jroesch commented on a change in pull request #7765: URL: https://github.com/apache/tvm/pull/7765#discussion_r608061682
########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; Review comment: Could we maybe use `optional` or something else here? I feel like sentinel values unless really needed for some efficiency reason are not a great design as it requires users to remember special values. ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> Review comment: It feels like we should maybe introduce a WeakObject for these use cases? I can see having to duplicate a lot of functionality ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest Review comment: ```suggestion * - Parent sref: The parent reference of an sref is the block or loop reference to the closest schedulable statement. We define closest to be the nearest schedulable statement of an ancestor in the AST. ``` This could use some clarification. ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, + * which tracks the producer-consumer dependency between blocks. + * + * Glossary: + * - Block scope: A contiguous subtree of the sref tree, rooted at each block sref, + * whose components are: + * - scope root: a block sref + * - internal srefs: loop srefs + * - scope leaves: block srefs + * - Child block: The scope leaf blocks under the scope root or a specific internal sref + */ +class BlockScopeNode : public Object { + public: + /*! \brief Lookup table for the `src` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> src2deps; + /*! \brief Lookup table for the `dst` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> dst2deps; + /*! \brief The mapping from the buffer to the blocks who write it */ + std::unordered_map<Buffer, Array<StmtSRef>, ObjectPtrHash, ObjectPtrEqual> buffer_writers; + /*! + * \brief Property of a block scope root at the block, indicaiting if the scope is an equivalence Review comment: ```suggestion * \brief This property indicates that the block scope (rooted at its corresponding block) is equivalent to ``` ########## File path: include/tvm/tir/schedule/state.h ########## @@ -0,0 +1,216 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/state.h + * \brief This file defines ScheduleState, the core data structure of TensorIR scheduling. + */ +#ifndef TVM_TIR_SCHEDULE_STATE_H_ +#define TVM_TIR_SCHEDULE_STATE_H_ + +#include <tvm/ir/module.h> +#include <tvm/tir/function.h> +#include <tvm/tir/schedule/block_scope.h> + +#include <unordered_map> +#include <utility> + +namespace tvm { +namespace tir { + +/*! + * \brief The information about a TensorIR block, it contains two categories of information + * 1) Info on the block scope rooted at a specific block, including dependency tracking, + * flags indicating if the scope is a stage pipeline, etc. + * 2) Info on the block itself, including if the block has a quasi-affine binding, if the regions it + * reads are completely covered by their producers, etc. + */ +struct BlockInfo { + /*! \brief Property of a block scope rooted at the block, storing dependencies in the scope */ + BlockScope scope{nullptr}; + // The properties below are information about the current block realization under its parent scope + /*! \brief Property of a block, indicating the block realization binding is quasi-affine */ + bool affine_binding{false}; + /*! + * \brief Property of a block, indicating each of the block's read regions is fully + * produced by its producers + */ + bool region_cover{false}; + + BlockInfo() = default; + + explicit BlockInfo(BlockScope scope, bool affine_binding = false, bool region_cover = false) + : scope(std::move(scope)), // + affine_binding(affine_binding), // + region_cover(region_cover) {} +}; + +/*! + * \brief The bitmask of the debug flag in the ScheduleStateNode. + * \sa ScheduleStateNode + */ +enum class ScheduleDebugMask : int32_t { + /*! \brief Verify the correctness of the sref tree */ + kVerifySRefTree = 1, + /*! \brief Verify the correctness of affine_binding */ + kVerifyAffineBinding = 2, + /*! \brief Verify the correctness of region_cover */ + kVerifyRegionCover = 4, + /*! \brief Verify the correctness of stage_pipeline */ + kVerifyStagePipeline = 8, +}; + +/*! + * \brief The state of scheduling, which exposes a `Replace` method as + * the primary resort for all the scheduling primitives to manipulate the TensorIR. + * + * The data structure contains the following information + * 1) The AST being scheduled (mod) + * 2) The sref tree of schedulable