97 lines · cpp
1//===-- ResetMachineFunctionPass.cpp - Reset Machine Function ----*- C++ -*-==//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-exception6//7//===----------------------------------------------------------------------===//8/// \file9/// This file implements a pass that will conditionally reset a machine10/// function as if it was just created. This is used to provide a fallback11/// mechanism when GlobalISel fails, thus the condition for the reset to12/// happen is that the MachineFunction has the FailedISel property.13//===----------------------------------------------------------------------===//14 15#include "llvm/ADT/ScopeExit.h"16#include "llvm/ADT/Statistic.h"17#include "llvm/CodeGen/MachineFunction.h"18#include "llvm/CodeGen/MachineFunctionPass.h"19#include "llvm/CodeGen/MachineRegisterInfo.h"20#include "llvm/CodeGen/Passes.h"21#include "llvm/CodeGen/StackProtector.h"22#include "llvm/IR/DiagnosticInfo.h"23#include "llvm/InitializePasses.h"24#include "llvm/Support/Debug.h"25#include "llvm/Target/TargetMachine.h"26using namespace llvm;27 28#define DEBUG_TYPE "reset-machine-function"29 30STATISTIC(NumFunctionsReset, "Number of functions reset");31STATISTIC(NumFunctionsVisited, "Number of functions visited");32 33namespace {34 class ResetMachineFunction : public MachineFunctionPass {35 /// Tells whether or not this pass should emit a fallback36 /// diagnostic when it resets a function.37 bool EmitFallbackDiag;38 /// Whether we should abort immediately instead of resetting the function.39 bool AbortOnFailedISel;40 41 public:42 static char ID; // Pass identification, replacement for typeid43 ResetMachineFunction(bool EmitFallbackDiag = false,44 bool AbortOnFailedISel = false)45 : MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag),46 AbortOnFailedISel(AbortOnFailedISel) {}47 48 StringRef getPassName() const override { return "ResetMachineFunction"; }49 50 void getAnalysisUsage(AnalysisUsage &AU) const override {51 AU.addPreserved<StackProtector>();52 MachineFunctionPass::getAnalysisUsage(AU);53 }54 55 bool runOnMachineFunction(MachineFunction &MF) override {56 ++NumFunctionsVisited;57 // No matter what happened, whether we successfully selected the function58 // or not, nothing is going to use the vreg types after us. Make sure they59 // disappear.60 auto ClearVRegTypesOnReturn =61 make_scope_exit([&MF]() { MF.getRegInfo().clearVirtRegTypes(); });62 63 if (MF.getProperties().hasFailedISel()) {64 if (AbortOnFailedISel)65 report_fatal_error("Instruction selection failed");66 LLVM_DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');67 ++NumFunctionsReset;68 MF.reset();69 MF.initTargetMachineFunctionInfo(MF.getSubtarget());70 71 const TargetMachine &TM = MF.getTarget();72 // MRI callback for target specific initializations.73 TM.registerMachineRegisterInfoCallback(MF);74 75 if (EmitFallbackDiag) {76 const Function &F = MF.getFunction();77 DiagnosticInfoISelFallback DiagFallback(F);78 F.getContext().diagnose(DiagFallback);79 }80 return true;81 }82 return false;83 }84 85 };86} // end anonymous namespace87 88char ResetMachineFunction::ID = 0;89INITIALIZE_PASS(ResetMachineFunction, DEBUG_TYPE,90 "Reset machine function if ISel failed", false, false)91 92MachineFunctionPass *93llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false,94 bool AbortOnFailedISel = false) {95 return new ResetMachineFunction(EmitFallbackDiag, AbortOnFailedISel);96}97