| /* 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 <queue> |
| #include <string> |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SetVector.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "mlir/Dialect/Func/IR/FuncOps.h" // from @llvm-project |
| #include "mlir/IR/Builders.h" // from @llvm-project |
| #include "mlir/IR/BuiltinOps.h" // from @llvm-project |
| #include "mlir/IR/Location.h" // from @llvm-project |
| #include "mlir/IR/MLIRContext.h" // from @llvm-project |
| #include "mlir/IR/SymbolTable.h" // from @llvm-project |
| #include "mlir/Pass/Pass.h" // from @llvm-project |
| #include "tensorflow/compiler/mlir/lite/transforms/passes.h" |
| |
| // The cmd line flag to specify the allowlist of functions. Rest are trimmed |
| // after this pass is run. |
| // NOLINTNEXTLINE |
| static llvm::cl::list<std::string> trim_funcs_allowlist( |
| "tfl-trim-funcs-allowlist", llvm::cl::value_desc("list"), |
| llvm::cl::desc("comma separated list of allowlisted functions. The first " |
| "function specified will be used as main."), |
| llvm::cl::CommaSeparated); |
| |
| namespace mlir { |
| namespace TFL { |
| namespace { |
| |
| // The pass to trim functions before we legalize to TFL |
| // dialect using the specified allowlist. |
| class TrimFunctionsPass |
| : public mlir::PassWrapper<TrimFunctionsPass, OperationPass<ModuleOp>> { |
| public: |
| MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TrimFunctionsPass) |
| |
| explicit TrimFunctionsPass() : trim_funcs_allowlist_(trim_funcs_allowlist) {} |
| explicit TrimFunctionsPass(llvm::ArrayRef<std::string> trim_funcs_allowlist) |
| : trim_funcs_allowlist_(trim_funcs_allowlist) {} |
| |
| StringRef getArgument() const final { |
| // This is the argument used to refer to the pass in |
| // the textual format (on the commandline for example). |
| return "tfl-trim-funcs-tf"; |
| } |
| StringRef getDescription() const final { |
| // This is a brief description of the pass. |
| return "Trim functions to restrict them to a specified allowlist prior to " |
| "legalization to TensorFlow lite dialect"; |
| } |
| |
| private: |
| void runOnOperation() override; |
| bool TrimModule(); |
| void Verify(); |
| |
| llvm::ArrayRef<std::string> trim_funcs_allowlist_; |
| }; |
| |
| void TrimFunctionsPass::runOnOperation() { |
| // trim the functions in the module using the trim_funcs_allowlist_ |
| // by removing functions not in the allowlist. |
| if (TrimModule()) { |
| // verify the updated module is still valid, if not signal the |
| // pass as failed. |
| Verify(); |
| } |
| } |
| |
| bool TrimFunctionsPass::TrimModule() { |
| // if no trim_funcs_allowlist_ is specified, this pass is a no-op. |
| if (trim_funcs_allowlist_.empty()) return false; |
| |
| llvm::SmallVector<func::FuncOp, 4> funcs_to_trim; |
| for (auto func : getOperation().getOps<func::FuncOp>()) { |
| if (llvm::is_contained(trim_funcs_allowlist_, func.getName())) { |
| // If no main is specified in the allowlist, use the 1st func |
| // in trim_funcs_allowlist as the main. |
| // TODO(ashwinm): Currently tflite flatbuffer export assumes there is |
| // always a main. This is strictly not required for TFlite. We need to |
| // remove that restriction once we have support to attribute the main |
| // tensorflow function in MLIR TF import using an entry_point attr. |
| if (!llvm::is_contained(trim_funcs_allowlist_, "main") && |
| func.getName() == trim_funcs_allowlist_[0]) { |
| func.setName(StringAttr::get(func.getContext(), "main")); |
| } |
| } else { |
| funcs_to_trim.push_back(func); |
| } |
| } |
| |
| // remove all unexported functions from the module. |
| for (auto func : funcs_to_trim) { |
| func.erase(); |
| } |
| return true; |
| } |
| |
| // validate that all reachable functions from the remaining functions are |
| // also in the allowlist. |
| void TrimFunctionsPass::Verify() { |
| // TODO(ashwinm): Instead, we should make sure that references to all |
| // SymbolRefAttrs of all ops are present. |
| SymbolTable symbol_table = SymbolTable(getOperation()); |
| llvm::SetVector<func::FuncOp> reachable_funcs; |
| for (auto func : getOperation().getOps<func::FuncOp>()) { |
| auto walk_result = func.walk([&](func::CallOp op) -> WalkResult { |
| if (!symbol_table.lookup<func::FuncOp>(op.getCallee())) |
| return getOperation().emitError() |
| << func.getName() << " is not in the funcs allowlist"; |
| return WalkResult::advance(); |
| }); |
| if (walk_result.wasInterrupted()) return signalPassFailure(); |
| } |
| } |
| |
| } // namespace |
| |
| // Creates an instance of the TensorFlow Lite dialect TrimFunctions |
| /// pass. |
| std::unique_ptr<OperationPass<ModuleOp>> CreateTrimFunctionsPass( |
| llvm::ArrayRef<std::string> trim_funcs_allowlist) { |
| return std::make_unique<TrimFunctionsPass>(trim_funcs_allowlist); |
| } |
| |
| static PassRegistration<TrimFunctionsPass> pass; |
| |
| } // namespace TFL |
| } // namespace mlir |