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
30 using namespace llvm;
31 using namespace ore;
32
createPrinterPass(raw_ostream & O,const std::string & Banner) const33 Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O,
34 const std::string &Banner) const {
35 return createMachineFunctionPrinterPass(O, Banner);
36 }
37
runOnFunction(Function & F)38 bool 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
getAnalysisUsage(AnalysisUsage & AU) const103 void 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