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/BranchProbabilityInfo.h"
16#include "llvm/Analysis/DominanceFrontier.h"
17#include "llvm/Analysis/GlobalsModRef.h"
18#include "llvm/Analysis/IVUsers.h"
19#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
20#include "llvm/Analysis/LazyBranchProbabilityInfo.h"
21#include "llvm/Analysis/LoopInfo.h"
22#include "llvm/Analysis/MemoryDependenceAnalysis.h"
23#include "llvm/Analysis/OptimizationRemarkEmitter.h"
24#include "llvm/Analysis/PostDominators.h"
25#include "llvm/Analysis/ScalarEvolution.h"
26#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
27#include "llvm/CodeGen/DroppedVariableStatsMIR.h"
28#include "llvm/CodeGen/MachineFunction.h"
29#include "llvm/CodeGen/MachineModuleInfo.h"
30#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
31#include "llvm/CodeGen/Passes.h"
32#include "llvm/IR/Dominators.h"
33#include "llvm/IR/Function.h"
34#include "llvm/IR/Module.h"
35#include "llvm/IR/PrintPasses.h"
36
37using namespace llvm;
38using namespace ore;
39
40static cl::opt<bool> DroppedVarStatsMIR(
41 "dropped-variable-stats-mir", cl::Hidden,
42 cl::desc("Dump dropped debug variables stats for MIR passes"),
43 cl::init(Val: false));
44
45Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O,
46 const std::string &Banner) const {
47 return createMachineFunctionPrinterPass(OS&: O, Banner);
48}
49
50bool MachineFunctionPass::runOnFunction(Function &F) {
51 // Do not codegen any 'available_externally' functions at all, they have
52 // definitions outside the translation unit.
53 if (F.hasAvailableExternallyLinkage())
54 return false;
55
56 MachineModuleInfo &MMI = getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
57 MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
58
59 MachineFunctionProperties &MFProps = MF.getProperties();
60
61#ifndef NDEBUG
62 if (!MFProps.verifyRequiredProperties(RequiredProperties)) {
63 errs() << "MachineFunctionProperties required by " << getPassName()
64 << " pass are not met by function " << F.getName() << ".\n"
65 << "Required properties: ";
66 RequiredProperties.print(errs());
67 errs() << "\nCurrent properties: ";
68 MFProps.print(errs());
69 errs() << "\n";
70 llvm_unreachable("MachineFunctionProperties check failed");
71 }
72#endif
73 // Collect the MI count of the function before the pass.
74 unsigned CountBefore, CountAfter;
75
76 // Check if the user asked for size remarks.
77 bool ShouldEmitSizeRemarks =
78 F.getParent()->shouldEmitInstrCountChangedRemark();
79
80 // If we want size remarks, collect the number of MachineInstrs in our
81 // MachineFunction before the pass runs.
82 if (ShouldEmitSizeRemarks)
83 CountBefore = MF.getInstructionCount();
84
85 // For --print-changed, if the function name is a candidate, save the
86 // serialized MF to be compared later.
87 SmallString<0> BeforeStr, AfterStr;
88 StringRef PassID;
89 if (PrintChanged != ChangePrinter::None) {
90 if (const PassInfo *PI = Pass::lookupPassInfo(TI: getPassID()))
91 PassID = PI->getPassArgument();
92 }
93 const bool IsInterestingPass = isPassInPrintList(PassName: PassID);
94 const bool ShouldPrintChanged = PrintChanged != ChangePrinter::None &&
95 IsInterestingPass &&
96 isFunctionInPrintList(FunctionName: MF.getName());
97 if (ShouldPrintChanged) {
98 raw_svector_ostream OS(BeforeStr);
99 MF.print(OS);
100 }
101
102 MFProps.reset(MFP: ClearedProperties);
103
104 bool RV;
105 if (DroppedVarStatsMIR) {
106 DroppedVariableStatsMIR DroppedVarStatsMF;
107 auto PassName = getPassName();
108 DroppedVarStatsMF.runBeforePass(PassID: PassName, MF: &MF);
109 RV = runOnMachineFunction(MF);
110 DroppedVarStatsMF.runAfterPass(PassID: PassName, MF: &MF);
111 } else {
112 RV = runOnMachineFunction(MF);
113 }
114
115 if (ShouldEmitSizeRemarks) {
116 // We wanted size remarks. Check if there was a change to the number of
117 // MachineInstrs in the module. Emit a remark if there was a change.
