1 //=== WebAssemblyNullifyDebugValueLists.cpp - Nullify DBG_VALUE_LISTs ---===// 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 /// \file 10 /// Nullify DBG_VALUE_LISTs instructions as a temporary measure before we 11 /// implement DBG_VALUE_LIST handling in WebAssemblyDebugValueManager. 12 /// See https://github.com/llvm/llvm-project/issues/49705. 13 /// TODO Correctly handle DBG_VALUE_LISTs 14 /// 15 //===----------------------------------------------------------------------===// 16 17 #include "WebAssembly.h" 18 #include "WebAssemblySubtarget.h" 19 #include "llvm/CodeGen/MachineFunctionPass.h" 20 using namespace llvm; 21 22 #define DEBUG_TYPE "wasm-nullify-dbg-value-lists" 23 24 namespace { 25 class WebAssemblyNullifyDebugValueLists final : public MachineFunctionPass { 26 StringRef getPassName() const override { 27 return "WebAssembly Nullify DBG_VALUE_LISTs"; 28 } 29 30 bool runOnMachineFunction(MachineFunction &MF) override; 31 32 public: 33 static char ID; // Pass identification, replacement for typeid 34 WebAssemblyNullifyDebugValueLists() : MachineFunctionPass(ID) {} 35 }; 36 } // end anonymous namespace 37 38 char WebAssemblyNullifyDebugValueLists::ID = 0; 39 INITIALIZE_PASS(WebAssemblyNullifyDebugValueLists, DEBUG_TYPE, 40 "WebAssembly Nullify DBG_VALUE_LISTs", false, false) 41 42 FunctionPass *llvm::createWebAssemblyNullifyDebugValueLists() { 43 return new WebAssemblyNullifyDebugValueLists(); 44 } 45 46 bool WebAssemblyNullifyDebugValueLists::runOnMachineFunction( 47 MachineFunction &MF) { 48 LLVM_DEBUG(dbgs() << "********** Nullify DBG_VALUE_LISTs **********\n" 49 "********** Function: " 50 << MF.getName() << '\n'); 51 bool Changed = false; 52 // Our backend, including WebAssemblyDebugValueManager, currently cannot 53 // handle DBG_VALUE_LISTs correctly. So this makes them undefined, which will 54 // appear as "optimized out". 55 for (auto &MBB : MF) { 56 for (auto &MI : MBB) { 57 if (MI.getOpcode() == TargetOpcode::DBG_VALUE_LIST) { 58 MI.setDebugValueUndef(); 59 Changed = true; 60 } 61 } 62 } 63 return Changed; 64 } 65