statements (indicated by the srefs) + * 3) The dependency information of each block scope (block_info) + * 4) A reverse mapping from the AST nodes to that in the sref tree (stmt2ref) + * 5) A debug flag, if set, extra checking is enabled (debug_mode) + */ +class ScheduleStateNode : public Object { + public: + /*! \brief The AST of the module being scheduled */ + IRModule mod; + /*! + * \brief Mapping from a block sref to its correpsonding BlockInfo, + * tracking the dependency inside the block scope, + * and storing necessary information flags for scheduling + */ + std::unordered_map<StmtSRef, BlockInfo, ObjectPtrHash, ObjectPtrEqual> block_info; + /*! \brief The reverse mapping from block/for-loop to their corresponding srefs */ + std::unordered_map<const StmtNode*, StmtSRef> stmt2ref; + /*! + * \brief Do extra correctness checking after the class creation + * and each time after calling the Replace method. + * \sa ScheduleDebugMask + */ + int debug_mode; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("mod", &mod); + // `block_info` is not visited + // `stmt2ref` is not visited + v->Visit("debug_mode", &debug_mode); + } + /*! + * \brief Replace the part of the AST, as being pointed to by `src_sref`, Review comment: This is good example of a comment, thanks for this one! ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited Review comment: Is this because of the weak pointer optimization? It isn't clear why I can't read these fields ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to Review comment: ```suggestion * \brief The block or `for` stmt the object refers to ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. Review comment: Same comment as above, might be worth factoring this pattern out, I've seen this done multiple times. ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, Review comment: ```suggestion * \brief An object with 1-to-1 correspondence with each block reference in the sref tree. * This data structure is used to track the producer-consumer dependencies between blocks. * For example even leaf nodes have a scope node, even though they have no dependencies . ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by Review comment: It might be good to refer to the `sref` as `reference` in the english as repeating sref multiple times makes it much harder to read from my PoV. ########## File path: include/tvm/tir/schedule/state.h ########## @@ -0,0 +1,216 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/state.h + * \brief This file defines ScheduleState, the core data structure of TensorIR scheduling. + */ +#ifndef TVM_TIR_SCHEDULE_STATE_H_ +#define TVM_TIR_SCHEDULE_STATE_H_ + +#include <tvm/ir/module.h> +#include <tvm/tir/function.h> +#include <tvm/tir/schedule/block_scope.h> + +#include <unordered_map> +#include <utility> + +namespace tvm { +namespace tir { + +/*! + * \brief The information about a TensorIR block, it contains two categories of information + * 1) Info on the block scope rooted at a specific block, including dependency tracking, + * flags indicating if the scope is a stage pipeline, etc. + * 2) Info on the block itself, including if the block has a quasi-affine binding, if the regions it + * reads are completely covered by their producers, etc. + */ +struct BlockInfo { + /*! \brief Property of a block scope rooted at the block, storing dependencies in the scope */ + BlockScope scope{nullptr}; + // The properties below are information about the current block realization under its parent scope + /*! \brief Property of a block, indicating the block realization binding is quasi-affine */ + bool affine_binding{false}; + /*! + * \brief Property of a block, indicating each of the block's read regions is fully + * produced by its producers + */ + bool region_cover{false}; + + BlockInfo() = default; + + explicit BlockInfo(BlockScope scope, bool affine_binding = false, bool region_cover = false) + : scope(std::move(scope)), // + affine_binding(affine_binding), // + region_cover(region_cover) {} +}; + +/*! + * \brief The bitmask of the debug flag in the ScheduleStateNode. + * \sa ScheduleStateNode + */ +enum class ScheduleDebugMask : int32_t { + /*! \brief Verify the correctness of the sref tree */ + kVerifySRefTree = 1, + /*! \brief Verify the correctness of affine_binding */ + kVerifyAffineBinding = 2, + /*! \brief Verify the correctness of region_cover */ + kVerifyRegionCover = 4, + /*! \brief Verify the correctness of stage_pipeline */ + kVerifyStagePipeline = 8, +}; + +/*! + * \brief The state of scheduling, which exposes a `Replace` method as + * the primary resort for all the scheduling primitives to manipulate the TensorIR. Review comment: ```suggestion * the primary interface for all the scheduling primitives to manipulate the TensorIR. ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, + * which tracks the producer-consumer dependency between blocks. + * + * Glossary: + * - Block scope: A contiguous subtree of the sref tree, rooted at each block sref, + * whose components are: + * - scope root: a block sref + * - internal srefs: loop srefs + * - scope leaves: block srefs + * - Child block: The scope leaf blocks under the scope root or a specific internal sref + */ +class BlockScopeNode : public Object { + public: + /*! \brief Lookup table for the `src` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> src2deps; + /*! \brief Lookup table for the `dst` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> dst2deps; + /*! \brief The mapping from the buffer to the blocks who write it */ + std::unordered_map<Buffer, Array<StmtSRef>, ObjectPtrHash, ObjectPtrEqual> buffer_writers; + /*! + * \brief Property of a block scope root at the block, indicaiting if the scope is an equivalence + * of a stage pipeline. Conditions: Review comment: ```suggestion * a TVM/Halide stage pipeline. Under the following conditions: ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. Review comment: ```suggestion * - Block sref: A StmtSRef that points to a TensorIR block. ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, + * which tracks the producer-consumer dependency between blocks. Review comment: ```suggestion ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. Review comment: ```suggestion * - Loop sref: A StmtSRef that points to a TensorIR for loop. ``` ########## File path: python/tvm/tir/schedule/__init__.py ########## @@ -0,0 +1,21 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you 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. +# pylint: disable=unused-import +"""Namespace for TensorIR schedule.""" Review comment: ```suggestion """Namespace for the TensorIR schedule API.""" ``` ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, + * which tracks the producer-consumer dependency between blocks. + * + * Glossary: + * - Block scope: A contiguous subtree of the sref tree, rooted at each block sref, + * whose components are: + * - scope root: a block sref + * - internal srefs: loop srefs + * - scope leaves: block srefs + * - Child block: The scope leaf blocks under the scope root or a specific internal sref + */ +class BlockScopeNode : public Object { + public: + /*! \brief Lookup table for the `src` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> src2deps; + /*! \brief Lookup table for the `dst` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> dst2deps; + /*! \brief The mapping from the buffer to the blocks who write it */ + std::unordered_map<Buffer, Array<StmtSRef>, ObjectPtrHash, ObjectPtrEqual> buffer_writers; + /*! + * \brief Property of a block scope root at the block, indicaiting if the scope is an equivalence + * of a stage pipeline. Conditions: + * 1) The region cover property holds for every of its child blocks + * 2) No write-after-read dependency + */ + bool stage_pipeline{false}; + + void VisitAttrs(AttrVisitor* v) {} + + static constexpr const char* _type_key = "tir.BlockScope"; + TVM_DECLARE_FINAL_OBJECT_INFO(BlockScopeNode, Object); + + public: + /******** Dependency ********/ + /*! + * \brief Get all dependencies whose `src` equals `src` + * \param src The queried block + * \return The dependencies + */ + TVM_DLL Array<Dependency> GetDepsBySrc(const StmtSRef& src) const; + /*! + * \brief Get all dependencies whose `dst` equals `dst` + * \param dst The queried block + * \return The dependencies + */ + TVM_DLL Array<Dependency> GetDepsByDst(const StmtSRef& dst) const; +}; + +/*! + * \brief Managed reference to BlockScopeNode + * \sa BlockScopeNode + */ +class BlockScope : public ObjectRef { + public: + /*! \brief The constructor creating an empty block scope with on dependency information */ + TVM_DLL BlockScope(); + /*! + * \brief Create the object with the specific leaf blocks, and complete the dependency information Review comment: By complete do you mean, compute the dependency info then store it? ########## File path: include/tvm/tir/schedule/state.h ########## @@ -0,0 +1,216 