//===- ReduceFunctions.cpp - Specialized Delta Pass -----------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file implements a function which calls the Generic Delta pass in order // to reduce functions (and any instruction that calls it) in the provided // Module. // //===----------------------------------------------------------------------===// #include "ReduceFunctions.h" #include "Delta.h" #include "llvm/ADT/STLExtras.h" #include "llvm/IR/Instructions.h" #include <iterator> #include <vector> using namespace llvm; /// Removes all the Defined Functions /// that aren't inside any of the desired Chunks. static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep, Module *Program) { Oracle O(ChunksToKeep); // Record all out-of-chunk functions. std::vector<std::reference_wrapper<Function>> FuncsToRemove; copy_if(Program->functions(), std::back_inserter(FuncsToRemove), [&O](Function &F) { // Intrinsics don't have function bodies that are useful to // reduce. Additionally, intrinsics may have additional operand // constraints. But, do drop intrinsics that are not referenced. return (!F.isIntrinsic() || F.use_empty()) && !O.shouldKeep(); }); // Then, drop body of each of them. We want to batch this and do nothing else // here so that minimal number of remaining exteranal uses will remain. for (Function &F : FuncsToRemove) F.dropAllReferences(); // And finally, we can actually delete them. for (Function &F : FuncsToRemove) { // Replace all *still* remaining uses with undef. F.replaceAllUsesWith(UndefValue::get(F.getType())); // And finally, fully drop it. F.eraseFromParent(); } } /// Counts the amount of functions and prints their /// respective name & index static int countFunctions(Module *Program) { // TODO: Silence index with --quiet flag errs() << "----------------------------\n"; errs() << "Function Index Reference:\n"; int FunctionCount = 0; for (auto &F : *Program) { if (F.isIntrinsic() && !F.use_empty()) continue; errs() << '\t' << ++FunctionCount << ": " << F.getName() << '\n'; } errs() << "----------------------------\n"; return FunctionCount; } void llvm::reduceFunctionsDeltaPass(TestRunner &Test) { errs() << "*** Reducing Functions...\n"; int Functions = countFunctions(Test.getProgram()); runDeltaPass(Test, Functions, extractFunctionsFromModule); errs() << "----------------------------\n"; } |