1//===-- MachineFunctionPass.cpp -------------------------------------------===//
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-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the definitions of the MachineFunctionPass members.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/CodeGen/MachineFunctionPass.h"
14#include "llvm/Analysis/BasicAliasAnalysis.h"
15#include "llvm/Analysis/DominanceFrontier.h"
16#include "llvm/Analysis/GlobalsModRef.h"
17#include "llvm/Analysis/IVUsers.h"
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/Analysis/MemoryDependenceAnalysis.h"
20#include "llvm/Analysis/ScalarEvolution.h"
21#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
22#include "llvm/CodeGen/MachineFunction.h"
23#include "llvm/CodeGen/MachineModuleInfo.h"
24#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
25#include "llvm/CodeGen/Passes.h"
26#include "llvm/IR/Dominators.h"
27#include "llvm/IR/Function.h"
28
29using namespace llvm;
30using namespace ore;
31
32Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O,
33                                             const std::string &Banner) const {
34  return createMachineFunctionPrinterPass(O, Banner);
35}
36
37bool MachineFunctionPass::runOnFunction(Function &F) {
38  // Do not codegen any 'available_externally' functions at all, they have
39  // definitions outside the translation unit.
40  if (F.hasAvailableExternallyLinkage())
41    return false;
42
43  MachineModuleInfo &MMI = getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
44  MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
45
46  MachineFunctionProperties &MFProps = MF.getProperties();
47
48#ifndef NDEBUG
49  if (!MFProps.verifyRequiredProperties(RequiredProperties)) {
50    errs() << "MachineFunctionProperties required by " << getPassName()
51           << " pass are not met by function " << F.getName() << ".\n"
52           << "Required properties: ";
53    RequiredProperties.print(errs());
54    errs() << "\nCurrent properties: ";
55    MFProps.print(errs());
56    errs() << "\n";
57    llvm_unreachable("MachineFunctionProperties check failed");
58  }
59#endif
60  // Collect the MI count of the function before the pass.
61  unsigned CountBefore, CountAfter;
62
63  // Check if the user asked for size remarks.
64  bool ShouldEmitSizeRemarks =
65      F.getParent()->shouldEmitInstrCountChangedRemark();
66
67  // If we want size remarks, collect the number of MachineInstrs in our
68  // MachineFunction before the pass runs.
69  if (ShouldEmitSizeRemarks)
70    CountBefore = MF.getInstructionCount();
71
72  bool RV = runOnMachineFunction(MF);
73
74  if (ShouldEmitSizeRemarks) {
75    // We wanted size remarks. Check if there was a change to the number of
76    // MachineInstrs in the module. Emit a remark if there was a change.
77    CountAfter = MF.getInstructionCount();
78    if (CountBefore != CountAfter) {
79      MachineOptimizationRemarkEmitter MORE(MF, nullptr);
80      MORE.emit([&]() {
81        int64_t Delta = static_cast<int64_t>(CountAfter) -
82                        static_cast<int64_t>(CountBefore);
83        MachineOptimizationRemarkAnalysis R("size-info", "FunctionMISizeChange",
84                                            MF.getFunction().getSubprogram(),
85                                            &MF.front());
86        R << NV("Pass", getPassName())
87          << ": Function: " << NV("Function", F.getName()) << ": "
88          << "MI Instruction count changed from "
89          << NV("MIInstrsBefore", CountBefore) << " to "
90          << NV("MIInstrsAfter", CountAfter)
91          << "; Delta: " << NV("Delta", Delta);
92        return R;
93      });
94    }
95  }
96
97  MFProps.set(SetProperties);
98  MFProps.reset(ClearedProperties);
99  return RV;
100}
101
102void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
103  AU.addRequired<MachineModuleInfoWrapperPass>();
104  AU.addPreserved<MachineModuleInfoWrapperPass>();
105
106  // MachineFunctionPass preserves all LLVM IR passes, but there's no
107  // high-level way to express this. Instead, just list a bunch of
108  // passes explicitly. This does not include setPreservesCFG,
109  // because CodeGen overloads that to mean preserving the MachineBasicBlock
110  // CFG in addition to the LLVM IR CFG.
111  AU.addPreserved<BasicAAWrapperPass>();
112  AU.addPreserved<DominanceFrontierWrapperPass>();
113  AU.addPreserved<DominatorTreeWrapperPass>();
114  AU.addPreserved<AAResultsWrapperPass>();
115  AU.addPreserved<GlobalsAAWrapperPass>();
116  AU.addPreserved<IVUsersWrapperPass>();
117  AU.addPreserved<LoopInfoWrapperPass>();
118  AU.addPreserved<MemoryDependenceWrapperPass>();
119  AU.addPreserved<ScalarEvolutionWrapperPass>();
120  AU.addPreserved<SCEVAAWrapperPass>();
121
122  FunctionPass::getAnalysisUsage(AU);
123}
124