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