| //===- ReduceGlobalVars.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 initialized Global Variables in the provided Module. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ReduceGlobalVars.h" |
| #include <set> |
| |
| using namespace llvm; |
| |
| /// Removes all the Initialized GVs that aren't inside the desired Chunks. |
| static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep, |
| Module *Program) { |
| // Get GVs inside desired chunks |
| std::set<GlobalVariable *> GVsToKeep; |
| int I = 0, GVCount = 0; |
| for (auto &GV : Program->globals()) |
| if (GV.hasInitializer() && I < (int)ChunksToKeep.size()) { |
| if (ChunksToKeep[I].contains(++GVCount)) |
| GVsToKeep.insert(&GV); |
| if (GVCount == ChunksToKeep[I].end) |
| ++I; |
| } |
| |
| // Delete out-of-chunk GVs and their uses |
| std::vector<GlobalVariable *> ToRemove; |
| std::vector<Instruction *> InstToRemove; |
| for (auto &GV : Program->globals()) |
| if (GV.hasInitializer() && !GVsToKeep.count(&GV)) { |
| for (auto U : GV.users()) |
| if (auto *Inst = dyn_cast<Instruction>(U)) |
| InstToRemove.push_back(Inst); |
| |
| GV.replaceAllUsesWith(UndefValue::get(GV.getType())); |
| ToRemove.push_back(&GV); |
| } |
| |
| // Delete Instruction uses of unwanted GVs |
| for (auto *Inst : InstToRemove) { |
| Inst->replaceAllUsesWith(UndefValue::get(Inst->getType())); |
| Inst->eraseFromParent(); |
| } |
| |
| for (auto *GV : ToRemove) |
| GV->eraseFromParent(); |
| } |
| |
| /// Counts the amount of initialized GVs and displays their |
| /// respective name & index |
| static int countGVs(Module *Program) { |
| // TODO: Silence index with --quiet flag |
| outs() << "----------------------------\n"; |
| outs() << "GlobalVariable Index Reference:\n"; |
| int GVCount = 0; |
| for (auto &GV : Program->globals()) |
| if (GV.hasInitializer()) |
| outs() << "\t" << ++GVCount << ": " << GV.getName() << "\n"; |
| outs() << "----------------------------\n"; |
| return GVCount; |
| } |
| |
| void llvm::reduceGlobalsDeltaPass(TestRunner &Test) { |
| outs() << "*** Reducing GVs...\n"; |
| int GVCount = countGVs(Test.getProgram()); |
| runDeltaPass(Test, GVCount, extractGVsFromModule); |
| } |