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