MachineFunctionPass.cpp revision 360784 
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/AliasAnalysis.h"
15#include "llvm/Analysis/BasicAliasAnalysis.h"
16#include "llvm/Analysis/DominanceFrontier.h"
17#include "llvm/Analysis/GlobalsModRef.h"
18#include "llvm/Analysis/IVUsers.h"
19#include "llvm/Analysis/LoopInfo.h"
20#include "llvm/Analysis/MemoryDependenceAnalysis.h"
21#include "llvm/Analysis/ScalarEvolution.h"
22#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
23#include "llvm/CodeGen/MachineFunction.h"
24#include "llvm/CodeGen/MachineModuleInfo.h"
25#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
26#include "llvm/CodeGen/Passes.h"
27#include "llvm/IR/Dominators.h"
28#include "llvm/IR/Function.h"
29
30using namespace llvm;
31using namespace ore;
32
33Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O,
34                                             const std::string &Banner) const {
35  return createMachineFunctionPrinterPass(O, Banner);
36}
37
38bool MachineFunctionPass::runOnFunction(Function &F) {
39  // Do not codegen any 'available_externally' functions at all, they have
40  // definitions outside the translation unit.
41  if (F.hasAvailableExternallyLinkage())
42    return false;
43
44  MachineModuleInfo &MMI = getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
45  MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
46
47  MachineFunctionProperties &MFProps = MF.getProperties();
48
49#ifndef NDEBUG
50  if (!MFProps.verifyRequiredProperties(RequiredProperties)) {
51    errs() << "MachineFunctionProperties required by " << getPassName()
52           << " pass are not met by function " << F.getName() << ".\n"
53           << "Required properties: ";
54    RequiredProperties.print(errs());
55    errs() << "\nCurrent properties: ";
56    MFProps.print(errs());
57    errs() << "\n";
58    llvm_unreachable("MachineFunctionProperties check failed");
59  }
60#endif
61  // Collect the MI count of the function before the pass.
62  unsigned CountBefore, CountAfter;
63
64  // Check if the user asked for size remarks.
65  bool ShouldEmitSizeRemarks =
66      F.getParent()->shouldEmitInstrCountChangedRemark();
67
68  // If we want size remarks, collect the number of MachineInstrs in our
69  // MachineFunction before the pass runs.
70  if (ShouldEmitSizeRemarks)
71    CountBefore = MF.getInstructionCount();
72
73  bool RV = runOnMachineFunction(MF);
74
75  if (ShouldEmitSizeRemarks) {
76    // We wanted size remarks. Check if there was a change to the number of
77    // MachineInstrs in the module. Emit a remark if there was a change.
78    CountAfter = MF.getInstructionCount();
79    if (CountBefore != CountAfter) {
80      MachineOptimizationRemarkEmitter MORE(MF, nullptr);
81      MORE.emit([&]() {
82        int64_t Delta = static_cast<int64_t>(CountAfter) -
83                        static_cast<int64_t>(CountBefore);
84        MachineOptimizationRemarkAnalysis R("size-info", "FunctionMISizeChange",
85                                            MF.getFunction().getSubprogram(),
86                                            &MF.front());
87        R << NV("Pass", getPassName())
88          << ": Function: " << NV("Function", F.getName()) << ": "
89          << "MI Instruction count changed from "
90          << NV("MIInstrsBefore", CountBefore) << " to "
91          << NV("MIInstrsAfter", CountAfter)
92          << "; Delta: " << NV("Delta", Delta);
93        return R;
94      });
95    }
96  }
97
98  MFProps.set(SetProperties);
99  MFProps.reset(ClearedProperties);
100  return RV;
101}
102
103void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
104  AU.addRequired<MachineModuleInfoWrapperPass>();
105  AU.addPreserved<MachineModuleInfoWrapperPass>();
106
107  // MachineFunctionPass preserves all LLVM IR passes, but there's no
108  // high-level way to express this. Instead, just list a bunch of
109  // passes explicitly. This does not include setPreservesCFG,
110  // because CodeGen overloads that to mean preserving the MachineBasicBlock
111  // CFG in addition to the LLVM IR CFG.
112  AU.addPreserved<BasicAAWrapperPass>();
113  AU.addPreserved<DominanceFrontierWrapperPass>();
114  AU.addPreserved<DominatorTreeWrapperPass>();
115  AU.addPreserved<AAResultsWrapperPass>();
116  AU.addPreserved<GlobalsAAWrapperPass>();
117  AU.addPreserved<IVUsersWrapperPass>();
118  AU.addPreserved<LoopInfoWrapperPass>();
119  AU.addPreserved<MemoryDependenceWrapperPass>();
120  AU.addPreserved<ScalarEvolutionWrapperPass>();
121  AU.addPreserved<SCEVAAWrapperPass>();
122
123  FunctionPass::getAnalysisUsage(AU);
124}
125