| /* Copyright 2019 The TensorFlow Authors. All Rights Reserved. |
| |
| 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. |
| ==============================================================================*/ |
| |
| #include "llvm/Support/Debug.h" |
| #include "mlir/Dialect/Func/IR/FuncOps.h" // from @llvm-project |
| #include "mlir/IR/Builders.h" // from @llvm-project |
| #include "mlir/IR/Operation.h" // from @llvm-project |
| #include "mlir/Pass/Pass.h" // from @llvm-project |
| #include "mlir/Pass/PassRegistry.h" // from @llvm-project |
| #include "tensorflow/compiler/mlir/tensorflow/ir/tf_executor.h" |
| #include "tensorflow/compiler/mlir/tensorflow/transforms/passes_detail.h" |
| |
| #define DEBUG_TYPE "tf-functional-to-executor" |
| |
| namespace mlir { |
| |
| namespace { |
| // This pass converts mlir functions consisting of mlir ops into a tf_executor |
| // dialect as a single island. |
| // Result like so: |
| // func @my_fn(%argi...) -> (result_t) { |
| // %results:[[n_args]] = tf_executor.graph { |
| // %island_results:[[nargs + 1]] = tf_executor.island { |
| // ... original ops ... |
| // tf_executor.yield %results... |
| // } |
| // tf_executor.fetch %island_results#... |
| // } |
| // return %graph_results#... |
| // } |
| struct FunctionalToExecutorDialectConversion |
| : public TF::FunctionalToExecutorDialectConversionPassBase< |
| FunctionalToExecutorDialectConversion> { |
| void runOnOperation() override; |
| }; |
| } // end anonymous namespace |
| |
| void FunctionalToExecutorDialectConversion::runOnOperation() { |
| auto func = getOperation(); |
| if (func.isExternal()) return; |
| if (!llvm::hasSingleElement(func)) { |
| LLVM_DEBUG(llvm::dbgs() << "Expect single block function, skip conversion " |
| "to tf_executor dialect\n"); |
| return; |
| } |
| auto loc = func.getLoc(); |
| mlir::Block& body = func.front(); |
| // Find region of interest and ReturnOp. |
| auto copy_range = body.without_terminator(); |
| if (copy_range.begin() != copy_range.end() && |
| std::next(copy_range.begin()) == copy_range.end() && |
| isa<tf_executor::GraphOp>(*copy_range.begin())) { |
| // Already a graph. |
| return; |
| } |
| |
| auto return_op = dyn_cast<func::ReturnOp>(body.getTerminator()); |
| if (!return_op) { |
| LLVM_DEBUG(llvm::dbgs() << "Expect function to end with return\n"); |
| return; |
| } |
| // Build GraphOp. |
| OpBuilder builder(&body, body.begin()); |
| auto graph_op = builder.create<tf_executor::GraphOp>( |
| loc, func.getFunctionType().getResults()); |
| graph_op.body().push_back(new Block); |
| builder.setInsertionPointToEnd(&graph_op.GetBody()); |
| auto island = builder.create<tf_executor::IslandOp>( |
| loc, func.getFunctionType().getResults(), |
| tf_executor::ControlType::get(&getContext()), ArrayRef<Value>()); |
| // Create Fetch. |
| ValueRange to_fetch = island.getResults(); |
| if (to_fetch.size() != 1) { |
| // Drop control result for fetch. |
| to_fetch = to_fetch.drop_back(); |
| } |
| builder.create<tf_executor::FetchOp>(loc, to_fetch); |
| // Build Island. |
| island.body().push_back(new Block); |
| island.body().front().getOperations().splice( |
| island.body().front().begin(), body.getOperations(), copy_range.begin(), |
| copy_range.end()); |
| builder.setInsertionPointToEnd(&island.body().front()); |
| builder.create<tf_executor::YieldOp>(loc, return_op.getOperands()); |
| for (auto item : llvm::enumerate(graph_op.getResults())) { |
| return_op.setOperand(item.index(), item.value()); |
| } |
| } |
| |
| std::unique_ptr<OperationPass<func::FuncOp>> |
| CreateFunctionalToExecutorDialectConversionPass() { |
| return std::make_unique<FunctionalToExecutorDialectConversion>(); |
| } |
| |
| } // namespace mlir |