1 //===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements basic block placement transformations which result in 11 // funclets being contiguous. 12 // 13 //===----------------------------------------------------------------------===// 14 #include "llvm/CodeGen/Passes.h" 15 #include "llvm/CodeGen/Analysis.h" 16 #include "llvm/CodeGen/MachineFunction.h" 17 #include "llvm/CodeGen/MachineFunctionPass.h" 18 using namespace llvm; 19 20 #define DEBUG_TYPE "funclet-layout" 21 22 namespace { 23 class FuncletLayout : public MachineFunctionPass { 24 public: 25 static char ID; // Pass identification, replacement for typeid FuncletLayout()26 FuncletLayout() : MachineFunctionPass(ID) { 27 initializeFuncletLayoutPass(*PassRegistry::getPassRegistry()); 28 } 29 30 bool runOnMachineFunction(MachineFunction &F) override; 31 }; 32 } 33 34 char FuncletLayout::ID = 0; 35 char &llvm::FuncletLayoutID = FuncletLayout::ID; 36 INITIALIZE_PASS(FuncletLayout, "funclet-layout", 37 "Contiguously Lay Out Funclets", false, false) 38 runOnMachineFunction(MachineFunction & F)39bool FuncletLayout::runOnMachineFunction(MachineFunction &F) { 40 DenseMap<const MachineBasicBlock *, int> FuncletMembership = 41 getFuncletMembership(F); 42 if (FuncletMembership.empty()) 43 return false; 44 45 F.sort([&](MachineBasicBlock &X, MachineBasicBlock &Y) { 46 auto FuncletX = FuncletMembership.find(&X); 47 auto FuncletY = FuncletMembership.find(&Y); 48 assert(FuncletX != FuncletMembership.end()); 49 assert(FuncletY != FuncletMembership.end()); 50 return FuncletX->second < FuncletY->second; 51 }); 52 53 // Conservatively assume we changed something. 54 return true; 55 } 56