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/state.h + * \brief This file defines ScheduleState, the core data structure of TensorIR scheduling. + */ +#ifndef TVM_TIR_SCHEDULE_STATE_H_ +#define TVM_TIR_SCHEDULE_STATE_H_ + +#include <tvm/ir/module.h> +#include <tvm/tir/function.h> +#include <tvm/tir/schedule/block_scope.h> + +#include <unordered_map> +#include <utility> + +namespace tvm { +namespace tir { + +/*! + * \brief The information about a TensorIR block, it contains two categories of information + * 1) Info on the block scope rooted at a specific block, including dependency tracking, + * flags indicating if the scope is a stage pipeline, etc. + * 2) Info on the block itself, including if the block has a quasi-affine binding, if the regions it + * reads are completely covered by their producers, etc. + */ +struct BlockInfo { + /*! \brief Property of a block scope rooted at the block, storing dependencies in the scope */ + BlockScope scope{nullptr}; + // The properties below are information about the current block realization under its parent scope + /*! \brief Property of a block, indicating the block realization binding is quasi-affine */ + bool affine_binding{false}; + /*! + * \brief Property of a block, indicating each of the block's read regions is fully + * produced by its producers + */ + bool region_cover{false}; + + BlockInfo() = default; + + explicit BlockInfo(BlockScope scope, bool affine_binding = false, bool region_cover = false) + : scope(std::move(scope)), // + affine_binding(affine_binding), // + region_cover(region_cover) {} +}; + +/*! + * \brief The bitmask of the debug flag in the ScheduleStateNode. + * \sa ScheduleStateNode + */ +enum class ScheduleDebugMask : int32_t { + /*! \brief Verify the correctness of the sref tree */ + kVerifySRefTree = 1, + /*! \brief Verify the correctness of affine_binding */ + kVerifyAffineBinding = 2, + /*! \brief Verify the correctness of region_cover */ + kVerifyRegionCover = 4, + /*! \brief Verify the correctness of stage_pipeline */ + kVerifyStagePipeline = 8, +}; + +/*! + * \brief The state of scheduling, which exposes a `Replace` method as + * the primary resort for all the scheduling primitives to manipulate the TensorIR. Review comment: Not sure about this one ########## File path: include/tvm/tir/schedule/block_scope.h ########## @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ +/*! + * \file tvm/tir/schedule/block_scope.h + * \brief Definition of two pillar data structure for TensorIR scheduling: StmtSRef, BlockScope. + * \sa StmtSRefNode + * \sa BlockScopeNode + */ +#ifndef TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ +#define TVM_TIR_SCHEDULE_BLOCK_SCOPE_H_ + +#include <tvm/tir/stmt.h> + +#include <unordered_map> + +namespace tvm { +namespace tir { + +/*! + * \brief An object that refers to schedulable elements (block/for-loop) in TensorIR, aka "sref". + * + * Glossary + * - Block sref: An StmtSRef that points to a TensorIR block. + * - Loop sref: An StmtSRef that points to a TensorIR for loop. + * - Parent sref: The parent sref of an sref is the block/loop sref that points to its closest + * schedulable statement of its ancestors on the TensorIR AST. + * - Root sref: Sref to the root block. Every sref has exactly one parent sref except for root sref. + * - Sref tree: The parent-children-relationship of srefs that forms a tree, uniquely determined by + * the TensorIR AST. + */ +class StmtSRefNode : public Object { + public: + /*! + * \brief The block/for stmt the object refers to + * \note Non-owned reference (raw pointer) is used here, so that we can perform copy-on-write + * optimization on statements when possible. The strong reference is held in the ScheduleState. + */ + const StmtNode* stmt; + /*! \brief The parent sref. */ + StmtSRefNode* parent; + /*! + * \brief If the statement the sref points to is an element of a SeqStmt in the AST, + * then `seq_index` is set to its index; otherwise `seq_index` is -1 + */ + int64_t seq_index; + + void VisitAttrs(AttrVisitor* v) { + // `stmt` is not visited + // `parent` is not visited + v->Visit("seq_index", &seq_index); + } + + static constexpr const char* _type_key = "tir.StmtSRef"; + TVM_DECLARE_FINAL_OBJECT_INFO(StmtSRefNode, Object); + + /*! \brief Reset the object inplace to the invalid state */ + void Reset() { + this->stmt = nullptr; + this->parent = nullptr; + this->seq_index = -1; + } + + /*! + * \brief Get the referenced statement with proper type checking. + * It serves