62 lines · cpp
1//===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===//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//9// This file implements basic block placement transformations which result in10// funclets being contiguous.11//12//===----------------------------------------------------------------------===//13#include "llvm/CodeGen/Analysis.h"14#include "llvm/CodeGen/MachineFunction.h"15#include "llvm/CodeGen/MachineFunctionPass.h"16#include "llvm/CodeGen/Passes.h"17#include "llvm/InitializePasses.h"18using namespace llvm;19 20#define DEBUG_TYPE "funclet-layout"21 22namespace {23class FuncletLayout : public MachineFunctionPass {24public:25 static char ID; // Pass identification, replacement for typeid26 FuncletLayout() : MachineFunctionPass(ID) {27 initializeFuncletLayoutPass(*PassRegistry::getPassRegistry());28 }29 30 bool runOnMachineFunction(MachineFunction &F) override;31 MachineFunctionProperties getRequiredProperties() const override {32 return MachineFunctionProperties().setNoVRegs();33 }34};35}36 37char FuncletLayout::ID = 0;38char &llvm::FuncletLayoutID = FuncletLayout::ID;39INITIALIZE_PASS(FuncletLayout, DEBUG_TYPE,40 "Contiguously Lay Out Funclets", false, false)41 42bool FuncletLayout::runOnMachineFunction(MachineFunction &F) {43 // Even though this gets information from getEHScopeMembership(), this pass is44 // only necessary for funclet-based EH personalities, in which these EH scopes45 // are outlined at the end.46 DenseMap<const MachineBasicBlock *, int> FuncletMembership =47 getEHScopeMembership(F);48 if (FuncletMembership.empty())49 return false;50 51 F.sort([&](MachineBasicBlock &X, MachineBasicBlock &Y) {52 auto FuncletX = FuncletMembership.find(&X);53 auto FuncletY = FuncletMembership.find(&Y);54 assert(FuncletX != FuncletMembership.end());55 assert(FuncletY != FuncletMembership.end());56 return FuncletX->second < FuncletY->second;57 });58 59 // Conservatively assume we changed something.60 return true;61}62