IndexMap>>& GetBufferIndexMap() const { |
| 41 | + return buffer_index_maps_; |
| 42 | + } |
| 43 | + |
| 44 | + private: |
| 45 | + void VisitStmt_(const ForNode* op) final { |
| 46 | + loop_stack_.push_back(GetRef<For>(op)); |
| 47 | + StmtVisitor::VisitStmt_(op); |
| 48 | + loop_stack_.pop_back(); |
| 49 | + } |
| 50 | + |
| 51 | + void VisitStmt_(const BlockRealizeNode* op) final { |
| 52 | + BlockRealize outer_block_realize = GetRef<BlockRealize>(op); |
| 53 | + std::swap(outer_block_realize, cur_realize_); |
| 54 | + StmtVisitor::VisitStmt_(op); |
| 55 | + std::swap(cur_realize_, outer_block_realize); |
| 56 | + } |
| 57 | + |
| 58 | + void VisitExpr_(const BufferLoadNode* op) final { |
| 59 | + const Buffer& buffer = op->buffer; |
| 60 | + if (buffers_.count(buffer.get())) { |
| 61 | + Map<Var, PrimExpr> subst_map; |
| 62 | + for (size_t i = 0; i < cur_realize_->iter_values.size(); i++) { |
| 63 | + const Var& var = cur_realize_->block->iter_vars[i]->var; |
| 64 | + const PrimExpr& value = cur_realize_->iter_values[i]; |
| 65 | + subst_map.Set(var, value); |
| 66 | + } |
| 67 | + Array<PrimExpr> subst_indices; |
| 68 | + for (const PrimExpr& e : op->indices) { |
| 69 | + subst_indices.push_back(Substitute(e, subst_map)); |
| 70 | + } |
| 71 | + buffer_index_maps_[buffer.get()] = SuggestIndexMap(/*buffer=*/buffer, // |
| 72 | + /*indices=*/subst_indices, // |
| 73 | + /*loops=*/loop_stack_, // |
| 74 | + /*predicate=*/cur_realize_->predicate, // |
| 75 | + /*analyzer=*/&analyzer_); |
| 76 | + int buffer_index = GetReadBufferIndex(cur_realize_->block, buffer); |
| 77 | + ICHECK(buffer_index != -1); |
| 78 | + buffer_locs_[buffer.get()] = std::make_pair(cur_realize_->block, buffer_index); |
| 79 | + } |
| 80 | + } |
| 81 | + |
| 82 | + static int GetReadBufferIndex(const Block& block, const Buffer& buffer) { |
| 83 | + for (size_t i = 0; i < block->reads.size(); i++) { |
| 84 | + if (block->reads[i]->buffer.same_as(buffer)) { |
| 85 | + return i; |
| 86 | + } |
| 87 | + } |
| 88 | + return -1; |
| 89 | + } |
| 90 | + |
| 91 | + private: |
| 92 | + /*! \brief All interested buffer. */ |
| 93 | + std::unordered_set<const BufferNode*> buffers_; |
| 94 | + /*! \brief The result mapping from buffer to its inner-most block and read index. */ |
| 95 | + std::unordered_map<const BufferNode*, std::pair<Block, int>> buffer_locs_; |
| 96 | + /*! \brief The result mapping from buffer to its IndexMap. */ |
| 97 | + std::unordered_map<const BufferNode*, Optional<IndexMap>> buffer_index_maps_; |
| 98 | + |
| 99 | + /*! \brief Loop stack for calculating IndexMap. */ |
| 100 | + Array<For> loop_stack_; |
| 101 | + /*! \brief Arithmetic analyzer. */ |
| 102 | + arith::Analyzer analyzer_; |
| 103 | + /*! \brief Current BlockRealize scope, used in recursive visit */ |
| 104 | + BlockRealize cur_realize_; |
| 105 | +}; |
| 106 | + |
| 107 | +bool RewriteLayout(const Schedule& sch) { |
| 108 | + std::vector<std::pair<StmtSRef, String>> results; |
| 109 | + for (const auto& kv : sch->mod()->functions) { |
| 110 | + const GlobalVar& g_var = kv.first; |
| 111 | + const String& func_name = g_var->name_hint; |
