llvm/lib/CodeGen/MachineFunctionPass.cpp

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