1 //===- ReduceFunctions.cpp - Specialized Delta Pass -----------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements a function which calls the Generic Delta pass in order 10 // to reduce functions (and any instruction that calls it) in the provided 11 // Module. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "ReduceFunctions.h" 16 #include "Delta.h" 17 18 using namespace llvm; 19 20 /// Removes all the Defined Functions (as well as their calls) 21 /// that aren't inside any of the desired Chunks. 22 static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep, 23 Module *Program) { 24 // Get functions inside desired chunks 25 std::set<Function *> FuncsToKeep; 26 unsigned I = 0, FunctionCount = 0; 27 for (auto &F : *Program) 28 if (I < ChunksToKeep.size()) { 29 if (ChunksToKeep[I].contains(++FunctionCount)) 30 FuncsToKeep.insert(&F); 31 if (FunctionCount == ChunksToKeep[I].end) 32 ++I; 33 } 34 35 // Delete out-of-chunk functions, and replace their calls with undef 36 std::vector<Function *> FuncsToRemove; 37 std::vector<CallInst *> CallsToRemove; 38 for (auto &F : *Program) 39 if (!FuncsToKeep.count(&F)) { 40 for (auto U : F.users()) 41 if (auto *Call = dyn_cast<CallInst>(U)) { 42 Call->replaceAllUsesWith(UndefValue::get(Call->getType())); 43 CallsToRemove.push_back(Call); 44 } 45 F.replaceAllUsesWith(UndefValue::get(F.getType())); 46 FuncsToRemove.push_back(&F); 47 } 48 49 for (auto *C : CallsToRemove) 50 C->eraseFromParent(); 51 52 for (auto *F : FuncsToRemove) 53 F->eraseFromParent(); 54 } 55 56 /// Counts the amount of non-declaration functions and prints their 57 /// respective name & index 58 static unsigned countFunctions(Module *Program) { 59 // TODO: Silence index with --quiet flag 60 errs() << "----------------------------\n"; 61 errs() << "Function Index Reference:\n"; 62 unsigned FunctionCount = 0; 63 for (auto &F : *Program) 64 errs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n"; 65 66 errs() << "----------------------------\n"; 67 return FunctionCount; 68 } 69 70 void llvm::reduceFunctionsDeltaPass(TestRunner &Test) { 71 errs() << "*** Reducing Functions...\n"; 72 unsigned Functions = countFunctions(Test.getProgram()); 73 runDeltaPass(Test, Functions, extractFunctionsFromModule); 74 errs() << "----------------------------\n"; 75 } 76