| 112 | + const auto* prim_func = kv. second. as<PrimFuncNode>(); |
| 113 | + // Only consider PrimFunc |
| 114 | + if (prim_func == nullptr) { |
| 115 | + continue; |
| 116 | + } |
| 117 | + // Only rewrite PrimFuncs with attr "layout_free_buffers" |
| 118 | + Array<Integer> layout_free_buffer_index = |
| 119 | + prim_func->GetAttr(attr::layout_free_buffers, Array<Integer>()).value(); |
| 120 | + |
| 121 | + Array<Buffer> layout_free_buffers; |
| 122 | + for (const Integer& index : layout_free_buffer_index) { |
| 123 | + const Var& param = prim_func->params[index->value]; |
| 124 | + layout_free_buffers.push_back(prim_func->buffer_map.at(param)); |
| 125 | + } |
| 126 | + // Collect Buffer read positions |
| 127 | + BufferReadPosCollector collector(layout_free_buffers); |
| 128 | + collector(prim_func->body); |
| 129 | + const auto& locations = collector.GetBufferLocations(); |
| 130 | + const auto& index_maps = collector.GetBufferIndexMap(); |
| 131 | + // Check all buffers are collected |
| 132 | + if (locations.size() != layout_free_buffers.size() || |
| 133 | + index_maps.size() != layout_free_buffer_index.size()) { |
| 134 | + return false; |
| 135 | + } |
| 136 | + |
| 137 | + for (const auto& kv : locations) { |
| 138 | + const Buffer& buffer = GetRef<Buffer>(kv.first); |
| 139 | + const Block& block = kv.second.first; |
| 140 | + int buffer_index = kv.second.second; |
| 141 | + |
| 142 | + // Get IndexMap |
| 143 | + const Optional<IndexMap> index_map = index_maps.at(buffer.get()); |
| 144 | + if (!index_map.defined()) { |
| 145 | + continue; |
| 146 | + } |
| 147 | + |
| 148 | + // Apply schedule |
| 149 | + BlockRV block_rv = sch->GetBlock(block->name_hint, func_name); |
| 150 | + BlockRV cached_block_rv = sch->CacheRead(block_rv, buffer_index, "global"); |
| 151 | + sch->TransformLayout(block_rv, buffer_index, BufferIndexType::kRead, index_map.value()); |
| 152 | + sch->Annotate(cached_block_rv, attr::meta_schedule_layout_rewrite_preproc, const_true()); |
| 153 | + } |
| 154 | + } |
| 155 | + return true; |
| 156 | +} |
| 157 | + |
| 158 | +} // namespace tir |
| 159 | + |
| 160 | +namespace meta_schedule { |
| 161 | +/*! \brief Layout Rewrite. */ |
| 162 | +class RewriteLayoutNode : public PostprocNode { |
| 163 | + public: |
| 164 | + // Inherited from PostprocNode |
| 165 | + void InitializeWithTuneContext(const TuneContext& context) final {} |
| 166 | + |
| 167 | + // Inherited from PostprocNode |
| 168 | + bool Apply(const tir::Schedule& sch) final { return tir::RewriteLayout(sch); } |
| 169 | + |
| 170 | + static constexpr const char* _type_key = "meta_schedule.RewriteLayout"; |
| 171 | + TVM_DECLARE_FINAL_OBJECT_INFO(RewriteLayoutNode, PostprocNode); |
| 172 | +}; |
| 173 | + |
| 174 | +Postproc Postproc::RewriteLayout() { |
| 175 | + auto n = make_object<RewriteLayoutNode>(); |
| 176 | + return Postproc(n); |
| 177 | +} |
| 178 | + |
| 179 | +TVM_REGISTER_NODE_TYPE(RewriteLayoutNode); |
| 180 | +TVM_REGISTER_GLOBAL("meta_schedule.PostprocRewriteLayout").set_body_typed(Postproc::RewriteLayout); |
| 181 | + |
| 182 | +} // namespace meta_schedule |
| 183 | +} // namespace tvm |
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