the same purpose as `ObjectRef::as`, but does not acquire strong reference to `stmt` + * \tparam StmtType The type that `this->stmt` to be downcasted to. Presumably + * tvm::tir::BlockNode or tvm::tir::ForNode + * \return nullptr if type check fails, otherwise the casted result for `this->stmt` + */ + template <typename StmtType> + const StmtType* StmtAs() const { + if (stmt != nullptr && stmt->IsInstance<StmtType>()) { + return static_cast<const StmtType*>(stmt); + } else { + return nullptr; + } + } +}; + +/*! + * \brief Managed reference to StmtSRefNode + * \sa StmtSRefNode + */ +class StmtSRef : public ObjectRef { + public: + /*! + * \brief The constructor + * \param stmt The corresponding stmt node, can be either block or for loop. + * \param parent The parent sref. + * \param seq_index The location in an array if the parent of the stmt contains multiple children. + * -1 if the parent does not contain multiple children. + */ + TVM_DLL explicit StmtSRef(const StmtNode* stmt, StmtSRefNode* parent, int64_t seq_index); + + /*! \return The mutable pointer to the StmtSRefNode */ + StmtSRefNode* get() const { return static_cast<StmtSRefNode*>(data_.get()); } + + TVM_DEFINE_MUTABLE_OBJECT_REF_METHODS(StmtSRef, ObjectRef, StmtSRefNode); + + public: + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do the work of compute-inline + */ + TVM_DLL static StmtSRef InlineMark(); + /*! + * \return A special StmtSRef, which doesn't point to any stmt in the AST, + * only serving as a "mark" to hint compute-at to do nothing + */ + TVM_DLL static StmtSRef RootMark(); +}; + +/*! + * \brief Type of dependency. Right now we have 4 types of dependencies + * 1) Read-after-write (kRAW) + * 2) Write-after-write (kWAW) + * 3) Write-after-read (kWAR) + * 4) Opaque dependency (kOpaque) + */ +enum class DepKind : int32_t { + kRAW = 0, + kWAW = 1, + kWAR = 2, + kOpaque = 3, +}; + +/*! + * \brief A tuple (src, dst, kind) representing certain types of dependency. + * For example, (A, B, kRAW) means block B depends on block A, and the dependency kind is + * read-after-write, which means block B reads the result written by block A. + */ +class DependencyNode : public Object { + public: + /*! \brief The source of the dependency relation */ + StmtSRef src; + /*! \brief The destination of the dependency relation */ + StmtSRef dst; + /*! \brief The dependency kind */ + DepKind kind; + + void VisitAttrs(AttrVisitor* v) { + v->Visit("src", &src); + v->Visit("dst", &dst); + v->Visit("kind", &kind); + } + + static constexpr const char* _type_key = "tir.Dependency"; + TVM_DECLARE_FINAL_OBJECT_INFO(DependencyNode, Object); +}; + +/*! + * \brief Managed reference to DependencyNode + * \sa DependencyNode + */ +class Dependency : public ObjectRef { + public: + /*! \brief Constructor */ + TVM_DLL explicit Dependency(StmtSRef src, StmtSRef dst, DepKind kind); + TVM_DEFINE_NOTNULLABLE_OBJECT_REF_METHODS(Dependency, ObjectRef, DependencyNode); +}; + +/*! + * \brief An object corresponds to each block sref in the sref tree, + * which tracks the producer-consumer dependency between blocks. + * + * Glossary: + * - Block scope: A contiguous subtree of the sref tree, rooted at each block sref, + * whose components are: + * - scope root: a block sref + * - internal srefs: loop srefs + * - scope leaves: block srefs + * - Child block: The scope leaf blocks under the scope root or a specific internal sref + */ +class BlockScopeNode : public Object { + public: + /*! \brief Lookup table for the `src` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> src2deps; + /*! \brief Lookup table for the `dst` of dependencies */ + std::unordered_map<StmtSRef, Array<Dependency>, ObjectPtrHash, ObjectPtrEqual> dst2deps; + /*! \brief The mapping from the buffer to the blocks who write it */ + std::unordered_map<Buffer, Array<StmtSRef>, ObjectPtrHash, ObjectPtrEqual> buffer_writers; Review comment: > We had been trying with `tvm::Map<Buffer, Array<StmtSRef>>` in the very beginning, but it turned out that we need the values (the `Array<StmtSRef>`) of the map to be mutable to make sure they are maintained properly during transformations, but with `tvm::Map` we are unable to do so in an easy way :-( Therefore, we have to provide workarounds like providing APIs `get_deps_by_src` on the python side. might be worth writing this down for future people in a NB -- This is an automated message from the Apache Git Service. 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