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 33 using namespace llvm; 34 using namespace ore; 35 36 static 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(false)); 40 41 Pass *MachineFunctionPass::createPrinterPass(raw_ostream &O, 42 const std::string &Banner) const { 43 return createMachineFunctionPrinterPass(O, Banner); 44 } 45 46 bool 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(getPassID())) 87 PassID = PI->getPassArgument(); 88 } 89 const bool IsInterestingPass = isPassInPrintList(PassID); 90 const bool ShouldPrintChanged = PrintChanged != ChangePrinter::None && 91 IsInterestingPass && 92 isFunctionInPrintList(MF.getName()); 93 if (ShouldPrintChanged) { 94 raw_svector_ostream OS(BeforeStr); 95 MF.print(OS); 96 } 97 98 MFProps.reset(ClearedProperties); 99 100 bool RV; 101 if (DroppedVarStatsMIR) { 102 DroppedVariableStatsMIR DroppedVarStatsMF; 103 auto PassName = getPassName(); 104 DroppedVarStatsMF.runBeforePass(PassName, &MF); 105 RV = runOnMachineFunction(MF); 106 DroppedVarStatsMF.runAfterPass(PassName, &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([&]() { 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 {ChangePrinter::ColourDiffQuiet, ChangePrinter::ColourDiffVerbose}, 161 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(BeforeStr, AfterStr, Removed, Added, NoChange); 166 break; 167 } 168 } 169 } else if (llvm::is_contained({ChangePrinter::Verbose, 170 ChangePrinter::DiffVerbose, 171 ChangePrinter::ColourDiffVerbose}, 172 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 } 183 184 void 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