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/OptimizationRemarkEmitter.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 #include "llvm/IR/Module.h"
30 #include "llvm/IR/PrintPasses.h"
31
32 using namespace llvm;
33 using namespace ore;
34
createPrinterPass(raw_ostream & O,const std::string & Banner) const35 Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O,
36 const std::string &Banner) const {
37 return createMachineFunctionPrinterPass(O, Banner);
38 }
39
runOnFunction(Function & F)40 bool MachineFunctionPass::runOnFunction(Function &F) {
41 // Do not codegen any 'available_externally' functions at all, they have
42 // definitions outside the translation unit.
43 if (F.hasAvailableExternallyLinkage())
44 return false;
45
46 MachineModuleInfo &MMI = getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
47 MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
48
49 MachineFunctionProperties &MFProps = MF.getProperties();
50
51 #ifndef NDEBUG
52 if (!MFProps.verifyRequiredProperties(RequiredProperties)) {
53 errs() << "MachineFunctionProperties required by " << getPassName()
54 << " pass are not met by function " << F.getName() << ".\n"
55 << "Required properties: ";
56 RequiredProperties.print(errs());
57 errs() << "\nCurrent properties: ";
58 MFProps.print(errs());
59 errs() << "\n";
60 llvm_unreachable("MachineFunctionProperties check failed");
61 }
62 #endif
63 // Collect the MI count of the function before the pass.
64 unsigned CountBefore, CountAfter;
65
66 // Check if the user asked for size remarks.
67 bool ShouldEmitSizeRemarks =
68 F.getParent()->shouldEmitInstrCountChangedRemark();
69
70 // If we want size remarks, collect the number of MachineInstrs in our
71 // MachineFunction before the pass runs.
72 if (ShouldEmitSizeRemarks)
73 CountBefore = MF.getInstructionCount();
74
75 // For --print-changed, if the function name is a candidate, save the
76 // serialized MF to be compared later.
77 SmallString<0> BeforeStr, AfterStr;
78 StringRef PassID;
79 if (PrintChanged != ChangePrinter::None) {
80 if (const PassInfo *PI = Pass::lookupPassInfo(getPassID()))
81 PassID = PI->getPassArgument();
82 }
83 const bool IsInterestingPass = isPassInPrintList(PassID);
84 const bool ShouldPrintChanged = PrintChanged != ChangePrinter::None &&
85 IsInterestingPass &&
86 isFunctionInPrintList(MF.getName());
87 if (ShouldPrintChanged) {
88 raw_svector_ostream OS(BeforeStr);
89 MF.print(OS);
90 }
91
92 MFProps.reset(ClearedProperties);
93
94 bool RV = runOnMachineFunction(MF);
95
96 if (ShouldEmitSizeRemarks) {
97 // We wanted size remarks. Check if there was a change to the number of
98 // MachineInstrs in the module. Emit a remark if there was a change.
99 CountAfter = MF.getInstructionCount();
100 if (CountBefore != CountAfter) {
101 MachineOptimizationRemarkEmitter MORE(MF, nullptr);
102 MORE.emit([&]() {
103 int64_t Delta = static_cast<int64_t>(CountAfter) -
104 static_cast<int64_t>(CountBefore);
105 MachineOptimizationRemarkAnalysis R("size-info", "FunctionMISizeChange",
106 MF.getFunction().getSubprogram(),
107 &MF.front());
108 R << NV("Pass", getPassName())
109 << ": Function: " << NV("Function", F.getName()) << ": "
110 << "MI Instruction count changed from "
111 << NV("MIInstrsBefore", CountBefore) << " to "
112 << NV("MIInstrsAfter", CountAfter)
113 << "; Delta: " << NV("Delta", Delta);
114 return R;
115 });
116 }
117 }
118
119 MFProps.set(SetProperties);
120
121 // For --print-changed, print if the serialized MF has changed. Modes other
122 // than quiet/verbose are unimplemented and treated the same as 'quiet'.
123 if (ShouldPrintChanged || !IsInterestingPass) {
124 if (ShouldPrintChanged) {
125 raw_svector_ostream OS(AfterStr);
126 MF.print(OS);
127 }
128 if (IsInterestingPass && BeforeStr != AfterStr) {
129 errs() << ("*** IR Dump After " + getPassName() + " (" + PassID +
130 ") on " + MF.getName() + " ***\n");
131 switch (PrintChanged) {
132 case ChangePrinter::None:
133 llvm_unreachable("");
134 case ChangePrinter::Quiet:
135 case ChangePrinter::Verbose:
136 case ChangePrinter::DotCfgQuiet: // unimplemented
137 case ChangePrinter::DotCfgVerbose: // unimplemented
138 errs() << AfterStr;
139 break;
140 case ChangePrinter::DiffQuiet:
141 case ChangePrinter::DiffVerbose:
142 case ChangePrinter::ColourDiffQuiet:
143 case ChangePrinter::ColourDiffVerbose: {
144 bool Color = llvm::is_contained(
145 {ChangePrinter::ColourDiffQuiet, ChangePrinter::ColourDiffVerbose},
146 PrintChanged.getValue());
147 StringRef Removed = Color ? "\033[31m-%l\033[0m\n" : "-%l\n";
148 StringRef Added = Color ? "\033[32m+%l\033[0m\n" : "+%l\n";
149 StringRef NoChange = " %l\n";
150 errs() << doSystemDiff(BeforeStr, AfterStr, Removed, Added, NoChange);
151 break;
152 }
153 }
154 } else if (llvm::is_contained({ChangePrinter::Verbose,
155 ChangePrinter::DiffVerbose,
156 ChangePrinter::ColourDiffVerbose},
157 PrintChanged.getValue())) {
158 const char *Reason =
159 IsInterestingPass ? " omitted because no change" : " filtered out";
160 errs() << "*** IR Dump After " << getPassName();
161 if (!PassID.empty())
162 errs() << " (" << PassID << ")";
163 errs() << " on " << MF.getName() + Reason + " ***\n";
164 }
165 }
166 return RV;
167 }
168
getAnalysisUsage(AnalysisUsage & AU) const169 void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
170 AU.addRequired<MachineModuleInfoWrapperPass>();
171 AU.addPreserved<MachineModuleInfoWrapperPass>();
172
173 // MachineFunctionPass preserves all LLVM IR passes, but there's no
174 // high-level way to express this. Instead, just list a bunch of
175 // passes explicitly. This does not include setPreservesCFG,
176 // because CodeGen overloads that to mean preserving the MachineBasicBlock
177 // CFG in addition to the LLVM IR CFG.
178 AU.addPreserved<BasicAAWrapperPass>();
179 AU.addPreserved<DominanceFrontierWrapperPass>();
180 AU.addPreserved<DominatorTreeWrapperPass>();
181 AU.addPreserved<AAResultsWrapperPass>();
182 AU.addPreserved<GlobalsAAWrapperPass>();
183 AU.addPreserved<IVUsersWrapperPass>();
184 AU.addPreserved<LoopInfoWrapperPass>();
185 AU.addPreserved<MemoryDependenceWrapperPass>();
186 AU.addPreserved<ScalarEvolutionWrapperPass>();
187 AU.addPreserved<SCEVAAWrapperPass>();
188
189 FunctionPass::getAnalysisUsage(AU);
190 }
191