118 CountAfter = MF.getInstructionCount();
119 if (CountBefore != CountAfter) {
120 MachineOptimizationRemarkEmitter MORE(MF, nullptr);
121 MORE.emit(RemarkBuilder: [&]() {
122 int64_t Delta = static_cast<int64_t>(CountAfter) -
123 static_cast<int64_t>(CountBefore);
124 MachineOptimizationRemarkAnalysis R("size-info", "FunctionMISizeChange",
125 MF.getFunction().getSubprogram(),
126 &MF.front());
127 R << NV("Pass", getPassName())
128 << ": Function: " << NV("Function", F.getName()) << ": "
129 << "MI Instruction count changed from "
130 << NV("MIInstrsBefore", CountBefore) << " to "
131 << NV("MIInstrsAfter", CountAfter)
132 << "; Delta: " << NV("Delta", Delta);
133 return R;
134 });
135 }
136 }
137
138 MFProps.set(SetProperties);
139
140 // For --print-changed, print if the serialized MF has changed. Modes other
141 // than quiet/verbose are unimplemented and treated the same as 'quiet'.
142 if (ShouldPrintChanged || !IsInterestingPass) {
143 if (ShouldPrintChanged) {
144 raw_svector_ostream OS(AfterStr);
145 MF.print(OS);
146 }
147 if (IsInterestingPass && BeforeStr != AfterStr) {
148 errs() << ("*** IR Dump After " + getPassName() + " (" + PassID +
149 ") on " + MF.getName() + " ***\n");
150 switch (PrintChanged) {
151 case ChangePrinter::None:
152 llvm_unreachable("");
153 case ChangePrinter::Quiet:
154 case ChangePrinter::Verbose:
155 case ChangePrinter::DotCfgQuiet: // unimplemented
156 case ChangePrinter::DotCfgVerbose: // unimplemented
157 errs() << AfterStr;
158 break;
159 case ChangePrinter::DiffQuiet:
160 case ChangePrinter::DiffVerbose:
161 case ChangePrinter::ColourDiffQuiet:
162 case ChangePrinter::ColourDiffVerbose: {
163 bool Color = llvm::is_contained(
164 Set: {ChangePrinter::ColourDiffQuiet, ChangePrinter::ColourDiffVerbose},
165 Element: PrintChanged.getValue());
166 StringRef Removed = Color ? "\033[31m-%l\033[0m\n" : "-%l\n";
167 StringRef Added = Color ? "\033[32m+%l\033[0m\n" : "+%l\n";
168 StringRef NoChange = " %l\n";
169 errs() << doSystemDiff(Before: BeforeStr, After: AfterStr, OldLineFormat: Removed, NewLineFormat: Added, UnchangedLineFormat: NoChange);
170 break;
171 }
172 }
173 } else if (llvm::is_contained(Set: {ChangePrinter::Verbose,
174 ChangePrinter::DiffVerbose,
175 ChangePrinter::ColourDiffVerbose},
176 Element: PrintChanged.getValue())) {
177 const char *Reason =
178 IsInterestingPass ? " omitted because no change" : " filtered out";
179 errs() << "*** IR Dump After " << getPassName();
180 if (!PassID.empty())
181 errs() << " (" << PassID << ")";
182 errs() << " on " << MF.getName() + Reason + " ***\n";
183 }
184 }
185 return RV;
186}
187
188void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
189 AU.addRequired<MachineModuleInfoWrapperPass>();
190 AU.addPreserved<MachineModuleInfoWrapperPass>();
191
192 // MachineFunctionPass preserves all LLVM IR passes, but there's no
193 // high-level way to express this. Instead, just list a bunch of
194 // passes explicitly. This does not include setPreservesCFG,
195 // because CodeGen overloads that to mean preserving the MachineBasicBlock
196 // CFG in addition to the LLVM IR CFG.
197 AU.addPreserved<BasicAAWrapperPass>();
198 AU.addPreserved<DominanceFrontierWrapperPass>();
199 AU.addPreserved<DominatorTreeWrapperPass>();
200 AU.addPreserved<PostDominatorTreeWrapperPass>();
201 AU.addPreserved<BranchProbabilityInfoWrapperPass>();
202 AU.addPreserved<LazyBranchProbabilityInfoPass>();
203 AU.addPreserved<LazyBlockFrequencyInfoPass>();
204 AU.addPreserved<AAResultsWrapperPass>();
205 AU.addPreserved<GlobalsAAWrapperPass>();
206 AU.addPreserved<IVUsersWrapperPass>();
207 AU.addPreserved<LoopInfoWrapperPass>();
208 AU.addPreserved<MemoryDependenceWrapperPass>();
209 AU.addPreserved<ScalarEvolutionWrapperPass>();
210 AU.addPreserved<SCEVAAWrapperPass>();
211
212 FunctionPass::getAnalysisUsage(AU);
213}
214