| 1 | //===- ReduceInstructions.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 uninteresting Instructions from defined functions. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "ReduceInstructions.h" |
| 15 | #include "Utils.h" |
| 16 | #include "llvm/IR/Constants.h" |
| 17 | #include <set> |
| 18 | |
| 19 | using namespace llvm; |
| 20 | |
| 21 | /// Filter out cases where deleting the instruction will likely cause the |
| 22 | /// user/def of the instruction to fail the verifier. |
| 23 | // |
| 24 | // TODO: Technically the verifier only enforces preallocated token usage and |
| 25 | // there is a none token. |
| 26 | static bool shouldAlwaysKeep(const Instruction &I) { |
| 27 | return I.isEHPad() || I.getType()->isTokenTy() || I.isSwiftError(); |
| 28 | } |
| 29 | |
| 30 | /// Removes out-of-chunk arguments from functions, and modifies their calls |
| 31 | /// accordingly. It also removes allocations of out-of-chunk arguments. |
| 32 | static void extractInstrFromModule(Oracle &O, ReducerWorkItem &WorkItem) { |
| 33 | Module &Program = WorkItem.getModule(); |
| 34 | std::vector<Instruction *> InitInstToKeep; |
| 35 | |
| 36 | for (auto &F : Program) |
| 37 | for (auto &BB : F) { |
| 38 | // Removing the terminator would make the block invalid. Only iterate over |
| 39 | // instructions before the terminator. |
| 40 | InitInstToKeep.push_back(x: BB.getTerminator()); |
| 41 | for (auto &Inst : make_range(x: BB.begin(), y: std::prev(x: BB.end()))) { |
| 42 | if (shouldAlwaysKeep(I: Inst) || O.shouldKeep()) |
| 43 | InitInstToKeep.push_back(x: &Inst); |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | // We create a vector first, then convert it to a set, so that we don't have |
| 48 | // to pay the cost of rebalancing the set frequently if the order we insert |
| 49 | // the elements doesn't match the order they should appear inside the set. |
| 50 | std::set<Instruction *> InstToKeep(InitInstToKeep.begin(), |
| 51 | InitInstToKeep.end()); |
| 52 | |
| 53 | std::vector<Instruction *> InstToDelete; |
| 54 | for (auto &F : Program) |
| 55 | for (auto &BB : F) |
| 56 | for (auto &Inst : BB) |
| 57 | if (!InstToKeep.count(x: &Inst)) { |
| 58 | Inst.replaceAllUsesWith(V: getDefaultValue(T: Inst.getType())); |
| 59 | InstToDelete.push_back(x: &Inst); |
| 60 | } |
| 61 | |
| 62 | for (auto &I : InstToDelete) |
| 63 | I->eraseFromParent(); |
| 64 | } |
| 65 | |
| 66 | void llvm::reduceInstructionsDeltaPass(TestRunner &Test) { |
| 67 | runDeltaPass(Test, ExtractChunksFromModule: extractInstrFromModule, Message: "Reducing Instructions"); |
| 68 | } |
| 69 |