| //===- ReduceSpecialGlobals.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 special globals, like @llvm.used, in the provided Module. |
| // |
| // For more details about special globals, see |
| // https://llvm.org/docs/LangRef.html#intrinsic-global-variables |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ReduceSpecialGlobals.h" |
| #include "Delta.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/GlobalValue.h" |
| |
| using namespace llvm; |
| |
| static StringRef SpecialGlobalNames[] = {"llvm.used", "llvm.compiler.used"}; |
| |
| /// Removes all special globals aren't inside any of the |
| /// desired Chunks. |
| static void |
| extractSpecialGlobalsFromModule(const std::vector<Chunk> &ChunksToKeep, |
| Module *Program) { |
| Oracle O(ChunksToKeep); |
| |
| for (StringRef Name : SpecialGlobalNames) { |
| if (auto *Used = Program->getNamedGlobal(Name)) { |
| Used->replaceAllUsesWith(UndefValue::get(Used->getType())); |
| Used->eraseFromParent(); |
| } |
| } |
| } |
| |
| /// Counts the amount of special globals and prints their |
| /// respective name & index |
| static int countSpecialGlobals(Module *Program) { |
| // TODO: Silence index with --quiet flag |
| errs() << "----------------------------\n"; |
| errs() << "Special Globals Index Reference:\n"; |
| int Count = 0; |
| for (StringRef Name : SpecialGlobalNames) { |
| if (auto *Used = Program->getNamedGlobal(Name)) |
| errs() << "\t" << ++Count << ": " << Used->getName() << "\n"; |
| } |
| errs() << "----------------------------\n"; |
| return Count; |
| } |
| |
| void llvm::reduceSpecialGlobalsDeltaPass(TestRunner &Test) { |
| errs() << "*** Reducing Special Globals ...\n"; |
| int Functions = countSpecialGlobals(Test.getProgram()); |
| runDeltaPass(Test, Functions, extractSpecialGlobalsFromModule); |
| errs() << "----------------------------\n"; |
| } |