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 17 /// Removes all the Defined Functions (as well as their calls) 18 /// that aren't inside any of the desired Chunks. 19 /// @returns the Module stripped of out-of-chunk functions 20 static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep, 21 Module *Program) { 22 // Get functions inside desired chunks 23 std::set<Function *> FuncsToKeep; 24 unsigned I = 0, FunctionCount = 0; 25 for (auto &F : *Program) { 26 if (!F.isDeclaration() && I < ChunksToKeep.size()) { 27 if (ChunksToKeep[I].contains(++FunctionCount)) 28 FuncsToKeep.insert(&F); 29 if (FunctionCount == ChunksToKeep[I].end) 30 ++I; 31 } 32 } 33 34 // Delete out-of-chunk functions, and replace their calls with undef 35 std::vector<Function *> FuncsToRemove; 36 for (auto &F : *Program) { 37 if (!F.isDeclaration() && !FuncsToKeep.count(&F)) { 38 F.replaceAllUsesWith(UndefValue::get(F.getType())); 39 FuncsToRemove.push_back(&F); 40 } 41 } 42 for (auto *F : FuncsToRemove) 43 F->eraseFromParent(); 44 45 // Delete instructions with undef calls 46 std::vector<Instruction *> InstToRemove; 47 for (auto &F : *Program) 48 for (auto &BB : F) 49 for (auto &I : BB) 50 if (auto *Call = dyn_cast<CallInst>(&I)) 51 if (!Call->getCalledFunction()) { 52 // Instruction might be stored / used somewhere else 53 I.replaceAllUsesWith(UndefValue::get(I.getType())); 54 InstToRemove.push_back(&I); 55 } 56 57 for (auto *I : InstToRemove) 58 I->eraseFromParent(); 59 } 60 61 /// Counts the amount of non-declaration functions and prints their 62 /// respective name & index 63 static unsigned countDefinedFunctions(Module *Program) { 64 // TODO: Silence index with --quiet flag 65 outs() << "----------------------------\n"; 66 outs() << "Function Index Reference:\n"; 67 unsigned FunctionCount = 0; 68 for (auto &F : *Program) 69 if (!F.isDeclaration()) 70 outs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n"; 71 72 outs() << "----------------------------\n"; 73 return FunctionCount; 74 } 75 76 void llvm::reduceFunctionsDeltaPass(TestRunner &Test) { 77 outs() << "*** Reducing Functions...\n"; 78 unsigned Functions = countDefinedFunctions(Test.getProgram()); 79 runDeltaPass(Test, Functions, extractFunctionsFromModule); 80 }