xref: /freebsd/contrib/llvm-project/llvm/lib/CodeGen/LazyMachineBlockFrequencyInfo.cpp (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1*0b57cec5SDimitry Andric ///===- LazyMachineBlockFrequencyInfo.cpp - Lazy Machine Block Frequency --===//
2*0b57cec5SDimitry Andric ///
3*0b57cec5SDimitry Andric /// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*0b57cec5SDimitry Andric /// See https://llvm.org/LICENSE.txt for license information.
5*0b57cec5SDimitry Andric /// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*0b57cec5SDimitry Andric ///
7*0b57cec5SDimitry Andric ///===---------------------------------------------------------------------===//
8*0b57cec5SDimitry Andric /// \file
9*0b57cec5SDimitry Andric /// This is an alternative analysis pass to MachineBlockFrequencyInfo.  The
10*0b57cec5SDimitry Andric /// difference is that with this pass the block frequencies are not computed
11*0b57cec5SDimitry Andric /// when the analysis pass is executed but rather when the BFI result is
12*0b57cec5SDimitry Andric /// explicitly requested by the analysis client.
13*0b57cec5SDimitry Andric ///
14*0b57cec5SDimitry Andric ///===---------------------------------------------------------------------===//
15*0b57cec5SDimitry Andric 
16*0b57cec5SDimitry Andric #include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
17*0b57cec5SDimitry Andric 
18*0b57cec5SDimitry Andric using namespace llvm;
19*0b57cec5SDimitry Andric 
20*0b57cec5SDimitry Andric #define DEBUG_TYPE "lazy-machine-block-freq"
21*0b57cec5SDimitry Andric 
22*0b57cec5SDimitry Andric INITIALIZE_PASS_BEGIN(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
23*0b57cec5SDimitry Andric                       "Lazy Machine Block Frequency Analysis", true, true)
24*0b57cec5SDimitry Andric INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
25*0b57cec5SDimitry Andric INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
26*0b57cec5SDimitry Andric INITIALIZE_PASS_END(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
27*0b57cec5SDimitry Andric                     "Lazy Machine Block Frequency Analysis", true, true)
28*0b57cec5SDimitry Andric 
29*0b57cec5SDimitry Andric char LazyMachineBlockFrequencyInfoPass::ID = 0;
30*0b57cec5SDimitry Andric 
31*0b57cec5SDimitry Andric LazyMachineBlockFrequencyInfoPass::LazyMachineBlockFrequencyInfoPass()
32*0b57cec5SDimitry Andric     : MachineFunctionPass(ID) {
33*0b57cec5SDimitry Andric   initializeLazyMachineBlockFrequencyInfoPassPass(
34*0b57cec5SDimitry Andric       *PassRegistry::getPassRegistry());
35*0b57cec5SDimitry Andric }
36*0b57cec5SDimitry Andric 
37*0b57cec5SDimitry Andric void LazyMachineBlockFrequencyInfoPass::print(raw_ostream &OS,
38*0b57cec5SDimitry Andric                                               const Module *M) const {
39*0b57cec5SDimitry Andric   getBFI().print(OS, M);
40*0b57cec5SDimitry Andric }
41*0b57cec5SDimitry Andric 
42*0b57cec5SDimitry Andric void LazyMachineBlockFrequencyInfoPass::getAnalysisUsage(
43*0b57cec5SDimitry Andric     AnalysisUsage &AU) const {
44*0b57cec5SDimitry Andric   AU.addRequired<MachineBranchProbabilityInfo>();
45*0b57cec5SDimitry Andric   AU.setPreservesAll();
46*0b57cec5SDimitry Andric   MachineFunctionPass::getAnalysisUsage(AU);
47*0b57cec5SDimitry Andric }
48*0b57cec5SDimitry Andric 
49*0b57cec5SDimitry Andric void LazyMachineBlockFrequencyInfoPass::releaseMemory() {
50*0b57cec5SDimitry Andric   OwnedMBFI.reset();
51*0b57cec5SDimitry Andric   OwnedMLI.reset();
52*0b57cec5SDimitry Andric   OwnedMDT.reset();
53*0b57cec5SDimitry Andric }
54*0b57cec5SDimitry Andric 
55*0b57cec5SDimitry Andric MachineBlockFrequencyInfo &
56*0b57cec5SDimitry Andric LazyMachineBlockFrequencyInfoPass::calculateIfNotAvailable() const {
57*0b57cec5SDimitry Andric   auto *MBFI = getAnalysisIfAvailable<MachineBlockFrequencyInfo>();
58*0b57cec5SDimitry Andric   if (MBFI) {
59*0b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "MachineBlockFrequencyInfo is available\n");
60*0b57cec5SDimitry Andric     return *MBFI;
61*0b57cec5SDimitry Andric   }
62*0b57cec5SDimitry Andric 
63*0b57cec5SDimitry Andric   auto &MBPI = getAnalysis<MachineBranchProbabilityInfo>();
64*0b57cec5SDimitry Andric   auto *MLI = getAnalysisIfAvailable<MachineLoopInfo>();
65*0b57cec5SDimitry Andric   auto *MDT = getAnalysisIfAvailable<MachineDominatorTree>();
66*0b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "Building MachineBlockFrequencyInfo on the fly\n");
67*0b57cec5SDimitry Andric   LLVM_DEBUG(if (MLI) dbgs() << "LoopInfo is available\n");
68*0b57cec5SDimitry Andric 
69*0b57cec5SDimitry Andric   if (!MLI) {
70*0b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "Building LoopInfo on the fly\n");
71*0b57cec5SDimitry Andric     // First create a dominator tree.
72*0b57cec5SDimitry Andric     LLVM_DEBUG(if (MDT) dbgs() << "DominatorTree is available\n");
73*0b57cec5SDimitry Andric 
74*0b57cec5SDimitry Andric     if (!MDT) {
75*0b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "Building DominatorTree on the fly\n");
76*0b57cec5SDimitry Andric       OwnedMDT = make_unique<MachineDominatorTree>();
77*0b57cec5SDimitry Andric       OwnedMDT->getBase().recalculate(*MF);
78*0b57cec5SDimitry Andric       MDT = OwnedMDT.get();
79*0b57cec5SDimitry Andric     }
80*0b57cec5SDimitry Andric 
81*0b57cec5SDimitry Andric     // Generate LoopInfo from it.
82*0b57cec5SDimitry Andric     OwnedMLI = make_unique<MachineLoopInfo>();
83*0b57cec5SDimitry Andric     OwnedMLI->getBase().analyze(MDT->getBase());
84*0b57cec5SDimitry Andric     MLI = OwnedMLI.get();
85*0b57cec5SDimitry Andric   }
86*0b57cec5SDimitry Andric 
87*0b57cec5SDimitry Andric   OwnedMBFI = make_unique<MachineBlockFrequencyInfo>();
88*0b57cec5SDimitry Andric   OwnedMBFI->calculate(*MF, MBPI, *MLI);
89*0b57cec5SDimitry Andric   return *OwnedMBFI.get();
90*0b57cec5SDimitry Andric }
91*0b57cec5SDimitry Andric 
92*0b57cec5SDimitry Andric bool LazyMachineBlockFrequencyInfoPass::runOnMachineFunction(
93*0b57cec5SDimitry Andric     MachineFunction &F) {
94*0b57cec5SDimitry Andric   MF = &F;
95*0b57cec5SDimitry Andric   return false;
96*0b57cec5SDimitry Andric }
97