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   // TODO Implement --filter-passes.
  77   SmallString<0> BeforeStr, AfterStr;
  78   bool ShouldPrintChanged = PrintChanged != ChangePrinter::None &&
  79                             isFunctionInPrintList(MF.getName());
  80   if (ShouldPrintChanged) {
  81     raw_svector_ostream OS(BeforeStr);
  82     MF.print(OS);
  83   }
  84
  85   bool RV = runOnMachineFunction(MF);
  86
  87   if (ShouldEmitSizeRemarks) {
  88     // We wanted size remarks. Check if there was a change to the number of
  89     // MachineInstrs in the module. Emit a remark if there was a change.
  90     CountAfter = MF.getInstructionCount();
  91     if (CountBefore != CountAfter) {
  92       MachineOptimizationRemarkEmitter MORE(MF, nullptr);
  93       MORE.emit([&]() {
  94         int64_t Delta = static_cast<int64_t>(CountAfter) -
  95                         static_cast<int64_t>(CountBefore);
  96         MachineOptimizationRemarkAnalysis R("size-info", "FunctionMISizeChange",
  97                                             MF.getFunction().getSubprogram(),
  98                                             &MF.front());
  99         R << NV("Pass", getPassName())
 100           << ": Function: " << NV("Function", F.getName()) << ": "
 101           << "MI Instruction count changed from "
 102           << NV("MIInstrsBefore", CountBefore) << " to "
 103           << NV("MIInstrsAfter", CountAfter)
 104           << "; Delta: " << NV("Delta", Delta);
 105         return R;
 106       });
 107     }
 108   }
 109
 110   MFProps.set(SetProperties);
 111   MFProps.reset(ClearedProperties);
 112
 113   // For --print-changed, print if the serialized MF has changed. Modes other
 114   // than quiet/verbose are unimplemented and treated the same as 'quiet'.
 115   if (ShouldPrintChanged) {
 116     raw_svector_ostream OS(AfterStr);
 117     MF.print(OS);
 118     if (BeforeStr != AfterStr) {
 119       StringRef Arg;
 120       if (const PassInfo *PI = Pass::lookupPassInfo(getPassID()))
 121         Arg = PI->getPassArgument();
 122       errs() << ("*** IR Dump After " + getPassName() + " (" + Arg + ") on " +
 123                  MF.getName() + " ***\n");
 124       switch (PrintChanged) {
 125       case ChangePrinter::None:
 126         llvm_unreachable("");
 127       case ChangePrinter::Quiet:
 128       case ChangePrinter::Verbose:
 129       case ChangePrinter::DotCfgQuiet:   // unimplemented
 130       case ChangePrinter::DotCfgVerbose: // unimplemented
 131         errs() << AfterStr;
 132         break;
 133       case ChangePrinter::DiffQuiet:
 134       case ChangePrinter::DiffVerbose:
 135       case ChangePrinter::ColourDiffQuiet:
 136       case ChangePrinter::ColourDiffVerbose: {
 137         bool Color = llvm::is_contained(
 138             {ChangePrinter::ColourDiffQuiet, ChangePrinter::ColourDiffVerbose},
 139             PrintChanged.getValue());
 140         StringRef Removed = Color ? "\033[31m-%l\033[0m\n" : "-%l\n";
 141         StringRef Added = Color ? "\033[32m+%l\033[0m\n" : "+%l\n";
 142         StringRef NoChange = " %l\n";
 143         errs() << doSystemDiff(BeforeStr, AfterStr, Removed, Added, NoChange);
 144         break;
 145       }
 146       }
 147     } else if (llvm::is_contained({ChangePrinter::Verbose,
 148                                    ChangePrinter::DiffVerbose,
 149                                    ChangePrinter::ColourDiffVerbose},
 150                                   PrintChanged.getValue())) {
 151       errs() << ("*** IR Dump After " + getPassName() + " on " + MF.getName() +
 152                  " omitted because no change ***\n");
 153     }
 154   }
 155   return RV;
 156 }
 157
 158 void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
 159   AU.addRequired<MachineModuleInfoWrapperPass>();
 160   AU.addPreserved<MachineModuleInfoWrapperPass>();
 161
 162   // MachineFunctionPass preserves all LLVM IR passes, but there's no
 163   // high-level way to express this. Instead, just list a bunch of
 164   // passes explicitly. This does not include setPreservesCFG,
 165   // because CodeGen overloads that to mean preserving the MachineBasicBlock
 166   // CFG in addition to the LLVM IR CFG.
 167   AU.addPreserved<BasicAAWrapperPass>();
 168   AU.addPreserved<DominanceFrontierWrapperPass>();
 169   AU.addPreserved<DominatorTreeWrapperPass>();
 170   AU.addPreserved<AAResultsWrapperPass>();
 171   AU.addPreserved<GlobalsAAWrapperPass>();
 172   AU.addPreserved<IVUsersWrapperPass>();
 173   AU.addPreserved<LoopInfoWrapperPass>();
 174   AU.addPreserved<MemoryDependenceWrapperPass>();
 175   AU.addPreserved<ScalarEvolutionWrapperPass>();
 176   AU.addPreserved<SCEVAAWrapperPass>();
 177
 178   FunctionPass::getAnalysisUsage(AU);
 179 }