/* * Copyright 2018 WebAssembly Community Group participants * * 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. */ // // DataFlow IR is an SSA representation. It can be built from the main // Binaryen IR. // // THe main initial use case was an IR that could easily be converted to // Souper IR, and the design favors that. // #ifndef wasm_dataflow_users_h #define wasm_dataflow_users_h #include "dataflow/graph.h" namespace wasm { namespace DataFlow { // Calculates the users of each node. // users[x] = { y, z, .. } // where y, z etc. are nodes that use x, that is, x is in their // values vector. class Users { typedef std::unordered_set UserSet; std::unordered_map users; public: void build(Graph& graph) { for (auto& node : graph.nodes) { for (auto* value : node->values) { users[value].insert(node.get()); } } } UserSet& getUsers(Node* node) { auto iter = users.find(node); if (iter == users.end()) { static UserSet empty; // FIXME thread_local? return empty; } return iter->second; } Index getNumUses(Node* node) { auto& users = getUsers(node); // A user may have more than one use Index numUses = 0; for (auto* user : users) { #ifndef NDEBUG bool found = false; #endif for (auto* value : user->values) { if (value == node) { numUses++; #ifndef NDEBUG found = true; #endif } } assert(found); } return numUses; } // Stops using all the values of this node. Called when a node is being // removed. void stopUsingValues(Node* node) { for (auto* value : node->values) { auto& users = getUsers(value); users.erase(node); } } // Adds a new user to a node. Called when we add or change a value of a node. void addUser(Node* node, Node* newUser) { users[node].insert(newUser); } // Remove all uses of a node. Called when a node is being removed. void removeAllUsesOf(Node* node) { users.erase(node); } }; } // namespace DataFlow } // namespace wasm #endif // wasm_dataflow_users